The document discusses cooling tower performance assessment and testing. It explains that cooling towers play a vital role in dissipating waste heat from power plants. Performance decreases over time due to factors like fill clogging, deposition, algae growth, and equipment damage. The document outlines parameters to measure during testing like temperatures, flows, fan power. It provides details on testing procedures, analyzing results, and improving performance through cleaning, maintenance and optimizing air flow and water distribution.

1. Cooling Tower
g
Performance Assessment
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2. Cooling Tower Thermal Performance
Importance of Cooling Tower Performance
Testing
Cooling water system plays a vital role in
po a ce o oo g o o
Monitoring
Cooling water system plays a vital role in
dissipation of waste heat in power station.
More than 60 % of total heat input to the
p
plant is finally dissipated as waste heat. The
waste heat from the power plant is carried
away by circulating water and ultimately gets
dissipated in cooling tower.
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3. CenPEEP
Importance of Cooling Tower Performance
Monitoring
3
y The efficiency of cooling tower has direct effect on
condenser vacuum and in turn, the heat rate of the
station
station.
y 1oC rise in cold water temperature corresponds to
y 1oC rise in cold water temperature corresponds to
2.5mm vacuum loss or 5 kcal/kWh in HR which
corresponds to approx. Rs. 68 lakhs of loss per
p pp p
annum in terms of direct fuel cost for a 500 MW
unit.
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4. Cooling Tower Thermal Performance
Parameters to be Measured
g
Testing
Parameters to be Measured
• Wet Bulb Temperature (WBT) at Tower inlet
• Cold Water Temperature
• Hot Water Temperature
• CW Flow to each Tower
• Fan Motor Power
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5. Cooling Tower Thermal Performance Testing
Acceptable Test Conditions
Cooling Tower Thermal Performance Testing
• CW Flow rate : 90 – 110% of Design
• Cooling Range : 80 – 120% of Design
• Wet-Bulb Temp : Design +/- 8.50 C
• Fan Motor Power : 90 – 110% of Design
• Average wind velocity : < 4.5 m/s
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6. Cooling Tower Performance
Salient Terms Used in CT Testing
A h
Approach
Difference between the Cold Water Temperature
Difference between the Cold Water Temperature
at CT outlet and Inlet air Wet Bulb Temperature
Range
Difference between the Hot Water Temperature
(inlet to CT) and Cold Water Temperature (outlet
of CT)
of CT)
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7. Cooling Tower Performance
Salient Terms Used in CT Testing
T C bilit
g
Tower Capability
¾ The most reliable means to assess the cooling
¾ The most reliable means to assess the cooling
tower thermal performance.
¾ It is defined as the percentage of water that
the tower can cool to the design cold water
temperature when the inlet wet-bulb, cooling
range, water flow rate and fan motor power are
all at their design value
all at their design value.
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8. Cooling Tower Performance
Tower Capability
g
Tower Capability in Percentage = Adjusted Test Flow Rate
Predicted Water Flow Rate
Adjusted Test = Measured flow x { Design KW of fans}0.333
Flow Rate { Test KW of Fans }
Predicted Water Flow Rate =Calculated from Manufacturer
graphs and actual test conditions
g p
i.e. WBT, Range and Cold water
temperature.
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9. Cooling Tower Thermal Performance Testing
Tower Capability = { QT } * { CellD } * { PD }.333
* 100
{ Q } { C } { }
{ Qpred } { CellT } { PT }
Where :
QT = Measured water flow rate, t/hr
Qpred = Predicted water flow rate, t/hr
CellD = No. of cells for design water flow rate
CellT = No. of cells in operation during test
PD = Fan motor power design, kW
D p g
PT = Fan motor power measured, kW
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10. Cooling Tower Performance
Performance Analysis
g
• CT degradation to be assessed based on
Capability test
Capability test
• Deviation to be derived from actual
temperature and predicted cold water
temperature
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11. CenPEEP
Causes for Performance Deterioration
y Fill clogging
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¾ Increase in weight of 2-3 times
y Deposition in the fills comes from
¾ the turbidity of make up water
¾ air borne dust from the atmospheric air being
drawn into the cooling tower
g
¾ precipitates of dissolved silica
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12. CenPEEP
Causes for Performance Deterioration
y Damage of fills.
y Chocking of nozzle
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y Chocking of nozzle.
y Falling of nozzle.
y Damage of splash bars
y Damage of splash bars.
y Algae formation on splash bars
y Damaged drift eliminators
g
y Unequal water flow in different cells.
y Recirculation of vapors.
y Poor air flow due to less blade angle.
