import math
# Variables
T1 = 261.15; #[K] Temgeratureof refrigerated space
T2 = 294.15; #[K] Temperature of cooling water
dT = 5.6; #[K] Temperature Difference
Qc = 35.2; #[kW] Refrigerant Capacity
eta = 0.8; #Efficeincy(b)
# Calculations and Results
#(a) Carnot Refrigerator
Tc = T1-dT;
Th = T2+dT;
#Umath.sing Eqn(9.3)
w = round(Tc/(Th-Tc),2);
print '(a)Coefficient of Performance for Carnot Refrigerator',w
#(b) Vapor Compression Cycle
#From Table(9.1)
#@ Tc = 255.55K
H2 = 388.13; #[KJ/Kg]
S2 = 1.7396; #[KJ/Kg/K]
#@ Th = 299.75K
H4 = 236.76; #[KJ/Kg]
S3 = S2; #Isentropic
#Hence
H3 = 420.27; #[KJ/Kg]
#Step 2 --> 3
del_Hs = H3-H2;
#But Compressor Efficiency = 0.80
del_Hs = del_Hs/eta
#Step 1 --> 4
H1 = H4; #isenthalpic
w = round((H2-H4)/del_Hs,2);
print '(b)Coefficient of Performance for Vapor Compression Cycle',w
rm = round(Qc/(H2-H4),4); #[Kg/s]
print 'Circulation rate',rm,'kg/s'
import math
# Variables
Qh_Winter = 30.; #[KW]
Qc_Summer = 60.; #[KW]
Tc_Winter = 283.15; #[K]
Th_Winter = 303.15; #[K]
Tc_Summer = 278.15; #[K]
Th_Summer = 298.15; #[K]
# Calculations and Results
#For WINTER's
#Using Eqn(5.7)
Qc_Winter = Qh_Winter*(Tc_Winter/Th_Winter);
#Umath.sing Eqn(9.1)
W_Winter = round((Qh_Winter-Qc_Winter),2); #[KW]
print "Power Requirement for WINTER''s",W_Winter,'KW'
#For SUMMER's
#Combining Eqn(9.2) And Eqn(9.3)
W_Summer = round((Qc_Summer*((Th_Summer-Tc_Summer)/Tc_Summer)),2);
print "Power Requirement for SUMMER''s",W_Summer,'KW'
import math
# Variables
x = 0.25;
#For Superheated Methane
#By Perry and Green by linear interpolation
H4 = 1140.; #[KJ/Kg] @ 300K and 60 Bar
H15 = 1188.9; #[KJ/Kg] @ 295K and 1 Bar
#By interpolation based on lnP
T_sat = 111.5; #[K]
H9 = 285.4; #[KJ/Kg] Saturated Liquid
H12 = 769.9; #[KJ/Kg] Saturated Vapor
S12 = 9.521; #[KJ/Kg/K] Saturated vapor
T5 = 253.6; #[K]
H5 = 1009.8; #[KJ/Kg] @ 60 Bar
#From Eqn(9.7)
z = ((x*(H12-H5))+H4-H15)/(H9-H15);
H14 = ((H5-H4)/(1-z))+H15; #[KJ/Kg]
#Whence
T14 = 227.2; #[K] @ 1Bar
H7 = H5-((1-z)/(1-x)*(H14-H12)); #[KJ/Kg]
T7 = 197.6; #[K] @ 60Bar
#From Eqn(9.8)
z = round((H4-H15)/(H9-H15),4);
H7 = H4-((1-z)*(H15-H12));
T7 = 206.6; #[K]
# Results
print 'Fraction of methane liquefied',z*100,'%'
print 'Temperature of High Pressure steam entering the throttle valve',T7,'K'