air flow calculation

PEA Modular Substation PROJECT

3354/8-9 Manorom Bldg., 3rd Fl., Rama 4 Rd., Klongton, Klongtoey, Bangkok Thailand Tel : 02 685 8600 Fax 02 685 8699 GRID

PEA Contract No. : -------------- Modular Substation

Group A Substation :Chiang Mai 5, Phitsanulok 6 , Nakhon Sawan 4

Customer : LOXLEY PUBLIC COMPANY LIMITED

Equipment : MOBILE OFFICE Module “D”

Subject : Air Flow Calculation Rev.1

Air Flow Calculation3354/8-9 Manorom Bldg., 3rd Fl., Rama 4 Rd., Klongton, Klongtoey, Bangkok Thailand Tel : 02 685 8600 Fax 02 685 8699 GRID

For Approval

11 KV SWITCHGEAR (S18B1) FOR CCG HDS PROJECT PANEL A6 & B8

SUMMARY OF COOLING LOAD CALCULATION CUSTOMER INFO : ALSTOMPROJECT INFO : MODULE C -22KV SWITCHGEAR BUILDING

Item Heat Gain (BTU/h) Exterior wall 1 (north) ---Exterior wall 2 (East) 400.12Exterior wall 3 (South) 175.8Exterior wall 4 (West) 400.12From Partition 240.6

From Ceiling 526.29 From Floor 344.11

From People 1000From Lights 807.84From Motor 140From Appliance (22 kv Switchgear and LB)

12022.4 at 100% load factorFrom Misc Sources ---Room Heat Gain Total 16,057.28

BTU/HFrom Ventilation 836.2From Infiltration 974.58 Appalatus Load Total 1,810.78

BTU/H GRAND TOTAL HEAT GAIN = 17,868.06

BTU/HTON OF REFRIGELATION = 17,868.06/12000 =

1.489 TON SELECT AIR CONDITION SPLIT TYPE 18000 BTU/H

or 1.5 Ton Refrigeration SUMMARY OF INDUCED DRAUGHT VENTILATION FOR TRANSFORMER ROOM

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Select Fan Diameter 8 inch (Dia 20.32 cm) 3 sets ( Operate 2 sets per once). Use Timer switch to control two steps,First Step: First Fan (Left) or Third fan (Right) will be alternately operated in every 12 hrs.Second Step: if the temperature room reach to 40°C, Second Fan (Center) will be operated Select Incoming air cross section under floor = 30 x 30 sq.cm. = 900 sq.cm with filter and screen guard under floorSelect Incoming air cross section pass transformer 50 kVA = 2820 sq.cm with screen and guard block out under transformer

1.HEAT GAIN Calculation

1.1 DATA FOR CALCULATION

- 22 KV SWITCHGEAR CONTAINER See Drawing no. PEA-MDL-AG-L-001 SHEET 1 AND 2, PEA- MDL-AG- L-002 SHEET 1 ,C&t-1149-01-001 SHEET 1 Dimension of container W X L x H = 3400 x 9000 x 3200 mm. 1 m = 3.2809 ft

Or W x L x H = 11.155 X 29.528 X 10.498 feet Dimension of only switchgear container W X L x H = 3400 x 7000 x 3200 mm. 1m = 3.2809 ft

Or - Section for cooling load calculation W x L x H = 11.155 X 22.966 X 10.498 ft is for cool 22 kv six switchgear and one load break switch volume =2689.437 cu.ft- Section for Induced Draght Ventilation W X L x H = 3400 x 2000 x 3200 mm. 1m = 3.2809 ft Or W X L X H = 11.155 X 6.562 X 10.498 ft volume = 768.444 cu.ft Is for air ventilation one 50 KVA transformerTemperature data from typical design from LA CROSSE WISCONSIN 9 as attachment

- SUMME INSIDE F - DIFFER.