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13. CenPEEP
Causes for Performance Deterioration
y Hot water distribution pipe damage
y Annular clearance between distribution pipe
13
Annular clearance between distribution pipe
and hot water channel
y Growth of trees/plants/bushes near cooling
tower
y Overflow of cold water basin.
li f
y Improper quality of water
¾ Control of COC
¾ Control of Turbidity
¾ Control of Turbidity
y Rain/any other water entering in open
channel
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14. CenPEEP
Optimizing Cooling Tower Performance
y Maintaining proper L/G ratio
¾ Equal water distribution between the cells
14
¾ Equal water distribution between the cells
¾ Visual inspection of pipes, nozzles, fills, etc., for
proper water distribution.
y Increasing the air flow
¾ By increasing blade angle to obtain max allowable
loading of fans
loading of fans
Ù By plugging all air path that do not pass through the fill
zone
i Sealing shaft hole of fan
i Sealing shaft hole of fan.
ii Sealing door openings of fan chamber.
iii Sealing the fan hub area.
iv Maintaining blade tip clearances
iv Maintaining blade tip clearances
v Reducing drift handled by fan
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15. CenPEEP
Optimizing Cooling Tower Performance
y Cleaning of fills with water jets
l f f ll ll b f
15
y Cleaning of fills manually by removing from tower
y Cleaning of cold water basin during overhauls.
y Regular cleaning/checking of nozzles.
y Continuous Chlorination & Shock dozing to
i t i i d FRC
maintain required FRC
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16. 16
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17. Cooling Tower Thermal Performance Testing
Location Of Inlet Wet Bulb Temperature for Station with Counter Flow Tower
g f g
L L
“L” < 2 Meters, “X” Measurement Station.
,
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18. Cooling Tower Thermal Performance Testing
Location Of Inlet Wet Bulb Temperature for Station with Cross Flow Tower
g f g
L
L
“L” < 2 Meters, “X” Measurement Station.
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19. lb
Cooling Tower Thermal Performance Testing
Wet Bulb Temp. measurement setup
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20. Grid setup for Cold Water Temp. measurement
Cooling Tower Thermal Performance Testing
p f p
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21. Cooling Tower Thermal Performance Testing
Grid setup for Cold Water Temp. measurement of single cell
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22. Cooling Tower Thermal Performance Testing
Grid setup for Cold Water Temp. measurement of single cell
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23. CenPEEP
Grid Measurement for Cold Water Temperature for one Cell
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Grid of 48 probes
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24. CT Performance Test
Design Cell -14 Cell - 11 Total Tower
CWT 32 31 33 31 84 31 6
CWT 32 31.33 31.84 31.6
HWT 44 40.51 41.13 41.1
WBT 27 7 24 52 24 42 24 6
24
WBT 27.7 24.52 24.42 24.6
CW Flow 2222/40000 2520 2515 44188
Fan Power
(A )
47.81 45.65 43.84 44.17
(Average)
Range 12 9.18 9.29 9.50
Approach 4.3 6.81 7.42 7.0
Effectiveness
(Actual)
73.62 57.4 55.59 57.58
Effectiveness 63.22 64.4 64.32
(EXP)
Capability 100 87.13 80.04 85.07
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25. CenPEEP
