Calculates the SAPM effective irradiance using the SAPM spectral loss and SAPM angle of incidence loss functions.

Parameters
• poa_direct (numeric) – The direct irradiance incident upon the module. [W/m2]

• poa_diffuse (numeric) – The diffuse irradiance incident on module. [W/m2]

• airmass_absolute (numeric) – Absolute airmass. [unitless]

• aoi (numeric) – Angle of incidence. [degrees]

• module (dict-like) – A dict, Series, or DataFrame defining the SAPM performance parameters. See the sapm() notes section for more details.

Returns

effective_irradiance (numeric) – Effective irradiance accounting for reflections and spectral content. [W/m2]

Notes

The SAPM model for effective irradiance 1 translates broadband direct and diffuse irradiance on the plane of array to the irradiance absorbed by a module’s cells.

The model is .. math:

Ee = f_1(AM_a) (E_b f_2(AOI) + f_d E_d)


where $$Ee$$ is effective irradiance (W/m2), $$f_1$$ is a fourth degree polynomial in air mass $$AM_a$$, $$E_b$$ is beam (direct) irradiance on the plane of array, $$E_d$$ is diffuse irradiance on the plane of array, $$f_2$$ is a fifth degree polynomial in the angle of incidence $$AOI$$, and $$f_d$$ is the fraction of diffuse irradiance on the plane of array that is not reflected away.

References

1

D. King et al, “Sandia Photovoltaic Array Performance Model”, SAND2004-3535, Sandia National Laboratories, Albuquerque, NM