In [1]:

```
#A rankine cycle operates with steam conditions 200 psia,750 F and exhaust
#pressure 1 psia. Find the heat supplied, the turbine work, and the pump work
#per pound of steam. Find the cycle efficiency and steam rate?
#initialisation of variables
P= 1 #psia
P1= 200 #psia
T= 750 #F
v3= 0.01614 #cu ft/lb
h1= 1399.2 #Bu/lb
h2= 976 #Btu/lb
h3= 69.7 #Btu/lb
#CALCULATIONS
dh= v3*(144./778.)*(P1-P) #Change in enthalpy
h4= h3+dh #Enthalpy 4
Q1= h1-h4 #Heat
Wt= h1-h2 #Work
Wp= h4-h3 #Work
n= (Wt-Wp)/Q1 #Efficiency
w= 2545./Wt #Steam rate
#RESULTS
print '%s %.3f' %('cycle efficency = ',n)
print '%s %.2f' %(' \n steam rate (lb steam per hphr) = ',w)
raw_input('press enter key to exit')
```

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In [ ]:

```
#A turbine operating under the same steam conditions as given for the cycle
#of example 1 has a measured steam rate 8. Find the engine efficiency of the
#tuebine and the state of the exhaust steam.
#initialisation of variables
wt= 8. #lb/hphr
h1= 1399.2 #Btu/lb
h2s= 976. #Btu/lb
h2= 976. #Btu/lb
#CACLAULATIONS
Wt= 2545./wt #Work per piund
nt= Wt/(h1-h2s) #Efficiency
h21= h1-Wt #State of echaust steam
#RESULTS
print '%s %.3f' %('Engine efficency = ',nt)
print '%s %.3f' %(' \n state of the exhaust steam (Btu/lb) = ',h21)
raw_input('press enter key to exit')
```

In [1]:

```
#A reheat cycle is to operate with turbines of 85% efficiency, but otherwise
#with idealized processes. the initial pressure is 2000 psia, and exhaust pressure
#is 0.5 psia, reheat=400 psia. Max. temp=1000 F. find efficiency and steam rate
#of this cycle. also of a rankine cycle working between 2000, 1000 and 0.5; also
#of a rankine cycle between 1400,1000,0.5. this being taken as cycle of max.
#permissible pressure without reheat. Use turbines oof 85% efficiecy in the rankine cycles
import math
print '%s' %('All the values have been obtained from steam tables and mollier chart')
#initialisation of variables
h1=1474.5 #btu/lb
s1=1.5603 #btu/lb R
h2s=1277.5 #btu/lb
#Calculations and printfing
h2=h1-0.85*(h1-h2s)
print '%s %.2f' %('h2 (Btu/lb) = ',h2)
h3=1522.4 #btu/lb
s3=1.7623 #btu/lb R
h4s=948 #btu/lb
h4=h3- 0.85*(h3-h4s)
print '%s %.2f' %('\n h4 (Btu/lb) = ',h4)
h5=47.6 #btu/lb
h6=53.5 #btu/lb
print ('\n For the first rankine cycle')
h7s=840 #btu/lb
h7=h1-0.85*(h1-h7s)
print '%s %.2f' %('\n h7 (Btu/lb) = ',h7)
print ('\n For the second rankine cycle')
h8=1493.2 #btu/lb
s8=1.6903 #btu/lb R
h9s=866 #btu/lb
h9=h8-0.85*(h8-h9s)
print '%s %.2f' %('\n h9 (Btu/lb) = ',h9)
h11=51.5 #btu/lb
n1=0.401
n2=0.375
n3=0.366
e1=(n1-n2)/n2 #Efficiency
print '%s %.2f' %('\n Percentage Efficiency of reheat cycle compared to Rankine cycle for the first case =',e1*100)
e2=(n1-n3)/n3 #Efficiency
print '%s %.2f' %('\n Percentage Efficiency of reheat cycle compared to Rankine cycle for the second case =',e2*100)
raw_input('press enter key to exit')
```

Out[1]:

In [2]:

```
#A steam plant operates with initial pressure 250 psia and temp 700 F and exhausts
#to a heating system at 25 psia. the condensate from the heating system is
#returned to the boiler plant at 150F, and the heating system utilizes for its
#intended purpose 90% of the energy transferred from the steam it receives
#(a) what fraction of energy supplied to the steam plant serves a useful purpose?
#(b) If two separate steam plants had been setup to produce the same useful energy,
#one to generate power through a cycle working between 250 psia, 700 F and 1 psia,
#what fraction of energy supplied would have served a useful purpose?
#initialisation of variables
h1= 1371 #Btu/lb
h2s= 1149 #Btu/lb
h3= 118 #Btu/lb
Q1= 1253 #Btu/lb
W= 156. #Btu/lb
Qw= 680. #Btu/lb
#CALCULATIONS
print '%s' %('All the values have been obtained from steam tables and mollier chart')
Qh= h1-W-h3 #Heat
y= W+0.9*Qh #useful energy
r= y/Q1 #fraction
x= Qh+Qw #total input
z= y/x #fraction
#RESULTS
print '%s %.2f' %('Fraction of energy supplied = ',r)
print '%s %.2f' %(' \n Fraction of energy supplied which appears as useful energy= ',z)
raw_input('press enter key to exit')
```

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