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clear;
clc;
printf('FUNDAMENTALS OF HEAT AND MASS TRANSFER \n Incropera / Dewitt / Bergman / Lavine \n EXAMPLE 12.11 Page 774 \n')// Example 12.11
// Useful heat removal rate per unit area
// Efficiency of the collector
Ts = 120+273; //[K] temperature of surface
Gs = 750; //[W/m^2] Solar irradiation
Tsky = -10+273; //[K] Temperature of Sky
Tsurr = 30+273; //[K] Temperature os surrounding Air
e = .1 ;// emissivity
as = .95 ;// Absorptivity of Surface
asky = e ;// Absorptivity of Sky
stfncnstt = 5.67*10^-8; //[W/m^2.K^4] Stefan-Boltzmann constant
h = 0.22*(Ts - Tsurr)^.3334 ;//[W/m^2.K] Convective Heat transfer Coeff
//From equation 12.67
Gsky = stfncnstt*Tsky^4; //[W/m^2] Irradiadtion from sky
qconv = h*(Ts-Tsurr); //[W/m^2] Convective Heat transfer
E = e*stfncnstt*Ts^4; //[W/m^2] Irradiadtion from Surface
//From energy Balance
q = as*Gs + asky*Gsky - qconv - E;
//Collector efficiency
eff = q/Gs;
printf('\n Useful heat removal rate per unit area by Energy Conservation = %i W/m^2 \n Collector efficiency defined as the fraction of solar irradiation extracted as useful energy is %.2f',q,eff);
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