This document provides an energy audit of the condenser and condenser cooling water system for a power plant. It includes specifications and measurements for the condenser, cooling towers, cooling water pumps, and related components. The audit involves collecting operational data, evaluating performance against design parameters, investigating issues, and exploring energy conservation opportunities. Recommendations focus on improving condenser vacuum, effectiveness and heat rate; optimizing cooling water flow; upgrading pumps and drives; improving cooling tower performance; and tracking system metrics over time.

1. ENERGY AUDIT OF CONDENSER
AND
CONDENSER COOLING WATER SYSTEM
Manohar Tatwawadi
Director, tops
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2. CONDENSER
• The condensing condenser is the most important
component of the turbine cycle that affects the
turbine heat rate.
• The function of the condenser is to condense
exhaust steam from the steam turbine by
rejecting the heat of evaporation to the cooling
water passing through the condenser.
• Generally, twin shell- double pass- surface type
condensers are employed for higher capacity
units.
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3. Cooling towers:
Different types of
cooling towers are
used in the power
plants depending upon
the location, size,
infrastructure and
water resources etc.
Close cycle – wet
cooling systems:
-Induced draft
-Forced draft
-Natural draft cooling
towers
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4. FORCED DRAUGHT COOLING SYSTEM
ATMOSPHERIC
AIRIN
ATMOSPHERIC
AIRIN
HOT WATER IN
HOT WATER IN
STEAM + GASSES
CT FAN
MOTOR
COLD WATER SUMP
EXHAUST STEAM
FROM TURBINE
CW PUMPCONDENSATE
POND
MAKEUP
WATER
COOLED
WATER
HOT
WATER
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5. COOLING WATER PUMPS
Cooling water pumps:
Circulating water pumps supply cooling water at the
required flow rate and pressure to the power plant
condenser and the plant auxiliary cooling water heat
exchangers. These pumps are required to operate
economically and reliably over the life of the plant.
For once through systems, vertical wet pit pumps are in
common usage.
For re-circulating cooling systems, vertical wet pit and
horizontal dry pit are used about equally, with
occasional use of vertical dry pit pumps.
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6. COOLING WATER PUMP
SPECIFICATIONS
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7. ENERGY AUDIT….STEPS INVOLVED
The major energy consuming equipment in the CW systems are:
• Cooling towers and fans
• Cooling water pumps
• Make up water pumps
• Condensers
The steps involved in conducting energy audit of cooling water and
cooling tower are:
• Data collection
• Observations and Analysis
• Exploration for energy conservation measures
• Report preparation
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8. DATA TO BE COLLECTED…..
Specifications of Cooling Towers
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9. DATA TO BE COLLECTED
Specifications of the Cooling Towers …….
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10. DATA COLLECTION
Specification of water pumps and motors:
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11. DATA COLLECTION
Specification of water pumps and motors- contd…:
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12. DATA COLLECTION…..
Other Information
 Performance characteristics of all pumps and motors
in the CW System.
 Compile design, P. G. Test reports, previous best and
last energy audit values with respect to cooling tower
and cooling water system along with the condensers.
 If the pumps are operated in parallel then it is advised
to collect the performance curve for the parallel
operation.
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13. DATA COLLECTION…..
Other Information
 Schematic diagram of Water pumping network
(which depict the source, pumps in operation &
stand by, line sizes and users)
 Water and pressure measurement and equipment
at the users place as per the design requirements.
 Brief description of the system with the key
specifications in which pumps are used (for
example, if pumps are used for supplying water to
condenser, then add a brief write up about the
cooling water system).
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14. DATA COLLECTION…..
CONDENSER SPECIFICATIONS
Heat load considered for design
Design inlet cooling water temperature/ Design TTD
Cleanliness factor/ Cooling water temperature raise
Condenser back pressure
Cooling water flow/ Cooling water side pressure drop
No of cooling water pass/ Total heat transfer area
No. of tubes - Condensing zone - Air cooling zone
Tube dimensions: - Tube OD x thickness - Length of tube
Tube material: - Condensing zone - Air cooling zone
Water box design pressure
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15. INSTRUMENTS REQUIRED
• Power Analyzer: Used for measuring electrical parameters
of motors such as kW, kVA, pf, V, A and Hz
• Temperature Indicator & Probe
• Pressure Gauge: To measure operating pressure and
pressure drop in the system
• Stroboscope: To measure the speed of the driven
equipment and motor
• Ultra sonic flow meter or online flow meter
• Sling hygrometer or digital hygrometer
• Anemometer, PH Meter.
• In addition to the above, calibrated online instruments
can be used
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16. MEASUREMENTS AND OBSERVATIONS
 Energy consumption pattern of pumps and
cooling tower fans.
