/*
Example Problem 4.10 - Usina de Recuperação de Calor
*********************************************************************
*/

// Análise Energética

// a) Potencia da turbina

// Mass balance

0 = mdot1 - mdot2
0 = mdot3 - mdot4
0 = mdot4 - mdot5

// Energy balance

Wdot = mdot1/60 * (h1 - h2) + mdot3/60 * (h3 - h5)

WdotE = Wdot*60 /1.0551

// known conditions

p1E=14.7 	// lbf/in2
p1=p1E*0.0689476  // bar
T1E=860 	      // R
T1=T1E/1.8  // K
p2E=14.7  // lbf/in2
p2=p2E*0.0689476  // bar
T2E=720            // R
T2=T2E/1.8  // K
av1E=2*10^5     // ft3/min
av1=av1E*0.028317  // m3/min
rbarE=1545  // ft lbf/lbmol R
rbar=8.314  // kJ/kmol K
m=28.97  // mol do ar
mdot3E=275  // lb/min
mdot3=275*0.4536  // kg/min
p3E=40 // lbf/in2
p3=p3E*0.0689476  // bar
T3E=562  // R
T3=T3E/1.8  // K
x5=0.93
p5E=1 // lbf/in2
p5=p5E*0.0689476  // bar
p4=p3
celet = 0.08  // $/kWh

// Mass flow rate and properties

mdot1E = av1E * p1E * 144 / (rbarE/m) / T1E  // lb/min

mdot1 = av1 * p1 * 10^2 / (rbar/m) / T1  // kg/min

h1 = h_T("Air", T1)
h2 = h_T("Air", T2)
h3= h_PT("Water/Steam", p3, T3)
h5 = hsat_Px("Water/Steam", p5, x5) 

// b) Temperatura na entrada da turbina: T4

// balanco de energia no gerador de vapor

0 = mdot1 * (h1 - h2) + mdot3 * (h3 - h4)

T4 = T_Ph("Water/Steam", p4, h4)  

T4R=T4*1.8

T4F = T4R - 460

// c) Ganho ($/ano) para operacao anual de 8000 h

VA = Wdot * 8000 * celet