Cooling Tower Thermal Performance Testing
90% Flow; Cold Water vs. Wet Bulb
25
32 0
33.0
34.0
35.0
36.0
37.0
WATER
ATURE
C
27.0
28.0
29.0
30.0
31.0
32.0
23.0 24.0 25.0 26.0 27.0 28.0 29.0 30.0 31.0 32.0 33.0
COLD
W
TEMPERA
Wet Bulb (C)
C-8.8C B-11.0C A- 13.25C
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26. CenPEEP
Cooling Tower Thermal Performance Testing
100% Flow; Cold Water vs. Wet Bulb
26
33.0
34.0
35.0
36.0
37.0
WATER
ATURE
C
28.0
29.0
30.0
31.0
32.0
23 0 24 0 25 0 26 0 27 0 28 0 29 0 30 0 31 0 32 0 33 0
COLD
W
TEMPERA
23.0 24.0 25.0 26.0 27.0 28.0 29.0 30.0 31.0 32.0 33.0
Wet Bulb (C)
C-8.8C B-11.0C A- 13.25C
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27. CenPEEP
Cooling Tower Thermal Performance Testing
110 % Flow; Cold Water vs. Wet Bulb
27
33.0
34.0
35.0
36.0
37.0
WATER
ATURE
C
28.0
29.0
30.0
31.0
32.0
23 0 24 0 25 0 26 0 27 0 28 0 29 0 30 0 31 0 32 0 33 0
COLD
W
TEMPERA
23.0 24.0 25.0 26.0 27.0 28.0 29.0 30.0 31.0 32.0 33.0
Wet Bulb (C)
C-8.8C B-11.0C A- 13.25C
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28. CenPEEP
Cooling Tower Thermal Performance Testing
28
90% Flow; Cold Water vs. Wet Bulb
31 0
32.0
33.0
34.0
35.0
36.0
37.0
WATER
RATURE
C
27.0
28.0
29.0
30.0
31.0
32.0
23.0 24.0 25.0 26.0 27.0 28.0 29.0 30.0 31.0 32.0 33.0
Wet Bulb (C)
COLD
W
TEMPER
C-8.8C B-11.0C A- 13.25C
Test WBT – 25.7 C
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29. CenPEEP
Cooling Tower Thermal Performance Testing
29
Cold Water vs. Cooling Range
30 2
30.4
30.6
30.8
WATER
TURE
(C)
29.4
29.6
29.8
30.0
30.2
8.0 9.0 10.0 11.0 12.0 13.0 14.0
COOLING RANGE (C)
COLD
W
TEMPERAT
COOLING RANGE (C)
90% Flow
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30. CenPEEP
Cooling Tower Thermal Performance Testing
Cold Water vs. Cooling Range
30
31.0
31.5
32.0
MPERATURE
29.0
29.5
30.0
30.5
COLD
WATER
TE
(C)
8.0 9.0 10.0 11.0 12.0 13.0 14.0
COOLING RANGE (C)
C
90% Flow 100% Flow 110% Flow Test Range
Test Cooling Range – 10.1 C
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31. CenPEEP
Cooling Tower Thermal Performance Testing
Cold Water vs. Predicted Flow
30 8
31
30.4
30.6
30.8
ATER
URE
(C)
29 8
30.0
30.2
COLD
WA
EMPERATU
29.6
29.8
80 85 90 95 100 105 110 115
TE
Predicted Flow (%)
Test Cold Water Temp – 35.9 C
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32. CenPEEP
Cooling Tower Thermal Performance Testing
Cold Water vs. Predicted Flow
37.0
RE
32
33.0
35.0
MPERATUR
29.0
31.0
WATER
TEM
(C)
25.0
27.0
25,000 35,000 45,000 55,000 65,000 75,000 85,000
COLD
W
Predicted Flow (t/hr)
Test Cold Water Temp – 35.9 C
Predicted Flow – 77,000 t/hr, Actual Flow - 30,977 t/hr
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33. CenPEEP
DEPOSITS IN FILL
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34. CenPEEP
ALGAE FORMATION
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35. CenPEEP
ONLINE FILL CLEANING RIHAND
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36. CenPEEP
AIR PASSAGE THROUGH SHAFT OPENING
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37. CenPEEP
SEALING OF AIR PASSAGE THROUGH SHAFT
OPENING
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38. CenPEEP
SEALING FAN HUB AREA
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39. SEALING FAN HUB AREA
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40. Rain Water Entering Cold Water Basin
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