2- The last term in the equation used to calculate the IAM in the manual is 1.4272E-8 while in the code is 1.472E-8
3- Different equations than those indicated in the manual are used to calculate the effective angle of sky diffuse and ground diffuse radiation
4- The variable SUNGND (surface ground diffuse radiation) is not calculated anywhere in the code and it is not one of the inputs
5- The reference efficiency EFFREF does not account for the module surface area so I believe it should equal: Vm*Im/SUNR*Area instead of Vm*Im/SUNR
6- Equation 5.2.5-21 used to calculate the cell temperature in the manual (page 74) I believe is incorrect [It should be UL*(Tc-Ta)=TAU_Alpha*Gt*(1-Eff/TAU_Alpha) thus Tc=Ta+ TAU_Alpha*Gt*(1-Eff/TAU_Alpha)/UL ] (The equation is however applied correctly in Type94 code script)
7- Finally, I found out why Type94a overestimates the IAM losses (when the option is activated). This is because the SUN variable, (Effective global tilted irradiance) is calculated after multiplying each irradiance component IAM multiplier (i.e. TADIR, TAGND, TADIFF) by TAMAX (TAU-ALPHA at normal incidence), which i believe is incorrect as the IL at reference conditions already includes the effect of TAU-ALPHA at normal incidence. This error is however corrected when the IAM mode is disabled where the SUN variable is not multiplied by TAMAX
could someone confirm the aforementioned bugs?
Thank you
Regards,
Amir