ASHRAE Pocket Guide IP 8th edition 2013.pdf

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ASHRAE POCKET GUIDE for Air Conditioning, Heating, Ventilation, Refrigeration (I-P Edition) 8th Edition

ASHRAE · 1791 Tullie Circle, NE Atlanta, GA 30329 · www.ashrae.org

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© 1987, 1989, 1993, 1997, 2001, 2005, 2009, 2013 ASHRAE All rights reserved. Printed in the United States of America ISBN 978-1-936504-62-6 Product code: 90074 10/14 ASHRAE is a registered trademark in the U.S. Patent and Trademark Office, owned by the American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. No part of this manual may be reproduced without permission in writing from ASHRAE, except by a reviewer who may quote brief passages or reproduce illustrations in a review with appropriate credit, nor may any part of this book be reproduced, stored in a retrieval system, or transmitted in any way or by any means—electronic, photocopying, recording, or other—without permission in writing from ASHRAE. Requests for permission should be submitted at www.ashrae.org/permissions. ASHRAE has compiled this publication with care, but ASHRAE has not investigated, and ASHRAE expressly disclaims any duty to investigate, any product, service, process, procedure, design, or the like that may be described herein. The appearance of any technical data or editorial material in this publication does not constitute endorsement, warranty, or guaranty by ASHRAE of any product, service, process, procedure, design, or the like. ASHRAE does not warrant that the information in this publication is free of errors, and ASHRAE does not necessarily agree with any statement or opinion in this publication. The entire risk of the use of any information in this publication is assumed by the user.

Library of Congress Cataloging-in-Publication Data ASHRAE pocket guide for air conditioning, heating, ventilation, refrigeration. -- 8th edition, I-P edition. pages cm Includes index. Summary: "Ready reference for HVAC engineers whose mobility keeps them from easy access to the ASHRAE Handbooks; revised from 2009 edition, includes information from Handbooks and ASHRAE Standards 62.1, 62.2, 15, and 55 abridged or reduced to fit smaller page size"-- Provided by publisher. ISBN 978-1-936504-62-6 (softcover : alk. paper) 1. Heating--Equipment and supplies--Handbooks, manuals, etc. 2. Ventilation--Handbooks, manuals, etc. 3. Air conditioning--Handbooks, manuals, etc. 4. Refrigeration and refrigerating machinery-Handbooks, manuals, etc. I. American Society of Heating, Refrigerating and Air-Conditioning Engineers. II. Title: Pocket guide for air conditioning, heating, ventilation, refrigeration. TH7011.P63 2013 697.9'2--dc23 2013044820 ASHRAE Staff

Special Publications Mark S. Owen, Editor/Group Manager of Handbook and Special Publications Cindy Sheffield Michaels, Managing Editor James Madison Walker, Associate Editor Roberta Hirschbuehler, Assistant Editor Sarah Boyle, Assistant Editor Michshell Phillips, Editorial Coordinator Publishing Services David Soltis, Group Manager of Publishing Services and Electronic Communications Jayne Jackson, Publication Traffic Administrator Tracy Becker, Graphics Specialist Publisher W. Stephen Comstock

Updates/errata for this publication will be posted on the ASHRAE Web site at www.ashrae.org/publicationupdates. Errata noted in the list dated 08/6/2014 have been corrected.

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CONTENTS Preface ..........................................................................................................................viii 1

Air Handling and Psychrometrics Air Friction Chart ...................................................................................................... 1 Velocities vs. Velocity Pressures .............................................................................. 2 Noncircular Ducts..................................................................................................... 2 Fittings and Flexible Ducts ....................................................................................... 2 Duct Leakage ....................................................................................................... 3–4 Fitting Losses ........................................................................................................... 5 Circular Equivalents of Rectangular Ducts........................................................... 6–7 Flat Oval Duct Equivalents ....................................................................................... 8 Velocities for HVAC Components ............................................................................. 9 Fan Laws.......................................................................................................... 10–11 Types of Fans ................................................................................................... 12–13 Fan System Effect .................................................................................................. 14 Psychrometric Chart .............................................................................................. 15 Air-Conditioning Processes.............................................................................. 16–17 Enthalpy of Air ........................................................................................................ 18 Standard Atmospheric Data ................................................................................... 19 Moist Air Data......................................................................................................... 19 Space Air Diffusion........................................................................................... 20–21 Principles of Jet Behavior................................................................................. 22–24 Airflow Patterns of Different Diffusers .................................................................... 25 Mixed-Air Systems ................................................................................................. 26 Fully Stratified Systems.................................................................................... 31–32 Partially Mixed Systems ................................................................................... 33–34 Return Air Design................................................................................................... 35

2

Air Contaminants and Control Air Quality Standards ............................................................................................. 36 Electronic Air Cleaners........................................................................................... 37 Bioaerosols ............................................................................................................ 37 Filter Installations ................................................................................................... 37 MERV Parameters.................................................................................................. 38 Filter Application Guidelines................................................................................... 39 Indoor Contaminant Sources ........................................................................... 40–42 Gaseous Contaminants by Building Materials ................................................. 43–44 Ultraviolet Lamp Systems................................................................................. 45–46 Hood Capture Velocities......................................................................................... 47 Exhaust Duct Design and Construction ........................................................... 47–50 Contaminant Transport Velocities........................................................................... 49 Hood Entry Loss..................................................................................................... 50 Kitchen Ventilation............................................................................................ 51–53 Laboratory Hoods................................................................................................... 54 Clean Spaces......................................................................................................... 55 Airborne Particle Concentration Limits................................................................... 56

3

Water Pump Terms and Formulas .................................................................................... 57 Pump Affinity Laws................................................................................................. 57 Application of Affinity Laws .................................................................................... 58 Net Positive Suction Characteristics ................................................................ 59–60 Typical Pump Curves ............................................................................................. 61 General Information on Water ................................................................................ 62 Mass Flow and Specific Heat of Water .................................................................. 63 Freezing Points of Glycols...................................................................................... 63 Vertical Cylindrical Tank Capacity .......................................................................... 64 iii

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Horizontal Cylindrical Tank Capacity...................................................................... 64 Volume of Water in Pipe and Tube ......................................................................... 65 Water Pipe Friction Chart, Copper ......................................................................... 66 Water Pipe Friction Chart, Plastic .......................................................................... 67 Water Pipe Friction Chart, Steel............................................................................. 68 Friction Losses in Pipe Fittings ........................................................................ 69–74 4

Steam Steam Table ........................................................................................................... 75 Steam Chart........................................................................................................... 76 Steam Pipe Flow Rate ........................................................................................... 77 Steam Pipe Capacities..................................................................................... 78–79 Steam Pipe Capacities—Return Mains and Risers ............................................... 80

5

Piping Steel Pipe Data ................................................................................................ 81–83 Copper Tube Data............................................................................................ 84–86 Properties of Plastic Pipe Materials ................................................................. 87–88 Pipe, Fitting, and Valve Applications ................................................................ 89–90 Thermal Expansion of Metal Pipe .......................................................................... 91 Hanger Spacing and Rod Sizes ............................................................................. 92

6

Service Water Heating Service Water Heating System Elements .............................................................. 93 Legionella pneumophila ......................................................................................... 93 Load Diversity .................................................................................................. 94–95 Hot-Water Demand for Buildings ........................................................................... 96 Hot-Water Demand per Fixture ........................................................................ 97–99 Hot-Water Flow Rate............................................................................................ 100

7

Solar Energy Use Solar Irradiation............................................................................................ 101–102 Solar Collector Data............................................................................................. 103 Solar Heating Systems ................................................................................ 104–105

8

Refrigeration Cycles Coefficient of Performance (COP) ....................................................................... 106 Vapor Compression Cycle ........................................................................... 107–108 Absorption Refrigeration ...................................................................................... 109 Lithium Bromide Chiller Characteristics ............................................................... 110

9

Refrigerants Refrigerant Data................................................................................................... 111 Pressure-Enthalpy Chart—R-22 .......................................................................... 112 Property Tables—R-22................................................................................... 113–14 Pressure-Enthalpy Chart—R-123 ........................................................................ 115 Property Table—R-123 ........................................................................................ 116 Pressure-Enthalpy Chart—R-134a ...................................................................... 117 Property Tables—R-134a............................................................................... 118–19 Pressure-Enthalpy Chart—R-717 (Ammonia)...................................................... 120 Property Tables—R-717 (Ammonia) .................................................................... 121 Pressure Enthalpy Chart—R-404A ...................................................................... 122 Property Table—R-404A ...................................................................................... 123 Pressure Enthalpy Chart—R-407C...................................................................... 124 Property Table—R-407C...................................................................................... 125 Pressure Enthalpy Chart—R-410A ...................................................................... 126 Property Table—R-410A ...................................................................................... 127 Pressure Enthalpy Chart—R-507A ...................................................................... 128 Property Table—R-507A ...................................................................................... 129 Pressure Enthalpy Chart—R-1234yf.................................................................... 130

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Property Table—R1234yf ..................................................................................... 131 Pressure Enthalpy Chart—R-1234ze(E) .............................................................. 132 Property Table—R-1234ze(E) .............................................................................. 133 Comparative Refrigerant Performance........................................................... 134–35 Refrigerant Line Capacities—R-404A ............................................................ 136–37 Refrigerant Line Capacities—R-507A ............................................................ 138–39 Refrigerant Line Capacities—R-410A ............................................................ 140–41 Refrigerant Line Capacities—R-407C............................................................ 142–43 Refrigerant Line Capacities—R-22 ................................................................ 144–45 Refrigerant Line Capacities—R-134a ............................................................ 146–47 Oil Entrained in Suction Risers—R-22 and R-134a ....................................... 148–49 Oil Entrained in Hot-Gas Risers—R-22 and R-134a ...................................... 150–51 Refrigerant Line Capacities—Ammonia (R-717).................................................. 152 Liquid Ammonia Line Capacities.......................................................................... 153 Lubricants in Refrigerant Systems ....................................................................... 154 Secondary Coolants............................................................................................. 154 Relative Pumping Energy..................................................................................... 154 10

Refrigerant Safety Safety Group Classification .................................................................................. 155 Data and Safety Classifications for Refrigerants and Blends......................... 156–57 ASHRAE Standard 15-2010........................................................................... 158–64

11

Refrigeration Load Transmission Load ............................................................................................... 165 Product Load........................................................................................................ 166 Internal Load ........................................................................................................ 167 Infiltration Air Load ............................................................................................... 167 Equipment-Related Load ..................................................................................... 168 Safety Factor ........................................................................................................ 168 Forced-Circulation Air Coolers ............................................................................. 169

12

Air-Conditioning Load Data Cooling and Heating Loads............................................................................ 170–71 Cooling Load Check Values ................................................................................. 172 Cooling Load Computation Procedure ................................................................. 173 Heat Flow Through Building Materials ................................................................. 174 Thermal Resistance of Plane Air Spaces............................................................. 175 Surface Conductances and Resistances ............................................................ 176 Emissivity ............................................................................................................. 177 Thermal Resistance of Ventilated Attics............................................................... 178 Thermal Properties of Materials..................................................................... 179–84 CLTDs for Flat Roofs ...................................................................................... 185–86 CLTDs for Sunlit Walls.................................................................................... 187–88 Solar Cooling Load for Sunlit Glass ..................................................................... 189 Shading Coefficients for Glass ............................................................................. 190 Heat Gain from People......................................................................................... 191 Heat Gain from Lighting and LPDs ................................................................ 192–94 Heat Gain from Motors................................................................................... 195–96 Heat Gain from Restaurant Equipment ........................................................ 197–201 Heat Gain from Hospital and Laboratory Equipment ................................... 202–203 Heat Gain from Office Equipment ................................................................ 204–207 Display Fixtures Refrigerating Effect .................................................................... 207

13

Ventilation ASHRAE Standard 62.2-2010.............................................................................. 208 ASHRAE Standard 62.1-2010........................................................................ 209–11 Procedures from ASHRAE Standard 62.1-2010 ............................................ 211–20 Normative Appendix A from ASHRAE Standard 62.1-2010........................... 221–23 v

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Design Parameters for Health Care Facilities ................................................ 224–25 Operation and Maintenance................................................................................. 226 14

Energy-Conserving Design Sustainability........................................................................................................ 227 Energy Efficiency Standards................................................................................ 228 Climate Zones for United States Locations.......................................................... 229

15

Electrical Characteristics of AC Motors ............................................................................... 230 Motor Full-Load Amperes .................................................................................... 231 Useful Electrical Formulas ................................................................................... 231 Motor Controllers ................................................................................................. 232 Variable-Speed Drives (VSDs)............................................................................. 232 Photovoltaic Systems........................................................................................... 233

16

Sorbents and Desiccants Desiccant Cycle ................................................................................................... 234 Desiccant Equipment ........................................................................................... 235 Desiccant Dehumidification.................................................................................. 236 Rotary Solid Desiccant Dehumidifier Model................................................... 237–39

17

Combined Heat and Power Systems CHP Cycles.......................................................................................................... 240 Engine Sizing Tables............................................................................................ 241 Recommended Engine Maintenance................................................................... 242 Gas Engine Chiller Performance.......................................................................... 242 Engine Heat Balance ........................................................................................... 243 Energy Boundary Diagram................................................................................... 244 Heating Application Temperatures ....................................................................... 244 Mass Flows and Temperatures for Various Engines ............................................ 244 Steam Rates for Steam Turbines ......................................................................... 245 Combustion Turbines ........................................................................................... 246 Fuel Cells ....................................................................................................... 247–48

18

Fuels and Combustion Gas Pipe Sizing Table .......................................................................................... 249 Viscosity and Heating Values of Fuels ........................................................... 249–50 Liquid Fuels for Engines................................................................................. 251–52 Fuel Oil Pipe Sizing Tables .................................................................................. 252

19

Owning and Operating Maintenance Costs ........................................................................................ 253–54 Owning and Operating Cost Data ........................................................................ 255 Economic Analysis......................................................................................... 256–57

20

Sound Sound Pressure and Sound Pressure Levels ...................................................... 258 Combining Sound Levels ..................................................................................... 259 Sound Power and Sound Power Level ................................................................. 259 A- and C- Weighting............................................................................................. 259 Octave bands and 1/3 Octave Bands................................................................... 260 Design Guidance for HVAC System Noise........................................................... 261 Sound Rating Methods .................................................................................. 262–63 Sound Paths in HVAC Systems ........................................................................... 263 Silencers .............................................................................................................. 264 Outlet Configurations ........................................................................................... 264 Mechanical Equipment Noise Levels ................................................................... 265 Mechanical Equipment Sound Isolation......................................................... 265–66

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21

Vibration Single-Degree of Freedom Systems .................................................................... 267 Two-Degree of Freedom Systems ........................................................................ 267 Isolator Selection............................................................................................ 268–78

22

Evaporative Cooling Direct Evaporative Air Coolers ............................................................................. 279 Indirect Evaporative Air Coolers ..................................................................... 280–81 Multistage Evaporative Coolers............................................................................ 282 Effective Temperature Chart................................................................................. 283

23

Automatic Controls HVAC System Components ........................................................................... 284–90 HVAC Systems............................................................................................... 291–92

24

Occupant Comfort ASHRAE Standard 55-2010................................................................................. 293 Graphic Comfort Zone Method............................................................................. 293 Operative and Effective Temperature ................................................................... 293 Predicted Mean Vote ............................................................................................ 293 Air Speed to Offset Temperature.......................................................................... 294 Clothing Insulation Values.................................................................................... 295 Local Discomfort ............................................................................................ 295–96 Thermal Comfort in Naturally Ventilated Buildings............................................... 296

25

Geothermal Systems Ground-Source Heat Pumps........................................................................ 297–299 Thermal Properties of Soils and Rocks........................................................ 299–300 Ground Piping .............................................................................................. 300–302 Surface Water Piping ........................................................................................... 303

26

General System Design Criteria ................................................................................ 304–305 SI Units and Air-Conditioning Formulas ............................................................... 308 Sizing Formulas for Heating/Cooling.................................................................... 309 Cooling Tower Performance ................................................................................. 310 Thermal Storage ............................................................................................ 311–12 Cold-Air Distribution ............................................................................................. 313 Mechanical Dehumidifiers .................................................................................... 313 Heat Pipes...................................................................................................... 314–15 Air-to-Air Energy Recovery ............................................................................ 316–18 Panel Heating and Cooling............................................................................. 319–20 Variable Refrigerant Flow ............................................................................... 321–23 Units and Conversions ................................................................................... 324–25

Index.......................................................................................................................326–27

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PREFACE The ASHRAE Pocket Guide was developed to serve as a ready, offline reference for engineers without easy access to the large ASHRAE Handbook volumes. Most of the information is taken from the four volumes of the ASHRAE Handbook series, as well as from various ASHRAE Standards, and abridged or reduced to fit the smaller page size. This eighth edition, revised and expanded for 2013, includes properties for new refrigerants, new data on refrigerant safety, ventilation requirements for residential and nonresidential occupancies, occupant thermal comfort, extensive data on sound and vibration control, thermal storage, radiant-panel heating and cooling, air-to-air energy recovery, space air diffusion data, equipment heat load data, combustion turbines, fuel cells, ultraviolet lamp systems, variable refrigerant flow, and more. This edition of the ASHRAE Pocket Guide, which was first published in 1987, was compiled by ASHRAE staff editors; previous major contributors were Carl W. MacPhee, Griffith C. Burr, Jr., Harry E. Rountree, and Frederick H. Kohloss. Throughout this Pocket Guide, original sources of figures and tables are indicated where applicable. For space concerns, a shorthand for ASHRAE publications has been adopted. ASHRAE sources are noted after figure captions or table titles in brackets using the following abbreviations: Fig Tbl Ch Std 2013F, 2009F, etc 2012S, 2008S, etc. 2011A, 2007A, etc. 2010R, 2006R, etc.

Figure Table Chapter ASHRAE Standard ASHRAE Handbook—Fundamentals ASHRAE Handbook—HVAC Systems and Equipment ASHRAE Handbook—HVAC Applications ASHRAE Handbook—Refrigeration

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AIR HANDLING AND PSYCHROMETRICS

Figure 1.1

Air Handling and Psychrometrics

1.

Friction Chart for Round Duct (ρ = 0.075 lbm/ft3 and ε = 0.0003 ft) [2013F, Ch 21, Fig 10]

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Table 1.1

Velocities vs. Velocity Pressures

Velocity V, fpm 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300 2400 2500

Velocity Pressure Pv , in. H2O 0.01 0.01 0.02 0.02 0.03 0.04 0.05 0.06 0.08 0.09 0.11 0.12 0.14 0.16 0.18 0.20 0.22 0.25 0.27 0.30 0.33 0.36 0.39

Pv = (V/4005)2

Noncircular Ducts Hydraulic diameter Dh = 4A/P, where A = duct area (in.2) and P = perimeter (in.). Ducts having the same hydraulic diameter will have approximately the same fluid resistance at equal velocities.

Fittings Resistance to flow through fittings can be expressed by fitting loss coefficients C. The friction loss in a fitting in inches of water is CPv. The more radically the airflow is changed in direction or velocity, the greater the fitting loss coefficient. See ASHRAE Duct Fitting Database for a complete list. 90° mitered elbows with vanes will usually have C between 0.11 and 0.33.

Round Flexible Ducts Nonmetallic flexible ducts fully extended have friction losses approximately three times that of galvanized steel ducts. This rises rapidly for unextended ducts by a correction factor of 4 if 70% extended, 3 if 80% extended, and 2 if 90% extended. For centerline bend radius ratio to diameter of 1 to 4 the approximate loss coefficient is between 0.82 and 0.87.

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Duct Leakage Classificationa

Duct Type Metal (flexible excluded) Round and flat oval Rectangular  2 in. of water (both positive and negative pressures) > 2 and  10 in. of water (both positive and negative pressures) Flexible Metal, aluminum Nonmetal


Table 1.2

Predicted Leakage Class CL Sealedb,c Unsealedc 3

30 (6 to 70)

12

48 (12 to 110) 48 (12 to 110)c

6

8

30 (12 to 54) 30 (4 to 54)

12

Fibrous glass Round Rectangular a b

c

3 6

na na

The leakage classes listed in this table are averages based on tests conducted by AISI/ SMACNA (1972), ASHRAE/SMACNA/TIMA (1985), and Swim and Griggs (1995). The leakage classes listed in the sealed category are based on the assumptions that for metal ducts, all transverse joints, seams, and openings in the duct wall are sealed at pressures over 3 in. of water, that transverse joints and longitudinal seams are sealed at 2 and 3 in. of water, and that transverse joints are sealed below 2 in. of water. Lower leakage classes are obtained by careful selection of joints and sealing methods. Leakage classes assigned anticipate about 25 joints per 100 linear feet of duct. For systems with a high fitting to straight duct ratio, greater leakage occurs in both the sealed and unsealed conditions.

Table 1.3 Recommended Ductwork Leakage Class by Duct Type Duct Type

Leakage Class CL, cfm/100 ft2 at 1 in. of water

Metal (flexible excluded) Round Flat oval Rectangular Flexible Fibrous glass Round Rectangular

3 3 6 6 3 6

Leakage Class CL = Q/PS0.65 where Q = Ps =

leakage rate, cfm/100 ft2 surface area static pressure difference, inches of water between inside and outside of duct

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Table 1.4

Duct Sealing Requirement Levels

Duct Seal Levels Sealing Requirementsa A All transverse joints, longitudinal seams, and duct wall penetrations B All transverse joints and longitudinal seams C Transverse joints only a

Transverse joints are connections of two duct or fitting elements oriented perpendicular to flow. Longitudinal seams are joints oriented in the direction of airflow. Duct wall penetrations are openings made by screws, non-selfsealing fasteners, pipe, tubing, rods, and wire. Round and flat oval spiral lock seams need not be sealed prior to assembly, but may be coated after assembly to reduce leakage. All other connections are considered transverse joints, including but not limited to spin-ins, taps and other branch connections, access door frames, and duct connections to equipment.

Table 1.5

Duct Sealing Recommendations

Recommended Duct Seal Levels Duct Location Outdoors Unconditioned spaces Conditioned spaces (concealed ductwork) Conditioned spaces (exposed ductwork)

Table 1.6

Duct Type Supply 2 in. >2 in. Exhaust of water of water A A A B C A

A B A

B B B

Return A B C B

Duct Leakage per Unit Length

Unsealed Longitudinal Seam Leakage, Metal Ducts Type of Duct/Seam Rectangular Pittsburgh lock 26 gage 22 gage Button punch snaplock 26 gage 22 gage Round Spiral (26 gage) Snaplock Grooved

Leakage, cfm per ft Seam Length at 1 in. Water Pressure Range Average 0.01 to 0.02 0.001 to 0.002

0.0164 0.0016

0.03 to 0.15 NA (1 test) NA (1 test) 0.04 to 0.14 0.11 to 0.18

0.0795 0.0032 0.015 0.11 0.12

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Figure 1.2

At Exit, the Fitting Coefficient Co Affects ρt Loss [2013F, Ch 21, Fig 7] 5

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Lgth. Adj.b 6 8 10 12 14 16 18 20 24 28 32 36 40 44 48 52 56 60 64

3.0 4.0 5.0

Lgth. Adj.b

6 6.6 7.6 8.4 9.1 9.8 10.4 11.0 11.5 12.4 13.2 14.0 14.7 15.3 15.9 16.5 17.1 17.6 18.1

4.0 3.8 4.4 4.9

8

8.7 9.8 10.7 11.4 12.2 12.9 13.5 14.6 15.6 16.5 17.4 18.2 18.9 19.6 20.2 20.9 21.5 22.0

7

8.2 9.1 9.9 10.8 11.3 11.9 12.6 13.5 14.5 15.3 16.1 16.8 17.5 18.1 18.7 19.3 19.8 20.3

4.5 4.0 4.6 5.2

10.4 11.3 12.2 13.0 13.7 14.4 15.6 16.7 17.7 18.6 19.5 20.3 21.0 21.7 22.4 23.0 23.6

9

5.0 4.2 4.9 5.5

10.9 12.0 12.9 13.7 14.5 15.2 16.5 17.7 18.8 19.8 20.7 31.5 22.3 23.1 23.8 24.5 25.1

10

5.5 4.4 5.1 5.7

Table 1.7

12.6 13.5 14.4 15.3 16.0 17.4 18.7 19.8 20.9 21.8 22.7 23.6 24.4 25.2 25.9 26.6

11

6.0 4.6 5.3 6.0

13.1 14.2 15.1 16.0 16.8 18.3 19.6 20.8 21.9 22.9 23.9 24.8 25.7 26.5 27.3 28.0 14.7 15.7 16.7 17.5 19.1 20.5 21.8 22.9 24.0 25.0 26.0 26.9 27.7 28.6 29.3

15.3 16.4 17.3 18.2 19.9 21.3 22.7 23.9 25.0 26.1 27.1 28.0 28.9 29.8 30.6 16.9 17.9 18.9 20.6 22.1 23.5 24.8 26.0 27.1 28.2 29.2 30.1 31.0 31.9

17.5 18.5 19.5 21.3 22.9 24.4 25.7 27.0 28.1 29.2 30.3 31.2 32.2 33.1 19.1 20.1 22.0 23.7 25.2 26.6 27.9 29.1 30.2 31.3 32.3 33.3 34.3

19.7 20.7 22.7 24.4 26.0 27.4 28.8 30.0 31.2 32.3 33.4 34.4 35.4 21.3 23.3 25.1 26.7 28.2 29.6 30.9 32.2 33.3 34.4 35.5 36.5

Length of One Side of Rectangular Duct (a), in. 6.5 7.0 7.5 8.0 9.0 10.0 4.7 4.9 5.1 5.2 5.5 5.7 5.5 5.7 5.8 6.1 6.4 6.7 6.2 6.4 6.7 6.9 7.3 7.6 Length of One Side of Rectangular Duct (a), in. 12 13 14 15 16 17 18 19

21.9 34.9 25.8 27.5 29.0 30.5 31.8 33.1 34.3 35.4 36.5 37.6

20

11.0 6.0 7.0 8.0

25.1 27.1 28.9 30.5 32.1 33.5 34.9 36.2 37.4 38.5 39.6

22

12.0 6.2 7.3 8.3

26.2 28.3 30.2 32.0 33.6 35.1 36.6 37.9 39.2 40.4 41.6

24

29.5 31.5 33.3 35.1 36.7 38.2 39.6 41.0 42.3 43.5

26

28

30.6 32.7 34.6 36.4 38.1 39.7 41.2 42.7 44.0 45.3

14.0 6.6 7.8 8.9

33.9 35.9 37.8 39.5 41.2 42.8 44.3 45.7 47.1

30

15.0 6.8 8.0 9.1

Lgth. Adj.b 6 8 10 12 14 16 18 20 24 28 32 36 40 44 48 52 56 60 64

16.0 7.0 8.3 9.4


13.0 6.4 7.6 8.6

Circular Equivalents of Rectangular Duct for Equal Friction and Capacitya



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a b

32 35.0 37.1 39.0 40.9 42.6 44.3 45.8 47.3 48.7 50.1 51.4 52.7 53.9 55.1 56.3 57.4 58.4

36

39.4 41.5 43.5 45.3 47.1 48.8 50.4 51.9 53.4 54.8 56.2 57.5 58.8 60.1 61.3 62.4

34

38.2 40.3 42.2 44.0 45.7 47.3 48.9 50.4 51.8 53.2 54.5 55.8 57.0 58.2 59.3 60.5

42.6 44.7 46.6 48.4 50.2 51.9 53.5 55.0 56.5 57.9 59.3 60.6 61.9 63.1 64.3

38

43.7 45.8 47.9 49.7 51.6 53.3 54.9 56.5 58.0 59.5 60.9 62.3 63.6 64.9 66.2

40

Table based on De = 1.30 (ab)0.625/(a + b)0.25 Length of adjacent side of rectangular duct (b), in.

Lgth. Adj.b 32 36 40 44 48 52 56 60 64 68 72 76 80 84 88 92 96 48.1 49.1 51.0 52.9 54.7 56.4 58.0 59.6 61.1 62.6 64.0 65.4 66.7 68.0

42

51.4 53.4 55.4 57.3 59.1 60.8 62.5 64.1 65.7 67.2 68.7 70.1 71.5

52.5 54.6 56.6 58.6 60.4 62.2 63.9 65.6 67.2 68.7 70.2 71.7 73.1 55.7 57.8 59.8 61.7 63.6 65.3 67.0 68.7 70.3 71.8 73.3 74.8

56.8 59.0 61.0 63.0 64.9 66.7 68.4 70.1 71.7 73.3 74.9 76.3 61.2 63.4 65.4 67.4 69.3 71.1 72.9 74.6 76.3 77.9 79.4 65.6 67.7 69.8 71.8 73.7 75.4 77.3 79.1 80.8 82.4 70.0 72.1 74.2 76.2 78.1 80.0 81.8 83.5 85.3

Length of One Side of Rectangular Duct (a), in. 46 48 50 52 56 60 64

50.2 52.2 54.2 60.0 57.8 59.4 61.1 62.6 64.1 65.6 67.0 68.4 69.7

44

74.3 76.5 78.6 80.6 82.5 84.4 86.2 88.0

68

78.7 80.9 82.9 85.0 86.9 88.8 90.7

72

83.1 85.2 87.3 89.3 91.3 93.2

76

87.5 89.6 91.7 93.7 95.7

80

Circular Equivalents of Rectangular Duct for Equal Friction and Capacitya (Continued)

91.8 94.0 96.1 98.1

84

Lgth. Adj.b 32 36 40 44 48 52 56 60 64 68 72 76 80 84 96.2 88 98.4 92 100.5 96 88


Table 1.7



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8 9 11 12 15 19 22

3

7 9 10 12 13 15 18 20 21

4

8 10 — 11 13 14 18 19 21

5

8 9 — 11 12 14 15 17 19 20 23 25 28 30 33 36 39 45 52 59

6

10 — 11 13 14 16 17 — 19 21 22 24 27 30 35 39 12 — 14 15 — 17 18 20 22 23 — — — 12 — 13 15 16 — 18 19 21 24 27 30

Major Axis A, in.

14 — 16 17 — 19 22 24 —

11

14 — 15 17 18 20 21 25

12

17 19 22

14

19

16

Circular Duct Diameter, in. 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 40 42 44 46 50 58 65 71 77

8

— — — — — —

9

34 38 43 48 52 57 63 70 76

10

— — — — — — — — —

11

Table 1.8 Equivalent Flat Oval Duct Dimensions* [2013F, Ch 21, Tbl 3] Minor Axis a, in. 7 8 9 10

10 — 12 13 15 16 18 20 21 23 — — — — — — —

* Table based on De = 1.30 (ab)0.625/(a + b)0.25.

Circular Duct Diameter, in. 5 5.5 6 6.5 7 7.5 8 8.5 9 9.5 10 10.5 11 11.5 12 12.5 13 13.5 14 14.5 15 16 17 18


Major Axis A, in. 28 23 21 31 27 24 34 28 25 37 31 29 42 34 30 45 38 33 50 41 36 56 45 38 59 49 41 65 52 46 72 58 49 78 61 54 81 67 57 71 60 77 66 69 76 79 21 23 26 27 29 32 34 37 40 43 46 49 53 56 59 65 68 71 78

Minor Axis a, in. 12 14 16 18

26 29 31 34 36 39 40 44 47 51 55 58 61 64 67 77

20

35 38 39 42 46 47 50 53 57 60 69 75 82

22

37 40 41 44 46 49 52 55 62 68 74

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Table 1.9 Typical Design Velocities for HVAC Components Face Velocity, fpm

Duct Element Louvers Intake 7000 cfm and greater Less than 7000 cfm Exhaust 5000 cfm and greater Less than 5000 cfm Filters Panel filters Viscous impingement Dry-type, extended-surface Flat (low efficiency) Pleated media (intermediate efficiency) HEPA Renewable media filters Moving-curtain viscous impingement Moving-curtain dry media Electronic air cleaners Ionizing type Heating Coils Steam and hot water

400 See figure below 500 See figure below

200 to 800 Duct velocity Up to 750 250 500 200 150 to 350 500 to 1000 200 min., 1500 max.

Electric Open wire Finned tubular Dehumidifying Coils Air Washers Spray type Cell type High-velocity spray type

Refer to mfg. data Refer to mfg. data 400 to 500 Refer to mfg. data Refer to mfg. data 1200 to 1800

Louvers: Pertinent Parameters Used in Establishing Figure Parameter

Intake Parameter

Exhaust Parameter

Minimum free area (48-in. square test section), %

45

45

Water penetration, oz/(ft2/0.25 h)

Negligible (less than 0.2)

Not applicable

Maximum static pressure drop, in. of water

0.15

0.25

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Table 1.10 Fan Lawsa,b For All Fan Laws: t1 = t2 and (point of rating)1 = (point of rating)2

No.

Dependent Variables

Independent Variables

1a

Q1 = Q2

 D 1 3 N 1   -------  ------N2  D 2

1b

Press.1 = Press.2c

 D 1 2  N 1 2   -------   -------  D 2  N 2

1  -----2

1c

W1 = W2

 D 1 5  N 1 3   -------   -------  D 2  N 2

1  -----2

2a

Q1 = Q2

 D 1 2  Press.1 1/2   -------   -----------------  D 2  Press.2

  2 1/2   ------   1

2b

N1 = N2

 D 2  Press. 1 1/2   -------   -----------------  D 1  Press. 2

  2 1/2   ------   1

2c

W1 = W2

 D 1 2  Press.1 3/2   -------   -----------------  D 2  Press.2

  2 1/2   ------   1

3a

N1 = N2

 D 2 3 Q 1   -------  ------Q2  D 1



3b

Press.1 = Press.2

 D 2 4  Q 1 2   -------   -------  D 1  Q 2

1  -----2

3c

W1 = W2

 D 2 4  Q 1 3   -------   -------  D 1  Q 2

1  -----2



a. The subscript 1 denotes that the variable is for the fan under consideration. b. The subscript 2 denotes that the variable is for the tested fan. c. Ptf or Psf . Unless otherwise identified, fan performance data are based on dry air at standard conditions 14.696 psi and 70°F (0.075 lbm/ft3). In actual applications, the fan may be required to handle air or gas at some other density. The change in density may be because of temperature, composition of the gas, or altitude. As indicated by the Fan Laws, the fan performance is affected by gas density. With constant size and speed, the horsepower and pressure varies directly as the ratio of gas density to the standard air density.

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Q2 = 6000 cfm and Ptf = 1.13 in. of water 2

Using Fan Law 1a at Point E Q 1 = 6000  650  600  = 6500 cfm


The application of the Fan Laws for a change in fan speed, N, for a specific size fan is shown in Figure 1.3. The computed Pt curve is derived from the base curve. For example, point E(N1 = 650) is computed from point D(N2= 600) as follows: At D,

Using Fan Law 1b 2

P tf = 1.13   650  600  = 1.33 psi 1

The completed P tf , N = 650 curve thus may be generated by computing additional points 1 from data on the base curve, such as point G from point F.  static pressure, in. of waterhp = cfm ------------------------------------------------------------------------------fan efficiency (decimal)  6356

Figure 1.3 Example Calculation of Fan Laws [2012S, Ch 21, Fig 4]

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Table 1.11

Types of Fans [2012S, Ch 21, Tbl 1]

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2013PocketGuides.book Page 13 Tuesday, October 7, 2014 12:44 PM © 2013 ASHRAE (www.ashrae.org). For personal use only. Additional reproduction, distribution, or transmission in either print or digital form is not permitted without ASHRAE's prior written permission. Types of Fans [2012S, Ch 21, Tbl 1] (Continued)


Table 1.11

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Fan System Effect

Figure 1.4

Deficient Fan/System Performance

Figure 1.4 illustrates deficient fan/system performance. System pressure losses have been determined accurately, and a fan has been selected for operation at point 1. However, no allowance has been made for the effect of system connections to the fan on fan performance. To compensate, a fan system effect must be added to the calculated system pressure losses to determine the actual system curve. The point of intersection between the fan performance curve and the actual system curve is point 4. The actual flow volume is, therefore, deficient by the difference from 1 to 4. To achieve design flow volume, a fan system effect pressure loss equal to the pressure difference between points 1 and 2 should be added to the calculated system pressure losses, and the fan should be selected to operate at point 2. For rated performance, air must enter a fan uniformly over the inlet area in an axial direction without prerotation. Fans within plenums and cabinets or next to walls should be located so that air may flow unobstructed into the inlets.

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Figure 1.5

Psychrometric Chart for Normal Temperature, Sea Level [2013F, Ch 1, Fig 1]

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Air-Conditioning Processes

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Table 1.12 Enthalpy of Moist Air at Standard Atmospheric Pressure, 14.696 psia [2013F, Ch 1, Tbl 2, Abridged] Temp., °F –80 –70 –60 –50 –40 –30 –20 –15 –10 –5 0 5

Enthalpy, Btu/lbda –19.213 –16.804 –14.390 –11.966 –9.524 –7.052 –4.527 –3.234 –1.915 –0.561 0.835 2.286

Temp., °F 79 80 81 82 83 84 85 86 87 88 89 90

Enthalpy, Btu/lbda 42.634 43.701 44.794 45.914 47.062 48.239 49.445 50.682 51.950 53.250 54.584 55.952

10 15 20 25 30 35 40 45 50 55 60 65 70 71 72 73 74 75 76 77 78

3.803 5.403 7.106 8.934 10.916 13.009 15.232 17.653 20.306 23.229 26.467 30.070 34.097 34.959 35.841 36.744 37.668 38.615 39.584 40.576 41.593

91 92 93 94 95 96 97 98 99 100 110 120 130 140 150 160 170 180 190 200

57.355 58.795 60.272 61.787 63.343 64.939 66.578 68.260 69.987 71.761 92.386 119.615 156.077 205.828 275.493 376.736 532.269 793.142 1303.297 2688.145

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Standard Atmospheric Data for Altitudes to 30,000 ft [2013F, Ch 1, Tbl 1]

Altitude, ft –1000 –500 0 500 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000 15,000 20,000 30,000

Temperature, °F 62.6 60.8 59.0 57.2 55.4 51.9 48.3 44.7 41.2 37.6 34.0 30.5 26.9 23.4 5.5 –12.3 –47.8


Table 1.13

Pressure, psia 15.236 14.966 14.696 14.430 14.175 13.664 13.173 12.682 12.230 11.778 11.341 10.914 10.506 10.108 8.296 6.758 4.371

Source: Adapted from NASA (1976).

Table 1.14 Moisture and Air Relationships* ASHRAE has adopted pounds of moisture per pound of dry air as standard nomenclature. Relations of other units are expressed below at various dew-point temperatures. Equiv. Lb H2O/ Parts Grains/ Percent Dew Pt. °F lb dry air per million lb dry aira Moisture%b 100 0.000001 1 0.0007 –80 0.000005 5 0.0035 — –60 0.000002 21 0.148 0.13 –40 0.000008 79 0.555 0.5 20 0.00026 263 1.84 1.7 10 0.00046 461 3.22 2.9 0 0.0008 787 5.51 5.0 10 0.0013 1315 9.20 8.3 20 0.0022 2152 15.1 13.6 30 0.0032 3154 24.2 21.8 40 0.0052 5213 36.5 33.0 50 0.0077 7658 53.6 48.4 60 0.0111 11080 77.6 70.2 70 0.0158 15820 110.7 100.0 80 0.0223 22330 156.3 90 0.0312 31180 218.3 100 0.0432 43190 302.3 a. 7000 grains = 1 lb b. Compared to 70°F saturated. * NUMBERS, 1985, Altadena, CA, by Bill Holladay and Cy Otterholm. 19

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Space Air Diffusion Room air diffusion methods can be classified as one of the following: • Mixed systems produce little or no thermal stratification of air within the space. Overhead air distribution is an example of this type of system. • Fully (thermally) stratified systems produce little or no mixing of air within the occupied space. Thermal displacement ventilation is an example of this type of system. • Partially mixed systems provide some mixing within the occupied and/or process space while creating stratified conditions in the volume above. Most underfloor air distribution and task/ambient conditioning designs are examples of this type of system. • Task/ambient conditioning systems focus on conditioning only a certain portion of the space for thermal comfort and/or process control. Examples of task/ambient systems are personally controlled desk outlets (sometimes referred to as personal ventilation systems) and spot-conditioning systems. Air distribution systems, such as thermal displacement ventilation (TDV) and underfloor air distribution (UFAD), that deliver air in cooling mode at or near floor level and return air at or near ceiling level produce varying amounts of room air stratification. For floor-level supply, thermal plumes that develop over heat sources in the room play a major role in driving overall floor-toceiling air motion. The amount of stratification in the room is primarily determined by the balance between total room airflow and heat load. In practice, the actual temperature and concentration profile depends on the combined effects of various factors, but is largely driven by the characteristics of the room supply airflow and heat load configuration.

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Figure 1.6

Classification of Air Diffusion Methods [2013F, Ch 20, Fig 1] 21

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Principles of Jet Behavior Air Jet Fundamentals Air supplied to rooms through various types of outlets can be distributed by turbulent air jets (mixed and partially mixed systems) or in a low-velocity, unidirectional manner (stratified systems). If an air jet is not obstructed or affected by walls, ceiling, or other surfaces, it is considered a free jet. When outlet area is small compared to the dimensions of the space normal to the jet, the jet may be considered free as long as X  1.5 A R where X = AR =

distance from face of outlet, ft cross-sectional area of confined space normal to jet, ft2

Characteristics of the air jet in a room might be influenced by reverse flows created by the same jet entraining ambient air. If the supply air temperature is equal to the ambient room air temperature, the air jet is called an isothermal jet. A jet with an initial temperature different from the ambient air temperature is called a nonisothermal jet. The air temperature differential between supplied and ambient room air generates thermal forces (buoyancy) in jets, affecting the jet’s (1) trajectory, (2) location at which it attaches to and separates from the ceiling/floor, and (3) throw. The significance of these effects depends on the ratio between the thermal buoyancy of the air and jet momentum. Jet Expansion Zones. The full length of an air jet, in terms of the maximum or centerline velocity and temperature differential at the cross section, can be divided into four zones: • Zone 1 is a short core zone extending from the outlet face, in which the maximum velocity and temperature of the airstream remains practically unchanged. • Zone 2 is a transition zone, with its length determined by the type of outlet, aspect ratio of the outlet, initial airflow turbulence, etc. • Zone 3 is of major engineering importance because, in most cases, the jet enters the occupied area in this zone. Turbulent flow is fully established and may be 25 to 100 equivalent air outlet diameters (i.e., widths of slot air diffusers) long. • Zone 4 is a zone of jet degradation, where maximum air velocity and temperature decrease rapidly. Distance to this zone and its length depend on the velocities and turbulence characteristics of ambient air. In a few diameters or widths, air velocity becomes less than 50 fpm. Centerline Velocities in Zones 1 and 2. In zone 1, the ratio Vx /Vo is constant and ranges between 1.0 and 1.2, equal to the ratio of the center velocity of the jet at the start of expansion to the average velocity. The ratio Vx /Vo varies from approximately 1.0 for rounded entrance nozzles to about 1.2 for straight pipe discharges; it has much higher values for diverging discharge outlets. Experimental evidence indicates that, in zone 2, V -----x- = Vo

Kc Ho ------------X

where Vx = Vo =

centerline velocity at distance X from outlet, fpm Vc /Cd Rfa = average initial velocity at discharge from open-ended duct or across contracted stream at vena contracta of orifice or multiple-opening outlet, fpm Vc = nominal velocity of discharge based on core area, fpm Cd = discharge coefficient (usually between 0.65 and 0.90) ratio of free area to gross (core) area Rfa = width of jet at outlet or at vena contracta, ft Ho = centerline velocity constant, depending on outlet type and discharge pattern (see = Kc Table 1.15) X  (1/KcHo )1/2 = distance from outlet to measurement of centerline velocity Vx, ft Centerline Velocity in Zone 3. In zone 3, maximum or centerline velocities of radial and axial isothermal jets can be determined accurately from the following equations: 22

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Outlet Type High sidewall grilles High sidewall linear Low sidewall Baseboard Floor grille Ceiling Ceiling linear slot a Free b

Discharge Pattern 0° deflectiona Wide deflection Core less than 4 in. highb Core more than 4 in. high Up and on wall, no spread Wide spreadb Up and on wall, no spread Wide spread No spreadb Wide spread 360° horizontalc Four-way; little spread One-way; horizontal along ceilingb

area is about 80% of core area. Free area is about 50% of core area.

c

Ao Free Free Free Free Free Free Core Core Free Free Neck Neck Free

Kc 5.7 4.2 4.4 5.0 4.5 3.0 4.0 2.0 4.7 1.6 1.1 3.8 5.5


Table 1.15 Recommended Values for Centerline Velocity Constant Kc for Commercial Supply Outlets for Fully and Partially Mixed Systems, Except UFAD [2013F, Ch 20, Tbl 1]

Cone free area is greater than duct area.

K c Vo A o Kc Qo V x = ----------------------- = ------------X X Ao where Kc = Ao = Ac Qo

= =

centerline velocity constant free area, core area, or neck area as shown in Table 1.14 (obtained from outlet manufacturer), ft2 measured gross (core) area of outlet, ft2 discharge from outlet, cfm

Because Ao equals the effective area of the stream, the flow area for commercial registers and diffusers, according to ASHRAE Standard 70, can be used in the equation above with the appropriate value of Kc. Throw. The previous equation can be transposed to determine the throw X of an outlet if the discharge volume and the centerline velocity are known: Kc Qo X = ---------------Vx Ao

Comparison of Free Jet to Attached Jet Most manufacturers’ throw data obtained in accordance with ASHRAE Standard 70 assume the discharge is attached to a surface. An attached jet induces air along the exposed side of the jet, whereas a free jet can induce air on all its surfaces. Because a free jet’s induction rate is larger compared to that of an attached jet, a free jet’s throw distance will be shorter. To calculate the throw distance X for a noncircular free jet from catalog data for an attached jet, the following estimate can be used. Xfree = Xattached × 0.707 Circular free jets generally have longer throws compared to noncircular jets. Jets from ceiling diffusers initially tend to attach to the ceiling surface, because of the force exerted by the Coanda effect. However, cold air jets will detach from the ceiling if the airstream’s buoyancy forces are greater than the inertia of the moving air stream. 23

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Figure 1.7 Chart for Determining Centerline Velocities of Axial and Radial Jets [2013F, Ch 20, Fig 3]

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01_AirHandling&Psychro.fm Page 25 Tuesday, October 7, 2014 3:34 PM © 2013 ASHRAE (www.ashrae.org). For personal use only. Additional reproduction, distribution, or transmission in either print or digital form is not permitted without ASHRAE's prior written permission.


Figure 1.8

Airflow Patterns of Different Diffusers

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System Design Mixed Air Distribution In mixed air systems, high-velocity supply jets from air outlets maintain comfort by mixing room air with supply air. This air mixing, heat transfer, and resultant velocity reduction should occur outside the occupied zone. Occupant comfort is maintained not directly by motion of air from outlets, but from secondary air motion from mixing in the unoccupied zone. Comfort is maximized when uniform temperature distribution and room air velocities of less than 50 fpm are maintained in the occupied zone. Maintaining velocities less than 50 fpm in the occupied zone is often overlooked by designers, but is critical to maintaining comfort. The outlet’s selection, location, supply air volume, discharge velocity, and air temperature differential determine the resulting air motion in the occupied zone. Principles of Operation Mixed systems generally provide comfort by entraining room air into discharge jets located outside occupied zones, mixing supply and room air. Ideally, these systems generate low-velocity air motion (less than 50 fpm) throughout the occupied zone to provide uniform temperature gradients and velocities. Proper selection of an air outlet is critical for proper air distribution; improper selection can result in room air stagnation, unacceptable temperature gradients, and unacceptable velocities in the occupied zone that may lead to occupant discomfort. The location of a discharge jet relative to surrounding surfaces is important. Discharge jets attach to parallel surfaces, given sufficient velocity and proximity. When a jet is attached, the throw increases by about 40% over a jet discharged in an open area. This difference is important when selecting an air outlet. For detailed discussion of the surface effect on discharge jets, see Chapter 20 of the 2013 ASHRAE Handbook—Fundamentals. Mixed air systems typically use either ceiling or sidewall outlets discharging air horizontally, or floor- or sill-mounted outlets discharging air vertically. They are the most common method of air distribution in North America. Horizontal Discharge Cooling with Ceiling-Mounted Outlets Ceiling-mounted outlets typically use the surface effect to transport supply air in the unoccupied zone. The supply air projects across the ceiling and, with sufficient velocity, can continue down wall surfaces and across floors. In this application, supply air should remain outside the occupied zone until it is adequately mixed and tempered with room air. Overhead outlets may also be installed on exposed ducts, in which case the surface effect does not apply. Typically, if the outlet is mounted 1 ft or more below a ceiling surface, discharge air will not attach to the surface. The unattached supply air has a shorter throw and can project downward, resulting in high air velocities in the occupied zone. Some outlets are designed for use in exposed duct applications. Typical outlet performance data presented by manufacturers are for outlets with surface effect; consult manufacturers for information on exposed duct applications.

Figure 1.9 Air Supplied at Ceiling Induces Room Air into Supply Jet [2011A, Ch 57, Fig 2] 26

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Vertically projected outlets are typically selected for high-ceiling applications that require forcing supply air down to the occupied zone. It is important to keep cooling supply air velocity below 50 fpm in the occupied zone. For heating, supply air should reach the floor. There are outlets specifically designed for vertical projection and it is important to review the manufacturer’s performance data notes to understand how to apply catalog data. Throws for heating and cooling differ and also vary depending on the difference between supply and room air temperatures. Cooling with Sidewall Outlets Sidewall outlets are usually selected when access to the ceiling plenum is restricted. Sidewall outlets within 1 ft of a ceiling and set for horizontal or a slightly upward projection the sidewall outlet provide a discharge pattern that attaches to the ceiling and travels in the unoccupied zone. This pattern entrains air from the occupied zone to provide mixing. In some applications, the outlet must be located 2 to 4 ft below the ceiling. When set for horizontal projection, the discharge at some distance from the outlet may drop into the occupied zone. Most devices used for sidewall application can be adjusted to project the air pattern upwards toward the ceiling. This allows the discharge air to attach to the ceiling, increasing throw distance and minimizing drop. This application provides occupant comfort by inducing air from the occupied zone into the supply air. Some outlets may be more than 4 ft below the ceiling (e.g., in high-ceiling applications, the outlet may be located closer to the occupied zone to minimize the volume of the conditioned space). Most devices used for sidewall applications can be adjusted to project the air pattern upward or downward, which allows the device’s throw distance to be adjusted to maximize performance. When selecting sidewall outlets, it is important to understand the manufacturer’s data. Most manufacturers offer data for outlets tested with surface effect, so they only apply if the device is set to direct supply air toward the ceiling. When the device is 4 ft or more below a ceiling, or supply air is directed horizontally or downward, the actual throw distance of the device is typically shorter. Many sidewall outlets can be adjusted to change the spread of supply air, which can significantly change throw distance. Manufacturers usually publish throw distances based on specific spread angles.


Vertical-Discharge Cooling or Heating with Ceiling-Mounted Outlets

Cooling with Floor-Mounted Air Outlets Although not typically selected for nonresidential buildings, floor-mounted outlets can be used for mixed system cooling applications. In this configuration, room air from the occupied zone is induced into the supply air, providing mixing. When cooling, the device should be selected to discharge vertically along windows, walls, or other vertical surfaces. Typical nonresidential applications include lobbies, long corridors, and houses of worship. It is important to select a device that is specially designed for floor applications. It must be able to withstand both the required dynamic and static structural loads (e.g., people walking on them, loaded carts rolling across them). Also, many manufacturers offer devices designed to reduce the possibility of objects falling into the device. It is strongly recommended that obstructions are not located above these in-floor air terminals, to avoid restricting their air jets. Long floor-mounted grilles generally have both functioning and nonfunctioning segments. When selecting air outlets for floor mounting, it is important to note that the throw distance and sound generated depend on the length of the active section. Most manufacturers’ catalog data include correction factors for length’s effects on both throw and sound. These corrections can be significant and should be evaluated. Understanding manufacturers’ performance data and corresponding notes is imperative. Cooling with Sill-Mounted Air Outlets Sill-mounted air outlets are commonly used in applications that include unit ventilators and fan coil units. The outlet should be selected to discharge vertically along windows, walls, or other vertical surfaces, and project supply air above the occupied zone. As with floor-mounted grilles, when selecting and locating sill grilles, consider selecting devices designed to reduce the nuisance of objects falling inside them. It is also recommended that sills be designed to prevent them from being used as shelves. 27

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Heating and Cooling with Perimeter Ceiling-Mounted Outlets When air outlets are used at the perimeter with vertical projection for heating and/or cooling, they should be located near the perimeter surface, and selected so that the published 150 fpm isothermal throw extends at least halfway down the surface or 5 ft above the floor, whichever is lower. In this manner, during heating, warm air mixes with the cool downdraft on the perimeter surface, to reduce or even eliminate drafts in the occupied space. If a ceiling-mounted air outlet is located away from the perimeter wall, in cooling mode, the high-velocity cool air reduces or overcomes the thermal updrafts on the perimeter surface. To accomplish this, the outlet should be selected for horizontal discharge toward the wall. Outlet selection should be such that isothermal throw to the terminal velocity of 150 fpm should include the distance from the outlet to the perimeter surface. For heating, the supply air temperature should not exceed 15°F above the room air temperature. Space Temperature Gradients and Airflow Rates A fully mixed system creates homogeneous thermal conditions throughout the space. As such, thermal gradients should not be expected to exist in the occupied zone. Improper selection, sizing, or placement may prevent full mixing and can result in stagnant areas, or having highvelocity air entering the occupied zone. Supply airflow requirements to satisfy space sensible heat gains or losses are inversely proportional to the temperature difference between supply and return air. The following equation can be used to calculate space airflow requirements (at standard conditions): qs Q = ---------------------------1.08  t r – t s  where Q qs tr ts

= = = =

required supply airflow rate to meet sensible load, cfm net sensible heat gain in the space, Btu/h return or exhaust air temperature, °F supply air temperature, °F

For fully mixed systems with conventional ceiling heights, the return (or exhaust) and room air temperatures are the same; for example, a room with a set-point temperature of 75°F has, on average, a 75°F return or exhaust air temperature.

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Standards for Satisfactory Air Diffusion

Figure 1.10 Percentage of Occupants Objecting to Drafts in Air-Conditioned Rooms

The object of air diffusion in warm-air heating, ventilating, and air-conditioning systems is to create the proper combination of temperature, humidity, and air motion in the occupied zone of the conditioned room—from the floor to 6 ft above floor level. Discomfort can arise due to any of the following: excessive air motion (draft), excessive room air temperature variations (horizontal, vertical, or both), failure to deliver or distribute air according to the load requirements at different locations, overly rapid fluctuation of room temperature.

Air Diffusion Performance Index (ADPI) ADPI is the percentage of locations where measurements are taken that meet these specifications for effective draft temperature and air velocity. If the ADPI is maximum (approaching 100%), the most desirable conditions are achieved. ADPI should be used only for cooling mode in sedentary occupancies. Where air doesn’t strike a wall but collides with air from a neighboring diffuser, L is one-half the distance between the diffusers plus the distance the mixed air drops to the occupied zone. Table 1.16 Characteristic Room Length for Several Diffusers Diffuser Type High sidewall grille Circular ceiling pattern diffuser Sill grille Ceiling slot diffuser Light troffer diffusers Cross-flow pattern ceiling diffusers

Characteristic Length L Distance to wall perpendicular to jet Distance to closest wall or intersecting air jet Length of room in direction of jet flow Distance to wall or midplane between outlets Distance to midplane between outlets plus distance from ceiling to top of occupied zone Distance to wall or midplane between outlets

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Table 1.17 Air Diffusion Performance Index (ADPI) Selection Guide Terminal Device

High sidewall grilles

Circular ceiling diffusers

Sill grille, straight vanes

Sill grille, spread vanes

Ceiling slot diffusers (for T100/L) Light troffer diffusers Cross-flow pattern diffusers

Room Load, Btu/h·ft2 80 60 40 20 <10 80 60 40 20 <10 80 60 40 20 80 60 40 20 80 60 40 20 60 40 20 11 to 50 11 to 50

X50 /L for Maximum ADPI 1.8 1.8 1.6 1.5 1.4 0.8 0.8 0.8 0.8 0.8 1.7 1.7 1.3 0.9 0.7 0.7 0.7 0.7 0.3 0.3 0.3 0.3 2.5 1.0 1.0 2.0 2.0

Maximum ADPI

For ADPI Greater than

Range of X50/L

68 72 78 85 90 76 83 88 93 99 61 72 86 95 94 94 94 94 85 88 91 92 86 92 95 96 96

— 70 70 80 80 70 80 80 80 80 60 70 80 90 90 80 — — 80 80 80 80 80 90 90 90 80

— 1.5 to 2.2 1.2 to 2.3 1.0 to 1.9 0.7 to 2.1 0.7 to 1.3 0.7 to 1.2 0.5 to 1.5 0.4 to 1.7 0.4 to 1.7 1.5 to 1.7 1.4 to 1.7 1.2 to 1.8 0.8 to 1.3 0.6 to 1.5 0.6 to 1.7 — — 0.3 to 0.7 0.3 to 0.8 0.3 to 1.1 0.3 to 1.5 <3.8 <3.0 <4.5 1.4 to 2.7 1.0 to 3.4

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Systems that discharge cool air at low sidewall or floor locations with very little entrainment of (and thus mixing with) room air create (vertical) thermal stratification throughout the space. These displacement ventilation systems have been popular in northern Europe for some time. Floor-based outlets in underfloor applications may also be used to provide fully stratified air distribution. Principles of Operation Thermal displacement ventilation (TDV) systems (see Figure 1.11) use very low discharge velocities, typically 50 to 70 fpm, to deliver cool supply air to the space. The discharge temperature of the supply air is generally above 60°F, although lower temperatures may be used in industrial applications, exercise or sports facilities, and transient areas. The cool air is negatively buoyant compared to ambient air and drops to the floor after discharge. It then spreads across the lower level of the space. As convective heat sources (see Figure 1.11) in the space transfer heat to the cooler air around them, natural convection currents form and rise along the heat transfer boundary. Without significant room air movement, these currents rise to form a convective heat plume around and above the heat source. As the plume rises, it expands by entraining surrounding air. Its growth and ascent are proportional to the heat source’s size and intensity and temperature of ambient air above it. Ambient air from below and around the heat source fills the void created by the rising plume. If the heat source is near the floor (e.g., an occupant), the plume entrains cool, conditioned air from the floor level, which is drawn to the respiration level, and serves as the source of inhaled air. Exhaled air rises with the escaping heat plume, because it is warmer and more humid than the ambient air. Convective heat from sources located above the occupied zone has little effect on occupied-zone air temperature. At a certain height, where plume temperature equals ambient temperature, the plume disintegrates and spills horizontally. Two distinct zones are thus formed in the room: a lower occupied zone with little or no recirculation flow (close to displacement flow), and an upper zone with recirculation flow. The boundary between these two zones is called shift zone. The shift zone height is calculated as the height above the floor where the total amount of air carried in convective plumes above heat sources equals the supply airflow distributed through displacement diffusers. Actual and simplified representations of the temperature gradient in the space are shown in Figure 1.12.


Fully Stratified Air Distribution

Outlet Characteristics Displacement outlets are designed for average face velocities between 50 and 70 fpm, and are typically in a low sidewall or floor location. Return or exhaust air intakes should always be located above the occupied zone for human thermal comfort applications. Displacement outlets are available in a number of configurations and sizes. Some models are designed to fit in corners or along sidewalls, or stand freely as columns. It is important to consider the degree of flow equalization the outlet achieves, because use of the entire outlet surface for air

Figure 1.11 Displacement Ventilation System Characteristics [2011A, Ch 57, Fig 3] 31

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Figure 1.12

Temperature Profile of Displacement Ventilation [2011A, Ch 57, Fig 4]

discharge is paramount to minimizing clear zones and maintaining acceptable temperatures at the lower levels of the space. Stationary occupants should not be subjected to discharge velocities exceeding about 40 fpm because air at the ankle level within this velocity envelope tends to be quite cool. As such, most outlet manufacturers define a clear zone in which location of stationary, low-activity occupants is strongly discouraged, but transient occupancy, such as in corridors or aisles, is possible. Occupants with high activity levels may also find the clear zone acceptable. Unlike mixed systems, outlets in thermal displacement systems discharge air at very low velocities, resulting in very little mixing. As such, design of these systems primarily involves determining a supply airflow rate to manage the thermal gradients in the space in accordance with ASHRAE comfort guidelines. ASHRAE Standard 55 recommends that the vertical temperature difference between the ankle and head levels of space occupants be limited to no more than 5.4°F to maintain a high degree (>95%) of occupant satisfaction. Application Considerations Displacement ventilation is a cooling-only method of room air distribution. For heating, a separate system is generally recommended. Displacement ventilation can be used successfully in combination with radiators and convectors installed at the exterior walls to offset space heat losses. Radiant heating panels and heated floors also can also be used with displacement ventilation. To maintain displacement ventilation, outlets should supply ventilation air about 4°F lower than the desired room temperature. Thermal displacement ventilation systems can be either constant or variable air volume. A thermostat in a representative location in the space or return plenum should determine the delivered air volume or temperature. If the time-averaged requirements of ASHRAE Standard 62.12004 are met, intermittent on/off airflow control can be used. Avoid using thermal displacement and mixed air systems in the same space, because mixing destroys the natural stratification that drives the thermal displacement ventilation system. Thermal displacement systems can be complemented by hydronic systems such as chilled floors. Use caution when combining chilled ceilings, beams, or panels with fully stratified systems, because cold surfaces in the upper zone of the space may recirculate contaminants stratified in the upper zone back into the occupied zone.

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A partially mixed system’s characteristics fall between a fully mixed system and a fully stratified system. It includes both a high-velocity mixed air zone and a low-velocity stratified zone where room air motion is caused by thermal forces. For example, floor-based outlets, when operating in a cooling mode with relatively high discharge velocities (>150 fpm), create mixing, thus affecting the amount of stratification in the lower portions of the room. In the upper portions of the room, away from the influence of floor outlets, room air often remains thermally stratified in much the same way as displacement ventilation systems. Principles of Operation Supply air is discharged, usually vertically, at relatively high velocities and entrains room air in a similar fashion to outlets used in mixed air systems. This entrainment, as shown in Figure 1.13 reduces the temperature and velocity differentials between supply and ambient room air. This discharge results in a vertical plume that rises until its velocity is reduced to about 50 fpm. At this point, its kinetic energy is insufficient to entrain much more room air, so mixing stops. Because air in the plume is still cooler than the surrounding air, the supply air spreads horizontally across the space, where it is entrained by rising thermal plumes generated by nearby heat sources. Research and experience have shown that the amount of room air stratification varies depending on design, commissioning, and operation. Control of stratification includes the following considerations: • By reducing airflow and mixing in the occupied zone, fan energy can be reduced and stratification can be increased, approaching a reasonable target at 3°F to 4°F temperature difference from head to ankle height, which satisfies ASHRAE Standard 55-2010. • By increasing airflow and mixing in the occupied zone, excessive stratification can be avoided, thereby improving thermal comfort.


Partially Mixed Air Distribution

Figure 1.13 shows one example of the resulting room air distribution in which the room air is mixed in the lower mixed zone, which is bounded by the floor and the elevation (throw height) at which the 50 fpm terminal velocity occurs. At this elevation, stratification begins to occur and a linear temperature gradient, similar to that found in thermal displacement systems, forms and extends through the stratified zone. As with thermal displacement ventilation, convective heat plumes from space heat sources draw conditioned air from the lower (mixed) level through the stratified zone and to the overhead return location. A third zone, referred to as the upper mixed zone, may exist where the volume of rising heat plumes terminate. Although velocities in this area are quite low, the air tends to be mixed.

Figure 1.13 UFAD System in Partially Stratified Application [2011A, Ch 57, Fig 6]

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Outlet Characteristics One outlet type is a swirl diffuser with a high-induction core, which induces large amounts of room air to quickly reduce supply to ambient air velocity and temperature differentials. Supply air is injected into the room as a swirling vertical plume close to the outlet. Properly selected, these outlets produce a limited vertical projection of the supply air plume, restricting mixing to the lower portions of the space. Most of these outlets allow occupants to adjust the outlet airflow rate easily. Other versions incorporate automatically controlled dampers that are repositioned by a signal from the space thermostat and/or central control system. Another category includes more conventional floor grilles designed for directional discharge of supplied airflow. These grilles may be either linear or modular in design, and may allow occupants to adjust the discharge air pattern by repositioning the core of the outlet. Most floor grilles include an integral actuated damper, or other means, that automatically throttles the volume of air in response to the zone conditioning requirements. Room air induction allows UFAD diffusers to comfortably deliver supply air a few degrees cooler than possible with outlets used for thermal displacement ventilation outlets. The observance of clear, or adjacent, zones above and around the diffusers, where stationary occupants should not reside, is recommended. Outlet manufacturers typically identify such restrictive areas in their product literature. As for thermal displacement systems, design involves determining a supply airflow rate that limits thermal gradients in the occupied zone in accordance with ASHRAE Standard 55 guidelines. ASHRAE Standard 55 recommends that the vertical temperature difference between the ankle and head level of space occupants be limited to no more than 5.4°F if a high degree (>95%) of occupant comfort is to be maintained. Application Considerations Some considerations include the following: • Supply temperatures in the access floor cavity should be kept at 60°F or above, to minimize the risk of condensation and subsequent mold growth. • Most UFAD outlets can be adjusted automatically by a space thermostat or other control system, or manually by the occupant. In the latter case, outlets should be located within the workstation they serve. • Use of manually adjusted outlets should be restricted to open office areas where cooling loads do not tend to vary considerably or frequently. Perimeter areas and conference rooms require automatic control of supply air temperatures and/or flow rates because their thermal loads are highly transient. • Heat transfer to and from the floor slab affects discharge air temperature and should be considered when calculating space airflow requirements. Floor plenums should be well sealed to minimize air leakage, and exterior walls should be well insulated and have good vapor retarders. Night and holiday temperature setbacks should likely be avoided, or at least reduced, to minimize plenum condensation and thermal mass effect problems. With air-side economizers, using enthalpy control rather than dry-bulb control can help reduce hours of admitting high moisture-content air, thus also reducing the potential for condensation in the floor plenums. • Avoid using stratified and mixed air systems in the same space, because mixing destroys the natural stratification that drives the stratified system. • Return static pressure drop should be relatively equal throughout the spaces being served by a common UFAD plenum. This reduces the chance of unequal pressurization in the UFAD plenum.

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The success of a mixed air distribution system depends primarily on supply diffuser location. Return grille location is far less critical than with outlets. In fact, the return air intake affects room air motion only immediately around the grille. Measurements of velocity near a return air grille show a rapid decrease in magnitude as the measuring device is moved away from the grille face. Table 1.18 shows recommended maximum return air grille velocities as a function of grille location. Every enclosed space should have return/transfer inlets of adequate size per this table. For stratified and partially mixed air distribution systems, there are advantageous locations for return air inlets. For example, an intake can be located to return the warmest air in cooling season. If the outlet is selected to provide adequate throw and directed away from returns or exhausts, supply short-circuiting is normally not a problem. The success of this practice is confirmed by the availability and use of combination supply and return diffusers.


Return Air Inlets

Table 1.18 Recommended Return Inlet Face Velocities [2011A, Ch 57, Tbl 1] Inlet Location Above occupied zone In occupied zone, not near seats In occupied zone, near seats Door or wall louvers Through undercut area of doors

Velocity Across Gross Area, fpm >800 600 to 800 400 to 600 200 to 300 200 to 300

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2.

AIR CONTAMINANTS AND CONTROL

Air Contaminants and Control

Table 2.1 National Ambient Air Quality Standards for the United States [2013F, Ch 11, Tbl 12] Contaminant

Primary or Secondary Standard

Carbon monoxide

Primary

Nitrogen dioxide

Primary Primary/ secondary

Ozone

Averaging Time

Level

Details

1h 8h 1h

35 ppm 9 ppm 100 ppb

Not to be exceeded more than once per year 98th percentile, averaged over 3 years

1 yr

53 ppb

Annual mean

Primary/ secondary

8h

75 ppb

Primary

1h

75 ppb

Sulfur dioxide Particulate, PM2.5a Particulate, PM10b Lead (Pb) in particles

Annual fourth-highest daily maximum 8 h concentration, averaged over 3 years 99th percentile of 1 h daily maximum concentrations, averaged over 3 years Not to be exceeded more than once per year 98th percentile, averaged over 3 years Annual mean, averaged over 3 years Not to be exceeded more than once per year on average over 3 years

Secondary

3h

500 ppb

Primary/ secondary Primary/ secondary Primary/ secondary

24 h 1 yr

35 µg/m3 15 µg/m3

24 h

150 µg/m3

3 mo

0.15 µg/m3 Not to be exceeded

aPM 2.5 = particulates below 2.5 µm diameter. b PM10 = particulates below 10 µm diameter. 9

ppb = parts per 10 Source: National Ambient Air Quality Standards (NAAQS), U.S. Environmental Protection Agency, Washington, DC, 2012.

Figure 2.1 Particle Size Distribution of Atmospheric Dust 36

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Electronic Air Cleaners

Bioaerosols Bioaerosols, particulates of biological origin, are of concern in indoor air due to their association with allergies and asthma and their ability to cause disease. Airborne viral and bacterial aerosols are generally transmitted by droplet nuclei, averaging about 3 m in diameter. Fungal spores range between 2 m and 5 m. Fifty to seventy percent dust spot efficiency filters can remove most microbial agents 1 m to 2 m in diameter. Sixty percent dust spot efficiency filters can remove 85% or more of 2.5 m particles; while 85% filters can remove about 96%.


Electronic air cleaners use electrostatic precipitation to remove and collect particulate contaminants such as dust, smoke, and pollen. Wires with a positive direct current potential of between 6 and 25 kV DC are suspended equidistant between grounded plates, creating an ionizing field for charging particles. The collecting plate section consists of parallel plates with a positive voltage of 4 to 10 kV (dc) applied to alternate plates. Plates that are not charged are at ground potential. As particles pass into this section, they are forced to the plates by the electric field on the charges they carry, and thus are removed from the airstream and collected by the plates. Electronic air cleaners typically operate from a 120- or 240-V AC single-phase electrical service. Power consumption ranges from 20 to 40 watts per 1000 cfm of capacity. This type of air filter can remove and collect airborne contaminants with average efficiencies of up to 98% at low airflow velocities (150 to 350 fpm) when tested per ASHRAE Standard 52.1. Efficiency decreases (1) as the collecting plates become loaded with particulates, (2) with higher velocities, or (3) with nonuniform velocity. As with most air filtration devices, the duct approaches to and from the air cleaner housing should be arranged so that the airflow is distributed uniformly over the face area. Panel prefilters should also be used to help distribute the airflow and to trap large particles that might short out or cause excessive arcing within the high-voltage section.

Filter Installation Efficiency is sharply reduced if air leaks through poorly designed or installed frames. Install filters with face area at right angles to air flow whenever possible. Install high-efficiency filters as close as possible to the room to minimize pickup of particles between filter and outlet. Provide at least 20 in. access in front of or behind filters, or both.

ASHRAE Air Filtration Standards ASHRAE Standard 52.1 (withdrawn in 2009) contained a test procedure for measuring the weight of a synthetic dust captured by a filter (arrestance). This gives a standard for comparing ability of fibers to remove coarse particles. ASHRAE Standard 52.2 contains the test procedure for comparing filter removal efficiency by particle size. For more efficient filters, arrestance is essentially 100% efficient, and their efficiency in removing smaller particles is tested. The dust spot efficiency of Standard 52.1 is replaced by the Standard 52.2 tests and classification.

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Table 2.2 Standard 52.2 Minimum Efficiency Reporting Value (MERV) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Filter Minimum Efficiency Reporting Value (MERV) Parameters Composite Average Particle Size Efficiency, % in Size Range, m Range 1 0.30–1.0 n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a

Range 2 1.0–3.0

Range 3 3.0–10.0

n/a E3 < 20 n/a E3 < 20 n/a E3 < 20 n/a E3 < 20 n/a 20 E3 < 35 n/a 35 E3 < 50 n/a 50 E3 < 70 n/a 70 E3 E2 < 50 85 E3 50 E2 < 65 85 E3

n/a 65 E2 < 80 n/a 80 E2 E1 < 75 90 E2 75 E1 < 85 90 E2 85 E1 < 95 90 E2 95 E1 95 E2

85 E3 90 E3 90 E3 90 E3 90 E3 95 E3

Average Arrestance,%, by Standard 52.1 Method

Minimum Final Resistance

Pa

in. of water

Aavg < 65 65 Aavg < 70 70 Aavg < 75 75 Aavg n/a n/a n/a n/a n/a n/a

75 75 75 75 150 150 150 150 250 250

0.3 0.3 0.3 0.3 0.6 0.6 0.6 0.6 1.0 1.0

n/a n/a n/a n/a n/a n/a

250 250 350 350 350 350

1.0 1.0 1.4 1.4 1.4 1.4

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MERV 4 MERV 3 MERV 2 MERV 1

MERV 5

MERV 8 MERV 7 MERV 6

MERV 9

MERV 12 MERV 11 MERV 10

MERV 14

MERV 16 MERV 15

MERV 17

MERV 18

MERV 19

MERV 20

Standard 52.2 MERV

<20% <20% <20% <20%

Intended to replace 20 to 60% dust-spot efficiency filters



N/A

Intended Standard 52.1 Value

>70% >70% >65% <65%

>85%

>90% >90% >85%

>90%

>97% >95% >95%

>98%

>99% >99%

Wide range of pleated media, ring panels, cubes, pockets in synthetic or fiberglass, disposable panels, depths from 1 to 24 in.

Box-style wet-laid or lofted fiberglass, boxstyle synthetic media, minipleated synthetic or fiberglass paper, depths from 2 to 12 in. Pocket filters either rigid or flexible in synthetic or fiberglass, depths from 12 to 36 in.

Box-style wet-laid or lofted fiberglass, boxstyle synthetic media, minipleated synthetic or fiberglass paper, depths from 4 to 12 in., Pocket filters of fiberglass or synthetic media 12 to 36 in.

SULPA >99.999% 0.1 to 0.2 m IEST type F (ceiling panel) ULPA >99.999% 0.3 m IEST type D (ceiling panel) HEPA > 99.99% 0.3 m IEST type C (ceiling or up to 12 in. deep) HEPA > 99.97% 0.3 m IEST type A (box style 6 to 12 in. deep)

Sample Air Cleaner Type(s)

Protection from blowing large particle dirt and debris, industrial environment Inertial separators ventilation air

General HVAC filtration, industrial equipment filtration, commercial property, schools, prefilter to highefficiency filters, paint booth intakes, electrical/phone equipment protection

3.0 to 10 m size range: pollens, earth-origin dust, mold spores, cement dust, powdered milk, snuff, hair spray mist Arrestance method

Food processing facilities, air separation plants, commercial buildings, better residential, industrial air cleaning, prefiltration to higherefficiency filters, schools, gymnasiums

Day surgery, general surgery, hospital general ventilation, turbo equipment, compressors, welding/soldering air cleaners, prefilters to HEPAs, LEED for existing (EB) and new (NC) commercial buildings, smoking lounges

1.0 to 3.0 m size range: milled flour, lead dust, combustion soot, Legionella, coal dust, some bacteria, process grinding dust

0.3 to 1.0 m size range: bacteria, smoke (ETS), paint pigments, face powder, some virus, droplet nuclei, insecticide dusts, soldering fumes

Cleanroom, pharmaceutical 0.12 to 0.5 m particles: manufacturing and exhaust, radioactive virus (unattached), carbon material handling and exhaust, dust, sea salt, radon progeny, orthopedic and organ transplant surgery, combustion smoke carcinogenic materials, welding fumes

Example Applications

Table 2.3 Filter Application Guidelines [2012S, Ch 29, Tbl 2] Arrestance Example Range of Value Contaminants Controlled


Note: MERV for non-HEPA/ULPA filters also includes test airflow rate, but it is not shown here because it is of no significance for the purposes of this table. N/A = not applicable.

E-3 Range

E-2 Range

E-1 Range

HEPA Filters



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Contaminant

Carbon monoxide

ppma

0.5 to 5 ppma (without gas stoves) 5 to 15 ppma (with gas stoves)

Heating system

Sulfur dioxide

Sources: aEPA (2011) bNRC (1981)

Ozone

Biological contaminants

Radon and progeny Carbon dioxide

Formaldehyde

Combustion, gas stoves, water heaters, gasfired dryers, cigarettes, engines

Nitrogen dioxide

cSeppänen et al. (1999) dWeschler (2000)

ppma

42 ppbd

NA

1.3 pCi/La 600 to 1000 ppmc

0.1 to 0.3

and ASHRAE Standard 62.1, Appendix C

Insulation, product binders, pressed wood products, carpets Building materials, groundwater, soil Combustion appliances, humans, pets Humans, pets, rodents, insects, plants, fungi, humidifiers, air conditioners Electric arcing, electronic air cleaners, copiers, printers

Different for each VOCc (2 to 5 times outdoor levels)

Combustion, solvents, resin products, pesticides, aerosol sprays, cleaning products, building materials, paints

Organic vapors <8 ppba (without combustion appliances) >15 ppb with combustion appliances) 20 µg/m3b

40 to 60 µg/m3a

Combustion, heating system, cooking

Locations

Homes, schools, offices

Mechanical/furnace rooms

Homes, indoor ice rinks

Homes, restaurants, public facilities, offices, hospitals

Indoor ice rinks, homes, cars, vehicle repair shops, parking garages Homes, offices, cars, public facilities, bars, restaurants Homes, offices, transportation, restaurants

NA = not applicable ppb = parts per 109

70 ppba

Airplanes, offices, homes

4 pCi/La Homes, schools 300 to 500 ppmc NA (lower than Homes, hospitals, schools, offices, indoor levels) public facilities

NA

<20 µg/m3b 3 ppba

15 ppba

See Table 11

60 µg/m3a

<10 µg/m3a

2

Typical Outdoor Concentration

Typical Indoor Concentration

Combustion equipment, engines, faulty heating systems Stoves, fireplaces, cigarettes, condensation of 7 to 10 µg/m3a volatiles, aerosol sprays, cooking

Sources of Indoor Contaminants

PM10

PM2.5


Table 2.4 Sources and Indoor and Outdoor Concentrations of Selected Indoor Contaminants [2013F, Ch 11, Tbl 13]



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1 2

1,2 2 2 2 2

Butyl acetate (!) Butyl alcohol Butyl mercaptan Butylene Butyne

1

1

2 1

PIA 1 1 1,2 1 1 1 1 1

2,1 1 1 1 1

1 2,2 1 2 1 2 1

1

2 1 2

AC 2 2 1 2

1

Heptane Hydrogen bromide Hydrogen chloride Hydrogen cyanide Hydrogen fluoride

Gaseous Contaminant Dichlorofloromethane 2,1 R-114 (see note) 2 Diethylamine Dimethylamine Dioctyl phthalate Dioxane 2 Ethanol Ethyl acetate Ethyl chloride (!) Ethylene (C2H4) Ethylene oxide Ethyl ether Ethyl mercaptan (!) Formaldehyde Gasoline General halocarbons General hydrocarbons General VOC

1 1

2 2

1 1 2 1,2 1 1 2 1,1 1 1

2

PIA

1 2 2

1 1 1

2 1 2

AC 1 1 1 1 1 2 2 1 2,1 2

1

1 1

2

AIC BIC

Phosgene Phosphine Putrescine Pyridine (!) Skatole

Gaseous Contaminant Methyl formate Methyl isobutyl ketone Methyl sulfide Methyl vinyl ketone Naphtha Naphthalene Nicotine Nitric acid Nitric oxide (NO) Nitrobenzene Nitrogen dioxide Nitromethane Nitrous oxide Octane (!) Ozone (O3) (!) Perchloroethylene Peroxy acetyl nitrate (PAN) Phenol

Table 2.5 Media Selection by Contaminant [2011A, Ch 46, Tbl 7] AIC BIC


Gaseous Contaminant Acetaldehyde Acetic acid (!) Acetic anhydride (!) Acetone (!) Acetylene Acrolein Acrylic acid (!) Allyl sulfide Ammonia (NH3) Aniline Arsine Benzene Borane (!) Bromine 1,3 Butadiene Butane 2-Butanone 2-Butoxyethanol


2 1 1 1 2

2

2 2 2

1 1

1

1

PIA 2 2 1 2

2 1 1

1

1,1 1,1 1 1 1

1

1 1 1 2

AC 1 1

1

2

1 2

AIC BIC © 2013 ASHRAE (www.ashrae.org). For personal use only. Additional reproduction, distribution, or transmission in either print or digital form is not permitted without ASHRAE's prior written permission.

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Gaseous Contaminant Hydrogen iodide Hydrogen selenide Hydrogen sulfide Iodine Iodoform Isopropanol Kerosene Lactic acid Menthol Mercury vapor Methanol Methyl acrylate Methyl bromide (!) Methyl butyl ketone (!) Methyl cellosolve acetate Methylchloroform Methylcyclohexane Methylene chloride 1

AIC BIC

1 1 1 1 1 1 Impreg. AC 1 1 1 2,1 1 1 1 1

AC

Gaseous Contaminant Silane Stoddard solvent Stibine Styrene (!) Sulfur dioxide Sulfur trioxide Sulfuric acid Toluene Triethylamine Trichlorethylene 1,1,1, trichloroethane (!) R-11 (see below) Turpentine Urea (!) Uric acid (!) Vinyl chloride Xylene 2 2 1

1

PIA 1 1 1 2 1 1 2 1 2 1 2,1 1 1 1,1 1 1 1

1,1

AC

1

2,2

1 1 1

AIC BIC

Comments: Some contaminant molecules have isomers that, because they have different physical properties (boiling point, vapor pressures), require different treatment methods. For some contaminants, preferred treatment is ion exchange or another (nonlisted) impregnated carbon. For some contaminants, manufacturer recommendations differ. “!” is used to identify these cases.

2 2 2,1 1,2 2

2

2 2

1

PIA 2

Table 2.5 Media Selection by Contaminant [2011A, Ch 46, Tbl 7] (Continued)

AC AIC BIC 1 1 2 2 1 1 Carbon w/catalyst 2 1 Carbon w/catalyst 1 1 1 1,2 2,1 1 2 1 2 1 1 1 1 1

PIA 2

1 = primary media selection for contaminant; 2 = secondary media selection. PIA = permanganate-impregnated alumina; AC = activated carbon; AIC = acid-impregnated carbon; BIC = base-impregnated carbon. R-114 is dichlorotetrafluoroethane; R-11 is trichlorofluoromethane.

