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9-82
9-107 A steam power plant operates on a simple ideal Rankine cycle between the specified pressure limits. The thermal
efficiency of the cycle and the net power output of the plant are to be determined.
Assumptions 1 Steady operating conditions exist. 2 Kinetic and potential energy changes are negligible.
Analysis (a) From the steam tables (Tables A-4, A-5, and A-6),
/kgm 001030.0
kJ/kg 54.340
3
kPa 50 @1
kPa 50 @1
f
f
PPw
hh
v
vv
3
T
9-83
9-108 A simple ideal Rankine cycle with R-134a as the working fluid is considered. The turbine inlet temperature, the cycle
thermal efficiency, and the back-work ratio of the cycle are to be determined.
Assumptions 1 Steady operating conditions exist. 2 Kinetic and potential energy changes are negligible.
9-86
9-111 A steam power plant that operates on a simple ideal Rankine cycle is considered. The quality of the steam at the
turbine exit, the thermal efficiency of the cycle, and the mass flow rate of the steam are to be determined.
Assumptions 1 Steady operating conditions exist. 2 Kinetic and potential energy changes are negligible.
Analysis (a) From the steam tables (Tables A-4, A-5, and A-6),
/kgm 00101.0
kJ/kg 81.191
3
kPa 10 @1
kPa 10 @1
f
f
PPw
hh
v
vv
3
T
9-88
9-113E A simple steam Rankine cycle operates between the specified pressure limits. The mass flow rate, the power
produced by the turbine, the rate of heat addition, and the thermal efficiency of the cycle are to be determined.
Assumptions 1 Steady operating conditions exist. 2 Kinetic and potential energy changes are negligible.
Analysis From the steam tables (Tables A-4E, A-5E, and A-6E),
)(
/lbmft 016230.0
Btu/lbm 02.94
3
psia 2 @1
psia 2 @1
PPw
hh
f
f
v
vv
3
1500 psia
T
9-89
9-114E A simple steam Rankine cycle operates between the specified pressure limits. The mass flow rate, the power
produced by the turbine, the rate of heat addition, and the thermal efficiency of the cycle are to be determined.
Assumptions 1 Steady operating conditions exist. 2 Kinetic and potential energy changes are negligible.
Analysis From the steam tables (Tables A-4E, A-5E, and A-6E),
)(
/lbmft 016230.0
Btu/lbm 02.94
3
psia 2 @1
psia 2 @1
PPw
hh
f
f
v
vv
3
T
9-90
9-115E A steam power plant that operates on a simple ideal Rankine cycle between the specified pressure limits is
considered. The minimum turbine inlet temperature, the rate of heat input in the boiler, and the thermal efficiency of the
cycle are to be determined.
Assumptions 1 Steady operating conditions exist. 2 Kinetic and
potential energy changes are negligible.
T
minimum turbine inlet temperature, the rate of heat input in the boiler, and the thermal efficiency of the cycle are to be
determined.
Assumptions 1 Steady operating conditions exist. 2 Kinetic and potential
energy changes are negligible.
9-92
9-117 A simple Rankine cycle with water as the working fluid operates between the specified pressure limits. The rate of
heat addition in the boiler, the power input to the pumps, the net power, and the thermal efficiency of the cycle are to be
determined.
Assumptions 1 Steady operating conditions exist. 2 Kinetic and potential energy changes are negligible.
Analysis From the steam tables (Tables A-4, A-5, and A-6),
/kgm 001026.0
kJ/kg 03.314
C753.63.813.6
kPa 50
3
C75 @1
C75 @ 1
kPa 50 @sat 1
1
f
f
hh
TT
P
vv
kJ/kg 10.6 mkPa 1
kJ 1
kPa)506000)(/kgm 001026.0(
)(
3
3
121inp,
PPw
v
kJ/kg 13.32010.603.314
inp,12 whh
kJ/kg 4.2336)7.2304)(8660.0(54.340
8660.0
5019.6
0912.17219.6
kPa 50
KkJ/kg 7219.6
kJ/kg 9.3302
C450
kPa 6000
44
4
4
34
4
3
3
3
3
fgsfs
fg
f
s
hxhh
s
ss
x
ss
P
s
h
T
P
kJ/kg 4.2394)4.23369.3302)(94.0(9.3302)( 4s3T34
43
43
T
hhhh
hh
hh
s
Thus,
kW 18,050
kW 122
kW 59,660
122170,18
kJ/kg) kg/s)(6.10 20(
kW 18,170kJ/kg)4.2394.9kg/s)(3302 20()(
kJ/kg)13.320.9kg/s)(3302 20()(
inP,outT,net
inP,inP,
43outT,
23in
WWW
wmW
hhmW
hhmQ
and
0.3025 660,59
050,18
in
net
th Q
W
qin
qout
50 kPa
1
3
2
4
6 MPa
s
T
4s
9-94
9-119 The net work outputs and the thermal efficiencies for a Carnot cycle and a simple ideal Rankine cycle are to be
determined.
Assumptions 1 Steady operating conditions exist. 2 Kinetic and potential energy changes are negligible.
Analysis (a) Rankine cycle analysis: From the steam tables (Tables A-4, A-5, and A-6),
kJ/kg 64.34510.554.340
kJ/kg 10.5 mkPa 1
kJ 1
kPa 505000/kgm 001030.0
/kgm 001030.0
kJ/kg 54.340
in,12
3
3
121in,
3
kPa 50 @1
kPa 05 @1
p
p
f
f
whh
PPw
hh
v
vv
kJ/kg 2.2071
7.23047509.054.340
7509.0
5019.6
09120.19737.5
kPa 50
KkJ/kg 9737.5
kJ/kg 2.2794
1
MPa 5
44
4
4
34
4
3
3
3
3
fgf
fg
f
hxhh
s
ss
x
ss
P
s
h
x
P
kJ/kg 6.244864.3452.2794
23in
hhq
T
1
2
3
4
Rankine
cycle
s
9-96
The Reheat Rankine Cycle
9-121C The T-s diagram of the ideal Rankine cycle with 3 stages of reheat is shown on the side. The cycle efficiency will
increase as the number of reheating stages increases.
1
10
s
T
3
5
7
9
9-98
9-125 A steam power plant that operates on the ideal reheat Rankine cycle is considered. The turbine work output and the
thermal efficiency of the cycle are to be determined.
Assumptions 1 Steady operating conditions exist. 2 Kinetic and potential energy changes are negligible.
Analysis From the steam tables (Tables A-4, A-5, and A-6),
/kgm 700101.0
kJ/kg 42.251
121in,
3
kPa 20 @1
kPa 20 @1
p
f
f
PPw
hh
v
vv
5
T
3
9-100
"Boiler analysis"
Q_in + h[2]+h[4]=h[3]+h[5]"SSSF First Law for the Boiler"
"Condenser analysis"
h[6]=Q_out+h[1]"SSSF First Law for the Condenser"
SOLUTION
Eff=0.358
Eta_p=1
Eta_t=1
0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0
0
100
200
300
400
500
600
700
s [kJ/kg-K]
T [°C]
6000 kPa
2000 kPa
20 kPa
SteamIAPWS
1,2
3
4
5
6
Ideal Rankine cycle with reheat
