Radiation model
 

Hi
I am doing cfd analysis of double pass solar air heater.I am using solar load model for the heating of absorber plate .I have given longitude latitude . Experimentally temperature of plate is 50-55 degree but cfd gives only 42 degree . i have given boundary conditions for absorber plate opaque and .94 absorptivity . and other boundary conditions for glass like semi transparent .
please help me . why temperature of absorber plate is not increasing ?
thank you.