Gaseous Contaminant Butyraldehyde Butyric acid Cadaverine Camphor Carbon dioxide (CO2) Carbon disulfide Carbon monoxide (CO) Carbon tetrachloride Chlorine (Cl2) Chloroform Creosote (!) Cyclohexane Cyclohexanol Cyclohexanone Cyclohexene Decane Diborane Dichlorobenzene



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4-Phenylcyclo-hexene (PCH) Acetaldehyde Acetic acid Acetone Ethylene glycol Formaldehyde Naphthalene n-Heptane Nonanal Toluene TVOC*

Contaminant

3.6 (n.d.- 41) 11 (n.d.-59) 11 (n.d.-68) 1900 (270-9100)

4.9 (1.7-11)

32 (3.2-150)

8.4 (n.d.- 85) 2.8 (n.d.- 37)

Carpets

5.8 (n.d.-25)

12 (n.d.-33)

Acoustic Ceiling Panels

19 (n.d.-46) 400 (52-850)

9.0 (n.d.-32) 8.4 (n.d.-26) 35 (n.d.-67) 140 (n.d.-290) 220 (n.d.-570) 3.0 (n.d.-8.2) 21 (n.d.-53)

Fiberboards

15 (n.d.-61)

10 (n.d.-28)

6.8 (n.d.-19)

37 (n.d.-110)

Gypsum Boards

Emission Factor Averages (ranges), μg/(h·m2)

2500 (170-6200)

3.7 (n.d.-24)

35 (n.d.-120) 19 (n.d.-190)

Paints on Gypsum Board

Example Generation of Gaseous Contaminants by Building Materials [2011A, Ch 46, Tbl 2]


Table 2.6


420 (240-510)

160 (140-200) 49 (n.d.-97)

28 (n.d.-55)

Particle Boards © 2013 ASHRAE (www.ashrae.org). For personal use only. Additional reproduction, distribution, or transmission in either print or digital form is not permitted without ASHRAE's prior written permission.

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1,2,4-Trimethylbenzene

Contaminant

680 (100-2100)

160 (6.3-310)

15000 (1500-100000)

1.4 (n.d.-11)

5.7 (n.d.- 19) 35 (n.d.- 310) 5.1 (n.d.- 12)

5.6 (n.d.-28)

1.3 (n.d.-20)

1.6 (n.d.-24)

38 (n.d.- 210) 6.8 (n.d.- 79) 3.4 (n.d.- 14)

2.7 (n.d.- 24) 11 (n.d.- 49) 120 (n.d.- 830) 0.51 (n.d. - 5.1)

270 (100-430)

6.6 (6.6)

7.5 (0.57-26)

1.8 (0.57-4)

5.9 (0.35-14)

12 (1.8-21)

140 (13-270) 7100 (1200-13000)

150 (n.d.-300) 340 (n.d.-680)

100 (n.d.-200)

32 (3.6-61)

220 (30-400)

Emission Factor Averages (ranges) in μg/(h·m2) Non-Rubber-Based Rubber-Based Tackable Wall Wall Bases (RubberThermal Insulations Resilient Flooring Resilient Flooring Panels Based) 210 (n.d.-590)

9.4 (4.4-19)

13 (n.d.-29)

75 (4.8-150)

Plastic Laminates and Assemblies

Source: Material Emissions Study, California Integrated Waste Management Board, Publication 433-03-015, 2003. n.d. = nondetectable * TVOC concentrations calculated from total ion current (TIC) from GC/MS analysis by adding areas of integrated peaks with retention times greater than 5 min, subtracting from sum of area of internal standard chlorobenzene-d5, and using response factor of chlorobenzene-d5 as calibration.

2-Butoxy-ethanol Acetaldehyde Acetone Butyric acid Dodecane Ethylene glycol Formaldehyde Naphthalene n-Butanol Nonanal Octane Phenol Toluene Undecane TVOC*


Table 2.6 Example Generation of Gaseous Contaminants by Building Materials [2011A, Ch 46, Tbl 2] (Continued)



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Ultraviolet Lamp Systems UVC (shortwave, ≥80 to 200 mm) lamps are most effective for inactivation of microorganisms, for upper-room air, and for inside ducts. UVC is far lower penetrating than longerwave UV, but can damage eyes and skin. It can also degrade organic materials, such as gaskets, rubber, insulation, and plastic piping. In-room irradiation systems are designed to irradiate air in the upper part of a room. Natural convection will distribute the effect of irradiation. In-duct UVC airstream disinfection systems are generally engineered to achieve a required level of air disinfection. UV fixtures are installed in the supply ducts.

Installation Coils should be cleaned initially to reduce biomass and to accelerate systemwide cleaning and energy savings. UV lamps should be mounted near cooling coils and spaced to allow even distribution of energy over the surface to be disinfected. Qualified UV equipment manufacturers or consultants can assist in system design.


As HVAC equipment ages, its performance can degrade, and so may the quality of air it delivers to occupied spaces. Cooling coils can act as filters to collect and retain a substantial amount of particulates, including microbes. These materials are quite small, so this occurs even in a system with reasonable or good filtration. Between 30 and 100% rh, damp coil and drain pan conditions are excellent forums for the growth of bacteria and mold. Coil fouling also increases coil pressure drop and reduces airflow, reducing heat transfer from coil fins to lessen the amount of work a system can perform and reducing indoor environmental quality (IEQ). It can contribute to sick building syndrome and building-related illnesses ranging from mild irritations to the spread of infectious agents. The decaying accumulation is often a source of odor, as well.

UVGI fixtures for HVAC equipment must be designed to withstand moisture and condensate (from the coil or caused by reduced operating temperatures) and to operate properly over the full range of system operating temperatures. Care must be taken at the installation site to ensure that electrical interlocks are included to deenergize the UV system when it is accessed. UV systems should operate continuously to maximize UV’s benefits and to improve lamp life, and to counteract mold and bacteria growth that occurs when an HVAC system is not operating. Workers should be made aware of hazards in the work area and trained in precautions to protect themselves. Workers expected to clean up broken lamps should be trained in proper protection, cleanup, and disposal. Access to lamps should only be allowed when lamps are deenergized. The lamps should be turned off before air-handling unit (AHU) or fan shutdown to allow the lamps to cool and to purge any ozone in the lamp chamber (if ozone-producing lamps are used). If AHUs or fans are deenergized first, the lamp chamber should be opened and allowed to ventilate for several minutes. Workers should always wear protective eyewear and puncture-resistant gloves for protection in case a lamp breaks. Table 2.7 Advantages and Disadvantages of UVC Fixture Location Relative to Coil Location

Advantages • More space to install fixtures. • Allows fixtures to better irradiate surface where condensation is highest. Downstream • Allows fixtures to irradiate generally most contaminated part of coil and drain pan. • Lamp and fixture may be subjected to less moisture. • May be the only location to apply Upstream fixtures. • Fewer lamps and fixtures may be needed than on downstream side.

Disadvantages • Lamp and fixture must be rated for damp location. • Lamp cooling effects may reduce UV output, or require windchill correction or more lamps and fixtures for a given result. • May not allow enough space to install fixtures. • May initially take longer to clean coil and may not disinfect drain pan.

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Figure 2.2 Typical Elevation View of Upper-Room UV Applied in Hospital Patient Room

Figure 2.3 UV Lamps Upstream or Downstream of Coil and Drain Pan

Figure 2.4

Typical UVGI Lamp

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Hood Capture Velocities To select an adequate volumetric flow rate to withdraw air through a hood, select a capture velocity, which is air velocity at the point of contaminant generation. The contaminant enters the moving airstream at the point of generation and is conducted along with the air into the hood. Table 2.8 shows capture velocities for several industrial operations, based on successful experience under ideal conditions. Upper End of Range 1. Distributing room air currents. 2. Contaminants of high toxicity. 3. High production, heavy use. 4. Small hood; local control only.

Principles of Hood Design Optimization • • • • • •

Hood location should be as close as possible to the source of contamination. The hood opening should be positioned so that it causes the contaminant to deviate the least from its natural path. The hood should be located so that the contaminant is drawn away from the operator’s breathing zone. Hood size must be the same as or larger than the cross section of flow entering the hood. If the hood is smaller than the flow, a higher volumetric flow rate is required. Worker position with relation to contaminant source, hood design, and airflow path should be evaluated based on the principles given in Chapters 6 and 13 of ACGIH (2007). Canopy hoods should not be used where the operator must bend over a tank or process (ACGIH 2007).


Lower End of Range 1. Room air currents are favorable to capture. 2. Contaminants of low toxicity or of nuisance value only. 3. Intermittent, low production. 4. Large hood; large air mass in motion.

Table 2.8 Range of Capture Velocities Condition of Contaminant Dispersion Released with essentially no velocity into still air Released at low velocity into moderately still air Active generation into zone of rapid air motion Released at high velocity into zone of very rapid air motion

Examples Evaporation from tanks, degreasing, plating Container filling, low-speed conveyer transfers, welding Barrel filling, chute loading of conveyors, crushing, cool shakeout Grinding, abrasive blasting, tumbling, hot shakeout

Capture (Control) Velocity, fpm 50 to 100 100 to 200 200 to 500 500 to 2000

For each condition above, a range of capture velocities is shown. The proper choice of values depends on several factors.

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Figure 2.5 Velocity Contours for a Plain Round Opening

Figure 2.6

Velocity Contours for a Plain Rectangular Opening with Sides in a 1:3 Ratio

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Exhaust Duct Design and Construction

Table 2.9

Contaminant Transport Velocities [2011A, Ch 32, Tbl 2]

Nature of Contaminant Vapor, gases, smoke Fumes Very fine light dust Dry dusts and powders

Average industrial dust

Heavy dust

Heavy and moist dust

Examples All vapors, gases, smoke Welding Cotton lint, wood flour, litho powder Fine rubber dust, molding powder dust, jute lint, cotton dust, shavings (light), soap dust, leather shavings Grinding dust, buffing lint (dry), wool jute dust (shaker waste), coffee beans, shoe dust, granite dust, silica flour, general material handling, brick cutting, clay dust, foundry (general), limestone dust, asbestos dust in textile industries Sawdust (heavy and wet), metal turnings, foundry tumbling barrels and shakeout, sandblast dust, wood blocks, hog waste, brass turnings, cast-iron boring dust, lead dust Lead dust with small chips, moist cement dust, asbestos chunks from transite pipe cutting machines, buffing lint (sticky), quicklime dust

Minimum Transport Velocity, fpm


Duct Considerations The second component of a local exhaust ventilation system is the duct through which contaminated air is transported from the hood(s). Round ducts are preferred because they (1) offer a more uniform air velocity to resist settling of material and (2) can withstand the higher static pressures normally found in exhaust systems. When design limitations require rectangular ducts, the aspect ratio (height-to-width ratio) should be as close to unity as possible. Minimum transport velocity is the velocity required to transport particulates without settling. Table 2.9 lists some generally accepted transport velocities as a function of the nature of the contaminants. The values listed are typically higher than theoretical and experimental values to account for (1) damage to ducts, which would increase system resistance and reduce volumetric flow and duct velocity; (2) duct leakage, which tends to decrease velocity in the duct system upstream of the leak; (3) fan wheel corrosion or erosion and/or belt slippage, which could reduce fan volume; and (4) reentrainment of settled particulate caused by improper operation of the exhaust system. Design velocities can be higher than the minimum transport velocities but should never be significantly lower.

Usually 1000 to 2000 2000 to 2500 2500 to 3000 3000 to 4000

3500 to 4000

4000 to 4500

4500 and up

Source: From American Conference of Governmental Industrial Hygienists (ACGIH®), Industrial Ventilation: A Manual of Recommended Practice, 27th ed. Copyright 2010. Reprinted with permission.

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Hood Entry Loss When air enters a hood, a loss of total pressure occurs; the hood entry loss is pe = Co pv


where  pe = Co = pv =

hood entry loss, in. of water loss factor, dimensionless appropriate velocity pressure, in. of water

Total pressure is difficult to measure, since it varies across a duct, depending on local velocity. On the other hand, static pressure remains constant across a straight duct. Therefore, a single measurement of static pressure in a straight duct downstream of the hood can monitor the volumetric flow rate. The value of this static pressure, hood suction, is given by phs = pv + pe where phs = hood suction, in. of water.

Figure 2.7 Entry Losses for Typical Hoods

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Kitchen Ventilation (See NFPA 96 and ASHRAE Standard 154) Hoods


Type I Hoods. Type I hoods for removal of grease and smoke are unlisted, which meet the design, construction, and performance criteria of the applicable national and local codes and are not allowed to have fire-actuated exhaust dampers, or listed with design, construction, and performance to UL Standard 710. Type II refers to all other hoods. Among Type I Listed hoods, there are two basic subcategories, (1) exhaust hoods without exhaust dampers and (2) exhaust hoods with exhaust dampers. Grease removal devices in Type I hoods operate on the principle in which a centrifugal force is created as the exhaust air passes around baffles to extract the grease. Device types: • Baffle filters have a series of vertical baffles designed to capture grease and drain it into a container. The filters are arranged in a channel or bracket for easy insertion and removal for cleaning. Each hood usually has two or more baffle filters, which are typically constructed of aluminum, steel, or stainless steel and come in various standard sizes. Filters are cleaned by running them through a dishwasher or by soaking and rinsing. NFPA Standard 96 requires that grease filters be listed. Listed grease filters are tested and certified by a nationally recognized test laboratory in accordance with UL Standard 1046. • Removable extractors (also called cartridge filters) have a single horizontal-slot air inlet. The filters are arranged in a channel or bracket for easy insertion and removal for cleaning. Each hood usually has two or more removable extractors, which are typically constructed of stainless steel and contain a series of horizontal baffles designed to remove grease and drain it into a container. Available in various sizes, they are cleaned by running them through a dishwasher or by soaking and rinsing. Removable extractors may be classified by a nationally recognized test laboratory in accordance with UL Standard 1046, or may be listed as part of the hood in accordance with UL Standard 710. Hoods that are listed with removable extractors cannot have those extractors replaced by other extractors. • Stationary extractors are integral to the listed water-wash exhaust hoods and are typically constructed of stainless steel and contain a series of horizontal baffles that run the full length of the hood. The baffles are not removable for cleaning, though some have doors that can be removed to clean the extractors and plenum. The stationary extractor includes one or more water manifolds with spray nozzles that, when activated, wash the grease extractor with hot, detergent-injected water, removing accumulated grease. The wash cycle is typically activated at the end of the day, after cooking equipment and fans have been turned off; however, it can be activated more frequently. The cycle lasts 5 to 10 min, depending on the hood manufacturer, type of cooking, duration of operation, and water temperature and pressure. Most water-wash hood manufacturers recommend a water temperature of 130°F to 180°F and water pressure of 30 to 80 psi. Average water consumption varies from 0.50 to 1.50 gpm per linear foot of hood, depending on manufacturer. Most water-wash hood manufacturers provide a manual and/or automatic means of activating the water-wash system in the event of a fire. Some water-wash hood manufacturers provide continuous cold water as an option. The cold water runs continuously during cooking and may or may not be recirculated, depending on the manufacturer. Typical cold-water usage is 1 gph per linear foot of hood. The advantage of this method is that it improves grease extraction and removal, partly through condensation of the grease. Many hood manufacturers recommend continuous cold water in hoods located over solid-fuel-burning cooking equipment, because the water also extinguishes hot embers that may be drawn up into the hood and helps cool the exhaust stream. • Multistage filters use two or more stages of filtration to remove a larger percentage of grease. They typically consist of a baffle filter or removable extractor followed by a higher-efficiency filter, such as a packed bead bed. Each hood usually has two or more multistage filters, which are typically constructed of aluminum or stainless steel and are available in standard sizes. Filters are cleaned by running them through a dishwasher or by soaking and rinsing. NFPA Standard 96 requires that grease filters be listed, so these multistage filters must be tested and certified by a nationally recognized test laboratory in accordance with UL Standard 1046. 51

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Table 2.10 Minimum Overhang Requirements


Type of Hood Wall-mounted canopy Single-island canopy Double-island canopy Eyebrow Backshelf/Pass-over

Type of Hood (Unlisted) Wall-mounted canopy Single island Double island (per side) Eyebrow Backshelf/Pass-over

End Overhang Front Overhang Rear Overhang 6 in. 6 in. N/A 6 in. 6 in. 6 in. 6 in. 6 in. N/A N/A 6 in. N/A 6 in. 10 in. (setback) N/A Minimum Net Exhaust Flow Rate, cfm per Linear Foot of Hood Length Light Medium Heavy Extra Heavy Duty Duty Duty Duty Equipment Equipment Equipment Equipment 200 300 400 550 400 500 600 700 250 300 400 550 250 250 Not allowed Not allowed 300 300 400 Not allowed

N/A = not applicable Exceptions: 1. Side Panels. Overhang is not required where full side panels or partial side panels (panels angled from the front lip of the hood to the rear of the hood at cooking-surface height) are provided to reduce the open area between the appliances and the hood. 2. Listed hoods are to be installed in accordance with the terms of their listing organization and their manufacturer’s installation instructions.

Table 2.11 Kitchen Exhaust Hood Exhaust Static Pressure Loss for Hoods for Various Exhaust Airflows Type of Grease Removal Device Baffle filter Extractor

Static Pressure Loss, in. of water gage 150 to 250 cfm/ft 250 to 350 cfm/ft 350 to 450 cfm/ft 0.25 to 0.50 0.50 to 0.75 0.75 to 1.00 1.00 to 1.35 1.30 to 1.70 1.70

500+ cfm/ft 1.00+ 1.70

Type II Hoods. Type II hoods can be divided into the following two application categories: • Condensate hood. For high-moisture exhaust, condensate will form on interior hood surfaces. The hood is designed to direct condensate toward a perimeter gutter for collection and drainage. Flow rates are typically 50 to 75 cfm per square foot of hood opening. Hood material is usually noncorrosive, and filters are usually installed. • Heat/fume hood. For applications over equipment producing heat and fumes only, flow rates are typically 50 to 100 cfm per square foot of hood opening. Filters are usually not installed. Makeup Air Options Air exhausted from the kitchen space must be replaced. It can be brought in through ceiling registers located so that the discharged air does not disrupt the air pattern entering the hood. Air should be supplied either (1) as far from the hood as possible or (2) close to the hood and directed away from the hood or straight down at very low velocity. Makeup air, internal discharge, delivers air to the interior of the hood without entering the occupied space.

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Duct Systems The exhaust ductwork conveys the exhaust air to outdoors, with any grease, smoke, VOCs, and odors. To be effective, the ductwork must be greasetight and clear of combustibles; and ducts must be sized to convey the volume of air necessary to remove the effluent. The ductwork should not have traps that can hold grease, and ducts should pitch toward the hood for constant drainage of liquefied grease or condensates. On long duct runs, allowance must be made for possible thermal expansion due to a fire. Minimum duct velocity is 500 ft/min. Access panels are required for cleaning.


Exhaust Fans Kitchen exhaust fans must be capable of handling hot, grease-laden air. The fan should be designed to keep the motor out of the airstream and effectively cooled. Roof location is preferred. To prevent roof damage, the fan should contain and properly drain all grease removed from the airstream. The following types of exhaust fans are in common use (all have centrifugal wheels with backward-inclined blades): • Upblast. Aluminum fans for roof mounting directly on top of the exhaust stack, with upward discharge listed for the service. They typically can provide static pressures of only up to 1 in. water gage. These fans allow easy access for duct cleaning because they generally hinge back from the duct. • Utility set. Steel fans, roof mounted, single width, single inlet. They can operate at medium to high static pressure. Care must be taken to drain the low part of the fan to a safe remote container. • Inline. Steel fans typically located in the duct run inside a building where exterior fan mounting is not practical for wall or roof exhaust. The gasketed flange mounting must be greasetight, still removable for service. A pan must be placed under the entire assembly in event of a grease leak at the flanges. Fire Suppression Exhaust systems serving grease-producing equipment must include a fire-extinguishing system unless listed grease removal devices are installed. Wet chemical systems with nozzles over cooking equipment, in the hood and at the duct collar downstream of hood are commonly used, per NFPA 17A. Water from wet-pipe sprinkler systems can be used, per NFPA 13.

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Laboratory Hoods


Laboratory operations potentially involve hazard. Use of biological safety cabinets may be required. Review laboratory design parameters with safety officer and scientific staff.

Figure 2.8 Bypass Fume Hood with Vertical Sash and Bypass Air Inlet [2011A, Ch 16, Fig 1]

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Clean Spaces


Airborne particles include pollen, bacteria, and windblown dust and sea spray. Industry generates particles from combustion, chemical vapors, and friction in equipment. People are a prime source of particles, as skin flakes, lint, cosmetics, and respiratory emissions. Airborne particles vary in size from 0.001 m to several hundred micron. Particles larger than 5 m tend to settle quickly. Cleanroom personnel are potentially the largest source of internal particles. Personnel generated particles are controlled with airflow designed to continually “wash” the personnel with clean air, new cleanroom garments, and proper gowning procedures. Externally generated particles are prevented from entering the cleanroom with high efficiency air filters centered around two types: high efficiency particulate air (HEPA) filters and ultra low penetration air (ULPA) filters. HEPA filters are more frequently used. Both HEPA and ULPA filters use glass fiber paper technology.They are deep pleated with either aluminum, coated string, or filter paper as pleating separators. Filters may vary from 2 to 12 in. in depth; correspondingly higher media area is available with deeper filters and more concentrated pleat spacing. Fibrous filters have their lowest removal efficiency at the most penetrating particle size (MPPS), determined by filter fiber diameter, volume fraction or packing density, and air velocity. For most HEPA filters the MPPS is between 0.1 and 0.3 m. Thus HEPA and ULPA filters have rated efficiencies based on 0.3 m and 0.12 m particle sizes, respectively. The selection of the air pattern configurations is the first step for cleanroom design. Requirements for cleanliness level, process equipment layout, available space for installation of air pattern control equipment all influence the air pattern design selection. Project financial aspects may limit the type and size of air handling equipment to be used and resulting air pattern control. Unidirectional airflow, is air flowing in a single pass in a single direction through a cleanroom or clean zone with generally parallel streamlines. Although personnel and equipment in the airstream distort the streamlines, constant velocity is approximated. Nonunidirectional airflow may have multiple pass circulating characteristics or a nonparallel flow direction. Nonunidirectional airflow may provide satisfactory contamination control results for cleanliness levels of ISO Class 6 through ISO Class 8. When internally generated particles are of primary concern, clean work stations are provided in the clean space. Air patterns and air turbulence reduction are optimized in unidirectional airflow systems. In a vertical laminar flow (VLF) room, air is introduced through the ceiling and returned through a raised floor or at the base of sidewalls. In a cleanroom with a low class number, the greater part of the ceiling requires HEPA filters. For an ISO Class 5 room, the entire ceiling will usually require HEPA filtration. Ideally, a grated or perforated floor serves as the air exhaust. Pharmaceutical cleanrooms typically have solid floors and low level returns. Widely accepted velocity is 90 fpm. In a horizontal flow, the supply wall consists entirely of HEPA filters supplying air at a velocity of approximately 90 fpm across the entire section of the room. The air exits through the return wall at the opposite end of the room This design removes contamination generated in the space at a rate equal to the air velocity and does not allow cross-contamination perpendicular to the airflow. A major limitation to this design is that downstream air becomes contaminated.

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Table 2.12

Airborne Particle Concentration Limits

CLEAN SPACES ISO Standard 14644 Section 1* *Replaced US Federal Standard 209CE, Airborne Particulate Classes in Cleanrooms and Clean Zones


ISO Class

Equivalent FS 209 Class

Number of Particles Per Cubic Metre by Size (micrometres) 0.1 m

0.2 m

0.3 m

0.5 m

1 m

5 m

1

–

10

2

–

–

–

–

2

–

100

24

10

4

–

–

3

1

1,000

237

102

35

8

–

4

10

10,000

2,370

1,020

352

83

–

5

100

100,000

23,700

10,200

3,520

832

29

6

1,000

1,000,000 237,000

102,000

35,200

8,320

293

7

10,000

–

–

–

352,000

83,200

2,930

8

100,000

–

–

–

3,520,000 832,000

9

–

–

–

–

35,200,000 8,320,000 293,000

29,300

Figure 2.9 ISO Class 7 (FS 209 Class 10,000) Nonunidirectional Cleanroom with Ducted HEPA Filter Supply Elements and ISO Class 5 (FS 209 Class 100) Unidirectional Cleanroom with Ducted HEPA or ULPA Filter Ceiling

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3.

WATER Table 3.1 Common Pump Terms, Symbols, and Formulas

Term Velocity Volume Flow rate Pressure Density Acceleration of gravity Speed

Symbol v V Qv p  g n

Units ft/s ft3 gpm psi lb/ft3 32.17 ft/s2 rpm

Specific gravity

SG

—

Head Net positive suction head (NPSH) Efficiency (percent) Pump Electric motor Variable speed drive Equipment (constant-speed pumps) Equipment (variable-speed pumps) Utilization QD = design flow QA = actual flow HD = design head HA = actual head System Efficiency Index (decimal) Output power (pump) Shaft power Input power

H H

ft ft

Constant

Variable

Constant

Speed

Variable

Constant

Constant

Mass of liquid = ---------------------------------------------------Mass of water at 39°F 2.31 p/SG

p m v e

e = pm /100

e

e = 10–4pmv

u Water

Table 3.2 Impeller Diameter

Formula

QD HD  u = 100 ---------------QA H A

Po Ps Pi

SEI = 10–4u QvHSG/3960 100Po /p 74.6Ps /m

hp hp kW

Affinity Laws for Pumps Specific Gravity (SG)

Constant

Constant

Variable

To Correct for

Multiply by

Flow

Speed-  New ------------------------- Old Speed 

Head


2

Power


3

Flow

Diameter-  New --------------------------------- Old Diameter 

Head


2

Power


3

Power

SG-  New ------------------ Old SG  57

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Water

gpm  ft head  sp. gr. pump hp = -----------------------------------------------------------------------------------------------------3960  pump efficiency  motor efficiency

Figure 3.1 Pump Curves and System Curves

If the hydronic system has a system head curve as shown in curve A, the pump at 1150 rpm will operate at point 1, not at point 2, as would be predicted by the affinity laws alone. If the hydronic system has a system head curve like curve B of Figure 3.1, the pump at 1150 rpm will run at shutoff head and deliver no water. This demonstrates that the affinity laws should be used to develop new pump head/capacity curves, but not to predict performance with a particular hydronic system unless its system head curve is known.

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Net Positive Suction Characteristics Particular attention must be given to the pressure and temperature of the water as it enters the pump, especially in condenser towers, steam condensate returns, and steam boiler feeds. The pressure in excess of that required to prevent vapor pockets from forming is the net positive suction head required (NPSHR). NPSHR is a characteristic of a given pump and varies with pump speed and flow. It is determined by the manufacturer and is included on the pump performance curve. If the absolute pressure at the suction nozzle approaches the vapor pressure of the liquid, vapor pockets form in the impeller passages. The collapse of the vapor pockets (cavitation) is noisy and can be destructive to the pump impeller. NPSHR is particularly important when a pump is operating with hot liquids or is applied to a circuit having a suction lift. The vapor pressure increases with water temperature and reduces the net positive suction head available (NPSHA). Each pump has its NPSHR, and the installation has its NPSHA, which is the total useful energy above the vapor pressure at the pump inlet. NPSHA = hp + h z – h vpa – h f where hp = hz = hvpa hf

= =

absolute pressure on surface of liquid that enters pump, ft of head static elevation of liquid above center line of pump (hz is negative if liquid level is below pump center line), ft absolute vapor pressure at pumping temperature, ft friction and head losses in suction piping, ft

To determine the NPSHA in an existing installation, the following equation may be used (see Figure 3.2):

where ha = hs = V 2/2g =

Water

2 NPSHA = h a + h s + V ------ – h vpa 2g

atmospheric head for elevation of installation, ft head at inlet flange corrected to center line of pump (hs is negative if below atmospheric pressure), ft velocity head at point of measurement of hs , ft

For trouble-free design, the NPSHA must always be greater than the pump’s NPSHR. In closed hot- and chilled-water systems where sufficient system fill pressure is exerted on the pump suction, NPSHR is normally not a factor.

Figure 3.2

Net Positive Suction Head Available [2012S, Ch 44, Fig 31] 59

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Water

Figure 3.3 Pump Selection Regions

Figure 3.4 Operating Conditions for Parallel Operation

Figure 3.5 Construction of Curve for Dissimilar Parallel Pumps 60

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Figure 3.6

Typical Pump Curves (Curves Vary by Manufacturer) [2012S, Ch 44, Fig 11]

Water

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General Information on Water

60°F 1.12 1.12

70°F .98 .98

80°F .86 .86

100°F .68 .69

Ton (U.S.)* Litre Cubic Metre

a. Volume—weight relationship taken for water at greatest density (39.2°F).

199.6 .22 220.

239.6 .2642 264.2

U.S. Gallon Imperial Gallon Cubic Inch Cubic Foot Pounda Cwt (U.S.)*  61.023 

Cubic Inch 231. 22.741 1. 1728. 27.68 2765. 32.04 .0353 35.314

Cubic Foot .13368 .1605 .000579 1. .01602 1.602 2000. 2.205 2204.5

Convert to * Pound 8.345 10.02 .036124 62.425 1. 100.

Table 3.4 Weight and Volume Equivalents

50°F 1.31 1.31

Imperial Gallon .8327 1. .003607 6.229 .0998 9.98

32°F 1.70 1.79

U.S. Gallon 1. 1.201 .004329 7.4805 .1198 11.98

Convert from

Absolute viscosity, centipoises Kinematic viscosity, centistokes

Viscosity of water varies as follows:

20.0 .022 22.045

* Cwt (U.S.) .08345 .1002 – .6243 .01 1.

120°F .56 .57

1. .0011 1.102

Litre 3.785 4.546 .0164 28.317 .454 45.36

180°F .35 .36

906.9 1. 1000.

160°F .40 .41

* Ton (U.S.) .00418 .00502 – .03121 .0005 .05

140°F .47 .45

.907 .001 1.

Cubic Metre .00378 .00455 – .0283 .045

212°F .28 .29

Specific gravity of water is usually given as 1.0 at 60°F. However, for some purposes it is given as 1.0 at 39.2°F, the point of maximum density. Based on water at 39.2°F as 1.0, water at 60°F has a specific gravity of 0.999. Therefore, which base is selected makes no practical difference.

Table 3.3

Water



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Water

Figure 3.7 Mass Flow and Specific Heat of Water

Table 3.5 Freezing Points for Solutions of Ethylene Glycol and Propylene Glycol Glycol, % by mass 10 15 20 25 30 40 50 60

Ethylene Glycol °F 26.2 22.2 17.9 12.7 6.7 8.1 28.9 54.8

Propylene Glycol °F 26.1 22.9 19.2 14.7 9.2 6.0 28.3 59.9

Ethylene glycol solutions are less viscous than propylene glycol solutions at the same concentration. Less toxic propylene glycol is preferred for applications involving possible human contact. 63

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Table 3.6

Volume of Vertical Cylindrical Tanks in Gallons per Foot of Depth

Diameter in ft in. 1 0 1 2 1 4 1 6 1 8 1 10 2 0 2 2 2 4 2 6 2 8 2 10 3 0 3 3

2 4

Water

Table 3.7 % Depth Filled 1 3 5 7 9 11 13 15 17 19 21 23 25

5.875 7.997 10.44 13.22 16.32 19.75 23.50 27.58 31.99 36.72 41.78 47.16 52.88

Diameter in ft in. 3 6 3 8 3 10 4 0 4 2 4 4 4 6 4 8 4 10 5 0 5 2 5 4 5 6

58.92 65.28

5 5

U.S. Gallons

8 10

U.S. Gallons 71.97 78.99 86.33 94.00 102.0 110.3 119.0 127.9 137.3 146.9 156.8 167.1 177.7 188.7 199.9

Diameter in ft in. 6 0 6 6 7 0 7 6 8 0 8 6 9 0 9 6 10 0 10 6 11 0 11 6 12 0 12

6

U.S. Gallons 211.5 248.2 287.9 330.5 376.0 424.5 475.9 530.2 587.5 647.7 710.9 777.0 846.0 918.0

Quantities for Various Depths of Vertical Cylindrical Tanks in Horizontal Position

% of % Depth % of % Depth % of % Depth % of Capacity Filled Capacity Filled Capacity Filled Capacity .20 26 20.73 51 51.27 76 81.50 .90 28 23.00 53 53.81 78 83.68 1.87 30 25.31 55 56.34 80 85.77 3.07 32 27.66 57 58.86 82 87.76 4.45 34 30.03 59 61.36 84 89.68 5.98 36 32.44 61 63.86 86 91.50 7.64 38 34.90 63 66.34 88 93.20 9.40 40 37.36 65 68.81 90 94.80 11.27 42 39.89 67 71.16 92 96.26 13.23 44 42.40 69 73.52 94 97.55 15.26 46 44.92 71 75.93 96 98.66 17.40 48 47.45 73 78.14 98 99.50 19.61 50 50.00 75 80.39 100 100.0

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8 10 12

(200) (250) (300)

30 30 30

Schedule No. — 40 — 40 40 40 40 40 40 40 40 40 40 40 8.071 10.136 12.090

(205.0) (257.5) (307.1)

2.66 4.19 5.96

(33.03) (52.04) (74.02)

Standard Steel Pipe Inside Diameter Volume in. (mm) gal/ft (L/m) — — — — 0.622 (15.8) 0.0157 (0.19) — — — — 0.824 (20.9) 0.0277 (0.34) 1.049 (26.6) 0.0449 (0.56) 1.380 (35.0) 0.0779 (0.97) 1.610 (40.9) 0.106 (1.32) 2.067 (52.5) 0.174 (2.16) 2.469 (62.7) 0.249 (3.09) 3.068 (77.9) 0.384 (4.77) 3.548 (90.1) 0.514 (6.38) 4.026 (102.3) 0.661 (8.21) 5.047 (128.2) 1.04 (12.92) 6.065 (154.1) 1.50 (18.63)

Water

Nominal Pipe Size in. (mm) 3/8 (10) 1/2 (15) 5/8 (16) 3/4 (20) 1 (25) 1 1/4 (32) 1 1/2 (40) 2 (50) 2 1/2 (65) 3 (80) 3 1/2 (90) 4 (100) 5 (125) 6 (150) 7.725 9.625 11.565

(196.2) (244.5) (293.8)

2.43 3.78 5.46

(30.18) (46.95) (67.81)

Type L Copper Tube Inside Diameter Volume in. (mm) gal/ft (L/m) 0.430 (10.9) 0.0075 (0.09) 0.545 (13.8) 0.0121 (0.15) 0.666 (16.9) 0.0181 (0.22) 0.785 (19.9) 0.0251 (0.31) 1.025 (26.0) 0.0429 (0.53) 1.265 (32.1) 0.0653 (0.81) 1.505 (38.2) 0.0924 (1.15) 1.985 (50.4) 0.161 (2.00) 2.465 (62.6) 0.248 (3.08) 2.945 (74.8) 0.354 (4.40) 3.425 (87.0) 0.479 (5.95) 3.905 (99.2) 0.622 (7.73) 4.875 (123.8) 0.970 (12.05) 5.845 (148.5) 1.39 (17.26)

Table 3.8 Volume of Water in Standard Pipe and Tube



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Friction Loss for Water in Copper Tubing (Types K, L, M) [2013F, Ch 22, Fig 5] Figure 3.8

Water



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Figure 3.9 Friction Loss for Water in Plastic Pipe (Schedule 80) [2013F, Ch 22, Fig 6]

Water



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Figure 3.10 Friction Loss for Water in Commercial Steel Pipe (Schedule 40) [2013F, Ch 22, Fig 4]

Water



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Valve and Fitting Losses Valves and fittings cause pressure losses greater than those caused by the pipe alone. One formulation expresses losses as  V2 V2 p = K  -----  ------ or h = K -----gc 2 2g where K = geometry- and size-dependent loss coefficient (see following tables). ASHRAE research project RP-1193 found the data in the following tables giving K factors for Schedule 80 PVC 2, 4, 6, and 8 in. ells, reducers, expansions, and tees. In general, PVC fitting geometry varied much more from one manufacturer to another than steel fittings did.

Calculating Pressure Losses The most common engineering design flow loss calculation selects a pipe size for the desired total flow rate and available or allowable pressure drop. Because either formulation of fitting losses requires a known diameter, pipe size must be selected before calculating the detailed influence of fittings. A frequently used rule of thumb assumes that the design length of pipe is 50 to 100% longer than actual to account for fitting losses. After a pipe diameter has been selected on this basis, the influence of each fitting can be evaluated.

Water

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90° 90° LongStandard Radius Elbow Elbow 2.5 — 2.1 — 1.7 0.92 1.5 0.78 1.3 0.65 1.2 0.54 1.0 0.42 0.85 0.35 0.80 0.31 0.70 0.24 Return Bend 2.5 2.1 1.7 1.5 1.3 1.2 1.0 0.85 0.80 0.70

45° Elbow 0.38 0.37 0.35 0.34 0.33 0.32 0.31 0.30 0.29 0.28

Table 3.9

Source: Engineering Data Book (Hydraulic Institute 1990).

Nominal Pipe Dia., in. 3/8 1/2 3/4 1 1 1/4 1 1/2 2 2 1/2 3 4 0.90 0.90 0.90 0.90 0.90 0.90 0.90 0.90 0.90 0.90

TeeLine 2.7 2.4 2.1 1.8 1.7 1.6 1.4 1.3 1.2 1.1

TeeBranch 20 14 10 9 8.5 8 7 6.5 6 5.7

Globe Valve 0.40 0.33 0.28 0.24 0.22 0.19 0.17 0.16 0.14 0.12

Gate Valve — — 6.1 4.6 3.6 2.9 2.1 1.6 1.3 1.0

Angle Valve

K Factors: Threaded Pipe Fittings [2013F, Ch 22, Tbl 1]

Water


Swing Check Valve 8.0 5.5 3.7 3.0 2.7 2.5 2.3 2.2 2.1 2.0

Bell Mouth Inlet 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5

Square Inlet

1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0

Projected Inlet


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0.43 0.41 0.40 0.38 0.35 0.34 0.31 0.29 0.27 0.25 0.24

1 1 1/4 1 1/2 2 2 1/2 3 4 6 8 10 12

0.41 0.37 0.35 0.30 0.28 0.25 0.22 0.18 0.16 0.14 0.13

90° LongRadius Elbow 0.22 0.22 0.21 0.20 0.19 0.18 0.18 0.17 0.17 0.16 0.16

45° LongRadius Elbow 0.43 0.41 0.40 0.38 0.35 0.34 0.31 0.29 0.27 0.25 0.24

Return Bend Standard 0.43 0.38 0.35 0.30 0.27 0.25 0.22 0.18 0.15 0.14 0.13

Return Bend LongRadius 0.26 0.25 0.23 0.20 0.18 0.17 0.15 0.12 0.10 0.09 0.08

TeeLine 1.0 0.95 0.90 0.84 0.79 0.76 0.70 0.62 0.58 0.53 0.50

TeeBranch 13 12 10 9 8 7 6.5 6 5.7 5.7 5.7

Globe Valve

Table 3.10 K Factors: Flanged Welded Pipe Fittings [2013F, Ch 22, Tbl 2]

Source: Engineering Data Book (Hydraulic Institute 1990).

90° Standard Elbow

Water

Nominal Pipe Dia., in.


— — — 0.34 0.27 0.22 0.16 0.10 0.08 0.06 0.05

Gate Valve 4.8 3.7 3.0 2.5 2.3 2.2 2.1 2.1 2.1 2.1 2.1

Angle Valve

2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0

Swing Check Valve


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Table 3.11

Summary of K Values for Reducers and Expansions [2013F, Ch 22, Tbl 4] 4 fps 0.53 0.23 0.62 0.31 0.16 0.14 0.17 0.16 0.053 0.16 0.11 0.28 0.15 0.11 0.11 0.073 0.024 0.020

Reducer (2 by 1.5 in.) thread (4 by 3 in.) weld (6 by 4 in.) weld (8 by 6 in.) weld (10 by 8 in.) weld (12 by 10 in.) weld (16 by 12 in.) weld (20 by 16 in.) weld (24 by 20 in.) weld Expansion (1.5 by 2 in.) thread (3 by 4 in.) weld (4 by 6 in.) weld (6 by 8 in.) weld (8 by 10 in.) weld (10 by 12 in.) weld (12 by 16 in.) weld (16 by 20 in.) weld (20 by 24 in.) weld

Water

Source: Rahmeyer (2003a).

Table 3.12

2 in. thread tee,

4 in.weld tee,

6 in.weld tee,

8 in.weld tee,

10 in.weld tee,

12 in.weld tee, 100% mix 16 in.weld tee,

aRahmeyer

a

Rahmeyer (1999a, 2002a).

ASHRAE Researcha,b 8 fps 12 fps 0.28 0.20 0.14 0.10 0.54 0.53 0.28 0.26 0.14 0.14 0.14 0.14 0.16 0.17 0.13 0.13 0.053 0.055 0.13 0.02 0.11 0.11 0.28 0.29 0.12 0.11 0.09 0.08 0.11 0.11 0.076 0.073 0.021 0.022 0.023 0.020 b

Ding et al. (2005)

Summary of Test Data for Pipe Tees [2013F, Ch 22, Tbl 5] ASHRAE Researcha,b 4 fps 8 fps 12 fps 0.93 — — 0.19 — — 1.19 — — 0.57 — — 0.06 — — 0.49 — — 0.56 — — 0.12 — — 0.88 — — 0.53 — — 0.08 — — 0.70 — — 0.52 — — 0.06 — — 0.77 — 0.70 0.63 0.62 0.062 0.091 0.096 0.88 0.72 0.72 0.54 0.55 0.54 0.032 0.028 0.028 0.74 0.74 0.76

100% branch 100% line (flow-through) 100% mix 100% branch 100% line (flow-through) 100% mix 100% branch 100% line (flow-through) 100% mix 100% branch 100% line (flow-through) 100% mix 100% branch 100% line (flow-through) 100% mix 100% branch 100% line (flow-through) 100% branch 100% line (flow-through) 100% mix

(1999b, 2002b).

bDing

et al. (2005).

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Table 3.13 Test Summary for Loss Coefficients K and Equivalent Loss Lengths [2013F, Ch 22, Tbl 6]

2 in.

K 0.91 to 1.00

L, ft 8.4 to 9.2

4 in.

0.86 to 0.91

18.3 to 19.3

6 in.

0.76 to 0.91

26.2 to 31.3

8 in.

0.68 to 0.87

32.9 to 42.1

8 in. fabricated elbow, Type I, components Type II, mitered 6 by 4 in. injected molded reducer Bushing type 8 by 6 in. injected molded reducer Bushing type Gradual reducer type 4 by 6 in. injected molded expansion Bushing type

0.40 to 0.42 0.073 to 0.76 0.12 to 0.59 0.49 to 0.59 0.13 to 0.63 0.48 to 0.68 0.21 0.069 to 1.19 0.069 to 1.14

19.4 to 20.3 35.3 to 36.8 4.1 to 20.3 16.9 to 20.3 6.3 to 30.5 23.2 to 32.9 10.2 1.5 to 25.3 1.5 to 24.2

6 by 8 in. injected molded expansion Bushing type Gradual reducer type

0.95 to 0.96 0.94 to 0.95 0.99

32.7 to 33.0 32.4 to 32.7 34.1

Schedule 80 PVC Fitting Injected molded elbow,

Water

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Table 3.14

Test Summary for Loss Coefficients K of PVC Tees [2013F, Ch 22, Tbl 7]

Water

Branching Schedule 80 PVC Fitting 2 in. injection molded branching tee, 100% line flow 50/50 flow 100% branch flow 4 in. injection molded branching tee, 100% line flow 50/50 flow 100% branch flow 6 in. injection molded branching tee, 100% line flow 50/50 flow 100% branch flow 6 in. fabricated branching tee, 100% line flow 50/50 flow 100% branch flow 8 in. injection molded branching tee, 100% line flow 50/50 flow 100% branch flow 8 in. fabricated branching tee, 100% line flow 50/50 flow 100% branch flow Mixing PVC Fitting 2 in. injection molded mixing tee, 100% line flow 50/50 flow 100% mix flow 4 in. injection molded mixing tee, 100% line flow 50/50 flow 100% mix flow 6 in. injection molded mixing tee, 100% line flow 50/50 flow 100% mix flow 6 in. fabricated mixing tee, 100% line flow 50/50 flow 100% mix flow 8 in. injection molded mixing tee, 100% line flow 50/50 flow 100% mix flow 8 in. fabricated mixing tee, 100% line flow 50/50 flow 100% mix flow

K1-2 0.13 to 0.26 0 to 0.12 — 0.07 to 0.22 0.03 to 0.13 — 0.01 to 0.14 0.06 to 0.11 — 0.21 to 0.22 0.04 to 0.09 — 0.04 to 0.09

K1-3 — 0.74 to 1.02 0.98 to 1.39 — 0.74 to 0.82 0.97 to 1.12 — 0.70 to 0.84 0.95 to 1.15 — 1.29 to 1.40 1.74 to 1.88 —

0.04 to 0.07 — 0.09 to 0.16 0.08 to 0.13 —

0.64 to 0.75 0.85 to 0.96 — 1.07 to 1.16 1.40 to 1.62

K1-2 0.12 to 0.25 1.22 to 1.19 — 0.07 to 0.18 1.19 to 1.88 — 0.06 to 0.14 1.26 to 1.80 — 0.19 to 0.21 2.94 to 3.32 — 0.04 to 0.09 1.10 to 1.60 — 0.13 to 0.70 2.36 to 10.62 —

K3-2 — 0.89 to 1.88 0.89 to 1.54 — 0.98 to 1.88 0.88 to 1.02 — 1.02 to 1.60 0.90 to 1.07 — 2.57 to 3.17 1.72 to 1.98 — 0.96 to 1.32 0.81 to 0.93 — 2.02 to 2.67 1.34 to 1.53

Coefficients based on average velocity of 8 fps. Range of values varies with fitting manufacturers. Line or straight flow is Q2/Q1 = 100%. Branch flow is Q2/Q1 = 0%.

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04_Steam.fm Page 75 Tuesday, October 7, 2014 3:39 PM © 2013 ASHRAE (www.ashrae.org). For personal use only. Additional reproduction, distribution, or transmission in either print or digital form is not permitted without ASHRAE's prior written permission.

4.

STEAM Table 4.1

Properties of Saturated Steam Enthalpy, Btu/lb

Temperature t, °F

Specific Volume Vg, cu ft/lb

0.25 in. Hg 0.50 1.00 2.00 2 psia 3 4 5 6 7 8 9 10 12 14 14.696 20 30 40 50 60 70 80 90 100 120 140 160 180 200

40.34 58.80 79.03 101.14 126.08 141.48 152.97 162.24 170.06 176.85 182.86 188.28 193.21 201.96 209.56 212.00 227.96 250.33 267.25 281.01 292.71 302.92 312.03 320.27 327.81 341.25 353.02 363.53 373.06 381.79

2423.7 1256.4 652.3 339.2 173.7 118.7 90.63 73.52 61.98 53.64 47.34 42.40 38.42 32.40 28.04 26.80 20.09 13.75 10.50 8.515 7.175 6.206 5.472 4.896 4.432 3.728 3.220 2.834 2.532 2.228

Saturated Water hf

Evaporation hfg

Saturated Steam hg

8.28 26.86 47.05 69.10 93.99 109.37 120.86 130.13 137.94 144.76 150.79 156.22 161.17 169.96 177.61 180.07 196.16 218.82 236.03 250.09 262.09 272.61 282.02 290.56 298.40 312.44 324.82 335.93 346.03 355.36

1071.1 1060.6 1049.2 1036.6 1022.2 1013.2 1006.4 1001.0 996.2 992.1 988.5 985.2 982.1 976.6 971.9 970.3 960.1 945.3 933.7 924.0 915.5 907.9 901.1 894.7 888.8 877.9 868.2 859.2 850.8 843.0

1079.4 1087.5 1096.3 1105.7 1116.2 1122.6 1127.3 1131.1 1164.2 1136.9 1139.3 1141.4 1143.3 1146.6 1149.5 1150.4 1156.3 1164.1 1169.7 1174.1 1177.6 1180.6 1183.1 1185.3 1187.2 1190.4 1193.0 1195.1 1196.9 1198.4

Steam

Pressure p

Sources: 1. Keenan, J., and F. Keyes. 1936. Thermodynamic Properties of Steam. John Wiley and Sons, New York. 2. Holladay, W., and C. Otterholm. 1985. Numbers. Altadena, CA.

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04_Steam.fm Page 76 Tuesday, October 7, 2014 3:39 PM

Steam


Figure 4.1

Pressure-Enthalpy Diagram for Refrigerant 718 (Water/Steam) [2013F, Ch 30, Fig 19]

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1/8 psi (2 oz/in2) Sat. Press., psig 3.5 12 14 16 26 31 53 66 84 100 162 194 258 310 465 550 670 800 950 1,160 1,680 2,100 2,820 3,350 5,570 7,000 10,200 12,600 16,500 19,500

Steam

Pressure Drop per 100 ft of Length 1/4 psi (4 oz/in2) 1/2 psi (8 oz/in2) 3/4 psi (12 oz/in2) Sat. Press., psig Sat. Press., psig Sat. Press., psig 3.5 12 3.5 12 3.5 12 20 24 29 35 36 43 37 46 54 66 68 82 78 96 111 138 140 170 120 147 174 210 218 260 234 285 336 410 420 510 378 460 540 660 680 820 660 810 960 1,160 1,190 1,430 990 1,218 1,410 1,700 1,740 2,100 1,410 1,690 1,980 2,400 2,450 3,000 2,440 3,000 3,570 4,250 4,380 5,250 3,960 4,850 5,700 6,800 7,000 8,600 8,100 10,000 11,400 14,300 14,500 17,700 15,000 18,200 21,000 26,000 26,200 32,000 23,400 28,400 33,000 40,000 41,000 49,500

Flow Rate of Low-Pressure Steam in Schedule 40 Pipe

1 psi Sat. Press., psig 3.5 12 42 50 81 95 162 200 246 304 480 590 780 950 1,380 1,670 2,000 2,420 2,880 3,460 5,100 6,100 8,400 10,000 16,500 20,500 30,000 37,000 48,000 57,500

Notes: 1. Flow rate is in lb/h at initial saturation pressures of 3.5 and 12 psig. Flow is based on Moody friction factor, where the flow of condensate does not inhibit the flow of steam. 2. The flow rates at 3.5 psig cover saturated pressure from 1 to 6 psig, and the rates at 12 psig cover saturated pressure from 8 to 16 psig with an error not exceeding 8%.

Nominal 1/16 psi (1 oz/in2) Pipe Size, in. Sat. Press., psig 3.5 12 3/4 9 11 1 17 21 1-1/4 36 45 1-1/2 56 70 2 108 134 2-1/2 174 215 3 318 380 3-1/2 462 550 4 640 800 5 1,200 1,430 6 1,920 2,300 8 3,900 4,800 10 7,200 8,800 12 11,400 13,700

Table 4.2


2 psi Sat. Press., psig 3.5 12 60 73 114 137 232 280 360 430 710 850 1,150 1,370 1,950 2,400 2,950 3,450 4,200 4,900 7,500 8,600 11,900 14,200 24,000 29,500 42,700 52,000 67,800 81,000


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Table 4.3 Pipe Size (in.) 3/4 1 1 1/4 1 1/2 2 2 1/2 3 3 1/2 4 5 6 8 10 12

Pressure Drop per 100 ft 1/8 psi 1/4 psi 1/2 psi 3/4 psi 1 psi Supply Mains and Risers 25–35 psig—Max Error 8% 15 22 31 38 45 31 46 63 77 89 69 100 141 172 199 107 154 219 267 309 217 313 444 543 627 358 516 730 924 1,033 651 940 1,330 1,628 1,880 979 1,414 2,000 2,447 2,825 1,386 2,000 2,830 3,464 4,000 2,560 3,642 5,225 6,402 7,390 4,210 6,030 8,590 10,240 12,140 8,750 12,640 17,860 21,865 25,250 16,250 23,450 33,200 40,625 46,900 25,640 36,930 52,320 64,050 74,000 Return Mains and Risers 0–4 psig—Max Return Pressure 115 170 245 308 365 230 340 490 615 730 485 710 1,025 1,285 1,530 790 1,155 1,670 2,100 2,500 1,575 2,355 3,400 4,300 5,050 2,650 3,900 5,600 7,100 8,400 4,850 7,100 10,250 12,850 15,300 7,200 10,550 15,250 19,150 22,750 10,200 15,000 21,600 27,000 32,250 19,000 27,750 40,250 55,500 60,000 31,000 45,500 65,500 83,000 98,000

2 psi 63 125 281 437 886 1,460 2,660 4,000 5,660 10,460 17,180 35,100 66,350 104,500

Steam

3/4 1 1 1/4 1 1/2 2 2 1/2 3 3 1/2 4 5 6

Medium-Pressure Steam Pipe Capacities (30 psig)—Pounds Per Hour

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Table 4.4 Pipe Size (in.) 3/4 1 1 1/4 1 1/2 2 2 1/2 3 3 1/2 4 5 6 8 10 12 3/4 1 1 1/4 1 1/2 2 2 1/2 3 3 1/2 4 5 6

High-Pressure Steam Pipe Capacities (150 psig)—Pounds Per Hour

Pressure Drop per 100 ft 1/8 psi 1/4 psi 1/2 psi 3/4 psi 1 psi 2 psi 5 psi Supply Mains and Risers 130–180 psig—Max Error 8% 29 41 58 82 116 184 300 58 82 117 165 233 369 550 130 185 262 370 523 827 1,230 203 287 407 575 813 1,230 1,730 412 583 825 1,167 1,650 2,000 3,410 683 959 1,359 1,920 2,430 3,300 5,200 1,237 1,750 2,476 3,500 4,210 6,000 9,400 1,855 2,626 3,715 5,250 6,020 8,500 13,100 2,625 3,718 5,260 7,430 8,400 12,300 19,200 4,858 6,875 9,725 13,750 15,000 21,200 33,100 7,960 11,275 15,950 22,550 25,200 36,500 56,500 16,590 23,475 33,200 46,950 50,000 70,200 120,000 30,820 43,430 61,700 77,250 90,000 130,000 210,000 48,600 68,750 97,250 123,000 155,000 200,000 320,000 Return Mains and Risers 1–20 psig—Max Return Pressure 156 232 360 465 560 890 313 462 690 910 1,120 1,780 650 960 1,500 1,950 2,330 3,700 1,070 1,580 2,460 3,160 3,800 6,100 2,160 3,300 4,950 6,400 7,700 12,300 3,600 5,350 8,200 10,700 12,800 20,400 6,500 9,600 15,000 19,500 23,300 37,200 9,600 14,400 22,300 28,700 34,500 55,000 13,700 20,500 31,600 40,500 49,200 78,500 25,600 38,100 58,500 76,000 91,500 146,000 42,000 62,500 96,000 125,000 150,000 238,000

6 psi 420 790 1,720 2,600 4,820 7,600 13,500 20,000 28,000 47,500 80,000 170,000 300,000 470,000

Steam

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Riser

Return Main

3/4 1 1 1/4 1 1/2 2 2 1/2 3 3 1/2 4 5 6 3/4 1 1 1/4 1 1/2 2 2 1/2 3 3 1/2 4 5

Pipe Size, In.

1/32 psi (1/2 oz) Wet Dry Vac. – 125 62 213 130 338 206 700 470 1,180 760 1,880 1,460 2,750 1,970 3,880 2,930 48 113 248 375 750 -

Table 4.5

1/24 psi (2/3 oz) Wet Dry Vac. 42 145 71 143 248 149 244 393 236 388 810 535 815 1,580 868 1,360 2,130 1,560 2,180 3,300 2,200 3,250 4,580 3,350 4,500 7,880 12,600 48 143 113 244 248 388 375 815 750 1,360 2,180 3,250 4,480 7,880 12,600

Pressure Drop per 100 ft 1/6 psi (1 oz) 1/8 psi (2 oz) Wet Dry Vac. Wet Dry Vac. 100 142 175 80 175 250 103 249 300 168 300 425 217 426 475 265 475 675 340 674 1,000 575 1,000 1,400 740 1,420 1,680 950 1,680 2,350 1,230 2,380 2,680 1,750 2,680 3,750 2,250 3,800 4,000 2,500 4,000 5,500 3,230 5,680 5,500 3,750 5,500 7,750 4,830 7,810 9,680 13,700 15,500 22,000 48 175 48 249 113 300 113 426 248 475 248 674 375 1,000 375 1,420 750 1,680 750 2,380 2,680 3,800 4,000 5,680 5,500 7,810 9,680 13,700 15,500 22,000 1/4 psi (4 oz) Wet Dry Vac. 200 350 115 350 600 241 600 950 378 950 2,000 825 2,000 3,350 1,360 3,350 5,350 2,500 5,350 8,000 3,580 8,000 11,000 5,380 11,000 19,400 31,000 48 350 113 600 248 950 375 2,000 750 3,350 5,350 8,000 11,000 19,400 31,000

Return Main and Riser Capacities for Low-Pressure Steam Systems—Pounds per Hour

Steam


1/2 psi (8 oz) Wet Dry Vac. 283 494 848 1,340 2,830 4,730 7,560 11,300 15,500 27,300 43,800 494 848 1,340 2,830 4,730 7,560 11,300 15,500 27,300 43,800


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Pipe OD, in.

0.540

0.675

0.840

1.050

1.315

1.660

1.900

2.375

2.875

1/4

3/8

1/2

3/4

1

1 1/4

1 1/2

2

2 1/2

Piping

Nominal Size, in.

0.203 0.276

40 ST

0.218

80 XS

0.154

40 ST

0.200

80 XS

0.145

40 ST

0.191

80 XS

0.140

40 ST

0.179

80 XS

0.133

40 ST

0.154

80 XS

0.113

40 ST

0.147

80 XS

0.109

40 ST

0.126

80 XS

0.091

40 ST

0.119

80 XS

0.088

40 ST

80 XS

0.364

2.323

2.469

1.939

2.067

1.500

1.610

1.278

1.380

0.957

1.049

0.742

0.824

0.546

0.622

0.423

0.493

0.302

0.753

0.753

0.622

0.622

0.497

0.497

0.435

0.435

0.344

0.344

0.275

0.275

0.220

0.220

0.177

0.177

0.141

0.141

0.608

0.646

0.508

0.541

0.393

0.421

0.335

0.361

0.251

0.275

0.194

0.216

0.143

0.163

0.111

0.129

0.079

0.095

2.25

1.70

1.48

1.07

1.068

0.799

0.881

0.669

0.639

0.494

0.433

0.333

0.320

0.250

0.217

0.167

0.157

0.125

Metal Area, in2

4.24

4.79

2.95

3.36

1.77

2.04

1.28

1.50

0.719

0.864

0.432

0.533

0.234

0.304

0.141

0.191

0.072

0.104

Flow Area, in2

Cross Section

Steel Pipe Data

Surface Area Wall Inside Schedule Thickness Diameter Number or t, d, Outside, Inside, Weighta in. in. ft2/ft ft2/ft

Table 5.1


7.66

5.79

5.02

3.65

3.63

2.72

2.99

2.27

2.17

1.68

1.47

1.13

1.087

0.850

0.738

0.567

0.535

0.424

Pipe, lb/ft

1.83

2.07

1.28

1.45

0.765

0.881

0.555

0.647

0.311

0.374

0.187

0.231

0.101

0.131

0.061

0.083

0.031

0.045

Water, lb/ft

Weight

CW

CW

CW

CW

CW

CW

CW

CW

CW

CW

CW

CW

CW

CW

CW

CW

CW

CW

Mfr. Process

W

W

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

T

Joint Typeb

835

533

551

230

576

231

594

229

642

226

681

217

753

214

820

203

871

188

psig

Working Pressurec ASTM A53 B to 400°F

5. PIPING


81

further reprodu

Pipe OD, in.

3.500

4.500

6.625

8.625

10.75

12.75

Nominal Size, in.

3

4

6

8

10

12

Piping

0.375 0.406 0.500 0.687

40

XS

80

0.593

80

ST

0.500

XS 0.330

0.365

30

0.307

0.500

80 XS

30

0.322

40 ST

0.277

30

0.432

40 ST

0.280

40 ST

0.337

80 XS

0.237

40 ST

0.300

80 XS

0.216

40 ST

80 XS

11.376

11.750

11.938

12.000

12.090

9.564

9.750

10.020

10.136

7.625

7.981

8.071

5.761

6.065

3.826

4.026

2.900

3.068

3.338

3.338

3.338

3.338

3.338

2.814

2.814

2.814

2.814

2.258

2.258

2.258

1.734

1.734

1.178

1.178

0.916

0.916

2.978

3.076

3.125

3.141

3.165

2.504

2.552

2.623

2.654

1.996

2.089

2.113

1.508

1.588

1.002

1.054

0.759

0.803


26.03

19.24

15.74

14.58

12.88

18.92

16.10

11.91

10.07

12.76

8.40

7.26

8.40

5.58

4.41

3.17

3.02

2.23

Metal Area, in2

101.6

108.4

111.9

113.1

114.8

71.84

74.66

78.85

80.69

45.66

50.03

51.16

26.07

28.89

11.50

12.73

6.60

7.39

Flow Area, in2

Cross Section

Table 5.1 Steel Pipe Data (Continued)


88.44

65.37

53.48

49.52

43.74

64.28

54.69

40.45

34.21

43.35

28.53

24.68

28.55

18.96

14.97

10.78

10.25

7.57

Pipe, lb/ft

43.98

46.92

48.44

48.94

49.68

31.09

32.31

34.12

34.92

19.76

21.65

22.14

11.28

12.50

4.98

5.51

2.86

3.20

Water, lb/ft

Weight

ERW

ERW

ERW

ERW

ERW

ERW

ERW

ERW

ERW

ERW

ERW

ERW

ERW

ERW

CW

CW

CW

CW

Mfr. Process

W

W

W

W

W

W

W

W

W

W

W

W

W

W

W

W

W

W

Joint Typeb

1076

748

583

528

449

1081

887

606

485

1106

643

526

1209

696

695

430

767

482

psig

Working Pressurec ASTM A53 B to 400°F © 2013 ASHRAE (www.ashrae.org). For personal use only. Additional reproduction, distribution, or transmission in either print or digital form is not permitted without ASHRAE's prior written permission.

82

further reprodu

14.00

16.00

18.00

20.00

14

16

18

20 0.500 0.593

40

40

30 XS

0.500 0.562

XS 0.375

0.437

30

20 ST

0.375

ST

0.500

80

40 XS

0.750

XS 0.375

0.500

40

30 ST

0.375 0.437

30 ST

18.814

19.000

19.250

16.876

17.000

17.126

17.250

15.000

15.250

12.500

13.000

13.126

13.250

5.236

5.236

5.236

4.712

4.712

4.712

4.712

4.189

4.189

3.665

3.665

3.665

3.665

4.925

4.974

5.039

4.418

4.450

4.483

4.516

3.927

3.992

3.272

3.403

3.436

3.469


36.15

30.63

23.12

30.79

27.49

24.11

20.76

24.35

18.41

31.22

21.21

18.62

16.05

Metal Area, in2

278.0

283.5

291.0

223.7

227.0

230.3

233.7

176.7

182.6

122.7

132.7

135.3

137.9

Flow Area, in2

Cross Section

122.82

104.05

78.54

104.59

93.38

81.91

70.54

82.71

62.53

106.05

72.04

63.25

54.53

Pipe, lb/ft

120.30

122.69

125.94

96.80

98.22

99.68

101.13

76.47

79.04

53.11

57.44

58.56

59.67

Water, lb/ft

Weight

ERW

ERW

ERW

ERW

ERW

ERW

ERW

ERW

ERW

ERW

ERW

ERW

ERW

Mfr. Process

W

W

W

W

W

W

W

W

W

W

W

W

W

Joint Typeb

581

477

337

607

530

451

374

596

421

1081

681

580

481

psig

Working Pressurec ASTM A53 B to 400°F

Piping

taken as(1)12.5% of t for mill tolerance on pipe wall thickness, plus (2) An arbitrary corrosion allowance of 0.025 in. for pipe sizes through NPS 2 and 0.065 in. from NPS 2 1/2 through 20, plus (3) A thread cutting allowance for sizes through NPS 2. Because the pipe wall thickness of threaded standard pipe is so small after deducting allowance A, the mechanical strength of the pipe is impaired. It is good practice to limit standard weight threaded pipe pressure to 90 psig for steam and 125 psig for water.

aNumbers are schedule numbers per ASME Standard B36.10M; ST = Standard Weight; XS = Extra Strong. b T = Thread; W = Weld cWorking pressures were calculated per ASME B31.9 using furnace butt-weld (continuous weld, CW) pipe through 4 in. and electric resistance weld (ERW) thereafter. The allowance A has been

Pipe OD, in.

Nominal Size, in.

Table 5.1 Steel Pipe Data (Continued)



83

further reprodu

1 1/4

1

3/4

5/8

1/2

3/8

1/4

K L K L M K L M K L K L M K L M K L M DWV

0.035 0.030 0.049 0.035 0.025 0.049 0.040 0.028 0.049 0.042 0.065 0.045 0.032 0.065 0.050 0.035 0.065 0.055 0.042 0.040

Nominal Wall Diameter, Type Thickness in. t, in.

Piping

Outside D, in. 0.375 0.375 0.500 0.500 0.500 0.625 0.625 0.625 0.750 0.750 0.875 0.875 0.875 1.125 1.125 1.125 1.375 1.375 1.375 1.375

Inside d, in. 0.305 0.315 0.402 0.430 0.450 0.527 0.545 0.569 0.652 0.666 0.745 0.785 0.811 0.995 1.025 1.055 1.245 1.265 1.291 1.295

Diameter

0.098 0.098 0.131 0.131 0.131 0.164 0.164 0.164 0.196 0.196 0.229 0.229 0.229 0.295 0.295 0.295 0.360 0.360 0.360 0.360

Outside, ft2/ft 0.080 0.082 0.105 0.113 0.118 0.138 0.143 0.149 0.171 0.174 0.195 0.206 0.212 0.260 0.268 0.276 0.326 0.331 0.338 0.339

Inside, ft2/ft

Surface Area

0.037 0.033 0.069 0.051 0.037 0.089 0.074 0.053 0.108 0.093 0.165 0.117 0.085 0.216 0.169 0.120 0.268 0.228 0.176 0.168

Metal Area, in2 0.073 0.078 0.127 0.145 0.159 0.218 0.233 0.254 0.334 0.348 0.436 0.484 0.517 0.778 0.825 0.874 1.217 1.257 1.309 1.317

Flow Area, in2

Cross Section

Table 5.2 Copper Tube Data


0.145 0.126 0.269 0.198 0.145 0.344 0.285 0.203 0.418 0.362 0.641 0.455 0.328 0.839 0.654 0.464 1.037 0.884 0.682 0.650

Tube, lb/ft 0.032 0.034 0.055 0.063 0.069 0.094 0.101 0.110 0.144 0.151 0.189 0.209 0.224 0.336 0.357 0.378 0.527 0.544 0.566 0.570

Water, lb/ft

Weight

851 730 894 638 456 715 584 409 596 511 677 469 334 527 405 284 431 365 279 265

Annealed, psig

1596 1368 1676 1197 855 1341 1094 766 1117 958 1270 879 625 988 760 532 808 684 522 497

Drawn, psig

Working Pressurea,b,c ASTM B88 to 250°F © 2013 ASHRAE (www.ashrae.org). For personal use only. Additional reproduction, distribution, or transmission in either print or digital form is not permitted without ASHRAE's prior written permission.

84

further reprodu

4

3 1/2

3

2 1/2

2

K L M DWV K L M DWV K L M K L M DWV K L M K L M DWV

Piping

1 1/2

0.072 0.060 0.049 0.042 0.083 0.070 0.058 0.042 0.095 0.080 0.065 0.109 0.090 0.072 0.045 0.120 0.100 0.083 0.134 0.110 0.095 0.058


Outside D, in. 1.625 1.625 1.625 1.625 2.125 2.125 2.125 2.125 2.625 2.625 2.625 3.125 3.125 3.125 3.125 3.625 3.625 3.625 4.125 4.125 4.125 4.125

Inside d, in. 1.481 1.505 1.527 1.541 1.959 1.985 2.009 2.041 2.435 2.465 2.495 2.907 2.945 2.981 3.035 3.385 3.425 3.459 3.857 3.905 3.935 4.009

Diameter

0.425 0.425 0.425 0.425 0.556 0.556 0.556 0.556 0.687 0.687 0.687 0.818 0.818 0.818 0.818 0.949 0.949 0.949 1.080 1.080 1.080 1.080

Outside, ft2/ft 0.388 0.394 0.400 0.403 0.513 0.520 0.526 0.534 0.637 0.645 0.653 0.761 0.771 0.780 0.795 0.886 0.897 0.906 1.010 1.022 1.030 1.050

Inside, ft2/ft 0.351 0.295 0.243 0.209 0.532 0.452 0.377 0.275 0.755 0.640 0.523 1.033 0.858 0.691 0.435 1.321 1.107 0.924 1.680 1.387 1.203 0.741

Metal Area, in2 1.723 1.779 1.831 1.865 3.014 3.095 3.170 3.272 4.657 4.772 4.889 6.637 6.812 6.979 7.234 8.999 9.213 9.397 11.684 11.977 12.161 12.623

Flow Area, in2

Cross Section

Copper Tube Data (Continued)

Surface Area

Table 5.2


1.361 1.143 0.940 0.809 2.063 1.751 1.459 1.065 2.926 2.479 2.026 4.002 3.325 2.676 1.687 5.120 4.291 3.579 6.510 5.377 4.661 2.872

Tube, lb/ft 0.745 0.770 0.792 0.807 1.304 1.339 1.372 1.416 2.015 2.065 2.116 2.872 2.947 3.020 3.130 3.894 3.987 4.066 5.056 5.182 5.262 5.462

Water, lb/ft

Weight

404 337 275 236 356 300 249 180 330 278 226 318 263 210 131 302 252 209 296 243 210 128

Annealed, psig

758 631 516 442 668 573 467 338 619 521 423 596 492 394 246 566 472 392 555 456 394 240

Drawn, psig

Working Pressurea,b,c ASTM B88 to 250°F © 2013 ASHRAE (www.ashrae.org). For personal use only. Additional reproduction, distribution, or transmission in either print or digital form is not permitted without ASHRAE's prior written permission.

85

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K L M DWV K L M DWV K L M DWV K L M K L M

0.160 0.125 0.109 0.072 0.192 0.140 0.122 0.083 0.271 0.200 0.170 0.109 0.338 0.250 0.212 0.405 0.280 0.254

Outside D, in. 5.125 5.125 5.125 5.125 6.125 6.125 6.125 6.125 8.125 8.125 8.125 8.125 10.125 10.125 10.125 12.125 12.125 12.125

Inside d, in. 4.805 4.875 4.907 4.981 5.741 5.845 5.881 5.959 7.583 7.725 7.785 7.907 9.449 9.625 9.701 11.315 11.565 11.617

Diameter

1.342 1.342 1.342 1.342 1.603 1.603 1.603 1.603 2.127 2.127 2.127 2.127 2.651 2.651 2.651 3.174 3.174 3.174

Outside, ft2/ft 1.258 1.276 1.285 1.304 1.503 1.530 1.540 1.560 1.985 2.022 2.038 2.070 2.474 2.520 2.540 2.962 3.028 3.041

Inside, ft2/ft 2.496 1.963 1.718 1.143 3.579 2.632 2.301 1.575 6.687 4.979 4.249 2.745 10.392 7.756 6.602 14.912 10.419 9.473

Metal Area, in2 18.133 18.665 18.911 19.486 25.886 26.832 27.164 27.889 45.162 46.869 47.600 49.104 70.123 72.760 73.913 100.554 105.046 105.993

Flow Area, in2

Cross Section

Copper Tube Data (Continued)

Surface Area

Table 5.2

9.671 7.609 6.656 4.429 13.867 10.200 8.916 6.105 25.911 19.295 16.463 10.637 40.271 30.054 25.584 57.784 40.375 36.706

Tube, lb/ft 7.846 8.077 8.183 8.432 11.201 11.610 11.754 12.068 19.542 20.280 20.597 21.247 30.342 31.483 31.982 43.510 45.454 45.863

Water, lb/ft

Weight

285 222 194 128 286 208 182 124 304 224 191 122 304 225 191 305 211 191

Annealed, psig

534 417 364 240 536 391 341 232 570 421 358 229 571 422 358 571 395 358

Drawn, psig

Working Pressurea,b,c ASTM B88 to 250°F

cIf

using soldered or brazed fittings, the joint determines the limiting pressure. Working pressures were calculated using ASME Standard B31.9 allowable stresses. A 5% mill tolerance has been used on the wall thickness. Higher tube ratings can be calculated using the allowable stress for lower temperatures. soldered or brazed fittings are used on hard drawn tubing, use the annealed ratings. Full-tube allowable pressures can be used with suitably rated flare or compression-type fittings.

aWhen b

12

10

8

6

5


Piping



86

further reprodu

Designation

Piping

Type and Grade Thermoplastics PVC 1120 T I,G1 PVC 1200 T I,G2 PVC 2120 T II,G1 CPVC 4120 T IV,G1 PB 2110 T II,G1 PE 2306 Gr. P23 PE 3306 Gr. P34 PE 3406 Gr. P33 HDPE 3408 Gr. P34 PP Acrylonitrile ABS copolymer ABS 1210 T I,G2 ABS 1316 T I,G3 ABS 2112 T II,G1 PVDF

Material

7,000

5,500

5-2-2 3-5-5 4-4-5

6-3-3

1,275

1,600 705

2,000 1,000

8,000 4,800

5,000 5,000

2,000

1,000 1,600 1,250

2,000 2,000 2,000 2,000 1,000 630 630 630 800

Hydrostaticb Design Stress, psi (at 73°F) ASME Mfr. B31

280

176

140 212

210 180

140

180 180 180 275

150 150 150 210 210 140 160 180 180 210

640 1,000 800 306

800

320 <500

440

1.78

1.06

0.96 0.91

1.55 0.93

1.40

3.8

8.5

12 1.3

1.5

0.8

125,000

250,000 340,000

240,000

423,000 38,000 90,000 130,000 150,000 110,000 120,000

420,000 410,000

55.0 40.0 40.0 79.0

56.0

30.0 35.0 30.0 35.0 72.0 80.0 70.0 60.0 120.0 60.0

0.8

1.7

2.7 1.3

0.95 1.5

1.1

28.0

3.4

1.1 2.9

2.9 2.9

1.0

Upper Modulus Coefficient b Impact Thermal Temperature HDS of Relative of Upper Specific Strength, Conductivity, Limit, °F Elasticity, Expansion, Pipe c Limit, Gravity ft·lb/in Btu·in/ psi in/ Costd ASME psi (at 73°F) h·ft2 ·°F Mfr. (at 73°F) 106 in ·°F B31

Properties of Plastic Pipe Materialsa [2012S, Ch 46, Tbl 7]

7,500

355434-C

12454-B 12454-C 14333-D 23447-B

Cell No.

Tensile Strength, psi (at 73°F)

Table 5.3



87

further reprodu

Type and Grade

ERW Drawn

Cell No.

60,000 36,000

8,000 9,000

44,000

12,800 9,000

Hydrostaticb Design Stress, psi (at 73°F) ASME Mfr. B31

800 400

200

300

9,200 8,200

5,000

7,000

7.80 8.90

30.0

27,500,000 17,000,000

1,000,000

1,000,000

6.31 9.5

9 to 11

9 to 13

Consult the manufacturer of the system chosen. These values are for comparative purposes.

200

344

1.3

2.9

1.3 3.5

Upper Modulus Coefficient b Impact Thermal Temperature HDS of Relative of Upper Specific Strength, Conductivity, Limit, °F Elasticity, Pipe Expansion, Limit, Gravityc ft·lb/in Btu·in/ psi in/ Costd ASME 2 psi (at 73°F) h·ft ·°F Mfr. 6 (at 73°F) 10 in ·°F B31

Properties of Plastic Pipe Materialsa [2012S, Ch 46, Tbl 7] (Continued)

44,000

Tensile Strength, psi (at 73°F)

Table 5.3

a Properties listed are for specific materials listed as each plastic has other formulations. b The hydrostatic design stress (HDS) is equivalent to the allowable design stress. c Relative to water at 62.4 lb/ft3. d Based on cost of pipe only, without factoring in fittings, joints, hangers, and labor.

Thermosetting Epoxy-Glass RTRP-11AF PolyesterRTRP-12EF Glass For Comparison Steel A 53 B Copper Type L

Designation

Material

Piping



88

further reprodu

2.5 to 12 in.

XS

A53 B ERW Steel

A53 B ERW Steel

XS

A53 B ERW Steel

Standard

Standardc

Steel

SDR-11 Standardc

PB Steel (CW)

Piping

Steam and Condensate 2 in. and smaller

Standard

A53 B ERW Steel

2.5 to 12 in.

Standard Type L Sch 80 Sch 80 SDR-11

Weight

Steel (CW) Copper, hard PVC CPVC PB

Pipe Material Thread Braze or silver solderb Solvent Solvent Heat fusion Insert crimp Weld Flange Flange Flange Groove Heat fusion Thread Thread Thread Thread Thread Thread Weld Flange Flange Weld Flange Flange

Joint Type Fitting Class Material 125 Cast iron Wrought copper Sch 80 PVC Sch 80 CPVC PB Metal Standard Wrought steel 150 Wrought steel 125 Cast iron 250 Cast iron MI or ductile iron PB 125 Cast iron 150 Malleable iron 125 Cast iron 150 Malleable iron 250 Cast iron 300 Malleable iron Standard Wrought steel 150 Wrought steel 125 Cast iron XS Wrought steel 300 Wrought steel 250 Cast iron 250 250 75 150 160 160 250 250 250 250 230 160

Temperature, °F

Application of Pipe, Fittings, and Valves for Heating and Air Conditioning

Recirculating Water 2 in. and smaller

Application

Table 5.4


90 90 100 125 200 250 250 200 100 700 500 200

400 250 175 400 300

System Maximum Pressure at Temperature,a psig 125 200


89

further reprodu

Type L or K Standard

Copper, hard A53 B SML Steel

SDR-11

Copper, hard Steel, galvanized

PB

Heat fusion Insert crimp

Braze or silver solderb MJ Heat fusion Insert crimp Braze or silver solderb Thread

Braze Weld

Joint Type

125 150

MJ

Class

Wrought copper Cast iron PB Metal Wrought copper Galv. cast iron Galv. mall. iron PB Metal

Fitting Material Wrought copper Wrought steel 75 75 75 75 75 75 75 75 75

Temperature, °F

350 125 125

350 250

System Maximum Pressure at Temperature,a psig

silver solders should be used.

allowable working pressures have been derated in this table. Higher system pressures can be used for lower temperatures and smaller pipe sizes. Pipe, fittings, joints, and valves must all be con-

Type K Class 50 SDR 9, 11 SDR 7, 11.5 Type L Standard

Copper, hard Ductile iron PB

Weight

Pipe Material

Table 5.4 Application of Pipe, Fittings, and Valves for Heating and Air Conditioning (Continued)

b Lead- and antimony-based solders should not be used for potable-water systems. Brazing and cExtra-strong pipe is recommended for all threaded condensate piping to allow for corrosion.

sidered.

aMaximum

Potable Water, Inside Building

Underground Water Through 12 in. Through 6 in.

Refrigerant

Application

Piping



90

further reprodu


Table 5.5

Vacuum

Saturated Steam Pressure, psig

–14.6 –14.6 –14.5 –14.4 –14.3 –14.2 –14.0 –13.7 –13.0 –11.8 –10.0 –7.2 –3.2 0 2.5 10.3 20.7 34.6 52.3 75.0 103.3 138.3 181.1 232.6 666.1 1528 3079

Thermal Expansion of Metal Pipe

Linear Thermal Expansion, in/100 ft Temperature, Type 304 °F Carbon Steel Copper Stainless Steel –30 –0.19 –0.30 –0.32 –20 –0.12 –0.20 –0.21 –10 –0.06 –0.10 –0.11 0 0 0 0 10 0.08 0.11 0.12 20 0.15 0.22 0.24 32 0.24 0.36 0.37 40 0.30 0.45 0.45 50 0.38 0.56 0.57 60 0.46 0.67 0.68 70 0.53 0.78 0.79 80 0.61 0.90 0.90 90 0.68 1.01 1.02 100 0.76 1.12 1.13 120 0.91 1.35 1.37 140 1.06 1.57 1.59 160 1.22 1.79 1.80 180 1.37 2.02 2.05 200 1.52 2.24 2.30 212 1.62 2.38 2.43 220 1.69 2.48 2.52 240 1.85 2.71 2.76 260 2.02 2.94 2.99 280 2.18 3.17 3.22 300 2.35 3.40 3.46 320 2.53 3.64 3.70 340 2.70 3.88 3.94 360 2.88 4.11 4.18 380 3.05 4.35 4.42 400 3.23 4.59 4.87 500 4.15 5.80 5.91 600 5.13 7.03 7.18 700 6.16 8.29 8.47 800 7.23 9.59 9.79 900 8.34 10.91 11.16 1000 9.42 12.27 12.54 Piping

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Table 5.6 NPS, in. 1/2 3/4 1 1 1/2 2 2 1/2 3 4 6 8 10 12 14 16 18 20

Suggested Hanger Spacing and Rod Size for Straight Horizontal Runs Hanger Spacing, ft Standard Steel Pipe* Water Steam 7 8 7 9 7 9 9 12 10 13 11 14 12 15 14 17 17 21 19 24 20 26 23 30 25 27 28 30

32 35 37 39

Copper Tube Water 5 5 6 8 8 9 10 12 14 16 18 19

Rod Size, in. 1/4 1/4 1/4 3/8 3/8 3/8 3/8 1/2 1/2 5/8 3/4 7/8 1 1 1 1/4 1 1/4

Source: Adapted from MSS Standard SP-69 *Spacing does not apply where span calculations are made or where concentrated loads are placed between supports such as flanges, valves, specialties, etc.

Table 5.7 Rod Diameter, in. 1/4 3/8 1/2 5/8 3/4 7/8 1 1 1/4

Capacities of ASTM A36 Steel Threaded Rods Root Area of Coarse Thread, in2 0.027 0.068 0.126 0.202 0.302 0.419 0.552 0.889

Maximum Load,* lb 240 610 1130 1810 2710 3770 4960 8000

Piping

*Based on an allowable stress of 12,000 psi reduced by 25% using the root area in accordance with ASME Standard B31.1 and MSS Standard SP-58.

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6.

SERVICE WATER HEATING Service Water Heating

Water heating energy use is second only to space conditioning in most residential buildings, and is also significant in many commercial and industrial settings. In some climates and applications, water heating is the largest energy use in a building. Moreover, quick availability of adequate amounts of hot water is an important factor in user satisfaction. Both water and energy waste can be significant in poorly designed service water-heating systems: from over- or undersizing pipes and equipment, from poor building layout, and from poor system design and operating strategies. Good service water-heating system design and operating practices can often reduce first costs as well as operating costs.

System Elements A service water-heating system has (1) one or more heat energy sources, (2) heat transfer equipment, (3) a distribution system, and (4) terminal hot-water usage devices. Heat energy sources may be (1) fuel combustion; (2) electrical conversion; (3) solar energy; (4) geothermal, air, or other environmental energy; and/or (5) recovered waste heat from sources such as flue gases, ventilation and air-conditioning systems, refrigeration cycles, and process waste discharge. Heat transfer equipment is direct, indirect, or a combination of the two. For direct equipment, heat is derived from combustion of fuel or direct conversion of electrical energy into heat and is applied within the water-heating equipment. For indirect heat transfer equipment, heat energy is developed from remote heat sources (e.g., boilers; solar energy collection; air, geothermal, or other environmental source; cogeneration; refrigeration; waste heat) and is then transferred to the water in a separate piece of equipment. Storage tanks may be part of or associated with either type of heat transfer equipment. Distribution systems transport hot water produced by water-heating equipment to terminal hot-water usage devices. Water consumed must be replenished from the building water service main. For locations where constant supply temperatures are desired, circulation piping or a means of heat maintenance must be provided. Terminal hot-water usage devices are plumbing fixtures and equipment requiring hot water that may have periods of irregular flow, constant flow, and no flow. These patterns and their related water usage vary with different buildings, process applications, and personal preference.

