Condenser performance is dependent on several factors including vacuum level, cooling water temperature rise, fouling, and scaling. There are two main types of condensers - water cooled and air cooled. Water cooled condensers use cooling water to remove heat from exhaust steam via a shell and tube heat exchanger. Condenser performance decreases over time due to fouling of the tubes which reduces the heat transfer coefficient. Fouling can be caused by air binding, biofouling, scaling, or silting in the tubes. Regular monitoring and cleaning is needed to maintain condenser performance.

1. What are factors affectingcondenserperformance?
Condenseristhe mainheatsinkinthe entire powercycle.Plantheatrate ismostly dependingon
condenserperformance. There are twotypesof condenserare availableinpowerplant, one iswater
cooledandanotherisair cooledcondenser.Aircooled condenseris consideredwhenthereiswater
availabilityisless. Isentropicheatdropsthoughthe turbine dependsonthe inletsteampressure &
temperature andcondenservacuum.If the vacuumincondenserislower,the workdone bythe turbine
will be reduced.
In case of watercooledcondensercoolingwatersuppliedto the surface condensertube sidetocool the
exhauststeamfromthe turbine. Inthisprocess undissolved airorgassesare separated andisevacuated
fromthe shell side byejectorof vacuumpumpto maintainthe vacuum. Normallyitistwopass , shell
and tube type heatexchanger. We needtofamiliarize withthe followingterms:
TTD- Terminal temperature difference =T3- T2
T3 – ExhaustSteam(Saturation) temperature,T2- CW outletTemperature
TR- Temperature Difference =T2- T1
T1- CW inlettemperature
CondenserEfficiency= (CW temperature rise)/(MaximumTemp Difference)
= TR/ (T3- T1)x100%
dTm=LMTD= Log mean temperature difference
= (T2-T1)/((ln(T3-T1)/(T3-T2))

2. CW Mass Flow Rate , m= dUA,where
d – densityof water
U- velocityof water
A-condensersurface area
Q= Heat transfer rate in condenser=K.A.dTm =m.Cp .(T2-T1) consideringno otherheat loss taking
place insteady state condition
K- heat transfercoefficientof tube
A-Surface area
m- massflowrate (CW)
Cp- specificheatof water
So. CondenserEffectivenessisdependson CWtemperature difference orratioof temperature
difference,specificheatof water,massflow rate of coolingwater,heattransfercoefficientof condenser
tube and surface areaof condensertubes.
CleanlinessFactor:CF= Kt/Ki ,,Ki isinitial heattransfercoefficient ,thiscanbe derivedfromthe above
formula.
Kt isheat transfercoefficient afterTime t.

3. CF is100% whenit isnewand cleanedcondition.Afterrunningsometimethisvalue will be reduced.
Normallysystemisdesignedfor85%CF.
FoulingFactor: FF= 1/Kt-1/Ki , thisfactor isusedto predictthe performance trendof the condenser
Theoretically1mmHgreductioninvacuumgenerationlossof 4MW and there is2.5% of efficiencyloss.
Condenserperformance candegrade due tofollowingreason:
 Airbindingonthe shell side: Thisisdue topoor performance of the steamejector/vacuum
pumpor air ingressintothe system.
 Biofouling:This can be avoidedbyproperchlorinationof the CWsystem
 Scaling:ProperCW quality- pH,TDS,hardness,COC,conductivityetcare tobe maintainedto
avoidthe scalinginside the tube surface.
 Silting:Obstructioninthe tubescan occurs due to siltdepositionandchokingof the tubesby
filmof coolingtowerordebriscarriedawayby coolingwater.
Dailymonitoringof TTD,TR, CF and FF easilywillshow the gradual deteriorationof the parameters.
Remedies:
 Online condensertube cleaningsystemwill helptomaintainthe above parameters
 Chemical treatmentof CoolingWaterandmonitoringof coolingwaterparametersare required
 Inspectionandcleaningof waterbox,tubesare tobe done duringperiodical shutdown

4.  If the hard scale isformedinside the tube,,chemical cleaningisbe done
 Pluggedtubesare tobe replacedduringshutdownof the unit.Itshouldnotexceed5% of the
total tubes.