SAUDI ARAMCO
SAUDI ARAMCO
HVAC CALCULATIONS
HVAC CALCULATIONS
FOR
FOR
SWITCHGEAR BUILDING – SABKHA 113
SWITCHGEAR BUILDING – SABKHA 113
SHAYBAH
SHAYBAH
PREPARED BY:
PREPARED BY:
GULF CO-OPERATION SYMBOLS CONT. CO. LTD
GULF CO-OPERATION SYMBOLS CONT. CO. LTD
AL-KHOBAR, SAUDI ARABIA
AL-KHOBAR, SAUDI ARABIA
OCTOBER 2012
OCTOBER 2012
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 DB OF 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
Room Name TemperatureOF 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.) Values were obtained from ASHRAE Fundamentals 2001 (IP) Edition, Chapter 29 Table 22. b.) The roof layer details are taken from Architectural drawings.
Solving for Roof U - VALUE: Resistance = t / k
U - VALUE = 1 / Total Resistance = 1 / 22.353 U - VALUE = 0.045 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 Roof U-factor 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.) Values were obtained from ASHRAE Fundamentals 2001 (IP) Edition, Chapter 29 Table 22. b.) The wall layer details are taken from Architectural drawing.
Solving for Wall U - VALUE: Resistance = t / k
U - VALUE = 1 / Total Resistance = 1 / 13.731 U - VALUE = 0.073 BTU / hr-ft2-°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
watts 20% Wattage watts 1 Switchgear Room - 33 2 x 36 1.2 2851 1 2 x 36 1.2 96 2 Mechanical Room - 8 2 x 36 1.2 691 1 2 x 36 1.2 96 3 Battery Room - 4 2 x 36 1.2 346 1 2 x 36 1.2 96
NOTE: The lighting wattages are taken from Electrical lighting layout drawings.
2.2.2 EQUIPMENT HEAT LOAD Zone
No. Room Name Area, ft2 Quantity Wattages/Unit
Total Watts 1 Switchgear Room See Tabulation 1 45032 45032 2 Mechanical Room 1 All 2500 2500 3 Battery Room 1 All 800 800
Tabulation 1 SI
No. Equipment Description Tag No. Qty
Wattages /
Unit Total Watts 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
15 208/120 VAC POWER PANEL (HEATER
PNL) B57-PP-002 1 120 120 16 208/120 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
Heat Loss in Watts Panel Number Circuit Breaker Relaying &
Control
Vertical
Bus Cross Bus
Total Heat Loss (watts) Qty. 1200 Amps Breaker
101 1 675 330 410 288 1703 102 1 675 330 410 288 1703 103 1 675 330 410 288 1703 104 1 675 330 410 288 1703 105 1 675 330 410 288 1703 TOTAL 8515 2) 13.8 KV, 3-PHASE SWITCHGEAR, B57-SG-302
Heat Loss in Watts Panel Number Circuit Breaker Relaying &
Control
Vertical
Bus Cross Bus
Total Heat Loss (watts) Qty. 1200 Amps Breaker
101 1 675 330 410 288 1703 102 1 675 330 410 288 1703 103 1 675 330 410 288 1703 104 1 675 330 410 288 1703 105 1 675 330 410 288 1703 TOTAL 8515 3) 13.8 KV, 3-PHASE SWITCHGEAR, B57-SG-303
Heat Loss in Watts Panel Number Circuit Breaker Relaying &
Control
Vertical
Bus Cross Bus
Total Heat Loss (watts) Qty. 1200 Amps Breaker
101 2 675 330 410 288 2378 102 1 675 330 410 288 1703 103 1 675 330 410 288 1703 104 1 675 330 410 288 1703 105 - - 330 410 288 1028
106 1 675 330 410 288 1703 107 1 675 330 410 288 1703 108 2 675 330 410 288 2379 TOTAL 14300 Note: See below reference for heat dissipation.
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 Occupants Number of Used Layout ASHRAE Std. 62 1 Switchgear Room - 2079 0 - 0 2 Mechanical Room - 581 0 - 0 3 Battery Room - 346 0 - 0
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
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 : Shaybah (outside Plant areas) Summer Dry Bulb Temperature : 117 °F + 5 °F = 122 °F