Legionella pneumophila (Legionnaires’ Disease) Legionnaires’ disease (a form of severe pneumonia) is caused by inhaling the bacteria Legionella pneumophila. It has been discovered in the service water systems of various buildings throughout the world. Service water temperature in the 140°F range is recommended to limit the potential for L. pneumophila growth. This high temperature increases the potential for scalding, so care must be taken such as installing an anti-scald or mixing valve. More information on this subject can be found in ASHRAE Guideline 12-2000.

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Service Water Heating

Load Diversity The greatest difficulty in designing water-heating systems comes from uncertainty about design hot-water loads, especially for buildings not yet built. Although it is fairly simple to test maximum flow rates of various hot-water fixtures and appliances, actual flow rates and durations are user-dependent. Moreover, the timing of different hot-water use events varies from day to day, with some overlap, but almost never will all fixtures be used simultaneously. As the number of hot-water-using fixtures and appliances grows, the percent of those fixtures used simultaneously decreases. Some of the hot-water load information here is based on limited-scale field testing combined with statistical analysis to estimate load demand or diversity factors (percent of total possible load that is ever actually used at one time) versus number of end use points, number of people, etc. Much of the work to provide these diversity factors dates from the 1930s to the 1960s; it remains, however, the best information currently available (with a few exceptions, as noted). Of greatest concern is the fact that most of the data from those early studies were for fixtures that used water at much higher flow rates than modern energy-efficient fixtures (e.g., low-flow shower heads and sink aerators, energy-efficient washing machines and dishwashers). Using the older load diversity information usually results in a water-heating system that adequately serves the loads, but often results in substantial oversizing. Oversizing can be a deterrent to using modern high-efficiency water-heating equipment, which may have higher first cost per unit of capacity than less efficient equipment. Table 6.1 Typical Residential Use of Hot Water [2011A, Ch 50, Tbl 4] Use Food preparation Hand dish washing Automatic dishwasher Clothes washer Shower or bath Face and hand washing

High Flow, Gallons/Task 5 4 15 32 20 4

Low Flow (Water Savers Used), Gallons/Task 3 4 15 21 15 2

Ultralow Flow, Gallons/Task 3 3 3 to 10 5 to 15 10 to 15 1 to 2

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Table 6.2 HUD-FHA Minimum Water Heater Capacities for One- and Two-Family Living Units [2011A, Ch 50, Tbl 5]

1

1 to 1.5 2 3

2

2 to 2.5 3 4

5

3

3 to 3.5 4 5

6 50 50 92 42

20 27 43 23

30 36 60 30

30 36 60 30

30 36 60 30

40 36 70 30

40 38 72 32

50 47 90 40

40 38 72 32

50 38 82 32

50 47 90 40

20 2.5 30 10

30 3.5 44 14

40 4.5 58 18

40 4.5 58 18

50 5.5 72 22

50 5.5 72 22

66 5.5 88 22

50 5.5 72 22

66 5.5 88 22

66 80 5.5 5.5 88 102 22 22

30 70 89 59

30 70 89 59

30 70 89 59

30 70 89 59

30 70 89 59

30 70 89 59

30 70 89 59

30 70 89 59

30 70 89 59

30 70 89 59

30 70 89 59

40

40

66

66e

66

66

66

66

66

49

49

75

75e

75

75

75

75

75

66

e

82

66

82

82

82

66

66

2.75 2.75 15

15

66


Number of Baths Number of Bedrooms Gasa Storage, gal 1000 Btu/h input 1 h draw, gal Recovery, gph Electric a Storage, gal kW input 1 h draw, gal Recovery, gph a Oil Storage, gal 1000 Btu/h input 1 h draw, gal Recovery, gph Tank-Type Indirect b,c I-W-H-rated draw, gal in 3 h, 100°F rise Manufacturer-rated draw, gal in 3 h, 100°F rise Tank capacity, gal Tankless-Type Indirectc,d I-W-H-rated draw, gpm, 100°F rise Manufacturer-rated draw, gal in 5 min, 100°F rise

3.25 3.25e 3.75 3.25 3.75 3.75 3.75 25

25e

35

25

35

35

35

.

Note: Applies to tank-type water heaters only aStorage capacity, input, and recovery requirements indicated are typical and may vary with manufacturer. Any combination of requirements to produce stated 1 h draw is satisfactory. b Boiler-connected water heater capacities (180°F boiler water, internal or external connection). cHeater capacities and inputs are minimum allowable. Variations in tank size are permitted when recovery is based on 4 gph/kW at 100°F rise for electrical, AGA recovery ratings for gas, and IBR ratings for steam and hot-water heaters. dBoiler-connected heater capacities (200°F boiler water, internal or external connection). eAlso for 1 to 1.5 baths and 4 bedrooms for indirect water heaters.

Table 6.3

Overall (OVL) and Peak Average Hot-Water Use [2011A, Ch 50, Tbl 6]

Group All families “Typical” families

Hourly OVL Peak 2.6 4.6 2.6 5.8

Average Hot-Water Use, gal Daily Weekly OVL Peak OVL Peak 62.4 67.1 436 495 63.1 66.6 442 528

Monthly OVL Peak 1897 2034 1921 2078

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Table 6.4

Hot-Water Demands and Use for Various Types of Buildings* [2011A, Ch 50, Tbl 7]

Type of Building Maximum Hourly Men’s dormitories 3.8 gal/student Women’s dormitories 5.0 gal/student Motels: Number of unitsa 20 or less 6.0 gal/unit 60 5.0 gal/unit 100 or more 4.0 gal/unit Nursing homes 4.5 gal/bed Office buildings 0.4 gal/person Food service establishments Type A: Full-meal restaurants 1.5 gal/max meals/ and cafeterias h Type B: Drive-ins, grills, 0.7 gal/max meals/ luncheonettes, sandwich, and h snack shops Apartment houses: Number of apartments 20 or less 12.0 gal/apartment 50 10.0 gal/apartment 75 8.5 gal/apartment 100 7.0 gal/apartment 200 or more 5.0 gal/apartment Elementary schools 0.6 gal/student Junior and senior high schools 1.0 gal/student

Maximum Daily 22.0 gal/student 26.5 gal/student

Average Daily 13.1 gal/student 12.3 gal/student

35.0 gal/unit 25.0 gal/unit 15.0 gal/unit 30.0 gal/bed 2.0 gal/person

20.0 gal/unit 14.0 gal/unit 10.0 gal/unit 18.4 gal/bed 1.0 gal/person

11.0 gal/max meals/day

2.4 gal/average meals/dayb

6.0 gal/max meals/ day

0.7 gal/average meals/dayb

80.0 gal/apartment 73.0 gal/apartment 66.0 gal/apartment 60.0 gal/apartment 50.0 gal/apartment 1.5 gal/student 3.6 gal/student

42.0 gal/apartment 40.0 gal/apartment 38.0 gal/apartment 37.0 gal/apartment 35.0 gal/apartment 0.6 gal/studentb 1.8 gal/studentb

*Data predate modern low-flow fixtures and appliances. a Interpolate for intermediate values.bPer day of operation.

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Basin, private lavatory Basin, public lavatory Bathtubc Dishwashera Foot basin Kitchen sink Laundry, stationary tub Pantry sink Shower Service sink Hydrotherapeutic shower Hubbard bath Leg bath Arm bath Sitz bath Continuous-flow bath Circular wash sink Semicircular wash sink DEMAND FACTOR STORAGE CAPACITY FACTORb

2 6 20 50-150 3 20 28 10 150 20

0.30 0.90

0.30

1.25

Club

Apartment House 2 4 20 15 3 10 20 5 30 20

1.00

0.40

2 8 30 — 12 — — — 225 —

Gymnasium

0.60

2 6 20 50-150 3 20 28 10 75 20 400 600 100 35 30 165 20 10 0.25

Hospital

2.00

20 10 0.30

Office Building 2 6 — — — 20 — 10 30 20

0.70

0.30

Private Residence 2 — 20 15 3 10 20 5 30 15

1.00

30 15 0.40

2 15 — 20-100 3 20 — 10 225 20

School

1.00

0.40

2 8 30 20-100 12 20 28 10 225 20

YMCA

of steam is available from central street steam system or large boiler plant.

1.00

30 15 0.40

20 10 0.25 0.80

Industrial Plant 2 12 — 20-100 12 20 — — 225 20

2 8 20 50-200 3 30 28 10 75 30

Hotel

a Dishwasher requirements should be taken from this table or from manufacturers’ data for model to be used, if known. bRatio of storage tank capacity to probable maximum demand/h. Storage capacity may be reduced where unlimited supply cWhirlpool baths require specific consideration based on capacity. They are not included in the bathtub category.

Note: Data sources predate low-flow fixtures and appliances.

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20.

Table 6.5 Hot-Water Demand per Fixture for Various Types of Buildings [2011A, Ch 50, Tbl 10] (Gallons of water per hour per fixture, calculated at a final temperature of 140°F)




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Table 6.6 Service Water Heating

Flow Rate, gpm 0.1 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 6.0 7.0 8.0 9.0 10.0

Tankless Water Heater Output Heat Rates, Btu/h* [2011A, Ch 50, Tbl 15] Temperature Rise 10°F

25°F

50°F

55°F

75°F

77°F

100°F

504 2,520 5,040 7,560 10,080 12,600 15,120 17,640 20,160 22,680 25,200 30,240 35,280 40,320 45,360 50,400

1,260 6,300 12,600 18,900 25,200 31,500 37,800 44,100 50,400 56,700 63,000 75,600 88,200 100,800 113,400 126,000

2,520 12,600 25,200 37,800 50,400 63,000 75,600 88,200 100,800 113,400 126,000 151,200 176,400 201,600 226,800 252,000

2,772 13,860 27,720 41,580 55,440 69,300 83,160 97,020 110,880 124,740 138,600 166,320 194,040 221,760 249,480 277,200

3,780 18,900 37,800 56,700 75,600 94,500 113,400 132,300 151,200 170,100 189,000 226,800 264,600 302,400 340,200 378,000

3,881 19,404 38,808 58,212 776,196 97,020 116,424 135,828 155,232 174,636 194,040 232,848 271,656 310,464 349,272 388,080

5,040 25,200 50,400 75,600 100,800 126,000 151,200 176,400 201,600 226,800 252,000 302,400 352,800 403,200 453,600 504,000

*Divide table values by input efficiency to determine required heat input rate.

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0.75 — 1.5 1.5 — 0.75 — 1.5 1.5 — —

Gymnasium

Hospital

0.75 0.75 0.75 1 1 1 1.5 — 1.5 Five fixture units per 250 seating capacity — — 5 1.5 — 3 2.5 — 2.5 2.5 — 2.5 1.5 1.5 1.5 2.5 2.5 2.5 1.5 1.5 1.5

Club

Industrial Plant 0.75 1 — — 3 — 2.5 3.5 4 3

Hotels and Dormitories 0.75 1 1.5 — 1.5 2.5 2.5 1.5 — —

— — — 2.5 — — —

Office Building 0.75 1 —

Hot-Water Demand in Fixture Units (140°F Water) [2011A, Ch 50, Tbl 16]

Note: Data predate modern low-flow fixtures and appliances.

Basin, private lavatory Basin, public lavatory Bathtub Dishwasher* Therapeutic bath Kitchen sink Pantry sink Service sink Shower Circular wash fountain Semicircular wash fountain

Apartments

Table 6.7

— 0.75 2.5 2.5 1.5 2.5 1.5

0.75 1 —

School

— 3 2.5 2.5 1.5 2.5 1.5

0.75 1 —

YMCA




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Figure 6.1 Modified Hunter Curve for Calculating Hot-Water Flow Rate [2011A, Ch 50, Fig 25] (Data Predate Modern Low-Flow Fixtures and Appliances)

Figure 6.2 Enlarged Section of Modified Hunter Curve [2011A, Ch 50, Fig 26] (Data Predate Modern Low-Flow Fixtures and Appliances) 100

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7.

SOLAR ENERGY USE

Solar Energy Use

ti ta It UL  



FR

= = = = = = = =

average fluid temperature, °F ambient air temperature, °F incident normal radiation, plus diffuse radiation, °F·ft2 ·h/Btu overall heat loss coefficient absorptivity FR, –FRUL(t1 – ta)/t = efficiency fraction of solar radiation reaching collector collector heat removal factor

Figure 7.1 Typical Use Ranges and Efficiencies of Various Liquid Solar Collectors

Table 7.1

7 Jan 21 0 Jul 21 114 Jan 21 10 24º N Latitude Jul 21 98 40º N Latitude

Total Insolation

Btu/h·ft2 on Horizontal Surface, Sun Time 8 9 10 11 12 1 2 3 4 28 83 127 154 164 154 127 83 28 174 225 265 290 298 290 265 225 174 83 151 204 237 249 237 204 151 83 169 231 278 307 317 307 278 231 169

5 0 114 10 98 101

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Solar Energy Use


Figure 7.2 Variation with Solar Altitude and Time of Year for Direct Normal Irradiation [2011A, Ch 35, Fig 4]

Figure 7.3 Total Daily Irradiation for Horizontal, Tilted, and Vertical Surfaces at 40° North Latitude (± LAT Figures are Degrees of Tilt Above or Below Latitude) [2011A, Ch 35, Fig 6] 102

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Table 7.2 Thermal Performance Ratings* for Generic Types of Liquid Flat-Plate Collectors [2012S, Ch 37, Tbl 3]

Category*

Selective surface A B C D E Evacuated tube A B C D E *Categories A B C D E

1600 1000 400 — —

1200 700 200 — —

900 400 — — —

1285 1128 908 407 —

971 815 595 157 —

658 533 282 — —

1316 1191 1003 595 219

971 877 689 313 31

658 564 376 63 —

872 841 810 685 592 Ti – Ta , °F –9 9 36 90 144

Solar Energy Use

Unglazed A B C D E Painted A B C D E

Solar Day, Btu/ft2 ·day 2000 1500 1000 (Clear Day) (Mildly Cloudy) (Cloudy Day)

655 436 623 405 592 374 467 280 374 156 Application Pool heating, warm climate Pool heating, cool climate Water heating, warm climate Water heating, cool climate Air conditioning

*Derived from data of Solar Rating and Certification Corporation (SRCC), www.solar-rating.org (Oct. 2006).

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Solar Energy Use


Figure 7.4

Figure 7.5

Liquid-Based Solar Heating System [2012A, Ch 33, Fig 27]

Solar Air and Service Water Heating System [2012A, Ch 33, Fig 28] (Adapted from Beckman et al. 1977)

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Solar Energy Use

Figure 7.6 Solar Collection, Storage, and Distribution System for Domestic Hot Water and Space Heating [2012A, Ch 33, Fig 25]

Figure 7.7 Space Heating and Cooling System Using Lithium Bromide-Water Absorption Chiller [2012A, Ch 33, Fig 26] Concentrating collector desirable, water temperature >190°F 105

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8.

REFRIGERATION CYCLES

Refrigeration cycles transfer thermal energy from a region of low temperature TR to one of higher temperature. Usually the higher-temperature heat sink is the ambient air or cooling water, at temperature T0 , the temperature of the surroundings. The first and second laws of thermodynamics can be applied to individual components to determine mass and energy balances and the irreversibility of the components. This procedure is illustrated in later sections in this chapter. Performance of a refrigeration cycle is usually described by a coefficient of performance (COP), defined as the benefit of the cycle (amount of heat removed) divided by the required energy input to operate the cycle: Useful refrigerating effect COP  ----------------------------------------------------------------------------------------------------Net energy supplied from external sources For a mechanical vapor compression system, the net energy supplied is usually in the form of work, mechanical or electrical, and may include work to the compressor and fans or pumps. Thus, Q evap COP = --------------W net

Refrigeration Cycles

In an absorption refrigeration cycle, the net energy supplied is usually in the form of heat into the generator and work into the pumps and fans, or Q evap COP = ------------------------------Q gen + W net In many cases, work supplied to an absorption system is very small compared to the amount of heat supplied to the generator, so the work term is often neglected. Applying the second law to an entire refrigeration cycle shows that a completely reversible cycle operating under the same conditions has the maximum possible COP. Departure of the actual cycle from an ideal reversible cycle is given by the refrigerating efficiency: COP  R = ---------------------- COP  rev

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Figure 8.1 Theoretical Single-Stage Vapor Compression Refrigeration Cycle

Heat into evaporator 4Q1 = m(h1 – h4) Btu/min Work of compression 1W2 = m(h2 – h1) with s = constant Btu/min Heat out to condenser 2Q3 = m(h2 – h3) Btu/min Expansion by throttling flow h3 = h4 Coefficient of performance where m = h = s =

h1 – h4 4Q1 COP = ---------- = ----------------h2 – h1 1W2

refrigerant flow rate, lb/min enthalpy, Btu/lb entropy, Btu/lb·°R

Theoretical compressor displacement, D = m v1 ft3/min where v1 = specific volume at suction, ft3/lb. For a given cycle, capacity in tons of refrigeration:  tons   200 Btu  min – ton  m = ---------------------------------------------------------------------h 1 – h4 107

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There are pressure drops in evaporator, condenser, and piping. There is power input to evaporator and condenser. There are heat gains and losses between refrigerant and environment. The liquid is subcooled; the suction vapor is superheated.

Figure 8.2

Schematic of Real, Direct-Expansion, Single-Stage Mechanical Vapor-Compression Refrigeration System [2013F, Ch 2, Fig 14]

Figure 8.3 Pressure-Enthalpy Diagram of Actual System and Theoretical Single-Stage System Operating Between Same Inlet Air Temperatures tR and t0 [2013F, Ch 2, Fig 15] 108

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Absorption Refrigeration Absorption refrigeration uses heat as the major energy input rather than electrical or mechanical energy to drive the cycle. Use of waste heat can make absorption refrigeration more economically attractive. The equipment can be broadly categorized by whether it uses water or ammonia as refrigerant. The primary products in the water refrigerant category are large commercial chillers, which use lithium bromide (LiBr) as absorbent. There are three primary products in the ammonia refrigerant category: (1) domestic refrigerators, (2) residential chillers, and (3) large industrial refrigeration units.


Figure 8.4 Similarities Between Absorption and Vapor Compression Systems [2010R, Ch 18, Fig 1]

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Table 8.1 Characteristics of Typical Indirect-Fired, Water-Lithium Bromide Absorption Chiller

Steam input pressure Steam consumption Hot fluid input temp. Heat input rate Cooling water temp. in Cooling water flow Chilled water temp. off Chilled water flow Electric power


Nominal capacities

Table 8.2

Single Effect 9 to 12 psig 18.3 to 18.7 lb/ton·h 240 to 270°F, with as low as 190°Ffor some smaller machines for waste heat applications 18,100 to 18,500 Btu/ton·h, with as low as 17,100 Btu/ton·hfor some smaller machines 85°F 3.6 gpm/ton, with up to 6.4 gpm/ton for some smaller machines 44°F 2.4 gpm/ton, with 2.6 gpm/ton for some smaller international machines 0.01 to 0.04 kW/ton with a minimum of 0.004 kW/tonfor some smaller machines 50 to 1660 tons, with 5 to 10 tons for some smaller machines

Double Effect 115 psig 9.7 to 10 lb/ton·h 370°F 10,000 Btu/ton·h 85°F 3.6 to 4.5 gpm/ton 44°F 2.4 gpm/ton 0.01 to 0.04 kW/ton 100 to 1700 tons

Characteristics of Typical Double-Effect, Direct-Fired, Water-Lithium Bromide Absorption Chiller

Performance Characteristics Fuel consumption (high heating value of fuel) 12,000 to 13,044 Btu/ton·h COP (high heating value) 0.92 to 1.0 Cooling water temperature in 85°F Cooling water flow 4.4 to 4.5 gpm/ton Chilled water temperature off 44°F Chilled water flow 2.4 gpm/ton Electric power 0.01 to 0.04 kW/ton Nominal capacities 100 to 1500 tons

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9.

REFRIGERANTS

Refrigerant Data Table 9.1 Refrigerant

Refrigerant Data

Chemical Formula

Molecular Mass

Normal Boiling Point °C

°F

Safety Grou p

Halogenated Hydrocarbons CFCs (no longer manufactured) R-11

CCl3F

137.4

24

75

A1

R-12

CCl2F2

120.9

–30

–22

A1

R-113

CCl2FCClF2

167.4

48

118

A1

R-114

CClF2CClF2

170.9

4

38

A1

HCFCs (phasing out) R-22

CHClF2

86.5

–41

–41

A1

R-123

CHCl2CF3

153.0

27

81

B1

HFCs R-32

CH2F2

52.0

–52

–62

A2

R-125

CHF2CF3

120.0

–49

–56

A1

R-134a

CH2FCF3

102.0

–26

–15

A1

R-143a

CH3CF3

66.0

–47

–53

A2

Hydrocarbons R-290 (propane)

CH3CH2CH3

44.0

–42

–44

A3

CH(CH3)2CH3

58.1

–12

11

A3

R-717 (ammonia)

NH3

17

–33

–28

B2

R-718 (water)

H2O

18

100

212

A1

(mix approx 79% N2, 21% O2)

29

CO2

44

–78

–109

A1

R-404A

(R-125, R-143a, R-134a) (44/52/4)

97.6

–47

–52

A1

R-407C

(R-32, R-125, R-134a) (23/25/52)

86.2

–43

–46

A1

R-410A

(R-32, R-125) (50/50)

72.6

–52

–61

A1

(R-125, R-143a) (50/50)

98.9

–46.7

–52.1

A1

R-600a (isobutane) Natural Refrigerants

R-729 (air)

A1

Zeotropic Blends

Refrigerants

R-744 (carbon dioxide)

Azeotropic Blend R-507A

Usual lubricants: (1) Mineral oils (MO) – CFCs, HCFCs (2) Alkyl benzenes (AB) – HCFCs (3) Polyol esters (POE) – HCFCs, HFCs, blends The environmental effect of the chlorine in CFCs and HCFCs has resulted in CFCs no longer being manufactured and the manufacture of HCFCs being phased out. 111

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Refrigerants


Figure 9.1 Refrigerant 22 (Chlorodifluoromethane) Properties of Saturated Liquid and Saturated Vapor [2013F, Ch 30, Fig 2]

112

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Table 9.2

Temp.,* °F

Pressure, psia

R-22 (Chlorodifluoromethane) Properties of Saturated Liquid and Saturated Vapor [2013F, Ch 30, Tbl R-22] Density, lb/ft3 Liquid 98.28 97.36 96.44 95.52 94.59 93.66 93.19 92.71 92.24 91.76 91.28 90.79 90.31 89.82 89.33 88.83 88.33 87.97 87.82 87.32 86.80 86.29 85.76 85.24 84.71 84.17 83.63 83.08 82.52 81.96 81.39 80.82 80.24 79.65 79.05 78.44 77.83 77.20 76.57 75.92 75.27 74.60 73.92 73.23 72.52 71.80 71.06 70.30 69.52 68.72 67.90 67.05 66.18 65.27 64.32 63.34 62.31 61.22 60.07 58.84 57.53 56.10 54.52 52.74 50.67 48.14 44.68 32.70

Enthalpy, Btu/lb Liquid

Vapor

146.06 –28.119 87.566 90.759 –25.583 88.729 58.384 –23.046 89.899 38.745 –20.509 91.074 26.444 –17.970 92.252 18.511 –15.427 93.430 15.623 –14.154 94.018 13.258 –12.880 94.605 11.309 –11.604 95.191 9.6939 –10.326 95.775 8.3487 –9.046 96.357 7.2222 –7.763 96.937 6.2744 –6.477 97.514 5.4730 –5.189 98.087 4.7924 –3.897 98.657 4.2119 –2.602 99.224 3.7147 –1.303 99.786 3.4054 –0.381 100.181 3.2872 0.000 100.343 2.9181 1.308 100.896 2.5984 2.620 101.443 2.3204 3.937 101.984 2.0778 5.260 102.519 1.8656 6.588 103.048 1.6792 7.923 103.570 1.5150 9.263 104.085 1.3701 10.610 104.591 1.2417 11.964 105.090 1.1276 13.325 105.580 1.0261 14.694 106.061 0.9354 16.070 106.532 0.8543 17.455 106.994 0.7815 18.848 107.445 0.7161 20.250 107.884 0.6572 21.662 108.313 0.6040 23.083 108.729 0.5558 24.514 109.132 0.5122 25.956 109.521 0.4725 27.409 109.897 0.4364 28.874 110.257 0.4035 30.350 110.602 0.3734 31.839 110.929 0.3459 33.342 111.239 0.3207 34.859 111.530 0.2975 36.391 111.801 0.2762 37.938 112.050 0.2566 39.502 112.276 0.2385 41.084 112.478 0.2217 42.686 112.653 0.2062 44.308 112.799 0.1918 45.952 112.914 0.1785 47.621 112.996 0.1660 49.316 113.040 0.1544 51.041 113.043 0.1435 52.798 113.000 0.1334 54.591 112.907 0.1238 56.425 112.756 0.1149 58.305 112.539 0.1064 60.240 112.247 0.0984 62.237 111.866 0.0907 64.309 111.378 0.0834 66.474 110.760 0.0764 68.757 109.976 0.0695 71.196 108.972 0.0626 73.859 107.654 0.0556 76.875 105.835 0.0479 80.593 103.010 0.0306 91.208 91.208 b Normal boiling point

Entropy, Btu/lb·°F Liquid

Vapor

–0.07757 –0.06951 –0.06170 –0.05412 –0.04675 –0.03959 –0.03608 –0.03261 –0.02918 –0.02580 –0.02245 –0.01915 –0.01587 –0.01264 –0.00943 –0.00626 –0.00311 –0.00091 0.00000 0.00309 0.00615 0.00918 0.01220 0.01519 0.01815 0.02110 0.02403 0.02694 0.02983 0.03270 0.03556 0.03841 0.04124 0.04406 0.04686 0.04966 0.05244 0.05522 0.05798 0.06074 0.06350 0.06625 0.06899 0.07173 0.07447 0.07721 0.07996 0.08270 0.08545 0.08821 0.09098 0.09376 0.09656 0.09937 0.10222 0.10509 0.10800 0.11096 0.11397 0.11705 0.12022 0.12350 0.12693 0.13056 0.13450 0.13893 0.14437 0.16012 c Critical point

0.29600 0.28808 0.28090 0.27439 0.26846 0.26307 0.26055 0.25815 0.25585 0.25366 0.25155 0.24954 0.24761 0.24577 0.24400 0.24230 0.24067 0.23955 0.23910 0.23759 0.23615 0.23475 0.23341 0.23211 0.23086 0.22965 0.22848 0.22735 0.22625 0.22519 0.22415 0.22315 0.22217 0.22121 0.22028 0.21936 0.21847 0.21758 0.21672 0.21586 0.21501 0.21417 0.21333 0.21250 0.21166 0.21083 0.20998 0.20913 0.20827 0.20739 0.20649 0.20557 0.20462 0.20364 0.20261 0.20153 0.20040 0.19919 0.19790 0.19650 0.19497 0.19328 0.19136 0.18916 0.18651 0.18316 0.17835 0.16012

Refrigerants

–150 0.263 –140 0.436 –130 0.698 –120 1.082 –110 1.629 –100 2.388 –95 2.865 –90 3.417 –85 4.053 –80 4.782 –75 5.615 –70 6.561 –65 7.631 –60 8.836 –55 10.190 –50 11.703 –45 13.390 b –41.46 14.696 –40 15.262 –35 17.336 –30 19.624 –25 22.142 –20 24.906 –15 27.929 –10 31.230 –5 34.824 0 38.728 5 42.960 10 47.536 15 52.475 20 57.795 25 63.514 30 69.651 35 76.225 40 83.255 45 90.761 50 98.763 55 107.28 60 116.33 65 125.94 70 136.13 75 146.92 80 158.33 85 170.38 90 183.09 95 196.50 100 210.61 105 225.46 110 241.06 115 257.45 120 274.65 125 292.69 130 311.58 135 331.37 140 352.08 145 373.74 150 396.38 155 420.04 160 444.75 165 470.56 170 497.50 175 525.62 180 554.98 185 585.63 190 617.64 195 651.12 200 686.20 205.06c 723.74 *Temperatures on ITS-90 scale

Volume, ft3/lb Vapor

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Table 9.3 Temp., °F 10 30 60 100 150 Temp., °F 30 60 100 150 Temp., °F 100 150 200 250 300 Temp., °F

Refrigerants

100 150 200 250 300 Temp., °F 150 200 250 300

Superheated Vapor Thermodynamic Properties of R-22

Pressure = 30 psia Sat. Temp. = 11.85°F V h s 1.760 103.92 0.2325 1.943 109.92 0.2453 2.078 114.55 0.2545 2.255 120.92 0.2663 2.473 129.17 0.2804 Pressure = 75 psia Sat. Temp. = 34.06°F V h s 0.7851 107.81 0.2229 0.7847 112.45 0.2306 0.8639 119.13 0.2429 0.9591 127.69 0.2576 Pressure = 135 psia Sat. Temp. = 69.39°F V h s 0.4492 116.50 0.2260 0.5092 125.59 0.2416 0.5655 134.79 0.2561 0.6193 144.20 0.2698 0.6713 153.84 0.2829 Pressure = 200 psia Sat. Temp. = 96.17°F V h s 0.2776 113.22 0.2126 0.3251 123.11 0.2295 0.3674 132.83 0.2448 0.4067 142.60 0.2591 0.4441 152.52 0.2726 Pressure = 240 psia Sat. Temp. = 109.57°F V h s 0.2606 121.45 0.2232 0.2985 131.56 0.2392 0.3330 141.58 0.2538 0.3654 151.69 0.2676

Pressure = 60 psia Sat. Temp. = 21.94°F V h s 0.9271 1.001 1.096 1.212

108.35 0.2271 113.17 0.2367 119.74 0.2488 128.19 0.2633 Pressure = 90 psia Sat. Temp. = 44.47°F V h s

0.6401 111.69 0.2253 0.7088 118.50 0.2379 0.7906 127.18 0.2528 Pressure = 180 psia Sat. Temp. = 88.72°F V h s 0.3177 114.29 0.2164 0.3678 123.90 0.2329 0.4132 133.45 0.2479 0.4558 143.10 0.2620 0.4965 152.93 0.2754 Pressure = 220 psia Sat. Temp. = 103.09°F V h s 0.2900 122.30 0.2263 0.3299 132.20 0.2419 0.3666 142.09 0.2564 0.4012 152.10 0.2700 Pressure = 260 psia Sat. Temp. = 115.66°F V h s 0.2356 120.58 0.2203 0.2720 130.90 0.2366 0.3046 141.06 0.2514 0.3351 151.27 0.2653

V = vapor volume, ft3/lb h = enthalpy, Btu/lb s = entropy, Btu/lb°F

114

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Refrigerants

Figure 9.2 Pressure-Enthalpy Diagram for Refrigerant 123 [2013F, Ch 30, Fig 5]

115

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Table 9.4 R-123 (2,2-Dichloro-1,1,1-Trifluoroethane) Properties of Saturated Liquid and Saturated Vapor [2013F, Ch 30, Tbl R-123] Density, lb/ft3 Liquid

Volume, ft3/lb Vapor

–140 0.003 108.90 –130 0.006 108.12 –120 0.011 107.35 –110 0.020 106.57 –100 0.036 105.80 –90 0.060 105.03 –80 0.097 104.26 –70 0.154 103.48 –60 0.236 102.70 –50 0.354 101.92 –40 0.519 101.13 –30 0.744 100.34 –20 1.046 99.54 –10 1.445 98.73 0 1.963 97.92 5 2.274 97.51 10 2.625 97.10 15 3.019 96.69 20 3.460 96.28 25 3.952 95.86 30 4.499 95.44 35 5.106 95.02 40 5.778 94.60 45 6.519 94.17 50 7.334 93.74 55 8.229 93.31 60 9.208 92.88 65 10.278 92.44 70 11.445 92.01 75 12.713 91.56 80 14.090 91.12 82.08b 14.696 90.94 85 15.580 90.67 90 17.192 90.22 95 18.931 89.77 100 20.804 89.31 105 22.819 88.85 110 24.980 88.39 115 27.297 87.92 120 29.776 87.45 125 32.425 86.98 130 35.251 86.50 135 38.261 86.01 140 41.464 85.52 145 44.868 85.03 150 48.479 84.53 160 56.360 83.52 170 65.173 82.49 180 74.986 81.43 190 85.868 80.34 200 97.892 79.23 210 111.13 78.08 220 125.66 76.89 230 141.56 75.66 240 158.91 74.38 250 177.80 73.04 260 198.31 71.64 270 220.53 70.16 280 244.58 68.60 290 270.54 66.92 300 298.53 65.11 310 328.69 63.12 320 361.16 60.91 330 396.11 58.37 340 433.76 55.33 350 474.41 51.32 360 518.66 43.97 362.63c 531.10 34.34 *Temperatures on ITS-90 scale

7431.6 3871.0 2111.6 1201.0 709.46 433.83 273.77 177.81 118.57 80.999 56.576 40.333 29.299 21.655 16.264 14.174 12.396 10.878 9.5779 8.4595 7.4943 6.6586 5.9327 5.3002 4.7474 4.2629 3.8371 3.4617 3.1301 2.8362 2.5753 2.4753 2.3429 2.1356 1.9503 1.7841 1.6349 1.5006 1.3795 1.2701 1.1710 1.0812 0.9996 0.9253 0.8577 0.7959 0.6876 0.5965 0.5195 0.4539 0.3979 0.3497 0.3080 0.2719 0.2404 0.2128 0.1885 0.1670 0.1479 0.1309 0.1155 0.1016 0.0889 0.0770 0.0658 0.0544 0.0403 0.0291

Refrigerants

Temp.,* Pressure, °F psia

Enthalpy, Btu/lb Liquid

Vapor

–22.241 71.783 –20.033 72.974 –17.826 74.187 –15.619 75.421 –13.410 76.676 –11.195 77.950 –8.975 79.244 –6.746 80.556 –4.509 81.885 –2.260 83.231 0.000 84.592 2.272 85.967 4.558 87.355 6.857 88.754 9.170 90.163 10.332 90.871 11.498 91.582 12.667 92.294 13.840 93.008 15.017 93.723 16.198 94.440 17.382 95.158 18.570 95.877 19.762 96.597 20.958 97.317 22.158 98.038 23.362 98.760 24.570 99.481 25.782 100.203 26.998 100.924 28.218 101.645 28.728 101.945 29.443 102.365 30.671 103.085 31.904 103.804 33.141 104.521 34.383 105.238 35.628 105.953 36.879 106.666 38.134 107.377 39.393 108.086 40.657 108.792 41.926 109.497 43.200 110.198 44.479 110.896 45.763 111.591 48.347 112.970 50.953 114.333 53.583 115.678 56.237 117.001 58.918 118.300 61.627 119.572 64.367 120.813 67.141 122.019 69.952 123.184 72.805 124.303 75.704 125.367 78.655 126.368 81.666 127.294 84.749 128.128 87.916 128.851 91.188 129.431 94.594 129.822 98.186 129.950 102.059 129.670 106.459 128.628 112.667 125.064 118.800 118.800 b Normal boiling point

Entropy, Btu/lb·°F

cp /cv Vapor

Liquid

Vapor

–0.06050 –0.05370 –0.04710 –0.04070 –0.03447 –0.02840 –0.02247 –0.01668 –0.01101 –0.00545 0.00000 0.00535 0.01061 0.01578 0.02086 0.02337 0.02587 0.02834 0.03080 0.03324 0.03566 0.03806 0.04045 0.04282 0.04518 0.04752 0.04984 0.05215 0.05444 0.05673 0.05899 0.05993 0.06124 0.06348 0.06571 0.06792 0.07012 0.07231 0.07449 0.07665 0.07881 0.08095 0.08308 0.08520 0.08732 0.08942 0.09359 0.09773 0.10184 0.10592 0.10997 0.11400 0.11801 0.12201 0.12599 0.12997 0.13396 0.13795 0.14196 0.14600 0.15010 0.15426 0.15853 0.16297 0.16769 0.17298 0.18039 0.18779

0.23363 1.1237 0.22843 1.1212 0.22379 1.1187 0.21966 1.1165 0.21600 1.1144 0.21275 1.1124 0.20989 1.1106 0.20737 1.1090 0.20516 1.1075 0.20323 1.1061 0.20157 1.1050 0.20014 1.1040 0.19892 1.1032 0.19790 1.1026 0.19706 1.1022 0.19670 1.1021 0.19638 1.1020 0.19609 1.1020 0.19585 1.1020 0.19563 1.1021 0.19544 1.1023 0.19529 1.1025 0.19517 1.1028 0.19507 1.1031 0.19500 1.1035 0.19495 1.1040 0.19493 1.1046 0.19493 1.1052 0.19495 1.1059 0.19499 1.1067 0.19505 1.1075 0.19508 1.1079 0.19513 1.1085 0.19522 1.1095 0.19534 1.1106 0.19546 1.1119 0.19560 1.1132 0.19576 1.1146 0.19593 1.1162 0.19611 1.1178 0.19630 1.1196 0.19650 1.1215 0.19671 1.1236 0.19693 1.1258 0.19716 1.1281 0.19739 1.1306 0.19788 1.1362 0.19839 1.1426 0.19892 1.1499 0.19945 1.1583 0.19999 1.1681 0.20053 1.1793 0.20106 1.1925 0.20158 1.2079 0.20207 1.2262 0.20254 1.2482 0.20296 1.2749 0.20334 1.3079 0.20365 1.3496 0.20387 1.4035 0.20398 1.4755 0.20395 1.5762 0.20372 1.7258 0.20320 1.9693 0.20222 2.4318 0.20036 3.6383 0.19551 14.6330 0.18779  c Critical point

116

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Refrigerants

Figure 9.3

Pressure-Enthalpy Diagram for Refrigerant 134a [2013F, Ch 30, Fig 8]

117

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Refrigerants

Table 9.5 R-134a (1,1,1,2-Tetrafluoroethane) Properties of Saturated Liquid and Saturated Vapor [2013F, Ch 30, Tbl R-134a]

Density, Temp.,* Pressure, lb/ft3 °F psia Liquid a 0.057 99.33 –153.94 –150 0.072 98.97 –140 0.129 98.05 –130 0.221 97.13 –120 0.365 96.20 –110 0.583 95.27 –100 0.903 94.33 –90 1.359 93.38 –80 1.993 92.42 –75 2.392 91.94 –70 2.854 91.46 –65 3.389 90.97 –60 4.002 90.49 –55 4.703 90.00 –50 5.501 89.50 –45 6.406 89.00 –40 7.427 88.50 –35 8.576 88.00 –30 9.862 87.49 –25 11.299 86.98 –20 12.898 86.47 –15 14.671 85.95 –14.93b 14.696 85.94 –10 16.632 85.43 –5 18.794 84.90 0 21.171 84.37 5 23.777 83.83 10 26.628 83.29 15 29.739 82.74 20 33.124 82.19 25 36.800 81.63 30 40.784 81.06 35 45.092 80.49 40 49.741 79.90 45 54.749 79.32 50 60.134 78.72 55 65.913 78.11 60 72.105 77.50 65 78.729 76.87 70 85.805 76.24 75 93.351 75.59 80 101.39 74.94 85 109.93 74.27 90 119.01 73.58 95 128.65 72.88 100 138.85 72.17 105 149.65 71.44 110 161.07 70.69 115 173.14 69.93 120 185.86 69.14 125 199.28 68.32 130 213.41 67.49 135 228.28 66.62 140 243.92 65.73 145 260.36 64.80 150 277.61 63.83 155 295.73 62.82 160 314.73 61.76 165 334.65 60.65 170 355.53 59.47 175 377.41 58.21 180 400.34 56.86 185 424.36 55.38 190 449.52 53.76 195 475.91 51.91 200 503.59 49.76 205 532.68 47.08 210 563.35 43.20 c 213.91 588.75 31.96 *Temperatures on ITS-90 scale

Volume, ft3/lb Vapor 568.59 452.12 260.63 156.50 97.481 62.763 41.637 28.381 19.825 16.711 14.161 12.060 10.321 8.8733 7.6621 6.6438 5.7839 5.0544 4.4330 3.9014 3.4449 3.0514 3.0465 2.7109 2.4154 2.1579 1.9330 1.7357 1.5623 1.4094 1.2742 1.1543 1.0478 0.9528 0.8680 0.7920 0.7238 0.6625 0.6072 0.5572 0.5120 0.4710 0.4338 0.3999 0.3690 0.3407 0.3148 0.2911 0.2693 0.2493 0.2308 0.2137 0.1980 0.1833 0.1697 0.1571 0.1453 0.1343 0.1239 0.1142 0.1051 0.0964 0.0881 0.0801 0.0724 0.0647 0.0567 0.0477 0.0313

Enthalpy, Btu/lb Liquid –32.992 –31.878 –29.046 –26.208 –23.360 –20.500 –17.626 –14.736 –11.829 –10.368 –8.903 –7.432 –5.957 –4.476 –2.989 –1.498 0.000 1.503 3.013 4.529 6.051 7.580 7.600 9.115 10.657 12.207 13.764 15.328 16.901 18.481 20.070 21.667 23.274 24.890 26.515 28.150 29.796 31.452 33.120 34.799 36.491 38.195 39.913 41.645 43.392 45.155 46.934 48.731 50.546 52.382 54.239 56.119 58.023 59.954 61.915 63.908 65.936 68.005 70.118 72.283 74.509 76.807 79.193 81.692 84.343 87.214 90.454 94.530 103.894 a

Vapor 80.362 80.907 82.304 83.725 85.168 86.629 88.107 89.599 91.103 91.858 92.614 93.372 94.131 94.890 95.650 96.409 97.167 97.924 98.679 99.433 100.184 100.932 100.942 101.677 102.419 103.156 103.889 104.617 105.339 106.056 106.767 107.471 108.167 108.856 109.537 110.209 110.871 111.524 112.165 112.796 113.414 114.019 114.610 115.186 115.746 116.289 116.813 117.317 117.799 118.258 118.690 119.095 119.468 119.807 120.108 120.366 120.576 120.731 120.823 120.842 120.773 120.598 120.294 119.822 119.123 118.097 116.526 113.746 103.894

Triple point

Entropy, Btu/lb·°F Liquid –0.09154 –0.08791 –0.07891 –0.07017 –0.06166 –0.05337 –0.04527 –0.03734 –0.02959 –0.02577 –0.02198 –0.01824 –0.01452 –0.01085 –0.00720 –0.00358 0.00000 0.00356 0.00708 0.01058 0.01406 0.01751 0.01755 0.02093 0.02433 0.02771 0.03107 0.03440 0.03772 0.04101 0.04429 0.04755 0.05079 0.05402 0.05724 0.06044 0.06362 0.06680 0.06996 0.07311 0.07626 0.07939 0.08252 0.08565 0.08877 0.09188 0.09500 0.09811 0.10123 0.10435 0.10748 0.11062 0.11376 0.11692 0.12010 0.12330 0.12653 0.12979 0.13309 0.13644 0.13985 0.14334 0.14693 0.15066 0.15459 0.15880 0.16353 0.16945 0.18320 b

Vapor 0.27923 0.27629 0.26941 0.26329 0.25784 0.25300 0.24871 0.24490 0.24152 0.23998 0.23854 0.23718 0.23590 0.23470 0.23358 0.23252 0.23153 0.23060 0.22973 0.22892 0.22816 0.22744 0.22743 0.22678 0.22615 0.22557 0.22502 0.22451 0.22403 0.22359 0.22317 0.22278 0.22241 0.22207 0.22174 0.22144 0.22115 0.22088 0.22062 0.22037 0.22013 0.21989 0.21966 0.21944 0.21921 0.21898 0.21875 0.21851 0.21826 0.21800 0.21772 0.21742 0.21709 0.21673 0.21634 0.21591 0.21542 0.21488 0.21426 0.21356 0.21274 0.21180 0.21069 0.20935 0.20771 0.20562 0.20275 0.19814 0.18320

Normal boiling point

Specific Heat cp , Btu/lb·°F Liquid 0.2829 0.2830 0.2834 0.2842 0.2853 0.2866 0.2881 0.2898 0.2916 0.2925 0.2935 0.2945 0.2955 0.2965 0.2976 0.2987 0.2999 0.3010 0.3022 0.3035 0.3047 0.3060 0.3061 0.3074 0.3088 0.3102 0.3117 0.3132 0.3147 0.3164 0.3181 0.3198 0.3216 0.3235 0.3255 0.3275 0.3297 0.3319 0.3343 0.3368 0.3394 0.3422 0.3451 0.3482 0.3515 0.3551 0.3589 0.3630 0.3675 0.3723 0.3775 0.3833 0.3897 0.3968 0.4048 0.4138 0.4242 0.4362 0.4504 0.4675 0.4887 0.5156 0.5512 0.6012 0.6768 0.8062 1.0830 2.1130 

Vapor 0.1399 0.1411 0.1443 0.1475 0.1508 0.1540 0.1573 0.1607 0.1641 0.1658 0.1676 0.1694 0.1713 0.1731 0.1751 0.1770 0.1790 0.1811 0.1832 0.1853 0.1875 0.1898 0.1898 0.1921 0.1945 0.1969 0.1995 0.2021 0.2047 0.2075 0.2103 0.2132 0.2163 0.2194 0.2226 0.2260 0.2294 0.2331 0.2368 0.2408 0.2449 0.2492 0.2537 0.2585 0.2636 0.2690 0.2747 0.2809 0.2875 0.2948 0.3026 0.3112 0.3208 0.3315 0.3435 0.3571 0.3729 0.3914 0.4133 0.4400 0.4733 0.5159 0.5729 0.6532 0.7751 0.9835 1.4250 3.0080  c

cp /cv Vapor 1.1637 1.1623 1.1589 1.1559 1.1532 1.1509 1.1490 1.1475 1.1465 1.1462 1.1460 1.1459 1.1460 1.1462 1.1466 1.1471 1.1478 1.1486 1.1496 1.1508 1.1521 1.1537 1.1537 1.1554 1.1573 1.1595 1.1619 1.1645 1.1674 1.1705 1.1740 1.1777 1.1818 1.1862 1.1910 1.1961 1.2018 1.2079 1.2145 1.2217 1.2296 1.2382 1.2475 1.2578 1.2690 1.2813 1.2950 1.3101 1.3268 1.3456 1.3666 1.3903 1.4173 1.4481 1.4837 1.5250 1.5738 1.6318 1.7022 1.7889 1.8984 2.0405 2.2321 2.5041 2.9192 3.6309 5.1360 10.5120 

Critical point

118

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Table 9.6

Superheated Vapor Thermodynamic Properties of R-134a

40 60

Pressure = 15 psia Sat. temp. = 14.25°F V h s 3.118 103.35 0.2324 3.268 107.07 0.2403 3.417 110.88 0.2481 3.565 114.79 0.2558 3.712 118.79 0.2633 3.858 122.87 0.2708 4.004 127.05 0.2781 4.149 131.31 0.2853 Pressure = 45 psia Sat. temp. = 34.94°F V h s 1.077 109.20 0.2243 1.132 113.24 0.2323

0.8269

80 100 120 140

1.187 1.240 1.293 1.345

0.8699 0.9120 0.9533 0.9940

Temp, °F 0 20 40 60 80 100 120 140 Temp, °F

Temp, °F 125 150 175 200 225 250

150 175 200 225 250 275 300

s

1.584 1.663 1.741 1.818 1.895 1.971 2.046

106.18 0.2255 110.06 0.2335 114.03 0.2413 118.08 0.2489 122.22 0.2564 126.44 0.2638 130.75 0.2711 Pressure = 60 psia Sat. temp. = 49.94°F V h s 112.41

0.2255

116.60 0.2334 120.86 0.2412 125.18 0.2488 129.58 0.2562 Pressure = 200 psia Sat. temp. = 125.19°F V h s

0.2596 0.2807 0.3003 0.3189 0.3366

125.69 0.2289 132.07 0.2391 138.42 0.2489 144.80 0.2584 151.23 0.2676 Pressure = 300 psia Sat. temp. = 156.07°F V h s

0.1646 0.1817 0.1969 0.2110 0.2242 0.2367

127.20 134.35 141.29 148.15 154.99 161.84

Refrigerants

Temp, °F

117.36 0.2400 121.55 0.2477 125.82 0.2552 130.17 0.2625 Pressure = 150 psia Sat. temp. = 105.14°F V h s 0.3433 122.06 0.2274 0.3692 128.08 0.2375 0.3937 134.13 0.2472 0.4171 140.23 0.2566 0.4397 146.41 0.2658 0.4616 152.66 0.2748 Pressure = 250 psia Sat. temp. = 141.79°F V h s 0.1920 122.93 0.2210 0.2118 129.79 0.2320 0.2295 136.47 0.2423 0.2460 143.10 0.2522 0.2614 149.73 0.2617 0.2761 156.37 0.2709 0.2902 163.07 0.2798

Pressure = 30 psia Sat. temp. = 15.39°F V h

0.2252 0.2362 0.2466 0.2564 0.2659 0.2750

V = vapor volume, ft3/lb h = enthalpy, Btu/lb s = entropy, Btu/lb·°F

119

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Refrigerants


Figure 9.4 Pressure-Enthalpy Diagram for Refrigerant 717 (Ammonia) [2013F, Ch 30, Fig 18]

120

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Table 9.7

R-717 (Ammonia) Properties of Saturated Liquid and Saturated Vapor [2013F, Ch 30, Tbl R-717]

Density, Volume, Temp.,* Pressure, lb/ft3 ft3/lb °F psia Liquid Vapor 249.92 182.19 124.12 86.546 61.647 44.774 33.105 24.881 18.983 18.007 16.668 14.684 12.976 11.502 10.226 9.1159 8.1483 7.3020 6.5597 5.9067 5.3307 4.8213 4.3695 3.9680 3.6102 3.2906 3.0045 2.7479 2.5172 2.3094 2.1217 1.9521 1.7983 1.6588 1.5319 1.4163 1.3108 1.2144 1.1262 1.0452 0.9710 0.9026 0.8397 0.7817 0.7280 0.6785 0.6325 0.5899 0.5504 0.5136 0.4793 0.4473 0.4174 0.3895 0.3633 0.3387 0.3156 0.2938 0.2733 0.2538 0.2354 0.2178 0.2010 0.1849 0.1693 0.1540 0.1233 0.0712

–69.830 568.765 –61.994 572.260 –51.854 576.688 –41.637 581.035 –31.341 585.288 –20.969 589.439 –10.521 593.476 0.000 597.387 10.592 601.162 12.732 601.904 15.914 602.995 21.253 604.789 26.609 606.544 31.982 608.257 37.372 609.928 42.779 611.554 48.203 613.135 53.644 614.669 59.103 616.154 64.579 617.590 70.072 618.974 75.585 620.305 81.116 621.582 86.666 622.803 92.237 623.967 97.828 625.072 103.441 626.115 109.076 627.097 114.734 628.013 120.417 628.864 126.126 629.647 131.861 630.359 137.624 630.999 143.417 631.564 149.241 632.052 155.098 632.460 160.990 632.785 166.919 633.025 172.887 633.175 178.896 633.232 184.949 633.193 191.049 633.053 197.199 632.807 203.403 632.451 209.663 631.978 215.984 631.383 222.370 630.659 228.827 629.798 235.359 628.791 241.973 627.630 248.675 626.302 255.472 624.797 262.374 623.100 269.390 621.195 276.530 619.064 283.809 616.686 291.240 614.035 298.842 611.081 306.637 607.788 314.651 604.112 322.918 599.996 331.483 595.371 340.404 590.142 349.766 584.183 359.695 577.309 370.391 569.240 395.943 547.139 473.253 473.253 a Triple point

Entropy, Btu/lb·°F Liquid Vapor

Specific Heat cp , Btu/lb·°F Liquid Vapor

–0.18124 1.63351 1.0044 –0.15922 1.60421 1.0100 –0.13142 1.56886 1.0176 –0.10416 1.53587 1.0254 –0.07741 1.50503 1.0331 –0.05114 1.47614 1.0406 –0.02534 1.44900 1.0478 0.00000 1.42347 1.0549 0.02491 1.39938 1.0617 0.02987 1.39470 1.0631 0.03720 1.38784 1.0651 0.04939 1.37660 1.0684 0.06148 1.36567 1.0716 0.07347 1.35502 1.0749 0.08536 1.34463 1.0782 0.09715 1.33450 1.0814 0.10885 1.32462 1.0847 0.12045 1.31496 1.0880 0.13197 1.30552 1.0914 0.14340 1.29629 1.0948 0.15474 1.28726 1.0983 0.16599 1.27842 1.1019 0.17717 1.26975 1.1056 0.18827 1.26125 1.1094 0.19929 1.25291 1.1134 0.21024 1.24472 1.1175 0.22111 1.23667 1.1218 0.23192 1.22875 1.126 0.24266 1.22095 1.131 0.25334 1.21327 1.136 0.26396 1.20570 1.141 0.27452 1.19823 1.147 0.28503 1.19085 1.153 0.29549 1.18356 1.159 0.30590 1.17634 1.166 0.31626 1.16920 1.173 0.32659 1.16211 1.180 0.33688 1.15508 1.188 0.34713 1.14809 1.197 0.35736 1.14115 1.206 0.36757 1.13423 1.216 0.37775 1.12733 1.227 0.38792 1.12044 1.239 0.39808 1.11356 1.251 0.40824 1.10666 1.265 0.41840 1.09975 1.280 0.42857 1.09281 1.296 0.43875 1.08582 1.313 0.44896 1.07878 1.333 0.45919 1.07167 1.354 0.46947 1.06447 1.377 0.47980 1.05717 1.403 0.49019 1.04974 1.432 0.50066 1.04217 1.465 0.51121 1.03443 1.502 0.52188 1.02649 1.543 0.53267 1.01831 1.591 0.54360 1.00986 1.646 0.55472 1.00109 1.711 0.56605 0.99193 1.788 0.57763 0.98232 1.882 0.58953 0.97216 1.999 0.60182 0.96133 2.148 0.61462 0.94966 2.346 0.62809 0.93690 2.624 0.64249 0.92269 3.047 0.67662 0.88671 5.273 0.78093 0.78093  b Normal boiling point

cp /cv Vapor

0.4930 1.3252 0.4959 1.3262 0.5003 1.3278 0.5056 1.3296 0.5118 1.3319 0.5190 1.3346 0.5271 1.3379 0.5364 1.3419 0.5467 1.3465 0.5490 1.3475 0.5524 1.3491 0.5583 1.3520 0.5646 1.3550 0.5711 1.3584 0.5781 1.3619 0.5853 1.3657 0.5929 1.3698 0.6009 1.3742 0.6092 1.3789 0.6179 1.3840 0.6271 1.3894 0.6366 1.3951 0.6465 1.4012 0.6569 1.4078 0.6678 1.4147 0.6791 1.4222 0.6909 1.4301 0.703 1.438 0.716 1.447 0.730 1.457 0.744 1.467 0.758 1.478 0.774 1.490 0.790 1.502 0.807 1.515 0.824 1.529 0.843 1.544 0.862 1.561 0.883 1.578 0.905 1.597 0.928 1.617 0.952 1.638 0.978 1.662 1.006 1.687 1.035 1.715 1.067 1.745 1.101 1.778 1.138 1.813 1.178 1.853 1.222 1.896 1.270 1.944 1.322 1.998 1.381 2.058 1.446 2.126 1.519 2.203 1.602 2.290 1.697 2.392 1.806 2.509 1.935 2.648 2.088 2.814 2.272 3.015 2.501 3.265 2.790 3.582 3.171 4.000 3.693 4.575 4.460 5.420 8.106 9.439   c Critical point

Refrigerants

–107.78a 0.883 45.75 –100 1.237 45.47 –90 1.864 45.09 –80 2.739 44.71 –70 3.937 44.31 –60 5.544 43.91 –50 7.659 43.50 –40 10.398 43.08 –30 13.890 42.66 –27.99b 14.696 42.57 –25 15.962 42.45 –20 18.279 42.23 –15 20.858 42.01 –10 23.723 41.79 –5 26.895 41.57 0 30.397 41.34 5 34.253 41.12 10 38.487 40.89 15 43.126 40.66 20 48.194 40.43 25 53.720 40.20 30 59.730 39.96 35 66.255 39.72 40 73.322 39.48 45 80.962 39.24 50 89.205 38.99 55 98.083 38.75 60 107.63 38.50 65 117.87 38.25 70 128.85 37.99 75 140.59 37.73 80 153.13 37.47 85 166.51 37.21 90 180.76 36.94 95 195.91 36.67 100 212.01 36.40 105 229.09 36.12 110 247.19 35.83 115 266.34 35.55 120 286.60 35.26 125 307.98 34.96 130 330.54 34.66 135 354.32 34.35 140 379.36 34.04 145 405.70 33.72 150 433.38 33.39 155 462.45 33.06 160 492.95 32.72 165 524.94 32.37 170 558.45 32.01 175 593.53 31.64 180 630.24 31.26 185 668.63 30.87 190 708.74 30.47 195 750.64 30.05 200 794.38 29.62 205 840.03 29.17 210 887.64 28.70 215 937.28 28.21 220 989.03 27.69 225 1042.96 27.15 230 1099.14 26.57 235 1157.69 25.95 240 1218.68 25.28 245 1282.24 24.55 250 1348.49 23.72 260 1489.71 21.60 270.05c 1643.71 14.05 *Temperatures on ITS-90 scale

Enthalpy, Btu/lb Liquid Vapor

121

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Refrigerants


Figure 9.5 Pressure-Enthalpy Diagram for Refrigerant 404A [2013F, Ch 30, Fig 14]

122

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Table 9.8 R-404A [R-125/143a/134a (44/52/4)] Properties of Liquid on Bubble Line and Vapor on Dew Line [2013F, Ch 30, Tbl R-404A] Temperature,* °F Bubble –129.56 –120.05 –112.90 –107.10 –102.18 –94.08 –87.49 –81.89 –77.00 –72.64 –65.08 –58.65 –53.01 –51.20 –47.98 –43.42 –39.24 –35.37 –31.77 –28.39 –25.21 –22.20 –19.34 –16.62 –14.01 –11.52 –9.12 –6.81 –4.59 –2.44 –0.36 1.65 6.43 10.89 15.07 19.02 22.76 26.32 29.71 32.96 36.07 39.07 44.73 50.02 54.99 59.68 64.13 68.36 72.40 76.26 79.97 83.53 90.27 96.57 102.48 108.06 113.34 118.36 123.14 127.71 132.09 136.28 146.07 154.97 162.50

Density, lb/ft3 Liquid 89.61 88.64 87.92 87.33 86.83 86.01 85.33 84.76 84.25 83.80 83.01 82.34 81.74 81.55 81.20 80.71 80.26 79.83 79.44 79.06 78.71 78.37 78.05 77.74 77.44 77.15 76.87 76.60 76.34 76.09 75.84 75.60 75.03 74.48 73.97 73.47 72.99 72.54 72.09 71.67 71.25 70.84 70.06 69.32 68.60 67.90 67.23 66.57 65.93 65.30 64.68 64.07 62.87 61.70 60.53 59.37 58.20 57.03 55.83 54.61 53.35 52.03 48.36 43.51 35.84

Dew –127.50 –118.11 –111.03 –105.29 –100.42 –92.40 –85.87 –80.32 –75.46 –71.14 –63.64 –57.25 –51.65 –49.85 –46.65 –42.11 –37.96 –34.11 –30.53 –27.17 –24.01 –21.02 –18.17 –15.46 –12.87 –10.39 –8.01 –5.71 –3.50 –1.36 0.71 2.71 7.47 11.90 16.07 20.00 23.72 27.27 30.64 33.88 36.98 39.96 45.60 50.86 55.81 60.48 64.91 69.13 73.15 76.99 80.68 84.23 90.94 97.21 103.09 108.64 113.90 118.89 123.65 128.19 132.54 136.71 146.42 155.22 162.50

*Temperatures on ITS-90 scale

b

Volume, ft3/lb Vapor 36.2311 24.7754 18.9245 15.3578 12.9493 9.8941 8.0300 6.7705 5.8607 5.1716 4.1954 3.5353 3.0582 2.9217 2.6968 2.4132 2.1845 1.9960 1.8379 1.7033 1.5873 1.4863 1.3974 1.3187 1.2484 1.1852 1.1281 1.0763 1.0290 0.9857 0.9459 0.9091 0.8285 0.7609 0.7033 0.6537 0.6104 0.5724 0.5387 0.5085 0.4815 0.4570 0.4145 0.3789 0.3485 0.3222 0.2994 0.2793 0.2614 0.2454 0.2311 0.2181 0.1955 0.1764 0.1601 0.1460 0.1336 0.1226 0.1127 0.1038 0.0956 0.0881 0.0713 0.0556 0.0279

Enthalpy, Btu/lb Liquid –26.33 –23.56 –21.49 –19.81 –18.38 –16.02 –14.10 –12.46 –11.02 –9.74 –7.51 –5.60 –3.91 –3.37 –2.41 –1.03 0.23 1.40 2.50 3.53 4.51 5.44 6.32 7.16 7.97 8.75 9.50 10.22 10.92 11.60 12.25 12.89 14.41 15.84 17.19 18.47 19.69 20.86 21.98 23.05 24.09 25.10 27.01 28.82 30.53 32.16 33.73 35.23 36.68 38.08 39.44 40.76 43.29 45.70 48.02 50.25 52.42 54.54 56.61 58.65 60.67 62.68 67.80 73.49 80.85

Vapor 71.76 73.11 74.14 74.98 75.69 76.86 77.82 78.64 79.35 79.98 81.07 82 82.81 83.07 83.53 84.18 84.78 85.32 85.83 86.30 86.75 87.16 87.56 87.93 88.29 88.62 88.95 89.26 89.56 89.84 90.12 90.38 91.01 91.58 92.11 92.61 93.07 93.50 93.91 94.30 94.66 95.00 95.64 96.21 96.73 97.20 97.62 98.01 98.37 98.69 98.98 99.25 99.70 100.05 100.32 100.51 100.61 100.64 100.58 100.43 100.20 99.85 98.42 95.51 80.85

Bubble and dew points at one standard atmosphere

Entropy, Btu/lb·°F Liquid –0.07039 –0.06215 –0.05611 –0.05129 –0.04727 –0.04076 –0.03555 –0.03119 –0.02742 –0.02409 –0.01839 –0.01360 –0.00944 –0.00812 –0.00577 –0.00246 0.00055 0.00332 0.00588 0.00827 0.01051 0.01263 0.01463 0.01653 0.01834 0.02007 0.02172 0.02331 0.02484 0.02632 0.02774 0.02911 0.03237 0.03539 0.03822 0.04088 0.04339 0.04578 0.04804 0.05021 0.05229 0.05428 0.05804 0.06155 0.06485 0.06795 0.07090 0.07371 0.07639 0.07896 0.08143 0.08381 0.08833 0.09259 0.09663 0.10047 0.10417 0.10773 0.11118 0.11456 0.11787 0.12114 0.12934 0.13833 0.14987 c

Vapor 0.22616 0.22201 0.21920 0.21710 0.21544 0.21292 0.21106 0.20960 0.20841 0.20741 0.20581 0.20457 0.20357 0.20326 0.20273 0.20203 0.20141 0.20088 0.20041 0.19998 0.19960 0.19925 0.19894 0.19864 0.19838 0.19813 0.19790 0.19768 0.19748 0.19729 0.19711 0.19694 0.19655 0.19621 0.19590 0.19562 0.19537 0.19514 0.19492 0.19471 0.19452 0.19434 0.19400 0.19368 0.19338 0.19309 0.19281 0.19253 0.19226 0.19198 0.19170 0.19143 0.19085 0.19026 0.18962 0.18895 0.18823 0.18745 0.18660 0.18566 0.18464 0.18349 0.17987 0.17416 0.14987

Refrigerants

Pressure, psia 1 1.5 2 2.5 3 4 5 6 7 8 10 12 14 14.7b 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 55 60 65 70 75 80 85 90 95 100 110 120 130 140 150 160 170 180 190 200 220 240 260 280 300 320 340 360 380 400 450 500 548.24c

Critical point 123

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Refrigerants


Figure 9.6 Pressure-Enthalpy Diagram for Refrigerant 407C [2013F, Ch 30, Fig 15]

124

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Table 9.9 R-407C [R-32/125/134a (23/25/52)] Properties of Liquid on Bubble Line and Vapor on Dew Line [2013F, Ch 30, Tbl R-407C] Temp.,* °F Pressure, psia Bubble Dew

94.24 93.28 92.55 91.97 91.47 90.64 89.97 89.40 88.89 88.44 87.66 86.98 86.39 86.19 85.85 85.36 84.91 84.50 84.10 83.73 83.38 83.05 82.73 82.43 82.14 81.85 81.58 81.32 81.06 80.82 80.58 80.34 79.78 79.25 78.75 78.27 77.82 77.38 76.95 76.54 76.15 75.76 75.02 74.32 73.64 72.99 72.37 71.76 71.17 70.59 70.02 69.47 68.40 67.35 66.33 65.33 64.34 63.37 62.39 61.42 60.44 59.46 56.92 54.21 51.15 47.39 41.60 31.59

Entropy, Btu/lb·°F Liquid Vapor

43.0887 –26.34 93.96 –0.07002 0.28254 29.4430 –23.40 95.34 –0.06135 0.27716 22.4776 –21.18 96.37 –0.05499 0.27346 18.2333 –19.39 97.21 –0.04994 0.27066 15.3685 –17.87 97.92 –0.04572 0.26841 11.7361 –15.37 99.09 –0.03889 0.26495 9.5211 –13.34 100.03 –0.03345 0.26234 8.0252 –11.60 100.83 –0.02889 0.26025 6.9450 –10.09 101.52 –0.02496 0.25852 6.1272 –8.74 102.13 –0.02149 0.25705 4.9690 –6.39 103.19 –0.01556 0.25464 4.1864 –4.38 104.08 –0.01059 0.25272 3.6210 –2.62 104.85 –0.00629 0.25114 3.4593 –2.06 105.10 –0.00492 0.25065 3.1928 –1.05 105.54 –0.00249 0.24979 2.8570 0.39 106.15 0.00092 0.24863 2.5862 1.70 106.71 0.00402 0.24760 2.3632 2.92 107.22 0.00687 0.24668 2.1761 4.06 107.70 0.00950 0.24586 2.0169 5.13 108.14 0.01196 0.24510 1.8798 6.15 108.55 0.01426 0.24442 1.7603 7.10 108.93 0.01643 0.24378 1.6553 8.02 109.30 0.01848 0.24319 1.5622 8.89 109.64 0.02042 0.24265 1.4791 9.72 109.97 0.02227 0.24213 1.4045 10.53 110.28 0.02404 0.24165 1.3371 11.30 110.58 0.02573 0.24120 1.2759 12.04 110.86 0.02735 0.24077 1.2201 12.76 111.13 0.02891 0.24036 1.1690 13.46 111.39 0.03041 0.23998 1.1220 14.13 111.64 0.03186 0.23961 1.0786 14.79 111.88 0.03326 0.23926 0.9835 16.34 112.44 0.03656 0.23844 0.9037 17.81 112.96 0.03963 0.23771 0.8359 19.19 113.44 0.04250 0.23703 0.7774 20.49 113.88 0.04519 0.23641 0.7264 21.74 114.29 0.04773 0.23584 0.6816 22.92 114.67 0.05014 0.23530 0.6419 24.06 115.03 0.05243 0.23480 0.6064 25.16 115.37 0.05462 0.23432 0.5746 26.21 115.68 0.05671 0.23387 0.5458 27.23 115.98 0.05871 0.23344 0.4959 29.16 116.53 0.06250 0.23265 0.4540 30.99 117.03 0.06602 0.23191 0.4183 32.72 117.47 0.06932 0.23122 0.3875 34.36 117.88 0.07244 0.23058 0.3607 35.94 118.24 0.07538 0.22997 0.3372 37.45 118.57 0.07818 0.22938 0.3163 38.90 118.87 0.08086 0.22882 0.2976 40.30 119.15 0.08341 0.22828 0.2808 41.66 119.39 0.08587 0.22776 0.2656 42.97 119.61 0.08823 0.22725 0.2393 45.49 119.99 0.09271 0.22625 0.2171 47.88 120.29 0.09691 0.22529 0.1982 50.17 120.52 0.10088 0.22434 0.1819 52.36 120.68 0.10464 0.22340 0.1676 54.48 120.78 0.10824 0.22246 0.1550 56.53 120.82 0.11168 0.22152 0.1438 58.53 120.80 0.11500 0.22056 0.1337 60.47 120.73 0.11821 0.21958 0.1246 62.38 120.61 0.12132 0.21857 0.1163 64.25 120.42 0.12435 0.21753 0.0984 68.84 119.71 0.13167 0.21473 0.0835 73.37 118.56 0.13879 0.21152 0.0706 78.00 116.83 0.14595 0.20765 0.0586 83.04 114.18 0.15363 0.20253 0.0457 89.56 109.19 0.16351 0.19401 0.0317 99.99 99.99 0.17797 0.17797 b Bubble and dew points at one standard atmosphere

Specific Heat cp , Btu/lb·°F cp /cv Liquid Vapor Vapor 0.3065 0.1568 1.183 0.3063 0.1600 1.182 0.3063 0.1624 1.181 0.3065 0.1644 1.181 0.3068 0.1662 1.181 0.3074 0.1693 1.181 0.3081 0.1719 1.182 0.3087 0.1742 1.182 0.3094 0.1762 1.183 0.3100 0.1781 1.184 0.3112 0.1814 1.186 0.3123 0.1844 1.188 0.3133 0.1871 1.189 0.3137 0.1880 1.190 0.3143 0.1896 1.191 0.3153 0.1919 1.193 0.3162 0.1941 1.195 0.3172 0.1961 1.197 0.3180 0.1981 1.199 0.3189 0.1999 1.201 0.3197 0.2017 1.203 0.3205 0.2034 1.205 0.3213 0.2051 1.207 0.3221 0.2067 1.209 0.3229 0.2083 1.211 0.3236 0.2098 1.213 0.3244 0.2113 1.215 0.3251 0.2127 1.217 0.3258 0.2141 1.219 0.3265 0.2155 1.221 0.3272 0.2169 1.223 0.3279 0.2182 1.225 0.3296 0.2214 1.230 0.3313 0.2246 1.235 0.3329 0.2276 1.240 0.3346 0.2305 1.245 0.3362 0.2333 1.250 0.3378 0.2361 1.255 0.3393 0.2389 1.260 0.3409 0.2416 1.266 0.3424 0.2442 1.271 0.3440 0.2468 1.276 0.3471 0.2520 1.287 0.3502 0.2570 1.298 0.3533 0.2621 1.310 0.3564 0.2671 1.321 0.3596 0.2721 1.334 0.3628 0.2772 1.346 0.3660 0.2824 1.359 0.3693 0.2876 1.373 0.3727 0.2929 1.387 0.3761 0.2983 1.401 0.3832 0.3095 1.432 0.3907 0.3213 1.466 0.3986 0.3338 1.502 0.4070 0.3473 1.542 0.4161 0.3618 1.586 0.4260 0.3777 1.635 0.4368 0.3951 1.689 0.4487 0.4143 1.750 0.4620 0.4358 1.819 0.4769 0.4600 1.897 0.5248 0.5373 2.151 0.5982 0.6546 2.541 0.7284 0.8572 3.217 1.0271 1.2973 4.683 2.4146 3.0022 10.265 — — — c Critical point

Refrigerants

1 –125.19 –111.30 1.5 –115.58 –101.85 2 –108.36 –94.75 2.5 –102.52 –88.99 3 –97.57 –84.12 4 –89.43 –76.11 5 –82.81 –69.61 6 –77.20 –64.09 7 –72.30 –59.27 8 –67.94 –54.97 10 –60.38 –47.55 12 –53.96 –41.23 14 –48.34 –35.71 14.7b –46.53 –33.93 16 –43.32 –30.78 18 –38.77 –26.31 20 –34.61 –22.23 22 –30.76 –18.45 24 –27.18 –14.93 26 –23.83 –11.64 28 –20.66 –8.54 30 –17.67 –5.60 32 –14.84 –2.82 34 –12.13 –0.17 36 –9.55 2.37 38 –7.07 4.79 40 –4.70 7.12 42 –2.41 9.37 44 –0.20 11.53 46 1.93 13.61 48 3.98 15.63 50 5.98 17.58 55 10.71 22.21 60 15.13 26.53 65 19.27 30.58 70 23.18 34.40 75 26.88 38.02 80 30.39 41.46 85 33.75 44.73 90 36.96 47.87 95 40.04 50.87 100 43.00 53.75 110 48.60 59.21 120 53.83 64.30 130 58.75 69.08 140 63.39 73.59 150 67.79 77.86 160 71.98 81.92 170 75.97 85.79 180 79.80 89.49 190 83.47 93.04 200 87.00 96.45 220 93.69 102.90 240 99.94 108.92 260 105.82 114.56 280 111.37 119.88 300 116.64 124.91 320 121.66 129.69 340 126.45 134.24 360 131.03 138.58 380 135.43 142.73 400 139.66 146.71 450 149.59 155.98 500 158.73 164.41 550 167.22 172.09 600 175.17 179.07 650 182.79 185.22 673.36c 186.94 186.94 *Temperatures on ITS-90 scale

Enthalpy, Density, Volume, Btu/lb ft3/lb lb/ft3 Liquid Vapor Liquid Vapor

125

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Refrigerants



126

further reprodu


Table 9.10

Temp.,* °F Bubble –135.16 –126.03 –119.18 –113.63 –108.94 –101.22 –94.94 –89.63 –84.98 –80.85 –73.70 –67.62 –62.31 –60.60 –57.56 –53.27 –49.34 –45.70 –42.32 –39.15 –36.17 –33.35 –30.68 –28.13 –25.69 –23.36 –21.12 –18.96 –16.89 –14.88 –12.94 –11.07 –6.62 –2.46 1.43 5.10 8.58 11.88 15.03 18.05 20.93 23.71 28.96 33.86 38.46 42.80 46.91 50.82 54.56 58.13 61.55 64.84 71.07 76.89 82.35 87.51 92.40 97.04 101.48 105.71 109.78 113.68 122.82 131.19 138.93 146.12 158.40

Dew –134.98 –125.87 –119.02 –113.48 –108.78 –101.07 –94.80 –89.48 –84.84 –80.71 –73.56 –67.48 –62.16 –60.46 –57.42 –53.13 –49.19 –45.56 –42.18 –39.01 –36.02 –33.20 –30.53 –27.98 –25.54 –23.20 –20.96 –18.81 –16.73 –14.73 –12.79 –10.91 –6.45 –2.30 1.60 5.27 8.75 12.06 15.21 18.22 21.11 23.89 29.14 34.05 38.65 42.99 47.11 51.02 54.76 58.33 61.76 65.05 71.28 77.10 82.57 87.73 92.61 97.26 101.69 105.93 109.99 113.89 123.01 131.38 139.09 146.25 158.40


Density, lb/ft3 Liquid 92.02 91.10 90.41 89.84 89.36 88.57 87.92 87.36 86.87 86.44 85.67 85.02 84.44 84.26 83.93 83.45 83.02 82.61 82.23 81.87 81.54 81.21 80.90 80.61 80.33 80.05 79.79 79.54 79.29 79.05 78.82 78.59 78.05 77.54 77.06 76.60 76.15 75.73 75.32 74.93 74.54 74.17 73.46 72.78 72.13 71.51 70.90 70.32 69.75 69.20 68.66 68.13 67.10 66.11 65.14 64.19 63.26 62.34 61.42 60.52 59.61 58.70 56.39 53.97 51.32 48.24 34.18 b

Enthalpy, Entropy, Specific Heat cp , Volume, Btu/lb·°F Btu/lb Btu/lb·°F ft3/lb Vapor Liquid Vapor Vapor Liquid Vapor Liquid 47.6458 –30.90 100.62 –0.08330 0.32188 0.3215 0.1568 32.5774 –27.97 101.90 –0.07439 0.31477 0.3212 0.1600 24.8810 –25.76 102.86 –0.06786 0.30981 0.3213 0.1626 20.1891 –23.98 103.63 –0.06267 0.30602 0.3214 0.1648 17.0211 –22.47 104.27 –0.05834 0.30296 0.3216 0.1668 13.0027 –19.98 105.33 –0.05133 0.29820 0.3221 0.1703 10.5514 –17.96 106.18 –0.04574 0.29455 0.3226 0.1733 8.8953 –16.24 106.89 –0.04107 0.29162 0.3231 0.1760 7.6992 –14.74 107.50 –0.03704 0.28916 0.3236 0.1785 6.7935 –13.40 108.05 –0.03349 0.28705 0.3241 0.1807 5.5105 –11.08 108.97 –0.02743 0.28356 0.3251 0.1848 4.6434 –9.10 109.75 –0.02235 0.28075 0.3261 0.1884 4.0168 –7.36 110.42 –0.01795 0.27840 0.3270 0.1917 3.8375 –6.80 110.63 –0.01655 0.27766 0.3274 0.1928 3.5423 –5.80 111.01 –0.01407 0.27638 0.3279 0.1947 3.1699 –4.39 111.54 –0.01059 0.27461 0.3288 0.1975 2.8698 –3.09 112.01 –0.00743 0.27305 0.3297 0.2002 2.6225 –1.89 112.45 –0.00452 0.27164 0.3305 0.2027 2.4151 –0.77 112.85 –0.00184 0.27036 0.3313 0.2050 2.2386 0.28 113.22 0.00067 0.26919 0.3321 0.2073 2.0865 1.27 113.56 0.00301 0.26811 0.3329 0.2094 1.9540 2.22 113.88 0.00522 0.26711 0.3337 0.2115 1.8375 3.11 114.19 0.00730 0.26617 0.3345 0.2135 1.7343 3.97 114.47 0.00928 0.26530 0.3352 0.2154 1.6422 4.79 114.74 0.01116 0.26448 0.3360 0.2173 1.5594 5.57 115.00 0.01296 0.26371 0.3367 0.2191 1.4847 6.33 115.24 0.01467 0.26297 0.3374 0.2208 1.4168 7.06 115.47 0.01632 0.26228 0.3382 0.2226 1.3549 7.76 115.69 0.01791 0.26162 0.3389 0.2242 1.2982 8.45 115.90 0.01943 0.26098 0.3396 0.2259 1.2460 9.11 116.10 0.02090 0.26038 0.3403 0.2275 1.1979 9.75 116.30 0.02232 0.25980 0.3410 0.2290 1.0925 11.27 116.75 0.02568 0.25845 0.3427 0.2328 1.0040 12.70 117.16 0.02880 0.25722 0.3445 0.2365 0.9287 14.05 117.53 0.03171 0.25610 0.3462 0.2400 0.8638 15.33 117.88 0.03444 0.25505 0.3478 0.2434 0.8073 16.54 118.20 0.03702 0.25408 0.3495 0.2467 0.7576 17.70 118.49 0.03946 0.25316 0.3512 0.2499 0.7135 18.81 118.77 0.04178 0.25231 0.3528 0.2531 0.6742 19.88 119.02 0.04400 0.25149 0.3545 0.2562 0.6389 20.91 119.26 0.04611 0.25072 0.3561 0.2592 0.6070 21.90 119.48 0.04815 0.24999 0.3578 0.2622 0.5515 23.79 119.89 0.05198 0.24862 0.3611 0.2681 0.5051 25.57 120.24 0.05555 0.24736 0.3644 0.2738 0.4655 27.25 120.56 0.05890 0.24618 0.3678 0.2795 0.4314 28.85 120.83 0.06205 0.24508 0.3712 0.2852 0.4016 30.38 121.08 0.06503 0.24403 0.3746 0.2908 0.3755 31.85 121.29 0.06787 0.24304 0.3781 0.2965 0.3523 33.27 121.48 0.07057 0.24210 0.3816 0.3022 0.3316 34.63 121.65 0.07316 0.24119 0.3851 0.3080 0.3130 35.95 121.79 0.07565 0.24031 0.3888 0.3139 0.2962 37.22 121.91 0.07804 0.23946 0.3925 0.3200 0.2669 39.67 122.09 0.08258 0.23783 0.4001 0.3325 0.2424 41.99 122.20 0.08683 0.23628 0.4081 0.3457 0.2215 44.21 122.25 0.09084 0.23478 0.4165 0.3599 0.2034 46.34 122.24 0.09464 0.23333 0.4255 0.3751 0.1876 48.40 122.18 0.09827 0.23190 0.4350 0.3915 0.1736 50.38 122.07 0.10175 0.23049 0.4452 0.4094 0.1613 52.31 121.91 0.10509 0.22909 0.4564 0.4290 0.1501 54.19 121.70 0.10832 0.22769 0.4685 0.4507 0.1401 56.03 121.44 0.11145 0.22629 0.4820 0.4747 0.1310 57.83 121.13 0.11450 0.22488 0.4971 0.5016 0.1114 62.23 120.14 0.12182 0.22124 0.5443 0.5857 0.0952 66.54 118.80 0.12888 0.21732 0.6143 0.7083 0.0814 70.89 117.02 0.13590 0.21295 0.7303 0.9059 0.0690 75.47 114.59 0.14320 0.20777 0.9603 1.2829 0.0293 90.97 90.97 0.16781 0.16781 — —

Bubble and dew points at one standard atmosphere

c

cp /cv Vapor 1.228 1.227 1.227 1.228 1.228 1.229 1.230 1.232 1.233 1.234 1.237 1.240 1.243 1.244 1.245 1.248 1.251 1.254 1.256 1.259 1.261 1.264 1.267 1.269 1.272 1.274 1.277 1.279 1.282 1.284 1.287 1.289 1.295 1.301 1.308 1.314 1.320 1.326 1.333 1.339 1.345 1.352 1.365 1.378 1.392 1.406 1.420 1.435 1.451 1.467 1.483 1.500 1.537 1.576 1.619 1.665 1.716 1.772 1.833 1.901 1.977 2.063 2.333 2.728 3.367 4.579 —

Refrigerants

Pressure, psia 1 1.5 2 2.5 3 4 5 6 7 8 10 12 14 14.70b 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 55 60 65 70 75 80 85 90 95 100 110 120 130 140 150 160 170 180 190 200 220 240 260 280 300 320 340 360 380 400 450 500 550 600 692.78c

R-410A [R-32/125 (50/50)] Properties of Liquid on Bubble Line and Vapor on Dew Line [2013F, Ch 30, Tbl R-410A]

