Hvac Calculation

SAUDI ARAMCO SAUDI ARAMCO

HVAC CALCULATIONSHVAC CALCULATIONS

FORFOR

SWITCHGEAR BUILDING – SABKHA 113SWITCHGEAR BUILDING – SABKHA 113

SHAYBAHSHAYBAH

PREPARED BY:PREPARED BY:

GULF CO-OPERATION SYMBOLS CONT. CO. LTDGULF CO-OPERATION SYMBOLS CONT. CO. LTD

AL-KHOBAR, SAUDI ARABIAAL-KHOBAR, SAUDI ARABIA

OCTOBER 2012OCTOBER 2012

D 12 October 2012 Issued for 100% Review

REV DATE STATUSWRITTEN BY

(Name)CHECKED BY

(Name)APPROV./AUTHOR. BY

(Name)

DOCUMENT REVISIONS

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PETROCON ARABIA LIMITED

TABLE OF CONTENTS

ITEM NO. TITLE PAGE

1.0 HVAC DESIGN DATA......................................................................................................................3

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

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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

INSIDE DESIGN CONDITIONS

Room NameTemperature

OFRelative 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)

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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

Adding 20% for non ideal field condition:

Total U-Value = 0.045 + (0.045 x 0.20)

= 0.054 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

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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 LOADGROUND FLOOR

SI No. Room NameRoom

No.Quantity

Lighting Fixtures,

watts

Ballast Factor 20%

Total Lighting 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.

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2.2.2 EQUIPMENT HEAT LOAD

Zone No.

Room Name Area, ft2 Quantity Wattages/UnitTotal 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. QtyWattages /

UnitTotal Watts

1 13.8 KV, 3-PHASE SWITCHGEAR B57-SG-301 1 8515 8515



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

15208/120 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:

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1) 13.8 KV, 3-PHASE SWITCHGEAR, B57-SG-301

Heat Loss in Watts

Panel NumberCircuit Breaker Relaying &

ControlVertical

BusCross Bus

Total Heat Loss (watts)Qty. 1200 Amps Breaker

101 1 675 330 410 288 1703102 1 675 330 410 288 1703103 1 675 330 410 288 1703104 1 675 330 410 288 1703105 1 675 330 410 288 1703

TOTAL 8515


Heat Loss in Watts


ControlVertical

BusCross Bus


101 1 675 330 410 288 1703102 1 675 330 410 288 1703103 1 675 330 410 288 1703104 1 675 330 410 288 1703105 1 675 330 410 288 1703

TOTAL 8515


Heat Loss in Watts


ControlVertical

BusCross Bus


101 2 675 330 410 288 2378102 1 675 330 410 288 1703103 1 675 330 410 288 1703104 1 675 330 410 288 1703105 - - 330 410 288 1028106 1 675 330 410 288 1703107 1 675 330 410 288 1703108 2 675 330 410 288 2379

TOTAL 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 NameRoom

No.Area,

ft²

Number of Occupants in Accordance with

Number of Occupants

UsedLayoutASHRAE Std. 62

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 NameArea,

ft²No. 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

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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

5.0 ELITE CALCULATION

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