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R OUTSIDE F

ENCE

- DRY BULB

- 95 - 78 - 17

- WET POINT

- 76 - 65 - 11

- - -

- Over all Heat Transfer Coefficient U = 1/R Btu per hr sq.ft F

- Resistance to heat flow R = 1/U = 1/f1 +x1/k1+ x2/k2+ x3/k3+ 1/f2) 1/ Btu per hr sq.ft F

- f1 = Coefficient of Surface Conductance inside air film = 1.46 Btu per hr sq ft F

- f2 = Coefficient of Surface Conductance outside air film = 6 Btu per hr sq ft F

air still =1.46-1.63 air move 7.5 mile/h = 4 air move at 15 mile/h =6

- x1 = thickness of metal Material for uniform material = 1/8 inch

- x2 = thickness of polyurethane Material for uniform material = 2 inch

- x3 = thickness of metal Material for uniform material = 1/8 inch

- K1 =thermal conductivity of metal = infinity Btu in. per hr sq ft per degree F

- K2 =thermal conductivity of polyurethane = 0.17 Btu in. per hr sq ft per degree F

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- K3 =thermal conductivity of metal = infinity Btu in. per hr sq ft per degree F

- R = 1/U = 1/f1 +x1/k1+ x2/k2+ x3/k3+ 1/f2) 1/ Btu per hr sq.ft F

- = 1/1.46 +1/8 /infinity +2/0.17 +1/8 /infinity + 1/6

- = 0.6849 + 0 + 11.76 + 0 + 0.166

Resistance to heat flow (R) = 12.62

Over all Heat Transfer Coefficient (U) = 1/R = 1/12.62 = 0.079 BTU/hr sq.ft. F see Ref Refrigeration and air condition table 10.5 correction factor for solar radiation

Allowance for Solar Radiation (F)Type of surfaces East

wallSouth Wall

West wall

Flat roof

Dark-colored surfaces such asSlate RoofingTar RoofingBlack Plaints

8 5 8 20

Medium-colored surfaces such asUnpainted woodBrickRed tileDark cementRed gray or green paint

6 4 6 15

Light-colored surfaces such asWhite stoneLight-Colored cementWhite paint

4 2 4 9

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1.2 STEP FOR HEAT GAIN CALCULATION Assume Transformer room temperature = 104°F Switchgear room temperature = 78°C Outdoor temperature = 95°C

1.2.1 Heat Gain through Exterior Walls of Transformer Room Q = A x U x TD A = Exterior wall Area (North) = N/A U = Over all heat transfer coefficient = N/A Btu per hr Sq.ft F TD = Difference in temperature between the air on the two sides of the wall or roof = Transformer room 104 F -Switchgear room 78 F = N/A Q = N/A [ Heat Gain of Transformer Room is not Calculated in Switch Gear Room Part ]

1.2.2 Heat Gain through Exterior Walls Q = A x U x (TD + Correction factor of solar Radiation) A = Exterior wall Area (East) = 7 m x 3.2 m = 22.97 x 10.5 ft = 241.185 sq.ft U = Over all heat transfer coefficient = 0.079 Btu per hr. Sq.ft F TD = Difference in temperature between the air on the two sides of the wall or roof = Outside 95 F -Switchgear room 78 F = 17 F Q = 241.185 x 0.079 x ((95-78)+ 4) Q = 400.12 BTU/H

1.2.3 Heat Gain through Exterior Walls Q = A x U x (TD + Correction factor of solar Radiation) Correction factor of solar Radiation see table 10.5 A = Exterior wall Area (South) = 3.4 m x 3.2 m = 11.155 x 10.5 ft = 117.128 sq.ft

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U = Over all heat transfer coefficient = 0.079 Btu per hr Sq.ft F TD = Difference in temperature between the air on the two sides of the wall or roof = Outside 95 F -Switchgear room 78 F = 17 F Q = 117.128 x 0.079 x ((95-78)+ 2) Q = 175.8 BTU/H1.2.4 Heat Gain through Exterior Walls Q = A x U x ( TD + Correction factor of solar Radiation) Correction factor of solar Radiation see table 10.5 A = Exterior wall Area (west) = 7 m x 3.2 m = 22.97 x 10.5 ft = 241.185 sq.ft U = Over all heat transfer coefficient = 0.079 Btu per Hr Sq.ft F TD = Difference in temperature between the air on the two sides of the wall or roof = Outside 95 F -Switchgear room 78 F = 17 F Q = 241.185 x 0.079 x ((95-78)+ 4) Q = 400.12 BTU/H1.2.5 Heat Gain through Partition Walls Q = A x U x TD A = Partition wall Area (North) = 3.4 m x 3.2 m = 11.155 x 10.5 ft = 117.128 sq.ft U = Over all heat transfer coefficient = 0.079 Btu per hr. Sq.ft F TD = Difference in temperature between the air on the two sides of the wall or roof = Transformer room 104 F -Switchgear room 78 F = 26 F Q = 117.128 x 0.079 x 26 Q = 240.6 BTU/H