Critical point

127

further reprodu


Refrigerants



128

further reprodu


Table 9.11 R-507A [R-125/143a (50/50)] Properties of Saturated Liquid and Saturated Vapor [2013F, Ch 30, Tbl R-507A] Enthalpy, Pres- Density, Volume, Btu/lb ft3/lb sure,** lb/ft3 Liquid Vapor psia Liquid Vapor 0.386 92.41 86.952 –32.027 67.009 0.497 91.88 68.522 –30.571 67.711 0.634 91.36 54.501 –29.121 68.416 0.801 90.84 43.729 –27.677 69.126 1.004 90.32 35.377 –26.235 69.838 1.249 89.80 28.844 –24.796 70.554 1.541 89.29 23.692 –23.359 71.272 1.887 88.77 19.596 –21.921 71.993 2.295 88.26 16.315 –20.484 72.716 2.773 87.75 13.669 –19.045 73.440 3.329 87.23 11.521 –17.604 74.166 3.974 86.72 9.7644 –16.161 74.892 4.715 86.20 8.3201 –14.716 75.619 5.566 85.68 7.1254 –13.266 76.346 6.535 85.16 6.1316 –11.813 77.073 7.636 84.64 5.3004 –10.356 77.800 8.879 84.11 4.6018 –8.894 78.525 10.280 83.58 4.0116 –7.427 79.248 11.849 83.05 3.5108 –5.954 79.970 13.603 82.51 3.0839 –4.475 80.690 14.696 82.20 2.8676 –3.625 81.101 15.554 81.97 2.7184 –2.990 81.406 17.719 81.43 2.4043 –1.499 82.119 20.112 80.88 2.1331 0.000 82.829 22.750 80.33 1.8983 1.506 83.534 25.649 79.77 1.6941 3.020 84.235 28.827 79.20 1.5160 4.541 84.931 32.300 78.63 1.3601 6.071 85.621 36.086 78.05 1.2231 7.610 86.304 40.203 77.46 1.1025 9.158 86.981 44.671 76.87 0.9960 10.716 87.651 49.508 76.27 0.9016 12.284 88.313 54.733 75.66 0.8177 13.862 88.966 60.367 75.04 0.7430 15.452 89.610 66.429 74.41 0.6763 17.052 90.245 72.941 73.77 0.6165 18.665 90.868 79.923 73.12 0.5629 20.290 91.480 87.396 72.45 0.5146 21.929 92.079 95.384 71.78 0.4711 23.581 92.664 103.91 71.09 0.4318 25.249 93.234 112.99 70.38 0.3962 26.931 93.788 122.65 69.66 0.3638 28.630 94.324 132.92 68.92 0.3344 30.346 94.840 143.82 68.16 0.3076 32.080 95.336 155.38 67.39 0.2832 33.834 95.808 167.62 66.58 0.2608 35.609 96.255 180.56 65.76 0.2403 37.406 96.675 194.24 64.90 0.2214 39.228 97.065 208.68 64.02 0.2041 41.076 97.421 223.92 63.10 0.1880 42.952 97.740 239.97 62.14 0.1732 44.860 98.019 256.88 61.14 0.1595 46.803 98.251 274.68 60.09 0.1468 48.784 98.431 293.40 58.99 0.1349 50.809 98.551 313.08 57.82 0.1238 52.885 98.600 333.77 56.57 0.1134 55.018 98.568 355.50 55.22 0.1036 57.221 98.435 378.33 53.76 0.0943 59.509 98.177 402.31 52.15 0.0855 61.903 97.759 427.52 50.32 0.0769 64.439 97.125 454.04 48.19 0.0684 67.182 96.173 481.99 45.55 0.0597 70.265 94.697 511.55 41.76 0.0499 74.107 92.081 537.40 30.64 0.0326 83.010 83.010

Specific Heat cp , Btu/lb·°F cp /cv Vapor Liquid Vapor Vapor 0.23154 0.2919 0.1470 1.1650 0.22872 0.2904 0.1487 1.1637 0.22607 0.2893 0.1504 1.1626 0.22358 0.2885 0.1522 1.1616 0.22125 0.2879 0.1540 1.1607 0.21906 0.2876 0.1558 1.1599 0.21701 0.2874 0.1576 1.1593 0.21509 0.2874 0.1595 1.1588 0.21328 0.2875 0.1614 1.1584 0.21159 0.2878 0.1633 1.1581 0.21001 0.2882 0.1652 1.1580 0.20852 0.2887 0.1672 1.1581 0.20713 0.2893 0.1692 1.1583 0.20583 0.2900 0.1712 1.1586 0.20462 0.2908 0.1733 1.1592 0.20348 0.2917 0.1754 1.1599 0.20242 0.2926 0.1776 1.1607 0.20143 0.2937 0.1798 1.1618 0.20050 0.2948 0.1821 1.1631 0.19963 0.2960 0.1844 1.1646 0.19916 0.2967 0.1858 1.1655 0.19882 0.2972 0.1868 1.1663 0.19807 0.2985 0.1893 1.1682 0.19737 0.30000 0.1918 1.1704 0.19671 0.3014 0.1944 1.1728 0.19610 0.3030 0.1971 1.1755 0.19553 0.3046 0.1998 1.1785 0.19500 0.3063 0.2026 1.1818 0.19450 0.3081 0.2056 1.1854 0.19404 0.3100 0.2086 1.1894 0.19360 0.3119 0.2117 1.1938 0.19319 0.3140 0.2149 1.1986 0.19281 0.3161 0.2183 1.2038 0.19245 0.3184 0.2218 1.2095 0.19211 0.3208 0.2254 1.2157 0.19179 0.3233 0.2291 1.2226 0.19148 0.3260 0.2330 1.2301 0.19118 0.3288 0.2371 1.2384 0.19089 0.3318 0.2414 1.2476 0.19061 0.3350 0.2460 1.2577 0.19032 0.3384 0.2508 1.2690 0.19004 0.3421 0.2560 1.2816 0.18976 0.3460 0.2616 1.2956 0.18946 0.3503 0.2676 1.3113 0.18916 0.3549 0.2742 1.3289 0.18884 0.3599 0.2814 1.3488 0.18850 0.3654 0.2894 1.3713 0.18814 0.3715 0.2983 1.3970 0.18775 0.3783 0.3083 1.4265 0.18732 0.3858 0.3196 1.4606 0.18686 0.3944 0.3325 1.5003 0.18634 0.4043 0.3475 1.5471 0.18576 0.4157 0.3650 1.6029 0.18511 0.4291 0.3858 1.6706 0.18438 0.4453 0.4112 1.7541 0.18354 0.4652 0.4427 1.8597 0.18256 0.4904 0.4833 1.9972 0.18141 0.5237 0.5375 2.1831 0.18003 0.5700 0.6142 2.4480 0.17833 0.6399 0.7313 2.8546 0.17616 0.7590 0.9326 3.5556 0.17318 1.0130 1.3606 5.0420 0.16842 1.9550 2.8693 10.2379 0.15339   

Entropy, Btu/lb·°F Liquid –0.08831 –0.08365 –0.07908 –0.07460 –0.07019 –0.06586 –0.06160 –0.05740 –0.05326 –0.04918 –0.04515 –0.04117 –0.03723 –0.03335 –0.02950 –0.02569 –0.02192 –0.01819 –0.01449 –0.01082 –0.00873 –0.00719 –0.00358 0.00000 0.00355 0.00708 0.01058 0.01407 0.01753 0.02097 0.02439 0.02779 0.03118 0.03455 0.03791 0.04126 0.04459 0.04791 0.05123 0.05454 0.05784 0.06114 0.06444 0.06773 0.07103 0.07434 0.07764 0.08096 0.08429 0.08764 0.09101 0.09441 0.09784 0.10130 0.10482 0.10840 0.11206 0.11583 0.11973 0.12382 0.12821 0.13311 0.13918 0.15339

*Temperatures on ITS-90 scale **Small deviations from azeotropic behavior occur at some conditions; tabulated pressures are average of bubble and dew-point pressures

Refrigerants

Temp.,* °F –150 –145 –140 –135 –130 –125 –120 –115 –110 –105 –100 –95 –90 –85 –80 –75 –70 –65 –60 –55 –52.13b –50 –45 –40 –35 –30 –25 –20 –15 –10 –5 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 155 159.12c

b Normal c

boiling point Critical point

129

further reprodu


Refrigerants


Figure 9.9 Pressure-Enthalpy Diagram for Refrigerant 1234yf [2013F, Ch 30, Fig 12]

130

further reprodu


Table 9.12 R-1234yf (2,3,3,3-Tetrafluoroprop-1-ene) Properties of Saturated Liquid and Saturated Vapor [2013F, Ch 30, Tbl R-1234yf] Pres- Density, Volume, lb/ft3 sure, ft3/lb psia Liquid Vapor 5.111 82.49 7.1955 5.932 82.03 6.2622 6.855 81.58 5.4710 7.889 81.11 4.7974 9.046 80.65 4.2215 10.333 80.18 3.7271 11.761 79.71 3.3012 13.341 79.23 2.9329 14.696 78.85 2.6781 15.084 78.75 2.6132 17.001 78.26 2.3349 19.104 77.77 2.0917 21.404 77.28 1.8786 23.914 76.78 1.6913 26.647 76.27 1.5262 29.615 75.76 1.3802 32.831 75.24 1.2508 36.309 74.72 1.1357 40.062 74.19 1.0332 44.105 73.65 0.9416 48.451 73.11 0.8596 53.116 72.55 0.7860 58.113 71.99 0.7198 63.459 71.42 0.6601 69.167 70.84 0.6062 75.255 70.25 0.5573 81.737 69.65 0.5130 88.629 69.04 0.4728 95.949 68.42 0.4361 103.71 67.78 0.4027 111.94 67.14 0.3721 120.64 66.47 0.3441 129.84 65.80 0.3185 139.55 65.10 0.2949 149.80 64.39 0.2732 160.60 63.66 0.2532 171.97 62.92 0.2347 183.93 62.14 0.2176 196.51 61.35 0.2017 209.72 60.52 0.1870 223.59 59.66 0.1733 238.13 58.77 0.1606 253.39 57.83 0.1487 269.37 56.84 0.1375 286.11 55.80 0.1270 303.64 54.68 0.1172 321.99 53.49 0.1078 341.19 52.21 0.0990 361.28 50.80 0.0905 382.32 49.24 0.0823 404.35 47.47 0.0743 427.45 45.39 0.0662 451.72 42.73 0.0578 477.33 38.53 0.0475 490.55 29.69 0.0337


Enthalpy, Btu/lb Liquid –5.458 –4.109 –2.749 –1.380 0.000 1.390 2.790 4.200 5.315 5.621 7.053 8.495 9.948 11.412 12.887 14.374 15.871 17.381 18.902 20.434 21.979 23.536 25.106 26.688 28.283 29.891 31.513 33.149 34.799 36.463 38.142 39.837 41.548 43.275 45.021 46.784 48.568 50.373 52.201 54.054 55.935 57.845 59.789 61.769 63.792 65.861 67.986 70.175 72.445 74.816 77.328 80.050 83.145 87.241 93.995

Vapor 76.593 77.395 78.198 79.002 79.808 80.614 81.420 82.226 82.859 83.032 83.837 84.641 85.444 86.244 87.043 87.839 88.632 89.422 90.208 90.989 91.765 92.536 93.301 94.059 94.810 95.552 96.285 97.008 97.720 98.420 99.106 99.779 100.435 101.075 101.696 102.296 102.874 103.428 103.955 104.452 104.916 105.342 105.726 106.061 106.340 106.554 106.690 106.731 106.653 106.421 105.976 105.213 103.888 101.103 93.995 b

Entropy, Btu/lb·°F Liquid –0.01330 –0.00995 –0.00662 –0.00330 0.00000 0.00328 0.00655 0.00981 0.01236 0.01305 0.01628 0.01949 0.02269 0.02588 0.02906 0.03223 0.03538 0.03853 0.04166 0.04479 0.04790 0.05101 0.05411 0.05720 0.06029 0.06337 0.06644 0.06951 0.07257 0.07563 0.07869 0.08174 0.08479 0.08784 0.09090 0.09395 0.09701 0.10008 0.10315 0.10624 0.10934 0.11246 0.11561 0.11879 0.12200 0.12526 0.12857 0.13196 0.13543 0.13903 0.14281 0.14688 0.15147 0.15752 0.16763


Vapor 0.19200 0.19146 0.19097 0.19055 0.19017 0.18984 0.18956 0.18932 0.18916 0.18912 0.18896 0.18883 0.18874 0.18868 0.18865 0.18865 0.18867 0.18872 0.18878 0.18887 0.18898 0.18910 0.18924 0.18939 0.18955 0.18972 0.18989 0.19007 0.19025 0.19044 0.19062 0.19079 0.19096 0.19112 0.19126 0.19140 0.19151 0.19160 0.19167 0.19171 0.19171 0.19167 0.19158 0.19144 0.19122 0.19093 0.19053 0.19001 0.18933 0.18844 0.18725 0.18561 0.18315 0.17853 0.16763

Specific Heat, cp Btu/lb·°F Liquid 0.2688 0.2707 0.2727 0.2746 0.2766 0.2787 0.2807 0.2828 0.2844 0.2848 0.2870 0.2891 0.2912 0.2934 0.2956 0.2979 0.3001 0.3024 0.3048 0.3072 0.3096 0.3121 0.3147 0.3173 0.3199 0.3227 0.3255 0.3285 0.3315 0.3346 0.3379 0.3413 0.3450 0.3488 0.3530 0.3574 0.3623 0.3676 0.3735 0.3801 0.3875 0.3959 0.4055 0.4167 0.4300 0.4459 0.4655 0.4906 0.5241 0.5717 0.6458 0.7788 1.094 — 

Vapor 0.1776 0.1796 0.1817 0.1838 0.1859 0.1880 0.1903 0.1925 0.1943 0.1948 0.1971 0.1995 0.2019 0.2043 0.2068 0.2094 0.2120 0.2147 0.2174 0.2202 0.2231 0.2261 0.2291 0.2323 0.2355 0.2389 0.2425 0.2462 0.2501 0.2543 0.2587 0.2635 0.2686 0.2742 0.2802 0.2867 0.2940 0.3019 0.3107 0.3206 0.3318 0.3446 0.3594 0.3767 0.3974 0.4227 0.4544 0.4956 0.5513 0.6314 0.7571 0.9837 1.5170 —  c

cp /cv Vapor 1.1241 1.1243 1.1247 1.1252 1.1258 1.1265 1.1274 1.1285 1.1294 1.1297 1.1310 1.1325 1.1342 1.1361 1.1381 1.1404 1.1429 1.1457 1.1486 1.1519 1.1555 1.1594 1.1637 1.1685 1.1736 1.1793 1.1856 1.1926 1.2002 1.2087 1.2181 1.2286 1.2402 1.2533 1.2679 1.2843 1.3028 1.3239 1.3479 1.3756 1.4077 1.4453 1.4898 1.5432 1.6082 1.6891 1.7922 1.9275 2.1127 2.3809 2.8031 3.5641 5.3442 — 

Refrigerants

Temp.,* °F –60 –55 –50 –45 –40 –35 –30 –25 –21.07b –20 –15 –10 –5 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 202.46c

Critical point 131

further reprodu


Refrigerants


Figure 9.10 Pressure-Enthalpy Diagram for Refrigerant 1234ze(E) [2013F, Ch 30, Fig 13]

132

further reprodu


Table 9.13

Enthalpy, Pres- Density, Volume, Btu/lb sure, lb/ft3 ft3/lb psia Liquid Vapor Liquid Vapor 2.845 85.94 13.049 –5.694 85.631 3.352 85.51 11.195 –4.282 86.455 3.930 85.08 9.6481 –2.862 87.280 4.588 84.64 8.3497 88.107 –1.435 5.332 84.20 7.2553 0.000 88.935 6.170 83.75 6.3287 1.443 89.763 7.112 83.31 5.5409 2.893 90.592 8.167 82.86 4.8682 4.352 91.421 9.343 82.40 4.2916 5.819 92.250 10.651 81.94 3.7955 7.294 93.078 12.100 81.48 3.3671 8.777 93.906 13.702 81.02 2.9958 10.268 94.732 14.696 80.75 2.8048 11.130 95.206 15.467 80.55 2.6730 11.768 95.556 17.406 80.07 2.3914 13.277 96.379 19.531 79.59 2.1449 14.794 97.199 24.386 78.62 1.7381 17.855 98.832 27.141 78.13 1.5699 19.399 99.643 30.132 77.63 1.4211 20.953 100.451 33.372 77.12 1.2890 22.516 101.255 36.874 76.61 1.1714 24.088 102.055 40.651 76.09 1.0665 25.670 102.849 44.719 75.56 0.9727 27.262 103.638 49.090 75.03 0.8887 28.864 104.422 53.781 74.49 0.8132 30.477 105.199 58.805 73.95 0.7452 32.100 105.970 64.178 73.39 0.6839 33.733 106.733 69.914 72.83 0.6285 35.378 107.488 76.031 72.26 0.5783 37.034 108.235 82.543 71.68 0.5327 38.702 108.973 89.468 71.09 0.4913 40.381 109.701 96.821 70.49 0.4535 42.073 110.418 104.62 69.87 0.4191 43.778 111.124 112.88 69.25 0.3876 45.497 111.818 121.62 68.62 0.3588 47.229 112.498 130.86 67.97 0.3324 48.977 113.164 140.62 67.30 0.3081 50.741 113.814 150.91 66.62 0.2857 52.523 114.447 161.75 65.92 0.2651 54.323 115.062 173.17 65.21 0.2460 56.142 115.655 185.19 64.46 0.2284 57.983 116.227 197.81 63.70 0.2121 59.847 116.773 211.08 62.90 0.1970 61.735 117.291 225.00 62.08 0.1829 63.648 117.778 239.60 61.22 0.1698 65.590 118.230 254.91 60.32 0.1575 67.561 118.643 270.94 59.38 0.1461 69.564 119.012 287.74 58.39 0.1353 71.602 119.330 305.31 57.36 0.1252 73.679 119.590 323.71 56.26 0.1157 75.802 119.783 342.95 55.09 0.1067 77.977 119.896 363.09 53.84 0.0981 80.217 119.913 384.16 52.47 0.0899 82.537 119.810 406.20 50.96 0.0819 84.962 119.553 429.29 49.25 0.0742 87.528 119.088 453.47 47.25 0.0664 90.298 118.319 478.86 44.75 0.0584 93.404 117.046 505.59 41.14 0.0493 97.247 114.672 527.39 30.54 0.0327 105.815 105.815


b

Entropy, Btu/lb·°F Liquid –0.01389 –0.01038 –0.00690 –0.00344 0.00000 0.00341 0.00680 0.01017 0.01352 0.01685 0.02016 0.02345 0.02534 0.02672 0.02998 0.03322 0.03964 0.04283 0.04600 0.04916 0.05231 0.05544 0.05856 0.06167 0.06476 0.06785 0.07092 0.07398 0.07704 0.08008 0.08312 0.08615 0.08917 0.09219 0.09520 0.09821 0.10122 0.10424 0.10725 0.11027 0.11329 0.11633 0.11937 0.12243 0.12551 0.12860 0.13171 0.13485 0.13803 0.14124 0.14450 0.14783 0.15125 0.15479 0.15851 0.16249 0.16693 0.17239 0.18470


Vapor 0.21461 0.21385 0.21314 0.21250 0.21192 0.21139 0.21091 0.21049 0.21011 0.20977 0.20948 0.20922 0.20909 0.20900 0.20882 0.20867 0.20846 0.20839 0.20836 0.20834 0.20835 0.20837 0.20842 0.20848 0.20855 0.20864 0.20874 0.20885 0.20897 0.20910 0.20923 0.20937 0.20950 0.20964 0.20978 0.20991 0.21003 0.21015 0.21025 0.21035 0.21042 0.21047 0.21050 0.21049 0.21046 0.21037 0.21024 0.21006 0.20980 0.20946 0.20902 0.20846 0.20775 0.20683 0.20564 0.20402 0.20171 0.19784 0.18470

Specific Heat, cp Btu/lb·°F Liquid 0.2816 0.2831 0.2846 0.2861 0.2876 0.2891 0.2907 0.2923 0.2939 0.2955 0.2971 0.2988 0.2997 0.3005 0.3022 0.3039 0.3074 0.3092 0.3111 0.3130 0.3149 0.3168 0.3188 0.3209 0.3230 0.3251 0.3273 0.3296 0.3320 0.3344 0.3369 0.3396 0.3424 0.3454 0.3486 0.3520 0.3557 0.3597 0.3641 0.3689 0.3740 0.3797 0.3859 0.3927 0.4002 0.4085 0.4179 0.4286 0.4412 0.4564 0.4754 0.4999 0.5327 0.5791 0.6495 0.7699 1.027 — 

Vapor 0.1749 0.1765 0.1782 0.1798 0.1815 0.1832 0.1850 0.1868 0.1886 0.1904 0.1923 0.1943 0.1954 0.1963 0.1983 0.2004 0.2047 0.2069 0.2093 0.2116 0.2141 0.2166 0.2192 0.2218 0.2246 0.2274 0.2304 0.2335 0.2367 0.2400 0.2435 0.2471 0.2510 0.2550 0.2593 0.2638 0.2686 0.2738 0.2793 0.2853 0.2918 0.2990 0.3070 0.3159 0.3261 0.3379 0.3518 0.3684 0.3884 0.4131 0.4442 0.4846 0.5391 0.6165 0.7354 0.9416 1.3857 —  c

cp /cv Vapor 1.1187 1.1186 1.1186 1.1188 1.1190 1.1193 1.1198 1.1204 1.1210 1.1219 1.1228 1.1239 1.1246 1.1251 1.1265 1.1280 1.1316 1.1336 1.1359 1.1384 1.1410 1.1440 1.1471 1.1506 1.1544 1.1584 1.1629 1.1677 1.1730 1.1787 1.1850 1.1918 1.1993 1.2076 1.2166 1.2266 1.2376 1.2498 1.2635 1.2789 1.2962 1.3160 1.3387 1.3649 1.3956 1.4316 1.4745 1.5260 1.5889 1.6670 1.7661 1.8954 2.0709 2.3216 2.7077 3.3761 4.8045 — 

Refrigerants

Temp.,* °F –60 –55 –50 –45 –40 –35 –30 –25 –20 –15 –10 –5 –2.13b 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 228.87c

R-1234ze(E) (Trans-1,3,3,3-Tetrafluoropropene) Properties of Saturated Liquid and Saturated Vapor [2013F, Ch 30, Tbl 1234ze(E)]

Critical point

133

further reprodu

Evaporator –25°F/Condenser 86°F 744 Carbon dioxide 170 Ethane 1270 Propylene 507A R-125/143a (50/50) 404A R-125/143a/134a (44/52/4) 502 R-22/115 (48.8/51.2) 22 Chlorodifluoromethane 717 Ammonia Evaporator 20°F/Condenser 86°F 744 Carbon dioxide 170 Ethane 32 Difluoromethane 410A R-32/125 (50/50) 507A R-125/143a (50/50) 404A R-125/143a/134a (44/52/4) 1270 Propylene 502 R-22/115 (48.8/51.2) 22 Chlorodifluoromethane 407C R-32/125/134a (23/25/52) 290 Propane 717 Ammonia 1234yf 2,3,3,3-tetrafluoropropene*

No.

1046.2 675.1 189.3 211.7 206.1 189.2 172.9 169.3 1046.2 675.1 279.6 273.6 211.7 206.1 189.3 189.2 172.9 183.7 156.5 169.3 113.6

195.7 146.8 28.8 28.8 27.6 26.5 22.1 16.0 421.9 293.6 94.7 93.2 72.9 70.5 69.1 66.3 57.8 57.5 55.8 48.2 36.3

2.48 2.3 2.95 2.94 2.9 2.92 2.74 2.86 2.99 3.19 2.8 3.51 3.13

5.35 4.6 6.57 7.34 7.46 7.14 7.81 10.61 55.7 70.1 111.2 73.5 49.4 51.1 126.6 47.1 71.3 71.9 124.1 478.5 51.8

56.8 66.0 115.7 43.5 45.1 42.1 66.8 463.9 3.59 2.85 1.80 2.72 4.05 3.92 1.58 4.25 2.80 2.78 1.61 0.42 3.86

3.52 3.03 1.73 4.60 4.44 4.76 3.00 0.43 0.726 1.238 0.229 0.316 0.476 0.46 0.381 0.429 0.287 0.296 0.399 0.084 0.43

0.711 1.314 0.416 0.54 0.521 0.48 0.307 0.087 0.203 0.421 0.902 0.651 0.616 0.649 1.58 0.619 0.935 0.942 1.89 5.91 1.15

0.457 0.878 3.63 1.52 1.61 1.48 2.32 16.7 0.73 1.20 1.62 1.77 2.50 2.54 2.50 2.63 2.62 2.62 3.05 2.47 4.44

1.61 2.66 6.28 6.98 7.13 7.06 6.95 7.19 1.342 1.314 0.797 0.815 0.848 0.842 0.79 0.813 0.772 0.795 0.787 0.754 0.809

2.779 2.805 1.637 1.833 1.817 1.722 1.589 1.569

3.514 3.588 5.924 5.78 5.564 5.598 5.975 5.799 6.105 5.93 5.987 6.254 5.835

1.698 1.681 2.88 2.573 2.595 2.739 2.967 3.007

142.3 115.8 139.4 115.8 93.5 94.3 102.8 95.8 118.0 111.0 94.8 179.8 86.0

196.3 136.2 120.3 100.6 102.1 106.3 149.8 285.6

ComSpecific Power Net Evaporator Condenser ComCoefficient pressor Refrigerant Liquid Volume of Compressor ConsumpRefrigerating Pressure, Pressure, pression of Circulated, Circulated, Suction Displacement, Discharge tion, Effect, Chemical Name or psia psia Ratio ft3/min Performance Temp., lb/min gal/min Gas, hp Btu/lb Composition (% by mass) °F ft3/lb

Refrigerant

Table 9.14 Comparative Refrigerant Performance per Ton of Refrigeration [2013F, Ch 29, Tbl 8]

Refrigerants



134

further reprodu

Refrigerant

58.7 279.6 273.6 189.2 183.7 172.9 156.5 169.3 127.6 113.6 107.9 111.7 83.9 58.7 41.1 15.9 7.9

17.9 147.7 145.0 102.0 92.8 90.8 85.3 81.0 66.5 58.1 56.3 54.7 40.6 29.2 19.5 6.5 3.1

111.7 83.9

33.1 24.4

Refrigerants

3.37

2.01 2.11 2.44 2.57

2.06

1.89 1.89 1.85 1.98 1.9 1.84 2.09 1.92 1.96 1.92 2.04

3.29

3.44

65.8

127.4 140.5 66.9 59.2

64.1

112.2 75.2 49.6 74.7 73.5 130.7 484.9 64.7 55.5 54.6 69.2

119.5

60.0

3.04

1.57 1.42 2.99 3.38

3.12

1.78 2.66 4.03 2.68 2.72 1.53 0.41 3.09 3.61 3.67 2.89

1.67

3.33

0.307

0.345 0.301 0.246 0.26

0.327

0.223 0.308 0.407 0.284 0.279 0.379 0.083 0.331 0.402 0.34 0.292

0.368

0.349

1.41

3.01 4.57 5.3 9.41

1.07

0.577 0.416 0.404 0.588 0.604 1.26 3.61 0.725 0.726 0.719 0.868

4.78

1.74

*Superheat required Source: Data from NIST CYCLE_D 4.0, zero subcool, zero superheat unless noted, no line losses, 100% efficiencies, average temperatures.

1234ze(E)

Tetrafluoroethane Trans-1,3,3,3tetrafluoropropene* 600a Isobutane* Evaporator 45°F/Condenser 86°F 32 Difluoromethane 410A R-32/125 (50/50) 502 R-22/115 (48.8/51.2) 407C R-32/125/134a (23/25/52) 22 Chlorodifluoromethane 290 Propane 717 Ammonia 500 R-12/152a (73.8/26.2) 1234yf 2,3,3,3-tetrafluoropropene* 12 Dichlorodifluoromethane 134a Tetrafluoroethane Trans-1,3,3,31234ze(E) tetrafluoropropene* 600a Isobutane* 600 Butane* 123 Dichlorotrifluoroethane 113 Trichlorotrifluoroethane*

No.

134a

Comparative Refrigerant Performance per Ton of Refrigeration [2013F, Ch 29, Tbl 8] (Continued)

4.72 6.50 15.85 31.81

3.34

1.03 1.11 1.63 1.57 1.64 1.92 1.49 2.24 2.62 2.64 2.51

7.99

5.81

4.28

0.425 0.42 0.414 0.413

0.433

0.445 0.455 0.451 0.443 0.433 0.439 0.421 0.432 0.444 0.429 0.433

0.764

0.782

0.778

11.084 11.226 11.397 11.409

10.899

10.602 10.379 10.474 10.655 10.885 10.743 11.186 10.925 10.623 11.004 10.903

6.171

6.03

6.063

86.0 86.0 86.0 86.0

86.0

116.4 103.7 91.8 102.7 104.5 90.7 137.4 94.2 86.0 91.6 90.6

86.0

86.0

94.7

ComSpecific Power Net Evaporator Condenser ComCoefficient pressor Refrigerant Liquid Volume of Compressor ConsumpRefrigerating Pressure, Pressure, pression of Circulated, Circulated, Suction Displacement, Discharge tion, Effect, Chemical Name or psia psia Ratio ft3/min Performance Temp., lb/min gal/min Gas, hp Btu/lb Composition (% by mass) °F ft3/lb

Table 9.14



135

further reprodu

1/2 5/8 3/4 7/8 1 1/8 1 3/8 1 5/8 2 1/8 2 5/8 3 1/8 3 5/8 4 1/8 5 1/8 6 1/8 8 1/8

Type L Copper, OD

Line Size

Suction Lines ( t = 2°F) Saturated Suction Temperature, °F –40 –20 0 20

Corresponding  p, psi/100 ft 0.97 1.41 1.96 2.62 0.09 0.15 0.24 0.36 0.16 0.28 0.44 0.68 0.28 0.47 0.76 1.15 0.43 0.73 1.17 1.78 0.88 1.49 2.37 3.61 1.54 2.59 4.13 6.28 2.44 4.10 6.53 9.92 5.07 8.52 13.53 20.51 8.97 15.07 23.88 36.16 14.34 24.02 38.05 57.56 21.31 35.73 56.53 85.39 30.09 50.32 79.66 120.39 53.85 89.97 142.32 214.82 86.74 144.47 228.50 344.70 179.88 299.39 472.46 710.75

–60

0.64 0.05 0.09 0.15 0.24 0.49 0.86 1.36 2.83 5.03 8.05 11.98 16.93 30.35 48.89 101.60

p = 17.4 6.09 11.39 18.87 29.81 60.17 104.41 164.68 339.46 597.42 950.09 1407.96 1982.40 3525.99 5648.67 11660.71

t = 5°F Drop

Liquid Lines See note a

40 Velocity  t = 1°F Drop Corresponding  p, psi/100 ft = 3.44 3.55 3.55 3.55 3.55 3.55 3.55 100 fpm  p = 3.6 0.53 0.56 0.61 0.65 0.70 0.75 0.79 1.3 2.6 1.00 1.04 1.14 1.23 1.31 1.40 1.48 2.1 4.9 1.70 1.77 1.93 2.09 2.23 2.38 2.51 3.1 8.1 2.63 2.73 2.98 3.22 3.44 3.66 3.87 4.4 12.8 5.31 5.52 6.01 6.49 6.96 7.40 7.81 7.5 25.9 9.23 9.60 10.46 11.29 12.10 12.87 13.58 11.4 45.2 14.57 15.14 16.49 17.80 19.07 20.28 21.41 16.1 71.4 30.06 31.29 34.08 36.80 39.43 41.93 44.26 28.0 147.9 52.96 55.04 59.95 64.74 69.36 73.76 77.85 43.2 261.2 84.33 87.66 95.48 103.11 110.47 117.48 124.00 61.7 416.2 125.18 129.88 141.46 152.76 163.67 174.05 183.71 83.5 618.4 176.20 182.83 199.13 215.05 230.40 245.01 258.61 108.5 871.6 313.91 325.75 354.81 383.16 410.51 436.55 460.78 169.1 1554.2 502.77 521.74 568.28 613.69 657.49 699.20 738.00 243.1 2497.7 1037.34 1076.62 1172.66 1266.36 1356.75 1442.81 1522.89 424.6 5159.7 40

Discharge Lines ( t = 1°F,  p = 3.55 psi) Saturated Suction Temperature, °F –60 –40 –20 0 20

Table 9.15 Suction, Discharge, and Liquid Line Capacities in Tons for Refrigerant 404A (Single- or High-Stage Applications) [2010R, Ch 1, Tbl 6]

Refrigerants



136

further reprodu

Steel IPS SCH 3/8 80 1/2 80 3/4 80 1 80 1 1/4 80 1 1/2 80 2 40 2 1/2 40 3 40 4 40 5 40 6 40 8 40 10 40 12 IDb 14 30 16 30

Type L Copper, OD

0.04 0.08 0.18 0.35 0.75 1.14 2.65 4.23 7.48 15.30 27.58 44.58 91.40 165.52 264.36 342.81 493.87

0.64

–60

0.07 0.14 0.31 0.60 1.30 1.98 4.61 7.34 12.98 26.47 47.78 77.26 158.09 286.19 457.37 592.13 852.84

3.44

40

0.11 0.18 0.27 0.39 0.22 0.35 0.53 0.76 0.51 0.79 1.18 1.71 0.99 1.55 2.32 3.36 2.13 3.33 4.97 7.20 3.26 5.08 7.57 10.96 7.55 11.78 17.57 25.45 12.04 18.74 27.94 40.49 21.26 33.11 49.37 71.55 43.34 67.50 100.66 145.57 78.24 121.87 181.32 262.52 126.52 197.09 293.24 424.04 258.81 402.66 599.91 867.50 468.14 728.40 1083.73 1569.40 748.94 1163.62 1733.87 2507.30 968.21 1506.59 2244.98 3246.34 1395.24 2171.13 3230.27 4678.48

Suction Lines ( t = 2°F) Saturated Suction Temperature, °F –40 –20 0 20 Corresponding  p, psi/100 ft 0.97 1.41 1.96 2.62

Refrigerants

Line Size

0.40 0.79 1.78 3.48 7.45 11.35 26.36 41.93 74.10 150.75 272.21 439.72 898.42 1625.34 2600.54 3362.07 4845.26

0.44 0.86 1.93 3.79 8.12 12.37 28.71 45.67 80.71 164.20 296.49 478.94 978.56 1770.31 2832.50 3661.96 5277.44

0.47 0.93 2.09 4.09 8.77 13.35 31.01 49.32 87.16 177.32 320.19 517.21 1056.75 1911.78 3058.84 3954.59 5699.16

0.51 0.99 2.24 4.38 9.39 14.31 33.22 52.84 93.38 189.98 343.04 554.13 1132.18 2048.23 3277.16 4236.83 6105.92

0.54 1.06 2.38 4.66 9.99 15.21 35.33 56.19 99.31 202.03 364.80 589.28 1203.99 2178.15 3485.04 4505.59 6493.24

0.57 1.12 2.51 4.92 10.54 16.06 37.29 59.31 104.82 213.24 385.05 621.99 1270.82 2299.05 3678.47 4755.67 6853.65

Discharge Lines ( t = 1°F,  p = 3.55 psi) Saturated Suction Temperature, °F –60 –40 –20 0 20 40 Corresponding  p, psi/100 ft 3.55 3.55 3.55 3.55 3.55 3.55

1.3 1.9 4.3 2.1 3.8 8.5 3.9 8.6 19.2 6.5 16.9 37.5 11.6 36.3 80.3 16.0 55.3 122.3 30.4 128.4 283.5 43.3 204.7 450.9 66.9 361.6 796.8 115.3 735.6 1623.0 181.1 1328.2 2927.2 261.7 2148.0 4728.3 453.2 4394.4 9674.1 714.4 7938.5 17,477.4 1024.6 12,681.8 27,963.7 1249.2 16,419.6 36,152.5 1654.7 23,662.2 52,101.2

Velocity  t = 1°F t = 5°F Drop Drop = 100 fpm  p = 3.6 p = 17.4


Table 9.15 Suction, Discharge, and Liquid Line Capacities in Tons for Refrigerant 404A (Single- or High-Stage Applications) [2010R, Ch 1, Tbl 6] (Continued)



137

further reprodu

1/2 5/8 3/4 7/8 1 1/8 1 3/8 1 5/8 2 1/8 2 5/8 3 1/8 3 5/8 4 1/8 5 1/8 6 1/8 8 1/8

Type L Copper, OD

Line Size

Suction Lines ( t = 2°F) Saturated Suction Temperature, °F –40 –20 0 20

Corresponding p, psi/100 ft 1.01 1.46 2.02 2.71 0.09 0.15 0.24 0.37 0.17 0.28 0.45 0.69 0.28 0.48 0.77 1.17 0.44 0.74 1.18 1.81 0.90 1.51 2.40 3.66 1.57 2.63 4.18 6.35 2.48 4.17 6.61 10.04 5.17 8.65 13.70 20.76 9.14 15.27 24.19 36.62 14.61 24.40 38.55 58.29 21.75 36.22 57.15 86.47 30.66 51.13 80.55 121.93 54.88 91.25 143.93 217.14 88.20 146.87 230.77 348.36 182.97 303.62 477.80 720.09

–60

0.67 0.05 0.09 0.16 0.25 0.50 0.88 1.39 2.91 5.15 8.24 12.27 17.34 31.09 49.99 103.91

p = 17.8 5.96 11.13 18.45 29.14 58.74 102.09 161.04 331.97 584.28 929.27 1377.19 1935.27 3449.44 5526.55 11,383.18

t = 5°F Drop


40 Velocity t = 1°F Drop Corresponding p, psi/100 ft = 100 fpm p = 3.65 3.6 3.65 3.65 3.65 3.65 3.65 3.65 0.55 0.55 0.60 0.65 0.70 0.75 0.79 1.3 2.5 1.02 1.04 1.13 1.22 1.31 1.40 1.48 2.0 4.7 1.74 1.76 1.92 2.08 2.24 2.38 2.52 3.0 7.9 2.68 2.72 2.97 3.22 3.45 3.68 3.89 4.2 12.5 5.41 5.48 5.99 6.49 6.96 7.41 7.84 7.2 25.2 9.41 9.54 10.42 11.28 12.11 12.90 13.63 11.0 44.0 14.84 15.04 16.43 17.79 19.09 20.34 21.50 15.6 69.5 30.66 31.03 33.90 36.70 39.40 41.96 44.36 27.1 144.0 54.04 54.69 59.74 64.68 69.43 73.96 78.18 41.8 254.3 85.90 86.95 94.98 102.84 110.39 117.58 124.29 59.6 405.2 127.52 129.07 140.99 152.66 163.87 174.54 184.50 80.6 601.0 179.33 181.70 198.48 214.91 230.69 245.71 259.74 104.8 847.0 319.89 323.48 353.35 382.60 410.70 437.44 462.40 163.3 1513.6 512.29 518.62 566.52 613.40 658.45 701.32 741.34 234.8 2427.4 1057.14 1070.49 1169.35 1266.13 1359.11 1447.60 1530.21 410.1 5019.4 40

Discharge Lines ( t = 1°F,  p = 3.65 psi) Saturated Suction Temperature, °F –60 –40 –20 0 20


Refrigerants



138

further reprodu

Steel IPS SCH 3/8 80 1/2 80 3/4 80 1 80 1 1/4 80 1 1/2 80 2 40 2 1/2 40 3 40 4 40 5 40 6 40 8 40 10 40 12 IDb 14 30 16 30

Type L Copper, OD

0.04 0.08 0.18 0.35 0.76 1.16 2.70 4.31 7.63 15.57 28.10 45.48 93.13 168.64 269.75 349.22 503.20

0.67

–60

0.07 0.14 0.31 0.61 1.32 2.01 4.68 7.45 13.19 26.88 48.52 78.45 160.66 290.60 464.87 601.87 866.37

3.6

40

0.12 0.18 0.27 0.39 0.23 0.35 0.53 0.77 0.51 0.80 1.20 1.74 1.01 1.57 2.34 3.41 2.16 3.36 5.02 7.32 3.29 5.12 7.65 11.15 7.65 11.89 17.76 25.88 12.18 18.93 28.24 41.17 21.54 33.45 49.90 72.75 43.92 68.12 101.75 148.00 79.19 122.99 183.27 266.91 128.06 198.91 296.40 431.69 261.94 406.93 606.38 882.01 473.82 735.12 1095.44 1595.65 758.01 1174.36 1752.56 2553.03 979.92 1520.49 2269.19 3300.65 1414.32 2191.17 3265.09 4756.74

Suction Lines ( t = 2°F) Saturated Suction Temperature, °F –40 –20 0 20 Corresponding p, psi/100 ft 1.01 1.46 2.02 2.71

Refrigerants

Line Size

0.40 0.78 1.76 3.45 7.39 11.26 26.15 41.59 73.50 149.53 270.00 436.14 891.10 1612.10 2579.36 3334.69 4805.79

0.43 0.86 1.93 3.77 8.08 12.30 28.56 45.43 80.29 163.33 294.93 476.41 973.39 1760.97 2817.55 3642.64 5249.60

0.47 0.93 2.09 4.08 8.74 13.32 30.93 49.19 86.93 176.85 319.34 515.85 1053.96 1906.72 3050.75 3944.13 5684.09

0.51 0.99 2.24 4.38 9.39 14.30 33.20 52.80 93.32 189.84 342.79 553.73 1131.36 2046.75 3274.79 4233.77 6101.51

0.54 1.06 2.39 4.67 10.00 15.23 35.36 56.24 99.39 202.20 365.11 589.78 1205.02 2180.00 3488.00 4509.42 6498.76

0.57 1.12 2.52 4.94 10.57 16.10 37.38 59.45 105.06 213.74 385.94 623.44 1273.79 2304.41 3687.06 4766.76 6869.63

Discharge Lines ( t = 1°F,  p = 3.65 psi) Saturated Suction Temperature, °F –60 –40 –20 0 20 40 Corresponding p, psi/100 ft 3.65 3.65 3.65 3.65 3.65 3.65

1.2 2.1 3.8 6.3 11.2 15.5 29.4 41.9 64.6 111.4 174.9 252.8 437.7 690.0 989.6 1206.5 1598.2

1.9 3.7 8.4 16.4 35.2 53.8 124.8 198.9 351.5 714.9 1290.8 2087.5 4270.8 7715.1 12,324.9 15,957.5 22,996.2

4.2 8.3 18.7 36.6 78.4 119.4 276.7 440.6 777.9 1586.3 2857.5 4622.0 9443.9 17,086.7 27,298.3 35,292.2 50,861.5

Velocity t = 1°F t = 5°F Drop Drop = 100 fpm p = 3.65 p = 17.8





139

further reprodu

0.84

0.10 0.18 0.31 0.48 0.98 1.72 2.73 5.69 10.09 16.15 24.06 33.98 60.95 98.05 203.77

1/2 5/8 3/4 7/8 1 1/8 1 3/8 1 5/8 2 1/8 2 5/8 3 1/8 3 5/8 4 1/8 5 1/8 6 1/8 8 1/8

–60

Type L Copper, OD

Line Size

0.17 0.31 0.53 0.83 1.69 2.95 4.67 9.71 17.17 27.44 40.84 57.58 103.03 166.00 344.31

1.27

0.27 0.51 0.87 1.35 2.74 4.78 7.56 15.71 27.74 44.24 65.81 92.66 165.73 266.14 551.73

1.85 0.42 0.79 1.35 2.08 4.22 7.34 11.61 24.05 42.45 67.77 100.50 141.61 253.05 405.75 840.04

2.57

4.5

40

4.75

–60

4.75 1.22 2.29 3.88 5.99 12.09 21.00 33.16 68.44 120.41 191.80 284.19 400.07 712.88 1141.87 2356.89

4.75 1.26 2.36 4.02 6.19 12.50 21.72 34.30 70.78 124.53 198.36 293.90 413.75 737.26 1180.91 2437.49

4.75 1.30 2.43 4.14 6.38 12.88 22.37 35.33 72.90 128.25 204.29 302.70 426.13 759.31 1216.24 2510.41

4.75

Discharge Lines (t = 1°F, p = 4.75 psi) Saturated Suction Temperature, °F –40 –20 0 20 Corresponding p, psi/100 ft

0.62 0.89 1.13 1.17 1.17 1.67 2.11 2.20 2.00 2.84 3.59 3.74 3.08 4.39 5.53 5.76 6.23 8.86 11.16 11.64 10.85 15.41 19.39 20.21 17.14 24.28 30.63 31.92 35.45 50.19 63.20 65.88 62.53 88.43 111.20 115.90 99.53 140.83 177.12 184.62 147.66 208.65 262.44 273.54 208.22 293.70 369.45 385.08 370.82 523.21 658.32 686.18 594.85 839.82 1054.47 1099.10 1229.69 1733.02 2176.50 2268.62

3.46

Suction Lines (t = 2°F) Saturated Suction Temperature, °F –40 –20 0 20 Corresponding p, psi/100 ft

1.33 2.49 4.23 6.52 13.17 22.88 36.14 74.57 131.20 208.98 309.64 435.90 776.72 1244.13 2567.98

4.75

40

2.0 3.2 4.7 6.7 11.4 17.4 24.6 42.8 66.0 94.2 127.4 165.7 258.2 371.1 648.3

Velocity = 100 fpm

p = p = 23.3 4.75 4.6 10.81 8.6 20.24 14.3 33.53 22.6 52.92 45.8 106.59 79.7 185.04 125.9 291.48 260.7 601.13 459.7 1056.39 733.0 1680.52 1087.5 2491.00 1530.2 3500.91 2729.8 6228.40 4383.7 9980.43 9049.5 20,561.73

t = 1°F t = 5°F Drop Drop



Refrigerants



140

further reprodu

0.84

0.08 0.16 0.35 0.69 1.49 2.28 5.30 8.46 14.98 30.58 55.19 89.34 182.90 331.22 529.89 685.86 988.28

Steel IPS SCH 3/8 80 1/2 80 3/4 80 1 80 1 1/4 80 1 1/2 80 2 40 2 1/2 40 3 40 4 40 5 40 6 40 8 40 10 40 12 IDb 14 30 16 30

–60

Type L Copper, OD

1.85

2.57

3.46

0.13 0.21 0.32 0.46 0.26 0.41 0.62 0.91 0.59 0.93 1.41 2.04 1.15 1.83 2.75 4.00 2.48 3.92 5.90 8.58 3.79 5.98 9.01 13.06 8.80 13.89 20.91 30.32 14.02 22.13 33.29 48.23 24.81 39.10 58.81 85.22 50.56 79.68 119.77 173.76 91.27 143.84 216.23 312.97 147.57 232.61 349.71 506.16 301.82 475.80 715.45 1035.51 546.64 860.67 1292.44 1870.67 873.19 1376.89 2064.68 2992.85 1130.48 1779.99 2673.23 3875.08 1628.96 2569.05 3852.37 5575.79

1.27

Suction Lines (t = 2°F) Saturated Suction Temperature, °F –40 –20 0 20 Corresponding p, psi/100 ft

Refrigerants

Line Size

0.65 1.27 2.86 5.59 12.00 18.27 42.43 67.48 119.26 242.63 437.56 707.69 1445.92 2615.83 4185.32 5410.92 7797.98

4.5

40

0.81 1.59 3.59 7.02 15.03 22.89 53.16 84.56 149.44 304.02 548.97 886.76 1811.80 3277.74 5244.38 6780.14 9771.20

4.75

–60

0.84 1.66 3.74 7.32 15.67 23.86 55.41 88.14 155.76 316.88 572.20 924.29 1888.48 3416.46 5466.33 7067.08 10,184.73

4.75

0.88 1.73 3.88 7.60 16.28 24.79 57.57 91.57 161.82 329.21 594.46 960.25 1961.96 3549.40 5679.03 7342.06 10,581.02

4.75

0.91 1.78 4.02 7.86 16.83 25.64 59.54 94.70 167.36 340.47 614.79 993.09 2029.05 3670.77 5873.23 7593.13 10,942.85

4.75

0.93 1.84 4.14 8.10 17.34 26.41 61.32 97.53 172.37 350.66 633.19 1022.80 2089.76 3780.59 6048.94 7820.29 11,270.23

4.75

Discharge Lines (t = 1°F, p = 4.75 psi) Saturated Suction Temperature, °F –40 –20 0 20 Corresponding p, psi/100 ft

0.95 1.88 4.23 8.28 17.74 27.01 62.73 99.77 176.32 358.70 647.71 1046.26 2137.68 3867.29 6187.65 7999.63 11,528.68

4.75

40

1.9 3.2 6.0 10.0 17.7 24.4 46.4 66.2 102.2 176.1 276.5 399.6 692.0 1090.7 1564.3 1907.2 2526.4

Velocity = 100 fpm

3.4 6.7 15.1 29.5 63.3 96.6 224.2 356.5 630.0 1284.6 2313.7 3741.9 7655.3 13,829.2 22,125.4 28,647.5 41,220.5

p = 4.75

7.6 15.0 33.6 65.8 140.9 214.7 498.0 793.0 1398.4 2851.7 5137.0 8308.9 16,977.6 30,716.4 49,074.9 63,445.8 91,435.1

p = 23.3

t = 1°F t = 5°F Drop Drop





141

further reprodu

1/2 5/8 3/4 7/8 1 1/8 1 3/8 1 5/8 2 1/8 2 5/8 3 1/8 3 5/8 4 1/8 5 1/8 6 1/8 8 1/8

Type L Copper, OD

Line Size

Suction Lines (t = 2°F) Saturated Suction Temperature, °F –40 –20 0 20

Corresponding p, psi/100 ft 0.7 1.06 1.55 2.16 0.08 0.14 0.23 0.36 0.15 0.26 0.43 0.68 0.26 0.45 0.74 1.16 0.40 0.70 1.15 1.79 0.82 1.42 2.33 3.63 1.43 2.48 4.07 6.33 2.27 3.93 6.44 10.00 4.74 8.18 13.37 20.72 8.42 14.49 23.64 36.62 13.47 23.15 37.76 58.34 20.08 34.44 56.15 86.64 28.37 48.62 79.21 122.10 50.85 86.97 141.60 218.05 81.91 140.04 227.86 350.42 170.14 290.93 471.55 725.11

–60

0.435 0.04 0.08 0.14 0.21 0.44 0.77 1.23 2.56 4.55 7.30 10.90 15.42 27.70 44.70 92.98

–60

p = 16.9 8.90 16.68 27.66 43.73 88.21 153.45 241.93 499.23 879.85 1401.50 2076.59 2923.40 5209.13 8344.10 17,220.64

t = 5°F Drop


40 Velocity t = 1°F Drop Corresponding p, psi/100 ft = 100 fpm p = 3.5 2.92 3.3 3.3 3.3 3.3 3.3 3.3 0.54 0.71 0.75 0.78 0.82 0.86 0.89 2.1 3.8 1.02 1.33 1.40 1.47 1.54 1.61 1.67 3.4 7.1 1.74 2.26 2.38 2.50 2.62 2.73 2.84 4.9 11.8 2.68 3.48 3.67 3.86 4.05 4.22 4.38 6.9 18.7 5.42 7.05 7.43 7.82 8.19 8.53 8.86 11.8 37.9 9.45 12.25 12.92 13.59 14.23 14.83 15.40 18.0 66.2 14.93 19.33 20.39 21.44 22.46 23.40 24.30 25.5 104.7 30.90 39.99 42.17 44.35 46.45 48.40 50.27 44.4 217.1 54.50 70.56 74.41 78.25 81.96 85.40 88.70 68.5 383.7 86.88 112.34 118.47 124.59 130.50 135.97 141.22 97.7 611.3 128.89 166.39 175.47 184.54 193.29 201.39 209.17 132.2 907.9 181.34 234.63 247.42 260.22 272.56 283.98 294.95 171.8 1281.5 323.50 417.91 440.69 463.48 485.46 505.80 525.33 267.8 2288.8 519.62 670.58 707.15 743.71 778.97 811.62 842.96 385.0 3676.9 1072.54 1383.29 1458.72 1534.15 1606.88 1674.23 1738.88 672.4 7599.4 40

Discharge Lines (t = 1°F, p = 3.3 psi) Saturated Suction Temperature, °F –40 –20 0 20

Table 9.18 Suction, Discharge, and Liquid Line Capacities in Tons for Refrigerant 407C (Single- or High-Stage Applications) [2010R, Ch 1, Tbl 9]

Refrigerants



142

further reprodu

Steel IPS SCH 3/8 80 1/2 80 3/4 80 1 80 1 1/4 80 1 1/2 80 2 40 2 1/2 40 3 40 4 40 5 40 6 40 8 40 10 40 12 IDb 14 30 16 30

Type L Copper, OD

0.04 0.07 0.16 0.32 0.69 1.06 2.49 3.97 7.04 14.38 26.00 42.13 86.32 156.54 250.23 324.38 468.29

0.435

–60

0.07 0.13 0.30 0.58 1.25 1.91 4.46 7.11 12.59 25.70 46.36 75.15 153.84 278.57 445.65 576.93 831.27

2.92

40

0.11 0.18 0.27 0.40 0.22 0.35 0.54 0.79 0.50 0.80 1.22 1.79 0.98 1.57 2.38 3.50 2.10 3.37 5.12 7.50 3.21 5.13 7.79 11.44 7.47 11.93 18.13 26.57 11.90 19.01 28.83 42.25 21.05 33.59 50.94 74.66 42.97 68.47 103.84 152.24 77.55 123.61 187.25 274.21 125.49 199.88 302.82 443.47 256.66 408.86 619.47 907.26 464.86 739.58 1120.60 1638.95 742.54 1183.19 1790.17 2622.17 961.33 1529.58 2317.81 3395.13 1385.24 2204.17 3340.17 4885.19

Suction Lines (t = 2°F) Saturated Suction Temperature, °F –40 –20 0 20 Corresponding p, psi/100 ft 0.7 1.06 1.55 2.16

Refrigerants

Line Size

0.52 1.02 2.29 4.50 9.63 14.66 34.04 54.25 95.76 195.04 351.31 568.16 1162.36 2102.83 3359.45 4349.77 6258.81

3.3

–60

0.55 1.07 2.42 4.74 10.15 15.46 35.89 57.21 100.99 205.68 370.46 599.14 1225.74 2217.49 3542.64 4586.95 6600.09

0.57 1.13 2.54 4.99 10.68 16.26 37.75 60.16 106.21 216.31 389.62 630.12 1289.12 2332.15 3725.82 4824.14 6941.37

0.60 1.18 2.66 5.22 11.18 17.03 39.54 63.02 111.24 226.57 408.09 659.99 1350.24 2442.72 3902.46 5052.85 7270.46

0.63 1.23 2.78 5.44 11.65 17.74 41.20 65.66 115.90 236.06 425.19 687.65 1406.83 2545.10 4066.02 5264.62 7575.17

Discharge Lines (t = 1°F, p = 3.3 psi) Saturated Suction Temperature, °F –40 –20 0 20 Corresponding p, psi/100 ft 3.3 3.3 3.3 3.3

0.65 1.28 2.88 5.65 12.10 18.43 42.79 68.19 120.38 245.18 441.61 714.21 1461.15 2643.38 4223.03 5467.92 7867.69

3.3

40

2.0 3.4 6.2 10.3 18.4 25.4 48.1 68.6 106.0 182.6 286.8 414.5 717.7 1131.3 1622.5 1978.2 2620.4

2.9 5.7 12.8 25.1 53.7 82.0 190.3 303.2 535.7 1092.0 1969.0 3184.3 6514.5 11,784.6 18,826.0 24,374.8 35,126.4

Velocity t = 1°F Drop = 100 fpm p = 3.5

6.4 12.6 28.4 55.6 118.9 181.1 420.6 669.0 1182.3 2405.3 4343.2 7015.7 14,334.3 25,932.3 41,491.5 53,641.7 77,305.8

p = 16.9

t = 5°F Drop


Table 9.18 Suction, Discharge, and Liquid Line Capacities in Tons for Refrigerant 407C (Single- or High-Stage Applications) [2010R, Ch 1, Tbl 9] (Continued)



143

further reprodu

IPS 1/2 3/4 1 1 1/4 1 1/2 2

1/2 5/8 7/8 1 1/8 1 3/8 1 5/8 2 1/8 2 5/8 3 1/8 3 5/8 4 1/8 Steel

SCH 40 40 40 40 40 40

Type L Copper, OD

Line Size

0.58 1.2 2.3 4.8 7.2 13.9

0.85 1.8 3.4 7.0 10.5 20.2

1.2 2.5 4.8 9.9 14.8 28.5

0.79 — — 0.52 1.1 1.9 3.0 6.2 10.9 17.5 26.0 36.8

0.38 0.8 1.5 3.2 4.7 9.1

2.91 0.6 1.1 2.9 5.8 10.1 16.0 33.1 58.3 92.9 137.8 194.3

Corresponding  p, psi/100 ft 1.15 1.6 2.22 — — 0.40 0.32 0.51 0.76 0.86 1.3 2.0 1.7 2.7 4.0 3.1 4.7 7.0 4.8 7.5 11.1 10.0 15.6 23.1 17.8 27.5 40.8 28.4 44.0 65.0 42.3 65.4 96.6 59.6 92.2 136.3

–40

— 0.50 0.95 2.0 3.0 5.7

40

Suction Lines ( t = 2°F) Saturated Suction Temperature, °F –20 0 20

1.5 3.3 6.1 12.6 19.0 36.6

–40 0.75 1.4 3.7 7.5 13.1 20.7 42.8 75.4 120.2 178.4 251.1

1.7 3.7 6.9 14.3 21.5 41.4

40 0.85 1.6 4.2 8.5 14.8 23.4 48.5 85.4 136.2 202.1 284.4

Saturated Suction Temperature, °F

Discharge Lines ( t = 1°F,  p = 3.05 psi)

IPS 1/2 3/4 1 1 1/4 1 1/2 2

1/2 5/8 7/8 1 1/8 1 3/8 1 5/8 2 1/8 2 5/8 3 1/8 3 5/8 4 1/8 Steel SCH 80 80 80 80 80 40

Type L Copper, OD

Line Size

3.8 6.9 11.5 20.6 28.3 53.8

2.3 3.7 7.8 13.2 20.2 28.5 49.6 76.5 109.2 147.8 192.1

Vel. = 100 fpm

5.7 12.8 25.2 54.1 82.6 192.0

p = 3.05 3.6 6.7 18.2 37.0 64.7 102.5 213.0 376.9 601.5 895.7 1263.2

t = 1°F

Liquid Lines See notes a and b

Table 9.19 Suction, Discharge, and Liquid Line Capacities in Tons for Refrigerant 22 (Single- or High-Stage Applications) [2010R, Ch 1, Tbl 3]

Refrigerants



144

further reprodu

0.79

–40

Suction Lines ( t = 2°F) Saturated Suction Temperature, °F –20 0 20 Corresponding  p, psi/100 ft 1.15 1.6 2.22 2.91

40

Sizing shown is recommended where any gas generated in receiver must return up condensate line to condenser without restricting condensate flow. Water-cooled condensers, where receiver ambient temperature may be higher than refrigerant condensing temperature, fall into this category.

 Actual L e  Actual capacity 1.8  -----------------------  -------------------------------------  Table L e  Table capacity

Refrigerants

a

t = Table t

3. Saturation temperature t for other capacities and equivalent lengths Le

IPS SCH 2 1/2 40 9.2 14.6 22.1 32.2 45.4 3 40 16.2 25.7 39.0 56.8 80.1 4 40 33.1 52.5 79.5 115.9 163.2 Notes: 1. Table capacities are in tons of refrigeration. p = pressure drop from line friction, psi per 100 ft of equivalent line length t = corresponding change in saturation temperature, °F per 100 ft 2. Line capacity for other saturation temperatures t and equivalent lengths Le 0.55  Table L e Actual t Line capacity = Table capacity  -----------------------  -----------------------  Actual L e Table t 

Steel

Type L Copper, OD

Line Size

40 Steel

Type L Copper, OD

Line Size Vel. = 100 fpm

p = 3.05

t = 1°F


b

1.11 1.07 1.03 0.97 0.90 0.86 0.80

80 90 100 110 120 130 140

0.79 0.88 0.95 1.04 1.10 1.18 1.26

Discharge Line

Line pressure drop p is conservative; if subcooling is substantial or line is short, a smaller size line may be used. Applications with very little subcooling or very long lines may require a larger line.

Suction Line

Condensing Temperature, °F

IPS SCH 58.1 65.9 2 1/2 40 76.7 305.8 102.8 116.4 3 40 118.5 540.3 209.5 237.3 4 40 204.2 1101.2 4. Values based on 105°F condensing temperature. Multiply table capacities by the following factors for other condensing temperatures.

–40


Discharge Lines ( t = 1°F,  p = 3.05 psi)

Table 9.19 Suction, Discharge, and Liquid Line Capacities in Tons for Refrigerant 22 (Single- or High-Stage Applications) [2010R, Ch 1, Tbl 3] (Continued)



145

further reprodu

IPS 1/2 3/4 1 1 1/4

1/2 5/8 7/8 1 1/8 1 3/8 1 5/8 2 1/8 2 5/8 3 1/8 3 5/8 4 1/8 5 1/8 6 1/8 Steel

SCH 80 80 80 40

Type L Copper, OD

Line Size

Table 9.20

0.35 0.79 1.56 4.09

0.43 0.98 1.92 5.03

0.53 1.19 2.33 6.12

1.00 0.14 0.27 0.71 1.45 2.53 4.02 8.34 14.80 23.70 35.10 49.60 88.90 143.00

0.28 0.64 1.25 3.30

1.93 0.35 0.66 1.75 3.54 6.17 9.77 20.20 35.80 57.10 84.80 119.43 213.00 342.00

Corresponding p, psi/100 ft 1.19 1.41 1.66 0.18 0.23 0.29 0.34 0.43 0.54 0.91 1.14 1.42 1.84 2.32 2.88 3.22 4.04 5.02 5.10 6.39 7.94 10.60 13.30 16.50 18.80 23.50 29.10 30.00 37.50 46.40 44.60 55.80 69.10 62.90 78.70 97.40 113.00 141.00 174.00 181.00 226.00 280.00

0

0.22 0.51 1.00 2.62

40

Suction Lines (t = 2°F) Saturated Suction Temperature, °F 10 20 30

0.79 1.79 3.51 9.20

0 0.54 1.01 2.67 5.40 9.42 14.90 30.80 54.40 86.70 129.00 181.00 323.00 518.00

0.84 1.88 3.69 9.68

20 0.57 1.07 2.81 5.68 9.91 15.70 32.40 57.20 91.20 135.00 191.00 340.00 545.00

0.88 1.97 3.86 10.10

40 0.59 1.12 2.94 5.95 10.40 16.40 34.00 59.90 95.50 142.00 200.00 356.00 571.00


Discharge Lines (t = 1°F, p = 2.2 psi/100 ft)

IPS 1/2 3/4 1 1 1/4

1/2 5/8 7/8 1 1/8 1 3/8 1 5/8 2 1/8 2 5/8 3 1/8 3 5/8 4 1/8 — — Steel SCH 80 80 80 80

Type L Copper, OD

Line Size

3.43 6.34 10.50 18.80

4.38 9.91 19.50 41.80

Velocity = t = 1°F 100 fpm p = 2.2 2.13 2.79 3.42 5.27 7.09 14.00 12.10 28.40 18.40 50.00 26.10 78.60 45.30 163.00 69.90 290.00 100.00 462.00 135.00 688.00 175.00 971.00 — — — —


Suction, Discharge, and Liquid Line Capacities in Tons for Refrigerant 134a (Single- or High-Stage Applications) [2010R, Ch 1, Tbl 5]

Refrigerants



146

further reprodu

e

1.00

0

Suction Lines (t = 2°F) Saturated Suction Temperature, °F 10 20 30 Corresponding p, psi/100 ft 1.19 1.41 1.66 1.93

40

Sizing shown is recommended where any gas generated in receiver must return up condensate line to the condenser without restricting condensate flow. Water-cooled condensers, where receiver ambient temperature may be higher than refrigerant condensing temperature, fall into this category.

Refrigerants

a

20

40

Type L Copper, OD

Line Size

Velocity = t = 1°F 100 fpm p = 2.2


b

1.158 1.095 1.032 0.968 0.902 0.834

80 90 100 110 120 130

0.804 0.882 0.961 1.026 1.078 1.156

Discharge Line

Line pressure drop p is conservative; if subcooling is substantial or line is short, a smaller size line may be used. Applications with very little subcooling or very long lines may require a larger line.

Suction Line

Condensing Temperature, °F

Steel IPS SCH 13.80 14.50 15.20 1 1/2 80 25.90 63.70 26.60 28.00 29.30 2 40 49.20 148.00 42.40 44.60 46.70 2 1/2 40 70.10 236.00 75.00 78.80 82.50 3 40 108.00 419.00 153.00 160.00 168.00 4 40 187.00 853.00 4. Values based on 105°F condensing temperature. Multiply table capacities by the following factors for other condensing temperatures.

0


Discharge Lines (t = 1°F, p = 2.2 psi/100 ft)

Suction, Discharge, and Liquid Line Capacities in Tons for Refrigerant 134a (Single- or High-Stage Applications) [2010R, Ch 1, Tbl 5] (Continued)

IPS SCH 1 1/2 40 3.94 4.95 6.14 7.54 9.18 2 40 7.60 9.56 11.90 14.60 17.70 2 1/2 40 12.10 15.20 18.90 23.10 28.20 3 40 21.40 26.90 33.40 41.00 49.80 4 40 43.80 54.90 68.00 83.50 101.60 Notes: 1. Table capacities are in tons of refrigeration. p = pressure drop from line friction, psi per 100 ft of equivalent line length t = corresponding change in saturation temperature, °F per 100 ft 2. Line capacity for other saturation temperatures t and equivalent lengths Le 0.55  Table L e Actual t Line capacity = Table capacity  -----------------------  -----------------------  Actual L e Table t  3. Saturation temperature t for other capacities and equivalent lengths Le  Actual L e  Actual capacity 1.8 - ------------------------------------t = Table t  --------------------- Table L   Table capacity 

Steel

Type L Copper, OD

Line Size

Table 9.20



147

further reprodu

22

Refrigerant

40.0

20.0

0.0

–20.0

Saturate d Suction Temp., °F –40.0

0.165 0.165

70.0 90.0

0.296 0.296

0.119 0.117 0.118 0.156 0.153 0.154 0.199 0.194 0.195 0.244 0.242 0.242 0.300

0.233

0.146

0.067 0.065 0.066 0.087 0.085 0.086 0.111 0.108 0.109 0.136 0.135 0.135 0.167

5/8

1/2

–30.0 –10.0 10.0 –10.0 10.0 30.0 10.0 30.0 50.0 30.0 50.0 70.0 50.0

Suction Gas Temp., °F

0.488 0.488

0.197 0.194 0.195 0.258 0.253 0.254 0.328 0.320 0.322 0.403 0.399 0.400 0.495

0.348

3/4

0.737 0.738

0.298 0.292 0.295 0.389 0.362 0.383 0.496 0.484 0.486 0.608 0.603 0.605 0.748

0.484

7/8

1.44 1.44

0.580 0.570 0.575 0.758 0.744 0.747 0.986 0.942 0.946 1.18 1.17 1.18 1.46

0.825

1 1/8

2.43 2.43

0.981 0.963 0.972 1.28 1.26 1.26 1.63 1.59 1.60 2.00 1.99 1.99 2.46

1.256

3.75 3.76

1.52 1.49 1.50 1.98 1.95 1.95 2.53 2.46 2.47 3.10 3.07 3.08 3.81

1.780

Pipe OD, in. 1 3/8 1 5/8 Area, in2

7.49 7.50

3.03 2.97 3.00 3.96 3.88 3.90 5.04 4.92 4.94 6.18 6.13 6.15 7.60

3.094

2 1/8

12.9 12.9

5.20 5.11 5.15 6.80 6.67 6.69 8.66 8.45 8.48 10.6 10.5 10.6 13.1

4.770

2 5/8

20.1 20.1

8.12 7.97 8.04 10.6 10.4 10.4 13.5 13.2 13.2 16.6 16.4 16.5 20.4

6.812

3 1/8

29.3 29.3

11.8 11.6 11.7 15.5 15.2 15.2 19.7 19.2 19.3 24.2 24.0 24.0 29.7

9.213

3 5/8

Table 9.21 Minimum Refrigeration Capacity in Tons for Oil Entrainment up Suction Risers (Type L Copper Tubing) [2010R, Ch 1, Tbl 20]

Refrigerants


40.7 40.7

16.4 16.1 16.3 21.5 21.1 21.1 27.4 26.7 26.8 33.5 33.3 33.3 41.3

11.970

4 1/8


148

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40.0

30.0

20.0

10.0

Saturate d Suction Temp., °F 0.0

10.0 30.0 50.0 20.0 40.0 60.0 30.0 50.0 70.0 40.0 60.0 80.0 50.0 70.0 90.0

Suction Gas Temp., °F 0.161 0.135 0.130 0.182 0.152 0.147 0.205 0.172 0.166 0.207 0.193 0.187 0.232 0.212 0.206

0.233

0.146

0.089 0.075 0.072 0.101 0.084 0.081 0.113 0.095 0.092 0.115 0.107 0.103 0.128 0.117 0.114

5/8

1/2

Refrigerants

Notes: 1. Refrigeration capacity in tons is based on 90°F liquid temperature and superheat as indicated by listed temperature. For other liquid line temperatures, use correction factors in table at right. 2. Values computed using ISO 32 mineral oil for R-22. R-134a computed using ISO 32 ester-based oil.

134a

Refrigerant

22 134a

Refrigerant

0.259 0.218 0.209 0.294 0.246 0.237 0.331 0.277 0.268 0.335 0.311 0.301 0.374 0.342 0.332

0.348

3/4

50 1.17 1.26

0.400 0.336 0.323 0.453 0.379 0.366 0.510 0.427 0.413 0.517 0.480 0.465 0.577 0.528 0.512

0.484

7/8

60 1.14 1.20

0.78 0.66 0.63 0.88 0.74 0.71 0.99 0.83 0.81 1.01 0.94 0.91 1.12 1.03 1.00

0.825

1 1/8

70 1.10 1.13

1.32 1.11 1.07 1.49 1.25 1.21 1.68 1.41 1.36 1.70 1.58 1.53 1.90 1.74 1.69

1.256 4.06 3.42 3.28 4.61 3.86 3.73 5.19 4.34 4.20 5.25 4.88 4.72 5.87 5.37 5.21

3.094

2 1/8

7.0 5.9 5.6 7.9 6.6 6.4 8.9 7.5 7.2 9.0 8.4 8.1 10.1 9.2 8.9

4.770

2 5/8

Liquid Temperature, °F 80 100 110 1.06 0.98 0.94 1.07 0.94 0.87

2.03 1.71 1.64 2.31 1.93 1.87 2.60 2.17 2.10 2.63 2.44 2.37 2.94 2.69 2.61

1.780

Pipe OD, in. 1 3/8 1 5/8 Area, in2

120 0.89 0.80

10.9 9.2 8.8 12.4 10.3 10.0 13.9 11.6 11.3 14.1 13.1 12.7 15.7 14.4 14.0

6.812

3 1/8

130 0.85 0.74

15.9 13.4 12.8 18.0 15.1 14.6 20.3 17.0 16.4 20.5 19.1 18.5 22.9 21.0 20.4

9.213

3 5/8

Table 9.21 Minimum Refrigeration Capacity in Tons for Oil Entrainment up Suction Risers (Type L Copper Tubing) [2010R, Ch 1, Tbl 20] (Continued)


140 0.80 0.67

22.1 18.5 17.8 25.0 20.9 20.2 28.2 23.6 22.8 28.5 26.5 25.6 31.8 29.1 28.3

11.970

4 1/8


149

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80.0

22

120.0

110.0

100.0

90.0

Saturated Temp., °F

Refrigerant

110.0 140.0 170.0 120.0 150.0 180.0 130.0 160.0 190.0 140.0 170.0 200.0 150.0 180.0 210.0

Discharge Gas Temp., °F 5/8 0.233 0.421 0.399 0.385 0.433 0.406 0.387 0.442 0.414 0.394 0.451 0.421 0.399 0.460 0.428 0.404

1/2

0.146 0.235 0.223 0.215 0.242 0.226 0.216 0.247 0.231 0.220 0.251 0.235 0.222 0.257 0.239 0.225

0.348 0.695 0.659 0.635 0.716 0.671 0.540 0.730 0.884 0.650 0.744 0.693 0.658 0.760 0.707 0.666

3/4 0.484 1.05 0.996 0.960 1.06 1.01 0.956 1.10 1.03 0.982 1.12 1.05 0.994 1.15 1.07 1.01

7/8 0.825 2.03 1.94 1.87 2.11 1.97 1.88 2.15 2.01 1.91 2.19 2.05 1.94 2.24 2.08 1.96

1 1/8 1.256 3.46 3.28 3.16 3.56 3.34 3.18 3.83 3.40 3.24 3.70 3.46 3.28 3.78 3.51 3.31

1.780 5.35 5.07 4.89 5.50 5.16 4.92 5.62 5.26 3.00 5.73 3.35 5.06 5.85 5.44 5.12

Pipe OD, in. 1 3/8 1 5/8 Area, in2 3.094 10.7 10.1 9.76 11.0 10.3 9.82 11.2 10.5 9.96 11.4 10.7 10.1 11.7 10.8 10.2

2 1/8 4.770 18.3 17.4 16.8 18.9 17.7 16.9 19.3 18.0 17.2 19.6 18.3 17.4 20.0 18.6 17.6

2 5/8 6.812 28.6 27.1 26.2 29.5 27.6 26.3 30.1 28.2 26.8 30.6 28.6 27.1 31.3 29.1 27.4

3 1/8

9.213 41.8 39.6 38.2 43.0 40.3 38.4 43.9 41.1 39.1 44.7 41.8 39.5 45.7 42.4 40.0

3 5/8

Table 9.22 Minimum Refrigeration Capacity in Tons for Oil Entrainment up Hot-Gas Risers (Type L Copper Tubing) [2010R, Ch 1, Tbl 19]

Refrigerants


11.970 57.9 54.9 52.9 59.6 55.9 53.3 60.8 57.0 54.2 62.0 57.9 54.8 63.3 58.9 55.5

4 1/8


150

further reprodu

80.0

134a

110.0 140.0 170.0 120.0 150.0 180.0 130.0 160.0 190.0 140.0 170.0 200.0 150.0 180.0 210.0

Discharge Gas Temp., °F 5/8 0.233 0.360 0.331 0.318 0.364 0.333 0.320 0.372 0.340 0.326 0.378 0.346 0.331 0.383 0.351 0.334

1/2

0.146 0.199 0.183 0.176 0.201 0.184 0.177 0.206 0.188 0.180 0.209 0.191 0.183 0.212 0.194 0.184

Refrigerants

0.348 0.581 0.535 0.512 0.587 0.538 0.516 0.600 0.549 0.526 0.610 0.558 0.534 0.618 0.566 0.538

3/4 0.484 0.897 0.825 0.791 0.906 0.830 0.796 0.926 0.848 0.811 0.942 0.861 0.824 0.953 0.873 0.830

7/8 0.825 1.75 1.61 1.54 1.76 1.62 1.55 1.80 1.65 1.58 1.83 1.68 1.61 1.86 1.70 1.62

1 1/8 3.094 9.12 8.39 8.04 9.21 8.44 8.09 9.42 8.62 8.25 9.57 8.76 8.38 9.69 8.88 8.44

2 1/8

22 134a

Refrigerant

Pipe OD, in. 1 3/8 1 5/8 Area, in2 1.256 1.780 2.96 4.56 2.72 4.20 2.61 4.02 2.99 4.61 2.74 4.22 2.62 4.05 3.05 4.71 2.79 4.31 2.67 4.13 3.10 4.79 2.84 4.38 2.72 4.19 3.14 4.85 2.88 4.44 2.74 4.23

Notes: 1. Refrigeration capacity in tons based on saturated suction temperature of 20°F with 15°F superheat at indicated saturated condensing temperature with 15°F subcooling. For other saturated suction temperatures with 15°F superheat, use correction factors in the table at right. 2. Table computed using ISO 32 mineral oil for R-22, and ISO 32 ester-based oil for R-134a.

120.0

110.0

100.0

90.0

Saturated Temp., °F

Refrigerant 6.812 24.4 22.5 21.6 24.7 22.6 21.7 25.2 23.1 22.1 25.7 23.5 22.5 26.0 23.8 22.6

3 1/8 9.213 35.7 32.8 31.4 36.0 33.0 31.6 36.8 33.7 32.2 37.4 34.2 32.8 37.9 34.7 33.0

3 5/8

11.970 49.5 45.6 43.6 50.0 45.8 43.9 51.1 46.8 44.8 52.0 47.5 45.5 52.6 48.2 45.8

4 1/8

Saturated Suction Temperature, °F –40 –20 0 +40 0.92 0.95 0.97 1.02 — — 0.96 1.04

4.770 15.7 14.4 13.8 15.8 14.5 13.9 16.2 14.8 14.2 16.5 15.0 14.4 16.7 15.3 14.5

2 5/8

Table 9.22 Minimum Refrigeration Capacity in Tons for Oil Entrainment up Hot-Gas Risers (Type L Copper Tubing) [2010R, Ch 1, Tbl 19] (Continued)



151

further reprodu

t = Table t

 Actual L e  Actual capacity 1.8  -----------------------  -------------------------------------  Table L e  Table capacity

 Table L e Actual t Line capacity = Table capacity  -----------------------  -----------------------  Actual L e Table t  3. Saturation temperature t for other capacities and equivalent lengths Le

0.55

Suction Lines (t = 1°F) Saturated Suction Temperature, °F –20 0 20 p = 0.49 p = 0.73 p = 1.06 — — — — — — — — 2.6 2.1 3.4 5.2 5.6 8.9 13.6 8.4 13.4 20.5 16.2 26.0 39.6 25.9 41.5 63.2 46.1 73.5 111.9 94.2 150.1 228.7 170.4 271.1 412.4 276.4 439.2 667.5 566.8 901.1 1366.6 1027.2 1634.3 2474.5 1644.5 2612.4 3963.5

1.00

1.00

100 0.98 1.11 5. Discharge and liquid line capacities based on 20°F suction. Evaporator temperature is 0°F. The capacity is affected less than 3% when applied from –40 to +40°F extremes.

90

Discharge Steel Liquid Lines Lines Line Size –40 40 t = 1°F Velocity = p =2.0 psi IPS SCH IPS SCH p = 0.31 p = 1.46 p = 2.95 100 fpm t = 0.7°F 3/8 80 — — — 3/8 80 8.6 12.1 1/2 80 — — 3.1 1/2 80 14.2 24.0 3/4 80 — 3.8 7.1 3/4 80 26.3 54.2 1 80 — 7.6 13.9 1 80 43.8 106.4 1 1/4 40 3.2 19.9 36.5 1 1/4 80 78.1 228.6 1 1/2 40 4.9 29.9 54.8 1 1/2 80 107.5 349.2 2 40 9.5 57.8 105.7 2 40 204.2 811.4 2 1/2 40 15.3 92.1 168.5 2 1/2 40 291.1 1292.6 3 40 27.1 163.0 297.6 3 40 449.6 2287.8 4 40 55.7 333.0 606.2 4 40 774.7 4662.1 5 40 101.1 600.9 1095.2 5 40 — — 6 40 164.0 971.6 1771.2 6 40 — — 8 40 337.2 1989.4 3623.0 8 40 — — 10 40 611.6 3598.0 — 10 40 — — 12 ID* 981.6 5764.6 — 12 ID* — — Notes: 4. Values based on 90°F condensing temperature. Multiply table capacities by the 1. Table capacities are in tons of refrigeration. following factors for other condensing temperatures: p = pressure drop due to line friction, psi per 100 ft of equivalent line length Condensing Temperature, °F Suction Lines Discharge Lines t = corresponding change in saturation temperature, °F per 100 ft 70 1.05 0.78 2. Line capacity for other saturation temperatures t and equivalent lengths Le 80 1.02 0.89

Steel Line Size

Table 9.23 Suction, Discharge, and Liquid Line Capacities in Tons for Ammonia (Single- or High-Stage Applications) [2010R, Ch 2, Tbl 2]

Refrigerants



152

further reprodu

3:1 513 1175 1875 2700 4800 — — —

4:1 387 879 1407 2026 3600 — — —

5:1 308 703 1125 1620 2880 — — —

Pumped Liquid Overfeed Ratio

1544 3573 5683 10 150 — — — —

High-Pressure Liquid at 21 kPaa 106 176 324 570 1154 2089 3411 —

Hot-Gas Defrosta 791 1055 1759 3517 7034 — — —

Equalizer High Sideb

Thermosiphon Lubricant Cooling Lines Gravity Flowc Supply Return Vent 59 35 60 138 88 106 249 155 187 385 255 323 663 413 586 1041 649 1062 1504 938 1869 2600 1622 3400

Liquid Ammonia Line Capacities in Kilowatts [2010R, Ch 2, Tbl 3]

b

a

Refrigerants

Source: Wile (1977). Rating for hot-gas branch lines under 30 m with minimum inlet pressure of 724 kPa (gage), defrost pressure of 483 kPa (gage), and –29°C evaporators designed for a 5.6 K temperature differential. Line sizes based on experience using total system evaporator kilowatts. c From Frick Co. (1995). Values for line sizes above 100 mm are extrapolated.

40 50 65 80 100 125 150 200

Nominal Size, mm

Table 9.24



153

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Lubricants In Refrigerant Systems Oil in refrigerant compressors lubricates, acts as coolant, and seals the suction from the discharge side. Oil mixes well with hydrocarbon refrigerants at higher temperatures; miscibility is reduced as temperature lowers. Oil leaves the compressor and dissolves into the refrigerant in the condenser, and passes through the liquid line to the evaporator where it separates. In higher temperature systems, it returns by gravity or is dragged by the returning vapor. Low temperature halocarbon systems need an oil separator at the compressor discharge. Oil return up vertical piping requires significant refrigerant velocity. Lubricants are generally not miscible with ammonia and separate easily out of the liquid. Oil separators at the discharge of compressors are essential. Oil must be periodically or continuously removed and returned to the compressor. There is no ideal lubricant. For halocarbon refrigerants, there are mineral lubricants, both naphthenic and paraffinic, and synthetic lubricants, ester and glycol. Viscosity grades required vary with the temperature and the solubility of the refrigerant in the lubricant. Additives are used to enhance lubricant properties or impact new characteristics. They may be polar compounds, polymers, or compounds containing active elements such as sulfur or phosphorus. Lubricants should be dry; normally almost all hydrocarbon lubricants have a moisture content of about 30 ppm. Synthetic lubricants polyalkylene glycols (PAGs) are used commonly in automobile R-134a systems; polyalphaolefins (PAOs) are mainly used an immiscible oil in ammonia systems; polyol esters are used with HFC refrigerants in all types of compressors. Low pour point is essential for oils in ammonia systems. Table 9.25

Secondary Coolant Performance Comparisons [2010R, Ch 13, Tbl 1]

Secondary Coolant Propylene glycol Ethylene glycol Methanol Sodium chloride Calcium chloride Aqua ammonia Trichloroethylene d-Limonene Methylene chloride R-11

Concentration (by Weight), % 39 38 26 23 22 14 100 100 100 100

Freeze Point, °F –5.1 –6.9 –5.3 –5.1 –7.8 –7.0 –123 –142 –142 –168

gpm/tona 2.56 2.76 2.61 2.56 2.79 2.48 7.44 6.47 6.39 7.61

Pressure Heat Transfer Drop,b Coefficientc hi, psi Btu/h·ft2 ·°F 2.91 205 2.38 406 2.05 473 2.30 558 2.42 566 2.44 541 2.11 432 1.48 321 1.86 58 2.08 428

Refrigerants

a Based b

on inlet secondary coolant temperature at pump of 25°F. Based on one length of 16 ft tube with 1.06 in. ID and use of Moody Chart (1944) for an average velocity of 7 fps. Input/output losses equal one Vel. HD (V 2/2g) for 7 fps velocity. Evaluations are at a bulk temperature of 20°F and a temperature range of 10°F. c Based on curve fit equation for Kern’s (1950) adaptation of Sieder and Tate’s (1936) heat transfer equation using 16 ft tube for L/D = 181 and film temperature of 5°F lower than average bulk temperature with 7 fps velocity.

