# Steam Power Plant Cycles¶

## Example 6.1,Page 366¶

In [1]:
# Initialization of Variable
from math import pi
from math import atan
from numpy import *
P1=200.0 #psia
T1=600.0 #F
P2=2.0 #psia
J=778.0

#calculations
#"from mollier charts,"
h1=1322 #Btu/lb
h2=974 #Btu/lb
vf2=0.01623 #cu ft per lb
hf2=94.0 #Btu/lb
t2=126.0 #F
Wtj=h1-h2
Qout=h2-hf2
Wp=(P1-P2)*vf2
Wpj=Wp/J
h3=hf2+Wpj
Qin=h1-h3
etat=((h1-h2)-Wpj)/(h1-(hf2+Wpj)) #efficiency
eta=((h1-h2))/(h1-(hf2)) #efficiency

#results
print round(etat*100,3),"Efficiency of rankine cycle in percent"
print round(eta*100,3)," Efficiency of rankine cycle neglecting boiler feed pump in percent"

28.339 Efficiency of rankine cycle in percent
28.339  Efficiency of rankine cycle neglecting boiler feed pump in percent


## Example 6.2,Page 366¶

In [1]:
# Initialization of Variable
from math import pi
from math import atan
from numpy import *
B=70 #F
P1=140 #psia
x=0.986
P2=14.7 #psia
ms=2000.0 #lb/hr
Ihp=80.0

#calculations
#"From mollier charts"
hc=38 #Btu/lb
hf=324.82 #Btu/lb
hfg=868.2 #Btu/lb
h1=hf+x*hfg
Qin=ms*(h1-hc)
eta=Ihp*2545*100/(Qin) #efficiency
Qw=Ihp*2545
Qr=Qin-Qw
per=Qr/Qin *100 #percent

#results
print "Heat input to the boiler in Btu/hr",round(Qin,3)
print " Cycle efficiency in percent",round(eta,3)
print " Heat rejected to waste in Btu/hr is",round(Qr,3)," or in percent of Qin",round(per,3)
print "The answer is a bit different due to rounding off error in textbook"

Heat input to the boiler in Btu/hr 2285730.4
Cycle efficiency in percent 8.907
Heat rejected to waste in Btu/hr 2082130.4  or in percent of Qin 91.093
The answer is a bit different due to rounding off error in textbook


## Example 6.3,Page 372¶

In [2]:
# Initialization of Variable
from math import pi
from math import atan
from numpy import *
B=70.0 #F
P1=140.0 #psia
x=0.986
P2=14.7 #psia
ms=2000 #lb/hr
Ihp=80

#calculations
#"From mollier charts"
hc=180.0 #Btu/lb
hf=324.82 #Btu/lb
hfg=868.2 #Btu/lb
h1=hf+x*hfg
Qin=ms*(h1-hc)
eta=Ihp*2545*100/(Qin)
Qw=Ihp*2545 #Btu/hr
Qr=Qin-Qw #Btu/hr
per=Qr/Qin *100 #percent

#results
print "Heat input to the boiler in Btu/hr",round(Qin,3)
print " Cycle efficiency in percent",round(eta,3)
print " Heat rejected to waste in Btu/hr is",round(Qr,3)," or in percent of Qin",round(per,3)
print "The answer is a bit different due to rounding off error in textbook"

Heat input to the boiler in Btu/hr 2001730.4
Cycle efficiency in percent 10.171
Heat rejected to waste in Btu/hr 1798130.4  in percent of Qin 89.829
The answer is a bit different due to rounding off error in textbook


## Example 6.4,Page 380¶

In [10]:
# Initialization of Variable
from math import pi
from math import atan
from numpy import *
m=1.24 #lb
HV=11300 #Btu/lb

#calculations
HR=m*HV
eff=3413/HR #efficiency

#results
print "Plant heat rate in Btu/kw hr",round(HR,3)
print " Overall efficiency in percent",round(eff*100,3)

Plant heat rate in Btu/kw hr 14012.0
Overall efficiency in percent 24.358