1.2.6 Heat Gain through Ceiling Walls Q = A x U x ( TD + Correction factor of solar Radiation)

A = Ceailing wall Area = 7 m x 3.4 m = 22.97 x 11.155 ft = 256.23 sq.ft

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U = Over all heat transfer coefficient = 0.079 Btu per hr Sq.ft F TD = Difference in temperature between the air on the two sides of the wall or roof = Outside 95 F -Switchgear room 78 F = 17 F Correction factor of solar radiation on ceiling walls = 9 [Table 10.5] Q = 256.23 x 0.079 x (17+9) Q = 526.29 BTU/H

1.2.7 Heat Gain through Floor Walls Q = A x U x TD A = Ceiling wall Area = 7 m x 3.4 m = 22.97 x 11.155 ft = 256.23 sq.ft U = Over all heat transfer coefficient = 0.079 Btu per Hr Sq.ft F TD = Difference in temperature between the air on the two sides of the wall or roof = Outside 95 F -Switchgear room 78 F = 17 F Q = 256.23 x 0.079 x 17 Q = 344.11 BTU/H

1.2.8 Heat Gain From People (Occupanted) see ref Trane air conditioning manual Table 3-14 Sensible Heat Gain QS = No. of People x Sensible Heat Value Latent Heat Gain QL = No. of People x Latent Heat Value For Laboratory Sensible Heat value = 330 BTU/h table 3-14 For Laboratory Latent Heat value = 670 BTU/h Total Heat Gain = Qs + QL = 330 + 670 = 1000 BTU/h

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1.2.9 Heat Gain From Light Q = Total Watt of Fluorescent Lights x 3.4 x allowance factor 12 Lamps open for service day ,normal open lamp less than 6 Lamps Ballast Electronic allowance factor = 1.1 as หนั�งสื�อการลดค่�าใช้�จ่�ายพล�งงานั หนั�า 120 Conventional Ballast allowance factor = 1.2 as หนั�งสื�อการลดค่�าใช้�จ่�ายพล�งงานั หนั�า 121 Q = 6 x 36 w x 3.4 x 1.1 = 807.84 BTU/H

1.2.10 Heat Gain From Appliance (22 kv Switchgear and Load Break and bus bar ) See Ref Data Power loss from manufacturer Q =( Total Watt loss of switchgear + watt loss of Load Break Sw. + Busbar loss )x 3.414 Total watt loss of Switchgear = ( 1 x 553 ) + (5 x 469) = 2898 W Watt loss of load Break SW = 1 x 150 w = 150W Busbar loss =3 x I2 x rho x L/A I = Current pass Bus bar about 1250 A [ Average Bus bar Current ] Rho = Resistivity of copper = 0.01785 ohm. Sq.mm² /m [ Ref.ABB manual 10th Table1-15 Page32 ] L = Length of Busbar in meter = 3.290+1.250 = 4.540 m. A = Cross section of Busbar = 800 sq.mm Bus bar loss = 3 x 1250 x 1250 x 0.01785 x 4.54 / 800 = 473.5 w Q = ( 2898 +150 + 473.5) x 3.414 Q = 12022.4 BTU/H

1.2.11 Heat Gain From Motor

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See Ref Trane Air conditioning Manual table 3-16 Heat Gain From Electric motor

NAMEPLATE RATING, HP

APPROXIMATE EFFICIENCY

HEAT GAIN BTUH PER HPFOR CONTINUOUS RUN

Up to ¼ 60 4200½ to 1 70 3600

1 ½ to 5 80 32007 ½ to 20 85 3000OVER 20 88 2900

Q = Nameplate motor x heat gain btu/hp In switchgear building have one up to 1/30 hp fan motor select 4200 Q = 1/30 x 4200 Q = 140 BTU/H 1.2.12 Heat Gain for Ventilation air /Infiltration 1.2.12.1 Heat Gain for Ventilation air See Ref Trane air conditioning manual table 3-22 recommends 20 cfm per Occupant for a Laboratories The outdoor air must be reduced to the design temperature . This represents a load on the air conditioning equipment Sensible heat QS = 1.08 Q (To - Ti ) Q = Total of Occupants in cfm. To = Outside temperature = 95 F Ti = Inside temperature Room = 78 F

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Qs = 1.08 x 20 x (95-78) = 367.2 BTU/H Latent Heat QL = 0.7 Q ( HRO – HRI) Humidity of outside air HRO at 95F DB and 76 F WB = 105 grains/lb Humidity of inside air HRi at 78 F DB and 65 F WB = 71.5 grains/lb QL = 0.7 x 20 x (105-71.5) = 469 BTU/H

