SAUDI ARAMCO HVAC CALCULATIONS FOR SWITCHGEAR BUILDING – SABKHA 113 SHAYBAH PREPARED BY:
GULF CO-OPERATION SYMBOLS CONT. CO. LTD AL-KHOBAR, SAUDI ARABIA OCTOBER 2012
D
12 October 2012
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________________________________________________________________________________________________________ PETROCON ARABIA LIMITED
TABLE OF CONTENTS
ITEM NO.
TITLE
PAGE
1.0 HVAC DESIGN DATA........................................................................................................................... 2 2.0 BUILDING HEAT LOAD CALCULATION..............................................................................................3 3.0 COOLING AND HEATING LOAD CALCULATION RESULTS............................................................10 4.0 AIR CONDITIONING UNIT SELECTION..............................................................................................11 5.0 ELITE CALCULATION......................................................................................................................... 11 1.0
HVAC DESIGN DATA
1.1
DESIGN CONDITIONS: Location
Shaybah, Saudi Arabia
Latitude / Longitude
22 º 21' North / 54 º 03' East
Elevation @ mean sea level
230 ft
Mean Daily Range
22 oF
Prevailing Wind Direction
from North North East - (NNE)
Wind Velocity 3-sec gust
90 Mph
Cooling Load Calculations in accordance with SAES - A – 112 & SAES-K – 001: OUTSIDE DESIGN CONDITIONS WHOLE BUILDING CONDITION
SUMMER O
DB F
MEAN COINCIDENT WB OF
WINTER DB OF
CONDITION 1 SAES-K-001 Sect. 4.2.1.4
115
70
50
CONDITION 2 SAES-K-001 Sect. 4.2.1.5
100
73
50
INSIDE DESIGN CONDITIONS
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Room Name
Temperature O F
Relative Humidity %
Switchgear Room
75
50
Mechanical Room
75
50
Battery Room
72
50
2.0 BUILDING HEAT LOAD CALCULATION 2.1 EXTERNAL HEAT LOAD 2.1.1
ROOF OVERALL HEAT TRANSFER COEFFICIENT - "U" VALUE (GROUND FLOOR)
MATERIAL CONSTRUCTION (FROM OUTDOOR TO INDOOR)
THICKNESS (t) mm (in)
CONDUCTIVITY (k) BTU-in °F-ft2-hr
RESISTANCE (R) ft2-°F-hr BTU
Outside Surface Resistance
-
-
0.250
EPDM Membrane
1.50 (0.059)
1.10
0.053
Rigid Insulation
100 (4.000)
0.20
20.000
Lightweight Concrete
50 (2.000)
3.70
0.540
Concrete Roof Slab
200 (8.000)
13.50
0.590
Inside Horizontal Surface Resistance
-
-
0.920
TOTAL RESISTANCE
22.353
Notes: a.) b.)
Values were obtained from ASHRAE Fundamentals 2001 (IP) Edition, Chapter 29 Table 22. The roof layer details are taken from Architectural drawings. Solving for Roof U - VALUE: Resistance
=
t/k
U - VALUE
=
1 / Total Resistance
U - VALUE
=
= 1 / 22.353
2
0.045 BTU / hr-ft -°F
Adding 20% for non ideal field condition: Total U-Value = 0.045 + (0.045 x 0.20) = 0.054 BTU / hr-ft2-°F
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SAES-N-004, Para. 4.4: “The overall heat transmission coefficient (U-factor) of insulated roofs, walls, partitions or floors shall not exceed 0.568 W/(m² °K) or (0.10 Btu/h ft² °F)”. Therefore, calculated Roof Ufactor of 0.054 Btu / hr-ft2-°F is within limit.
2.1.2
WALL OVERALL HEAT TRANSFER COEFFICIENT - "U" VALUE
MATERIAL CONSTRUCTION (FROM OUTDOOR TO INDOOR)
THICKNESS (t) mm (in)
CONDUCTIVITY (k) BTU-in °F-ft2-hr
RESISTANCE (R) ft2-°F-hr BTU
Outside Surface Resistance
-
-
0.250
CMU Wall
250 (10.000)
7.72
1.295
Batt Insulation
89 (3.500)
0.32
10.938
Gypsum Board
16 (0.630)
1.11
0.568
Inside Vertical Surface Resistance
-
-
0.680
TOTAL RESISTANCE
13.731
Notes: a.) b.)
