pvlib.iam.ashrae#
- pvlib.iam.ashrae(aoi, b=0.05)[source]#
Determine the incidence angle modifier using the ASHRAE transmission model.
The ASHRAE (American Society of Heating, Refrigeration, and Air Conditioning Engineers) transmission model is developed in [1], and in [2]. The model has been used in software such as PVSyst [3].
- Parameters:
aoi (numeric) – The angle of incidence (AOI) between the module normal vector and the sun-beam vector in degrees. Angles of nan will result in nan.
b (float, default 0.05) – A parameter to adjust the incidence angle modifier as a function of angle of incidence. Typical values are on the order of 0.05 [3].
- Returns:
iam (numeric) – The incident angle modifier (IAM). Returns zero for all abs(aoi) >= 90 and for all
iamvalues that would be less than 0.
Notes
The incidence angle modifier is calculated as
\[IAM = 1 - b (\sec(aoi) - 1)\]As AOI approaches 90 degrees, the model yields negative values for IAM; negative IAM values are set to zero in this implementation.
References
