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Varun Swarup
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Optimum Selection of Cooling Towers for Power Projects
Varun SwarupPaharpur Cooling Towers Ltd,
Kolkata
CII National Seminar on Capabilities, Opportunities and Challenges in
Boiler Turbine and Generator (BTG) Industry
India Habitat Centre, New Delhi25th September 2013
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What is a Cooling Tower ?
A cooling tower is a device for evaporative cooling of water by direct contact with air.
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Underlying PrinciplesRate of heat transfer in a cooling tower depends
on:Surface area of water in contact with airRelative velocity of air and water during the
contactDuration of air-water contact
Ambient wet bulb temperature is the limiting temperature to which water can be cooled.
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Classification of Cooling Towers
By method of providing air flow
Mechanical draught (usually induced
draught)
Natural draught
By air-water relationship
Counterflow
Crossflow
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Mechanical Draught Counterflow Tower
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Mechanical Draught Crossflow Tower
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Natural Draught Tower
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More ChoicesType of Fill
Splash type Film type
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More ChoicesStructure Material
WoodFRPRCC
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Drift EliminatorsRemove entrained water from the discharge
air stream.
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Air Movement PackageMotorDriveshaftGearboxFanFan stack
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Some Statistics
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Large Industrial TowersFlow Type
1961-1970 1971-1980 1981-1990 1991-2000 2001-20100%
10%20%30%40%50%60%70%80%90%
100%
242 571 1,083 1,246
1,566
56 20
168 604
3,208
Crossflow Counterflow
Year
% o
f C
ell
s S
old
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Large Industrial Towers Structural Material
1961-1970 1971-1980 1981-1990 1991-2000 2001-20100
1,000
2,000
3,000
4,000
5,000
6,000
176 335 836 1,161
3,776
122 256415
689
811
187
RCC Wood FRP
Year
No. of
Cell
s S
old
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Large Industrial Towers Fill Type
1961-1970 1971-1980 1981-1990 1991-2000 2001-20100
1,000
2,000
3,000
4,000
5,000
6,000
298 591 1,083 1,391
2,758 168 455
1,975
4
40 1
Splash Film Fill-less Hybrid
Year
No. of
Cell
s S
old
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Large Industrial Towers Fill Material
1961-1970 1971-1980 1981-1990 1991-2000 2001-2010
Wood 230 381 192 47 29
Plastic 0 44 773 1665 4652
RCC 56 113 286 134 53
ACB 12 53 0 0 0
500
1,500
2,500
3,500
4,500
Wood Plastic RCC ACB
No. of
Cell
s S
old
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Large Industrial TowersInstalled in Power Plants
Note: These figures do not include smaller cooling towers serving diesel generating sets and small captive power plants.
1961-1970
1971-1980
1981-1990
1991-2000
2001-2010
0
20,000
40,000
60,000
80,000
100,000
120,000
1,865 4,08514,725 15,555
70,487
Cumulative 106,717
Year
Pow
er
Pla
nt
Cap
acit
y(M
W)
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Thermal Design Parameters
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Design ParametersWater Flow RateHot Water TemperatureCold Water TemperatureWet Bulb Temperature
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Effect of Varying Design Parameters on
Cooling Duty
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Water Flow Rate
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Range (∆T)
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Approach
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Wet Bulb Temperature
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SummaryCooling tower is limited only by the wet bulb
temperatureChoice of mechanical draught vs. natural draughtChoice of counterflow vs. crossflowChoice of film-type vs. splash-type fillChoice of structure materialDrift is NOT a lossFan weight does NOT affect power consumptionVarying thermal design parameters affects tower
sizing in different ways
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Thank You
Paharpur Cooling Towers LtdPaharpur House, 8/1/B Diamond Harbour Road, Kolkata – 700 027, INDIA
Ph: +91-33-4013 3000 Fax: +91-33-4013 3499 E-mail: [email protected]