Total Heat Gain = Qs +QL = 367.2 + 469 = 836.2 BTU/H

1.2.12.2 Heat Gain for Infiltration See Ref Trane air conditioning manual Table 3-21 INFILTRATION THROUGH WINDOWS (CFH/ft)

Type of window

Description of window Wind Velocity, MPH7 1/2 15

Metal Sash

Non-weather stripped Locked

33 70

Non-weather stripped UnLocked

34 74

Weather stripped UnLocked

13 32

See Drawing No. as item 1.1 Parameter of each window = (2.4 x 2) +(2.4 x 2) +(2.4 x 2) +(2.4 x 2)+(2.4 x2)+(1.6 x 2) +(2 x 2)+(0.8 x 2) in meter = 32.8 meter = 32.8 x 3.2809 = 107.6 lin ft

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Flow rate = 13 x 107.6 = CFH or 1398.8/60 = 23.31 CFM Sensible heat QS = 1.08 Q (To - Ti ) Q = Total of Occupants in CFM To = Outside temperature = 95 F Ti = Inside temperature Room = 78 F Qs = 1.08 x 23.31 x (95-78) = 427.97 BTU/H Latent Heat QL = 0.7 Q ( HRO – HRI) Humidity of outside air HRO at 95F DB and 76 F WB = 105 grains/lb Humidity of inside air HRi at 78 F DB and 65 F WB = 71.5 grains/lb QL = 0.7 x 23.31 x (105-71.5) = 546.6 BTU/H

Total Heat Gain = QH +QL = 427.97 + 546.6 = 974.58 BTU/H

2.3 FAN FOR SWITCHGEAR AND TRANSFORMER ROOMS As E.I.T

For the cooling air requirement of the transformer rated 50 KVA Service Transformer Power dissipation Pv = no load loss + Load Loss at 75 celcius see Ref Data power loss from manufacturer as annex 2 data = 125 + 775 watt

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Pv = 900 wattVentilation Fan Define Incoming air cross section > 0.001 sq.m x KVA of Transformer and more than 0.05 sq.m

0.001 x 50 > 0.05 sq.m > 500 sq.cm

Exhaust air must installed fan and ventilate air out more than 8.40 cu.m/min .kwloss at full load As Standard of EIT 2001-51 item 6.4.12.3.1 and item 6.4.12.3.2 CFAN > 8.40 x KW LOSS CU.M / MIN 1 m= 3.2809 ft CFAN > 35.316 x 8.40 x KW LOSS CFM CFAN > 296.65 x KWLOSS CFM

KWLOSS Full Load Loss of 50 KVA Transformer = 0.9 KW CFAN > 296.66 x 0.9 CFM

267 CFM

REFERENCE

1. มาตรฐานัระบบปร�บอากาศ และระบายอากาศ มาตรฐานั ว.สื. ท 3003-40 ม นัาค่ม 2547

2. การออกแบบและต!ดต�"งระบบไฟฟ%า ตามมาตรฐานัของการไฟฟ%า อาจ่ารย'ล�อช้�ย ทองนั!ล

3. TRANE AIR CONDITIONING MANUAL LA CROSSE WISCONSIN 1965

4. ABB MANUAL 11 EDITION PAGE 159-169

5. การท(าค่วามเย*นั และการปร�บอากาศ ผศ. ช้,ช้�ย ต. ศ!ร!ว�ฒนัา 10th Edition 2549

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6 มาตรฐานั การต!ดต�"งไฟฟ%าสื(าหร�บประเทศไทย ฉบ�บปร�งปร/งค่ร�"งท 0 1 พ.ศ. 2551

ADDITIONAL REFERENCE

1. ABB SWITCHGEAR MANUAL 9TH EDITION PAGE 154 2. ENERGY EFFICIENCY GUIDE FOR INDUSTRY IN ASIA PAGE23. TRANE AIR CONDITIONING MANUAL LA CROSSE WISCONSIN PAGE

49

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ABB SWITCHGEAR MANUAL 9TH EDITION PAGE 154

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ENERGY EFFICIENCY GUIDE FOR INDUSTRY IN ASIA PAGE2

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TRANE AIR CONDITIONING MANUAL LA CROSSE WISCONSIN

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FAN CONTRAINER LOGIC CONTROL DIAGRAM

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air flow calculation

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