Combined cycle power plants (CCPPs) are in operation with diverse thermodynamic cycle configurations. Assortment of thermodynamic cycle for scrupulous locality is dependent on the type of fuel available and different utilities obtained from the plant. In the present paper, seven of the practically applicable configurations of CCPP are taken into consideration. Exergetic and energetic analysis of each component of the seven configurations is conducted with the help of computer programming tool, i.e., engineering equation solver (EES) at different pressure ratios. For Case 7, the effects of pressure ratio, turbine inlet temperature and ambient relative humidity on the first and second law is studied. The thermodynamics analysis indicates that the exergy destruction in various components of the combined cycle is significantly affected by the overall pressure ratio, turbine inlet temperature and pressure loss in air filter and less affected by the ambient relative humidity.
Pressure losses in air filter at 100% air flow/mbar
3.5
Relative humidity at air humidifiers outlet/%
100
Pressure drop for air in the air intercooler/%
1
The pressure drop for air in the AC/%
1
Pressure drop for gas in the regenerative HE/%
2
Pressure drop in the CC and REH/%
4
Pressure drop in the waste heat recovery boiler/%
4
Effectiveness for the AC/%
85
Effectiveness of the air intercooler/%
90
Effectiveness of the regenerative HE/%
55
Compressor isentropic efficiency/%
87
GT isentropic efficiency/%
89
Efficiency of the CC and REH/%
95
Generator efficiency/%
97
Steam pressure at the ST inlet/bar
25
Steam temperature at the ST inlet/K
567
ST exhaust pressure/bar
0.09
Temperature rise of cooling water in condenser/K
283.98
Cooling water inlet temperature in condenser/K
298
Cooling water outlet temperature from condenser/K
309
Stack temperature/K
413
Pump isentropic efficiency/%
85
Turbine isentropic efficiency/%
85
Tab.2
Fig.9
Fig.10
Fig.11
Fig.12
Fig.13
Fig.14
Fig.15
Fig.16
Fig.17
Fig.18
Fig.19
Fig.20
Fig.21
Fig.22
Fig.23
Fig.24
Fig.25
Fig.26
Fig.27
Fig.28
Fig.29
Fig.30
Fig.31
Fig.32
Fig.33
Fig.34
Fig.35
Fig.36
Fig.37
E·
Exergy rate/(kJ·s−1)
LHV
Lower heating value
R
Gas constant/(kJ·kg−1·K−1)
RH
Relative humidity
T
Absolute temperature/K
W
Work/(kJ·kg−1 (dry air))
cp
Specific heat at constant pressure/(kJ·kg−1·K−1)
cv
Specific heat at constant volume/(kJ·kg−1·K−1)
e
Specific exergy/(kJ·kg−1 (dry air))
h
Enthalpy/(kJ·kg−1 (dry air))
hf
Enthalpy of saturated water at process steam pressure
hg
Enthalpy of saturated vapor at process steam pressure
m
Mass/kg
n
Number of moles
p
Pressure/bar
Qp
Process heat/(kJ·kg−1 (dry air))
rp
Compression ratio
s
Entropy/(kJ·kg−1·K−1)
t
Temperature/K
V
Specific volume/(m3·kg−1)
Tab.3
ω
Humidity ratio (kg of water vapor per kg of dry air)
φ
Relative humidity/%
ε
Effectiveness/%
η
Efficiency/%
γ
Specific heat ratio
Tab.4
AC
Air compressor
CC
Combustion chamber
D
Destruction
GT
Gas turbine
P
Product
Q
Heat
R
Regenerator
SG
Steam generator
W
Work
a
Ambient air
av
Average
f
Fuel
g
Gas
i
Inlet
l
Liquid
o
Outlet
sat
Saturated
v
Water vapor
w
Water
Tab.5
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