clc
T0 = 300 // Atmospheric temperature in K
Tg1_ = 300 // Higher temperature of combustion product in degree Celcius
Tg2_ = 200 // Lower temperature of combustion product in degree Celcius
Ta1 = 40 // Initial air temperature in K
cpg = 1.09 // Specific heat capacity of combustion gas in kJ/kgK
cpa = 1.005// Specific heat capacity of air in kJ/kgK
mg = 12.5 // mass flow rate of product in kg/s
ma = 11.15// mass flow rate of air in kg/s

printf("\n Example 8.8")
Tg1 = Tg1_+273 // Higher temperature of combustion product in K
Tg2 = Tg2_+273 // Lower temperature of combustion product in K
f1 = cpg*(Tg1-T0)-T0*cpg*(log(Tg1/T0)) // Initial availability of product
f2 = cpg*(Tg2-T0)-T0*cpg*(log(Tg2/T0)) // Final availability of product
printf("\n The initial and final availability of the products are %f kJ/Kg and %f kJ/Kg respectively",f1,f2)
//The answer provided in the textbook is wrong

// Part (b)
Dfg = f1-f2 // Decrease in availability of products
Ta2 = (Ta1+273) + (mg/ma)*(cpg/cpa)*(Tg1-Tg2) // Exit temperature of air
Ifa = cpa*(Ta2-(Ta1+273))-T0*cpa*(log(Ta2/(Ta1+273))) // Increase in availability of air
I = mg*Dfg-ma*Ifa // Irreversibility 
printf("\n The irreversibility of the process is %f kW",I)
////The answer provided in the textbook contains round off error

// Part (c)
Ta2_ = (Ta1+273)*(Tg1/Tg2)^((12.5*1.09)/(11.5*1.005))
Q1 = mg*cpg*(Tg1-Tg2) // Heat supply rate from gas to working fluid
Q2 = ma*cpa*(Ta2_-(Ta1+273))// Heat rejection rate from the working fluid in heat engine
W = Q1-Q2 // Power developed by heat engine
printf("\n Total power generated by the heat engine is %f kW",W)
//The answer provided in the textbook contains round off error