Values were obtained from ASHRAE Fundamentals 2001 (IP) Edition, Chapter 29 Table 22. The wall layer details are taken from Architectural drawing. Solving for Wall U - VALUE: Resistance
=
t/k
U - VALUE
=
1 / Total Resistance
U - VALUE
=
= 1 / 13.731
2
0.073 BTU / hr-ft -°F
Adding 20% for non ideal field condition: Total U-Value = 0.073 + (0.073 x 0.20) = 0.088 BTU / hr-ft2-°F SAES-N-004, Para. 4.4: “The overall heat transmission coefficient (U-factor) of insulated roofs, walls, partitions or floors shall not exceed 0.568 W/(m² °K) or (0.10 Btu/h ft² °F)”. Therefore, calculated Wall U-factor of 0.088 Btu / hr-ft2-°F is within limit.
2.2 INTERNAL HEAT LOAD 2.2.1 LIGHTING HEAT LOAD GROUND FLOOR SI No.
Room Name
Room No.
Quantity
Lighting Fixtures,
Ballast Factor
Total Lighting
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1
Switchgear Room
-
2
Mechanical Room
-
3
Battery Room
-
watts
20%
Wattage watts
33
2 x 36
1.2
2851
1
2 x 36
1.2
96
8
2 x 36
1.2
691
1
2 x 36
1.2
96
4
2 x 36
1.2
346
1
2 x 36
1.2
96
Wattages/Unit
Total Watts
45032
45032
NOTE: The lighting wattages are taken from Electrical lighting layout drawings.
2.2.2 EQUIPMENT HEAT LOAD Zone No.
Room Name
Area, ft2
Quantity
1
Switchgear Room
See Tabulation 1
2
Mechanical Room
1
All
2500
2500
3
Battery Room
1
All
800
800
Tabulation 1 SI No.
Equipment Description
Tag No.
Qty
Wattages / Total Watts Unit
1
13.8 KV, 3-PHASE SWITCHGEAR
B57-SG-301
1
8515
8515
2
13.8 KV, 3-PHASE SWITCHGEAR
B57-SG-302
1
8515
8515
3
13.8 KV, 3-PHASE SWITCHGEAR
B57-SG-303
1
14300
14300
4
480V CONTROL GEAR
B57-MCC-001
1
3500
3500
5
480V CONTROL GEAR
B57-MCC-002
1
3500
3500
6
LOAD SHARING GEN. CONTROL PANEL
-
1
1200
1200
8
BATTERY CHARGER
B57-BC-001
1
656
656
9
BATTERY CHARGER
B57-BC-002
1
656
656
10
BATTERY DISCONNECT SWITCH
B57-SW-004
1
150
150
11
FIRE ALARM PANEL
B57-FACP-001
1
300
300
12
125VDC POWER PANEL
B57-DCPP-001
1
300
300
13
ANNUNCIATOR
B57-ANN-001
1
150
150
14
208/120 VAC POWER PANEL
B57-PP-001
1
120
120
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15
208/120 VAC POWER PANEL (HEATER PNL)
16
B57-PP-002
1
120
120
208/120 VAC MAIN DIST. PANEL
B57-MDP-001
1
500
500
17
45 KVA DRY TYPE TRANSFORMER
B57-XFR-002
1
1685
1685
18
LIGHTING PANEL
B57-LP-001
1
100
100
19
15 KVA DRY TYPE TRANSFORMER
B57-XFR-001
1
665
665
20
4-POLE MANUAL TRANSFER SWITCH
B57-MTS-001
1
100
100
TOTAL
45032
SWITCHGEAR HEAT DISSIPATION CALCULATION: 1) 13.8 KV, 3-PHASE SWITCHGEAR, B57-SG-301
Panel Number 101 102 103 104 105
Heat Loss in Watts Circuit Breaker Relaying & Qty. 1200 Amps Breaker Control 1 675 330 1 675 330 1 675 330 1 675 330 1 675 330
Vertical Bus 410 410 410 410 410
Cross Bus 288 288 288 288 288 TOTAL
Total Heat Loss (watts) 1703 1703 1703 1703 1703 8515
2) 13.8 KV, 3-PHASE SWITCHGEAR, B57-SG-302
Panel Number 101 102 103 104 105
Heat Loss in Watts Circuit Breaker Relaying & Qty. 1200 Amps Breaker Control 1 675 330 1 675 330 1 675 330 1 675 330 1 675 330
Vertical Bus 410 410 410 410 410
Cross Bus 288 288 288 288 288 TOTAL
Total Heat Loss (watts) 1703 1703 1703 1703 1703 8515
3) 13.8 KV, 3-PHASE SWITCHGEAR, B57-SG-303
Panel Number 101 102 103 104 105
Heat Loss in Watts Circuit Breaker Relaying & Qty. 1200 Amps Breaker Control 2 675 330 1 675 330 1 675 330 1 675 330 330
Vertical Bus 410 410 410 410 410
Cross Bus 288 288 288 288 288
Total Heat Loss (watts) 2378 1703 1703 1703 1028
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106 107 108
1 1 2
675 675 675
330 330 330
410 410 410
288 288 288 TOTAL
1703 1703 2379 14300
Note: See below reference for heat dissipation.