 Motor electrical parameters (kW, kVA, Pf, A, V,
Hz, THD) for pumps and cooling tower fans
 Pump operating parameters to be
measured/monitored for each pump are: -
Discharge, - Head (suction & discharge) - Valve
position – Temperature - Load variation, Power
parameters of pumps - Pumps operating hours
and operating schedule
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17. PUMP OPERATING PARAMETERS…
 Pressure drop in the system (between
discharge and user point)
 Pressure drop and temperatures across the
users (heat exchangers, condensers, etc)
 Cooling water flow rate to users - Pump
/Motor speed
 Actual pressure at the user end
 User area pressure of operation and
requirement
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18. MEASUREMENTS and OBSERVATION
 Cooling tower parameters to be monitored
 Inlet temperature
 Outlet temperature
 Dry bulb temperature
 Wet bulb temperature or relative humidity
 Water flow to cooling tower
 Air flow rate of cooling tower
 Range, oC
 L/G ratio
 Approach, oC
 Fan speed, rpm
 Fan power consumption (kW/cell)
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19. OBSERVATIONS and ANALYSIS
 System familiarization and operational details
 Energy consumption Pattern
 The energy consumption of cooling water : kWh/day and
associated system
 Total auxiliary power consumption : kWh/Day
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20. OPERATING EFFICIENCY & PERFORMANCE
EVALUATION OF PUMPS
 Water flow rate and pressure of pumps / headers
 Velocity in the main headers and pumps and major
lines (to verify adequacy of line sizes)
 Power consumption of pumps (for estimating the
operating efficiency of the pumps)
 Monitor present flow control system and frequency of
control valve variation if any (for application of variable
speed drives)
 Fill up the following data sheet for every pump for
comparison with the design / PG test values
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21. OPERATING EFFICIENCY & PERFORMANCE
EVALUATION OF PUMPS
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22. OPERATING EFFICIENCY & PERFORMANCE
EVALUATION OF PUMPS
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23. INVESTIGATION & RECOMMENDATIONS
 Compare the actual values with the design / performance test
values if any deviation is found, investigate for the contributing
factors and arrive at appropriate suggestions
 The investigations for abnormality are to be carried out for
problems. Enlist scope of improvement with extensive physical
checks / observations.
 Based on the actual operating parameters, enlist
recommendations for action to be taken for improvement, if
applicable such as
 Replacement of pumps/ Impeller replacement/ trimming
 Variable speed drive application, etc
 Compare the specific energy consumption with similar type of
pumps and latest energy efficient pumps
 Cost analysis with savings potential for taking improvement
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24. FLOW DISTRIBUTION
• Measure the flow at the individual pump discharge side,
main header, at the users (for the major and large users)
along with the pressure and velocity. Depict these values in
schematic diagram.
• Ensure Line adequacy by measuring the velocity in the major
pipe lines.
• Pressure drop in the distribution network
• Specific water flow rate
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25. PERFORMANCE of CONDENSERS
Parameters to be monitored
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26. PERFORMANCE of CONDENSERS
Parameters to be monitored …….
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27. PERFORMANCE of CONDENSERS
Parameter Details Unit
Q Water flow rate Kg/h
T Average CW temperature rise oC
Cp Specific heat kcal/kg oC
The following needs to be computed:
1. Condenser heat load = Q x T x Cp
2. Calculated condenser vacuum = Atmospheric pressure – Condenser back
pressure
3. Deviation in condenser vacuum= Expected condenser vacuum - Measured
condenser vacuum
4. Condenser TTD = Saturation temperature – Cooling water outlet
temperature
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28. CONDENSER PERFORMANCE
5. Condenser Effectiveness =
Rise in cooling water temperature
Saturation temperature - Cooling water inlet temperature
6. Condenser heat duty in kcal/h =
Heat added by main steam + heat added by reheater + heat added by
SH attemperation + heat added by RH attemperation + heat added by
BFP - 860 x (Pgen + Pgen losses + heat loss due to radiation)
7. Condenser tube velocity (m/s) =
Cooling water flow rate (m3/h) x 106
3600 x tube area (mm2) x ( no. of tubes per pass - no. of tubes plugged
per pass )
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29. 8. Determination of actual LMTD
9. LMTD expected = LMTD test x ft x fw x fq
ft : Correction for cooling water inlet temperature
fw : Correction for water flow rate and
fq : Correction for cooling water heat load
Tsat - Tout
Ln
LMTD TEST =
Tout - Tin
Tsat -Tin
CONDENSER PERFORMANCE
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30. LMTD Corrections..
