Reference / Incidence-angle modifier, beam
Model option
Module IAM profile
The incidence-angle curve carried in the module file
Inputs used: ASHRAE b₀, AR-coated glass, module.iam_angles_deg, iam.angles_deg
Method
The accepted fraction is read from the incidence-angle table carried in the module file. The file also states how the table is interpolated, its IAM mode (the IAM table rule of the Module tab). A table of the Fresnel kind, or one without a mode, is linear from (0°, 1) to its first angle and on its first and last segments, and follows the cubic through the four nearest angles on the segments between. A user table gets a (0°, 1) point when it has none, follows quadratics through three points on its first and last segments and cubics between, and is held between 0 and 1. A module in the ASHRAE mode uses the ASHRAE formula with the coefficient of the Module tab. Angles beyond the last point of a table give 0.
References
- IEC 61853-2:2016, Photovoltaic module performance testing and energy rating, Part 2: spectral responsivity, incidence angle and module operating temperature measurements
API
iam.kind = module_profile