HVAC Load Explorer p V1.0 http://www.mae.okstate.edu/hvac/ p Dr. Ahmed Farouk Elsafty Mechanical and Marine Eng. Dept. College of Engineering and Technology Arab Academy for Science, Technology and Maritime Transport Email:
[email protected]
Content Notes • • • • • • • • • • • • • • • • •
Minimum Requirements Weather data (explain selection and non-July) Zoning (“rooms”) Geometric description (inside dimensions or outside dimensions? Also simplification.) M t i l properties Material ti (i (include l d radiative di ti properties) ti ) Describing walls and roofs. Describing stud walls. How to describe attic type spaces. Describing windows Describing doors Internal heat gains (levels and schedules) D Describing ibi th thermall mass Infiltration and Ventilation Specifying system parameters Practical things about program –why why does it do backup instead of save? How to get output. Download latest version from website. Heating Load Calculations Check end of chapter for other items?
Minimum System Requirements * Windows 95 * Pentium Pentium-compatible compatible processor running at 100 MHz or faster * 32MB RAM * Hard drive with at least 30MB free space * SVGA monitor,, 800 x 600 * Windows-compatible mouse or pointing device * CD-ROM drive * Adobe Acrobat(tm) Reader 3 (Adobe Acrobat Reader 4.0 included on CD)
HVAC Load Explorer • This software uses the heat balance methods • Developed under ASHRAE Research Project 875 875, for calculating cooling/heating loads in building. • The heat balance method is the most scientifically precise method now available.
Heat Balance Method • Based on heat balances for exterior zone surfaces, interior zone surfaces, and zone air. air • Assures conservation of energy (which is not guaranteed for approximate methods).
LW Long Wave SW Short Wave
Software Setup • Start your computer. computer If your computer is already running, running close all applications. • Insert the CD-ROM in yyour CD-ROM drive • In Windows Explorer, locate the CD-ROM drive and go into the directory containing the program that you wish to install. install • Double-click on the file "Setup.exe". • Follow the instructions in the installer. (This may require re-booting b i your computer.)) • If you do not have Adobe Acrobat, use the Windows Explorer to find the root directory of the CD. DoubleDouble click on the file "ar40eng.exe" and follow the instructions. • Restart your computer.
Try now to Run the program Unfortunately, the program will not RUN !!!! Y need You d to t gett some files fil to t solve l this thi problem
HVAC Load Explorer • • • • •
Summary of Revisions and Known Bugs (New: 2-21-03) 2 21 03) Load Calculations Seminar (New 10-17-03) Download latest version (1.0.19, (1 0 19 October 29, 29 2003) If you have installed the software from the CD, and have not previously downloaded any of the software, you will need to download the files listed below. You should right-click on each file name and choose "Save Target A " (in As" (i Mi Microsoft ft Explorer) E l ) or "Save "S Link Li k A As"" (i (in N Netscape), t ) th then save th the file in a temporary directory. When all files have been downloaded, you should copy the files into the specified directories. (Most will go into the HVACLoadExplorer directory; TimeZone.txt must be copied into the textfiles di directory, under d your main i HVACL HVACLoadExplorer dE l di directory.template.mdb l db must be copied into the Database directory, under your main HVACLoadExplorer directory.) If you have already downloaded a previous version from this website, you should check the dates on the files below. Any files listed below that are newer than the files on your hard drive should be downloaded.