ft =
fw =
Tube velocity during test
Tube velocity design( )
0.50
fq =
Condenser design duty
Condenser duty during test( )
fw: Correction for water flow rate
fq: correction for cooling water heat load
Saturation Temperature during test – LMTD during test
Saturation Temperature design – LMTD design
ft: Correction for cooling water inlet temperature
0.25
( )
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31. OBSERVATIONS
• Condenser Tubes in operation Vs total tubes
installed
• Cleaning system operation Online/offline
• Filtering system for cooling water, Strainers checking
regularity
• Regular monitoring system for performance
Comparison of LMTD, TTD, heat load, condenser
vacuum, flow, temperatures, pressures with design /
PG test- arriving the factors causing deviation
• Cooling water flow
• Accurate metering of vacuum
• Pressure drop on water side and choking
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32. OBSERVATIONS
• Modifications carried out in the recent past
• Affect of present performance of cooling tower
• Absolute back pressure deviation from expected
value
• Sub cooling of air –steam mixture and
condensate
• Circulation water temperature raise
• Effectiveness of cleaning the tubes
• Circulating water velocity in tubes
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33. PERFORMANCE of COOLING TOWERS
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34. COOLING TOWER PERFORMANCE
 While conducting the cooling tower performance test, visual
observations need to be made with respect to:
• Adequate water level in the trough
• Cross flow air from other cooling towers (which are under
• maintenance)
• Nozzle condition and operation
• Fill condition
• Change of blade angles during change of seasons
 The CT airflow shall be measured using an anemometer and
compared with calculated airflow derived from fan characteristic
curves of CT fans with actual power measurements.
 Calculate range, approach, L/G (Liquid to gas) ratio and
effectiveness for design and operating conditions for each tower
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35. COOLING TOWER PERFORMANCE
1. C.T. Range = Water inlet temperature – Water outlet temp.
2. C.T. Approach = Water outlet temperature – Wet bulb temp.
3.
4.
Effectiveness % =
Range x 100
( range + approach )
Fan actual airflow (Nm3) / cell =
Fan rated airflow (Nm3) / h x ( Fan input kW actual )
( Fan input rated )
1/3
1/3
5. Air mass flow / cell = flow x density of air
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36. COOLING TOWER PERFORMANCE
5. Evaporation losses =
CW flow (m3/ h) x CT range in 0C
675
6. Makeup water consumption =
Evaporation losses
(COC – 1)
 The above readings may be taken on daily basis for three
days on different atmospheric conditions say during mid
summer, winter & monsoon period. Once in the mid day
and once in the mid night time and a record duly
maintained.
 Collect unit load (MW), frequency, and condenser vacuum
condition while taking the cooling tower measurement
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37. PERFORMANCE of COOLING TOWERS
Power consumption of CT fans
Exploration of Energy Conservation Possibilities:
Condenser
• Possibility of Improvement in condenser vacuum
• Turbine heat rate Reduction possibilities
• Improving the effectiveness of condenser and TTD
• Cooling water flow adequacy and flow optimization
• Air ingress
• Increasing the TTD of the condenser
• Fouling of tubes
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38. ENERGY CONSERVATION POSSIBILITIES
Water pumping and cooling tower
• Improvement of systems and drives
• Use of energy efficient pumps
• Correcting inaccuracies of the Pump sizing / Trimming of impellers
• Use of high efficiency motors
• Integration of variable speed drives into pumps: The integration of
adjustable speed drives (VFD) into compressors could lead to energy
efficiency improvements, depending on load characteristics
• High Performance Lubricants: The low temperature fluidity and high
temperature stability of high performance lubricants can increase energy
efficiency by reducing frictional losses
• Improvements in condenser performance
• Improvement in cooling tower performance
• Application potential for energy efficient fans for cooling tower fans
• Measuring and tracking system performance
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39. ENERGY CONSERVATION POSSIBILITIES
• Measuring water use and energy consumption is essential
in determining whether changes in maintenance practices
or investment in equipment could be cost effective
• In this case it is advised to monitor the water flow rate and
condenser parameters, cooling tower parameters
periodically i.e. at least once in a three months and energy
consumption on daily basis. This will help in identifying the
- Deviations in water flow rates
- Heat duty of condenser and cooling towers
- Measures to up keep the performance
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40. EXPLORATION.. ENERGY
CONSERVATION
• Internal Running Clearances: The internal running clearances
between rotating and non-rotating elements strongly
influence the turbo machine's ability to meet rated
performance. Proper set-up reduces the amount of leakage
(re-circulation) from the discharge to the suction side of the
impeller.
• Reducing work load of pumping: Reducing of obstructions in
the suction / delivery pipes thereby reduction in frictional
losses. This includes removal of unnecessary valves of the
system due to changes. Even system and layout changes may
help in this including increased pipe diameter. Replacement of
components deteriorated due to wear and tear during
operation, modifications in piping system
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