Hi

I would like to know how to calculate the "Field thermal power absorbed" using the parabolic trough physical model

I tried using the following

P_abs=DNI*cos(incident_angle)*A_sf*eff_opt

eff_opt=end_loss*shadow*IAM*cos(incident_angle)*SCA_derate*HCE_derate

However, this did not worked

I have read "Technical Manual for the SAM Physical Trough Model" and at page 26 it used almost the same efficieny equation as the above but with out the cosine loss! why is that?

Also on that page the incident energy equation did not work.

Please advise

Regards

Abdullah