Incidence Angle Modifier Coefficients - Parabolic Trough-Heat

Hello,

I am currently working on a simulation with the Cylindrical-Parabolic model using a different collector than the ones available in the database, I would like to know if in the option Incidence Angle Modifying Coefficients (IAM) you should place the values of the longitudinal or transverse IAM coefficients.


Best regards,
Willian Carrión

Hi Willian,

The "Parabolic Trough - Heat" model assumes that the parabolic trough tracks the sun such that the plane of the aperture is perpendicular to the plane defined by the sun and receiver. As such, the transversal incidence angle is always 0, and the IAM is a function of the longitudinal incidence angle.

Thanks,

Ty

Thank you very much for the explanation Ty,  

But I have another doubt, could you help me to solve it?  I have been reviewing the equation proposed by the SAM manual (Equation 2.42 of the manual:  www.nrel.gov/docs/fy11osti/51825.pdf ) for the angle of incidence modifier.  The IAM coefficients for the Euro Trough ET150 collector shown by SAM are 1; 0.0506; -0.1763 and 0 ; however, according to what is stated in this article( citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.847.8570&rep=rep1&type=pdf ) the coefficients for that same collector model are 1; 0.000884 and - 0.00005369 . So why the different values of the coefficients if the collector model is the same ?

On the other hand, in the simulation I am working on I use a commercial collector different from the ones in the program, and I have no information of the IAM coefficients of this specific collector; would it be feasible to use values of the coefficients of the collector models available in SAM or maybe there are standard values ?


Regards, 
Willian

Hi Willan,

I don't have an explanation of why the coefficients in those two publications are different.

If you don't have data for the specific collectors you are using, the default values should be good enough to give you a reasonable estimate of the total annual output of the system.

Best regards,
Paul.

Thanks for your support Paul