Table 9.26

Relative Pumping Energy Required* [2010R, Ch 13, Tbl 3]

Secondary Coolant Aqua ammonia Methanol Propylene glycol Ethylene glycol Sodium chloride Calcium chloride d-Limonene Methylene chloride Trichloroethylene Aqua ammonia Methanol R-11

Energy Factor 1.000 1.078 1.142 1.250 1.295 1.447 2.406 3.735 4.787 1.000 1.078 5.022

* Based on same pump pressure, refrigeration load, 20°F average temperature, 10°F range, and freezing point (for water-based secondary coolants) 20 to 23°F below lowest secondary coolant temperature.

154

further reprodu


10.

REFRIGERANT SAFETY

Figure 10.1 Refrigerant Safety Group Classification [Std 34-2010, Fig 1]

Refrigerant Safety

155

further reprodu

c

b

a

chlorodifluoromethane 2,2-dichloro-1,1,1-trifluoroethane 1,1,1,2-tetrafluoroethane 1-chloro-1,1-difluoroethane 1,1-difluoroethane propane ammonia carbon dioxide 2,3,3,3-tetrafluoro-1-propene

Chemical Namea,b CHClF2 CHCl2CF3 CH2FCF3 CH3CClF2 CH3CHF2 CH3CH2CH3 NH3 CO2 CF3CF=CH2

Chemical Formulaa Al B1 A1 A2 A2 A3 B2 A1 A2

Safety Group (ppm v/v) 59,000 9100 50,000 20,000 12,000 5300 320 40,000 16,000

Table 10.1 Refrigerant Data and Safety Classifications [Std 34-2010, Tbl 1, Abridged] RCLc (g/m3) 210 57 210 83 32 9.5 0.22 72 75

(lb/1000 ft3) 13 3.5 13 5.1 2.0 0.56 0.014 4.5 4.7

The chemical name and chemical formula are not part of this standard. Chemical names conform to IUPAC nomenclature14,15 except where shortened unambiguous names are used following ASHRAE Standard 34 convention. The preferred chemical name is followed by the popular name in parentheses. Data taken from J.M. Calm, “ARTI Refrigerant Database,” Air- Conditioning and Refrigeration Technology Institute (ARTI), Arlington, VA, July 2001; J.M. Calm, “Toxicity Data to Determine Refrigerant Concentration Limits,” Report DE/CE 23810-110, Air- Conditioning and Refrigeration Technology Institute (ARTI), Arlington, VA, September 2000; J.M. Calm, “The Toxicity of Refrigerants,” Proceedings of the 1996 International Refrigeration Conference, Purdue University, West Lafayette, IN, pp. 157–62, 1996; D.P. Wilson and R.G. Richard, “Determination of Refrigerant Lower Flammability Limits (LFLs) in Compliance with Proposed Addendum p to ANSI/ASHRAE Standard 34-1992 (1073-RP),” ASHRAE Transactions 2002, 108(2); D.W. Coombs, “HFC-32 Assessment of Anesthetic Potency in Mice by Inhalation,” Huntingdon Life Sciences Ltd., Huntingdon, Cambridgeshire, England, February 2004 and amendment February 2006; D.W. Coombs, “HFC-22 An Inhalation Study to Investigate the Cardiac Sensitization Potential in the Beagle Dog,” Huntingdon Life Sciences Ltd., Huntingdon, Cambridgeshire, England, August 2005; and other toxicity studies.

22 123 134a 142b 152a 290 717 744 1234yf

Refrigerant Number

Refrigerant Safety



156

further reprodu

Refrigerant Safety

R-125/143a/134a (44.0/52.0/4.0) R-32/125/134a (23.0/25.0/52.0) R-32/125 (50.0/50.0) R-125/143a (50.0/50.0)

Composition (Mass %) (±2.0/±1.0/±2.0) (±2.0/±2.0/±2.0) (+0.5, –1.5/+1.5, –0.5)

Composition Tolerances A1 A1 A1 A1

Safety Group (ppm v/v) 130,000 76,000 130,000 130,000

RCLa (g/m3) 500 270 390 520

Table 10.2 Data and Safety Classifications for Refrigerant Blends [Std 34-2010, Tbl 2, Abridged] (lb/1000 ft3) 31 17 25 32

Data taken from J.M. Calm, “ARTI Refrigerant Database,” Air- Conditioning and Refrigeration Technology Institute (ARTI), Arlington, VA, July 2001; J.M. Calm, “Toxicity Data to Determine Refrigerant Concentration Limits,” Report DE/CE 23810-110, Air- Conditioning and Refrigeration Technology Institute (ARTI), Arlington, VA, September 2000; J.M. Calm, “The Toxicity of Refrigerants,” Proceedings of the 1996 International Refrigeration Conference, Purdue University, West Lafayette, IN, pp. 157–62, 1996; D.P. Wilson and R.G. Richard, “Determination of Refrigerant Lower Flammability Limits (LFLs) in Compliance with Proposed Addendum p to ANSI/ASHRAE Standard 34-1992 (1073-RP),” ASHRAE Transactions 2002, 108(2); D.W. Coombs, “HFC-32 Assessment of Anesthetic Potency in Mice by Inhalation,” Huntingdon Life Sciences Ltd., Huntingdon, Cambridgeshire, England, February 2004 and amendment February 2006; D.W. Coombs, “HFC-22 An Inhalation Study to Investigate the Cardiac Sensitization Potential in the Beagle Dog,” Huntingdon Life Sciences Ltd., Huntingdon, Cambridgeshire, England, August 2005; and other toxicity studies. d R-507, R-508, and R-509 are allowed alternative designations for R-507A, R-508A, and R-509A due to a change in designations after assignment of R-500 through R-509. Corresponding changes were not made for R-500 through R-506. h At locations with altitudes higher than 4920 ft, the ODL and RCL shall be 69,100 ppm. j At locations with altitudes higher than 3300 ft but below or equal to 4920 ft, the ODL and RCL shall be 112,000 ppm, and at altitudes higher than 4920 ft, the ODL and RCL shall be 69,100 ppm.

a

404Aj 407Ch 410Aj 507Ad,j

Refrigerant Number



157

further reprodu


ASHRAE Standard 15-2010, Safety Standard for Refrigeration Systems (See complete standard for detailed guidance.) 7.

RESTRICTIONS ON REFRIGERANT USE

7.1 General. The occupancy, refrigerating system, and refrigerant safety classifications cited in this section shall be determined in accordance with Sections 4, 5, and 6, respectively. 7.2 Refrigerant Concentration Limits. The concentration of refrigerant in a complete discharge of each independent circuit of high-probability systems shall not exceed the amounts shown in Table 1 or 2 of ASHRAE Standard 34,1 except as provided in Sections 7.2.1 and 7.2.2 of this standard. The volume of occupied space shall be determined in accordance with Section 7.3. Exceptions: a. Listed equipment containing not more than 6.6 lb (3 kg) of refrigerant, regardless of its refrigerant safety classification, is exempt from Section 7.2 provided the equipment is installed in accordance with the listing and with the manufacturer’s installation instructions. b. Listed equipment for use in laboratories with more than 100 ft2 (9.3 m2) of space per person, regardless of the refrigerant safety classification, is exempt from Section 7.2 provided that the equipment is installed in accordance with the listing and the manufacturer’s installation instructions. 7.2.1 Institutional Occupancies. The amounts shown in Table 1 or 2 of ASHRAE Standard 341 shall be reduced by 50% for all areas of institutional occupancies. Also, the total of all Group A2, B2, A3, and B3 refrigerants shall not exceed 550 lb (250 kg) in the occupied areas and machinery rooms of institutional occupancies. 7.2.2 Industrial Occupancies and Refrigerated Rooms. Section 7.2 does not apply in industrial occupancies and refrigerated rooms where the following seven conditions are met: 1. The space(s) containing the machinery is (are) separated from other occupancies by tight construction with tight-fitting doors. 2. Access is restricted to authorized personnel. 3. The floor area per occupant is not less than 100 ft2 (9.3 m2).

4. 5. 6.

Refrigerant Safety

7.

Exception: The minimum floor area shall not apply where the space is provided with egress directly to the outdoors or into approved building exits. Refrigerant detectors are installed with the sensing location and alarm level as required in refrigerating machinery rooms in accordance with Section 8.11.2.1. Open flames and surfaces exceeding 800°F (426.7°C) are not permitted where any Group A2, B2, A3, or B3 refrigerant other than R-717 (ammonia) is used. All electrical equipment conforms to Class 1, Division 2, of NFPA 705 where the quantity of any Group A2, B2, A3, or B3 refrigerant other than R-717 (ammonia) in an independent circuit would exceed 25% of the lower flammability limit (LFL) upon release to the space based on the volume determined by Section 7.3. All refrigerant-containing parts in systems exceeding 100 hp (74.6 kW) compressor drive power, except evaporators used for refrigeration or dehumidification, condensers used for heating, control and pressure-relief valves for either, and connecting piping, are located either in a machinery room or outdoors.

7.3 Volume Calculations. The volume used to convert from refrigerant concentration limits to refrigerating system quantity limits for refrigerants in Section 7.2 shall be based on the volume of space to which refrigerant disperses in the event of a refrigerant leak. 7.3.1 Nonconnecting Spaces. Where a refrigerating system or a part thereof is located in one or more enclosed occupied spaces that do not connect through permanent openings or HVAC ducts, the volume of the smallest occupied space shall be used to determine the refrigerant quantity limit in the system. Where different stories and floor levels connect through an open atrium or mezzanine arrangement, the volume to be used in calculating the refrigerant quantity limit shall be determined by multiplying the floor area of the lowest space by 8.2 ft (2.5 m). 7.3.2 Ventilated Spaces. Where a refrigerating system or a part thereof is located within an air handler, in an air distribution duct system, or in an occupied space served by a mechanical ventilation system, the entire air distribution system shall be analyzed to determine the worst-case distribution of leaked refrigerant. The worst case or the smallest volume in which the leaked refrigerant disperses shall be used to determine the refrigerant quantity limit in the system, subject to the following criteria. 158

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7.3.2.1 Closures. Closures in the air distribution system shall be considered. If one or more spaces of several arranged in parallel can be closed off from the source of the refrigerant leak, their volume(s) shall not be used in the calculation. Exceptions: The following closure devices are not considered: a. smoke dampers, fire dampers, and combination smoke/fire dampers that close only in an emergency not associated with a refrigerant leak; and b. dampers, such as variable-air-volume (VAV) boxes, that provide limited closure where airflow is not reduced below 10% of its maximum (with the fan running). 7.3.2.2 Plenums. The space above a suspended ceiling shall not be included in calculating the refrigerant quantity limit in the system unless such space is part of the air supply or return system. 7.3.2.3 Supply and Return Ducts. The volume of the supply and return ducts and plenums shall be included when calculating the refrigerant quantity limit in the system. 7.4 Location in a Machinery Room or Outdoors. All components containing refrigerant shall be located either in a machinery room or outdoors, where a. b.

the quantity of refrigerant needed exceeds the limits defined by Section 7.2 and Section 7.3 or direct-fired absorption equipment, other than sealed absorption systems not exceeding the refrigerant quantity limits indicated in Table 1 of this standard, is used.

7.4.1 Nonflammable Refrigerants. Machinery rooms required by Section 7.4 shall be constructed and maintained in accordance with Section 8.11 for Group A1 and B1 refrigerants. 7.4.2 Flammable Refrigerants. Machinery rooms required by Section 7.4 shall be constructed and maintained in accordance with Sections 8.11 and 8.12 for Group A2, B2, A3, and B3 refrigerants. 7.5 Additional Restrictions 7.5.1 All Occupancies. Sections 7.5.1.1 through 7.5.1.8 apply to all occupancies. 7.5.1.1 Flammable Refrigerants. The total of all Group A2, B2, A3, and B3 refrigerants other than R-717 (ammonia) shall not exceed 1100 lb (500 kg) without approval by the AHJ. 7.5.1.2 Corridors and Lobbies. Refrigerating systems installed in a public corridor or lobby shall be limited to either a. b.

unit systems containing not more than the quantities of Group A1 or B1 refrigerant indicated in Table 1 or 2 of ASHRAE Standard 341 or sealed absorption and unit systems having refrigerant quantities less than or equal to those indicated in Table 1 of this standard.

7.5.1.3 Refrigerant Type and Purity. Refrigerants shall be of a type specified by the equipment manufacturer unless converted in accordance with Section 7.5.1.8. Refrigerants used in new equipment shall conform to ARI 7003 in purity unless otherwise specified by the equipment manufacturer. 7.5.1.4 Recovered Refrigerants. Recovered refrigerants shall not be reused except in the system from which they were removed or as provided in Sections 7.5.1.5 or 7.5.1.6. When contamination is evident by discoloration, odor, acid test results, or system history, recovered refrigerants shall be reclaimed in accordance with Section 7.5.1.6 before reuse. Table 1 Special Quantity Limits for Sealed Ammonia/Water Absorption and Self-Contained Systems Maximum lb (kg) for Various Occupancies Institutional

Public/Large Mercantile

Residential

Commercial

3.3 (1.5)

Sealed Ammonia/Water Absorption System In public hallways or lobbies

0 (0)

0 (0)

3.3 (1.5)

In adjacent outdoor locations

0 (0)

0 (0)

22 (10)

22 (10)

In other than public hallways or lobbies

0 (0)

6.6 (3)

6.6 (3)

22 (10)

0 (0)

0 (0)

6.6 (3)

22 (10)

Refrigerant Safety

Type of Refrigeration System

Unit Systems In other than public hallways or lobbies

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7.5.1.5 Recycled Refrigerants. Recycled refrigerants shall not be reused except in systems using the same refrigerant and lubricant designation and belonging to the same owner as the systems from which they were removed. When contamination is evident by discoloration, odor, acid test results, or system history, recycled refrigerants shall be reclaimed in accordance with Section 7.5.1.6. Exceptions: Drying is not required in order to use recycled refrigerants where water is the refrigerant, is used as an absorbent, or is a deliberate additive. 7.5.1.6 Reclaimed Refrigerants. Used refrigerants shall not be reused in a different owner’s equipment unless tested and found to meet the requirements of AHRI 700.3 Contaminated refrigerants shall not be used unless reclaimed and found to meet the requirements of AHRI 700. 7.5.1.7 Mixing. Refrigerants, including refrigerant blends, with different designations in ASHRAE Standard 341 shall not be mixed in a system. Exceptions: Addition of a second refrigerant is allowed where specified by the equipment manufacturer to improve oil return at low temperatures. The refrigerant and amount added shall follow the manufacturer’s instructions. 7.5.1.8 Refrigerant or Lubricant Conversion. The type of refrigerant or lubricant in a system shall not be changed without evaluation for suitability, notification to the AHJ and the user, due observance of safety requirements, and replacement or addition of signs and identification as required in Section 11.2.3. 7.5.2 Applications for Human Comfort. Group A2, A3, B1, B2, and B3 refrigerants shall not be used in high-probability systems for human comfort. Exceptions: a. This restriction does not apply to sealed absorption and unit systems having refrigerant quantities less than or equal to those indicated in Table 1 of this standard. b. This restriction does not apply to industrial occupancies. 7.5.3 Higher Flammability Refrigerants. Group A3 and B3 refrigerants shall not be used except where approved by the AHJ. Exceptions: a. This restriction does not apply to laboratories with more than 100 ft2 (9.3 m2) of space per person. b. This restriction does not apply to industrial occupancies. c. This restriction does not apply to listed portable-unit systems containing no more than 0.331 lb (150 g) of Group A3 refrigerant, provided that the equipment is installed in accordance with the listing and the manufacturer’s installation instructions. 8.

INSTALLATION RESTRICTIONS

8.1 Foundations. Foundations and supports for condensing units or compressor units shall be of noncombustible construction and capable of supporting loads imposed by such units. Isolation materials such as rubber are permissible between the foundation and condensing or compressor units. 8.2 Guards. Moving machinery shall be guarded in accordance with approved safety standards.4

Refrigerant Safety

8.3 Safe Access. A clear and unobstructed approach and space shall be provided for inspection, service, and emergency shutdown of condensing units, compressor units, condensers, stop valves, and other serviceable components of refrigerating machinery. Permanent ladders, platforms, or portable access equipment shall be provided in accordance with the requirements of the AHJ. 8.4 Water Connections. Water supply and discharge connections shall be made in accordance with the requirements of the AHJ. 8.5 Electrical Safety. Electrical equipment and wiring shall be installed in accordance with the National Electrical Code5 and the requirements of the AHJ. 8.6 Gas Fuel Equipment. Gas fuel devices and equipment used with refrigerating systems shall be installed in accordance with approved safety standards and the requirements of the AHJ. 8.7 Air Duct Installation. Air duct systems of air-conditioning equipment for human comfort using mechanical refrigeration shall be installed in accordance with approved safety standards, the requirements of the AHJ, and the requirements of Section 8.11.7. 160

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8.8 Refrigerant Parts in Air Duct. Joints and all refrigerant-containing parts of a refrigerating system located in an air duct carrying conditioned air to and from an occupied space shall be constructed to withstand a temperature of 700°F (371.1°C) without leakage into the airstream. 8.9 Refrigerant Pipe Joint Inspection. Refrigerant pipe joints erected on the premises shall be exposed to view for visual inspection prior to being covered or enclosed. 8.10 Location of Refrigerant Piping 8.10.1 Refrigerant piping crossing an open space that affords passageway in any building shall not be less than 7.25 ft (2.2 m) above the floor unless the piping is located against the ceiling of such space and is permitted by the AHJ. 8.10.2 Passages shall not be obstructed by refrigerant piping. Refrigerant piping shall not be placed in any elevator, dumbwaiter, or other shaft containing a moving object or in any shaft that has openings to living quarters or to means of egress. Refrigerant piping shall not be installed in an enclosed public stairway, stair landing, or means of egress. 8.10.3 Refrigerant piping shall not penetrate floors, ceilings, or roofs. Exceptions: a. Penetrations connecting the basement and the first floor. b. Penetrations connecting the top floor and a machinery penthouse or roof installation. c. Penetrations connecting adjacent floors served by the refrigeration system. d. Penetrations of a direct system where the refrigerant concentration does not exceed that listed in Table 1 or 2 of ASHRAE Standard 341 for the smallest occupied space through which the refrigerant piping passes. e. In other than industrial occupancies and where the refrigerant concentration exceeds that listed in Table 1 or 2 of ASHRAE Standard 34 for the smallest occupied space, penetrations that connect separate pieces of equipment that are 1. enclosed by an approved gas-tight, fire-resistive duct or shaft with openings to those floors served by the refrigerating system or 2. located on the exterior wall of a building when vented to the outdoors or to the space served by the system and not used as an air shaft, closed court, or similar space. 8.10.4 Refrigerant piping installed in concrete floors shall be encased in pipe duct. Refrigerant piping shall be properly isolated and supported to prevent damaging vibration, stress, or corrosion.

Refrigerant Safety

8.11 Refrigerating Machinery Room, General Requirements. When a refrigerating system is located indoors and a machinery room is required by Section 7.4, the machinery room shall be in accordance with the following provisions. 8.11.1 Machinery rooms are not prohibited from housing other mechanical equipment unless specifically prohibited elsewhere in this standard. A machinery room shall be so dimensioned that parts are accessible with space for service, maintenance, and operations. There shall be clear head room of not less than 7.25 ft (2.2 m) below equipment situated over passageways. 8.11.2 Each refrigerating machinery room shall have a tight-fitting door or doors opening outward, self-closing if they open into the building and adequate in number to ensure freedom for persons to escape in an emergency. With the exception of access doors and panels in air ducts and air-handling units conforming to Section 8.11.7, there shall be no openings that will permit passage of escaping refrigerant to other parts of the building. 8.11.2.1 Each refrigerating machinery room shall contain a detector, located in an area where refrigerant from a leak will concentrate, that actuates an alarm and mechanical ventilation in accordance with Section 8.11.4 at a value not greater than the corresponding TLV-TWA (or toxicity measure consistent therewith). The alarm shall annunciate visual and audible alarms inside the refrigerating machinery room and outside each entrance to the refrigerating machinery room. The alarms required in this section shall be of the manual reset type with the reset located inside the refrigerating machinery room. Alarms set at other levels (such as IDLH) and automatic reset alarms are permitted in addition to those required by this section. The meaning of each alarm shall be clearly marked by signage near the annunciators. Exceptions: a. For ammonia, refer to Section 8.12(h). b. Detectors are not required when only systems using R-718 (water) are located in the refrigerating machinery room. 161

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8.11.3 Machinery rooms shall be vented to the outdoors, utilizing mechanical ventilation in accordance with Sections 8.11.4 and 8.11.5. 8.11.4 Mechanical ventilation referred to in Section 8.11.3 shall be by one or more powerdriven fans capable of exhausting air from the machinery room at least in the amount given in the formula in Section 8.11.5. To obtain a reduced airflow for normal ventilation, multiple fans or multispeed fans shall be used. Provision shall be made for inlet air to replace that being exhausted. Openings for inlet air shall be positioned to avoid recirculation. Air supply and exhaust ducts to the machinery room shall serve no other area. The discharge of the air shall be to the outdoors in such a manner as not to cause a nuisance or danger. 8.11.5 The mechanical ventilation required to exhaust an accumulation of refrigerant due to leaks or a rupture of the system shall be capable of removing air from the machinery room in not less than the following quantity: Q = 100  G 0.5 where Q = G =

Q = 70  G 0.5

(I-P)

(SI)

airflow, cfm (L/s) mass of refrigerant in the largest system, any part of which is located in the machinery room, lb (kg)

A part of the refrigerating machinery room mechanical ventilation shall be operated, when occupied, to supply at least 0.5 cfm/ft2 (2.54 L/s/m2) of machinery room area or 20 cfm (9.44 L/s) per person and b. operable, when occupied at a volume required to not exceed the higher of a temperature rise of 18°F (10°C) above inlet air temperature or a maximum temperature of 122°F (50°C). When a refrigerating system is located outdoors more than 20 ft (6.1 m) from building openings and is enclosed by a penthouse, lean-to, or other open structure, natural or mechanical ventilation shall be provided. The requirements for such natural ventilation are as follows: a.

a.

The free-aperture cross section for the ventilation of a machinery room shall be at least F = G 0.5 where F = G =

b.

F = 0.138G 0.5

(I-P)

(SI)

2

the free opening area, ft2 (m2 ) the mass of refrigerant in the largest system, any part of which is located in the machinery room, lb (kg) Locations of the gravity ventilation openings shall be based on the relative density of the refrigerant to air.

8.11.6 No open flames that use combustion air from the machinery room shall be installed where any refrigerant is used. Combustion equipment shall not be installed in the same machinery room with refrigerant-containing equipment except under one of the following conditions: a.

Refrigerant Safety

b.

combustion air is ducted from outside the machinery room and sealed in such a manner as to prevent any refrigerant leakage from entering the combustion chamber or a refrigerant detector, conforming to Section 8.11.2.1, is employed to automatically shut down the combustion process in the event of refrigerant leakage.

Exceptions: a. Machinery rooms where only carbon dioxide (R-744) or water (R-718) is the refrigerant. b. Machinery rooms where only ammonia (R-717) is the refrigerant and internal combustion engines are used as the prime mover for the compressors. 8.11.7 There shall be no airflow to or from an occupied space through a machinery room unless the air is ducted and sealed in such a manner as to prevent any refrigerant leakage from entering the airstream. Access doors and panels in ductwork and air-handling units shall be gasketed and tight fitting. 8.11.8 Access. Access to the refrigerating machinery room shall be restricted to authorized personnel. Doors shall be clearly marked or permanent signs shall be posted at each entrance to indicate this restriction. 162

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8.12 Machinery Room, Special Requirements. In cases specified in the rules of Section 7.4, a refrigerating machinery room shall meet the following special requirements in addition to those in Section 8.11: a. b. c.

d. e. f. g.

h.

i.

There shall be no flame-producing device or continuously operating hot surface over 800°F (427°C) permanently installed in the room. Doors communicating with the building shall be approved, self-closing, tight-fitting fire doors. Walls, floor, and ceiling shall be tight and of noncombustible construction. Walls, floor, and ceiling separating the refrigerating machinery room from other occupied spaces shall be of at least one-hour fire-resistive construction. The refrigerating machinery room shall have a door that opens directly to the outdoors or through a vestibule equipped with self-closing, tight-fitting doors. Exterior openings, if present, shall not be under any fire escape or any open stairway. All pipes piercing the interior walls, ceiling, or floor of such rooms shall be tightly sealed to the walls, ceiling, or floor through which they pass. When refrigerants of Groups A2, A3, B2, and B3 are used, the machinery room shall conform to Class 1, Division 2, of the National Electrical Code.5 When refrigerant Groups A1 and B1 are used, the machinery room is not required to meet Class 1, Division 2, of the National Electrical Code. Exceptions: When ammonia is used, the requirements of Class 1, Division 2, of the National Electrical Code shall not apply providing the requirements of Section 8.12(h) are met. When ammonia (R-717) is used, the machinery room is not required to meet Class 1, Division 2, of the National Electrical Code,5 providing (1) the mechanical ventilation system in the machinery room is run continuously and failure of the mechanical ventilation system actuates an alarm or (2) the machinery room is equipped with a detector, conforming to Section 8.11.2.1, except the detector shall alarm at 1000 ppm. Remote control of the mechanical equipment in the refrigerating machinery room shall be provided immediately outside the machinery room door solely for the purpose of shutting down the equipment in an emergency. Ventilation fans shall be on a separate electrical circuit and have a control switch located immediately outside the machinery room door.

8.13 Manual Emergency Discharge of Ammonia Refrigerant. When required by the AHJ, manual emergency discharge or diffusion arrangements for ammonia refrigerants shall be provided. 8.14 Purge Discharge. The discharge from purge systems shall be governed by the same rules as pressure-relief devices and fusible plugs (see Section 9.7.8) and shall be piped in conjunction with these devices. Exceptions: When R-718 (water) is the refrigerant. 9.

DESIGN AND CONSTRUCTION OF EQUIPMENT AND SYSTEMS

9.7.8 For systems in which one or more of the following conditions apply, pressure-relief devices and fusible plugs shall discharge to the atmosphere at a location not less than 15 ft (4.57 m) above the adjoining ground level and not less than 20 ft (6.1 m) from any window, ventilation opening, or exit in any building. a. b. c. d.

Any system containing a Group A3 or B3 refrigerant. Any system containing more than 6.6 lb (3 kg) of a Group A2, B1, or B2 refrigerant. Any system containing more than 110 lb (50 kg) of a Group A1 refrigerant. Any system for which a machinery room is required by the provisions of Section 7.4. Refrigerant Safety

The discharge shall be terminated in a manner that will prevent both the discharged refrigerant from being sprayed directly on personnel in the vicinity and foreign material or debris from entering the discharge piping. Discharge piping connected to the discharge side of a fusible plug or rupture member shall have provisions to prevent plugging the pipe in the event the fusible plug or rupture member functions. Exceptions: When R-718 (water) is the only refrigerant, discharge to a floor drain is also acceptable if all of the following three conditions are met: 1. the pressure relief device set pressure does not exceed 15 psig, 163

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2. the floor drain is sized to handle no less than the flow rate from a single broken tube in any refrigerant-containing heat exchanger, and 3. either: a. the AHJ finds it acceptable that the working fluid, corrosion inhibitor, and other additives used in this type of refrigeration system may infrequently be discharged to the sewer system, or b. a catch tank, sized to handle the expected discharge, is installed and equipped with a normally closed drain valve and an overflow line to drain. 9.7.8.1 The application of pressure-relief valves that discharge from a higher-pressure vessel into a lower-pressure vessel of the system shall comply with (a) through (c) as follows: a.

b.

c.

The pressure-relief valve that protects the higher-pressure vessel shall be selected to deliver capacity in accordance with Section 9.7.5 without exceeding the maximum allowable working pressure of the higher-pressure vessel accounting for the change in mass flow capacity due to the elevated back pressure. The capacity of the pressure-relief valve protecting the part of the system receiving a discharge from a pressure-relief valve protecting a higher-pressure vessel shall be at least the sum of the capacity required in Section 9.7.5 plus the mass flow capacity of the pressurerelief valve discharging into that part of the system. The design pressure of the body of the relief valve used on the higher-pressure vessel shall be rated for operation at the design pressure of the higher-pressure vessel in both pressure-containing areas of the valve.

9.7.8.2 Ammonia Discharge. Ammonia from pressure-relief valves shall be discharged into one or more of the following: a. b.

Refrigerant Safety

c.

The atmosphere, per Section 9.7.8. A tank containing one gallon of water for each pound of ammonia (8.3 liters of water for each kilogram of ammonia) that will be released in one hour from the largest relief device connected to the discharge pipe. The water shall be prevented from freezing. The discharge pipe from the pressure-relief device shall distribute ammonia in the bottom of the tank but no lower than 33 ft (10 m) below the maximum liquid level. The tank shall contain the volume of water and ammonia without overflowing. Other treatment systems that meet the requirements of the AHJ.

9.7.8.3 Optional Sulfur Dioxide Discharge. When sulfur dioxide is used, the discharge shall be into a tank of absorptive solution that shall be used for no other purpose except sulfur dioxide absorption. The absorptive solution shall be one gallon of standard dichromate solution (2.5 pounds of sodium dichromate per gallon of water [300 grams of sodium dichromate per liter of water]) for each pound of sulfur dioxide in the system (8.3 liters of standard dichromate solution for each kilogram of sulfur dioxide in the system). Solutions made with caustic soda or soda ash shall not be used in place of sodium dichromate unless the quantity and strength have the equivalent sulfur-dioxide-absorbing power. The tank shall be constructed of not less than 1/8 in. (3.2 mm) or No. 11 US gage iron or steel. The tank shall have a hinged cover or, if of the enclosed type, shall have a vent hole at the top. All pipe connections shall be through the top of the tank only. The discharge pipe from the pressure-relief valve shall discharge the sulfur dioxide in the center of the tank near the bottom. 9.7.8.4 The size of the discharge pipe from a pressure-relief device or fusible plug shall not be less than the outlet size of the pressure-relief device or fusible plug. Where outlets of two or more relief devices or fusible plugs are connected to a common line or header, the effect of back pressure that will be developed when more than one relief device or fusible plug operates shall be considered. The sizing of the common discharge header downstream from each of the two or more relief devices or fusible plugs that are expected to operate simultaneously shall be based on the sum of their outlet areas with due allowance for the pressure drop in all downstream sections. The maximum length of the discharge piping installed on the outlets of pressure-relief devices and fusible plugs discharging to the atmosphere shall be determined by the method in Normative Appendix E. See Table 3 for the flow capacity of various equivalent lengths of discharge piping for conventional relief valves.

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11.

REFRIGERATION LOAD

The overall coefficient of heat transfer U of the wall, floor, or ceiling of a refrigerated space can be derived from: 1 U = ---------------------------------------------------------------------1  fi + x1  k1 + x2  k2 + 1  fo where U x k fi fo

= = = = =

Refrigeration Load

Transmission Load

overall heat transfer coefficient, Btu/hft2°F wall thickness, in. thermal conductivity of wall material, Btuin/hft2°F inside film or surface conductance, Btu/hft2°F outside film or surface conductance, Btu/hft2°F

1.65 Btu/hft2°F for fi and fo is frequently used for still air. If the outer surface is exposed to 15 mph wind, fo is increased to 6 Btu/hft2°F. With thick walls and low conductivity, the resistance x/k makes U so small that l/fp have little effect and can be omitted from the calculation. After establishing U, the heat gain is given by the basic equation: q = UAt where q = A = t =

heat leakage, Btu/h outside area of section, ft2 difference between outside air temperature and air temperature of the refrigerated space, °F

Latent heat gain due to moisture transmission through walls, floors, and ceilings of modernconstruction refrigerated facilities is negligible. Table 11.1 Thermal Conductivity of Insulation for Walls, Floor, and Ceiling, Btuin/hft2°F Polyurethane (Expanded) k = 0.16

Polyurethane (Board) k = 0.18

Polystyrene (Extruded) k = 0.20

Glass Fiber and Polystyrene (Molded Beads) k = 0.33

Cellular Glass k = 0.28

Table 11.2 Minimum Insulation Thickness Storage Temperature °F 50 25 15

Expanded Polyurethane Thickness in. 2 3 5

Table 11.3 Sun Effect Typical Surface Types Dark colored surfaces Medium colored surfaces Light colored surfaces

East Wall °F 8 6 4

South Wall °F 5 4 2

West Wall °F 8 6 4

Flat Roof °F 20 15 9

Note: Add °F to the normal temperature difference for heat leakage calculations to compensate for sun effect—do not use for air-conditioning design. 165

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Product Load Refrigeration Load

1. Heat removal in cooling from the initial temperature to a freezing point of the product: Q1 = mc1(t1 – t2) 2. Heat removal to freeze the product: Q2 = mhif 3. Heat removal in cooling from the freezing point to the final temperature below the freezing point: Q3 = mc2 (tf – t2) where Q1, Q2, Q3, Q4 m c1 t1 t2 tf hif c2 t3

= = = = = = = = =

heat removal, Btu weight of the product, lb specific heat of the product above freezing, Btu/lb°F initial temperature of the product above freezing, °F lower temperature of the product above freezing, °F freezing temperature of the product, °F latent heat of fusion of the product, Btu/lb specific heat of the product below freezing, Btu/lb°F final temperature of the product below freezing, °F

Specific heats above and below freezing for many products are given in Table 3 of Chapter 19 in 2010 ASHRAE Handbook—Refrigeration. Refrigeration system capacity for products brought into refrigerated spaces is determined from the time allotted for heat removal and assumes that the product is properly exposed to remove the heat in that time. The calculation is: Q1 + Q2 + Q3 q = --------------------------------n where q = n =

product cooling load, Btu/h allotted time period, h

A product’s latent heat of fusion is related to its water content and can be estimated by multiplying the product’s percent of water (expressed as a decimal) by the water’s latent heat of fusion, 144 Btu/lb. Most food products freeze in the range of 26 to 31°F. When the exact freezing temperature is not known, assume that it is 28°F.

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Internal Load Heat Equivalent of Electric Motors

Connected Load Outside Refrigerated Space Btu/hph Btu/hph Btu/hph 1/8 to 1/3 4600 2550 2100 1/2 to 3 3800 2550 1300 5 to 20 3300 2550 800 Approximate Heat Equivalent of Occupancy Per Person qp = 1295 – 11.5t where qp = heat gain per person, Btu/h t = refrigerated space temperature, °F Motor hp

Connected Load in Refrigerated Space

Motor Losses Outside Refrigerated Space

Refrigeration Load

Table 11.4

Infiltration Air Load Heat gain through doorways from air exchange is: qt = qDt Df (1 – E) where qt q Dt Df E

= = = = =

average heat gain for the 24-h or other period, Btu/h sensible and latent refrigeration load for fully established flow, Btu/h doorway open-time factor doorway flow factor effectiveness of doorway protective device q = 3790 WH1.5 (Qs/A)(1/Rs )

where Qs/A = W H Rs

= = =

sensible heat load of infiltration air per square foot of doorway opening as read from Figure 11.1, ton/ft2 doorway width, ft doorway height, ft sensible heat ratio of the infiltration air heat gain, from a psychrometric chart

Doorway open-time factor Dt can be calculated as follows:  P p + 60o  D t = -------------------------------3600 d where Dt P p o d

= = = = =

decimal portion of time doorway is open number of doorway passages door open-close time, seconds per passage time door simply stands open, min the daily (or other) time period, h

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Refrigeration Load


Figure 11.1

Sensible Heat Gain by Air Exchange for Continuously Open Door with Fully Established Flow [2010R, Ch 24, Fig 5]

Equipment-Related Load Equipment-related load consists essentially of fan heat where forced air circulation is used, reheat where humidity control is provided, defrosting heat gain where defrosting occurs, and moisture evaporation where the defrosting process is exposed to refrigerated air. To accurately select heat-extracting equipment, a distinction should be made between those equipment heat loads that are felt within the refrigerated space and those that are introduced directly to the refrigerating fluid. Equipment heat gain is usually minor at space temperatures above approximately 30°F, but may be up to 15%.

Safety Factor Generally, a 10% safety factor is applied to the calculated load to allow for possible discrepancies between the design criteria and actual operation. Refrigeration system capacity should be sufficient to handle the load with the actual running time, allowing for defrost cycles. 168

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Forced-Circulation Air Coolers

Figure 11.2

Refrigeration Load

Cooling coil and motor-driven fan are the basic components and coil defrosting means are added for low-temperature operations where coil frosting might impede performance. Blowthrough direct-drive propeller fans are most common, but for long throws, draw-through configuration is preferred. For loads above 32°F, coil spacing is usually 6 to 8 fins per inch; below 32°F a maximum of 4 fins per inch is preferred. Even distribution of halocarbon refrigerant is usually attained in direct-expansion coils by refrigerant distributors. Units in larger refrigeration systems are often liquid-pumped recirculating types with orifice disks. Defrost for coils and drain pans of low-temperature units may be hot-gas, electric, or water. Usually defrosting is done with the fan off. Control of defrost is usually by microprocessor, with a thermostat mounted within the coil. Usually a rise to 45°F returns the unit to the operating cycle. Drain lines should be well-pitched, insulated, and trapped outside the refrigerated space. Capacities of air coolers are usually based on the temperature difference between inlet air and refrigerant in the coil. The higher the TD, the lower the space relative humidity. Between 8°F and 16°F TD is usual, except for packaged products and workrooms where TD of 25°F is common. Low-temperature units generally have TD below 15°F for system economics and limiting defrost frequency. Most frequent control of refrigerant flow is an expansion valve, most frequently thermostatic type. Electric expansion valves, requiring a valve, controller, and control sensor, are also available. Large refrigerating systems more frequently have flooded evaporators, most often low-side float valves. Refrigerant valves opening or closing flow are usually solenoid valves. Larger flows may require pilot-operated solenoid valves. When it is desired to limit compressor motor load during pulldown, an evaporator pressure regulating valve may be used to limit compressor suction pressure.

Low-Profile Cooler

Figure 11.3 Liquid Overfeed Type Unit Cooler 169

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12.

AIR-CONDITIONING LOAD DATA

Air-Conditioning Load Data

Cooling Loads Obtain appropriate weather data and select design conditions. In addition to the conventional dry-bulb with mean coincident wet-bulb, also consider dew-point with mean coincident dry-bulb, particularly with spaces requiring large amounts of outdoor air or close control of moisture. Select indoor dry-bulb, wet-bulb, and ventilation rate, including permissible variations and control limits. Consider proposed schedules of occupancy, lighting, and processes that contribute to the internal load. Several different times of day and months must frequently be analyzed to determine the peak load time. ANSI/ASHRAE/ACCA Standard 183-2007 sets the minimum standards for nonresidential load calculations. Currently there are two ASHRAE cooling load calculation methods. The first is the Heat Balance (HB) method, whose equations are coded in a generic computer program linked to a user interface program. The source code for these programs is in the ASHRAE Load Calculation Toolkit. The second method is the Radiant Time Series (RTS) method, a simplification of the heat balance method, still requiring a complex computer program for a multiroom building. Due to the variation in heat transfer coefficients, precision of construction, and manner of actual building operation, a cooling load calculation can never be more than a good estimate of the actual load. For preliminary estimation of the cooling load, the figures herein are a very rough guide. The approximate cooling load calculation methods presented here are useful to the experienced designer. To design and size components of central air-conditioning systems, more than the cooling load is needed. Type of system, fan energy and location, direct heat loss and gain, duct leakage, heat extracted from lights, and type of return system must all be considered.

Heating Loads Similar calculations to cooling load are made, but temperatures outside conditioned spaces are usually lower than space temperatures maintained. Solar heat gains, and internal heat gains are not included and thermal storage of building structure or content is usually ignored. This is usually sufficient to cope with a worst-case situation. There is very often need for cooling in cold months, for perimeter spaces with high solar heat gain and interior spaces with significant heat gain.

Previous Cooling Load Calculation Methods Procedures described in Chapters 17 and 18 of the 2013 ASHRAE Handbook–Fundamentals are the most current and scientifically derived means for estimating cooling load for a defined building space, but methods in earlier editions of the ASHRAE Handbook are valid for many applications. These earlier procedures are simplifications of the Heat Balance principles, and their use requires experience to deal with atypical or unusual circumstances. In fact, any cooling or heating load estimate is no better than the assumptions used to define conditions and parameters such as physical makeup of the various envelope surfaces, conditions of occupancy and use, and ambient weather conditions. Experience of the practitioner can never be ignored. The primary difference between the HB and RTS methods and the older methods is the newer methods’ direct approach, compared to the simplifications necessitated by the limited computer capability available previously. The transfer function method (TFM), for example, required many calculation steps. It was originally designed for energy analysis with emphasis on daily, monthly, and annual energy use, and thus was more oriented to average hourly cooling loads than peak design loads. The total equivalent temperature differential method with time averaging (TETD/TA) has been a highly reliable (if subjective) method of load estimating since its initial presentation in the 1967 Handbook of Fundamentals. Originally intended as a manual method of calculation, it proved suitable only as a computer application because of the need to calculate an extended profile of hourly heat gain values, from which radiant components had to be averaged over a time representative of the general mass of the building involved. Because perception of thermal storage characteristics of a given building is almost entirely subjective, with little specific information for the user to judge variations, the TETD/TA method’s primary usefulness has always been to the experienced engineer. 170

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The cooling load temperature differential method with solar cooling load factors (CLTD/CLF) attempted to simplify the two-step TFM and TETD/TA methods into a single-step technique that proceeded directly from raw data to cooling load without intermediate conversion of radiant heat gain to cooling load. A series of factors were taken from cooling load calculation results (produced by more sophisticated methods) as “cooling load temperature differences” and “cooling load factors” for use in traditional conduction (q = UAt) equations. The results are approximate cooling load values rather than simple heat gain values. The simplifications and assumptions used in the original work to derive those factors limit this method’s applicability to those building types and conditions for which the CLTD/CLF factors were derived; the method should not be used beyond the range of applicability. The TFM, TETD/TA, and CLTD/CLF procedures have not been invalidated or discredited. Experienced engineers have successfully used them in millions of buildings around the world. The accuracy of cooling load calculations in practice depends primarily on the availability of accurate information and the design engineer’s judgment in the assumptions made in interpreting the available data. Those factors have much greater influence on a project’s success than does the choice of a particular cooling load calculation method. The primary benefit of HB and RTS calculations is their somewhat reduced dependency on purely subjective input (e.g., determining a proper time-averaging period for TETD/TA; ascertaining appropriate safety factors to add to the rounded-off TFM results; determining whether CLTD/ CLF factors are applicable to a specific unique application). However, using the most up-to-date techniques in real-world design still requires judgment on the part of the design engineer and care in choosing appropriate assumptions, just as in applying older calculation methods.

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Lights and Other Electrical W/ft2 Lo Av Hi Refrigeration ft2/ton† Lo Av Hi

Supply Air Rate East-South-West Lo Av Hi Lo

Table 12.1 Cooling Load Check Figures


North Av Hi

— 3.0 1.9 5.5 3.8 6.5 1.3 1.1 — 1.1 1.2 1.4 2.0 — — 1.4 1.3

2.0 2.5

— 2.0 1.2 3.6 2.5 4.0 1.0 1.0 — 1.0 1.0 1.2 1.3 — — 1.1 1.0

1.3 1.8

cfm/ft2 Internal Lo Av Hi

Apartment, High Rise 325 175 100 0.7 0.9 1.1 450 400 350 0.8 1.2 1.7 0.5 0.8 1.3 — Auditoriums, Churches, Theaters 15 11 6 0.5 0.7 0.9 400 250 90 — — — — — — 1.0 Educational Facilities 30 25 20 0.75 1.0 1.1 240 185 150 1.0 1.6 2.2 0.9 1.3 2.0 0.8 Schools, Colleges, Universities Factories Assembly Areas 50 35 23 2.5† 4.0† 5.5† 240 150 90 — — — — — — 2.0 Light Manufacturing 200 150 100 7.5† 9† 11† 200 150 100 — — — — — — 1.6 Heavy Manufacturing* 200 250 300 12† 25† 30† 100 80 60 — — — — — — 2.5 Hospitals Patient Rooms 70 50 25 0.5 0.75 1.0 275 220 165 1.0 1.5 2.0 0.8 1.2 1.4 0.7 Public Areas 100 80 50 0.5 0.75 1.0 175 140 110 1.0 1.25 1.45 1.0 1.1 1.2 0.95 Hotels, Motels, Dormitories 200 150 100 0.5 0.75 1.0 350 300 220 1.0 1.40 1.5 0.9 1.2 1.4 — Libraries and Museums 80 60 40 0.5 0.75 1.0 340 280 200 1.0 1.6 2.1 0.9 1.1 1.3 0.9 Office Buildings (General) 130 110 80 2† 2.5† 4† 360 280 190 1.0 1.6 2.2 0.9 1.3 2.0 0.8 Private Offices 150 125 100 0.5 0.75 1.0 — — — 1.2 1.8 2.4 1.1 1.5 1.8 0.8 Stenographic Department 100 85 70 1.0 1.25 1.5 — — — — — — — — — 0.9 Residential Large 600 400 200 0.5 1.0 1.5 600 500 380 0.8 1.2 1.6 0.5 0.8 1.3 — Medium 600 360 200 0.5 1.0 1.5 700 550 400 0.7 1.1 1.4 0.5 0.7 1.2 — Restaurants Large 17 15 13 0.5 1.0 1.5 135 100 80 1.8 2.4 3.7 1.2 1.6 2.1 0.9 Medium 150 120 100 1.5 2.0 3.0 1.1 1.4 1.8 0.9 Shopping Centers, Department Stores and Specialty Shops Beauty and Barber Shops 45 40 25 3.0† 5.0† 9.0† 240 160 105 1.5 2.6 4.2 1.1 1.7 2.6 0.9 Malls 100 75 50 1.0 1.5 2.0 365 230 160 — — — — — — 1.1 Refrigeration for Central Heating and Cooling Plant Urban Districts 475 380 285 College Campuses 400 320 240 Commercial Centers 330 265 200 Residential Centers 625 500 375 Refrigeration and air quantities for applications listed in this table of cooling load check figures are based on all-air system and normal outdoor air quantities for ventilation except as noted. †Refrigeration loads are for entire application *Air quantities for heavy manufacturing areas are based on supplementary means to remove excessive heat.

Classifications

Occupancy ft2/Person Lo Av Hi

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Table 12.2 Summary of Load Sources and Equations for Estimating Space Design Cooling Load

Equation

Reference, Table, Description

q = UA(CLTD)

Walls

q = UA(CLTD)

Design heat transmission coefficients, pp. 179–84 Areas calculated from plans CLTD, pp. 185–86 Design heat transmission coefficients, pp. 179–84 Areas calculated from plans CLTD, pp. 187–89 Glass area calculated from plans U-factors p. 174 CLTD for conduction load through glass, p. 174 Solar Cooling Load factors, pp. 190–91 Net glass area from plans Shading coefficients for combination of glass and internal shading, p. 192 Compute shaded area from building projections Externally shaded glass: use north orientation data

Glass Conduction q = UA(CLTD)

Glass Solar

q = A(SC)SCL

Partitions, Ceilings, Floors

q = UA(TD)

Design heat transmission coefficients, pp. 179–84 Area calculated from plans

Internal Lights

q = INPUT

Input rating from electrical plans or lighting fixture data, pp. 194–96

People Sensible

qs = No. (Sens. H.G.) ql = No. (Lat. H.G.) qs = HEAT GAIN

Number of people in space Sensible heat gain from occupants, p. 193 Latent heat gain from occupants Recommended rate of heat gain, pp. 197–210

q = HEAT GAIN

pp. 198–99

qs = 1.10 (CFM) t ql = 4840 (CFM) W

Inside-outside air temperature difference, °F Inside-outside air humidity ratio difference, grains/lbda Inside-outside air enthalpy difference, Btu/lbda

Latent Equipment and Appliances Power Infiltration Air Sensible Latent Total

q = 4.5 (CFM) h


Load Source External Roof

CAUTION: Approximate data—Use for preliminary computations only. See ASHRAE Cooling and Heating Load Calculation Applications Manual (Spitler 2008), and ASHRAE Load Calculation Toolkit.

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Heat Flow Q Through Building Materials (In addition to heat flow through building materials the resistance of surfaces and air spaces must be included in calculating U-factors.) Q (Btu/h) = U  Area (ft2)  temperature difference (°F) where U = overall coefficient of heat transmission, Btu/hft2°F, of materials + interior and exterior resistances: 1/U = R (resistance of components) For multiple layers of homogeneous materials, R values are added in series: Air-Conditioning Load Data

1/U = Rcold surface + R1 + R2 + Rn... + Rwarm surface For wood stud walls, studs 16 in. on center (series and parallel): 1/U = Rcold surface +

 + 0.25 R stud   -----------------------------------------------  + Rwarm surface  + 0.75 R stud space 

(Plus, in series, Rinsulation, Rsiding, Rwallboard, etc.) For metal framed construction, heat flow through the metal causes thermal bridging, increasing the U-factor significantly.

Conductive Heat Flow Through Glazing Solar radiation gain through glazing is usually more significant in cooling load calculations than conductive heat gain. Solar heat gain is neglected in heating load calculations. Conductive heat flow through glazing including surface resistance (approximate data) Single glazing U = 1.1 Double glazing U = 0.55 Triple glazing U = 0.33

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Table 12.3

Effective Thermal Resistance of Plane Air Spaces, [2013F, Ch 26, Tbl 3]

Effective Emittance effd,e 0.75 in. Air Spacec 0.5 in. Air Spacec 0.03 0.05 0.2

0.5 0.82 0.03 0.05 0.2

0.5 0.82

2.13 1.62 2.13 1.73 2.10 1.69 2.04 2.47 2.57 2.66 2.82 2.93 2.90 3.20 2.48 2.66 2.67 2.94 2.96 3.25 3.28

0.99 0.96 1.11 1.12 1.27 1.23 1.40 1.06 1.23 1.24 1.50 1.53 1.76 1.87 1.06 1.24 1.25 1.53 1.53 1.89 1.90

1.04 0.99 1.16 1.16 1.31 1.27 1.46 1.22 1.30 1.43 1.58 1.73 1.77 2.04 1.22 1.44 1.45 1.81 1.82 2.28 2.30

2.03 1.57 2.05 1.70 2.04 1.66 2.00 2.34 2.46 2.54 2.72 2.82 2.82 3.10 2.34 2.54 2.55 2.83 2.85 3.15 3.18

1.51 1.29 1.60 1.45 1.70 1.49 1.75 1.67 1.84 1.88 2.14 2.20 2.35 2.54 1.67 1.88 1.89 2.20 2.22 2.58 2.60

0.73 0.75 0.84 0.91 1.00 1.04 1.16 0.77 0.90 0.91 1.13 1.15 1.39 1.46 0.77 0.91 0.92 1.15 1.16 1.47 1.47

2.34 1.71 2.30 1.83 2.23 1.77 2.16 3.50 2.91 3.70 3.14 3.77 2.90 3.72 3.55 3.77 3.84 4.18 4.25 4.60 4.71

2.22 1.66 2.21 1.79 2.16 1.74 2.11 3.24 2.77 3.46 3.02 3.59 2.83 3.60 3.29 3.52 3.59 3.96 4.02 4.41 4.51

1.61 1.35 1.70 1.52 1.78 1.55 1.84 2.08 2.01 2.35 2.32 2.64 2.36 2.87 2.10 2.38 2.41 2.83 2.87 3.36 3.42

0.75 0.77 0.87 0.93 1.02 1.07 1.20 0.84 0.94 1.01 1.18 1.26 1.39 1.56 0.85 1.02 1.02 1.30 1.31 1.69 1.71


Air Space Direction of Mean Temp. Heat Temp.d, Diff.,d Flow °F °F 90 10 50 30 Up 50 10 Horiz. 0 20 0 10 50 20 50 10 90 10 50 30 Horiz. 50 10 Vertical 0 20 0 10 50 20 50 10 90 10 50 30 Down 50 10 Horiz. 0 20 0 10 50 20 50 10

Position of Air Space

h·ft ·°F/Btu

a

See Chapter 25 of ASHRAE Handbook—Fundamentals (2013). Thermal resistance values were determined from R = 1/C, where C = hc + eff hr , hc is conduction/convection coefficient, eff hr is radiation coefficient  0.0068eff [(tm + 460)/100]3, and tm is mean temperature of air space. b Values apply for ideal conditions (i.e., air spaces of uniform thickness bounded by plane, smooth, parallel surfaces with no air leakage to or from the space). This table should not be used for hollow siding or profiled cladding. c A single resistance value cannot account for multiple air spaces; each air space requires a separate resistance calculation that applies only for established boundary conditions. Resistances of horizontal spaces with heat flow downward are substantially independent of temperature difference. d Interpolation is permissible for other values of mean temperature, temperature difference, and effective emittance eff. Interpolation and moderate extrapolation for air spaces greater than 3.5 in. are also permissible. e Effective emittance eff of air space is given by 1/eff = 1/1 + 1/2  1, where 1 and 2 are emittances of surfaces of air space (see Table 2). Also, oxidation, corrosion, and accumulation of dust and dirt can dramatically increase surface emittance. Emittance values of 0.05 should only be used where the highly reflective surface can be maintained over the service life of the assembly.

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Table 12.4

Surface Film Coefficients/Resistances [2013, Ch 26, Tbl 10]

Direction of Heat Flow

Position of Surface


Reflective  = 0.20

 = 0.05

hi

Ri

hi

Ri

hi

Ri

Upward

1.63

0.61

0.91

1.10

0.76

1.32

Indoor Horizontal

Surface Emittance,  Nonreflective  = 0.90

Sloping at 45°

Upward

1.60

0.62

0.88

1.14

0.73

1.37

Vertical

Horizontal

1.46

0.68

0.74

1.35

0.59

1.70

Sloping at 45°

Downward

1.32

0.76

0.60

1.67

0.45

2.22

Horizontal

Downward

1.08

0.92

0.37

2.70

0.22

4.55

ho

Ro

Outdoor (any position) 15 mph wind (for winter)

Any

6.00

0.17

—

—

—

—

7.5 mph wind (for summer)

Any

4.00

0.25

—

—

—

—

Notes: 1. Surface conductance hi and ho measured in Btu/h·ft2 ·°F; resistance Ri and Ro in h·ft2 ·°F/Btu. 2. No surface has both an air space resistance value and a surface resistance value. 3. Conductances are for surfaces of the stated emittance facing virtual blackbody surroundings at same temperature as ambient air. Values based on surface/air temperature difference of 10°F and surface temperatures of 70°F. 4. See Chapter 4 for more detailed information. 5. Condensate can have significant effect on surface emittance (see Table 2). Also, oxidation, corrosion, and accumulation of dust and dirt can dramatically increase surface emittance. Emittance values of 0.05 should only be used where highly reflective surface can be maintained over the service life of the assembly.

Table 12.5

European Surface Film Coefficients/Resistances [2013, Ch 26, Tbl 11]

Position of Surface Indoors Horizontal, sloping to 45° Vertical, sloping beyond 45° Outdoors

Direction of Heat Flow Upward Downward Any direction

h, Btu/h·ft2 · °F

R, h·ft2 · °F/Btu

1.76 1.06 1.36 4.4

0.57 0.97 0.74 0.23

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Table 12.6

Emissivity of Various Surfaces and Effective Emittances of Facing Air Spacesa [2013F, Ch 26, Tbl 2]

Surface

Effective Emittance eff of Air Space One Surface’s Both Surfaces’ Emittance ; Emittance  Other, 0.9

0.05

0.05

0.03

0.30b

0.29

—

b

0.65

—

0.12 0.20 0.04 0.74 0.04 0.2 0.58 0.27 0.06 0.03 0.25 0.05 0.50

0.12 0.20 0.038 0.41 0.038 0.16 0.35 0.21 0.056 0.029 0.24 0.047 0.47

0.06 0.11 0.02 0.59 0.02 0.11 0.41 0.16 0.03 0.015 0.15 0.026 0.35

0.90

0.82

0.82

0.84

0.77

0.72

0.70


Aluminum foil, bright Aluminum foil, with condensate just visible (>0.7 g/ft2) Aluminum foil, with condensate clearly visible (>2.9 g/ft2) Aluminum sheet Aluminum-coated paper, polished Brass, nonoxidized Copper, black oxidized Copper, polished Iron and steel, polished Iron and steel, oxidized Lead, oxidized Nickel, nonoxidized Silver, polished Steel, galvanized, bright Tin, nonoxidized Aluminum paint Building materials: wood, paper, masonry, nonmetallic paints Regular glass

Average Emissivity 

Values apply in 4 to 40 m range of electromagnetic spectrum. Also, oxidation, corrosion, and accumulation of dust and dirt can dramatically increase surface emittance. Emittance values of 0.05 should only be used where the highly reflective surface can be maintained over the service life of the assembly. Except as noted, data from VDI (1999). b Values based on data in Bassett and Trethowen (1984). a

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Table 12.7

Effective Thermal Resistance of Ventilated Attics (Summer Condition)

80

120 140 160

Natural Power Ventilationc Ventilation Ventilation Rate, cfm/ft2 0 0.1 0.5 1.0 1.5 Ceiling Resistance Rd, °F·ft2 ·h/Btu 10 20 10 20 10 20 10 20 10 20 Part A. Nonreflective Surfaces 1.9 1.9 2.8 3.4 6.3 9.3 9.6 16 11 20 1.9 1.9 2.8 3.5 6.5 10 9.8 17 12 21 1.9 1.9 2.8 3.6 6.7 11 10 18 13 22

100

120 140 160

1.9 1.9 1.9

80

120 140 160

100

120 140 160

Not Ventilationb e


Ventilation Sol-Air Air Temp., Temp., °F °F

4.0 5.8 7.2

6.0 8.7 11

4.1 6.5 8.3

6.9 10 13

6.5 6.5 6.5

1.9 2.2 2.3 3.3 4.4 1.9 2.4 2.7 4.2 6.1 1.9 2.6 3.2 5.0 7.6 Part B. Reflective Surfacesf 6.5 8.1 8.8 13 17 6.5 8.2 9.0 14 18 6.5 8.3 9.2 15 18

17 18 19

25 26 27

19 20 21

30 31 32

6.5 6.5 6.5

6.5 6.5 6.5

8.5 11 13

12 15 18

8.8 12 15

12 16 20

7.0 7.3 7.6

7.4 7.8 8.2

8.0 10 11

10 12 14

a

Although the term effective resistance is commonly used when there is attic ventilation, this table includes values for situations with no ventilation. The effective resistance of the attic added to the resistance (1/U) of the ceiling yields the effective resistance of this combination based on sol-air and room temperatures. These values apply to wood frame construction with a roof deck and roofing that has a conductance of 1.0 Btu/h·ft2·°F. b This condition cannot be achieved in the field unless extreme measures are taken to tightly seal the attic. c Based on air discharging outward from attic. d When determining ceiling resistance, do not add the effect of a reflective surface facing the attic, as it is accounted for in part B of this table. e Roof surface temperature rather than sol-air temperature can be used if 0.25 is subtracted from the attic resistance shown. f Surfaces with effective emittance eff = 0.05 between ceiling joists facing attic space.

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Table 12.8

Building and Insulating Materials: Design Values [2013F, Ch 26, Tbl 1]

Description

Density, lb/ft3

Resistance R, h·ft2 ·°F/Btu

Specific Heat cp, Btu/lb·°F

0.32 to 0.33 0.28 to 0.30 0.26 to 0.27 0.23 — 0.25 to 0.26 0.23 to 0.24 0.28 0.24

— — — — — — — — —

0.2 — — — — 0.2 — — — —

Insulating Materials Blanket and batt c,d Glass-fiber batts .............................................. 0.47 to 0.51 0.61 to 0.75 0.79 to 0.85 1.4 Rock and slag wool batts. ............................... — 2 to 2.3 2.8 Mineral wool, felted ....................................... 1 to 3 1 to 8 Board and slabs Cellular glass .................................................. Cement fiber slabs, shredded wood with Portland cement binder ................................ with magnesia oxysulfide binder ................. Glass fiber board............................................. Expanded rubber (rigid).................................. Extruded polystyrene, smooth skin ................ aged per Can/ULC Standard S770-2003 ..... aged 180 days .............................................. European product......................................... aged 5 years at 75°F..................................... blown with low global warming potential (GWP) (<5) blowing agent ....................... Expanded polystyrene, molded beads ............ Mineral fiberboard, wet felted ........................ Rock wool board............................................. floors and walls............................................ roofing.......................................................... Acoustical tilee ................................................ Perlite board.................................................... Polyisocyanurate............................................. unfaced, aged per Can/ULC Standard S7702003........................................................... with foil facers, aged 180 days .................... Phenolic foam board with facers, aged........... Loose fill Cellulose fiber, loose fill ................................ attic application up to 4 in. ......................... attic application > 4 in. ............................... wall application, densely packed ................. Perlite, expanded ............................................

Glass fiberd attics, ~4 to 12 in.......................................... attics, ~12 to 22 in........................................ closed attic or wall cavities.......................... Rock and slag woold attics, ~3.5 to 4.5 in...................................... attics, ~5 to 17 in.......................................... closed attic or wall cavities ......................... Vermiculite, exfoliated ................................... Spray applied Cellulose, sprayed into open wall cavities .. Glass fiber, sprayed into open wall or attic cavities ......................................................


Conductivityb k, Btu·in/h·ft2 ·°F

7.5

0.29

—

0.20

25 to 27 22 — 1.5 to 6.0 4 — 1.4 to 3.6 1.4 to 3.6 1.9 2 to 2.2

0.50 to 0.53 0.57 — 0.23 to 0.24 0.2 — 0.18 to 0.20 0.20 0.21 0.21

— — — — — — —

— 0.31 0.2 — 0.4 0.35 —

—

—

— 1.0 to 1.5 1.8 10 — 4.0 to 8.0 10. to 11. 21 to 23 9 —

0.24 to 0.25 — 0.24 to 0.26 0.23 0.26 — 0.23 to 0.25 0.27 to 0.29 0.36 to 0.37 0.36 —

— — — — — — — — — — —

— 0.35 — — 0.2 0.2 — 0.2 0.14 to 0.19 — 0.35

1.6 to 2.3 — —

0.16 to 0.17 0.15 to 0.16 0.14 to 0.16

— — —

— — —

— 1.0 to 1.2 1.2 to 1.6 3.5 2 to 4 4 to 7.5 7.5 to 11

— 0.31 to 0.32 0.27 to 0.28 0.27 – 0.28 0.27 to 0.31 0.31 to 0.36 0.36 to 0.42

— — — — — — —

0.33 — — — 0.26 — —

0.4 to 0.5 0.5 to 0.6 1.8 to 2.3

0.36 to 0.38 0.34 to 0.36 0.24 to 0.25

— — —

— — —

1.5 to 1.6 1.5 to 1.8 4.0 7.0 to 8.2 4.0 to 6.0

0.34 0.32 to 0.33 0.27 to 0.29 0.47 0.44

— — — — —

— — — 0.32 —

1.6 to 2.6

0.27 to 0.28

—

—

0.27 to 0.29 0.23 to 0.26 — 0.26 to 0.29 0.14 to 0.20

— — — — —

— — 0.35 — —

1.0 1.8 to 2.3 Polyurethane foam ......................................... — low density, open cell ................................. 0.45 to 0.65 medium density, closed cell, aged 180 days 1.9 to 3.2

179

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Table 12.8

Building and Insulating Materials: Design Values [2013F, Ch 26, Tbl 1] (Continued)

Description


Building Board and Siding Board Asbestos/cement board .................................. Cement board ................................................. Fiber/cement board ........................................

Gypsum or plaster board ................................ Oriented strand board (OSB) ............ 7/16 in. ............................................................. 1/2 in. Plywood (douglas fir).......................... 1/2 in. ............................................................. 5/8 in. Plywood/wood panels ......................... 3/4 in. Vegetable fiber board sheathing, regular density................. 1/2 in. intermediate density ...................... 1/2 in. nail-based sheathing ......................... 1/2 in. shingle backer................................... 3/8 in. sound-deadening board ..................... 1/2 in. tile and lay-in panels, plain or acoustic....... laminated paperboard .................................. homogeneous board from repulped paper... Hardboard medium density ........................................... high density, service-tempered and service grades ....................................................... high density, standard-tempered grade ....... Particleboard low density .................................................. medium density ........................................... high density ................................................. underlayment.................................... 5/8 in. Waferboard..................................................... Shingles Asbestos/cement.......................................... Wood, 16 in., 7 1/2 in. exposure ................. Wood, double, 16 in., 12 in. exposure ........ Wood, plus ins. backer board......... 5/16 in.

Density, lb/ft3




120 71 88 61 26 20 40 41 41 29 34 28

4 1.7 1.7 1.3 0.5 0.4 1.1 — — — — —

— — — — — — — 0.62 0.68 0.79 0.85 1.08

0.24 0.2 0.2 0.2 0.45 0.45 0.21 0.45 0.45 0.45 0.45 0.45

18 22 25 18 15 18 30 30

— — — — — 0.4 0.5 0.5

1.32 1.09 1.06 0.94 1.35 — — —

0.31 0.31 0.31 0.3 0.3 0.14 0.33 0.28

50

0.73

—

0.31

55 63

0.82 1.0

— —

0.32 0.32

37 50 62 44 37

0.71 0.94 1.18 0.73 0.63

— — 0.85 0.82 0.21

0.31 0.31 — 0.29 0.45

120 — — —

— — — —

0.21 0.87 1.19 1.4

— 0.31 0.28 0.31

— — — — —

— — — — —

0.21 0.15 0.21 0.15 0.79

0.24 0.35 0.24 0.35 0.28

Siding Asbestos/cement, lapped .................. 1/4 in. Asphalt roll siding ....................................... Asphalt insulating siding (1/2 in. bed) ........ Hardboard siding............................ 7/16 in. Wood, drop, 8 in.................................. 1 in. Wood, bevel 8 in., lapped .................................... 1/2 in. 10 in., lapped .................................. 3/4 in. Wood, plywood, 3/8 in., lapped .................. Aluminum, steel, or vinyl,h, i over sheathing hollow-backed .......................................... insulating-board-backed ................ 3/8 in. foil-backed..................................... 3/8 in. Architectural (soda-lime float) glass ...........

— — —

— — —

0.81 1.05 0.59

— — — 158

— — — 6.9

0.62 1.82 2.96 —

0.28 0.28 0.29 — 0.29i 0.32 — 0.21

Building Membrane Vapor-permeable felt ..................................... Vapor: seal, 2 layers of mopped 15 lb felt ..... Vapor: seal, plastic film .................................

— — —

— — —

0.06 0.12 Negligible

— — —

Finish Flooring Materials Carpet and rebounded urethane pad.... 3/4 in. Carpet and rubber pad (one-piece)...... 3/8 in. Pile carpet with rubber pad ....... 3/8 to 1/2 in. Linoleum/cork tile............................... 1/4 in. PVC/rubber floor covering............................. rubber tile ......................................... 1.0 in. terrazzo............................................. 1.0 in.

7 20 18 29 — 119 —

— — — — 2.8 — —

2.38 0.68 1.59 0.51 — 0.34 0.08

— — — — — — 0.19

Metals (See Chapter 33, Table 3 in 2013 ASHRAE Handbook—Fundamentals)

180

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Table 12.8


Description Roofing Asbestos/cement shingles ............................... Asphalt (bitumen with inert fill) .....................

Plastering Materials Cement plaster, sand aggregate ...................... Sand aggregate.................................... 3/8 in. ......................................................... 3/4 in. Gypsum plaster ............................................... Lightweight aggregate ........................ 1/2 in. ......................................................... 5/8 in. on metal lath .................................... 3/4 in. Perlite aggregate ............................................. Sand aggregate................................................ on metal lath .................................... 3/4 in. Vermiculite aggregate.....................................

Perlite plaster .................................................. Pulpboard or paper plaster .............................. Sand/cement plaster, conditioned ................... Sand/cement/lime plaster, conditioned........... Sand/gypsum (3:1) plaster, conditioned ......... Masonry Materials Masonry units Brick, fired clay ..............................................

Clay tile, hollow 1 cell deep ............................................ 3 in. ........................................................... 4 in. 2 cells deep .......................................... 6 in. ........................................................... 8 in. ......................................................... 10 in. 3 cells deep ........................................ 12 in. Lightweight brick ........................................... Concrete blocksf, g Limestone aggregate 8 in., 36 lb, 138 lb/ft3 concrete, 2 cores ....... with perlite-filled cores................................ 12 in., 55 lb, 138 lb/ft3 concrete, 2 cores ..... with perlite-filled cores................................




120 100 119 144 70 70 70 59 17 141 — 15 —

— 2.98 4.0 7.97 — — — 1.32 0.62 8.32 — 0.49 —

0.21 — — — 0.15 0.44 0.33 — — — 0.05 — 0.94

0.24 — — — 0.36 0.3 0.35 — — — 0.3 — 0.31

116 — — 70 80 45 45 — 45 105 — 30 40 45 50 60 25 38 38 98 90 97

5.0 — — 2.63 3.19 — — — 1.5 5.6 — 1.0 1.39 1.7 1.8 2.08 0.55 1.32 0.48 4.4 3.33 4.5

— 0.08 0.15 — — 0.32 0.39 0.47 — — 0.13 — — — — — — — — — — —

0.2 0.2 0.2 — — — — — 0.32 0.2 — — — — — — — — — — — —

150 140 130 120 110 100 90 80 70

8.4 to 10.2 7.4 to 9.0 6.4 to 7.8 5.6 to 6.8 4.9 to 5.9 4.2 to 5.1 3.6 to 4.3 3.0 to 3.7 2.5 to 3.1

— — — — — — — — —

— — — 0.19 — — — — —

— — — — — — 50 48

— — — — — — 1.39 1.51

0.80 1.11 1.52 1.85 2.22 2.50 — —

0.21 — — — — — — —

— — — —

— —

— 2.1 — 3.7

— — — —

—


Asphalt roll roofing ........................................ Asphalt shingles.............................................. Built-up roofing .................................. 3/8 in. Mastic asphalt (heavy, 20% grit) .................... Reed thatch ..................................................... Roofing felt..................................................... Slate .................................................... 1/2 in. Straw thatch .................................................... Wood shingles, plain and plastic-film-faced ..

Density, lb/ft3

181

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Table 12.8



Description

Density, lb/ft3


Normal-weight aggregate (sand and gravel) 8 in., 33 to 36 lb, 126 to 136 lb/ft3 concrete, 2 or 3 cores ............................................... — — with perlite-filled cores ............................... — — with vermiculite-filled cores ....................... — — 12 in., 50 lb, 125 lb/ft3 concrete, 2 cores .... — — Medium-weight aggregate (combinations of normal and lightweight aggregate) 8 in., 26 to 29 lb, 97 to 112 lb/ft3 concrete, 2 or 3 cores ............................................... — — with perlite-filled cores ............................... — — with vermiculite-filled cores ....................... — — with molded-EPS-filled (beads) cores ........ — — with molded EPS inserts in cores................ — — Lightweight aggregate (expanded shale, clay, slate or slag, pumice) 3 6 in., 16 to 17 lb, 85 to 87 lb/ft concrete, 2 or 3 cores ............................................... — — with perlite-filled cores ............................... — — with vermiculite-filled cores .................... — — 8 in., 19 to 22 lb, 72 to 86 lb/ft3 concrete.... — — with perlite-filled cores ............................... — — with vermiculite-filled cores ....................... — — with molded-EPS-filled (beads) cores ........ — — with UF foam-filled cores ........................... — — with molded EPS inserts in cores................ — — 3 12 in., 32 to 36 lb, 80 to 90 lb/ft , concrete, 2 or 3 cores ............................................... — — with perlite-filled cores ............................... — — with vermiculite-filled cores ....................... — — Stone, lime, or sand........................................ 180 72 Quartzitic and sandstone ................................ 160 43 140 24 120 13 Calcitic, dolomitic, limestone, marble, and granite.......................................................... 180 30 160 22 140 16 120 11 100 8 Gypsum partition tile 3 by 12 by 30 in., solid................................ — — 4 cells .......................................................... — — 4 by 12 by 30 in., 3 cells ............................. — — Limestone....................................................... 150 3.95 163 6.45 Concretesi Sand and gravel or stone aggregate concretes (concretes with >50% quartz or quartzite sand have conductivities in higher end of range) Lightweight aggregate or limestone concretes expanded shale, clay, or slate; expanded slags; cinders; pumice (with density up to 100 lb/ft3); scoria (sanded concretes have conductivities in higher end of range) Gypsum/fiber concrete (87.5% gypsum, 12.5% wood chips)...................................... Cement/lime, mortar, and stucco ...................



1.11 to 0.97 2.0 1.92 to 1.37 1.23

0.22 — — 0.22

1.71 to 1.28 3.7 to 2.3 3.3 3.2 2.7

— — — — —

1.93 to 1.65 4.2 3.0 3.2 to 1.90 6.8 to 4.4 5.3 to 3.9 4.8 4.5 3.5

— — — 0.21 — — — — —

2.6 to 2.3 9.2 to 6.3 5.8 — — — —

— — — — — — 0.19

— — — — —

— — — 0.19 —

1.26 1.35 1.67 — —

0.19 — — 0.2 0.2

150 140

10.0 to 20.0 9.0 to 18.0

— —

— 0.19 to 0.24

130 120

7.0 to 13.0 6.4 to 9.1

— —

— —

100

4.7 to 6.2

—

0.2

80 60 40

3.3 to 4.1 2.1 to 2.5 1.3

— — —

0.2 — —

51 120 100 80

1.66 9.7 6.7 4.5

— — — —

0.2 — — —

182

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Table 12.8


Description Perlite, vermiculite, and polystyrene beads ....

Foam concretes ...............................................

Foam concretes and cellular concretes ...........

Polymer cement .............................................. Slag concrete...................................................

Woods (12% moisture content)j Hardwoods Oak............................................................... Birch ............................................................ Maple ........................................................... Ash ............................................................... Softwoods Southern pine ............................................... Southern yellow pine ................................... Eastern white pine........................................ Douglas fir/larch .......................................... Southern cypress .......................................... Hem/fir, spruce/pine/fir ............................... Spruce .......................................................... Western red cedar ........................................ West coast woods, cedars ............................ Eastern white cedar...................................... California redwood ...................................... Pine (oven-dried) ......................................... Spruce (oven-dried) .....................................




50 40 30 20 120 100 80 70 60 40 20 27 to 50 16 to 50 122 138 117 60 80 100 125

1.8 to 1.9 1.4 to 1.5 1.1 0.8 5.4 4.1 3.0 2.5 2.1 1.4 0.8 1.4 2.54 11.4 7.14 5.39 1.5 2.25 3 8.53

— — — — — — — — — — — — — — — — — — — —

— 0.15 to 0.23 — — — — — — — — — 0.2 0.2 — — — — — — —

— 41 to 47 43 to 45 40 to 44 38 to 42 — 36 to 41 31 25 34 to 36 31 to 32 24 to 31 25 22 22 to 31 23 24 to 28 23 25

— 1.12 to 1.25 1.16 to 1.22 1.09 to 1.19 1.06 to 1.14 — 1.00 to 1.12 1.06 to 1.16 0.85 to 0.94 0.95 to 1.01 0.90 to 0.92 0.74 to 0.90 0.74 to 0.85 0.83 to 0.86 0.68 to 0.90 0.82 to 0.89 0.74 to 0.82 0.64 0.69

— — — — — — — — — — — — — — — — — — —

0.39k — — — — 0.39 k — — — — — — — — — — — 0.45 0.45


Aerated concrete (oven-dried) ........................ Polystyrene concrete (oven-dried).................. Polymer concrete ............................................

Density, lb/ft3

183

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Notes for Table 12.8


a

Values are for mean temperature of 75°F. Representative values for dry materials are intended as design (not specification) values for materials in normal use. Thermal values of insulating materials may differ from design values depending on in-situ properties (e.g., density and moisture content, orientation, etc.) and manufacturing variability. For properties of specific product, use values supplied by manufacturer or unbiased tests. b Symbol  also used to represent thermal conductivity. c Does not include paper backing and facing, if any. Where insulation forms boundary (reflective or otherwise) of airspace, see Tables 2 and 3 for insulating value of airspace with appropriate effective emittance and temperature conditions of space. d Conductivity varies with fiber diameter (see Chapter 25). Batt, blanket, and loose-fill mineral fiber insulations are manufactured to achieve specified R-values, the most common of which are listed in the table. Because of differences in manufacturing processes and materials, the product thicknesses, densities, and thermal conductivities vary over considerable ranges for a specified R-value. e Insulating values of acoustical tile vary, depending on density of board and on type, size, and depth of perforations. f Values for fully grouted block may be approximated using values for concrete with similar unit density. g Values for concrete block and concrete are at moisture contents representative of normal use. h Values for metal or vinyl siding applied over flat surfaces vary widely, depending on ventilation of the airspace beneath the siding; whether airspace is reflective or nonreflective; and on thickness, type, and application of insulating backing-board used. Values are averages for use as design guides, and were obtained from several guarded hot box tests (ASTM Standard C1363) on hollow-backed types and types made using backing of wood fiber, foamed plastic, and glass fiber. Departures of ±50% or more from these values may occur. i Vinyl specific heat = 0.25 Btu/lb·°F. j See Adams (1971), MacLean (1941), and Wilkes (1979). Conductivity values listed are for heat transfer across the grain. Thermal conductivity of wood varies linearly with density, and density ranges listed are those normally found for wood species given. If density of wood species is not known, use mean conductivity value. For extrapolation to other moisture contents, the following empirical equation developed by Wilkes (1979) may be used: –2

–4

 1.874  10 + 5.753  10 M  k = 0.1791 + ----------------------------------------------------------------------------------1 + 0.01M where  is density of moist wood in lb/ft3, and M is moisture content in percent. k From Wilkes (1979), an empirical equation for specific heat of moist wood at 75°F is as follows:  0.299 + 0.01 M  c p = ----------------------------------------- + c p  1 + 0.01 M  where cp accounts for heat of sorption and is denoted by c p = M  1.921  10

–3

–5

– 3.168  10 M 

where M is moisture content in percent by mass.

184

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Cooling Load Temperature Differences (CLTDs) Table 12.9

Roof No 1 2 3 4 5 8 9 10 13 14

4 –5 –4 2 3 8 17 16 22 25 27

6 –6 –6 –2 –2 3 11 9 15 20 23

Table 12.10

Roof No.

2 –2 0 8 11 16 25 26 32 31 32

1 2 3 4 5 8 9 10 13 14

4 –5 –4 2 3 8 17 16 23 25 28

6 –6 –6 –2 –1 3 12 9 15 20 23

Table 12.11

Roof No. 1 2 3 4 5 8 9 10 13 14

2 –2 0 8 12 16 24 26 31 30 32

4 –5 –4 2 3 8 17 16 22 25 27

6 –5 –5 –1 –1 3 11 9 15 20 23

8 9 1 3 –4 1 9 4 9 16 19

10 44 30 22 5 10 14 5 8 16 19

Solar time, h 12 14 76 92 64 86 47 68 27 55 30 52 27 43 17 36 16 30 23 33 24 32

16 86 89 77 75 68 54 54 45 43 40

18 58 70 68 80 70 58 65 56 49 45

20 23 36 47 67 59 52 63 59 49 45

22 8 14 29 43 41 42 51 52 43 42

24 2 5 16 23 27 32 37 41 37 37

22 9 15 30 45 42 43 52 52 44 42

24 2 5 17 24 27 33 38 42 37 37

22 9 16 30 45 42 42 51 51 43 41

24 2 5 17 25 27 32 38 41 37 36

CLTDs for Flat Roofs—36°N Latitude, July

8 12 4 4 –3 2 9 4 10 16 20

10 45 32 24 7 12 15 7 9 17 20

Solar time, h 12 14 75 90 63 84 47 67 29 55 31 52 28 42 19 37 17 30 24 33 25 32

16 84 87 75 74 67 54 54 45 43 40

18 60 70 68 79 70 58 64 56 49 45

20 26 39 48 67 59 53 63 58 49 46


2 –2 0 8 11 16 24 25 31 31 32



8 15 6 6 –2 3 10 5 10 16 20

10 44 32 24 8 13 16 8 10 18 20

Solar time, h 12 14 69 83 60 78 45 63 29 52 31 49 27 40 19 35 17 29 24 32 24 31

16 79 81 71 69 63 51 51 43 41 38

18 59 68 65 74 66 55 60 53 47 43

20 29 41 48 65 58 51 61 56 47 44

CAUTION: Approximate data—Use for preliminary computations only. Also, see notes on next page.

185

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Notes for CLTD Data for Flat Roofs 1. Data apply directly to (1) dark surface, (2) indoor temperature is 78°F, (3) outdoor maximum temperature of 95°F with mean temperature of 85°F and daily range of 21°F, (4) solar radiation typical of clear day on 21st day of month, (5) outside surface film resistance of 0.333 h·ft2 ·°F/Btu, and (6) inside surface resistance of 0.685 h·ft2 ·°F/Btu. 2. Adjustments to design temperatures Corr. CLTD = CLTD + (78  tr) + (tm  85)


where tr = inside temperature and tm = mean outdoor temperature, or tm = maximum outdoor temperature  (daily range)/2. No adjustment recommended for color or for ventilation of air space above a ceiling. For design purposes, the data suffice for plus or minus 2 weeks from the 21st day of given month. Table 12.12

Mass Location

Roof Classifications for Use with CLTD Tables for Flat Roofs

Suspended R, Ceiling h·ft2 ·°F/Btu

Without Mass inside insul. With

Without Mass evenly placed With

Without Mass outside insul. With

0 to 10 10 to 20 20 to 25 0 to 5 5 to 10 10 to 20 20 to 25 0 to 5 5 to 15 15 to 25 0 to 5 5 to 10 10 to 15 15 to 20 20 to 25 0 to 5 5 to 10 10 to 15 15 to 25 0 to 10 10 to 15 15 to 20

Wood 1 in.