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2.3 RATES OF HEAT GAINS FROM OCCUPANTS The rates of heat gain from occupants of conditioned spaces are in accordance with ASHRAE Fundamentals Handbook, 2009 Edition Chapter 29 Table 1. The rates of heat gain for this facility used on the calculation are as follows: Type of Activity :
Seated, very light works
Sensible Heat Gain
:
250 Btu/Hr
Latent Heat Gain
:
200 Btu/Hr
2.4 NUMBER OF OCCUPANTS Zone No.
Room Name
Room No.
Area, ft²
Number of Occupants in Accordance with ASHRAE Layout Std. 62
Number of Occupants Used
1
Switchgear Room
-
2079
0
-
0
2
Mechanical Room
-
581
0
-
0
3
Battery Room
-
346
0
-
0
2.5 OUTDOOR AIR REQUIREMENTS
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a. The outdoor air requirement for ventilation is in accordance with ASHRAE Std. 62, Table 2. The number of occupants is accordance with architectural furniture layout. Zone No.
Room Name
Area, ft²
No. of Persons
Quantity
Outdoor Air Requirements, CFM
Outdoor Air Used, CFM
1
Switchgear Room
2079
0
2AC/Hr
1247
1247
2
Mechanical Room
581
0
Direct
100
100
3
Battery Room
346
0
Direct
606
606
TOTAL
1953
Since Switchgear Building is UNMANNED, No Outside Air Required due to Occupants. However, Outside Air shall be provided to Maintain Pressurization in order to prevent ingress of sand, fumes, dusts, etc.
b. In accordance with SAES-K-001, Section 4.4.11.2(a), the minimum amount of outside air shall equal the greater than 5% of supply air plus all exhaust air. Based on cooling load calculation: Total supply air
=
12,385 CFM
Exhaust air (CFM): Battery Room
=
606 CFM
Outside Air
=
(0.05 x 12,385) + 606
Outside Air
=
1,279 CFM
The ventilation air (1,279 CFM) as per SAES-K-001, Section 4.4.11.2(a) is less than the ventilation air from above Table (1,953 CFM), therefore 1,953 CFM outdoor air for ventilation will be used.
3.0 COOLING AND HEATING LOAD CALCULATION RESULTS 3.1
The designed cooling loads for the whole system are as follows: A) CALCULATION 1 (CONDITION-1) is in accordance with SAES-K-001, paragraph 4.2.1.4, cooling load calculated with the Summer Design Dry Bulb and Mean Coincident Wet Bulb temperatures at 2.5% exceedance. Total Cooling Load
:
342,016 Btu/hr
Sensible Cooling Load
:
342,016 Btu/hr
Supply Airflow
:
12,386 CFM
Outdoor Airflow
:
1,953 CFM
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Temperature Entering Dry Bulb
:
81.52 °F
Temperature Entering Wet Bulb
:
63.85 °F
Temperature Leaving Dry Bulb
:
56.00 °F
Temperature Leaving Wet Bulb
:
55.47 °F
Total Cooling Required with Outside Air
:
28.50 Tons
Total Heating Required with Outside Air
:
63,973 (18.7 kW
B) CALCULATION 2 (CONDITION-2) is in accordance with SAES-K-001, paragraph 4.2.1.5, cooling load calculated with the Summer Design Wet Bulb and Mean Coincident Wet Bulb temperatures at 2.5% exceedance. Total Cooling Load
:
322,936 Btu/hr
Sensible Cooling Load
:
297,558 Btu/hr
Supply Airflow
:
11,960 CFM
Outdoor Airflow
:
1,953 CFM
Temperature Entering Dry Bulb
:
78.80 °F
Temperature Entering Wet Bulb
:
64.46 °F
Temperature Leaving Dry Bulb
:
56.00 °F
Temperature Leaving Wet Bulb
:
55.47 °F
Total Cooling Required with Outside Air
:
27.29 Tons
Total Heating Required with Outside Air
:
63,973 (18.7 kW)
4.0 AIR CONDITIONING UNIT SELECTION The selection of air-cooled condensing units is in accordance with SAES-K-001, Section 4.2.1.7. The summer design dry bulb temperature at 1% exceedance and the following shall be used: a. The summer dry bulb temperature at 1% exceedance + 10 °F for facilities within Plant areas. b. The summer dry bulb temperature at 1% exceedance + 5 °F for facilities located in areas other than plant areas. Location
:
Summer Dry Bulb Temperature :
Shaybah (outside Plant areas) 117 °F + 5 °F = 122 °F
5.0 ELITE CALCULATION
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