Download: File Name
Date
Directory
HvacLoadExplorer.exe
(New 10-29-03)
HVAC Load Explorer
HVACLOADEXPLORE R.HLP
(New 10-29-03)
HVAC Load Explorer
HvacLoadExplorer cnt HvacLoadExplorer.cnt
(New 10 10-29-03) 29 03)
HVAC Load Explorer
HBFORT15.dll
(New 2-21-03)
HVAC Load Explorer
DFORRT.DLL
(New 6-1-00)
HVAC Load Explorer
TimeZone.txt
(New 12-1-00)
HVAC Load Explorer\textfiles p
template.mdb
(New 4-28-03)
HVAC Load Explorer\database
Add d Addendum.pdf df
(N 22-21-03) (New 21 03)
*
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Note: (4 (4-1-03) 1 03) Some computers may also need an additional file file, mschrt20.ocx. Solution : Computers that do not already have the file mschrt20.ocx mschrt20 ocx will need to download the file, and then store it in the following directory, depending on your operating system: Windows 95/98 - C:\WINDOWS\system Windows NT/2000 - C:\WINNT\system32 y Windows Me - C:\WinMe\System Windows Xp - C:\WINDOWS\system32 To download the file,, right-click g on the link above and choose "Save Target As" (in Microsoft Explorer) or "Save Link As" (in Netscape)
Download a Sample File • Thi This fil file can b be used d tto calculated l l t d th the conduction transfer function coefficients for Example 8-1: Example 8-1.mdb • The 9 room Chicago g office building g ((see Load Calculations Seminar) is here. • Bug Reports • Bugs should be reported to Prof. J.D. Spitler at
[email protected] spitler@okstate ed
Load Calculations Heat Balance Method -Application Application
Weather Data: Cooling Three types Th t off design d i days d • Based on p peak dry y bulb temperature: p room loads. • Based on peak wet bulb: cooling towers towers, evaporative coolers, ventilation • Based on peak dew dew-point: point: humidity control. • See 2001 ASHRAE Handbook of Fundamentals for further information.
Weather Data: Cooling • Month: Usually July July, but not always always. • Some rooms can have peak loads in other months, th even JJanuary. • Example: a p e Sout South facing ac g hotel ote rooms oo s with t large windows may have peak loads in January. January
South-Facing South Facing Window
• Simple scheme: window collects energy energy, insulation does not let it go, thermal mass stabilizes against large fluctuations – overhang defeats mechanism for summer months
Zoning/Rooms In HVAC Load Explorer terminology: • Room: one or more rooms with similar temperatures, loading, and controls. – IIn large l b ildi buildings, it may be b desirable d i bl tto combine bi multiple rooms into a single room description. – (Often called a zone in heat balance literature literature.))
• Zone: provided in HVAC Load Explorer for convenience; i it iis a way off adding ddi up lloads d ffor a group of rooms. (e.g. All rooms served by a single i l air i h handler) dl )
Dimensions • Outside or Inside? • Corner effects are usually small small, hence it doesn’t make that much difference. • Inside I id dimensions di i may slightly li htl underestimate load. • Outside dimensions may slightly overestimate load load. • Simplify geometry when possible.
Describing Walls and Roofs • Described layer by layer from the outside in. properties p for each layer y ((k, ρ, ρ cp) p) from • Material p MPS 127-132 • Solar absorptivity and thermal emissivity important for inside and outside layers. • Do not specify surface conductances in heat balance method. • Surface tilt and orientation must be specified for solar radiation purposes.
Zone North Axis:
Wall Information Dialog Box • Tilt is the angle made by the wall with the g horizontal in degrees. • Default is 90o.
90o
Elevation
Wall Information Dialog Box Facing F i direction di ti iis th the angle l made d b by the normal vector of wall with the north in the clockwise direction north, direction, in degrees.
N
W
– Default is 0 0°(facing (facing north) north). – East facing wall will have facing direction of 90°,, – South facing wall will have facing direction of 180°. – West facing direction will have facing direction 270°.
E S
Roof and floor Information – Roof R f default d f lt is i 0°. 0°
Roof 0°
– Floor of 180 180°.
Floor 180°
External Boundary Condition IImportant!! • TOS: normal outside conditions • TA: conditioned space on other side • TG: TG ground d temperature t t on other side • TSS: outside temperature, p , but no sun • TB: special, user-defined boundary temperature on other side.
Thermal mass • Represents interior furnishings, interior partitions not elsewhere described. p • Necessarily approximate. • Has H ttwo effects: ff t – Thermal storage g ((slows room response) p ) – Radiative/convective exchange (speeds room response)
Example
