Document Text Contents
Page 58
UNIVERSITY OF
FLORIDA
Thermodynamics
P
h
Consider a steam power plant and assume an
ideal Rankine cycle to model the system.
The steam enters the turbine at 3MPa and 350 C
Condenser pressure is at 75 kPa.
What is the thermal efficiency for this cycle?
th,Rankine = wnet/qin= (qin – qout)/qin
qin = h1 – h4
qout = h3-h2
h1 = h of superheated steam = 3115.3 kJ/kg
s1 = s2 = 6.7428 kJ/kg K
s2 = sf75kPa + x sfg75kPa = 6.7428 kJ/kg K
x = (6.7428-1.213)/6.2434 = 0.88
Using x and hf75kPa and hfg75kPa, we can calc.
h = 384.39+(0.88)(2278.6)= 2402.6 kJ/kg
1
2
3
4
UNIVERSITY OF
FLORIDA
Thermodynamics
P
h
Consider a steam power plant and assume an
ideal Rankine cycle to model the system.
The steam enters the turbine at 3MPa and 350 C
Condenser pressure is at 75 kPa.
What is the thermal efficiency for this cycle?
th,Rankine = wnet/qin= (qin – qout)/qin
qin = h1 – h4
qout = h3-h2
h1 = h of superheated steam = 3115.3 kJ/kg
s1 = s2 = 6.7428 kJ/kg K
s2 = sf75kPa + x sfg75kPa = 6.7428 kJ/kg K
x = (6.7428-1.213)/6.2434 = 0.88
Using x and hf75kPa and hfg75kPa, we can calc.
h = 384.39+(0.88)(2278.6)= 2402.6 kJ/kg
1
2
3
4