2 in. (Heavyweight) Concrete

Steel Deck

* * * * * * * 1 2 4 * 4 5 9 10 * * * * * * *

2 4 5 5 8 13 14 2 * * 3 * * * * 2 3 4 5 3 4 5

* * * * * * * 1 1 2 1 1 2 2 4 * * * * * * *

Attic Ceiling Comb. * * * * * * * 1 2 2 * * * * * * * * * * *

*Denotes roof that is not possible with the chosen parameters

186

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Table 12.13

Approximate CLTDs for Sunlit Walls—24°N Latitude, July

Solar time, h 8 10 12 14 16 18 20 6

Wall Facing 6

Low Mass, Low R-Value Wall

–2 0 0 –2 –3 –3 –3 –3

13 39 44 25 3 3 3 3

18 53 63 44 12 13 13 13

22 39 48 42 24 22 22 22

28 30 32 32 31 40 42 37

32 30 30 30 30 58 73 62

34 24 24 24 23 52 75 67

17 13 13 13 13 20 27 25

N NE E SE S SW W NW

3 3 7 12 16 21 25 27 3 6 20 31 33 32 31 27 4 6 22 36 39 36 33 29 3 4 14 25 30 30 30 26 3 1 3 7 14 20 23 22 5 3 4 8 14 26 38 40 7 4 4 8 15 28 45 51 6 3 4 8 14 25 40 46

Low Mass, Medium R-Value Wall

1 0 1 0 0 1 2 1

0 3 3 1 –1 –1 0 0

6 20 22 13 1 1 2 2

13 36 43 28 7 7 7 7

18 39 46 35 16 15 15 15

23 35 40 35 24 29 30 27

28 32 34 32 27 43 52 45

30 27 28 27 25 47 61 54

Solar time, h 8 10 12 14 16 18 20

Low Mass, High R-Value Wall

–2 –2 –2 –2 –2 –2 –1 –1

2 9 10 4 –1 –1 –1 –1

12 36 42 26 4 5 5 5

18 46 55 40 13 13 13 13

23 38 44 38 24 24 23 22

28 32 35 33 29 42 46 40

32 29 30 29 28 54 69 60

29 22 23 22 22 44 61 55

High Mass, Low R-Value Wall High Mass, Medium R-Value Wall High Mass, High R-Value Wall

10 11 12 10 8 13 17 15

8 9 10 8 6 10 13 12

8 14 15 11 5 9 11 10

10 21 24 17 6 9 11 10

12 25 29 21 10 11 13 12

15 26 30 24 14 17 18 17

18 27 30 25 17 24 28 25

21 26 29 25 18 30 36 32

12 13 14 13 10 17 21 19

9 10 11 10 8 13 16 14

8 10 11 9 6 10 12 11

8 15 17 12 5 8 10 9

10 21 24 17 7 9 11 10

13 24 28 21 10 12 13 12

16 27 30 24 14 18 20 18

19 27 31 25 17 25 30 26


N NE E SE S SW W NW

Solar time, h 8 10 12 14 16 18 20 6

CAUTION: Approximate data—Use for preliminary computations only.

Table 12.14

Approximate CLTDs for Sunlit Walls—36°N Latitude, July

Solar time, h Solar time, h Solar time, h Wall Facing 6 8 10 12 14 16 18 20 6 8 10 12 14 16 18 20 6 8 10 12 14 16 18 20 Low Mass, Low R-Value Wall

N NE E SE S SW W NW

–1 1 1 –1 –3 –2 –2 –2

N NE E SE S SW W NW

3 3 4 4 3 6 7 6

12 41 49 31 4 4 4 4

14 46 64 52 18 13 13 13

21 30 48 52 39 23 21 21

28 29 31 36 47 50 42 29

29 29 30 30 40 67 73 53

30 24 24 24 25 59 78 65

17 14 14 14 14 23 31 28


0 0 1 1 0 1 2 1

0 4 4 2 –1 0 0 0

5 21 26 16 2 2 2 2

10 33 45 34 11 8 8 8

16 33 47 44 25 17 15 15

22 31 40 41 36 34 30 24

26 30 34 35 38 51 52 39

27 27 29 29 32 54 63 51


–2 –2 –2 –2 –2 –1 –1 –2

3 12 14 7 –1 –1 –1 –1

9 36 46 31 6 5 5 5

15 39 56 48 21 13 13 13

21 32 45 47 37 28 23 21

27 30 34 37 44 50 46 33

28 28 30 31 37 62 69 53

27 23 23 23 25 51 65 55


3 7 8 5 2 3 4 3

6 20 25 17 4 4 5 4

10 28 38 30 11 8 9 8

15 29 40 37 22 16 15 14

20 29 37 36 31 31 28 22

23 29 34 33 33 44 46 35

25 26 29 29 29 46 54 43

9 10 12 12 10 15 17 14

7 9 11 10 8 12 14 11

8 14 17 13 7 10 12 10

9 20 25 20 9 10 11 10

11 23 30 26 14 13 13 12

14 24 31 29 20 19 18 15

17 25 31 29 24 28 28 22

19 25 30 28 25 34 37 30

11 13 15 14 13 19 22 18

9 10 11 11 10 15 17 14

7 10 12 10 7 11 13 11

7 15 18 14 7 10 11 9

9 19 25 20 10 10 11 10

11 22 30 26 15 14 14 12

14 24 31 29 21 21 20 17

17 25 31 30 24 29 30 24

CAUTION: Approximate data—Use for preliminary computations only.

187

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Table 12.15 Approximate CLTDs for Sunlit Walls—48°N Latitude, July CAUTION: Approximate data—Use for preliminary computations only.

Solar time, h Solar time, h Solar time, h Wall Facing 6 8 10 12 14 16 18 20 6 8 10 12 14 16 18 20 6 8 10 12 14 16 18 20


Low Mass, Low R-Value Wall

N NE E SE S SW W NW

3 10 10 4 –2 –1 –1 –2

N NE E SE S SW W NW

3 4 4 4 5 7 8 6

10 42 54 36 5 5 5 5

13 38 64 59 28 12 13 12

21 26 47 61 52 29 21 21

27 28 31 45 62 59 41 27

28 29 29 31 51 75 72 45

27 24 25 25 29 65 80 62

21 15 15 15 15 29 41 37


1 1 1 1 1 2 2 2

2 7 8 4 0 0 0 0

6 23 30 20 3 3 3 2

10 31 47 40 16 8 8 8

16 30 48 51 34 20 15 14

21 29 40 49 48 40 29 22

25 28 34 40 50 58 51 34

26 26 29 32 40 61 64 47


–1 0 0 –1 –1 –1 –1 –1

5 18 20 11 0 0 0 0

9 36 49 36 9 6 6 5

14 34 57 55 30 14 13 13

21 28 44 56 50 33 22 20

26 28 34 43 57 58 45 29

27 28 29 33 47 69 69 46

27 23 23 24 30 57 69 54


4 10 11 7 3 4 5 4

6 22 28 20 6 5 6 5

10 26 40 35 16 9 9 8

14 26 40 43 31 19 15 14

19 27 37 42 41 36 27 20

22 27 34 38 43 50 45 31

24 25 29 32 37 52 55 41

9 10 12 13 13 18 19 14

8 10 12 12 10 14 15 11

8 15 19 15 9 12 12 10

9 20 27 23 12 12 12 10

11 22 32 30 19 15 14 12

14 23 32 34 27 23 19 15

17 24 32 34 32 32 28 20

19 24 30 32 33 39 38 28

12 13 15 16 16 22 23 18

9 10 12 12 12 17 18 14

8 12 14 12 10 13 14 11

8 16 20 17 10 11 12 9

9 19 27 24 14 12 12 10

11 22 31 30 21 16 14 12

14 23 32 34 28 24 20 16

17 24 32 34 32 33 30 22

Note 1. Apply data directly to (1) dark surface, (2) indoor temperature of 78°F, (3) outdoor maximum temperature of 95°F with mean temperature of 85°F and daily range of 21°F, (4) outside surface film resistance of 0.333 (h·ft2·°F)/Btu, and (5) inside surface resistance of 0.685 (h·ft2·°F)/Btu. Note 2. Adjustments to design temperatures: Corr. CLTD = CLTD + (78  tr) + (tm  85) where tr = inside temperature and tm = mean outdoor temperature, or tm = maximum outdoor temperature  (daily range)/2 Note 3. Adjustments to months other than July: For design purposes, the data suffice for plus or minus 2 weeks from the 21st day of given month.

188

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Table 12.16 Solar Cooling Load for Sunlit Glass (SCL) Tables do not consider zone type and are conservative. Use for preliminary computations only.

Glass Facing 5

6

7

8

9

10

0 0 0 0 0 0 0 0 0

19 54 57 26 5 5 5 5 10

35 124 139 74 15 15 15 15 55

36 150 177 104 23 23 23 23 113

36 144 180 114 30 30 30 30 170

38 115 154 106 35 35 35 35 218

N NE E SE S SW W NW Hor

0 0 0 0 0 0 0 0 0

25 79 86 42 8 8 8 8 20

29 129 153 90 17 17 17 17 66

28 139 184 125 24 24 24 24 120

32 120 182 142 36 30 30 30 171

36 84 155 140 53 35 35 35 215


14 32 31 11 3 3 3 3 5

28 101 112 58 11 11 11 11 32

24 130 165 106 18 18 18 18 73

27 126 188 143 30 24 24 24 120

31 95 182 164 58 30 30 30 163

34 61 153 168 90 34 34 34 200

16

17

18

19 20 21 22

39 32 33 32 32 118 186 151 176

43 25 25 25 24 105 184 158 115

32 14 14 14 14 62 118 106 54

11 6 6 6 6 24 44 39 24

6 3 1 3 1 1 3 1 1 3 1 1 3 1 1 12 6 3 21 11 5 19 9 5 12 6 3

32 32 33 34 38 144 188 129 178

33 26 26 27 29 127 191 148 124

36 17 17 17 18 85 149 127 66

12 7 7 7 7 32 53 43 28

6 3 1 3 2 1 3 2 1 3 2 1 3 2 1 15 8 4 25 12 6 21 10 5 13 7 3

31 31 32 35 56 166 186 106 170

27 26 27 28 37 146 193 134 125

34 19 19 20 24 106 167 134 76

25 10 10 10 12 50 89 76 35

9 4 2 4 2 1 4 2 1 4 2 1 5 3 1 22 11 5 36 17 9 30 14 7 16 8 4



Solar time, h 11 12 13 14 15 24°N Latitude, July 40 42 42 40 38 78 58 49 44 38 107 68 54 46 40 83 59 50 44 38 40 43 43 40 37 39 42 61 88 110 39 41 67 116 160 39 41 51 83 122 253 271 273 258 225 36°N Latitude, July 39 40 41 39 36 58 50 45 41 37 107 67 54 45 39 119 86 58 48 40 70 80 79 68 52 38 57 90 122 141 38 40 66 115 159 38 40 40 56 93 246 263 265 251 221 48°N Latitude, July 37 38 38 37 35 49 44 41 38 35 104 65 51 43 38 152 119 77 54 43 116 130 130 116 88 46 82 122 152 168 36 38 64 112 156 36 38 38 40 67 226 241 242 230 205

Tables do not consider zone type and are conservation. Data apply directly to: (1) standard double strength glass with no inside shade, and (2) clear sky, 21st day of month. Adjustments to table data: • Latitudes other than 24, 36 and 48°N Linear interpolation is acceptable. • Months other than July For design purposes, data will suffice for plus or minus 2 weeks from the 21st day of given month. • Other types of glass and internal shade Use shading coefficients as multiplier. • Externally shaded glass Use north orientation.

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12_AirCondLoadData.fm Page 190 Tuesday, October 7, 2014 2:14 PM © 2013 ASHRAE (www.ashrae.org). For personal use only. Additional reproduction, distribution, or transmission in either print or digital form is not permitted without ASHRAE's prior written permission. *

Table 12.17

Shading Coefficients for Single Glass with Indoor Shading by Venetian Blinds or Roller Shades

Type of Glass

Clear

Nominal Thickness,a in.

3/32c

Type of Shading Roller Shade TransOpaque lucent Medium Light Dark White Light

Solar Transmit- Venetian Blinds tanceb 0.87 to 0.80

0.74d


(0.63) Clear

1/4 to 1/2

Clear pattern

1/8 to 1/2

Heat-absorbing pattern Tinted Heat-absorbingf Heat-absorbing pattern Tinted Heat-absorbing or pattern

1/8 3/16, 7/32 3/16, 1/4 3/16, 1/4 1/8, 7/32

Heat-absorbingf Heat-absorbing or pattern

— 3/8

— Reflective coated glass S.C. = 0.30g = 0.40 = 0.50 = 0.60

0.80 to 0.71 0.87 to 0.79 — 0.74, 0.71 0.46 — 0.59, 0.45 0.44 to 0.30 0.34 0.29 to 0.15 0.24

e

0.67d

0.81

0.39

0.44

(0.58)e

0.57

0.53

0.45

0.30

0.36

0.54

0.52

0.40

0.28

0.32

0.42 0.25 0.33 0.42 0.50

0.40 0.23 0.29 0.38 0.44

0.36

0.28

0.31

a

Refer to manufacturers’ literature for values. For vertical blinds with opaque white and beige louvers in the tightly closed position, SC is 0.25 and 0.29 when used with glass of 0.71 to 0.80 transmittance. Typical residential glass thickness. d From Van Dyck and Konen (1982), for 45° open venetian blinds, 35° solar incidence, and 35° profile angle. e Values for closed venetian blinds. Use these values only when operation is automated for solar gain reduction (as opposed to daylight use). f Refers to gray, bronze, and green tinted heat-absorbing glass. g SC for glass with no shading device. b c

*

Note: Shading Coefficient (SC) has been superseded by solar heat gain coefficient (SHGC) including the effect of incident angle of solar radiation on the glass, and the effect of type of framing. This shading coefficient table is sufficiently accurate for the approximate cooling load calculations of this publication. For the glazing portion of single-pane clear and tinted fenestration, SC = SHGC/0.87. This does not include frame effects.

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Theater, night Offices, hotels, apartments Offices, hotels, apartments Department store; retail store Drug store, bank Restaurantc Factory Dance hall Factory Bowling alley Factory Factory Gymnasium

Theater, matinee

Location

Total Heat, Btu/h Adult Adjusted, Male M/F a 390 330 390 350 450 400 475 450 550 450 550 500 490 550 800 750 900 850 1000 1000 1500 1450 1500 1450 1600 1600 2000 1800 245 245 250 250 250 275 275 305 375 580 580 635 710

225

Sensible Heat, Btu/h 105 155 200 200 250 275 475 545 625 870 870 965 1090

105

Latent Heat, Btu/h


27

38

35

19

60

58

49

54

% Sensible Heat that is Radiantb Low V High V

Notes: 1. Tabulated values are based on 75°F room dry-bulb temperature. For 80°F room dry bulb, total heat remains the same, but sensible heat values should be decreased by approximately 20%, and latent heat values increased accordingly. 2. Also see Table 4, Chapter 9, for additional rates of metabolic heat generation. 3. All values are rounded to nearest 5 Btu/h. a Adjusted heat gain is based on normal percentage of men, women, and children for the application listed, and assumes that gain from an adult female is 85% of that for an adult male, and gain from a child is 75% of that for an adult male. b Values approximated from data in Table 6, Chapter 9, where V is air velocity with limits shown in that table. c Adjusted heat gain includes 60 Btu/h for food per individual (30 Btu/h sensible and 30 Btu/h latent). d Figure one person per alley actually bowling, and all others as sitting (400 Btu/h) or standing or walking slowly (550 Btu/h).

Seated at theater Seated at theater, night Seated, very light work Moderately active office work Standing, light work; walking Walking, standing Sedentary work Light bench work Moderate dancing Walking 3 mph; light machine work Bowlingd Heavy work Heavy machine work; lifting Athletics

Degree of Activity

Table 12.18 Representative Rates at Which Heat and Moisture are Given Off by Human Beings in Different States of Activity [2013F, Ch 18, Tbl 1]



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Heat Gain from Lighting The energy absorbed by the structure and contents contributes to space cooling load only after a time lag, some still reradiating after the heat sources have been switched off. This may make load lower than instantaneous heat gain, thus affecting the peak load. Instantaneous rate of heat gain from lights, qel Btu/h: qel = 3.41 WFulFsa


where W Ful Fsa 3.41

= = = =

total lights wattage installed lighting use factor (proportion in use) lighting special allowance factor conversion factor

The total light wattage is obtained from the ratings of all lamps installed, both for general illumination and for display use. Ballasts are not included, but are addressed by a separate factor. Wattages of magnetic ballasts are significant; the energy consumption of high-efficiency electronic ballasts might be insignificant compared to that of the lamps. The lighting use factor is the ratio of wattage in use, for the conditions under which the load estimate is being made, to total installed wattage. For commercial applications such as stores, the use factor is generally 1.0. The special allowance factor is the ratio of the lighting fixtures’ power consumption, including lamps and ballast, to the nominal power consumption of the lamps. For incandescent lights, this factor is 1. For fluorescent lights, it accounts for power consumed by the ballast as well as the ballast’s effect on lamp power consumption. The special allowance factor can be less than 1 for electronic ballasts that lower electricity consumption below the lamp’s rated power consumption. Use manufacturers’ values for system (lamps + ballast) power, when available. For high-intensity-discharge lamps (e.g. metal halide, mercury vapor, high- and low-pressure sodium vapor lamps), the actual lighting system power consumption should be available from the manufacturer of the fixture or ballast. Ballasts available for metal halide and high pressure sodium vapor lamps may have special allowance factors from about 1.3 (for low-wattage lamps) down to 1.1 (for high-wattage lamps). An alternative procedure is to estimate the lighting heat gain on a per square foot basis. Such an approach may be required when final lighting plans are not available. Table 12.19 shows the maximum lighting power density (LPD) (lighting heat gain per square foot) allowed by ASHRAE Standard 90.1-2010 for a range of space types.

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Table 12.19

Lighting Power Densities Using Space-by-Space Method [Std 90.1-2010, Tbl 9.6.1]

Common Space Types*

LPD, Building-Specific Space Types W/ft2 1.1 Gymnasium/exercise center 1.1 Playing Area 1.3 1.4 1.3 1.3 1.1 3.3 1.1 0.9 0.4 0.3 0.7 0.7 1.7 0.4 2.6 1.2 0.5 0.6 0.2 1.2 0.8 0.9 1.3 1.3 1.2 1.4 2.1 1.2 1.4 0.9 0.6 0.5 1.0 0.5 0.6 0.8 0.9 0.3 0.8 1.5 1.9 1.7

Exercise Area Courthouse/police station/penitentiary Courtroom Confinement cells Judges’ chambers Fire Stations Engine room Sleeping quarters Post office—sorting area Convention center—exhibit space Library Card file and cataloging Stacks Reading area Hospital Emergency Recovery Nurses’ station Exam/treatment Pharmacy Patient room Operating room Nursery Medical supply Physical therapy Radiology Laundry—washing Automotive—service/repair Manufacturing Low bay (<25 ft floor to ceiling height) High bay (25 ft floor to ceiling height) Detailed manufacturing Equipment room Control room Hotel/motel guest rooms Dormitory—living quarters Museum General exhibition Restoration Bank/office—banking activity area Religious buildings Worship pulpit, choir Fellowship hall Retail

LPD, W/ft2 1.4 0.9 1.9 0.9 1.3 0.8 0.3 1.2 1.3 1.1 1.7 1.2


Office—enclosed Office—open plan Conference/meeting/ multipurpose Classroom/lecture/training For penitentiary Lobby For hotel For performing arts theater For motion picture theater Audience/seating area For gymnasium For exercise center For convention center For penitentiary For religious buildings For sports arena For performing arts theater For motion picture theater For transportation Atrium—first three floors Atrium—each additional floor Lounge/recreation For hospital Dining Area For penitentiary For hotel For motel For bar lounge/leisure dining For family dining Food preparation Laboratory Restrooms Dressing/locker/fitting room Corridor/transition For hospital For manufacturing facility Stairs—active Active storage For hospital Inactive storage For museum Electrical/mechanical Workshop Sales area [for accent lighting, see Section 9.6.2(B) of ASHRAE Standard 90.1]

2.7 0.8 1.0 1.5 1.2 0.7 2.2 0.6 1.4 0.9 0.4 0.6 0.7 1.2 1.7 2.1 1.2 0.5 1.1 1.1 1.0 1.7 1.5 2.4 0.9

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Table 12.19

Lighting Power Densities Using Space-by-Space Method [Std 90.1-2010, Tbl 9.6.1] (Continued)


Common Space Types*

LPD, W/ft2

Building-Specific Space Types Sales area [for accent lighting, see Section 9.6.3(C) of ASHRAE Standard 90.1] Mall concourse Sports arena Ring sports area Court sports area Indoor playing field area Warehouse Fine material storage Medium/bulky material storage Parking garage—garage area Transportation Airport—concourse Air/train/bus—baggage area Terminal—ticket counter

LPD, W/ft2 1.7 1.7 2.7 2.3 1.4 1.4 0.9 0.2 0.6 1.0 1.5

*In cases where both a common space type and a building-specific type are listed, the building-specific space type applies.

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Table 12.20 provides a range of design data under typical operating conditions: airflow 1 cfm/ft2, supply air between 59°F and 62°F, room temperature between 72°F and 75°F, and lighting heat input in a range from 0.9 to 2.6 W/ft2. For a fluorescent luminaire without lens, Figure 12.1 gives more precise data. The data should be used with judgment. Table 12.20 Lighting Heat Gain Parameters for Typical Operating Conditions [2013F, Ch 18, Tbl 3]

Luminaire Category

Space Fraction

0.64 to 0.74

Recessed fluorescent luminaire with lens

0.40 to 0.50

Downlight compact fluorescent luminaire

0.12 to 0.24

Downlight 0.70 to 0.80 incandescent luminaire

Non-in-ceiling fluorescent luminaire

1.0

Notes

• Use middle values in most situations • May use higher space fraction, and lower radiative fraction for luminaire with side-slot returns 0.48 to 0.68 • May use lower values of both fractions for direct/indirect luminaire • May use higher values of both fractions for ducted returns • May adjust values in the same way as 0.61 to 0.73 for recessed fluorescent luminaire without lens • Use middle or high values if detailed features are unknown 0.95 to 1.0 • Use low value for space fraction and high value for radiative fraction if there are large holes in luminaire’s reflector • Use middle values if lamp type is unknown • Use low value for space fraction if 0.95 to 1.0 standard lamp (i.e. A-lamp) is used • Use high value for space fraction if reflector lamp (i.e. BR-lamp) is used • Use lower value for radiative fraction for surface-mounted luminaire 0.5 to 0.57 • Use higher value for radiative fraction for pendant luminaire


Recessed fluorescent luminaire without lens

Radiative Fraction

Source: Fisher and Chantrasrisalai (2006).

Figure 12.1

Lighting Heat Gain Parameters for Recessed Fluorescent Luminaire Without Lens [2013F, Ch 18, Fig 3] 195

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Heat Gain from Motors and their Loads Instantaneous rate of heat gain from equipment operated by electric motors within a conditioned space. qem = 2545 (P/EM) FUM FLM


where qem P EM FUM FLM

= = = = =

heat equivalent of equipment operation, Btu/h motor power rating, hp motor efficiency, decimal fraction < 1.0 motor use factor 1.0 or <1.0 (proportion operating) motor load factor 1.0 or <1.0

When motor is outside the conditioned space, but load is inside, qem = 2545 P FUM FLM When motor is inside the conditioned space, but load is outside,  1.0 – E 

M - FUM FLM qem = 2545 P  --------------------- 

EM



Heat output of a motor is generally proportional to motor load, within rated overload limits. Because of typically high no-load motor current, fixed losses, and other reasons, FLM is generally assumed to be unity, and no adjustment should be made for underloading or overloading unless the situation is fixed and can be accurately established, and reduced-load efficiency data can be obtained from the motor manufacturer. Unless the manufacturer’s technical literature indicates otherwise, motor heat gain normally should be equally divided between radiant and convective components for the subsequent cooling load calculations.

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Table 12.21 Minimum Nominal Full-Load Efficiency for 60 HZ NEMA General Purpose Electric Motors (Subtype I) Rated 600 Volts or Less (Random Wound)* [2013F, Ch 18, Tbl 4]


Minimum Nominal Full Load Efficiency (%) for Motors Manufactured on or after December 19, 2010 Totally Enclosed Open Drip-Proof Motors Fan-Cooled Motors Number of Poles  2 4 6 2 4 6 Synchronous Speed (RPM)  3600 1800 1200 3600 1800 1200 Motor Horsepower 1 77.0 85.5 82.5 77.0 85.5 82.5 1.5 84.0 86.5 86.5 84.0 86.5 87.5 2 85.5 86.5 87.5 85.5 86.5 88.5 3 85.5 89.5 88.5 86.5 89.5 89.5 5 86.5 89.5 89.5 88.5 89.5 89.5 7.5 88.5 91.0 90.2 89.5 91.7 91.0 10 89.5 91.7 91.7 90.2 91.7 91.0 15 90.2 93.0 91.7 91.0 92.4 91.7 20 91.0 93.0 92.4 91.0 93.0 91.7 25 91.7 93.6 93.0 91.7 93.6 93.0 30 91.7 94.1 93.6 91.7 93.6 93.0 40 92.4 94.1 94.1 92.4 94.1 94.1 50 93.0 94.5 94.1 93.0 94.5 94.1 60 93.6 95.0 94.5 93.6 95.0 94.5 75 93.6 95.0 94.5 93.6 95.4 94.5 100 93.6 95.4 95.0 94.1 95.4 95.0 125 94.1 95.4 95.0 95.0 95.4 95.0 150 94.1 95.8 95.4 95.0 95.8 95.8 200 95.0 95.8 95.4 95.4 96.2 95.8 250 95.0 95.8 95.4 95.8 96.2 95.8 300 95.4 95.8 95.4 95.8 96.2 95.8 350 95.4 95.8 95.4 95.8 96.2 95.8 400 95.8 95.8 95.8 95.8 96.2 95.8 450 95.8 96.2 96.2 95.8 96.2 95.8 500 95.8 96.2 96.2 95.8 96.2 95.8 Source: ASHRAE Standard 90.1-2010 *Nominal efficiencies established in accordance with NEMA Standard MG1. Design A and Design B are National Electric Manufacturers Association (NEMA) design class designations for fixed-frequency small and medium AC squirrel-cage induction motors.

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Cabinet: hot serving (large), insulated* hot serving (large), uninsulated proofing (large)* proofing (small 15-shelf) Coffee brewing urn Drawer warmers, 2-drawer (moist holding)* Egg cooker Espresso machine* Food warmer: steam table (2-well-type) Freezer (small) Hot dog roller* Hot plate: single burner, high speed Hot-food case (dry holding)* Hot-food case (moist holding)* Microwave oven: commercial (heavy duty) Oven: countertop conveyorized bake/finishing* Panini* Popcorn popper*

Appliance

Energy Rate, Btu/h Rated Standby 6,800 1,200 6,800 3,500 17,400 1,400 14,300 3,900 13,000 1,200 4,100 500 10,900 700 8,200 1,200 5,100 3,500 2,700 1,100 3,400 2,400 3,800 3,000 31,100 2,500 31,100 3,300 10,900 0 20,500 12,600 5,800 3,200 2,000 200 Sensible Radiant 400 700 1,200 0 200 0 300 400 300 500 900 900 900 900 0 2,200 1,200 100

Rate of Heat Gain, Btu/h Sensible Latent Convective 800 0 2,800 0 0 200 900 3,000 300 700 0 200 400 0 800 0 600 2,600 600 0 1,500 0 2,100 0 1,600 0 1,800 600 0 0 10,400 0 2,000 0 100 0 1,200 3,500 1,400 3,900 1,200 200 700 1,200 3,500 1,100 2,400 3,000 2,500 3,300 0 12,600 3,200 200

Total

Table 12.22 Recommended Rates of Radiant and Convective Heat Gain from Unhooded Electric Appliances during Idle (Ready-to-Cook) Conditions [2013F, Ch 18, Tbl 5A]

Heat gain: qs = qinput FU FR, where FU is the usage factor and FR is the radiation factor.

Cooking Appliances


0.18 0.51 0.08 0.27 0.09 0.12 0.06 0.15 0.69 0.41 0.71 0.79 0.08 0.11 0.00 0.61 0.55 0.10

Usage Factor FU

0.33 0.20 0.86 0.00 0.17 0.00 0.43 0.33 0.09 0.45 0.38 0.30 0.36 0.27 0.00 0.17 0.38 0.50

Radiation Factor FR


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Rapid-cook oven (quartz-halogen)*

Sensible Radiant 0 1,000 300 600 600 200 2,700 3,000 400 800

Rate of Heat Gain, Btu/h Sensible Latent Convective 0 0 3,100 0 900 0 300 0 100 0 1,400 1,000 2,600 0 7,300 0 3,300 0 400 0

*Items with an asterisk appear only in Swierczyna et al. (2009); all others appear in both Swierczyna et al. (2008) and (2009).

Rapid-cook oven (microwave/convection)* Reach-in refrigerator* Refrigerated prep table* Steamer (bun) Toaster: 4-slice pop up (large): cooking contact (vertical) conveyor (large) small conveyor Waffle iron

Energy Rate, Btu/h Rated Standby 41,000 0 24,900 4,100 4,800 1,200 2,000 900 5,100 700 6,100 3,000 11,300 5,300 32,800 10,300 5,800 3,700 3,100 1,200 1,000 1,200 900 700 2,600 5,300 10,300 3,700 1,200

0

Total


Appliance

Table 12.22 Recommended Rates of Radiant and Convective Heat Gain from Unhooded Electric Appliances during Idle (Ready-to-Cook) Conditions [2013F, Ch 18, Tbl 5A] (Continued)


0.16 0.25 0.45 0.14 0.49 0.47 0.31 0.64 0.39

0.00

Usage Factor FU

0.24 0.25 0.67 0.86 0.07 0.51 0.29 0.11 0.67

0.00

Radiation Factor FR


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Table 12.23

Recommended Rates of Radiant Heat Gain from Hooded Electric Appliances during Idle (Ready-to-Cook) Conditions [2013F, Ch 18, Tbl 5B]


Appliance Broiler: underfired 3 ft Cheesemelter* Fryer: kettle Fryer: open deep-fat, 1-vat Fryer: pressure Griddle: double sided 3 ft (clamshell down)* Griddle: double sided 3 ft (clamshell up)* Griddle: flat 3 ft Griddle-small 3 ft* Induction cooktop* Induction wok* Oven: combi: combi-mode* Oven: combi: convection mode Oven: convection full-size Oven: convection half-size* Pasta cooker* Range top: top off/oven on* Range top: 3 elements on/ oven off Range top: 6 elements on/ oven off Range top: 6 elements on/ oven on Range: hot-top Rotisserie* Salamander* Steam kettle: large (60 gal) simmer lid down* Steam kettle: small (40 gal) simmer lid down* Steamer: compartment: atmospheric* Tilting skillet/braising pan

Energy Rate, Rate of Heat Gain, Btu/h Btu/h Rated Standby Sensible Radiant 36,900 30,900 10,800 12,300 11,900 4,600 99,000 1,800 500 47,800 2,800 1,000 46,100 2,700 500

Usage Radiation Factor Factor FR FU 0.84 0.97 0.02 0.06 0.06

0.35 0.39 0.28 0.36 0.19

72,400

6,900

1,400

0.10

0.20

72,400

11,500

3,600

0.16

0.31

58,400 30,700 71,700 11,900 56,000 56,000 41,300 18,800 75,100 16,600

11,500 6,100 0 0 5,500 5,500 6,700 3,700 8,500 4,000

4,500 2,700 0 0 800 1,400 1,500 500 0 1,000

0.20 0.20 0.00 0.00 0.10 0.10 0.16 0.20 0.11 0.24

0.39 0.44 0.00 0.00 0.15 0.25 0.22 0.14 0.00 0.25

51,200

15,400

6,300

0.30

0.41

51,200

33,200

13,900

0.65

0.42

67,800

36,400

14,500

0.54

0.40

54,000 37,900 23,900

51,300 13,800 23,300

11,800 4,500 7,000

0.95 0.36 0.97

0.23 0.33 0.30

110,600

2,600

100

0.02

0.04

73,700

1,800

300

0.02

0.17

33,400

15,300

200

0.46

0.01

32,900

5,300

0

0.16

0.00


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Rate of Heat Gain, Btu/h Standby Sensible 42,000 6200 49,600 7000

Dishwasher* (under-counter type, hot-water sanitizing) standby

Dishwasher* (under-counter type, chemical sanitizing) standby

Dishwasher (door-type, hot-water sanitizing) washing

Dishwasher (door-type, chemical sanitizing) washing

Dishwasher (conveyor type, hot-water sanitizing) standby

Standby/ Rated Washing 5700/ 46,800 43,600 5700/ 46,800 N/A 1200/ 18,400 13,300 1200/ 18,400 13,300 1200/ 26,600 18,700 1700/ 26,600 19,700 130,000 0

Energy Rate, Btu/h

500

800

0

0

0

0

0

0

1040

2280

1980

1980

4750

4450

0

3010

4170

2790

2790

16970

13490

0

4850

6450

4770

4770

21720

17940

Rate of Heat Gain, Btu/h Unhooded Sensible Sensible Latent Total Radiant Convective

*Items with an asterisk appear only in Swierczyna et al. (2009); all others appear in both Swierczyna et al. (2008) and (2009). Note: Heat load values are prorated for 30% washing and 70% standby.

Booster heater*

N/A N/A

Usage Factor FU 0.15 0.14

500

800

0

0

0

0

0

0

0.27

0.35

0.26

0.26

N/A

0.36

N/A

0.34

0.00

0

0

0

0

Radiation Factor FR

Radiation Factor FR

Usage Hooded Factor Sensible FU Radiant

Recommended Rates of Radiant and Convective Heat Gain from Warewashing Equipment during Idle (Standby) or Washing Conditions [2013F, Ch 18, Tbl 5E]

Dishwasher (conveyor type, chemical sanitizing)

Appliance

Table 12.25


Broiler: solid fuel: charcoal Broiler: solid fuel: wood (mesquite)*

Energy Rate, Btu/h Rated 40 lb 40 lb


Appliance

Table 12.24 Recommended Rates of Radiant Heat Gain from Hooded Solid Fuel Appliances during Idle (Ready-to-Cook) Conditions [2013F, Ch 18, Tbl 5D]



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Table 12.26

Recommended Rates of Radiant Heat Gain from Hooded Gas Appliances during Idle (Ready-to-Cook) Conditions [2013F, Ch 18, Tbl 5C]


Appliance Broiler: batch* Broiler: chain (conveyor) Broiler: overfired (upright)* Broiler: underfired 3 ft Fryer: doughnut Fryer: open deep-fat, 1 vat Fryer: pressure Griddle: double sided 3 ft (clamshell down)* Griddle: double sided 3 ft (clamshell up)* Griddle: flat 3 ft Oven: combi: combi-mode* Oven: combi: convection mode Oven: convection full-size Oven: conveyor (pizza) Oven: deck Oven: rack mini-rotating* Pasta cooker* Range top: top off/oven on* Range top: 3 burners on/oven off Range top: 6 burners on/oven off Range top: 6 burners on/oven on Range: wok* Rethermalizer* Rice cooker* Salamander* Steam kettle: large (60 gal) simmer lid down* Steam kettle: small (10 gal) simmer lid down* Steam kettle: small (40 gal) simmer lid down Steamer: compartment: atmospheric* Tilting skillet/braising pan

Rate of Heat Gain, Usage Radiation Btu/h Factor Factor FR FU Standby Sensible Radiant 69,200 8,100 0.73 0.12 96,700 13,200 0.73 0.14 87,900 2,500 0.88 0.03 73,900 9,000 0.77 0.12 12,400 2,900 0.28 0.23 4,700 1,100 0.06 0.23 9,000 800 0.11 0.09

Energy Rate, Btu/h Rated 95,000 132,000 100,000 96,000 44,000 80,000 80,000 108,200

8,000

1,800

0.07

0.23

108,200

14,700

4,900

0.14

0.33

90,000 75,700 75,700 44,000 170,000 105,000 56,300 80,000 25,000 120,000 120,000 145,000 99,000 90,000 35,000 35,000

20,400 6,000 5,800 11,900 68,300 20,500 4,500 23,700 7,400 60,100 120,800 122,900 87,400 23,300 500 33,300

3,700 400 1,000 1,000 7,800 3,500 1,100 0 2,000 7,100 11,500 13,600 5,200 11,500 300 5,300

0.23 0.08 0.08 0.27 0.40 0.20 0.08 0.30 0.30 0.50 1.01 0.85 0.88 0.26 0.01 0.95

0.18 0.07 0.17 0.08 0.11 0.17 0.24 0.00 0.27 0.12 0.10 0.11 0.06 0.49 0.60 0.16

145,000

5,400

0

0.04

0.00

52,000

3,300

300

0.06

0.09

100,000

4,300

0

0.04

0.00

26,000

8,300

0

0.32

0.00

104,000

10,400

400

0.10

0.04


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Hospital and Laboratory Equipment Heat gain varies significantly. In a laboratory, heat gain ranges from 15 to 70 Btuh/ft2. Medical equipment is highly varied in type and application. Table 12.21 is relevant for portable and bench-type equipment. For large equipment, such as MRI, obtain heat gain from the manufacturer. Table 12.27

Recommended Heat Gain from Typical Medical Equipment [2013F, Ch 18, Tbl 6]

Nameplate, W 250 500 180 360 1440 1000 1688 230 180 1200 330 72 N/A 1800 621 968 1725 2070

Peak, W 177 504 33 204 54 147 605 60 35 256 65 21 198 1063 337 534

Average, W 166 221 29 114 50 109 596 59 34 229 63 20 173 1050 302 82 480 18


Equipment Anesthesia system Blanket warmer Blood pressure meter Blood warmer ECG/RESP Electrosurgery Endoscope Harmonical scalpel Hysteroscopic pump Laser sonics Optical microscope Pulse oximeter Stress treadmill Ultrasound system Vacuum suction X-ray system

Source: Hosni et al. (1999)

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Table 12.28 Recommended Heat Gain from Typical Laboratory Equipment [2013F, Ch 18, Tbl 7]

Equipment Analytical balance Centrifuge

Electrochemical analyzer


Flame photometer Fluorescent microscope Function generator Incubator

Orbital shaker Oscilloscope Rotary evaporator Spectronics Spectrophotometer

Spectro fluorometer Thermocycler Tissue culture

Nameplate, W 7 138 288 5500 50 100 180 150 200 58 515 600 3125 100 72 345 75 94 36 575 200 N/A 340 1840 N/A 475 2346

Peak, W 7 89 136 1176 45 85 107 144 205 29 461 479 1335 16 38 99 74 29 31 106 122 127 405 965 233 132 1178

Average, W 7 87 132 730 44 84 105 143 178 29 451 264 1222 16 38 97 73 28 31 104 121 125 395 641 198 46 1146

Source: Hosni et al. (1999).

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Manufacturer A (model A); 2.8 GHz processor, 1 GB RAM Manufacturer A (model B); 2.6 GHz processor, 2 GB RAM Manufacturer B (model A); 3.0 GHz processor, 2 GB RAM Manufacturer B (model B); 3.0 GHz processor, 2 GB RAM Manufacturer A (model C); 2.3 GHz processor, 3 GB RAM Manufacturer 1; 2.0 GHz processor, 2 GB RAM, 17 in. screen Manufacturer 1; 1.8 GHz processor, 1 GB RAM, 17 in. screen Manufacturer 1; 2.0 GHz processor, 2 GB RAM, 14 in. screen Manufacturer 2; 2.13 GHz processor, 1 GB RAM, 14 in. screen, tablet PC Manufacturer 2; 366 MHz processor, 130 MB RAM (4 in. screen) Manufacturer 3; 900 MHz processor, 256 MB RAM (10.5 in. screen) Manufacturer X (model A); 30 in. screen Manufacturer X (model B); 22 in. screen Manufacturer Y (model A); 19 in. screen Manufacturer Y (model B); 17 in. screen Manufacturer Z (model A); 17 in. screen Manufacturer Z (model C); 15 in. screen

Description

Nameplate Power, W 480 480 690 690 1200 130 90 90 90 70 50 383 360 288 240 240 240

Recommended Heat Gain from Typical Computer Equipment [2013F, Ch 18, Tbl 8]


Average Power, W 73 49 77 48 97 36 23 31 29 22 12 90 36 28 27 29 19

Radiant Fraction 0.10a 0.10a 0.10a 0.10a 0.10a 0.25b 0.25b 0.25b 0.25b 0.25b 0.25b 0.40c 0.40c 0.40c 0.40c 0.40c 0.40c

Source: Hosni and Beck (2008). a Power consumption for newer desktop computers in operational mode varies from 50 to 100 W, but a conservative value of about 65 W may be used. Power consumption in sleep mode is negligible. Because of cooling fan, approximately 90% of load is by convection and 10% is by radiation. Actual power consumption is about 10 to 15% of nameplate value. b Power consumption of laptop computers is relatively small: depending on processor speed and screen size, it varies from about 15 to 40 W. Thus, differentiating between radiative and convective parts of the cooling load is unnecessary and the entire load may be classified as convective. Otherwise, a 75/25% split between convective and radiative components may be used. Actual power consumption for laptops is about 25% of nameplate values. c Flat-panel monitors have replaced cathode ray tube (CRT) monitors in many workplaces, providing better resolution and being much lighter. Power consumption depends on size and resolution, and ranges from about 20 W (for 15 in. size) to 90 W (for 30 in.). The most common sizes in workplaces are 19 and 22 in., for which an average 30 W power consumption value may be used. Use 60/40% split between convective and radiative components. In idle mode, monitors have negligible power consumption. Nameplate values should not be used.

Flat-panel monitorc

Laptop computerb

Desktop computera

Equipment

Table 12.29



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Table 12.30

Recommended Heat Gain from Typical Laser Printers and Copiers [2013F, Ch 18, Tbl 9]

Equipment

Description

Laser printer, typical desktop, small-office typea

Printing speed up to 10 pages per minute Printing speed up to 35 pages per minute Printing speed up to 19 pages per minute Printing speed up to 17 pages per minute Printing speed up to 19 pages per minute Printing speed up to 24 page per minute Small, desktop type

Multifunction (copy, print, scan)b Scannerb Copy machinec

Medium, desktop type Small, desktop type Large, multiuser, office type

Nameplate Power, W

Average Power, W

Radiant Fraction

430

137

0.30a

890

74

0.30a

508

88

0.30a

508

98

0.30a

635

110

0.30a

1344

130

0.30a

600 40 700 19

30 15 135 16 800 (idle 260 W) 550 (idle 135 W) 1060 (idle 305 W) 90 20 250 140

d d d d d (idle 0.00c) d (idle 0.00c) d (idle 0.00c) d d d d

1750 1440 1850

Fax machine Plotter

Medium Small Manufacturer A Manufacturer B

936 40 400 456

Source: Hosni and Beck (2008). Various laser printers commercially available and commonly used in personal offices were tested for power consumption in print mode, which varied from 75 to 140 W, depending on model, print capacity, and speed. Average power consumption of 110 W may be used. Split between convection and radiation is approximately 70/30%. b Small multifunction (copy, scan, print) systems use about 15 to 30 W; medium-sized ones use about 135 W. Power consumption in idle mode is negligible. Nameplate values do not represent actual power consumption and should not be used. Small, single-sheet scanners consume less than 20 W and do not contribute significantly to building cooling load. c Power consumption for large copy machines in large offices and copy centers ranges from about 550 to 1100 W in copy mode. Consumption in idle mode varies from about 130 to 300 W. Count idle-mode power consumption as mostly convective in cooling load calculations. d Split between convective and radiant heat gain was not determined for these types of equipment. a

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Table 12.31 Recommended Heat Gain from Miscellaneous Office Equipment [2013F, Ch 18, Tbl 10]

Equipment

Coffee maker, 10 cups Microfiche reader Microfilm reader Microfilm reader/printer Microwave oven, 1 ft3 Paper shredder Water cooler, 32 qt/h

Recommended Rate of Heat Gain, W

125 600 to 3300 600 to 6600 230

80 390 to 2150 390 to 4300 150

72 1150 to 1920 1725 240 to 275

72 575 to 960 862 240 to 275

440 60 4800

370 48 2470 1050 W sensible, 1540 Btu/h latent 85 520 1150 400 200 to 2420 350

1500 85 520 1150 600 250 to 3000 700


Mail-processing equipment Folding machine Inserting machine, 3600 to 6800 pieces/h Labeling machine, 1500 to 30,000 pieces/h Postage meter Vending machines Cigarette Cold food/beverage Hot beverage Snack Other Bar code printer Cash registers Check processing workstation,12 pockets

Maximum Input Rating, W

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Table 12.32

Recommended Load Factors for Various Types of Offices [2013F, Ch 18, Tbl 11]


Type of Use

Load Factor, W/ft2

Description

100% Laptop, light

0.25

167 ft2/workstation, all laptop use, 1 printer per 10, speakers, misc.

medium

0.33

125 ft2/workstation, all laptop use, 1 printer per 10, speakers, misc.

50% Laptop, light

0.40

167 ft2/workstation, 50% laptop / 50% desktop, 1 printer per 10, speakers, misc.

medium

0.50

125 ft2/workstation, 50% laptop / 50% desktop, 1 printer per 10, speakers, misc.

100% Desktop, light

0.60

167 ft2/workstation, all desktop use, 1 printer per 10, speakers, misc.

medium

0.80

125 ft2/workstation, all desktop use, 1 printer per 10, speakers, misc.

100% Desktop, two monitors

1.00

125 ft2/workstation, all desktop use, 2 monitors, 1 printer per 10, speakers, misc.

100% Desktop, heavy

1.50

85 ft2/workstation, all desktop use, 2 monitors, 1 printer per 8, speakers, misc.

100% Desktop, full on

2.00

85 ft2/workstation, all desktop use, 2 monitors, 1 printer per 8, speakers, misc., no diversity.

Source: Wilkins and Hosni (2011).

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Table 12.33

Recommended Diversity Factors for Office Equipment [2013F, Ch 18, Tbl 12]

Device Desktop computer LCD monitor Notebook computer

Recommended Diversity Factor 75% 60% 75%


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Table 12.34

Refrigerating Effect Produced by Open Refrigerated Display Fixtures

Btu/hft of Fixture*


Type of Display Fixture Low temperature Frozen Food Single Deck Single Deck, Double Island 2 Deck 3 Deck 4 or 5 Deck Ice Cream Single Deck Single Deck, Double Island Standard Temperature Meats Single Deck Multideck Dairy Multideck Produce Single Deck Multideck

Latent Heat

Sensible Heat

Total Refrigerating Effect

38 70 144 322 400

207 400 576 1288 1600

245 470 720 1610 2000

64 70

366 400

430 470

52 219

298 876

350 1095

196

784

980

36 192

204 768

240 960

* These figures are general magnitudes for fixtures adjusted for average desired product temperatures and apply to store ambients in front of the display cases of 72°F to 74°F with 50% to 55% rh. Raising the dry bulb only 3°F to 5°F and the humidity 5% to 10% can increase heat removal 25% or more. Equally lower temperatures and humidities as in winter, have an equally marked effect on lowering heat removal from the space.

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13_Ventilation.fm Page 211 Tuesday, October 7, 2014 2:34 PM © 2013 ASHRAE (www.ashrae.org). For personal use only. Additional reproduction, distribution, or transmission in either print or digital form is not permitted without ASHRAE's prior written permission.

13.

VENTILATION

ASHRAE Standard 62.2-2010, Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings (See complete standard for detailed guidance.) Low-rise residential ventilation for single and multiple family structures of three stories or fewer above grade, including manufactured and modular houses. Whole-house mechanical ventilation systems are required for each dwelling unit: cfm = 0.01 (ft2 floor area) + 7.5 (number of bedrooms + 1) Exceptions: (a) building has no mechanical cooling and is in zone 1 or 2 of the climate zone map (see Figure 14.1), or (b) building is thermally conditioned for human occupancy for less than 876 hours per year and if the authority having jurisdiction determines that window ventilation is sufficient. Alternate means may be used to provide the required ventilation rate when approved by a licensed design professional. In hot, humid climates, whole-house net mechanical exhaust shall not exceed 7.5 cfm per 100 ft2. In severe cold climates, net supply systems shall not exceed 7.5 cfm per 100 ft2. (Climates are defined in Figure 14.1.) Local mechanical exhaust rates are shown in Tables 13.1 and 13.2 Ventilation openings: not less than 4% of floor, nor less than 5 ft2 for habitable rooms; and not less than 4% of floor space, nor less than 1.5 ft2 for toilets and utility rooms. Supply ductwork for thermal conditioners except evaporative coolers, shall have a MERV 6 filter or better in accordance with ASHRAE Standard 52.2. Airflows all refer to delivered airflow as tested, or the fans’ rating at 0.25 in. w.g. with duct sizing meet the prescriptive sizing of Table 13.3.

Application Airflow Notes Vented range hood (including appliance-range hood combinations) Kitchen 100 cfm required if exhaust fan flow rate is less than 5 kitchen air changes per hour. Bathroom 50 cfm

Ventilation

Table 13.1 Intermittent Local Ventilation Exhaust Airflow Rates [Std 62.2-2010, Tbl 5.1]

Table 13.2 Continuous Local Ventilation Exhaust Airflow Rates [Std 62.2-2010, Tbl 5.2] Application Kitchen Bathroom

Airflow 5 ach 20 cfm

Notes Based on kitchen volume.

Table 13.3 Prescriptive Duct Sizing [Std 62.2-2010, Tbl 5.3] Duct Type Fan Rating cfm @ 0.25 in. w.g. Diameter, in. 3 4 5 6 7 and above

Flex Duct 50

80

100

X 70 NL NL NL

X 3 70 NL NL

X X 35 135 NL

Smooth Duct 125 50 Maximum Length, ft X 5 X 105 20 NL 95 NL NL NL

80

100

125

X 35 135 NL NL

X 5 85 NL NL

X X 55 145 NL

This table assumes no elbows. Deduct 15 ft of allowable duct length for each elbow. NL = no limit on duct length of this size X = not allowed, any length of duct of this size with assumed turns and fitting will exceed the rated pressure drop 211

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ASHRAE Standard 62.1-2010, Ventilation for Acceptable Indoor Air Quality (See complete standard for detailed guidance.)

Ventilation

General Use of natural ventilation systems is permitted in lieu of or in conjunction with mechanical ventilation. Naturally ventilated spaces shall be permanently open to operable wall or roof openings to the outdoors; free openable area at least 4% of net occupiable floor area. If interior spaces are ventilated through adjoining rooms, free area between rooms shall be permanently unobstructed and at least 8% of the area of the interior room, nor less than 25 ft2. Occupants must have ready access to the openings. All airstream surfaces shall be designed to resist mold growth and resist erosion. Ductwork construction shall meet SMACNA standards. Fuel-burning appliances shall have sufficient air for combustion and adequate removal of combustion products, which shall be vented directly outdoors. Filters or air cleaners with minimum MERV 6 by ASHRAE Standard 52.2 shall be provided upstream of all cooling coils or other devices with wetted surfaces through which air is supplied to occupiable space. Relative humidity should be below 65% when system performance is analyzed with outdoor at the design dew point and mean coincident dry bulb, sensible and latent space interior loads at cooling design values, and space solar loads at zero. Drain pans slope minimum 1/8 in. per ft to outlet at lowest point, and drain line shall have P-trap or other seal when drain pan is at negative static pressure relative to the outlet. Drain pan shall extend from leading edge of the coil to a distance of half the vertical dimension of the coil. Discharge from noncombustion equipment that captures contaminants generated by the equipment shall be discharged directly outdoors. Investigate outdoor air quality. Survey and document local outdoor air quality, with description of noticeable air problems and conditions regarding its acceptability. If unacceptable, treat it. Cleaning for ozone is required only if in a high-ozone area (see Appendix E of the standard) and if the minimum design outdoor airflow is 1.5 air changes or more. Outdoor air intakes shall be located so the shortest distance from intake to any specific contaminant source shall equal or exceed Table 5-1 of ASHRAE Standard 62.1. Design intakes to manage rain and snow entrainment and include bird screens.

Figure 13.1

Ventilation System [Std 62.1-2010, Fig 3.1]

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Table 13.4 Air Intake Minimum Separation Distance [Std 62.1-2010, Tbl 5-1] Object Class 2 air exhaust/relief outlet (Note 1) Class 3 air exhaust/relief outlet (Note 1) Class 4 air exhaust/relief outlet (Note 2) Plumbing vents terminating less than 3 ft above the level of the outdoor air intake Plumbing vents terminating at least 3 ft above the level of the outdoor air intake Vents, chimneys, and flues from combustion appliances and equipment (Note 3) Garage entry, automobile loading area, or drive-in queue (Note 4) Truck loading area or dock, bus parking/idling area (Note 4) Driveway, street, or parking place (Note 4) Thoroughfare with high traffic volume Roof, landscaped grade, or other surface directly below intake (Notes 5 and 6) Garbage storage/pick-up area, dumpsters Cooling tower intake or basin Cooling tower exhaust

Minimum Distance, ft 10 15 30 10 3 15 15 25 5 25 1 15 15 25

Ventilation

Note 1: This requirements applies to the distance from the outdoor air intakes for one ventilation system to the exhaust/relief outlets for any other ventilation system. Note 2: Minimum distance listed does not apply to laboratory fume hood exhaust air outlets. Separation criteria for fume hood exhaust shall be in compliance with NFPA 455 and ANSI/AIHA Z9.5.6 Information on separation criteria for industrial environments can be found in the ACGIH Industrial Ventilation Manual 7 and in the ASHRAE Handbook—HVAC Applications.8 Note 3: Shorter separation distances shall be permitted when determined in accordance with (a) ANSI Z223.1/NFPA 549 for fuel gas burning appliances and equipment, (b) NFPA 3110 for oil burning appliances and equipment, or (c) NFPA 21111 for other combustion appliances and equipment. Note 4: Distance measured to closest place that vehicle exhaust is likely to be located. Note 5: Shorter separation distance shall be permitted where outdoor surfaces are sloped more than 45 degrees from horizontal or that are less than 1 in. wide. Note 6: Where snow accumulation is expected, the surface of the snow at the expected average snow depth constitutes the “other surface directly below intake.”

Air classifications: • Class 1: Air with low contaminant concentration, low sensory-irritation intensity, and inoffensive odor. • Class 2: Air with moderate contaminant concentration, mild sensory-irritation intensity, or mildly offensive odors. Class 2 air also includes air that is not necessarily harmful or objectionable but that is inappropriate for transfer or recirculation to spaces used for different purposes. • Class 3: Air with significant contaminant concentration, significant sensory-irritation intensity, or offensive odor. • Class 4: Air with highly objectionable fumes or gases or with potentially dangerous particles, bioaerosols, or gases, at concentrations high enough to be considered harmful.

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Table 13.5 Airstreams [Std 62.1-2010, Tbl 5-2] Description Diazo printing equipment discharge Commercial kitchen grease hoods Commercial kitchen hoods other than grease Laboratory hoods Residential kitchen vented hoods Hydraulic elevator machine room

Air Class 4 4 3 4 3 2

The Ventilation Rate Procedure, the Natural Ventilation Procedure, or the Indoor Air Quality (IAQ) Procedure shall be used to design ventilation systems. The IAQ procedure is based on analysis of contaminant sources, concentrations, and targets, and perceived acceptability targets. Use design techniques that can be reliably demonstrated to result in indoor contaminant concentrations equal to or lower than achieved by the ventilation rate procedure.

Procedures from ASHRAE Standard 62.1-2010 6.2 Ventilation Rate Procedure. The outdoor air intake flow (Vot) for a ventilation system shall be determined in accordance with Sections 6.2.1 through 6.2.7. Note: Additional explanation of terms used below is contained in Appendix A, along with a ventilation system schematic (Figure A-1).

Ventilation

6.2.1 Outdoor Air Treatment. If outdoor air is judged to be unacceptable in accordance with Section 4.1, each ventilation system that provides outdoor air through a supply fan shall comply with the following sections. Exception: Systems supplying air for enclosed parking garages, warehouses, storage rooms, janitor’s closets, trash rooms, recycling areas, shipping/receiving/distribution areas. Note: Occupied spaces ventilated with outdoor air that is judged to be unacceptable are subject to reduced air quality when outdoor air is not cleaned prior to introduction to the occupied spaces. 6.2.1.1 Particulate Matter Smaller than 10 Micrometers (PM10). When the building is located in an area where the national standard or guideline for PM101 is exceeded, particle filters or air-cleaning devices shall be provided to clean the outdoor air at any location prior to its introduction to occupied spaces. Particulate matter filters or air cleaners shall have a Minimum Efficiency Reporting Value (MERV) of 6 or higher when rated in accordance with ANSI/ASHRAE Standard 52.2.15 Note: See Appendix E for resources regarding selected PM10 national standards and guidelines. 6.2.1.2 Particulate Matter Smaller than 2.5 Micrometers (PM2.5). When the building is located in an area where the national standard or guideline for PM2.51 is exceeded, particle filters or air cleaning devices shall be provided to clean the outdoor air at any location prior to its introduction to occupied spaces. Particulate matter filters or air cleaners shall have a Minimum Efficiency Reporting Value (MERV) of 11 or higher when rated in accordance with ASHRAE Standard 52.2.15 Note: See Appendix E for resources regarding selected PM2.5 national standards and guidelines. 6.2.1.3 Ozone. Air-cleaning devices for ozone shall be provided when the most recent threeyear average annual fourth-highest daily maximum eight-hour average ozone concentration exceeds 0.107 ppm (209 g/m3). Note: See Appendix E for a list of United States locations exceeding the most recent 3-year average annual fourth-highest daily maximum 8-hour average ozone concentration of 0.107 ppm. Such air-cleaning devices shall have a minimum volumetric ozone removal efficiency of 40% when installed, operated, and maintained in accordance with manufacturer recommendations and shall be approved by the authority having jurisdiction. Such devices shall be operated whenever outdoor ozone levels are expected to exceed 0.107 ppm. 214

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Exceptions: Air cleaning for ozone is not required when: a. The minimum system design outdoor air intake flow results in 1.5 ach or less. b. Controls are provided that sense outdoor ozone level and reduce intake airflow to result in 1.5 ach or less while complying with the outdoor airflow requirements of Section 6. c. Outdoor air is brought into the building and heated by direct-fired, makeup air units. 6.2.1.4 Other Outdoor Contaminants. When the building is located in an area where the national standard for one or more contaminants not specifically addressed in Section 6.2.1 is exceeded, any design assumptions and/or calculations related to the impact on indoor air quality shall be included in the design documents. 6.2.2 Zone Calculations. Ventilation zone parameters shall be determined in accordance with Sections 6.2.2.1 through 6.2.2.3 for each ventilation zone served by the ventilation system. 6.2.2.1 Breathing Zone Outdoor Airflow. The outdoor airflow required in the breathing zone of the occupiable space or spaces in a ventilation zone, i.e., the breathing zone outdoor airflow (Vbz), shall be no less than the value determined in accordance with Equation 6-1. Vbz = Rp · Pz + Ra · Az where Az = Pz = Rp = Ra

=

(6-1)

zone floor area: the net occupiable floor area of the ventilation zone ft2 zone population: the number of people in the ventilation zone during typical usage. outdoor airflow rate required per person as determined from Table 6-1 Note: These values are based on adapted occupants. outdoor airflow rate required per unit area as determined from Table 6-1

Ventilation

Note: Equation 6-1 accounts for people-related sources and area-related sources independently in the determination of the outdoor air rate required at the breathing zone. The use of Equation 6-1 in the context of this standard does not necessarily imply that simple addition of outdoor airflow rates for different sources can be applied to any other aspect of indoor air quality. 6.2.2.1.1 Design Zone Population. Design zone population (Pz ) shall equal the largest (peak) number of people expected to occupy the ventilation zone during typical usage. Exceptions: a. If the number of people expected to occupy the ventilation zone fluctuates, zone population equal to the average number of people shall be permitted, provided such average is determined in accordance with Section 6.2.6.2. b. If the largest or average number of people expected to occupy the ventilation zone cannot be established for a specific design, an estimated value for zone population shall be permitted, provided such value is the product of the net occupiable area of the ventilation zone and the default occupant density listed in Table 6-1. 6.2.2.2 Zone Air Distribution Effectiveness. The zone air distribution effectiveness (Ez) shall be no greater than the default value determined using Table 6-2. Note: For some configurations, the default value depends upon space and supply air temperature. 6.2.2.3 Zone Outdoor Airflow. The zone outdoor airflow (Voz), i.e., the outdoor airflow rate that must be provided to the ventilation zone by the supply air distribution system, shall be determined in accordance with Equation 6-2. Voz = Vbz/Ez

(6-2)

6.2.3 Single-Zone Systems. For ventilation systems wherein one or more air handlers supply a mixture of outdoor air and recirculated air to only one ventilation zone, the outdoor air intake flow (Vot) shall be determined in accordance with Equation 6-3. Vot = Voz

(6-3)

6.2.4 100% Outdoor Air Systems. For ventilation systems wherein one or more air handlers supply only outdoor air to one or more ventilation zones, the outdoor air intake flow (Vot) shall be determined in accordance with Equation 6-4. Vot = all zonesVoz

(6-4) 215

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Table 6-1 Minimum Ventilation Rates In Breathing Zone (This table is not valid in isolation; it must be used in conjunction with the accompanying notes.)

Occupancy Category

People Outdoor Air Rate Rp

Area Outdoor Air Rate Ra

Default Values

Notes

Occupant Density (see Note 4)

Combined Outdoor Air Rate (see Note 5)

Air Class

cfm/ person

L/s· person

cfm/ft2

L/s·m2

#/1000 ft2 or #/100 m2

cfm/ person

L/s· person

Cell

5

2.5

0.12

0.6

25

10

4.9

2

Dayroom

5

2.5

0.06

0.3

30

7

3.5

1

Guard stations

5

2.5

0.06

0.3

15

9

4.5

1

7.5

3.8

0.06

0.3

50

9

4.4

2

Correctional Facilities

Booking/waiting

Ventilation

Educational Facilities Daycare (through age 4)

10

5

0.18

0.9

25

17

8.6

2

Daycare sickroom

10

5

0.18

0.9

25

17

8.6

3

Classrooms (ages 5–8)

10

5

0.12

0.6

25

15

7.4

1

Classrooms (age 9 plus)

10

5

0.12

0.6

35

13

6.7

1

Lecture classroom

7.5

3.8

0.06

0.3

65

8

4.3

1

Lecture hall (fixed seats)

7.5

3.8

0.06

0.3

150

8

4.0

1

Art classroom

10

5

0.18

0.9

20

19

9.5

2

Science laboratories

10

5

0.18

0.9

25

17

8.6

2

University/college laboratories

10

5

0.18

0.9

25

17

8.6

2

Wood/metal shop

10

5

0.18

0.9

20

19

9.5

2

Computer lab

10

5

0.12

0.6

25

15

7.4

1

Media center

10

5

0.12

0.6

25

15

7.4

1

Music/theater/dance

10

5

0.06

0.3

35

12

5.9

1

Multi-use assembly

7.5

3.8

0.06

0.3

100

8

4.1

1

Restaurant dining rooms

7.5

3.8

0.18

0.9

70

10

5.1

2

Cafeteria/fast-food dining

7.5

3.8

0.18

0.9

100

9

4.7

2

Bars, cocktail lounges

7.5

3.8

0.18

0.9

100

9

4.7

2

Kitchen (cooking)

7.5

3.8

0.12

0.6

20

14

7.0

2

Break rooms

5

2.5

0.06

0.3

25

7

3.5

1

Coffee stations

5

2.5

0.06

0.3

20

8

4

1

Conference/meeting

5

2.5

0.06

0.3

50

6

3.1

1

Corridors

–

–

0.06

0.3

–

Occupiable storage rooms for liquids or gels

5

2.5

0.12

0.6

2

65

32.5

2

A

Food and Beverage Service

General

B

1

Hotels, Motels, Resorts, Dormitories Bedroom/living room

5

2.5

0.06

0.3

10

11

5.5

1

Barracks sleeping areas

5

2.5

0.06

0.3

20

8

4.0

1

Laundry rooms, central

5

2.5

0.12

0.6

10

17

8.5

2

Laundry rooms within dwelling units

5

2.5

0.12

0.6

10

17

8.5

1

7.5

3.8

0.06

0.3

30

10

4.8

1

5

2.5

0.06

0.3

120

6

2.8

1

Lobbies/prefunction Multipurpose assembly

216

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Table 6-1 Minimum Ventilation Rates In Breathing Zone (Continued) (This table is not valid in isolation; it must be used in conjunction with the accompanying notes.)

Occupancy Category



Default Values

Notes


Combined Outdoor Air Rate (see Note 5) cfm/ person

L/s· person

Air Class

cfm/ person

L/s· person

cfm/ft2

L/s·m2

#/1000 ft2 or #/100 m2

Breakrooms

5

2.5

0.12

0.6

50

7

3.5

1

Main entry lobbies

5

2.5

0.06

0.3

10

11

5.5

1

Occupiable storage rooms for dry materials

5

2.5

0.06

0.3

2

35

17.5

1

Office space

5

2.5

0.06

0.3

5

17

8.5

1

Reception areas

5

2.5

0.06

0.3

30

7

3.5

1

Telephone/data entry

5

2.5

0.06

0.3

60

6

3.0

1

Office Buildings

Miscellaneous Spaces Bank vaults/safe deposit

2.5

0.06

0.3

5

17

8.5

2

3.8

0.06

0.3

15

12

6.0

1

Computer (not printing)

5

2.5

0.06

0.3

4

20

10.0

1

General manufacturing (excludes heavy industrial and processes using chemicals)

10

5.0

0.18

0.9

7

36

18

3

Pharmacy (prep. area)

5

2.5

0.18

0.9

10

23

11.5

2

Photo studios

5

2.5

0.12

0.6

10

17

8.5

1

Shipping/receiving

10

5

0.12

0.6

2

70

35

2

Sorting, packing, light assembly

7.5

3.8

0.12

0.6

7

25

12.5

–

–

0.00

0.0

–

Transportation waiting

7.5

3.8

0.06

0.3

Warehouses

10

5

0.06

0.3

Auditorium seating area

5

2.5

0.06

0.3

150

5

2.7

1

Places of religious worship

5

2.5

0.06

0.3

120

6

2.8

1

Courtrooms

5

2.5

0.06

0.3

70

6

2.9

1

Legislative chambers

5

2.5

0.06

0.3

50

6

3.1

1

Libraries

5

2.5

0.12

0.6

10

17

8.5

1

Lobbies

5

2.5

0.06

0.3

150

5

2.7

1

Museums (children’s)

7.5

3.8

0.12

0.6

40

11

5.3

1

Museums/galleries

7.5

3.8

0.06

0.3

40

9

4.6

1

Dwelling unit

5

2.5

0.06

0.3

Common corridors

–

–

0.06

0.3

Sales (except as below)

7.5

3.8

0.12

0.6

15

16

7.8

2

Mall common areas

7.5

3.8

0.06

0.3

40

9

4.6

1

Barbershop

7.5

3.8

0.06

0.3

25

10

5.0

2

Beauty and nail salons

20

10

0.12

0.6

25

25

12.4

2

Telephone closets

B

100 B

Ventilation

5 7.5

Banks or bank lobbies

2 1

8

4.1

–

1 2

Public Assembly Spaces

Residential F,G

F

1 1

Retail

217

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Table 6-1 Minimum Ventilation Rates In Breathing Zone (Continued) (This table is not valid in isolation; it must be used in conjunction with the accompanying notes.)

Occupancy Category



Default Values

Notes


Combined Outdoor Air Rate (see Note 5)

Air Class

cfm/ person

L/s· person

cfm/ft2

L/s·m2

#/1000 ft2 or #/100 m2

cfm/ person

L/s· person

Pet shops (animal areas)

7.5

3.8

0.18

0.9

10

26

12.8

Supermarket

7.5

3.8

0.06

0.3

8

15

7.6

1

Coin-operated laundries

7.5

3.8

0.12

0.6

20

14

7.0

2

2

Sports and Entertainment Sports arena (play area)

–

–

0.30

1.5

Gym, stadium (play area)

–

–

0.30

1.5

30

7.5

3.8

0.06

0.3

150

Swimming (pool & deck)

–

–

0.48

2.4

Disco/dance floors

20

10

0.06

0.3

Health club/aerobics room

20

10

0.06

Health club/weight rooms

20

10

Bowling alley (seating)

10

Gambling casinos Ventilation

Spectator areas

E

–

1 2 8

4.0

100

21

10.3

2

0.3

40

22

10.8

2

0.06

0.3

10

26

13.0

2

5

0.12

0.6

40

13

6.5

1

7.5

3.8

0.18

0.9

120

9

4.6

1

Game arcades

7.5

3.8

0.18

0.9

20

17

8.3

1

Stages, studios

10

5

0.06

0.3

70

11

5.4

1

C

D

–

1 2

GENERAL NOTES FOR TABLE 6-1 1 Related requirements: The rates in this table are based on all other applicable requirements of this standard being met. 2 Environmental Tobacco Smoke: This table applies to ETS-free areas. Refer to Section 5.17 for requirements for buildings containing ETS areas and ETS-free areas. 3 Air density: Volumetric airflow rates are based on an air density of 0.075 lbda/ft3 (1.2 kgda/m3), which corresponds to dry air at a barometric pressure of 1 atm (101.3 kPa) and an air temperature of 70°F (21°C). Rates may be adjusted for actual density but such adjustment is not required for compliance with this standard. 4 Default occupant density: The default occupant density shall be used when actual occupant density is not known. 5 Default combined outdoor air rate (per person): This rate is based on the default occupant density. 6 Unlisted occupancies: If the occupancy category for a proposed space or zone is not listed, the requirements for the listed occupancy category that is most similar in terms of occupant density, activities and building construction shall be used. ITEM-SPECIFIC NOTES FOR TABLE 6-1 A For high school and college libraries, use values shown for Public Assembly Spaces—Libraries. B Rate may not be sufficient when stored materials include those having potentially harmful emissions. C Rate does not allow for humidity control. Additional ventilation or dehumidification may be required to remove moisture. “Deck area” refers to the area surrounding the pool that would be expected to be wetted during normal pool use, i.e., when the pool is occupied. Deck area that is not expected to be wetted shall be designated as a space type (for example, “spectator area”). D Rate does not include special exhaust for stage effects, e.g., dry ice vapors, smoke. E When combustion equipment is intended to be used on the playing surface, additional dilution ventilation and/or source control shall be provided. F Default occupancy for dwelling units shall be two persons for studio and one-bedroom units, with one additional person for each additional bedroom. GAir from one residential dwelling shall not be recirculated or transferred to any other space outside of that dwelling.

218

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Table 6-2 Zone Air Distribution Effectiveness Air Distribution Configuration

Ez

Ceiling supply of cool air. Ceiling supply of warm air and floor return. Ceiling supply of warm air 15°F or more above space temperature and ceiling return. Ceiling supply of warm air less than 15°F above space temperature and ceiling return provided that the 150 fpm supply air jet reaches to within 4.5 ft of floor level. Note: For lower velocity supply air, Ez = 0.8. Floor supply of cool air and ceiling return provided that the 150 fpm supply jet reaches 4.5 ft or more above the floor. Note: Most underfloor air distribution systems comply with this proviso. Floor supply of cool air and ceiling return, provided low-velocity displacement ventilation achieves unidirectional flow and thermal stratification. Floor supply of warm air and floor return. Floor supply of warm air and ceiling return. Makeup supply drawn in on the opposite side of the room from the exhaust and/or return. Makeup supply drawn in near to the exhaust and/or return location.

1.0 1.0 0.8 1.0

1.0 1.2 1.0 0.7 0.8 0.5

6.2.5 Multiple-Zone Recirculating Systems. For ventilation systems wherein one or more air handlers supply a mixture of outdoor air and recirculated air to more than one ventilation zone, the outdoor air intake flow (Vot) shall be determined in accordance with Sections 6.2.5.1 through 6.2.5.4. 6.2.5.1 Primary Outdoor Air Fraction. Primary outdoor air fraction (Zpz) shall be determined for ventilation zones in accordance with Equation 6-5. Zpz = Voz/Vpz

Ventilation

1. “Cool air” is air cooler than space temperature. 2. “Warm air” is air warmer than space temperature. 3. “Ceiling” includes any point above the breathing zone. 4. “Floor” includes any point below the breathing zone. 5. As an alternative to using the above values, Ez may be regarded as equal to air change effectiveness determined in accordance with ANSI/ASHRAE Standard 12917 for all air distribution configurations except unidirectional flow.

(6-5)

where Vpz is the zone primary airflow, i.e., the primary airflow rate to the ventilation zone from the air handler, including outdoor air and recirculated air. Note: For VAV-system design purposes, Vpz is the lowest zone primary airflow value expected at the design condition analyzed. Note: In some cases it is acceptable to determine these parameters for only selected zones as outlined in Normative Appendix A. 6.2.5.2 System Ventilation Efficiency. The system ventilation efficiency (Ev) shall be determined in accordance with Table 6-3 or Normative Appendix A. 6.2.5.3 Uncorrected Outdoor Air Intake. The uncorrected outdoor air intake (Vou) flow shall be determined in accordance with Equation 6-6. Vou = Dall zones(Rp · Pz) + all zones(Ra · Az)

(6-6)

6.2.5.3.1 Occupant Diversity. The occupant diversity ratio (D) shall be determined in accordance with Equation 6-7 to account for variations in population within the ventilation zones served by the system. D = Ps / all zones Pz ,

(6-7)

where the system population (Ps) is the total population in the area served by the system. Exception: Alternative methods to account for occupant diversity shall be permitted, provided that the resulting Vou value is no less than that determined using Equation 6-6. 219

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Table 6-3 System Ventilation Efficiency Ev 1.0 0.9 0.8 0.7 0.6 Use Appendix A

Max (ZP) 0.15 0.25 0.35 0.45 0.55 >0.55

Ventilation

1. “Max (Zpz)” refers to the largest value of Zpz, calculated using Equation 6-5, among all the ventilation zones served by the system. 2. For values of Max (Zpz) between 0.15 and 0.55, the corresponding value of Ev may be determined by interpolating the values in the table. 3. The values of Ev in this table are based on a 0.15 average outdoor air fraction for the system (i.e., the ratio of the uncorrected outdoor air intake (Vou) to the total zone primary airflow for all the zones served by the air handler). For systems with higher values of the average outdoor air fraction, this table may result in unrealistically low values of Ev and the use of Appendix A may yield more practical results.

Note: The uncorrected outdoor air intake (Vou) is adjusted for occupant diversity, but it is not corrected for system ventilation efficiency. 6.2.5.3.2 Design System Population. Design system population (Ps) shall equal the largest (peak) number of people expected to occupy all ventilation zones served by the ventilation system during typical usage. Note: Design system population is always equal to or less than the sum of design zone population for all zones in the area served by the system, since all zones may or may not be simultaneously occupied at design population. 6.2.5.4 Outdoor Air Intake. The design outdoor air intake flow (Vot) shall be determined in accordance with Equation 6-8. Vot = Vou/Ev

(6-8)

6.2.6 Design for Varying Operating Conditions 6.2.6.1 Variable Load Conditions. Ventilation systems shall be designed to be capable of providing no less than the minimum ventilation rates required in the breathing zone whenever the zones served by the system are occupied, including all full- and part-load conditions. Note: The minimum outdoor air intake flow may be less than the design value at part-load conditions. 6.2.6.2 Short-Term Conditions. If it is known that peak occupancy will be of short duration and/or ventilation will be varied or interrupted for a short period of time, the design may be based on the average conditions over a time period (T) determined by Equation 6-9a using I-P units (Equation 6-9b using SI units). T = 3v/Vbz where T = v = Vbz =

(6-9)

averaging time period, min the volume of the ventilation zone for which averaging is being applied, ft3 the breathing zone outdoor airflow calculated using Equation 6-1 and the design value of the zone population (Pz), cfm

Acceptable design adjustments based on this optional provision include the following: a. Zones with fluctuating occupancy: the zone population (Pz) may be averaged over time (T ). b. Zones with intermittent interruption of supply air: the average outdoor airflow supplied to the breathing zone over time (T) shall be no less than the breathing zone outdoor airflow (Vbz) calculated using Equation 6-1. c. Systems with intermittent closure of the outdoor air intake: the average outdoor air intake over time (T ) shall be no less than the minimum outdoor air intake (Vot) calculated using Equation 6-3, 6-4, or 6-8 as appropriate. 220

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6.2.7 Dynamic Reset. The system may be designed to reset the outdoor air intake flow (Vot) and/or space or ventilation zone airflow (Voz) as operating conditions change. 6.2.7.1 Demand Control Ventilation (DCV) 6.2.7.1.1 DCV shall be permitted as an optional means of dynamic reset. Exception: CO2-based DCV shall not be applied in zones with indoor sources of CO2 other than occupants or with CO2 removal mechanisms, such as gaseous air cleaners. 6.2.7.1.2 The breathing zone outdoor airflow (Vbz) shall be reset in response to current occupancy and shall be no less than the building component (Ra·Az) of the DCV zone. Note: Examples of reset methods or devices include population counters, carbon dioxide (CO2) sensors, timers, occupancy schedules or occupancy sensors. 6.2.7.1.3 The ventilation system shall be controlled such that at steady-state it provides each zone with no less than the breathing zone outdoor airflow (Vbz) for the current zone population. 6.2.7.1.4 When the mechanical air-conditioning system is dehumidifying, the current total outdoor air intake flow for the building shall be no less than the coincident total exhaust airflow. 6.2.7.1.5 Documentation. A written description of the equipment, methods, control sequences, set points, and the intended operational functions shall be provided. A table shall be provided that shows the minimum and maximum outdoor intake airflow for each system. 6.2.7.2 Ventilation Efficiency. Variations in the efficiency with which outdoor air is distributed to the occupants under different ventilation system airflows and temperatures shall be permitted as an optional basis of dynamic reset. 6.2.7.3 Outdoor Air Fraction. A higher fraction of outdoor air in the air supply due to intake of additional outdoor air for free cooling or exhaust air makeup shall be permitted as an optional basis of dynamic reset.

Ventilation

6.3 Indoor Air Quality (IAQ) Procedure. Breathing zone outdoor airflow (Vbz) and/or system outdoor air intake flow (Vot) shall be determined in accordance with Sections 6.3.1 through 6.3.5. 6.3.1 Contaminant Sources. Contaminants or mixtures of concern for purposes of the design shall be identified. For each contaminant or mixture of concern, indoor sources (occupants and materials) and outdoor sources shall be identified, and the emission rate for each contaminant of concern from each source shall be determined. Note: Appendix B lists information for some potential contaminants of concern. 6.3.2 Contaminant Concentration. For each contaminant of concern, a concentration limit and its corresponding exposure period and an appropriate reference to a cognizant authority shall be specified. Note: Appendix B includes concentration guidelines for some potential contaminants of concern. 6.3.3 Perceived Indoor Air Quality. The design level of indoor air acceptability shall be specified in terms of the percentage of building occupants and/or visitors expressing satisfaction with perceived IAQ. 6.3.4 Design Approach. Zone and system outdoor airflow rates shall be the larger of those determined in accordance with Section 6.3.4.1 and either 6.3.4.2 or 6.3.4.3, based on emission rates, concentration limits, and other relevant design parameters (e.g., air cleaning efficiencies and supply airflow rates). 6.3.4.1 Mass Balance Analysis. Using a steady-state or dynamic mass-balance analysis, determine the minimum outdoor airflow rates required to achieve the concentration limits specified in Section 6.3.2 for each contaminant or mixture of concern within each zone served by the system. Notes: a. Appendix D includes steady-state mass-balance equations that describe the impact of air cleaning on outdoor air and recirculation rates for ventilation systems serving a single zone. b. In the completed building, measurement of the concentration of contaminants or mixtures of concern may be useful as a means of checking the accuracy of the design mass-balance analysis, but such measurement is not required for compliance. 6.3.4.2 Subjective Evaluation. Using a subjective occupant evaluation conducted in the completed building, determine the minimum outdoor airflow rates required to achieve the level of acceptability specified in Section 6.3.3 within each zone served by the system. 221

further reproduc


Notes: a. Appendix B presents one approach to subjective occupant evaluation. b. Level of acceptability often increases in response to increased outdoor airflow rates, increased level of indoor and/or outdoor air cleaning, or decreased indoor and/or outdoor contaminant emission rate.

Ventilation

6.3.4.3 Similar Zone. The minimum outdoor airflow rates shall be no less than those found in accordance with Section 6.3.4.2 for a substantially similar zone (i.e., in a zone with identical contaminants of concern, concentration limits, air cleaning efficiency, and specified level of acceptability; and with similar contaminant sources and emission rates). 6.3.5 Combined IAQ Procedure and Ventilation Rate Procedure. The IAQ procedure in conjunction with the Ventilation Rate Procedure may be applied to a zone or system. In this case, the Ventilation Rate Procedure shall be used to determine the required zone minimum outdoor airflow, and the IAQ Procedure shall be used to determine the additional outdoor air or air cleaning necessary to achieve the concentration limits of the contaminants of concern. Note: The improvement of indoor air quality through the use of air cleaning or provision of additional outdoor air in conjunction with minimum ventilation rates may be quantified using the IAQ procedure. 6.3.6 Documentation. When the IAQ Procedure is used, the following information shall be included in the design documentation: the contaminants of concern considered in the design process, the sources and emission rates of the contaminants of concern, the concentration limits and exposure periods and the references for these limits, and the analytical approach used to determine ventilation rates and air cleaning requirements. The contaminant monitoring and occupant and/or visitor evaluation plans shall also be included in the documentation. 6.4 Natural Ventilation Procedure. Natural ventilation systems shall be designed in accordance with this section and shall include mechanical ventilation systems designed in accordance with Section 6.2 and/or Section 6.3. Exceptions: a. An engineered natural ventilation system, when approved by the authority having jurisdiction, need not meet the requirements of Section 6.4. b. The mechanical ventilation systems are not required when: 1.Natural ventilation openings that comply with the requirements of Section 6.4 are permanently open or have controls that prevent the openings from being closed during periods of expected occupancy, or 2.The zone is not served by heating or cooling equipment. 6.4.1 Floor Area to Be Ventilated. Spaces, or portions of spaces, to be naturally ventilated must be located within a distance based on the ceiling height, as determined by Sections 6.4.1.1, 6.4.1.2, or 6.4.1.3, from operable wall openings that meet the requirements of Section 6.4.2. For spaces with ceilings which are not parallel to the floor, the ceiling height shall be determined in accordance with Section 6.4.1.4. 6.4.1.1 Single Side Opening. For spaces with operable openings on one side of the space, the maximum distance from the operable openings is 2H, where H is the ceiling height. 6.4.1.2 Double Side Opening. For spaces with operable openings on two opposite sides of the space, the maximum distance from the operable openings is 5H, where H is the ceiling height. 6.4.1.3 Corner Openings. For spaces with operable openings on two adjacent sides of a space (i.e. two sides of a corner), the maximum distance from the operable openings is 5H along a line drawn between the two openings which are farthest apart. Floor area outside that line must comply with Section 6.4.1.1. 6.4.1.4 Ceiling Height. The ceiling height, H, to be used in Sections 6.4.1.1 through 6.4.1.3 shall be the minimum ceiling height in the space. Exception: For ceilings that are increasing in height as distance from the openings is increased, the ceiling height shall be determined as the average height of the ceiling within 20 ft from the operable openings. 6.4.2 Location and Size of Openings. Spaces, or portions of spaces, to be naturally ventilated shall be permanently open to operable wall openings directly to the outdoors, the openable area of which is a minimum of 4% of the net occupiable floor area. Where openings are covered with louvers or otherwise obstructed, openable area shall be based on the net free unobstructed area 222

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through the opening. Where interior rooms, or portions of rooms, without direct openings to the outdoors are ventilated through adjoining rooms, the opening between rooms shall be permanently unobstructed and have a free area of not less than 8% of the area of the interior room nor less than 25 ft2. 6.4.3 Control and Accessibility. The means to open required operable openings shall be readily accessible to building occupants whenever the space is occupied. Controls shall be designed to properly coordinate operation of the natural and mechanical ventilation systems. 6.5 Exhaust Ventilation. The design exhaust airflow shall be determined in accordance with the requirements in Table 6-4. Exhaust makeup air may be any combination of outdoor air, recirculated air, and transfer air. 6.6 Design Documentation Procedures. Design criteria and assumptions shall be documented and should be made available for operation of the system within a reasonable time after installation. See Sections 4.3, 5.1.3, 5.16.4, 6.2.7.1.5, and 6.3.6 regarding assumptions that should be detailed in the documentation. Table 6-4 Minimum Exhaust Rates Occupancy Category

Exhaust Rate, cfm/unit — — — — — — — — — — — — — — — — — — 50/100 — — 25/50 50/70 —

Exhaust Rate, cfm/ft2 0.50 0.70 1.50 0.50 0.60 1.00 0.50 1.00 1.00 1.00 0.30 0.70 0.25 0.50 — 0.75 0.90 — — 1.00 1.50 — — 0.50

Notes B A

F C F G F F E D

Air Class 1 2 2 2 2 2 2 2 2 3 2 2 2 2 4 2 2 3 2 3 4 2 2 2

Ventilation

Arenas Art classrooms Auto repair rooms Barber shops Beauty and nail salons Cells with toilet Copy, printing rooms Darkrooms Educational science laboratories Janitor closets, trash rooms, recycling Kitchenettes Kitchens—commercial Locker/dressing rooms Locker rooms Paint spray booths Parking garages Pet shops (animal areas) Refrigerating machinery rooms Residential kitchens Soiled laundry storage rooms Storage rooms, chemical Toilets—private Toilets—public Woodwork shop/classrooms

A Stands where engines are run shall have exhaust systems that directly connect to the engine exhaust and prevent escape of fumes. B When combustion equipment is intended to be used on the playing surface additional dilution ventilation and/or source control shall be provided. C Exhaust not required if two or more sides comprise walls that are at least 50% open to the outside. D Rate is per water closet and/or urinal. Provide the higher rate where periods of heavy use are expected to occur, e.g., toilets in theatres, schools, and sports facilities. The lower rate may be used otherwise. E Rate is for a toilet room intended to be occupied by one person at a time. For continuous system operation during normal hours of use, the lower rate may be used. Otherwise use the higher rate. F See other applicable standards for exhaust rate. G For continuous system operation, the lower rate may be used. Otherwise use the higher rate. 223

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NORMATIVE APPENDIX A—MULTIPLE-ZONE SYSTEMS This appendix presents an alternative procedure for calculating the system ventilation efficiency (Ev) that must be used when Table 6-3 values are not used. In this alternative procedure, Ev is equal to the lowest calculated value of the zone ventilation efficiency (Evz) (see Equation A-8). Figure A-1 contains a ventilation system schematic depicting most of the quantities used in this appendix. A1. SYSTEM VENTILATION EFFICIENCY For any multiple-zone recirculating system, the system ventilation efficiency (Ev) shall be calculated in accordance with Sections A1.1 through A1.3. A1.1 Average Outdoor Air Fraction. The average outdoor air fraction (Xs) for the ventilation system shall be determined in accordance with Equation A-1.

Ventilation

Xs = Vou/Vps

(A-1)

where the uncorrected outdoor air intake (Vou) is found in accordance with Section 6.2.5.3, and the system primary airflow (Vps) is found at the condition analyzed. Note: For VAV system design purposes, Vps is the highest expected system primary airflow at the design condition analyzed. System primary airflow at design is usually less than the sum of design zone primary airflow values, since primary airflow seldom peaks simultaneously in all VAV zones. A1.2 Zone Ventilation Efficiency. The zone ventilation efficiency (Evz), i.e., the efficiency with which a system distributes outdoor air from the intake to an individual breathing zone, shall be determined in accordance with Section A1.2.1 or A1.2.2. A1.2.1 Single-Supply Systems. For “single supply” systems, wherein all of the air supplied to each ventilation zone is a mixture of outdoor air and system-level recirculated air, zone ventilation efficiency (Evz) shall be determined in accordance with Equation A-2. Examples of single-supply systems include constant volume reheat, single-duct VAV, single-fan dual-duct, and multizone systems.

Figure A-1

Ventilation System Schematic

224

further reproduc


Evz = 1 + Xs – Zpz

(A-2)

where the average outdoor air fraction (Xs) for the system is determined in accordance with Equation A-1 and the primary outdoor air fraction (Zpz) for the zone is determined in accordance with Section 6.2.5.1. A1.2.2 Secondary Recirculation Systems. For “secondary-recirculation” systems wherein all or part of the supply air to each ventilation zone is recirculated air (which has not been directly mixed with outdoor air) from other zones, zone ventilation efficiency (Evz) shall be determined in accordance with Equation A-3. Examples of secondary-recirculation systems include dual-fan dual-duct and fan-powered mixing-box systems, and systems that include transfer fans for conference rooms. (A-3) Evz = (Fa + Xs · Fb – Zpz · Ep · Fc )/Fa where system air fractions Fa, Fb, and Fc are determined in accordance with Equation A-4, A-5, and A-6, respectively. (A-4) Fa = Ep + (1 – Ep) · Er Fb = Ep

(A-5)

Fc = 1 – (1 – Ez) · (1 – Er) · (1 – Ep)

(A-6)

Ep = Vpz /Vdz

Ventilation

where the zone primary air fraction (Ep) is determined in accordance with Equation A-7; zone secondary recirculation fraction (Er) is determined by the designer based on system configuration; and zone air distribution effectiveness (Ez) is determined in accordance with Section 6.2.2.2. Note: For plenum return systems with secondary recirculation (e.g., fan-powered AV with plenum return) Er is usually less than 1.0, although values may range from 0.1 to 1.2 depending upon the location of the ventilation zone relative to other zones and the air handler. For ducted return systems with secondary recirculation (e.g., fan-powered VAV with ducted return), Er is typically 0.0, while for those with system-level recirculation (e.g, dual-fan dual-duct systems with ducted return) Er is typically 1.0. For other system types, Er is typically 0.75. (A-7)

where Vdz is zone discharge airflow. Note: For single-zone and single-supply systems, Ep is 1.0. A1.3 System Ventilation Efficiency. The system ventilation efficiency shall equal the lowest zone ventilation efficiency among all ventilation zones served by the air handler, in accordance with Equation A-8. Ev = minimum (Evz) (A-8) A2. ALTERNATIVE CALCULATIONS Mass or flow balance equations for multiple-zone systems may be used to determine system ventilation efficiency and other design parameters, provided that they result in outdoor air intake airflow (Vot ) that is within 5% of the airflow value obtained using the system ventilation efficiency (Ev) calculated using Equation A-8 or they more accurately represent a particular system configuration. A3. DESIGN PROCESS The system ventilation efficiency and therefore the outdoor air intake flow for the system (Vot) determined as part of the design process are based on the design and minimum expected supply air flows to individual ventilation zones as well as the design outdoor air requirements to the zones. For VAV system design purposes, zone ventilation efficiency (Evz) for each ventilation zone shall be found using the minimum expected zone primary airflow (Vpz) and using the highest expected system primary airflow (Vps) at the design condition analyzed. Note: Increasing the zone supply air flow values during the design process, particularly to the critical zones requiring the highest fraction of outdoor air, reduces the system outdoor air intake flow requirement determined in the calculation. 225

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A3.1 Selecting Zones for Calculation. Zone ventilation efficiency (Evz) shall be calculated for all ventilation zones. Exception: Since system ventilation efficiency (Ev) is determined by the minimum value of the zone ventilation efficiency (Evz), in accordance with Equation A-8, calculation of Evz is not required for any ventilation zone that has an Evz value that is equal to or larger than that of the ventilation zone for which a calculation has been done. Note: The value of Evz for a ventilation zone will be equal to or larger than that for another ventilation zone if all of the following are true relative to the other ventilation zone: a. Floor area per occupant (Az/Pz) is no lower b. Minimum zone discharge airflow rate per unit area (Vdz /Az) is no lower c. Primary air fraction (Ep) is no lower d. Zone air distribution effectiveness (Ez) is no lower e. Area outdoor air rate (Ra) is no higher f. People outdoor air rate (Rp) is no higher Example: In office buildings, it is generally only necessary to calculate Evz for one typical interior ventilation zone, since the parameters listed above are generally equal for all interior spaces. If overhead supply air is used to heat the perimeter, it is generally also necessary to calculate Evz for the perimeter zone with the lowest expected primary or discharge airflow rate per unit area. No other calculations for Evz are typically necessary, even if the building has 1000 ventilation zones, provided the ventilation for any conference rooms or non-office occupancy zones are separately calculated.

Ventilation

A4. SYMBOLS Az D

= =

Ep

=

Er

=

Ev

=

Evz

=

Ez

=

Fa

=

Fb

=

Fc

=

Ps

=

Pz Ra Rp Vbz Vdz

= = = = =

Vot Vou Voz

= = =

Zone Floor Area: The net occupiable floor area of the ventilation zone ft2. Occupant Diversity: The ratio of the system population to the sum of the zone populations. Primary Air Fraction: The fraction of primary air in the discharge air to the ventilation zone. Secondary Recirculation Fraction: In systems with secondary recirculation of return air, the fraction of secondary recirculated air to the zone that is representative of average system return air rather than air directly recirculated from the zone. System Ventilation Efficiency: The efficiency with which the system distributes air from the outdoor air intake to the breathing zone in the ventilation-critical zone, which requires the largest fraction of outdoor air in the primary air stream. Note: Ev may be determined in accordance with Section 6.2.5.2 or Section A1. Zone Ventilation Efficiency: The efficiency with which the system distributes air from the outdoor air intake to the breathing zone in any particular ventilation zone. Zone Air Distribution Effectiveness: A measure of the effectiveness of supply air distribution to the breathing zone. Note: Ez is determined in accordance with Section 6.2.2.2. Supply Air Fraction: The fraction of supply air to the ventilation zone that includes sources of air from outside the zone. Mixed Air Fraction: The fraction of supply air to the ventilation zone from fully mixed primary air. Outdoor Air Fraction: The fraction of outdoor air to the ventilation zone that includes sources of air from outside the zone. System Population: The simultaneous number of occupants in the area served by the ventilation system. Zone Population: See Section 6.2.2.1. Area Outdoor Air Rate: See Section 6.2.2.1. People Outdoor Air Rate: See Section 6.2.2.1. Breathing Zone Outdoor Airflow: see Section 6.2.2.1. Zone Discharge Airflow: The expected discharge (supply) airflow to the zone that includes primary airflow and secondary recirculated airflow, cfm. Outdoor Air Intake Flow: See Sections 6.2.3, 6.2.4, 6.2.5.4. Uncorrected Outdoor Air Intake: See Section 6.2.5.3. Zone Outdoor Airflow: See Section 6.2.2.3.

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Vps

=

Vpz Xs

=

Zpz

=

=

System Primary Airflow: The total primary airflow supplied to all zones served by the system from the air-handling unit at which the outdoor air intake is located. Zone Primary Airflow: See Section 6.2.5.1. Average Outdoor Air Fraction: At the primary air handler, the fraction of outdoor air intake flow in the system primary airflow. Primary Outdoor Air Fraction: The outdoor air fraction required in the primary air supplied to the ventilation zone prior to the introduction of any secondary recirculation air.ed the ventilation for any conference rooms or non-office occupancy zones are separately calculated.

Ventilation

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Table 13.6 Ventilation Design Parameters for Health Care Facilities [Std 170-2008, Tbl 7-1]

Ventilation

Function of Space Surgery and Critical Care Classes B and C operating rooms, (m), (n), (o) Operating/surgical cystoscopic rooms, (m), (n) (o) Delivery room (Caesarean) (m), (n), (o) Substerile service area Recovery room Critical and intensive care Wound intensive care (burn unit) Newborn intensive care Treatment room (p) Trauma room (crisis or shock) (c) Medical/anesthesia gas storage (r) Laser eye room ER waiting rooms (q) Triage ER decontamination Radiology waiting rooms (q) Class A Operating/Procedure room (o), (d) Inpatient Nursing Patient room (s) Toilet room Newborn nursery suite Protective environment room (f), (n), (t) AII room (e), (n), (u) AII isolation anteroom (t) (u) Labor/delivery/recovery/postpartum (LDRP) (s) Labor/delivery/recovery (LDR) (s) Corridor Skilled Nursing Facility Resident room Resident gathering/activity/dining Physical therapy Occupational therapy Bathing room Radiology (v) X-ray (diagnostic and treatment) X-ray (surgery/critical care and catheterization) Darkroom (g)

Pressure MiniRelationship mum to Adjacent Outdoor Areas (n) ach

Mini- All Room Air Recircu. mum AirExhausted by Means of Total Directly to Room Units ach Outdoors (j) (a)

RH Design (k), Temp. (l), % °F

Positive

4

20

N/R

No

30–60

68–75

Positive

4

20

N/R

No

30–60

68–75

Positive

4

20

N/R

No

30–60

68–75

N/R N/R Positive Positive Positive N/R Positive Negative Positive Negative Negative Negative Negative

2 2 2 2 2 2 3 N/R 3 2 2 2 2

6 6 6 6 6 6 15 8 15 12 12 12 12

N/R N/R N/R N/R N/R N/R N/R Yes N/R Yes Yes Yes Yes

No No No No No N/R No N/R No N/R N/R No N/R

N/R 30–60 30–60 40–60 30–60 30–60 30–60 N/R 30–60 max 65 max 60 N/R max 60

N/R 70–75 70–75 70–75 70–75 70–75 70–75 N/R 70–75 70–75 70–75 N/R 70–75

Positive

3

15

N/R

No

30–60

70–75

N/R Negative N/R

2 N/R 2

6 10 6

N/R Yes N/R

N/R No No

max 60 N/R 30–60

70–75 N/R 72–78

Positive

2

12

N/R

No

max 60

70–75

Negative N/R

2 N/R

12 10

Yes Yes

No No

max 60 N/R

70–75 N/R

N/R

2

6

N/R

N/R

max 60

70–75

N/R N/R

2 N/R

6 2

N/R N/R

N/R N/R

max 60 N/R

70–75 N/R

2 4 2 2 N/R

2 4 6 6 10

N/R N/R N/R N/R Yes

N/R N/R N/R N/R N/R

N/R N/R N/R N/R N/R

70–75 70–75 70–75 70–75

N/R N/R Negative N/R Negative

70–75

N/R

2

6

N/R

N/R

max 60

72–78

Positive

3

15

N/R

No

max 60

70–75

Negative

2

10

Yes

No

N/R

N/R

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Table 13.6 Ventilation Design Parameters for Health Care Facilities [Std 170-2008, Tbl 7-1] (Continued)

Function of Space

Pressure MiniRelationship mum to Adjacent Outdoor Areas (n) ach

Mini- All Room Air Recircu. mum AirExhausted by Means of Total Directly to Room Units ach Outdoors (j) (a)

RH Design (k), Temp. (l), % °F

Negative

2

12

Yes

No

N/R

68–73

Negative Negative Negative Negative Negative Negative Negative Negative Negative Negative Negative Positive Negative Negative Positive N/R Positive Positive Negative N/R Negative Negative

2 2 2 2 2 2 2 2 2 2 2 2 2 N/R 2 2 2 2 2 2 2 2

6 6 6 6 10 6 6 6 6 6 10 4 12 10 4 6 4 15 10 6 6 6

N/R Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes N/R Yes Yes N/R N/R N/R N/R Yes N/R N/R N/R

No No No No No No No No No No No No No No N/R N/R N/R No No N/R N/R N/R

N/R N/R N/R N/R N/R N/R N/R N/R N/R N/R N/R N/R N/R N/R N/R max 60 max 60 30-60 N/R max 60 N/R Max 65

70–75 70–75 70–75 70–75 N/R 70–75 70–75 70–75 70–75 70–75 70–75 70–75 68–75 70–75 N/R 70–75 70–75 68–73 N/R 70–75 72–78

Sterilizing Sterilizer equipment room

Negative

N/R

10

Yes

No

N/R

N/R

2 2 2

6 4 4

Yes N/R N/R

No No N/R

N/R max 60 max 60

72–78 72–78

Central Medical and Surgical Supply Soiled or decontamination room Negative Clean workroom Positive Sterile storage Positive

Ventilation

Diagnostic and Treatment Bronchoscopy, sputum collection, and pentamidine administration (n) Laboratory, general (v) Laboratory, bacteriology (v) Laboratory, biochemistry (v) Laboratory, cytology (v) Laboratory, glasswashing Laboratory, histology (v) Laboratory, microbiology (v) Laboratory, nuclear medicine (v) Laboratory, pathology (v) Laboratory, serology (v) Laboratory, sterilizing Laboratory, media transfer (v) Autopsy room (n) Nonrefrigerated body-holding room (h) Pharmacy (b) Examination room Medication room Endoscopy Endoscope cleaning Treatment room Hydrotherapy Physical therapy

72–78

72–78

Service Food preparation center (i) Warewashing Dietary storage Laundry, general Soiled linen sorting and storage Clean linen storage Linen and trash chute room Bedpan room Bathroom Janitor’s closet

N/R Negative N/R Negative Negative Positive Negative Negative Negative Negative

2 N/R N/R 2 N/R N/R N/R N/R N/R N/R

10 10 2 10 10 2 10 10 10 10

N/R Yes N/R Yes Yes N/R Yes Yes Yes Yes

No No No No No N/R No No No No

N/R N/R N/R N/R N/R N/R N/R N/R N/R N/R

72–78 N/R 72–78 N/R N/R 72–78 N/R N/R 72–78 N/R

Support Space Soiled workroom or soiled holding Clean workroom or clean holding Hazardous material storage

Negative Positive Negative

2 2 2

10 4 10

Yes N/R Yes

No N/R No

N/R N/R N/R

N/R N/R N/R

Note: N/R = no requirement

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Operation and Maintenance Provide an O&M manual together with final system design drawings, updated and maintained on site. Table 13.7 Minimum Maintenance Activity and Frequency Item Filters and air cleaning devices Outdoor air dampers and actuators Humidifiers

Ventilation

Dehumidification coils

Activity Minimum Frequencya Code A According to O&M Manual Every three months or in accordance with B O&M Manual Every three months of use or in accordance C with O&M Manual Regularly when it is likely that D dehumidification occurs but no less than once per year or as specified in the O&M Manual

Drain pans and other adjacent surfaces subject to wetting

D

Once per year during cooling season or as specified in the O & M Manual

Outdoor air intake louvers, bird screens, mist eliminators, and adjacent areas

E

Every six months or as specified in the O&M Manual

Sensors used for dynamic minimum outdoor air control

F

Every six months or periodically in accordance with O&M Manual

Air-handling systems except for units under 2000 cfm

G

Once every five years

Cooling towers

H

In accordance with O&M Manual or treatment system provider

Floor drains located in plenums or rooms that serve as air plenums Equipment/component accessibility Visible microbial contamination Water intrusion or accumulation

I

Periodically according to O&M Manual

J K K

Activity Code: A Maintain according to O & M Manual. B Visually inspect or remotely monitor for proper function. C Clean and maintain to limit fouling and microbial growth. D Visually inspect for cleanliness and microbial growth and clean when fouling is observed. E Visually inspect for cleanliness and integrity and clean when necessary. F Verify accuracy and recalibrate or replace as necessary. G Measure minimum quantity of outdoor air. If measured minimum air flow rates are less than 90% of the minimum outdoor air rate in the O & M Manual, they shall be adjusted or modified to bring them above 90% or shall be evaluated to determine if the measured rates are in conformance with this standard. H Treat to limit the growth of microbiological contaminants. I Maintain to prevent transport of contaminants from the floor drain to the plenum. J Keep clear the space provided for routine maintenance and inspection around ventilation equipment. K Investigate and rectify. aMinimum

frequencies may be increased or decreased if indicated in the O & M Manual.

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14.

ENERGY-CONSERVING DESIGN

Sustainability Recognition of the impact of the building industry’s activities on the earth’s ecosystem is changing the way it approaches the design, construction, operation, maintenance, reuse, and demolition of what it creates—namely addressing the environmental and long-term economic consequences of its actions. While this sustainable design ethic—or sustainability—covers things beyond the purview of HVAC&R, design for the efficient use of energy resources is a key element of sustainable design. The basic approach to energy-efficient design is reducing loads and required power, improving transport systems, and providing efficient components and “intelligent” controls. This includes understanding the relationship between energy and power, maintaining simplicity, using self-imposed budgets, and applying energy-smart design practices. An example of a budget designers have set for themselves for office buildings in a typical mid-USA climate: Installed lighting

0.8 W/ft2

Thermal power

20 Btu/h·ft2

Space sensible cooling

15 Btu/h·ft2

Hydronic system head

65 ft water

Space heating load

10 Btu/h·ft2

Water chiller (water-cooled) 0.50 kW/ton

Fan system pressure

3.0 in. water

Chilled water auxiliaries

0.12 kW/ton

Air circulation

1 cfm/ft2

Annual electric energy

15 kW/ft2·y

Overall electric power

3.0 W/ft2

Annual thermal energy

5 Btu/ft2·y°F·day

Then, as design proceeds, compare with budget: 1. Minimize impact of building’s functional requirements—to reduce, redistribute, or shift (delay) loads. 2. Minimize loads—look at peak and part-load operation. 3. Maximize subsystem efficiency—including opportunities to reclaim, redistribute, and store energy for future use. 4. Study alternative ways to integrate subsystems into the building—use easily understood design solutions to foster simplicity of operation.

HVAC&R System Design •

• • •

• • • • • •

Energy-Conserving Design

•

Consider separate systems to serve areas expected to operate on widely different schedules or design conditions. Arrange systems so spaces with relatively constant and weather-independent loads are served by systems separate from systems serving perimeter spaces. Sequence supply of cooling and heating to prevent simultaneous operation of heating and cooling systems to the same space. Provide controls to allow operation in an occupied mode and an unoccupied mode. Where diurnal temperature swings and humidity levels permit, consider coupling air distribution and building mass to allow nighttime cooling to reduce requirement of daytime mechanical cooling. Where climate allows, consider mixed-mode systems of HVAC and natural ventilation. Select energy conversion devices matched to load increments. Select the most efficient equipment practical at both design and part-load operating conditions. Seriously consider life-cycle purchasing technique for large power devices. Transport energy by the most energy-efficient means. Provide intelligent control system that provides information to operators and managers.

Summary In designing HVAC&R systems, the need to address immediate issues such as economics, performance, and space constraints should not prevent designers from fully considering different energy sources. Consider the viability and dependability of energy resources for the long-term operation of the building. Energy standards and legislation represent only the minimum that can be achieved; strive to better utilize energy. 231

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Energy Efficiency Standards ANSI/ASHRAE/IES Standard 90.1-2010, Energy Standard for Buildings Except Low-Rise Residential Buildings The standard includes minimum energy-efficient requirements for new buildings or portions of buildings and their systems; new systems and equipment in existing buildings. There is a strong move to provide considerably more energy savings than required by this standard. The standard has had frequent addenda and is revised every three years. Prescriptive Path for Compliance Highlights Section 5. Building Envelope: Tables in the standard cover eight climate zones (see the following map from Appendix B) for non-residential, residential, and semi-heated occupancies for minimum allowable insulating value of envelope elements and maximum allowable solar heat gain of fenestration. Section 6. HVAC; minimum equipment efficiencies. Required controls. Allowable fan power for supply air systems. Hydronic systems with pump power exceeding 10 hp and having control valves that change the flow rate with load shall be designed for variable flow, capable of reducing flow 50%. Heat rejection equipment fans with 7.5 hp motor or larger shall automatically be able to reduce fan speed with load to 2/3 or less of design. Exhaust energy shall be 50% recoverable for systems with both supply of 5000 cfm or greater and minimum 70% outdoor air. Heat recovery systems are required for service water heating systems where the facility operates 24 hours a day, heat rejection exceeds 6,000,000 Btu/h, and service water heating load exceeds 1,000,000 Btu/h. When heating unenclosed spaces, radiant heating shall be used. Section 7. Service water heating—minimum equipment efficiencies. Section 8. Power: Feeder conductors sized for maximum voltage drop of 2% at design load; branch circuit conductors 3%. Section 9. Lighting: Limitations on lighting power densities, controls required. Section 10. Other equipment: Minimum allowable electric motor efficiencies. Alternative to Prescriptive Methods of Compliance Section 11. Energy cost budget method. ASHRAE Standard 90.2-2007, Energy Efficient Design of Low-Rise Residential Buildings Prescriptive minimum requirements for envelope and equipment with alternate annual energy cost method of compliance. ASHRAE Standard 100-2006, Energy Conservation in Existing Buildings Energy-Conserving Design

A building or a complex of buildings complies when the following requirements have been met and recorded on Form A of the standard and the party determining compliance has (1) conducted an energy survey as required by the standard in Section 5, (2) stated in writing that the operation and maintenance requirements in Section 5 have been met, and (3) has stated in writing that building and equipment modifications in Section 7 have been met. More stringent and more detailed requirements can be expected in future editions of the standard.

232

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Energy-Conserving Design

Figure 14.1 Climate Zones for United States Locations [Std 90.1-2010, Fig B-1] 233

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a Expressed

Efficiency

25% 250 to 300% Constant 95% High

Constant

60%

Medium

3450 to 1725

125 to 150% 250 to 300%

3450 to 1725

None 0.05 to 5

0.05 to 0.5

Permanent Split-Capacitor

Centrifugal switch

Split-Phase

Medium

65%

Constant

250 to 350% 250 to 300%

3450 to 1725

0.05 to 5

Centrifugal switch

Capacitor-Start Induction-Run

High

95%

Constant

250% 250%

3500 to 1750

0.05 to 5

Centrifugal switch

Capacitor-Start Capacitor-Run

Low

60%

Constant or adjustable

25% 125%

3100 to 1550

0.01 to 0.25

None

Shaded-Pole

Table 15.1 Characteristics of AC Motors (Nonhermetic) [2012S, Ch 45, Tbl 4]

as percent of rated horsepower torque.

Full-Load Power Factor

Speed Classification

Torquea Locked Rotor Breakdown

Full-Load Speeds at 60-Hz (Two-Pole, Four-Pole)

Ratings, hp

Starting Method

Speed Torque Curves

Connection Diagram

Electrical


High-Medium

80%

Constant

150 to 350% 250 to 350%

3500 to 1750

0.5 and up

Motor controller

Polyphase, 60-Hz

15. ELECTRICAL


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Table 15.2 Recommended Starter Size Three Phase

Horsepower 230 V 460 V

Motor Full-Load Amperes

Three-Phase AC SquirrelCage and Wound-Rotor (Induction Type)

Recommended Starter Size Single Phase

Single-Phase AC

230 V

115 V

200 V

230 V

Horsepower

1/6

00

4.4

2.5

2.2

1/6

1/4

00

5.8

3.3

2.9

1/4

00

9.8

5.6

4.9

1/2 3/4

200 V

230 V

2.3

2

460 V

1/2

00

00

1

3/4

00

00

3.2

2.8

1.4

00

13.8

7.9

6.9

1

00

00

4.1

3.6

1.8

00

16

9.2

8

1

1.5

00

00

6.0

5.2

2.6

0

20

11.5

10

1.5

2

0

00

7.8

6.8

3.4

0

24

13.8

12

2

3

0

0

11.0

9.6

4.8

1

34

19.6

17

3

5

1

0

17.5

15.2

7.6

1

56

32.2

28

5

7.5

1

1

25.3

22

11

2

80

46

40

7.5

10

2

1

32.2

28

14

2

100

57.5

50

10

15

2

2

48.3

42

21

3

20

3

2

62.1

54

27

20

25

3

2

78.2

68

34

25

30

3

3

92

80

40

30

40

4

3

119.6

104

52

40

50

4

3

149.5

130

65

50

60

5

4

177.1

154

77

60

75

5

4

220.8

192

96

75

100

5

4

285.2

248

124

100

125

6

5

358.8

312

156

125

150

6

5

414

360

180

150

200

6

5

552

480

240

200

15

Values are for motors with normal torque characteristics running at usual belted speeds.

Table 15.3

Useful Electrical Formulas

To Find

Direct Current

Single Phase

Three Phase

Amperes when horsepower is known

hp  746 --------------------E

hp  746 ----------------------EF

hp  746 ---------------------------------------1.73  E    F

kW  1000 -------------------------E

kW  1000 -------------------------EF

kW  1000 -----------------------------1.73  E  F

Amperes when kilowatts is known

kVA  1000 ----------------------------1.73  E

IEF --------------------1000

I  E  1.73  F -------------------------------------1000

Kilowatts

IE --------------------746

IE -----------1000 IEF ------------------------------746

I  E  1.73 ---------------------------1000 I  E  1.73    F -----------------------------------------------746

kVA Horsepower—(output)

1 = amperes; E = volts;  = efficiency expressed as decimal; F = power factor; kW = kilowatts; kVA = kilovolt-amperes; hp = horsepower.

Electrical

kVA  1000 ----------------------------E IE -----------1000

Amperes when kVA is known

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Motor Controllers Three-phase constant-speed induction motor controllers are usually full-voltage except when the starting current must be reduced in larger motors to meet power system limitations; such motor controllers may be of various row types. All are used for starting and stopping the motor and include overcurrent protection.

Variable-Speed Drives (VSDs) By far the most energy-efficient means of varying flow of fans and pumps driven by electric motors are VSDs. Their application involves careful consideration of their effects (here VSD is considered synonymous with variable-frequency drive [VFD], pulse-width modulated drive [PWM drive], adjustable-speed drive [ASD], and adjustable-frequency drive [AFD].) A VSD consists of a pulse-width-modulation controller with insulated-gate bipolar transistors (IGBTs) and an induction motor. The IGBT changes the characteristics of waveforms applied to a motor due to the speed at which the IGBT cycles on and off. At switching speed up to 20 k Hz the impedance in the connecting cable is far less than the motor impedance, particularly for small motors, causing pulse reflectance at the motor terminals to form damaging high voltage. NEMA motor standard MG1 states PWM drive limits and establishes a peak of 1600 V and a minimum rise time of 0.1 s for motors rated less than 600 V. Typical manufacturer maximum voltage withstand levels range from 1000 V to 1800 V. When specifying motors for operation on VSDs, the voltage withstand level based on the dv/dt of the drive and the known cable distance should be specified. Harmonics caused by the portion of a VSD converting line power LDC affect input lines and are termed line-side harmonics. Output line harmonics are caused solely by the inverter section of the VSD and are known as load side or motor harmonics. Generally, PWM drives containing internal bus reaction or three-phase AC line reactors do not cause interference with other electrical equipment. There may be problems when a VSD is switched onto a standby generator, or when power factor correction capacitors are used.

Electrical

Figure 15.1 Motor Voltage Peak and dv/dt Limits (Reprinted from NEMA Standard MG 1, Part 30, by permission of the National Electrical Manufacturers Association)

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Photovoltaic Systems

Figure 15.2 Representative Current-Voltage and Power-Voltage Curves for Photovoltaic Device [2012S, Ch 37, Fig 30]

Photovoltaic (PV) cells convert sunlight directly into electricity. A photovoltaic cell consists of an active photovoltaic material, metal grids, antireflection coatings, and supporting material; a two-terminal device with positive and negative leads. Current depends on the amount of light on the cell and the external voltage applied. When the cell is short-circuited, current ISC is at maximum and voltage across the cell is zero. When the PV circuit is open, voltage is at maximum VOC and current is zero. Between open and short circuit, power output is greater than zero. By illuminating and loading a PV cell with voltage equal to the cell’s Vmax, output power is maximized. The cell can be loaded by using resistance loads, electronic loads, or batteries. An additional parameter, fill factor FF can be calculated such that Pmax = ISC VOC FF

Electrical

Typical parameters of a cell are current density JSC = 206 mA/in.2; Va = 0.58 V; Vmax = 0.47 V; FF = 0.72; and Pmax = 2273 mW. A PV module is comprised of a series of cells to provide operating voltage around 15 V, factory-encapsulated, with a junction box for wiring to other modules or other electrical equipment. Deep-cycle lead acid batteries are commonly wired so power can be supplied at night or whenever the PV system cannot meet demand. Battery charge controllers regulate power from the modules to prevent battery overcharging. Inverters convert the direct current to alternating current. Mounting structures and wiring complete a PV system.

237

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Sorbents and Desiccants

16.

SORBENTS AND DESICCANTS

Sorbents are materials that have an ability to attract and hold other gases or liquids. They can be used to attract gases or liquids other than water vapor, a characteristic that makes them very useful in chemical separation processes. Desiccants are a subset of sorbents; they have a particular affinity for water. Wood, natural fibers, clays, and many synthetic materials attract and release moisture as commercial desiccants do, but they lack the holding capacity. Furthermore, commercial desiccants continue to attract moisture even when the surrounding air is quite dry. All desiccants attract moisture until they reach equilibrium with the surrounding air. Moisture is usually removed from the desiccant by regeneration, heating it to temperatures between 120 and 500°F and exposing it to a scavenger airstream. After the desiccant dries, it must be cooled so that it can attract moisture once again. Sorption always generates sensible heat equal to the latent heat of the water vapor taken up by the desiccant plus an additional heat of sorption that varies between 5 and 25% of the latent heat of the water vapor. This heat is transferred to the desiccant and to the surrounding air. Attracting and holding moisture is described as either adsorption or absorption. Adsorption does not change the desiccant, except by the addition of the weight of water vapor. Absorption, on the other hand, changes the desiccant. An example of an absorbent is table salt, which changes from a solid to a liquid as it absorbs moisture. The economics of desiccant operation depend on the energy cost of moving a given material through this cycle. The dehumidification of air (loading the desiccant with water vapor) generally proceeds without energy input other than fan and pump costs. The major portion of energy is invested in regenerating the desiccant (moving from point 2 to point 3) and cooling the desiccant (point 3 to point 1). In commercial equipment, desiccants last from 10,000 to 100,000 h and longer before replacement. Two mechanisms cause loss of desiccant capacity: (1) change in sorption characteristics through chemical reactions with contaminants and (2) loss of effective surface area through clogging or hydrothermal degradation. Liquid absorbents are more susceptible to chemical reaction with airstream contaminants than are solid. Solid adsorbents tend to be less chemically reactive and more sensitive to clogging, a function of the type and quantity of particulate material in the airstream. In air-conditioning applications, desiccant equipment is designed to minimize the need for desiccant replacement in much the same way that vapor compression cooling systems are designed to avoid the need for compressor replacement.

Figure 16.1 Desiccant Cycle [2013F, Ch 32, Fig 3] 238

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Figure 16.2 Flow Diagram for Liquid-Absorbent Dehumidifier [2012S, Ch 24, Fig 2]

Figure 16.3 Flow Diagram for Liquid-Absorbent Unit with Extended Surface AIr Contact Media [2012S, Ch 24, Fig 3]

Figure 16.4

Typical Solid Rotary Dehumidification Unit [2012S, Ch 24, Fig 7] 239

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Desiccant Dehumidification Both liquid and solid desiccants may be used in equipment designed for the drying of air and gases. Desiccant performance depends on the equipment, the characteristics of the desiccants, initial temperature and moisture content of the gas to be dried and reactivation methods. Factory-assembled units are available up to a capacity of about 80,000 cfm. In liquid-desiccant dehumidification, moisture is absorbed from or desorbed into the air because of the difference in water vapor pressure between the air and the desiccant solution. A higher solution concentration results in a lower water vapor pressure. A lower solution temperature results in a lower water vapor pressure. By controlling temperature and concentration of the desiccant solution, the conditioner can deliver air at precisely controlled temperature and humidity. The unit dehumidifies the air during humid weather and humidifies it during dry weather. When dehumidifying, water is automatically removed from the liquid desiccant in the regenerator to maintain the desiccant at the proper concentration. When the conditioner is being used to humidify the air, the regenerator fan and desiccant solution pump are typically stopped to save energy. Because the conditioner and regenerator are separate units, they can be in different locations and connected by piping. This can substantially lower ductwork cost and required mechanical space. Commonly, a single regenerator services several conditioner units. The regenerator can be sized to match the dehumidification load of the conditioner unit or units. Regenerator capacity is affected by regenerator heat source temperatures; higher source temperatures produce greater capacity. Regenerator capacity is also affected by desiccant concentration; higher concentrations result in reduced capacity. The relative humidity of the air leaving the conditioner is practically constant for a given desiccant concentration, so the regenerator capacity can be shown as a function of delivered air relative humidity and regenerator heat source temperature. A typical rotary solid desiccant dehumidifier can have a bed of beads of granular material or it can be finely divided and impregnated throughout a structured media resembling corrugated cardboard rolled into a drum, so air can pass freely through flutes aligned lengthwise through the drum. The desiccant can be either a single material, such as silica gel, or a combination, such as dry lithium chloride mixed with zeolites. The wide range of applications for dehumidification systems requires this flexibility to minimize operating and installed costs. Performance variables for system design for process air and reactivation air include • inlet air temperature, • moisture content, and • velocity at the face of the desiccant bed. For silica gel, structured-bed fluted media, with the bed depth 16 in.in the direction of airflow, the ratio of process air to reactivation air is approximately 3:1. The process air enters the machine at normal comfort conditions of 70°F, 50% rh.

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Model of Typical Rotary Solid Desiccant Dehumidifier Sorbents and Desiccants

Figure 16.5 Effect of Changes in Process Air Velocity on Dehumidifier Outlet Moisture [2012S, Ch 24, Fig 8]

Figure 16.6

Effect of Changes in Process Air Inlet Moisture on Dehumidifier Outlet Moisture [2012S, Ch 24, Fig 9]

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Figure 16.7 Effect of Changes in Reactivation Air Inlet Temperature on Dehumidifier Outlet Moisture [2012S, Ch 24, Fig 10]

Figure 16.8 Effect of Changes in Process Air Inlet Moisture on Dehumidifier Outlet Temperature [2012S, Ch 24, Fig 11] 242

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Figure 16.9 Effect of Changes in Reactivation Air Inlet Temperature on Dehumidifier Outlet Temperature [2012S, Ch 24, Fig 12]

Figure 16.10

Typical Performance Data for Rotary Solid Desiccant Dehumidifier [2012S, Ch 24, Fig 13]

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Combined Heat & Power Systems

17.

COMBINED HEAT AND POWER SYSTEMS

Combined heat and power (CHP) is the simultaneous production of electrical or mechanical energy (power) and useful thermal energy from a single energy source. Recovered thermal energy from fuel used in reciprocating engines, turbines, or fuel cells. CHP can operate on a topping, bottoming, or combined cycle. Figure 17.1 shows an example of topping and bottoming configurations. In a topping cycle, energy from the fuel generates shaft or electric power first, and thermal energy from the exiting stream is recovered for other applications such as process heat for cooling or heating systems. In a bottoming cycle, shaft or electric power is generated last from thermal energy left over after higher-level thermal energy has been used to satisfy thermal loads. A typical topping cycle recovers heat from operation of a prime mover and uses this thermal energy for the process (cooling and/or heating). A bottoming cycle recovers heat from the process to generate power. A combined cycle uses thermal output from a prime mover to generate additional shaft power (e.g., combustion turbine exhaust generates steam for a steam turbine generator). Grid-isolated CHP systems, in which electrical output is used on site to satisfy all site power and thermal requirements, are referred to as total energy systems. Grid-parallel CHP systems, which are actively tied to the utility grid, can, on a contractual or tariff basis, exchange power with or reduce load on (thus reducing capacity demand) the public utility. This may eliminate or lessen the need for redundant on-site back-up generating capacity and allows operation at maximum thermal efficiency when satisfying the facility’s thermal load; this may produce more electric power than the facility needs. Table 17.1

Applications and Markets for DG/CHP Systems [2012S, Ch 7, Tbl 1]

DG Technologies Reciprocating engines: 50 kW to 16 MW Gas turbines: 500 kW to 50 MW Steam turbines: 500 kW to 100 MW Microturbines: 30 to 500 kW Fuel cells: 5 kW to 2 MW

CusBaseLoad Demand tomer PreStandby Power Response Peak mium Power Only Peaking Shaving Power X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X X

X

Utility Grid Support CHP Applicable Market Sectors

X X

X

Source: Adapted from NREL (2003).

Figure 17.1

X

X

Commercial buildings, institutional, industrial, utility grid (larger units), waste fuels Large commercial, institutional, industrial, utility grid, waste fuels Institutional buildings/campuses, industrial, waste fuels Commercial buildings, light industrial, waste fuels Residential, commercial, light industrial

DG = distributed generation (on-site power generation)

CHP Cycles [2012S, Ch 7, Fig 1]

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Engine Sizing Table 17.2

Fuel Consumption Rates [2004S, Ch 7, Tbl 11]

Fuel

Range of Consumption, Btu/hph 7000 to 9000 10,000 to 14,000

Compression Ratio

Gas Consumption, Btu/hph

10.5:1 10.5:1 7.5:1

8,100 9,200 10,250

Table 17.3 Percent Minimum Engine Reserves for Air Conditioning and Refrigeration [2004S, Ch 7, Tbl 12] Altitude, ft Sea level 1000 2000 3000 4000 5000 10,000

Naturally Aspirated Air Conditioning Refrigeration 15 20 12 17 10 14 10 11 10 10 10 10 10 10

Table 17.4 Room Air Temperature Rise, a °F 10 20 30

Turbocharged Aftercooled Air Conditioning Refrigeration 20 30 18 28 16 26 14 24 12 22 10 20 10 10


Fuel oil Gasoline Typical Consumption for Different Types of Gas Engines Turbocharged Naturally aspirated Naturally aspirated

Heating Value, Btu/gal 137,000 to 156,000 130,000

Ventilation Air for Engine Equipment Rooms [2012S, Ch 7, Tbl 10] Airflow, cfm/hp Muffler and Exhaust Pipe b

Muffler and Exhaust Pipe c

Air- or Radiator-Cooled Engine d

140 70 50

280 140 90

550 280 180

a Exhaust minus inlet. b Insulated or enclosed in ventilated c Not insulated. d Heat discharged in engine room.

duct.

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Table 17.5

Recommended Engine Maintenance [2012S, Ch 7, Tbl 13] Procedure


1. Take lubricating oil sample 2. 3. 4. 5. 6. 7. 8.

Change lubricating oil filters Clean air cleaners, fuel Clean fuel filters Change lubricating oil Clean crankcase breather Adjust valves Lubricate tachometer, fuel priming pump, and auxiliary drive bearings 9. Service ignition system; adjust breaker gap, timing, spark plug gap, and magneto 10. Check transistorized magneto 11. Flush lubrication oil piping system 12. Change air cleaner 13. Replace turbocharger seals and bearings 14. Replace piston rings, cylinder liners (if applicable), connecting rod bearings, and cylinder heads; recondition or replace turbochargers; replace gaskets and seals 15. Same as item 14, plus recondition or replace crankshaft; replace all bearings

Figure 17.2

Hours Between Procedures Diesel Engine Gas Engine Once per month plus Once per month plus once at each oil change once at each oil change 350 to 750 500 to 1000 350 to 750 350 to 750 500 to 750 n.a. 500 to 1000 1000 to 2000 350 to 700 350 to 750 1000 to 2000 1000 to 2000 1000 to 2000 1000 to 2000 (fuel pump n.a.) n.a. 1000 to 2000 n.a. 3000 to 5000

6000 to 8000 3000 to 5000

2000 to 3000 4000 to 8000 8000 to 12,000

2000 to 3000 4000 to 8000 8000 to 12,000

24,000 to 36,000

24,000 to 36,000

Performance Curve for Typical 100 Ton, Gas-Engine-Driven, Reciprocating Chiller [2012S, Ch 7, Fig 64]

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Figure 17.3 Heat Balance for Naturally Aspirated Engine [2012S, Ch 7, Fig 45]

Figure 17.4 Heat Balance for Turbocharged Engine [2012S, Ch 7, Fig 46] 247

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Figure 17.5 CHP Power and Heating Energy Boundary Diagram [2012S, Ch 7, Fig 6]

Table 17.6 Temperatures Normally Required for Various Heating Applications [2012S, Ch 7, Tbl 17] Application Absorption refrigeration machines Space heating Water heating (domestic) Process heating Evaporation (water) Residual fuel heating Auxiliary power producers, with steam turbines or binary expanders Table 17.7

Temperature, °F 190 to 245 120 to 250 120 to 200 150 to 250 190 to 250 212 to 330 190 to 350

Full-Load Exhaust Mass Flows and Temperatures for Various Engines [2004S, Ch 7, Tbl 6] Type of Engine

Two-cycle Blower-charged gas Turbocharged gas Blower-charged diesel Turbocharged diesel Four-cycle Naturally aspirated gas Turbocharged gas Naturally aspirated diesel Turbocharged diesel Gas turbine, nonregenerative

Mass Flow, lb/bhp·h

Temperature, °F

16 14 18 16

700 800 600 650

9 10 12 13 18 to 48*

1200 1200 750 850 800 to 1050*

*Lower mass flows correspond to more efficient gas turbines. 248

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Figure 17.6

Single-Stage Noncondensing Steam Turbine Efficiency [2012S, Ch 7, Fig 38]

Figure 17.7 Automatic Extraction Turbine CHP System [2012S, Ch 7, Fig 59] Allows extraction of exhaust steam at one or more stations to match exhaust conditions required for various processes.

Table 17.8 Theoretical Steam Rates for Steam Turbines at Common Conditions, lb/kWh [2012S, Ch 7, Tbl 15, Abridged] Exhaust Pressure 150 psig, 366°F, Saturated 2 in. Hg (abs.) 10.52 4 in. Hg (abs.) 11.76 0 psig 19.37 10 psig 23.96 30 psig 33.6 50 psig 46.0 60 psig 53.9 70 psig 63.5 75 psig 69.3

Throttle Steam Conditions 200 psig, 388°F, 250 psig, 500°F, 400 psig, 750°F, Saturated 94°F Superheat 302°F Superheat 10.01 9.07 7.37 11.12 10.00 7.99 17.51 15.16 11.20 21.09 17.90 12.72 28.05 22.94 15.23 36.0 28.20 17.57 40.4 31.10 18.75 45.6 34.1 19.96 48.5 35.8 20.59 249

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Combustion Turbines


Combustion gas turbines are available in sizes from 38 to 644,000 hp, and can burn a wide range of liquid and gaseous fuels. They consist of an air compressor section, a combuster (fuel/air mixing and combustion chamber), and an expanding turbine section. Simple turbine thermal efficiencies range from 28% to 36% (based on fuel higher heating value). Rotating speeds vary from 3600 to 100,000 rpm. Some turbines use regenerators and recuperators as heat exchangers to preheat combustion air, increasing machine efficiency.

Figure 17.8

Simple-Cycle Single-Shaft Turbine [2012S, Ch 7, Fig 22]

Figure 17.10 Temperature-Entropy Diagram for Brayton Cycle [2012S, Ch 7, Fig 21]

Figure 17.9

Simple-Cycle Dual-Shaft Turbines [2012S, Ch 7, Fig 23]

Figure 17.11 Turbine Engine Performance Characteristics [2012S, Ch 7, Fig 24]

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Fuel Cells Fuel cells convert chemical energy of a hydrogen-based fuel directly into electricity without combustion. In the cell, a hydrogen-rich fuel passes over the anode, while an oxygen-rich gas (air) passes over the cathode. Catalysts help split the hydrogen into hydrogen ions and electrons. The hydrogen ions move through an external circuit, thus providing a direct current at a fixed voltage potential. A typical packaged fuel cell power plant consists of a fuel reformer (processor), which generates hydrogen-rich gas from fuel; a power section (stack) where the electrochemical process occurs; and a power conditioner (inverter), which converts the dc power generated in the fuel cell into ac power. Most fuel cell applications involve interconnectivity with the electric grid; thus, the power conditioner must synchronize the fuel cell’s electrical output with the grid. A growing number of fuel cell applications are grid independent to reliably power remote or critical systems.

Phosphoric Acid (PAFC) Commercially available Size range Efficiency (LHV) Efficiency (HHV) Average operating temperature Heat recovery characteristics

Solid Oxide (SOFC)

Molten Carbonate (MCFC)

Proton Exchange Membrane (PEMFC)

No

Yes

Yes

Yes 100 to 200 kW 40% 36%

1 kW to 10 MW 250 kW to 10 MW 500 W to 250 kW 45 to 60% 45 to 55% 30 to 40% 40 to 54% 40 to 50% 27 to 36%

400°F

1800°F

1200°F

200°F

Hot water

Hot water/steam

Hot water, steam

140°F water


Table 17.9 Overview of Fuel Cell Characteristics [2012S, Ch 7, Tbl 14]

Source: Adapted from Foley and Sweetser (2002).

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Figure 17.12 PAFC Cell [2012S, Ch 7, Fig 28]

Figure 17.13 SOFC Cell [2012S, Ch 7, Fig 29]


Figure 17.14 MCFC Cell [2012S, Ch 7, Fig 30]

Figure 17.15


PEMFC Cell [2012S, Ch 7, Fig 31]


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18.

FUELS AND COMBUSTION Table 18.1 Maximum Capacity of Gas Pipe in Cubic Feet per Hour [2013F, Ch 22, Tbl 26]

Nominal Iron Internal Pipe Diameter, Size, in. in.

Length of Pipe, ft 10

20

30

40

50

60

70

80

90

100 125 150 175 200

1/4

0.364

32

22

18

15

14

12

11

11

10

9

8

8

7

6

3/8

0.493

72

49

40

34

30

27

25

23

22

21

18

17

15

14

1/2

0.622

132

92

73

63

56

50

46

43

40

38

34

31

28

26

3/4

0.824

278

190

152

130

115

105

96

90

84

79

72

64

59

55

1

1.049

520

350

285

245

215

195

180

170

160

150

130

120

110

100

1 1/4

1.380

1,050

730

590

500

440

400

370

350

320

305

275

250

225

210

890

760

670

610

320

1.610

1,600 1,100

560

530

490

460

410

380

350

2

2.067

3,050 2,100 1,650 1,450 1,270 1,150 1,050

990

930

870

780

710

650

610

2 1/2

2.469

4,800 3,300 2,700 2,300 2,000 1,850 1,700 1,600 1,500 1,400 1,250 1,130 1,050

980

3

3.068

8,500 5,900 4,700 4,100 3,600 3,250 3,000 2,800 2,600 2,500 2,200 2,000 1,850 1,700

4

4.026

17,50012,000 9,700 8,300 7,400 6,800 6,200 5,800 5,400 5,100 4,500 4,100 3,800 3,500

Note: Capacity is in cubic feet per hour at gas pressures of 0.5 psig or less and a pressure drop of 0.3 in. of water; specific gravity = 0.60. Copyright by the American Gas Association and the National Fire Protection Association. Used by permission of the copyright holder.

Fuels and Combustion

1 1/2

Table 18.2 Typical API Gravity, Density, and Heating Value of Standard Grades of Fuel Oil [2013F, Ch 28, Tbl 6] Grade No.

API Gravity

Density, lb/gal

Heating Value, Btu/gal

1

38 to 45

6.950 to 6.675

137,000 to 132,900

2

30 to 38

7.296 to 6.960

141,800 to 137,000

4

20 to 28

7.787 to 7.396

148,100 to 143,100

5L

17 to 22

7.940 to 7.686

150,000 to 146,800

5H

14 to 18

8.080 to 7.890

152,000 to 149,400

6

8 to 15

8.448 to 8.053

155,900 to 151,300

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Types of Fuel Oils


Fuel oils for heating are broadly classified as distillate fuel oils (lighter oils) or residual fuel oils (heavier oils). ASTM has established specifications for fuel oil properties which subdivide the oils into various grades. Grades No. 1 and 2 are distillate fuel oils. Grades 4,5 (Light), 5 (Heavy), and 6 are residual fuel oils. Specifications for the grades are based on required characteristics of fuel oils for use in different types of burners. The ANSI standard specification for fuel oils is ASTM Standard D396-86. Grade No. 1 is a light distillate intended for vaporizing-type burners. High volatility is essential to continued evaporation of the fuel oil with minimum residue. Grade No. 2 is a heavier (API Gravity) distillate than No. 1. It is used primarily with pressure-atomizing (gun) burners that spray the oil into a combustion chamber. The atomized oil vapor mixed with air and burns. This grade is used in most domestic burners and many medium capacity commercial-industrial burners. Grade No. 4 is an intermediate fuel that is considered either a light residual or a heavy distillate. Intended for burners that atomize oils of higher viscosity than domestic burners can handle, its permissible viscosity range allows it to be pumped and atomized at relatively low storage temperatures. Grade No. 5 (Light) is a residual fuel of intermediate viscosity for burners that handle fuel more viscous than No. 4 without preheating. Preheating may be necessary in some equipment for burning and, in colder climates, for handling. Grade No. 5 (Heavy) is a residual fuel more viscous than No. 5 (Light), but intended for similar purposes. Preheating is usually necessary for burning and, in colder climates, for handling. Grade No. 6, sometimes referred to as Bunker C, is a high viscosity oil used mostly in commercial and industrial heating. It requires preheating in the storage tank to permit pumping, and additional preheating at the burner to permit atomizing.

Figure 18.1 Approximate Viscosity of Fuel Oils [2013F, Ch 28, Fig 2] 254

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Types and Properties of Liquid Fuels for Engines The primary stationary engine fuels are diesel and gas turbine oils, natural gases, and liquefied petroleum gases. Other fuels include sewage gas, manufactured gas, and gas mixtures. Gasoline and the JP series of gas turbine fuels are rarely used for stationary engines. Properties of the three grades of diesel fuel oils (1-D, 2-D, and 4-D) are listed in ASTM Standard D 975. Grade No. 2-D includes the class of lower volatility distillate gas oils. These fuels are used in high-speed engines with relatively high loads and uniform speeds, or in engines not requiring fuels with the higher volatility or other properties specified for Grade No. 1-D. Grade No. 4-D covers the class of more viscous distillates and blends of these distillates with residual fuel oils. These fuels are used in low- and medium-speed engines involving sustained loads at essentially constant speed. Property specifications and test methods for Grade No. 1-D, 2-D, and 4-D diesel fuel oils are essentially identical to specifications of Grade No. 1, 2, and 4 fuel oils, respectively. However, diesel fuel oils have an additional specification for cetane number, which measures ignition quality and influences combustion roughness. Cetane number requirements depend on engine design, size, speed and load variations, and starting and atmospheric conditions. An increase in cetane number over values actually required does not improve engine performance. Thus, the cetane number should be as low as possible to assure maximum fuel availability. ASTM Standard D 975 provides several methods for estimating cetane number from other fuel oil properties. ASTM Standard D 2880 for gas turbine fuel oils relates gas turbine fuel oil grades to fuel and diesel fuel oil grades.

Type of Fuel Solid fuels Anthracite Semibituminous Bituminous Lignite Coke Liquid fuels No. 1 fuel oil No. 2 fuel oil No. 5 fuel oil No. 6 fuel oil Gaseous fuels Natural gas Butane Propane


Table 18.3 Approximate Air Requirements for Stoichiometric Combustion of Various Fuels [2013F, Ch 28, Tbl 10] Theoretical Air Required for Combustion lb/lb fuel 9.6 11.2 10.3 6.2 11.2 lb/gal fuel 103 106 112 114 ft3/ft3 fuel 9.6 31.1 24.0

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Table 18.4 Approximate Maximum Theoretical (Stoichiometric) CO2 Values and CO2 Values of Various Fuels with Different Percentages of Excess Air [2013F, Ch 28, Tbl 11]

Theoretical or Maximum CO2, %

Type of Fuel Gaseous Fuels Natural gas Propane gas (commercial) Butane gas (commercial) Mixed gas (natural and carbureted water gas) Carbureted water gas Coke oven gas Liquid Fuels No. 1 and 2 fuel oil No. 6 fuel oil Solid Fuels Bituminous coal Anthracite Coke

Percent CO2 at Given Excess Air Values 20% 40% 60%

12.1 13.9 14.1 11.2 17.2 11.2

9.9 11.4 11.6 12.5 14.2 9.2

8.4 9.6 9.8 10.5 12.1 7.8

7.3 8.4 8.5 9.1 10.6 6.8

15.0 16.5

12.3 13.6

10.5 11.6

9.1 10.1

18.2 20.2 21.0

15.1 16.8 17.5

12.9 14.4 15.0

11.3 12.6 13.0


Table 18.5 Recommended Nominal Size for Fuel Oil Suction Lines from Tank to Pump (Distillate Grades No. 1 and No. 2) [2013F, Ch 22, Tbl 28] Pumping Rate, gph 10 40 70 100 130 160 190 220

25 1/2 1/2 1/2 1/2 1/2 3/4 3/4 3/4

Length of Run in Feet at Maximum Suction Lift of 10 ft 50 75 100 125 150 175 200 250 1/2 1/2 1/2 1/2 1/2 1/2 3/4 3/4 1/2 1/2 1/2 1/2 3/4 3/4 3/4 3/4 1/2 3/4 3/4 3/4 3/4 3/4 1 1 3/4 3/4 3/4 3/4 1 1 1 1 3/4 3/4 1 1 1 1 1 1 1/4 3/4 3/4 1 1 1 1 1 1/4 1 1/4 3/4 1 1 1 1 1 1/4 1 1/4 1 1/4 1 1 1 1 1 1/4 1 1/4 1 1/4 1 1/4

300 1 1 1 1 1/4 1 1/4 1 1/4 2 2

Table 18.6 Recommended Nominal Size for Fuel Oil Suction Lines from Tank to Pump (Residual Grades No. 5 and No. 6) [2013F, Ch 22, Tbl 27] Pumping Rate, gph 10 40 70 100 130 160 190 220 Notes:

25 1 1/2 1 1/2 1 1/2 2 2 2 2 2 1/2

Length of Run in Feet at Maximum Suction Lift of 15 ft 50 75 100 125 150 175 200 250 1 1/2 1 1/2 1 1/2 1 1/2 1 1/2 2 2 2 1/2 1 1/2 1 1/2 2 2 2 1/2 2 1/2 2 1/2 2 1/2 2 2 2 2 2 1/2 2 1/2 2 1/2 3 2 2 2 1/2 2 1/2 3 3 3 3 2 2 1/2 2 1/2 2 1/2 3 3 3 3 2 2 1/2 2 1/2 2 1/2 3 3 3 4 2 1/2 2 1/2 2 1/2 3 3 3 4 4 2 1/2 2 1/2 3 3 3 4 4 4

300 2 1/2 3 3 3 4 4 4 4

1. Pipe sizes smaller than 1 in. IPS are not recommended for use with residual grade fuel oils. 2. Lines conveying fuel oil from pump discharge port to burners and tank return may be reduced by one or two sizes, depending on piping length and pressure losses.

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19.

OWNING AND OPERATING

Maintenance Costs

Estimating Maintenance Costs Total HVAC maintenance cost for new and existing buildings with various types of equipment may be estimated several ways, using several resources. Equipment maintenance requirements can be obtained from the equipment manufacturers for large or custom pieces of equipment. Estimating in-house labor requirements can be difficult; BOMA provides guidance on this topic. Many independent mechanical service companies provide preventative maintenance contracts. These firms typically have proprietary estimating programs developed through their experience, and often provide generalized maintenance costs to engineers and owners upon request, without obligation. Table 19.1

Owning and Operating

The maintenance cost of mechanical systems varies widely depending upon configuration, equipment locations, accessibility, system complexity, service duty, geography, and system reliability requirements. Dohrmann and Alereza (1986) obtained maintenance costs and HVAC system information from 342 buildings located in 35 states in the United States. In 1983 U.S. dollars, data collected showed a mean HVAC system maintenance cost of $0.32/ft2 per year, with a median cost of $0.24/ ft2 per year. Building age has a statistically significant but minor effect on HVAC maintenance costs. Analysis also indicated that building size is not statistically significant in explaining cost variation. The type of maintenance program or service agency that building management chooses can also have a significant effect on total HVAC maintenance costs. Although extensive or thorough routine and preventive maintenance programs cost more to administer, they usually extend equipment life; improve reliability; and reduce system downtime, energy costs, and overall lifecycle costs. Some maintenance cost data are available, both in the public domain and from proprietary sources used by various commercial service providers. These sources may include equipment manufacturers, independent service providers, insurers, government agencies (e.g., the U.S. General Services Administration), and industry-related organizations [e.g., the Building Owners and Managers Association (BOMA)] and service industry publications. More traditional, widely used products and components are likely to have statistically reliable records. However, design changes or modifications necessitated by industry changes, such as alternative refrigerants, may make historical data less relevant. Newer HVAC products, components, system configurations, control systems and protocols, and upgraded or revised system applications present an additional challenge. Care is required when using data not drawn from broad experience or field reports. In many cases, maintenance information is proprietary or was sponsored by a particular entity or group. Particular care should be taken when using such data. It is the user’s responsibility to obtain these data and to determine their appropriateness and suitability for the application being considered. ASHRAE research project TRP-1237 (Abramson et al. 2005) developed a standardized Internet-based data collection tool and database on HVAC equipment service life and maintenance costs. The database was seeded with data on 163 buildings from around the country. Maintenance cost data were gathered for total HVAC system maintenance costs from 100 facilities. In 2004 dollars, the mean HVAC maintenance cost from these data was $0.47/ft2, and the median cost was $0.44/ft2. Table 19.1 compares these figures with estimates reported by Dohrmann and Alereza (1986), both in terms of contemporary dollars, and in 2004 dollars, and shows that the cost per square foot varies widely between studies.

Comparison of Maintenance Costs Between Studies [2011A, Ch 37, Tbl 6]

Survey Dohrmann and Alereza (1986) Abramson et al. (2005)

Cost per ft2, as Reported Mean Median $0.32 $0.24 $0.47 $0.44

Consumer Price Index 99.6 188.9

Cost per ft2, 2004 Dollars Mean Median $0.61 $0.46 $0.47 $0.44 257

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When evaluating various HVAC systems during design or retrofit, the absolute magnitude of maintenance costs may not be as important as the relative costs. Whichever estimating method or resource is selected, it should be used consistently throughout any evaluation. Mixing information from different resources in an evaluation may provide erroneous results. Applying simple costs per unit of building floor area for maintenance is highly discouraged. Maintenance costs can be generalized by system types. When projecting maintenance costs for different HVAC systems, the major system components need to be identified with a required level of maintenance. The potential long-term costs of environmental issues on maintenance costs should also be considered.

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Table 19.2

Owning and Operating Cost Data and Summary [2011A, Ch 37, Tbl 1]

OWNING COSTS I.

Initial Cost of System

II.

Periodic Costs

_______

A. Income taxes

_______

B. Property taxes

_______

C. Insurance

_______

D. Rent

_______

E.

_______

Other periodic costs

_______

Total Periodic Costs III.

Replacement Cost

_______

IV.

Salvage Value

_______ _______

Total Owning Costs OPERATING COSTS V.

Annual Utility, Fuel, Water, etc., Costs A. Utilities 1. Electricity

_______

2. Natural gas

_______

3. Water/sewer

_______

4. Purchased steam

_______

5. Purchased hot/chilled water

_______

B. Fuels 1. Propane

_______

2. Fuel oil

_______ _______

4. Coal

_______

C. On-site generation of electricity

_______

D. Other utility, fuel, water, etc., costs

_______

Total


3. Diesel

_______

VI. Annual Maintenance Allowances/Costs A. In-house labor

_______

B. Contracted maintenance service

_______

C. In-house materials D.

Other maintenance allowances/costs (e.g., water treatment)

Total

_______ _______ _______

VII. Annual Administration Costs Total Annual Operating Costs TOTAL ANNUAL OWNING AND OPERATING COSTS

_______ _______ _______

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Simple Payback This ignores inflation and the time value of money. The annual revenue stream cost savings and other factors are estimated and divided into the initial capital outlay; the result is the simple payback time in years.

Life Cycle Costs A representation in present dollars of the cost of an investment over its lifetime is useful for evaluating mutually exclusive alternatives that have the same anticipated lifetime. A discount rate is required for a life-cycle-cost calculation. The discount rate represents the cost of capital to building owners. In essence, it is the rate on a loan (or bond) adjusted to account for inflation and taxes. A 3% real discount rate is typical for energy policy analyses. Higher rates are often used by private investors for economic evaluation of commercial construction. To account for inflation and fuel escalation, either lower the discount rate or inflate future energy and maintenance costs. Life-cycle cost is calculated by determining the present worth of the cost of an investment. For system alternatives, it is LCC = IC + ESPWF(COSTenergy + COSTmaint) where LCC = life-cycle cost IC = initial cost premium of alternative ESPWF = equal series present worth factor (see Table 19.3) COSTenergy = yearly energy cost saving COSTmaint = yearly maintenance cost reduction ESPWF for other lifetimes and discount rates can be calculated from 1 + d  n – 1ESPWF = ---------------------------d  1 + d n where n = lifetime in years and d = discount rate in percent/100. Note that ESPWF can only be used when annual costs remain constant.

Capital Recovery Factors


The future equal payments to repay a present value of money is determined by the capital recovery factor, which is the reciprocal of the present worth factor for a series of equal payments. i  1 + i  n - = -------------------------i CRF = -------------------------1 + in – 1 1 –  1 + i n

Improved Payback Analysis Similar to simple payback but cost of money is considered  CRF   i – CRF  n = ln -------------------------------------------------ln  1 + i 

260

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Table 19.3 Lifetime (years) 7 10 15

2.5% 6.35 8.75 12.38

3.0% 6.23 8.53 11.94

Present Worth Factors

3.5% 6.11 8.32 11.52

Discount Rate 4.0% 4.5% 6.00 5.89 8.11 7.91 11.12 10.74

7% 5.39 7.02 9.11

10% 4.8 6.14 7.61

15% 4.16 5.02 5.85

Table 19.4 Annual Capital Recovery Factors [2003A, Ch 36, Tbl 5] Rate of Return or Interest Rate, % per Year Years 3.5

4.5

6

8

10

2

0.52640

0.53400

0.54544

0.56077

0.57619

4

0.27225

0.27874

0.28859

0.30192

0.31547

6

0.18767

0.19388

0.20336

0.21632

0.22961

8

0.14548

0.15161

0.16104

0.17401

0.18744

10

0.12024

0.12638

0.13587

0.14903

0.16275

12

0.10348

0.10967

0.11928

0.13270

0.14676

14

0.09157

0.09782

0.10758

0.12130

0.13575

16

0.08268

0.08902

0.09895

0.11298

0.12782

18

0.07582

0.08224

0.09236

0.10670

0.12193


Figure 19.1 Capital Recovery Factor Versus Time [2003A, Ch 36, Fig 1]

261

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20.

SOUND

Sound Pressure and Sound Pressure Level Sound intensity is difficult to measure directly, but sound pressure is relatively easy to measure; the human ear and microphones are pressure-sensitive devices. A decibel scale for sound pressure can be created in a manner analogous to the decibel scale for sound intensity, with a reference pressure of 20 Pa, which corresponds to the approximate threshold of hearing. Since pressure squared is proportional to intensity, sound pressure level is Lp = 10 log(p/pref )2 re pref Since p/pref is 20 Pa, which is 2  105 Pa, and since 10 logp2 = 20 logp, Lp = 20 log(p/2  10–5) re 20 Pa where p is the root mean square (rms) value of pressure in micropascals. Or Lp = 20 log p + 94 db re 20 Pa The human ear responds across a broad range of sound pressures. The linear range scale for sound pressure in Table 20.1 is awkward in this form; therefore, the equivalent logarithmic notations should be used. Table 20.1

Typical Sound Pressures and Sound Pressure Levels [2013F, Ch 8, Tbl 1]

Source

Sound

Military jet takeoff at 100 ft

Sound Pressure, Pa 200

Sound Pressure Level, dB re 20 μPa 140

Subjective Reaction Extreme danger

Artillery fire at 10 ft

63.2

130

Passenger jet takeoff at 50 ft

20

120

Threshold of pain Threshold of discomfort

Loud rock band

6.3

110

Automobile horn at 10 ft

2

100

Unmuffled large diesel engine at 130 ft

0.6

90

Accelerating diesel truck at 50 ft

0.2

80

Freight train at 100 ft

0.06

70

Conversational speech at 3 ft

0.02

60

Window air conditioner at 3 ft

0.006

50

Quiet residential area

0.002

40

Very loud

Moderate

Whispered conversation at 6 ft

0.0006

30

Buzzing insect at 3 ft

0.0002

20

Threshold of good hearing

0.00006

10

Faint

Threshold of excellent youthful hearing

0.00002

0

Threshold of hearing

262

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Combining Sound Levels To estimate the levels from multiple sources from the levels from each source, the intensities (not the levels) must be added. Thus, the levels must first be converted to find intensities, the intensities summed, and then converted to a level again, so the combination of multiple levels L1, L2, etc., produces a level Lsum given by L sum = 10 log

L  10

 10 i i 2

L  10

2

where for sound pressure level (Lp), 10 i is p i  p ref , and Li is the sound pressure level for the ith source. A simpler and slightly less accurate method is outlined in Table 20.2. This method, although not exact, results in errors of 1 dB or less. The process with a series of levels may be shortened by combining the largest with the next largest, then combining this sum with the third largest, then the fourth largest, and so on until the combination of the remaining levels is 10 dB lower than the combined level. The process may then be stopped.

Sound Power and Sound Power Level A fundamental characteristic of an acoustic source is its ability to radiate energy. Some energy input excites the source, which radiates some fraction of this energy in the form of sound. Since unit power radiated through a unit sphere yields unit intensity, the power reference base, established by international agreement, is 1 picowatt (pW) (1012 W). The reference quantity used should be stated explicitly. A definition of sound power level is, therefore Lw = logw/(10–12W) dB re 1 pW

or

Lw = 10 logw + 120 dB re 1 pW

Table 20.2 Combining Two Sound Levels [2013F, Ch 8, Tbl 3] Difference between levels to be combined, dB

0 to 1

2 to 4

5 to 9

10 and More

Number of decibels to add to highest level to obtain combined level

3

2

1

0

Sound

Figure 20.1

Curves Showing A- and C-Weighting Responses for Sound Level Meters [2013F, Ch 8, Fig 1] 263

further reprodu


Table 20.3 Mid-Band and Approximate Upper and Lower Cutoff Frequencies for Octave and 1/3 Octave Band Filters [2013F, Ch 8, Tbl 4] Octave Bands, Hz Midband

Upper

11.2

16

22.4

22.4

31.5

45

45

63

90

90

125

180

180

250

355

355

500

710

710

1,000

1,400

1,400

2,000

2,800

2,800

4,000

5,600

5,600

8,000

11,200

11,200

16,000

22,400

Lower 11.2 14 18 22.4 28 35.5 45 56 71 90 112 140 180 224 280 355 450 560 710 900 1,120 1,400 1,800 2,240 2,800 3,550 4,500 5,600 7,100 9,000 11,200 14,000 18,000

1/3 Octave Bands, Hz Midband 12.5 16 20 25 31.5 40 50 63 80 100 125 160 200 250 315 400 500 630 800 1,000 1,250 1,600 2,000 2,500 3,150 4,000 5,000 6,300 8,000 10,000 12,500 16,000 20,000

Upper 14 18 22.4 28 35.5 45 56 71 90 112 140 180 224 280 355 450 560 710 900 1,120 1,400 1,800 2,240 2,800 3,550 4,500 5,600 7,100 9,000 11,200 14,000 18,000 22,400

Sound

Lower

264

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Table 20.4 Design Guidelines for HVAC-Related Background Sound in Rooms [2011A, Ch 48, Tbl 1] Approximate Octave Overall Sound Band Pressure Analysisa Levela NC/RCb

dBAc

Rooms with Intrusion from Outdoor Noise Sourcesd

Traffic noise

N/A

45

70

Aircraft flyovers

N/A

45

70

Residences, Apartments, Condominiums

Living areas

30

35

60

Bathrooms, kitchens, utility rooms

35

40

60

Hotels/Motels

Individual rooms or suites

30

35

60

Room Types

Office Buildings

Courtrooms Performing Arts Spaces

Hospitals and Clinics

Laboratories

dBCc

Meeting/banquet rooms

30

35

60

Corridors and lobbies

40

45

65

Service/support areas

40

45

65

Executive and private offices

30

35

60

Conference rooms

30

35

60

Teleconference rooms

25

30

55

Open-plan offices

40

45

65


40

45

65

Unamplified speech

30

35

60

Amplified speech

35

40

60

Drama theaters, concert and recital halls

20

25

50

Music teaching studios

25

30

55

Music practice rooms

30

35

60

Patient rooms

30

35

60

Wards

35

40

60

Operating and procedure rooms

35

40

60


40

45

65

Testing/research w/minimal speech communication

50

55

75

Extensive phone use and speech communication

45

50

70

Group teaching

35

40

60

Churches, Mosques, Synagogues General assembly with critical music programse

25

30

55

Schoolsf

Classrooms

30

35

60

Large lecture rooms with speech amplification

30

35

60

Large lecture rooms without speech amplification

25

30

55

Libraries Indoor Stadiums, Gymnasiums

30

35

60

Gymnasiums and natatoriumsg

45

50

70

Large-seating-capacity spaces with speech amplificationg

50

55

75

N/A = Not applicable ranges are based on judgment and experience, and represent general limits of acceptability for typical building occupancies. bNC: this metric plots octave band sound levels against a family of reference curves, with the number rating equal to the highest tangent line value. RC: when sound quality in the space is important, the RC metric provides a diagnostic tool to quantify both the speech interference level and spectral imbalance. cdBA and dBC: these are overall sound pressure level measurements with A- and C-weighting, and serve as good references for a fast, single-number measurement. They are also appropriate for specification in cases where no octave band sound data are available for design. dIntrusive noise is addressed here for use in evaluating possible non-HVAC noise that is likely to contribute to background noise levels. eAn experienced acoustical consultant should be retained for guidance on acoustically critical spaces (below RC 30) and for all performing arts spaces. fSome educators and others believe that HVAC-related sound criteria for schools, as listed in previous editions of this table, are too high and impede learning for affected groups of all ages. See ANSI/ASA Standard S12.60 (ASA 2009, 2010) for classroom acoustics and a justification for lower sound criteria in schools. The HVAC component of total noise meets the background noise requirement of that standard if HVAC-related background sound is approximately NC/RC 25. Within this category, designs for K-8 schools should be quieter than those for high schools and colleges. gRC or NC criteria for these spaces need only be selected for the desired speech and hearing conditions. aValues and

Sound

265

further reprodu


Table 20.5

Method

NC

RC Mark II

Can rate components Limited quality assessment Does not evaluate low-frequency rumble Used to evaluate systems Should not be used to evaluate components Evaluates sound quality Provides improved diagnostics capability Can rate components Some quality assessment Some quality assessment Attempts to quantify fluctuations

Considers Speech Interference Effects Yes

Components Evaluates Presently Sound Rated by Each Quality Method Cooling towers Water chillers No Condensing units

Yes

Somewhat

Air terminals Diffusers

Yes

Yes

Not used for component rating

Yes

Somewhat

See NC

Somewhat

Not used for component rating

Yes

Sound

RNC

Overview

No quality assessment Frequently used for outdoor noise ordinances

dBA

NCB

Comparison of Sound Rating Methods [2011A, Ch 48, Tbl 4]

Figure 20.2

NC (Noise Criteria) Curves and Typical Spectrum (Curve with Symbols) [2013F, Ch 8, Fig 7]

266

further reprodu


Figure 20.3 Room Criteria Curves, Mark II [2011A, Ch 48, Fig 6]

Sound

Figure 20.4

Typical Paths of Noise and Vibration Propagation in HVAC Systems [2011A, Ch 48, Fig 1] 267

further reprodu


Figure 20.5 Comparison of 5 ft Dissipative and Reactive Silencer Performance— Film Liner to Conform to NFPA 90A [2011A, Ch 48, Fig 23]

Notes: 1. Slopes of 1 in 7 preferred. Slopes of 1 in 4 permitted below 2000 fpm. 2. Dimension A should be at least 1.5 times B, where B is largest discharge duct dimension. 3. Rugged turning vanes should extend full radius of elbow. 4. Minimum 6 in. radius required.

Sound

Figure 20.6 Various Outlet Configurations for Centrifugal Fans and Their Possible Rumble Conditions [2011A, Ch 48, Fig 25]

268

further reprodu


A number of AHRI, AMCA, CTI, and ANSI sound standards are used by equipment manufacturers to provide accurate sound data. Manufacturer-supplied data in accordance with the appropriate standard should be used in preference to any earlier empirical information in evaluating the noise resulting from a particular equipment item.

Figure 20.7

Frequencies at Which Different Types of Mechanical Equipment Generally Control Sound Spectra [2011A, Ch 48, Fig 4]

Table 20.6 Sound Transmission Class (STC) and Transmission Loss Values of Typical Mechanical Equipment Room Wall, Floor, and Ceiling Types, dB [2011A, Ch 48, Tbl 40]

Room Construction Type 8 in. CMU* 8 in. CMU with 5/8 in. GWB* on furring strips 5/8 in. GWB on both sides of 3 5/8 in. metal studs 5/8 in. GWB on both sides of 3 5/8 in. metal studs with fiberglass insulation in cavity 2 layers of 5/8 in. GWB on both sides of 3 5/8 in. metal studs with fiberglass insulation in cavity Double row of 3 5/8 in. metal studs, 1 in. apart, each with 2 layers of 5/8 in. GWB and fiberglass insulation in cavity 6 in. solid concrete floor/ceiling

63

50

35

35

41

44

50

57

64

53

33

32

44

50

56

59

65

38

18

16

33

47

55

43

47

49

16

23

44

58

64

52

53

56

19

32

50

62

67

58

63

64

23

40

54

62

71

69

74

53

40

40

40

49

58

67

76

72

44

52

58

73

87

97

100

84

53

63

70

84

93

104

105

Sound

6 in. solid concrete floor with 4 in. isolated concrete slab and fiberglass insulation in cavity 6 in. solid concrete floor with two layers of 5/8 in. GWB hung on spring isolators with fiberglass insulation in cavity

Octave Midband Frequency, Hz 125 250 500 1000 2000 4000

STC

Note: Actual material composition (e.g., density, porosity, stiffness) affects transmission loss and STC values. *CMU = concrete masonry unit; GWB = gypsum wallboard. 269

further reprodu


Table 20.7 Sound Sources, Transmission Paths, and Recommended Noise Reduction Methods [2011A, Ch 48, Tbl 6] Sound Source Path No. Circulating fans; grilles; registers; diffusers; unitary equipment in room 1 Induction coil and fan-powered VAV mixing units 1, 2 Unitary equipment located outside of room served; remotely located air-handling 2, 3 equipment, such as fans, blowers, dampers, duct fittings, and air washers Compressors, pumps, and other reciprocating and rotating equipment (excluding 4, 5, 6 air-handling equipment) Cooling towers; air-cooled condensers 4, 5, 6, 7 Exhaust fans; window air conditioners 7, 8 Sound transmission between rooms 9, 10 No. Transmission Paths Noise Reduction Methods 1 Direct sound radiated from sound source Direct sound can be controlled only by to ear selecting quiet equipment. Reflected sound from walls, ceiling, Reflected sound is controlled by adding and floor sound absorption to the room and to equipment location.

Sound

2

Air- and structureborne sound radiated from Design duct and fittings for low turbulence; casings and through walls of ducts and locate high-velocity ducts in noncritical plenums is transmitted through walls and areas; isolate ducts and sound plenums ceiling into room from structure with neoprene or spring hangers. 3 Airborne sound radiated through supply and Select fans for minimum sound power; use return air ducts to diffusers in room and ducts lined with sound-absorbing material; then to listener by Path 1 use duct silencers or sound plenums in supply and return air ducts. 4 Noise transmitted through equipment room Locate equipment rooms away from critical walls and floors to adjacent rooms areas; use masonry blocks or concrete for equipment room walls and floor. 5 Vibration transmitted via building structure to Mount all machines on properly designed adjacent walls and ceilings, from which it vibration isolators; design mechanical radiates as noise into room by Path 1 equipment room for dynamic loads; balance rotating and reciprocating equipment. 6 Vibration transmission along pipes and duct Isolate pipe and ducts from structure with walls neoprene or spring hangers; install flexible connectors between pipes, ducts, and vibrating machines. 7 Noise radiated to outside enters room Locate equipment away from critical areas; windows use barriers and covers to interrupt noise paths; select quiet equipment. 8 Inside noise follows Path 1 Select quiet equipment. 9 Noise transmitted to an air diffuser in a room, Design and install duct attenuation to match into a duct, and out through an air diffuser transmission loss of wall between rooms. in another room 10 Sound transmission through, over, and around Extend partition to ceiling slab and tightly room partition seal all around; seal all pipe, conduit, duct, and other partition penetrations.

270

further reprodu


21.

VIBRATION Natural frequency,

where k is the stiffness of vibration isolator (force per unit deflection) and M is the mass of equipment supported by the isolator.

Vibration

1 k f n = ------ ---2 M

3.13- Hz f n = --------- st where stis the static deflection of the isolator in inches. Transmissibility is the ratio of the amplitudes of the force transmitted to the building structure to the exciting force produced by the vibrating equipment. Transmissibility is inversely proportional to the square of the disturbing frequency, fd, to the natural frequency, fn. 1 T = ----------------------------1 –  fd  fn  2 at fd = fn, resonance occurs. Vibration isolation is effective only at a fd/fn ratio > 3.5. When supporting structure stiffness is not large with respect to stiffness of isolator, it becomes a two-degree of freedom system. In this case, choose an isolator that will provide static deflection eight to ten times that of the estimated floor static deflection due to the added weight of the equipment. Seismic snubbers must be included in or with isolators to limit equipment movement.

Figure 21.1 Single-Degree-of-Freedom System [2013F, Ch 8, Fig 8]

Figure 21.2 Two-Degree-of-Freedom System [2013F, Ch 8, Fig 11] 271

further reprodu

All All All All

All

All

All

All

All

Screw

Absorption

Air-cooled recip., scroll

Air-cooled screw

All All All All All

15

All

All

All

Tank-mounted vert.

Base-mounted

Large reciprocating

Tank-mounted horiz.

10

Air Compressors and Vacuum Pumps

All All

All

Centrifugal, scroll

RPM

Reciprocating

Refrigeration Machines and Chillers

Equipment Type

Horsepower and Other

C

C

C

C

A

A

A

A

A

A

A

3

3

3

3

3

4

1

1

1

1

2

Base Isolator Type Type

0.75

0.75

0.75

0.75

0.75

1.00

0.25

0.25

1.00

0.25

0.25

Min. Defl., in.

Slab on Grade

C

C

C

C

A

A

A

A

A

A

A

3

3

3

3

3

4

4

4

4

4

4


0.75

0.75

0.75

0.75

0.75

1.50

1.50

0.75

1.5

0.75

0.75

Min. Defl., in.

Up to 20 ft

C

C

C

C

A

B

A

A

A

A

A

3

3

3

3

3

4

4

4

4

4

4


20 to 30 ft

1.50

1.50

1.50

1.50

1.50

2.50

1.50

1.50

2.50

1.50

1.50

Min. Defl., in.

Floor Span

Equipment Location (Note 1)

Table 21.1 Selection Guide for Vibration Isolation [2011A, Ch 48, Tbl 47]


C

C

C

C

A

B

A

A

A

A

A

3

3

3

3

3

4

4

4

4

4

4


30 to 40 ft

1.50

1.50

1.50

1.50

1.50

2.50

2.50

1.50

2.50

1.50

2.50

3,14,15

3,14,15

3,15

3,15

3,15

2,4,5,8,12

2,4,5,12

2,3,4,12

2,3,4,8,12

2,3,12

Min. Defl., Reference in. Notes

Vibration


272

further reprodu

All All All

5 to 25

30

40

All All

All

All

Water-tube, copper fin

A

A

A

501 and up

Fire-tube

Boilers

A A

All

Cooling Towers

C A

Up to 300

All

All

C

C

A

A

C

B

1

1

1

1

1

3

3

3

3

3

3

3

2


301 to 500

All

150

All

All

10

50 to 125

All

7.5

RPM

Packaged pump systems

End suction and doublesuction/split case

Inline

Close-coupled

Pumps

Equipment Type


0.12

0.25

6.4

6.4

6.4

0.75

0.75

0.75

0.75

1.50

0.75

0.75

0.25

Min. Defl., in.

Slab on Grade

A

B B

A

A

A

A

C

C

C

A

A

C

C

1

4

4

4

4

3

3

3

3

3

3

3

3


0.12

0.75

19

64

89

0.75

1.50

0.75

0.75

1.50

1.50

0.75

0.75

Min. Defl., in.

Up to 20 ft

A

B

A

A

A

A

C

C

C

A

A

C

C

1

4

4

4

4

3

3

3

3

3

3

3

3


20 to 30 ft

0.12

1.50

19

64

89

1.50

2.50

1.50

1.50

1.50

1.50

1.50

0.75

Min. Defl., in.

Floor Span


30 to 40 ft

B

B

A

A

A

C

C

C

C

A

A

C

C

4

4

4

4

4

3

3

3

3

3

3

3

3


Table 21.1 Selection Guide for Vibration Isolation [2011A, Ch 48, Tbl 47] (Continued)

0.25

2.50

38

64

89

2.50

3.50

2.50

1.50

2.50

1.50

1.50

0.75

4

5,18

5,18

5,8,18

10,16

10,16

16

16

16


Vibration



273

further reprodu

RPM


All

B

3

3

B

301 to 500 501 and up

2

3

3

3

3

3

3

B

2 3

B

All Up to 300

All

40

C

501 and up

C

Up to 300 C

B

501 and up

301 to 500

B

B

A

301 to 500

Up to 300

24 in. diameter and up

2.1 in. SP

2 in. SP

All

Up to 22 in. diameter

Centrifugal Fans

24 in. diameter and up

Up to 22 in. diameter

0.25

0.75

1.50

2.50

0.25

0.75

1.50

2.50

0.75

0.75

2.50

B

B

B

B

C

C

C

B

B

C

A

3

3

3

3

3

3

3

3

3

3

3

0.75

1.50

3.50

0.75

1.50

1.50

3.50

1.50

1.50

3.50

0.75

Min. Defl., in.

Up to 20 ft Base Isolator Type Type

Axial Fans, Plenum Fans, Cabinet Fans, Fan Sections, Centrifugal Inline Fans

Equipment Type


Min. Defl., in.

Slab on Grade

B

B

B

B

C

C

C

B

C

C

A

3

3

3

3

3

3

3

3

3

3

3


20 to 30 ft

0.75

2.50

3.50

0.75

1.50

2.50

3.50

1.50

2.50

3.50

0.75

Min. Defl., in.

Floor Span


C

B

B

B

B

C

C

C

B

C

C

3

3

3

3

3

3

3

3

3

3

3

1.50

2.50

3.50

1.50

2.50

2.50

3.50

1.50

2.50

3.50

0.75

8,19

8,19

8,19

9,19

3,8,9

3,8,9

3,8,9

9,8

9,8

9,8

4,9,8


Vibration

30 to 40 ft Base Isolator Type Type




274

further reprodu

All

All

Condensing Units

All

3

A A A

301 to 500 501 and up

15, 4 in. SP 3

3

A

All

3

1

3

1

1

3

Up to 300

A

A

A

3 3

10

Packaged AH, AC, H, and V Units

All

All

Heat Pumps, Fan-Coils, Computer Room Units

All

All

All

Roof-mounted

A

C

501 and up

All

C C

301 to 500

RPM


Up to 300

50

Wall-mounted

Propeller Fans

Equipment Type


0.75

0.75

0.75

0.75

0.25

0.75

0.25

0.25

1.00

1.50

2.50

Min. Defl., in.

Slab on Grade

A

A

A

A

A

A

A

A

C

C

C

3

3

3

3

4

3

1

1

3

3

3


1.50

2.50

3.50

0.75

0.75

0.75

0.25

0.25

1.50

1.50

3.50

Min. Defl., in.

Up to 20 ft

A

A

A

A

A

A

B

A

C

C

C

3

3

3

3

4

3

4

1

3

3

3


20 to 30 ft

1.50

2.50

3.50

0.75

1.50

0.75

1.50

0.25

1.50

2.50

3.50

Min. Defl., in.

Floor Span


30 to 40 ft

A

A

C

A

A/D

A/D

D

A

C

C

C

3

3

3

3

4

3

4

1

3

3

3



1.50

2.50

3.50

0.75

1.50

1.50

1.50

0.25

2.50

2.50

3.50

4,19

4,19

2,4,8,19

19

2,3,8,9,19

2,3,8,9,19

2,3,8,9,19


Vibration



275

further reprodu

RPM

A

3

3

3

3

1

3

3

0.75

0.75

0.75

0.50

0.25

0.75

0.75

C

A

A

D

C

C

C

3

3

3

3

3

3

3


1.50

0.75

0.50

0.75

1.50

1.50

3.50

Min. Defl., in.

Up to 20 ft

C

A

A

C

C

C

3

3

3

3

3

3


20 to 30 ft

Base Types: A. No base, isolators attached directly to equipment (Note 28) B. Structural steel rails or base (Notes 29 and 30) C. Concrete inertia base (Note 30) D. Curb-mounted base (Note 31)

C

C

C

3

3

3


30 to 40 ft

2.50

2.50

3.50

Isolator Types: 1. Pad, rubber, or glass fiber (Notes 20 and 21) 2. Rubber floor isolator or hanger (Notes 20 and 25) 3. Spring floor isolator or hanger (Notes 22, 23, and 26) 4. Restrained spring isolator (Notes 22 and 24) 5. Thrust restraint (Note 27) 6. Air spring (Note 25)

2.50

0.75

0.50

C

A

A

3

3

3

3.50

0.75

0.50

2,3,4

7

7

5,6,8,17

2,3,4,9

2,3,4,9

2,3,4,8,9


Vibration

See Reference Note 17

1.50

2.50

3.50

Min. Defl., in.

Floor Span

Piping and Ducts (See sections on Isolating Vibration and Noise in Piping Systems and Isolating Duct Vibration for isolator selection.)

A

A

A/D

601 cfm All

All

B

501 and up

B B

301 to 500

Up to 300


600 cfm

Engine-Driven Generators All

Small fans, fan-powered boxes

All

15, 4 in. SP

Ducted Rotating Equipment

Packaged Rooftop Equipment

Equipment Type


Min. Defl., in.

Slab on Grade





276

further reprodu

Vibration

Note 1. Isolator deflections shown are based on a reasonably expected floor stiffness according to floor span and class of equipment. Certain spaces may dictate higher levels of isolation. For example, bar joist roofs may require a static deflection of 1.5 in. over factories, but 2.5 in. over commercial office buildings. Note 2. For large equipment capable of generating substantial vibratory forces and structureborne noise, increase isolator deflection, if necessary, so isolator stiffness is less than one-tenth the stiffness of the supporting structure, as defined by the deflection due to load at the equipment support. Note 3. For noisy equipment adjoining or near noise-sensitive areas, see the section on Mechanical Equipment Room Sound Isolation. Note 4. Certain designs cannot be installed directly on individual isolators (type A), and the equipment manufacturer or a vibration specialist should be consulted on the need for supplemental support (base type). Note 5. Wind load conditions must be considered. Restraint can be achieved with restrained spring isolators (type 4), supplemental bracing, snubbers, or limit stops. Also see Chapter 55. Note 6. Certain types of equipment require a curb-mounted base (type D). Airborne noise must be considered. Note 7. See section on Resilient Pipe Hangers and Supports for hanger locations adjoining equipment and in equipment rooms. Note 8. To avoid isolator resonance problems, select isolator deflection so that resonance frequency is 40% or less of the lowest normal operating speed of equipment (see Chapter 8 in the 2009 ASHRAE Handbook—Fundamentals). Some equipment, such as variable-frequency drives, and high-speed equipment, such as screw chillers and vaneaxial fans, contain very-high-frequency vibration. This equipment creates new technical challenges in the isolation of high-frequency noise and vibration from a building’s structure. Structural resonances both internal and external to the isolators can significantly degrade their performance at high frequencies. Unfortunately, at present no test standard exists for measuring the high-frequency dynamic properties of isolators, and commercially available products are not tested to determine their effectiveness for high frequencies. To reduce the chance of high-frequency vibration transmission, add a 1 in. thick pad (type 1, Note 20) to the base plate of spring isolators (type 3, Note 22, 23, 24). For some sensitive locations, air springs (Note 25) may be required. If equipment is located near extremely noise-sensitive areas, follow the recommendations of an acoustical consultant. Note 9. To limit undesirable movement, thrust restraints (type 5) are required for all ceiling-suspended and floor-mounted units operating at 2 in. of water or more total static pressure. Note 10. Pumps over 75 hp may need extra mass and restraints. Note 11. See text for full discussion.

These notes are keyed to the column titled Reference Notes in Table 47 and to other reference numbers throughout the table. Although the guide is conservative, cases may arise where vibration transmission to the building is still excessive. If the problem persists after all short circuits have been eliminated, it can almost always be corrected by altering the support path (e.g., from ceiling to floor), increasing isolator deflection, using low-frequency air springs, changing operating speed, improving rotating component balancing, or, as a last resort, changing floor frequency by stiffening or adding more mass. Assistance from a qualified vibration consultant can be very useful in resolving these problems.

Notes for Table: Selection Guide for Vibration Isolation



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Vibration

Note 14. Compressors: When using Y, W, and multihead and multicylinder compressors, obtain the magnitude of unbalanced forces from the equipment manufacturer so the need for an inertia base can be evaluated. Note 15. Compressors: Base-mounted compressors through 5 hp and horizontal tank-type air compressors through 10 hp can be installed directly on spring isolators (type 3) with structural bases (type B) if required, and compressors 15 to 100 hp on spring isolators (type 3) with inertia bases (type C) weighing 1 to 2 times the compressor weight. Note 16. Pumps: Concrete inertia bases (type C) are preferred for all flexible-coupled pumps and are desirable for most close-coupled pumps, although steel bases (type B) can be used. Close-coupled pumps should not be installed directly on individual isolators (type A) because the impeller usually overhangs the motor support base, causing the rear mounting to be in tension. The primary requirements for type C bases are strength and shape to accommodate base elbow supports. Mass is not usually a factor, except for pumps over 75 hp, where extra mass helps limit excess movement due to starting torque and forces. Concrete bases (type C) should be designed for a thickness of one-tenth the longest dimension with minimum thickness as follows: (1) for up to 30 hp, 6 in.; (2) for 40 to 75 hp, 8 in.; and (3) for 100 hp and up, 12 in. Pumps over 75 hp and multistage pumps may exhibit excessive motion at start-up (“heaving”); supplemental restraining devices can be installed if necessary. Pumps over 125 hp may generate high starting forces; a vibration specialist should be consulted. Note 17. Packaged Rooftop Air-Conditioning Equipment: This equipment is usually installed on lightweight structures that are susceptible to sound and vibration transmission problems. The noise problems are compounded further by curb-mounted equipment, which requires large roof openings for supply and return air. The table shows type D vibration isolator selections for all spans up to 20 ft, but extreme care must be taken for equipment located on spans of over 20 ft, especially if construction is open web joists or thin, lightweight slabs. The recommended procedure is to determine the additional deflection caused by equipment in the roof. If additional roof deflection is 0.25 in. or less, the isolator should be selected for 10 times the additional roof deflection. If additional roof deflection is over 0.25 in., supplemental roof stiffening should be installed to bring the roof deflection down below 0.25 in., or the unit should be relocated to a stiffer roof position. For mechanical units capable of generating high noise levels, mount the unit on a platform above the roof deck to provide an air gap (buffer zone) and locate the unit away from the associated roof penetration to allow acoustical treatment of ducts before they enter the building. Some rooftop equipment has compressors, fans, and other equipment isolated internally. This isolation is not always reliable because of internal short-circuiting, inadequate static deflection, or panel resonances. It is recommended that rooftop equipment over 300 lb be isolated externally, as if internal isolation was not used. Note 18. Cooling Towers: These are normally isolated with restrained spring isolators (type 4) directly under the tower or tower dunnage. High-deflection isolators proposed for use directly under the motor-fan assembly must be used with extreme caution to ensure stability and safety under all weather conditions. See Note 5.

Isolation for Specific Equipment Note 12. Refrigeration Machines: Large centrifugal, screw, and reciprocating refrigeration machines may generate very high noise levels; special attention is required when such equipment is installed in upper-story locations or near noise-sensitive areas. If equipment is located near extremely noise-sensitive areas, follow the recommendations of an acoustical consultant. Note 13. Compressors: The two basic reciprocating compressors are (1) single- and double-cylinder vertical, horizontal or L-head, which are usually air compressors; and (2) Y, W, and multihead or multicylinder air and refrigeration compressors. Single- and double-cylinder compressors generate high vibratory forces requiring large inertia bases (type C) and are generally not suitable for upper-story locations. If this equipment must be installed in an upper-story location or at-grade location near noise-sensitive areas, the expected maximum unbalanced force data must be obtained from the equipment manufacturer and a vibration specialist consulted for design of the isolation system.



278

further reprodu

Vibration

Note 21. Glass fiber with elastic coating (type 1). This type of isolation pad is precompressed molded fiberglass pads individually coated with a flexible, moisture-impervious elastomeric membrane. Natural frequency of fiberglass vibration isolators should be essentially constant for the operating load range of the supported equipment. Weight load is evenly distributed over the entire pad surface. Metal loading plates can be used for this purpose.

Note 20. Rubber isolators are available in pad (type 1) and molded (type 2) configurations. Pads are used in single or multiple layers. Molded isolators come in a range of 30 to 70 durometer (a measure of stiffness). Material in excess of 70 durometer is usually ineffective as an isolator. Isolators are designed for up to 0.5 in. deflection, but are used where 0.3 in. or less deflection is required. Solid rubber and composite fabric and rubber pads are also available. They provide high load capacities with small deflection and are used as noise barriers under columns and for pipe supports. These pad types work well only when they are properly loaded and the weight load is evenly distributed over the entire pad surface. Metal loading plates can be used for this purpose.

Vibration Isolators: Materials, Types, and Configurations Notes 20 through 31 include figures to assist in evaluating commercially available isolators for HVAC equipment. The isolator selected for a particular application depends on the required deflection, life, cost, and compatibility with associated structures.

Note 19. Fans and Air-Handling Equipment: Consider the following in selecting isolation systems for fans and air-handling equipment: 1. Fans with wheel diameters of 22 in. and less and all fans operating at speeds up to 300 rpm do not generate large vibratory forces. For fans operating under 300 rpm, select isolator deflection so the isolator natural frequency is 40% or less than the fan speed. For example, for a fan operating at 275 rpm, 0.4  275 = 110 rpm. Therefore, an isolator natural frequency of 110 rpm or lower is required. This can be accomplished with a 3 in. deflection isolator (type 3). 2. Flexible duct connectors should be installed at the intake and discharge of all fans and air-handling equipment to reduce vibration transmission to air duct structures. 3. Inertia bases (type C) are recommended for all class 2 and 3 fans and air-handling equipment because extra mass allows the use of stiffer springs, which limit heaving movements. 4. Thrust restraints (type 5) that incorporate the same deflection as isolators should be used for all fan heads, all suspended fans, and all base-mounted and suspended air-handling equipment operating at 2 in. or more total static pressure. Restraint movement adjustment must be made under normal operational static pressures.



279

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Vibration

Note 25. Air springs can be designed for any frequency, but are economical only in applications with natural frequencies of 1.33 Hz or less (6 in. or greater deflection). They do not transmit high-frequency noise and are often used to replace high-deflection springs on problem jobs (e.g., large transformers on upper floor installations). A constant air supply (an air compressor with an air dryer) and leveling valves are typically required.

Note 24. Restrained spring isolators (type 4) have hold-down bolts to limit vertical as well as horizontal movement. They are used with (a) equipment with large variations in mass (e.g., boilers, chillers, cooling towers) to restrict movement and prevent strain on piping when water is removed, and (b) outdoor equipment, such as condensing units and cooling towers, to prevent excessive movement due to wind loads. Spring criteria should be the same as open spring isolators, and restraints should have adequate clearance so that they are activated only when a temporary restraint is needed. Closed mounts, or housed spring isolators consist of two telescoping housings separated by a resilient material. These provide lateral snubbing and some vertical damping of equipment movement, but do not limit the vertical movement. Care should be taken in selection and installation to minimize binding and short-circuiting.

Note 23. Open spring isolators (type 3) consist of top and bottom load plates with adjustment bolts for leveling equipment. Springs should be designed with a horizontal stiffness of at least 80% of the vertical stiffness (kx/ky) to ensure stability. Similarly, the springs should have a minimum ratio of 0.8 for the diameter divided by the deflected spring height.

Note 22. Steel springs are the most popular and versatile isolators for HVAC applications because they are available for almost any deflection and have a virtually unlimited life. Spring isolators may have a rubber acoustical barrier to reduce transmission of high-frequency vibration and noise that can migrate down the steel spring coil. They should be corrosion-protected if installed outdoors or in a corrosive environment. The basic types include the following:



280

further reprodu

Note 29. Structural bases (type B) are used where equipment cannot be supported at individual locations and/or where some means is necessary to maintain alignment of component parts in equipment. These bases can be used with spring or rubber isolators (types 2 and 3) and should have enough rigidity to resist all starting and operating forces without supplemental hold-down devices. Bases are made in rectangular configurations using structural members with a depth equal to one-tenth the longest span between isolators. Typical base depth is between 4 and 12 in., except where structural or alignment considerations dictate otherwise.

Note 28. Direct isolation (type A) is used when equipment is unitary and rigid and does not require additional support. Direct isolation can be used with large chillers, some fans, packaged air-handling units, and air-cooled condensers. If there is any doubt that the equipment can be supported directly on isolators, use structural bases (type B) or inertia bases (type C), or consult the equipment manufacturer.

Vibration

DIRECT ISOLATION (Type A)

Note 27. Thrust restraints (type 5) are similar to spring hangers or isolators and are installed in pairs to resist the thrust caused by air pressure. These are typically sized to limit lateral movement to 0.25 in. or less.

Note 26. Isolation hangers (types 2 and 3) are used for suspended pipe and equipment and have rubber, springs, or a combination of spring and rubber elements. Criteria should be similar to open spring isolators, though lateral stability is less important. Where support rod angular misalignment is a concern, use hangers that have sufficient clearance and/or incorporate rubber bushings to prevent the rod from touching the housing. Swivel or traveler arrangements may be necessary for connections to piping systems subject to large thermal movements. Precompessed spring hangers incorporate some means of precompression or preloading of the isolator spring to minimize movement of the isolated equipment or system. These are typically used on piping systems that can change weight substantially between installation and operation.



281

further reprodu

Vibration

Note 32. Curb isolation systems (type D) are specifically designed for curb-supported rooftop equipment and have spring isolation with a watertight, and sometimes airtight, assembly. Rooftop rails consist of upper and lower frames separated by nonadjustable springs and rest on top of architectural roof curbs. Isolation curbs incorporate the roof curb into their design as well. Both kinds are designed with springs that have static deflections in the 1 to 3 in. range to meet the design criteria described in type 3. Flexible elastomeric seals are typically most effective for weatherproofing between the upper and lower frames. A continuous sponge gasket around the perimeter of the top frame is typically applied to further weatherproof the installation.

Note 31. Concrete bases (type C) are used where the supported equipment requires a rigid support (e.g., flexiblecoupled pumps) or excess heaving motion may occur with spring isolators. They consist of a steel pouring form usually with welded-in reinforcing bars, provision for equipment hold-down, and isolator brackets. Like structural bases, concrete bases should be sized to support piping elbow supports, rectangular or T-shaped, and for rigidity, have a depth equal to one-tenth the longest span between isolators. Base depth is typically between 6 and 12 in. unless additional depth is specifically required for mass, rigidity, or component alignment.

Note 30. Structural rails (type B) are used to support equipment that does not require a unitary base or where the isolators are outside the equipment and the rails act as a cradle. Structural rails can be used with spring or rubber isolators and should be rigid enough to support the equipment without flexing. Usual practice is to use structural members with a depth one-tenth of the longest span between isolators, typically between 4 and 12 in., except where structural considerations dictate otherwise.



282

further reprodu


22.

EVAPORATIVE COOLING

Direct Evaporative Air Coolers Air is drawn through porous wetted pads or a spray, or rigid media; and its sensible heat energy evaporates some water. The heat and mass transfer between the air and water lowers the air dry-bulb temperature and increases the humidity at a constant wet-bulb temperature. The dry-bulb temperature of the nearly saturated air approaches the ambient air’s wet-bulb temperature. The process is adiabatic, so no sensible cooling occurs. The extent to which the leaving air temperature from a direct evaporative cooler approaches the thermodynamic wet-bulb temperature of the entering air or the extent to which complete saturation is approached is expressed as the direct saturation efficiency, defined as

where e t1 t2 t

= = = =

Evaporative Cooling

t1 – t2  e = 100 -------------t 1 – t

direct evaporative cooling or saturation efficiency, % dry-bulb temperature of entering air, °F dry-bulb temperature of leaving air, °F thermodynamic wet-bulb temperature of entering air, °F

An efficient wetted pad can reduce the air dry-bulb temperature by as much as 95% of the wet-bulb depression (ambient dry-bulb temperature less wet-bulb temperature), while an inefficient and poorly designed pad may only reduce this by 50% or less. Direct evaporative cooling, though simple and inexpensive, has the disadvantage that if the ambient wet-bulb temperature is higher than about 70°F, the cooling effect is not sufficient for indoor comfort but still may be sufficient for relief cooling applications. Direct evaporative coolers should not recirculate indoor air. Two-inch pad coolers, usually small capacity, operate at 100 to 250 fpm face velocity. Twelve-inch-deep rigid media larger coolers operate at 400 to 600 fpm face velocity and have higher saturation efficiencies.

Figure 22.1

Rigid Media Direct Evaporative Cooler [2012S, Ch 41, Fig 2] 283

further reprodu


Evaporative Cooling

Indirect Evaporative Air Coolers In indirect evaporative air coolers, outdoor air or exhaust air from the conditioned space passes through one side of a heat exchanger. This secondary airstream is cooled by evaporation by direct wetting of the heat exchanger surface, or passing through evaporative cooling media, atomizing spray, or disk evaporator. The surfaces of the heat exchanger are cooled by the secondary airstream. On the other side of the heat exchanger surface, the primary airstream (conditioned air to be supplied to the space) is sensibly cooled. Although the primary air is cooled by secondary air, no moisture is added to the primary air. Because the enthalpy of the primary air decreases, the leaving dry-bulb temperature of the primary air must always be above the entering wet-bulb temperature of the secondary airstream. Dehumidifying in the primary airstream can occur only when the dew point of the primary airstream is several degrees higher than the wet-bulb temperature of the secondary air-stream. This condition exists only when the secondary airstream is drier than the primary airstream, such as when building exhaust air is used for the secondary air. Indirect evaporative cooling efficiency, or wet-bulb depression efficiency (WBDE), is defined as t1 – t2 WBDE = 100 ---------------t 1 – ts where WBDE t1 t2 ts

= = = =

indirect evaporative cooling efficiency,% dry-bulb temperature of entering primary air, °F dry-bulb temperature of leaving primary air, °F wet-bulb temperature of entering secondary air, °F

In a two-stage indirect/direct evaporative cooler, a first-stage indirect evaporative cooler lowers both the dry- and wet-bulb temperature of the incoming air. After leaving the indirect stage, the supply air passes through a second-stage direct evaporative cooler. This method can lower the supply air dry-bulb temperature by 10°F or more below the secondary air wet-bulb temperature. In areas with a higher wet-bulb design temperature or where the design requires a supply air temperature lower than that attainable using indirect/direct evaporative cooling, a third cooling stage may be required. This stage may be a direct-expansion refrigeration unit or a chilled water coil located either upstream or downstream from the direct evaporative cooling stage, but always downstream from the indirect evaporative stage.

Figure 22.2

Indirect Evaporative Cooler Used as Precooler [2012S, Ch 41, Fig 4]

284

further reprodu

40 to 60

60 to 85

65 to 75

60 to 70

35 to 50

Cooling tower to coil

Crossflow plate

Heat pipec

Heat wheeld

Runaround coil 40 to 60

70 to 80

50 to 60

40 to 50

NA

0.6 to 0.8

0.6 to 0.9

0.7 to 1.0

0.7 to 1.0

NA

0.4 to 0.6

0.4 to 0.65

0.5 to 0.7

0.4 to 0.7

0.4 to 0.7

Varies

0.1 to 0.2

0.2 to 0.4

0.1 to 0.2

Varies

> 0.35

0.2 to 0.3

0.15 to 0.25

0.12 to 0.20

Varies

1.00 to 2.00

1.50 to 2.50

1.50 to 2.50

1.20 to 1.70

0.50 to 1.00

Notes Best for serving multiple AHUs from a single cooling tower. No winter heat recovery. Most cost-effective for lower airflows. Some cross contamination possible. Low winter heat recovery. Most cost-effective for large airflows. Some cross contamination possible. Medium winter heat recovery. Best for high airflows. Some cross contamination. Highest winter heat recovery rates. Best for applications where supply and return air ducts are separated. Lowest summer WBDE.

Evaporative Cooling

Notes: aAll air-to-air heat exchangers have equal mass flow on supply and exhaust sides. b Plate and heat pipe are direct spray on exhaust side. Heat wheel and runaround coil systems use 90% WBDE direct evaporative cooling media on exhaust air side. cAssumes six-row heat pipe, 11 fpi, with 500 fpm face velocity on both sides. dAssumes 500 fpm face velocity. Parasitic loss includes wheel rotational power. e Includes air-side static pressure and pumping penalty. fExcludes cooling tower cost and assumes less than 200 ft piping between components.

WBDE = wet-bulb depression efficiency

WBDE,b %

System Typea

Indirect Evaporative Cooling Systems Comparison

Heat Parasitic Recovery Wet-Side Dry-Side Pump Loss Range,e Equipment Efficiency, Air P, Air P, hp per kW/ton of Cost Range,f % in. of water in. of water 10,000 cfm Cooling $/Supply cfm

Table 22.1



285

further reprodu


Evaporative Cooling


Figure 22.3 Two-Stage Indirect/Direct Evaporative Cooling Process [2012S, Ch 41, Fig 6]

Figure 22.4 Three-Stage Indirect/Direct Evaporative Cooler [2012S, Ch 41, Fig 8]

286

further reprodu


Evaporative Cooling

Figure 22.5 Effective Temperature Chart [2011A, Ch 52, Fig 14]

287

further reprodu


23.

AUTOMATIC CONTROLS

HVAC System Components

Duct Static Pressure Control [2011A, Ch 47, Fig 15]

Automatic Controls

Figure 23.1

Figure 23.2

Direct Expansion—Two-Position Control

Figure 23.3

Duct Static Control of Return Fan

288

further reprodu


Figure 23.4

Automatic Controls

Figure 23.5

Modulating Direct-Expansion Cooling

Airflow Tracking Control [2011A, Ch 47, Fig 17]

Figure 23.6 Cooling Tower [2011A, Ch 47, Fig 13] 289

further reprodu


Automatic Controls

Figure 23.7 Economizer Cycle Control

Figure 23.8 Preheat with Secondary Pump and Two-Way Valve

Figure 23.9

Warm-Up Control

290

further reprodu


Figure 23.10

Cooling and Dehumidifying with Reheat [2011A, Ch 47, Fig 25]

Automatic Controls

Figure 23.11 Night Cooldown Control

Figure 23.12 Sprayed Coil Dehumidifier [2011A, Ch 47, Fig 26] 291

further reprodu


Automatic Controls

Figure 23.13 Preheat with Face and Bypass Dampers [2011A, Ch 47, Fig 5]

Figure 23.14 Chemical Dehumidifier [2011A, Ch 47, Fig 28]

Figure 23.15 Steam Jet Humidifier [2011A, Ch 47, Fig 29] 292

further reprodu


Figure 23.16

Condenser Water Temperature Control

Automatic Controls

Figure 23.17

Throttling VAV Terminal Unit [2011A, Ch 47, Fig 31]

Figure 23.18 Load and Zone Control in Simple Hydronic System [2011A, Ch 47, Fig 3] 293

further reprodu


Fan-Powered VAV Terminal Unit [2011A, Ch 47, Fig 35]

Automatic Controls

Figure 23.19

Figure 23.20 Duct Heater Control [2011A, Ch 47, Fig 9]

Figure 23.21 Pressure-Independent Dual-Duct VAV Terminal Unit 294

further reprodu


HVAC Systems

Figure 23.22 Zone Mixing Dampers—Three-Deck Multizone System

Automatic Controls

Figure 23.23 Variable-Flow Chilled-Water System (Primary Only) [2011A, Ch 47, Fig 10]

Figure 23.24 Multizone Single-Duct System [2011A, Ch 47, Fig 44] 295

further reprodu


Automatic Controls

Figure 23.25 Dual-Duct Single Supply Fan System [2011A, ch 47, Fig 45]

Figure 23.26 Variable-Flow Chilled-Water System (Primary/Secondary) [2011A, Ch 47, Fig 12]

296

further reprodu


24.

OCCUPANT COMFORT

ASHRAE Standard 55-2010, Thermal Environmental Conditions for Human Occupancy (See complete standard for detailed guidance.)

Acceptable ranges of operative temperature and humidity for people in 0.5 to 1.0 clo clothing, activity between 1.0 met and 1.3 met. The operative temperature ranges are based on a 80% satisfaction criterion; 10% general dissatisfaction and 10% partial (local) dissatisfaction.

temperature, operative (to): the uniform temperature of an imaginary black enclosure in which an occupant would exchange the same amount of heat by radiation plus convection as in the actual nonuniform environment. An acceptable approximation that operative temperature equals air temperature exists when there is no radiant or radiant panel heating or cooling system; there is no major heat generating equipment in the space; the wall/window Uw < 15.8/(tdi – tde), where tdi is the inside design temperature and tde is the outside design temperature; and window solar heat gain coefficient (SHGC) < 0.48. Where air speed is low and tair is closer than 7°F to tmean radiant , the top is their mean value. A computer program is presented in Appendix D of Standard 55-2010 to calculate predicted mean vote (PMV). The PPD (predicted percentage of people dissatisfied) is a function of the PMV.

Occupant Comfort

Figure 24.1 Graphic Comfort Zone Method [Std 55-2010, Fig 5.2.1.1]

Table 24.1 Acceptable Thermal Environment for General Comfort [Std 55-2010, Tbl 5.2.12] PPD < 10

PMV Range –0.5 < PMV < + 0.5 297

further reprodu


Occupant Comfort

Figure 24.2 Air Speed Required to Offset Increased Air and Radiant Temperature [Std 55-2010, Fig 5.2.3.1]

Figure 24.3 Acceptable Range of Operative Temperature and Air Speeds for the Comfort Zone Shown in Figure 24.1, at Humidity Ratio 0.010 [Std 55-2010, Fig 5.2.3.2]

298

further reprodu


Clothing Insulation Values for Typical Ensemblesa [2013F, Ch 9, Tbl 7]

Table 24.2

Icl (clo) 0.57 0.61 0.96 1.14 1.01 1.30 0.54 0.67 1.10 1.04 1.10 0.36 0.72 0.89 1.37 0.74

Clothing Garments Includedb Description 1) Trousers, short-sleeve shirt 2) Trousers, long-sleeve shirt 3) #2 plus suit jacket Trousers 4) #2 plus suit jacket, vest, T-shirt 5) #2 plus long-sleeve sweater, T-shirt 6) #5 plus suit jacket, long underwear bottoms 7) Knee-length skirt, short-sleeve shirt (sandals) 8) Knee-length skirt, long-sleeve shirt, full slip Skirts/ 9) Knee-length skirt, long-sleeve shirt, half slip, long-sleeve sweater Dresses 10) Knee-length skirt, long-sleeve shirt, half slip, suit jacket 11) Ankle-length skirt, long-sleeve shirt, suit jacket Shorts 12) Walking shorts, short-sleeve shirt 13) Long-sleeve coveralls, T-shirt Overalls/ 14) Overalls, long-sleeve shirt, T-shirt Coveralls 15) Insulated coveralls, long-sleeve thermal underwear tops and bottoms Athletic 16) Sweat pants, long-sleeve sweatshirt 17) Long-sleeve pajama tops, long pajama trousers, short 3/4 length robe Sleepwear (slippers, no socks) a b

0.96

Data are from Chapter 9 in the 2013 ASHRAE Handbook—Fundamentals. All clothing ensembles, except where otherwise indicated in parentheses, include shoes, socks, and briefs or panties. All skirt/dress clothing ensembles include pantyhose and no additional socks.

Table 24.3 Percentage Dissatisfied Due to Local Discomfort from Draft (DR) or Other Sources (PD) [Std 55-2010, Tbl 5.2.4] DR Due to Draft < 20%

PD Due to Vertical Air Temperature Difference < 5%

Table 24.4

PD Due to Warm or Cool Floors < 10%

PD Due to Radiant Asymmetry < 5%

Allowable Radiant Temperature Asymmetry [Std 55-2010, Tbl 5.2.4.1] Radiant Temperature Asymmetry °F Cool Wall Cool Ceiling 18.0 25.2

Warm Wall 41.4

Occupant Comfort

Warm Ceiling 9.0

Table 24.5 Allowable Vertical Air Temperature Difference between Head and Ankles [Std 55-2010, Tbl 5.2.4.3] < 5.4

Vertical Air Temperature Difference °F Table 24.6

Allowable Range of the Floor Temperature [Std 55-2010, Tbl 5.2.4.4] 66.2–84.2

Range of Surface Temperature of the Floor °F

Table 24.7 Allowable Cyclic Operative Temperature Variation [Std 55-2010, Tbl 5.2.5.1] 2.0

Allowable Peak-to-Peak Variation in Operative Temperature, °F Table 24.8

Limits on Temperature Drifts and Ramps [Std 55-2010, Tbl 5.2.5.2]

Time Period Maximum Operative Temperature Change Allowed

0.25 h

0.5 h

1h

2h

4h

2.0°F

3.0°F

4.0°F

5.0°F

6.0°F 299

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Occupant Comfort

Figure 24.4 Local Thermal Discomfort caused by Radiant Asymmetry [Std 55-2010, Fig 5.2.4.1]

Figure 24.5

Thermal Comfort in Naturally Ventilated Buildings [Std 55-2010, Fig 5.3]

Calculate the average of the mean minimum and maximum air temperatures for a given month, and then use the chart to determine the acceptable range of indoor operative temperatures for a naturally ventilated building. During the design phase of a building, these numbers could be compared to the output of a thermal simulation model of the proposed building to determine whether the predicted indoor temperatures are likely to be comfortable using natural ventilation, or if air conditioning would be required. The figure also could be used to evaluate the acceptability of thermal conditions in an existing building by comparing the acceptable temperature range obtained from the chart to indoor temperatures measured in the building. The figure is applicable where occupants control operable windows, where activity levels are between 1.0 and 1.3 met, and where occupants may freely adapt their clothing to the indoor and/or outdoor thermal conditions. 300

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25.

GEOTHERMAL SYSTEMS

Ground-Source Heat Pumps Ground-source heat pumps (GSHP) are systems that use the ground, groundwater, or surface water as a heat source and sink. Included under the general term are ground-coupled (GCHP), groundwater (GWHP), and surface water (SWHP) heat pumps. Ground-coupled heat pumps consist of a reversible vapor compression cycle linked to a closed ground heat exchanger buried in soil. The most widely used unit is a water-to-air heat pump, which circulates a water or a water-antifreeze solution through a liquid-to-refrigerant heat exchanger and a buried thermoplastic piping network. Vertical GCHPs generally consist of two small-diameter high-density polyethylene (PE) tubes that have been placed in a vertical borehole that is subsequently filled with a solid medium. The tubes are thermally fused at the bottom of the bore to a close return U-bend. Vertical tubes range from 3/4- to 1 1/2-in. nominal diameter. Bore depths range from 50 ft depending on local drilling conditions and available equipment. A minimum base separation distance of 20 ft is recommended when loops are placed in a grid pattern. The vertical GCHP requires relatively small plots of ground, is in contact with soil that varies very little in temperature and thermal properties, requires the smallest amount of pipe and pumping energy, and can yield the most efficient system performance. The disadvantage is it is typically higher in cost because of expensive equipment needed to drill the borehole and the limited availability of contractors to perform such work. Horizontal GCHPs can be single-pipe, multiple-pipe, and spiral. Multiple pipes (usually two or four) placed in a single trench can reduce the amount of required ground area.

Geothermal Systems

Figure 25.1

Vertical Closed-Loop Ground-Coupled Heat Pump System (Kavanaugh 1985) [2011A, Ch 34, Fig 9] 301

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Geothermal Systems

Advantages of horizontal GCHPs are that they are typically less expensive than vertical GCHPs because relatively low-cost installation equipment is widely available, many residential applications have adequate ground area, and trained equipment operators are more widely available. Disadvantages include, in addition to larger ground area requirement, greater adverse variations in performance because (1) ground temperatures and thermal properties fluctuate with season, rainfall, and burial depth and there are (2) slightly higher pumping energy requirements and (3) lower system efficiencies. Hybrid systems are a variation in which a smaller ground loop is used, which is augmented during the cooling mode by a cooling tower. The ground loop is sized to meet the heating requirements. The downsized loop is used in conjunction with the cooling tower (usually the closed-circuit fluid cooler type) to meet the heat rejection load. Groundwater heat pumps, until the recent development of GCHPs, were the most widely used type. GWHPs can be an attractive alternative because large quantities of water can be delivered from and returned to relatively inexpensive wells that require very little ground area. When the groundwater is injected back into the aquifer by a second well, net water use is zero. A central water-to-water heat exchanger may be placed between the groundwater and a closed water loop which is connected to water-to-air heat pumps located in the building. Under suitable conditions, GWHPs cost less than GCHP equipment, but local environmental regulations may be restrictive, water availability may be limited, fouling precautions may be necessary, and pumping energy may be high. Surface water heat pumps can be either closed-loop systems similar to GCHPs or openloop systems similar to GWHPs. However, the thermal characteristics of surface water bodies are quite different than those of the ground or groundwater.

Figure 25.2 Unitary Groundwater Heat Pump System [2011A, Ch 34, Fig 11] 302

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Figure 25.3

Table 25.1

Horizontal Ground-Coupled Heat Pump Piping [2011A, Ch 34, Fig 11]

Thermal Properties of Selected Soils, Rocks, and Bore Grouts/Fills [2011A, Ch 34, Tbl 5] Dry Density, lb/ft3

Diffusivity, ft2/day

0.8 to 1.1 0.6 to 0.8 0.4 to 0.6 0.3 to 0.5 1.6 to 2.2 1.2 to 1.9 0.6 to 1.2 0.5 to 1.1

0.45 to 0.65 0.5 to 0.65 0.35 to 0.5 0.35 to 0.6 0.9 to 1.2 1.0 to 1.5 0.5 to 1.0 0.6 to 1.3

1.3 to 2.1 1.4 to 2.2 1.2 to 2.0 0.8 to 1.4 0.6 to 1.2

0.9 to 1.4 0.9 to 1.4 0.7 to 1.2 0.7 to 0.9 0.6 to 0.8 Geothermal Systems

Soils Heavy clay (15% water) 120 Heavy clay (5% water) 120 Light clay (15% water) 80 Light clay (5% water) 80 Heavy sand (15% water) 120 Heavy sand (5% water) 120 Light sand (15% water) 80 Light sand (5% water) 80 Rocks Granite 165 Limestone 150 to 175 Sandstone Wet shale 160 to 170 Dry shale Grouts/Backfills Bentonite (20 to 30% solids) Neat cement (not recommended) 20% Bentonite/80% SiO2 sand 15% Bentonite/85% SiO2 sand 10% Bentonite/90% SiO2 sand 30% concrete/70% SiO2 sand, s. plasticizer

Conductivity, Btu/h·ft·°F

0.42 to 0.43 0.40 to 0.45 0.85 to 0.95 1.00 to 1.10 1.20 to 1.40 1.20 to 1.40

Source: Kavanaugh and Rafferty (1997).

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Figure 25.4

Trends of Apparent Thermal Conductivity of Moist Soils [2013F, Ch 26, Fig 6]

Table 25.2 Thermal Resistance of Bores (Rb) for High-Density Polyethylene U-Tube Vertical Ground Heat Exchangers [2011A, Ch 34, Tbl 6] U-tube Diameter, in. 3/4 1 1-1/4

Bore Fill Conductivity,* h·ft·°F/Btu 4 in. Diameter Bore 6 in. Diameter Bore 0.5 0.19 0.17 0.15

1.0 0.09 0.08 0.08

1.5 0.06 0.06 0.05

0.5 0.23 0.20 0.18

1.0 0.11 0.10 0.09

1.5 0.08 0.07 0.06

*Based on DR 11, HDPE tubing with turbulent flow

DR 9 Tubing +0.02 h·ft·°F/Btu

Corrections for Other Tubes and Flows Re = 4000 Re = 1500 +0.008 h·ft·°F/Btu +0.025 h·ft·°F/Btu

Geothermal Systems

Source: Kavanaugh (2001) and Remund and Paul (2000).

304

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Table 25.3 Recommended Lengths of Trench or Bore per Ton for Residential GCHPs [2011A, Ch 34, Tbl 14]

Coil Typea Horizontal 6-Pipe/6-Pitch Spiral 4-Pipe/4-Pitch Spiral 2-Pipe Vertical U-tube 3/4 in. Pipe 1 in. Pipe 1 1/4 in. Pipe

Pitchb Ground Temperature, °F Feet of Pipe per 44 to 47 48 to 51 52 to 55 56 to 59 60 to 63 64 to 67 68 to 70 Feet Trench/ Bore 6 4 2

180 220 300

160 200 280

150 190 250

160 200 280

180 220 300

200 250 340

230 300 400

2 2 2

180 170 160

170 160 150

155 150 145

170 160 150

180 170 160

200 190 175

230 215 200

Source: Kavanaugh and Calvert (1995). aLengths based on DR11 high-density polyethylene (HDPE) pipe. See Figures 21 to 23 for details. b Multiply length of trench by pitch to find required length of pipe. Note: Based on k = 0.6 Btu/h·ft·°F for horizontal loops and k = 1.2 Btu/h·ft·°F for vertical loops. Figures for soil temperatures < 56°F based on modeling using nominal heat pump capacity and assumption of auxiliary heat at design conditions.

Multiply Values by Bold Values Below to Correct for Other Values of Ground Conductivity Ground Thermal Conductivity in Btu/h·ft·°F Coil Typea 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 Horizontal 1.22 1.0 0.89 0.82 — — — — — loop Vertical loop*

—

—

1.23

1.10

1.0

0.93

0.87

0.83

0.79

*Vertical loop values based on an annular fill with k = 0.85 Btu/h·ft·°F. Multiply lengths by 1.2 for kannulus = 0.4 Btu/h·ft·°F and 0.95 for kannulus = 1.1 Btu/h·ft·°F.

Geothermal Systems

305

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Figure 25.5 Residential Design Example [2011A, Ch 34, Fig 24]

Table 25.4 Recommended Residential GCHP Piping Arrangements and Pumps [2011A, Ch 34, Tbl 15]

2

Geothermal Systems

5 to 6 Coil Type* Spiral (10 pt.) 6-Pipe 4-Pipe 2-Pipe Vertical 3/4 in. pipe 1 in. pipe 1 1/4 in. pipe Trench Length Less than 100 ft 100 to 200 ft

3 to 4 3 to 4 2 to 3 2 to 4 2 to 3 2 to 3 1 to 2 1 1/4 1 1/4 1/12 hp (1)

Nominal Heat Pump Capacity, tons 3 4 5 Required Flow Rate, gpm 7 1/2 to 9 10 to 12 12 to 15 Number of Parallel Loops 4 to 6 6 to 9 8 to 10 4 to 6 6 to 9 8 to 10 4 to 6 5 to 8 6 to 9 3 to 5 4 to 6 5 to 8 3 to 5 4 to 6 5 to 8 2 to 4 3 to 5 4 to 6 1 to 2 2 to 3 2 to 3 Header Diameter (PE Pipe), in. 1 1/4 1 1/2 1 1/2 to 2 1 1/2 1 1/2 2 Size (No.) of Pumps Required 1/6 hp (1) 1/12 hp (2) 1/6 hp (2)

6 15 to 18 8 to 10 8 to 10 6 to 10 6 to 10 6 to 10 4 to 6 2 to 4 1 1/2 to 2 2 1/6 hp (2)

Source: Kavanaugh and Calvert (1995). *Based on DR11 HDPE pipe.

306

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Figure 25.6

Lake Loop Piping [2011A, Ch 34, Fig 13]

Closed-loop SWHPs are heat pumps connected to a piping network in a lake or other body of water. A pump circulates water or antifreeze solution through the heat pump water-to-refrigerant heat exchanger and the submerged piping loop, which transfers heat to or from the body of water. The advantages are relatively low cost compared to GCHPs low pumping energy, low maintenance, and low operating cost. Disadvantages are the possibility of coil damage in public lakes and wide variation in water temperature with outdoor conditions if lakes are small and/or shallow. Lake water can be pumped directly to heat pumps or through an intermediate heat exchanger. In deep lakes (40 ft or more), there is often enough thermal stratification throughout the year that direct cooling or precooling is possible. Water can be pumped from the bottom of deep lakes through a coil in the return air duct. Total cooling is a possibility if water is 50°F or below. Precooling is possible with warmer water, which can then be circulated through the heat pump units.

Geothermal Systems

307

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Office Buildings

Dining and Entertainment Centers

General Category

Winter

Noisec

Filtering Efficiencies (ASHRAE Std. 52.1)

NC 35 to 40 35% or better

85 to 88°F

30 to 50 fpm

70 to 74°F 74 to 78°F 25 to 45 fpm 20 to 30% rh 50 to 60% rh 0.75 to 2 cfm/ft2

70 to 74°F

4 to 10

NC 30 to 40 35 to 60% or better

12 to 15g NC 40 to 50 10 to 15% or better

Use charcoal for odor control with manual 70 to 74°F 74 to 78°F below 25 fpm f 20 to 30 NC 35 to 45 purge control for 100% 20 to 30% rh 50 to 60% rh at 5 ft above floor outside air to exhaust ±35% prefilters

Kitchens

Peak at 1 to 2 PM

Peak at 1 to 2 PM

Load Profile

Prevent draft discomfort for patrons waiting in serving lines

Comments

General

Peak at 4 PM

Negative air pressure required for odor control (also see Chapter 31)

Provide good air Nightclubs peak at 8 PM movement but to 2 AM; Casinos peak at prevent cold draft 4 PM to 2 AM; Equipment, discomfort for 24 h/day patrons

Use charcoal for odor Peak at 5 to 7 PM control with manual 15 to 20 NC 35 to 50 purge control for 100% outside air to exhaust ±35% prefilters

8 to 12

12 to 15 NC 40 to 50 e 35% or better

Circulation, ach

Nightclubs and Casinos

30 fpm at 6 ft above floor

25 to 30 fpm


Air Movement

Bars

70 to 74°F 74 to 78°F 20 to 30% rh 55 to 60% rh

78°Fd 50% rh

Summer

General Design Criteriaa, b [2007A, Ch 3, Tbl 1]

70 to 74°F 74 to 78°F 20 to 30% rh 50 to 60% rh

Restaurants

Cafeterias and 70 to 74°F Luncheonettes 20 to 30% rh

Specific Category

Inside Design Conditions

Table 26.1


26. GENERAL


308

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25 to 30 fpm


below 25 fpm

below 25 fpm

Air Movement

8 to 20

10 to 15

8 to 12

8 to 12

Circulation, ach


35% prefilters plus charcoal filters 85 to 95% final i

to NC 60

85% or better

NC 40 to 50 10 to 15%

NC 35

NC 35 to 40 35 to 60% or better

Noisec Load Profile

Constant temperature and humidity required Constant temperature and humidity required

Varies widely because of changes in lighting and people

Comments

Varies with location and use

Peak at 6 to 8 PM

Peak at 3 PM

Peak at 3 PM

General Design Criteriaa, b [2007A, Ch 3, Tbl 1] (Continued)

74 to 78°F 74 to 78°F below 25 fpm at 15 to 40 NC 15 to 25 35% or better 30 to 40% rh 40 to 55% rh 12 ft above floor

72 to 78°F 72 to 78°F 40 to 50% rh 40 to 50% rh

70 to 74°F 75 to 78°F 20 to 30% rh 50 to 55% rh

See Chapter 21

Archival

Summer

68 to 72°F40 to 55% rh

Winter


Average

Specific Category

Telephone Terminal Communication Rooms Centers Radio and Television Studios

Bowling Centers

Museums, Galleries, Libraries, and Archives (also see Chapter 21)

General Category

Table 26.1

General



309

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Warehouses

Transportation Centers (also see Chapter 13)

General Category

Garages

1 to 4

Inside design temperatures for warehouses often depend on the materials stored

8 to 12

8 to 12

8 to 12

Circulation, ach

4 to 6

80 to 100°F

25 to 30 fpm at 6 ft above floor



Air Movement

35% or better and charcoal filters


to NC 75

10 to 35%

NC 35 to 50 10 to 15%

NC 35 to 50 35% with exfiltration

NC 35 to 50 10 to 15%

NC 35 to 50

Noisec Load Profile

Peak at 10 AM to 3 PM





General Design Criteriaa, b [2007A, Ch 3, Tbl 1] (Continued)

30 to 75 fpm

40 to 55°F

70 to 74°F 74 to 78°F 20 to 30% rh 50 to 60% rh

Bus Terminals

j

70 to 74°F 74 to 78°F 20 to 30% rh 50 to 60% rh

Ship Docks

Summer

70 to 74°F 74 to 78°F 20 to 30% rh 50 to 60% rh

Winter

Airport Terminals

Specific Category


Table 26.1


Negative air pressure required to remove fumes; positive air in pressure adjacent occupied spaces

Positive air pressure required in terminal

Positive air pressure required in waiting area

Positive air pressure required in terminal

Comments

General


310

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b Consult

General

table shows design criteria differences between various commercial and public buildings. It should not be used as sole source for design criteria. Each type of data contained here can be determined from ASHRAE Handbook and standards. governing codes to determine minimum allowable requirements. Outside air requirements may be reduced if high-efficiency adsorption equipment or other odor- or gas-removal equipment is used. See ASHRAE Standard 62.1 for calculation procedures. c Refer to Chapter 48 of 2011 ASHRAE Handbook—HVAC Applications. d Food in these areas is often eaten more quickly than in a restaurant; therefore, turnover of diners is much faster. Because diners seldom remain for long periods, they do not require the degree of comfort necessary in restaurants. Thus, it may be possible to lower design criteria standards and still provide reasonably comfortable conditions. Although space conditions of 80°F and 50% rh may be satisfactory for patrons. when it is 95°F and 50% rh outside, inside conditions of 78°F and 40% rh are better. f In some nightclubs, air-conditioning system noise must be kept low so patrons can hear the entertainment. g Usually determined by kitchen hood requirements. h Peak kitchen heat load does not generally occur at peak dining load, although in luncheonettes and some cafeterias where cooking is done in dining areas, peaks may be simultaneous. i Methods for removing chemical pollutants must also be considered. j Also includes service stations. e Cafeterias and luncheonettes usually have some or all food preparation equipment and trays in the same room with diners. These establishments are generally noisier than restaurants, so noise transmission from air-conditioning equipment is not as critical.

a This

Notes to General Design Criteria



311

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Air-Conditioning Formulas 1 Btu = amount of heat required to raise (or lower) temperature of one pound of water 1°F General

1 ton refrigeration = 12,000 Btu/h = 200 Btu/min 1 watt = 3.412 Btu/h 1 horsepower = 2545 Btu/h 1 lb = 7000 grains 1 ft (head) = 0.433 psi 1 square foot EDR (equivalent direct radiation) = 240 Btu 1 boiler horsepower = 33,479 Btu/h No. of air changes (N) = 60 (cfm)/ft3 Sensible heat (Btu/h) = 1.08 Qt where t = difference between entering and leaving dry-bulb temperature and Q = airflow rate in cubic feet per minute Latent heat (Btu/h) = 0.68 Qg where g = difference in moisture content of entering and leaving air, grains per pound of dry air Water quantity (gpm) required for heating and cooling = q/500 twater where q = load in Btu/h Chiller capacity (tons) = gpm (chilled water)  t (water)/24 For Air: 1 lb/h = 4.5 Q 1 ton = Qh/2670 cfm  static pressure (in. w.g.) Density of air Fan hp = -------------------------------------------------------------------------  -----------------------------------------------------6356  Efficiency Density of standard air For water: 1 lb/h = 500 gpm 1 ton = (gpm) t/24 gpm  ft head Pump hp = -------------------------------------------  Specific Gravity 3960  Efficiency small pumps 0.40 – 0.60 efficiency large pumps 0.70 – 0.85 efficiency Control Valves (Cv):

gpm sp gr Liquid: = ---------------------------- p psi  lbsteam/hr  spec vol Steam: = -------------------------------------------------------------63.5  p psi (at 5 psi; specific volume = 20.4, at 30 psi; specific volume = 9.46)

312

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Sizing Formulas

General

Figure 26.1

Sizing Formulas for Heating/Cooling

313

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General

Cooling Tower Performance The curves are based on a typical mechanical-draft, film-filled, cross-flow, medium-sized, air-conditioning cooling tower. The cooling tower, when selected for a specified design condition, operates at other temperature levels when the ambient temperature is off-design or when heat load or flow rate varies from the design condition. When flow rate is held constant, range falls as heat load falls, causing temperature levels to fall to a closer approach. Hot and cold water temperature levels fall when the ambient wet bulb falls at constant heat load, range, and flow rate. As water loading to a particular tower falls at constant ambient wet bulb and range, the tower cools the water to a lower temperature level or closer approach to the wet bulb.

Figure 26.2 Cooling Tower Performance [2012S, Ch 40, Figs 26–29]

Cycles of Concentration =

Evaporation + Drift + Bleed ---------------------------------------------------------------------------Drift + Bleed

Evaporation = 0.8% for 10º range

Drift less than 0.1% 314

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Thermal Storage The primary motivations are to reduce required equipment capacity and to use off-peak or waste energy. General

Heat Storage Radiant floor heating, brick storage air heaters, and water storage heaters can all be used to reduce the size of heating systems and can use off-peak electrical energy to store the heat. Cool Storage Usually either chilled water or ice. Chilled-water storage requires careful tank design and large available space but permits refrigerating system to operate at conventional evaporator temperature at higher efficiency than when making ice. System design should incorporate a high temperature difference across the cooling surface. Tank design should maximize stratification, with inlet and outlet flows at low velocity. Due to the high latent heat of fusion, ice is an excellent storage medium, minimizing storage space. Refrigerating systems must operate at lower evaporating temperature when making ice, thus at lower efficiency. Ice storage systems are usually either external-melt, internal-melt, or ice harvesting.

Figure 26.3

Charge and Discharge of External Melt Ice Storage [2012S, Ch 51, Fig 13]

Figure 26.4 Charge and Discharge of Internal Melt Ice Storage [2012S, Ch 51, Fig 9] 315

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General


Figure 26.5

Ice-Harvesting Schematic (Courtesy Paul Mueller Company) [2012S, Ch 51, Fig 15]

In an external-melt system, refrigerant or a secondary coolant, usually an ethylene glycol solution, is pumped in pipes inside the storage tank. The water freezes outside the pipes and is melted by circulating return water through the tank. In an internal-melt system, the glycol is cooled by a liquid chiller and circulated through coils in a tank to freeze the water in the tank. Since the same heat transfer surface freezes and melts the water, the glycol may freeze the tank’s water completely during the charging cycle, improving efficiency. A temperature-modulating valve at outlet of tank keeps constant flow of glycol solution to the load. In a full-storage system, the chiller is kept off during discharge, and the modulating valve allows enough fluid to bypass the tanks to handle the load. In a partial-storage system, during the discharge cycle the chiller’s supply thermostat is reset from the 22°F needed for charging up to the load’s cooling coil temperature, say 44°F; during low loads, the chiller operates at 44°F without depleting storage; when load exceeds chiller capacity, the leaving glycol temperature rises and the temperature modulating valve opens to maintain the design temperature in the coils. In ice harvesting systems, the ice formation is separate from storage, requiring a defrost cycle to harvest the ice from evaporator plates. ASHRAE Standard 150-2000 provides method of testing of cool storage systems.

316

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Cold-Air Distribution Reducing supply air temperature is attractive, due to the smaller air-handling units and ducts and less space required. This can make cool thermal storage more competitive in initial cost than conventional systems.

Mechanical dehumidifiers remove moisture by passing air over a surface cooled below the air’s dew point and then reheat the air using recovered and recycled energy. Sensible heat ratios are much lower than air conditioners. Compressor starts on a call for dehumidification.

General

Mechanical Dehumidifiers

Figure 26.6 Dehumidification Process Points [2012S, Ch 25, Fig 1]

Figure 26.7 Psychrometric Diagram of Typical Dehumidification Process [2012S, Ch 25, Fig 1] 317

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General

Heat Pipes A heat pipe heat exchanger looks like a finned tube coil, but the tubes are not interconnected and it is divided into evaporator and condenser sections. Warm air passes over evaporator section and cold air over condenser. Each tube has a capillary wick, is evacuated, filled with a refrigerant, and sealed. A vapor pressure gradient drives the vapor to the condenser end of the tube, where it is revaporized, completing the cycle, as long as there is a temperature difference. A wraparound heat pipe removes sensible heat from entering air and transfers it to leaving air. A duct-to-duct or slidein heat pipe has one section in the supply air duct and the other in the return duct. In both configurations air is precooled before entering the system’s cooling coil.

Figure 26.8 Dehumidification Enhancement with Wraparound Heat Pipe (Kittler 1996) [2012S, Ch 25, Fig 13]

Figure 26.9

Heat Pipe Operation [2012S, Ch 26, Fig 17]

318

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General

Figure 26.10 Heat Pipe Exchanger Effectiveness (Ratio of temperature drop of precooled air to difference between the entering air and evaporative refrigerant.) [2012S, Ch 26, Fig 18]

Figure 26.11

Heat Pipe Assembly [2012S, Ch 26, Fig 16]

319

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General

Air-to-Air Energy Recovery Recovering sensible heat and/or moisture from an airstream at high temperature or humidity to an airstream at low temperature or humidity can be accomplished by sensible heat exchange devices (heat recovery ventilation, HRVs) or energy or enthalpy devices that transfer both heat and moisture (ERVs). Types include cross-flow air-to-air heat exchangers, rotary wheels, heat pipes, runaround loops, thermosiphons, and turn-tower enthalpy recovery loops.

Figure 26.12 Fixed-Plate Cross-Flow Heat Exchanger [2012S, Ch 26, Fig 4]

Figure 26.13

Variation of Pressure Drop and Effectiveness with Airflow Rates for a Membrane Plate Exchanger [2012S, Ch 26, Fig 4]

320

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General

Figure 26.14 Coil Energy Recovery Loop [2012S, Ch 26, Fig 14]

Figure 26.15 Twin-Tower Enthalpy Recovery Loop [2012S, Ch 26, Fig 25] 321

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Table 26.2

Comparison of Air-to-Air Energy Recovery Devices [2012S, Ch 26, Tbl 3]

General

Fixed Plate Airflow arrangements

Membra ne Plate

Energy Wheel

Heat Wheel

Heat Pipe

Runaround ThermoCoil Loop siphon

Twin Towers

Counterflow Counterflow Counterflow Counterflow Counterflow Cross-flow Cross-flow Parallel flow Parallel flow

—

Counterflow Parallel flow

—

50 to 74,000 and up

100 and up

100 and up

100 and up

—

Equipment size range, cfm

50 and up

50 and up

50 to 74,000 and up

Typical sensible effectiveness (ms = me), %

50 to 80

50 to 75

50 to 85

50 to 85

45 to 65

55 to 65

40 to 60

40 to 60

Typical latent effectiveness,* %

—

50 to 72

50 to 85

0

—

—

—

—

Total effectiveness,* %

—

50 to 73

50 to 85

—

—

—

—

—

Face velocity, fpm

200 to 1000

200 to 600

500 to 1000

400 to 1000

400 to 800

300 to 600

400 to 800

300 to 450

Pressure drop, in. of water

0.4 to 4

0.4 to 2

0.4 to 1.2

0.4 to 1.2

0.6 to 2

0.6 to 2

0.6 to 2

0.7 to 1.2

EATR, %

0 to 5

0 to 5

0.5 to 10

0.5 to 10

0 to 1

0

0

0

OACF

0.97 to 1.06

0.97 to 1.06

0.99 to 1.1

1 to 1.2

0.99 to 1.01

1.0

1.0

1.0

Temperature range, °F

–75 to 1470

15 to 120

–40 to 105

–50 to 930

–40 to 105

–40 to 115

–65 to 1470

–65 to 1470

Typical mode of purchase

Exchanger Exchanger only only Exchanger in Exchanger in case case Exchanger Exchanger and external and blowers blowers Complete Complete system system

Exchanger only Exchanger in case Exchanger and blowers Complete system

Exchanger only Exchanger in case Exchanger and blowers Complete system

Exchanger only Exchanger in Coil only case Complete Exchanger system and blowers Complete system

Exchanger only Complete Exchanger in system case

Advantages

No moving parts Low pressure drop Easily cleaned

Moisture or mass transfer Compact large sizes Low pressure drop Available on all ventilation system platforms

Compact large sizes Low pressure drop Easily cleaned

No moving parts except tilt Fan location not critical Allowable pressure differential up to 2 psi

Exhaust airstream can be separated from supply air Fan location not critical

No moving parts Exhaust airstream can be separated from supply air Fan location not critical

Latent transfer from remote airstreams Efficient microbiological cleaning of both supply and exhaust airstreams

Limitations

Supply air Few suppliers may require Long-term some further Large size at Some EATR maintenance cooling or higher flow without and perforheating rates purge mance Some EATR unknown without purge

Effectiveness limited by pressure drop and cost Few suppliers

Predicting performance requires accurate simulation model

Effectiveness may be limited by pressure drop and cost Few suppliers

Few suppliers Maintenance and performance unknown

No moving parts Low pressure drop Low air leakage

Bypass Bypass Bypass Heat rate control dampers and dampers and dampers and (HRC) methods wheel speed ducting ducting control

Bypass dampers and wheel speed control

Control valve Tilt angle Bypass valve Control valve or pump down to 10% or pump over full speed control of maximum speed control range over full heat rate range

*Rated effectiveness values are for balanced flow conditions. Effectiveness values increase slightly if flow rates of either or both airstreams are higher than flow rates at which testing is done. EATR = Exhaust Air Transfer Ratio OACF = Outdoor Air Correction Factor

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Panel Heating and Cooling ta = AUST =

Typical panels, floor, or ceiling have hydronic tubes or electric cables embedded in, attached to or integral with the floor or ceiling. Surface temperature of floor panels should not exceed 84°Ffor comfort; and surface temperature of ceiling panels should not be lower than 1°F above design air dew-point temperature to avoid condensation. Panel cooling is usually a supplement to cooling and dehumidification by an air supply system.

General

air temperature in conditioned space, °F average unheated (uncooled) temperature of surfaces directly exposed to the panel; typically 1°F higher than ta in cooling; 2°F lower than ta in heating. Typical design ta = 68°F in heating, 76°F in cooling.

In Figure 26-17: tp = panel surface temperature, °F tw = average heating (cooling) fluid temperature, °F (for electric systems = skin temperature of cable) qu = heat flux up, Btu/h·ft2 qd = heat flux down, Btu/h·ft2 M = tube (cable) spacing, ft ru = characteristic (combined) panel thermal resistance, ft2 ·h·°F/Btu·ft rc = thermal resistance of panel surface covers such as carpet rp = thermal resistance of panel body rt = thermal resistance of tube wall per unit tube spacing rs = thermal resistance between tube (electric cable) and panel body per unit spacing between tubes (cables); negligible if embedded. ru = rtM + rsM + rp + rc For copper tubes secured to aluminum ceiling panels ru = 0.25 M (approximately).

Figure 26.16 Primary/Secondary Water Distribution System with Mixing Control [2012S, Ch 6, Fig 11] 323

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General


Figure 26.17 Design Graph for Sensible Heating and Cooling with Floor and Ceiling Panels [2012S, Ch 6, Fig 9]

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Variable Refrigerant Flow

General

Variable-refrigerant-flow (VRF) HVAC systems are a direct-expansion (DX) heat pump technology platform built on the standard reverse Rankine vapor compression cycle. These systems are thermodynamically similar to unitary and other common DX systems, and share many of the same components (i.e., compressor, expansion device, and heat exchangers). VRF systems transport heat between an outdoor condensing unit and a network of indoor units located near or within the conditioned space through refrigerant piping installed in the building. Attributes that distinguish VRF from other DX system types are multiple indoor units connected to a common outdoor unit (single or combined modules), scalability, variable capacity, distributed control, and simultaneous heating and cooling. VRF systems are highly engineered, with single or multiple compressors, multiple indoor units (ducted and nonducted types), and oil and refrigerant management and control components. VRF provides flexibility by allowing for many different indoor units (with different capacities and configurations), individual zone control, and the unique ability to offer simultaneous heating and cooling in separate zones on a common refrigerant circuit, and heat recovery from one zone to another. Typical capacities range from 18,000 to 760,000 Btu/h for outdoor units and from 5000 to 120,000 Btu/h for indoor units. Many VRF systems are equipped with at least one variable-speed and/or variable-capacity compressor; the compressor varies its speed to operate only at the levels necessary to maintain indoor environments to the specified requirements. System Types There are three basic types of VRF systems: cooling only (Figure 26.18), heat pump, and heat recovery (Figures 26.19 and 26.20). Heat pumps are air-conditioning systems capable of reversing the direction of the refrigerant flow to provide heating or cooling to the indoor space. All indoor units connected to a heat pump system can use individual control and set points, but they operate in the same mode of either heating or cooling at any given time. Heat recovery units are heat pump systems that can provide simultaneous heating and cooling. All indoor units connected to a heat recovery system not only can use individual control and set points, but they can also individually operate in heating or cooling mode at any given time. To match the building’s load profiles, energy is transferred from one indoor space to another through the refrigerant line, and only one energy source is necessary to provide both heating and cooling. VRF systems also operate efficiently at part load because of the compressor’s variable capacity control. The following definitions are based on AHRI Standard 1230. A heat pump multisplit system is an encased, factory-made, permanently installed assembly that takes heat from a heat source and delivers it to the conditioned space when heating is desired. It may remove heat from the conditioned space and discharge it to a heat sink if cooling and dehumidification are desired from the same equipment. Normal components include multiple indoor

Figure 26.18

Cooling-Only Heat Pump VRF System [2012S, Ch 18, Fig 2] 325

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General


Figure 26.19

Figure 26.20

Two-Pipe Heat Recovery VRF System [2012S, Ch 18, Fig 3]

Three-Pipe Heat Recovery VRF System Examples [2012S, Ch 18, Fig 4]

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General

conditioning coils, compressor(s), and outdoor coil(s). Equipment may be provided in multiple assemblies, intended for use together. Other functions may include cleaning, circulating, and humidifying the air. A VRF multisplit system is a split-system air conditioner or heat pump with a single refrigerant circuit, one or more outdoor units, at least one variable-speed compressor or other compressor combination that can vary system capacity by three or more steps, and multiple indoor fan-coil units that are individually metered and individually controlled by an integrated control device and common communications network. A VRF heat recovery multisplit system operates as an air conditioner or as a heat pump, and also can provide simultaneous heating and cooling operation by transferring recovered energy from the indoor units operating in one mode to other indoor units operating in the other mode. Variable refrigerant flow implies three or more steps of control on common, interconnecting piping. Safety Considerations for Refrigerants As with any HVAC equipment, VRF systems must include design and application safeguards that protect occupants. ASHRAE Standard 15 applies to the design, construction, testing, installation, operation, and inspection of mechanical refrigeration systems. This standard specifies safe design, construction, installation, and operation of refrigeration systems. Many national, state, and local building codes require compliance with Standard 15 or with similar requirements Designers also need to refer to ASHRAE Standard 34, which lists the most current information related to refrigerant designations, safety classifications, and refrigerant concentration limits (RCL). ASHRAE Standard 34 refers to common names of refrigerants used in HVAC systems, instead of using the chemical name, formula, or trade name. The standard establishes a uniform system for assigning reference numbers and safety classifications to refrigerants (including blends). To successfully apply ASHRAE Standard 15 to a project, the designer must know the following:

.

• • • • •

Classification and RCL of the refrigerant used Classification of occupancy type in which the indoor unit and/or piping will be located Total amount of refrigerant used in the system Individual occupied zone(s) geometry and connected zones, if applicable Methodology to calculate the maximum amount of refrigerant that can be safely dispersed into a specific zone

The smallest space in which any of the indoor units or piping could be located must be capable of safely dispersing the refrigerant charge of the entire VRF system in the unlikely event of a catastrophic leak or failure. Examples of spaces that may require additional consideration include • Bathrooms • Electrical rooms • Closets • Small offices • Egress Several options are available to manage smaller spaces; however, care is needed not to violate other local or national codes such as NFPA Standard 70. Options available to manage smaller spaces where the RCL would otherwise be exceeded include the following: • Do not install an indoor unit, but allow the code-required ventilation to maintain conditions in the space. • If cooling is required in the occupied space, one option is to increase the actual space volume by providing a permanent opening or connecting to an adjacent room, as described in ASHRAE Standard 15. A permanent opening can be included along the common wall between an electrical room and janitor closet to increase the size of the space; alternatively, install the ceiling high enough to provide the necessary volume, or omit the ceiling entirely. • A ducted indoor unit could serve several smaller offices, thus increasing the overall occupied space served by the system. • Central VRF systems can be subdivided into a series of smaller systems so that the total charge in a given system does not exceed the RCL limitations for a given space. In summary, meeting ASHRAE Standard 15 requirements may only need simple adjustments to the project’s design: carefully considering the building’s zones, determining connected spaces, and optimally placing the piping and indoor units. With sound engineering practices, a VRF system can be designed to comply with Standard 15 and all other applicable code requirements. 327

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Units and Conversions Table 26.3 Conversions to I-P and SI Units [2013F, Ch 38, Tbl 1] General

(Multiply I-P values by conversion factors to obtain SI; divide SI values by conversion factors to obtain I-P)

Multiply I-P

By

To Obtain SI

acre (43,560 ft2) ........................................................................................ ................................................................................................................... atmosphere (standard) ............................................................................... bar ............................................................................................................. barrel (42 U.S. gal, petroleum) ................................................................. ................................................................................................................... Btu (International Table) ........................................................................... Btu (thermochemical) .............................................................................. Btu/ft2 (International Table)...................................................................... Btu/ft3 (International Table)...................................................................... Btu/gal....................................................................................................... Btu·ft/h·ft2 · °F .......................................................................................... Btu·in/h·ft2 · °F (thermal conductivity k) .................................................. Btu/h.......................................................................................................... Btu/h·ft2 .................................................................................................... Btu/h·ft2 · °F (overall heat transfer coefficient U) ..................................... Btu/lb......................................................................................................... Btu/lb·°F (specific heat cp) ....................................................................... bushel (dry, U.S.) ...................................................................................... calorie (thermochemical) .......................................................................... centipoise (dynamic viscosity ) .............................................................. centistokes (kinematic viscosity ) ........................................................... clo.............................................................................................................. dyne........................................................................................................... dyne/cm2 ................................................................................................... EDR hot water (150 Btu/h) ....................................................................... EDR steam (240 Btu/h)............................................................................. EER ........................................................................................................... ft ................................................................................................................ ................................................................................................................. ft/min, fpm ................................................................................................ ft/s, fps....................................................................................................... ft of water .................................................................................................. ft of water per 100 ft pipe.......................................................................... ft2............................................................................................................... ft2 ·h· °F/Btu (thermal resistance R) .......................................................... ft2/s (kinematic viscosity ) ...................................................................... ft3............................................................................................................... ............................................................................................................... ft3/min, cfm ............................................................................................... ft3/s, cfs ..................................................................................................... ft·lbf (torque or moment) .......................................................................... ft·lbf (work) .............................................................................................. ft·lbf /lb (specific energy).......................................................................... ft·lbf /min (power)..................................................................................... footcandle.................................................................................................. gallon (U.S., *231 in3) .............................................................................. gph............................................................................................................. gpm ........................................................................................................... gpm/ft2 ...................................................................................................... gpm/ton refrigeration ................................................................................ grain (1/7000 lb) ....................................................................................... gr/gal ......................................................................................................... gr/lb ........................................................................................................... horsepower (boiler) (33,470 Btu/h) .......................................................... horsepower (550 ft·lbf /s) .......................................................................... inch............................................................................................................ in. of mercury (60°F) ................................................................................ in. of water (60°F)..................................................................................... in/100 ft, thermal expansion coefficient....................................................

0.4047 4046.873 *101.325 *100 159.0 0.1580987 1055.056 1054.350 11,356.53 37,258.951 278,717.1765 1.730735 0.1442279 0.2930711 3.154591 5.678263 *2.326 *4.1868 0.0352394 *4.184 *1.00 *1.00 0.155 1.0  10–5 *0.100 43.9606 70.33706 0.293 *0.3048 *304.8 *0.00508 *0.3048 2989 98.1 0.092903 0.176110 92,900 28.316846 0.02832 0.471947 28.316845 1.355818 1.356 2.99 0.0226 10.76391 3.785412 1.05 0.0631 0.6791 0.0179 0.0648 17.1 0.143 9.81 0.7457 *25.4 3.3864 248.84 0.833

ha m2 kPa kPa L m3 J J J/m2 J/m3 J/m3 W/(m·K) W/(m·K) W W/m2 W/(m2 ·K) kJ/kg kJ/(kg·K) m3 J mPa·s mm2/s (m2 ·K)/W N Pa W W COP m mm m/s m/s Pa Pa/m m2 (m2 ·K)/W mm2/s L m3 L/s L/s N·m J J/kg W lx L mL/s L/s L/(s·m2) mL/J g g/m3 g/kg kW kW mm kPa Pa mm/m

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Table 26.3

Conversions to I-P and SI Units [2013F, Ch 38, Tbl 1] (Continued)

(Multiply I-P values by conversion factors to obtain SI; divide SI values by conversion factors to obtain I-P)

By

in·lbf (torque or moment) ....................................................................... in2 ........................................................................................................... in3 (volume) ............................................................................................ in3/min (SCIM)....................................................................................... in3 (section modulus).............................................................................. in4 (section moment) .............................................................................. kWh ........................................................................................................ kW/1000 cfm .......................................................................................... kilopond (kg force) ................................................................................. kip (1000 lbf) .......................................................................................... kip/in2 (ksi) ............................................................................................. litre.......................................................................................................... met .......................................................................................................... micron (m) of mercury (60°F).............................................................. mile ......................................................................................................... mile, nautical .......................................................................................... mile per hour (mph) ................................................................................ ........................................................................................................... millibar.................................................................................................... mm of mercury (60°F)............................................................................ mm of water (60°F) ................................................................................ ounce (mass, avoirdupois) ...................................................................... ounce (force or thrust) ............................................................................ ounce (liquid, U.S.)................................................................................. ounce inch (torque, moment).................................................................. ounce (avoirdupois) per gallon ............................................................... perm (permeance at 32°F) ...................................................................... perm inch (permeability at 32°F) ........................................................... pint (liquid, U.S.).................................................................................... pound lb (avoirdupois, mass)............................................................................. ........................................................................................................... lbf (force or thrust).................................................................................. lbf /ft (uniform load) ............................................................................... lb/ft·h (dynamic viscosity ) .................................................................. lb/ft·s (dynamic viscosity ) .................................................................. lbf ·s/ft2 (dynamic viscosity ) ............................................................... lb/h .......................................................................................................... lb/min...................................................................................................... lb/h [steam at 212°F (100°C)] ................................................................ lbf /ft2....................................................................................................... lb/ft2 ........................................................................................................ lb/ft3 (density ) ..................................................................................... lb/gallon .................................................................................................. ppm (by mass) ........................................................................................ psi............................................................................................................ quad (1015 Btu)....................................................................................... quart (liquid, U.S.).................................................................................. square (100 ft2) ....................................................................................... tablespoon (approximately) .................................................................... teaspoon (approximately) ....................................................................... therm (U.S.) ............................................................................................ ton, long (2240 lb) .................................................................................. ton, short (2000 lb) ................................................................................. ton, refrigeration (12,000 Btu/h)............................................................. torr (1 mm Hg at 0°C) ............................................................................ watt per square foot ................................................................................ yd ............................................................................................................ yd2........................................................................................................... yd3...........................................................................................................

113 645.16 16.3874 0.273117 16,387 416,231 *3.60 2.118880 9.81 4.45 6.895 *0.001 58.15 133 1.609 *1.852 1.609344 0.447 *0.100 0.133 9.80 28.35 0.278 29.6 7.06 7.489152 5.72135  10–11 1.45362  10–12 4.73176  10–4

To Obtain SI mN·m mm2 mL mL/s mm3 mm4 MJ kJ/m3 N kN MPa m3 W/m2 mPa km km km/h m/s kPa kPa Pa g N mL mN·m kg/m3 kg/(Pa·s·m2) kg/(Pa·s·m) m3

0.453592 453.592 4.448222 14.59390 0.4134 1490 47.88026 0.000126 0.007559 0.2843 47.9 4.88 16.0 120 *1.00 6.895 1.055 0.9463 9.2903 15 5 105.5 1.016046 0.907184 3.517 133 10.76 *0.9144 0.8361 0.7646

kg g N N/m mPa·s mPa·s Pa·s kg/s kg/s kW Pa kg/m2 kg/m3 kg/m3 mg/kg kPa EJ L m2 mL mL MJ Mg Mg; t (tonne) kW Pa W/m2 m m2 m3

General

Multiply I-P

*Conversion factor is exact. Notes: 1. Units are U.S. values unless noted otherwise. 2. Litre is a special name for the cubic decimetre. 1 L = 1 dm3 and 1 mL = 1 cm3. 329

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INDEX air air-conditioning formulas 308 air-conditioning processes 16 contaminants 36–37 density 19 enthalpy 18 filters 37–39 friction chart 1 psychrometric chart 15 air quality standards 36 air conditioning cooling load check figures 172 CLTD values 171, 185–88 glass, sunlit 189 shading coefficients 190 air diffusion ADPI 29–30 fully stratified systems 31–32 jet behavior 22–24 mixed-air systems 26–28 outlet performance 26–28, 34 partially mixed systems 33 return air design 35 air quality clean spaces 55 pollutant sources 40 standards 36 ventilation rate 208 air spaces attics 178 emittances 176 thermal resistance 176 air-to-air energy recovery 316–18 ammonia line capacities 152–53 thermodynamic properties 121 ASHRAE Standard 62.1-2010 209–23 ASHRAE Standard 62.2-2010 208 combined heat and power 240 combustion turbines 246 comfort air speed 294 clothing insulation 295 local discomfort 295–96 operative temperature 293 conductivity building materials 179–84 insulation 179 soils 299–300 contaminants air quality standards 36 sources 40 controls systems and terminals 284–92 conversion factors 324–25 cooling load 170, 173 cooling tower 285, 310

costs life cycle 256 maintenance 253–54 owning and operating 255 desiccant cycle 234 equipment 235–39 diffusion 20 duct circular equivalents 6–7 component velocities 9 friction chart 1 velocities vs. velocity pressures 2 electrical formulas 231 energy efficiency standards 228 system design 227 engines fuels 251–52 heat balance 243 maintenance 241 sizing 241 waste heat 243–44 equipment costs 255 noise from 265 evaporative cooling 279 exhaust ventilation capture velocities 47 hoods 50–54 transport velocities 49 fans fan laws 10–11 fan noise 266 types 12–13 filters design velocity 9 electronic 37 installation 37 standards 37–39 fittings, for HVAC applications 89–90 formulas air conditioning 308 electrical 231 water 57 water flow for heating/cooling 309 friction chart air 1 water 66–68 fuel cells 247–48 fuel oil data 252 gas pipe sizing 249 glass conductivity 147 shading, coefficients 190 solar heat gain 191–207 glycols, freezing point of 63

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heat gains laboratory equipment 202–203 lighting 192–94 motors, electric 195–96 office equipment 204–207 people 191 restaurant equipment 197–201 heat pipes 314–15 heat transmission coefficients air space 175 building materials 179–83 fenestration 174 insulation 179 surface conductances 176 hoods kitchen ventilation 51–53 laboratory 54 insulation spaces 175 thermal values for 179 louvers 9 motors characteristics 230 full-load amperes 231 heat gain from 195–96 panel heating and cooling 319 photovoltaic systems 233 piping applications 89 copper 66 expansion, thermal 91 friction loss, water 66–68 fuel oil 252 gas 249 plastic 67 refrigerant capacities 136–47, 152 steam capacity 78–79 steel 68 volume of water in 65 psychrometric chart 15 pump affinity laws 57 net positive suction head 59 power 309 terms 57 typical curves 61 refrigerants line capacities R-134a 146–47 R-22 144–45 R-404A 136–137 R-407C 142–43 R-410A 140–41 R-507A 138–39 R-717 (ammonia) 152, 153 thermodynamic properties R-123 116

R-1234yf 131 R-1234ze(E) 133 R-134a 118–19 R-22 113–14 R-404A 123 R-407C 125 R-410A 127 R-507A 129 R-717 (ammonia) 121 refrigerated display fixtures 207 refrigeration cycle 106 refrigeration load 165–68, 174 refrigerant safety 155 service water heating 93 soils thermal properties 299 solar energy 101–105 sound equipment noise 266 fan noise 266 HVAC acceptable 261 pressure 258–59 rating methods 262–63 NC curves 262 RC curves 263 space air diffusion 20–21 steam flow rate for heating/cooling 77 pipe capacities 78–79 pressure-enthalpy diagram 76 properties 75 sustainability 227 system design criteria 304–307 tanks, cylindrical capacity of horizontal 64 volume 64 thermal storage 311 turbines combustion 246 steam 245 ultraviolet lamp systems 45–46 variable refrigerant flow 321 variable-speed drives 232 ventilation requirements 208–223 vibration 267 vibration isolators 268–278 water demand, hot 96 fixture and demand 97 mass flow vs. temperature 63 pipe sizing 309 pumps 57–61 specific heat 63 viscosity 62 volume in pipe 65 331

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ASHRAE Pocket Guide IP 8th edition 2013.pdf

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