pvlib.irradiance.aoi_projection¶
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pvlib.irradiance.aoi_projection(surface_tilt, surface_azimuth, solar_zenith, solar_azimuth)[source]¶ Calculates the dot product of the sun position unit vector and the surface normal unit vector; in other words, the cosine of the angle of incidence.
Usage note: When the sun is behind the surface the value returned is negative. For many uses negative values must be set to zero.
Input all angles in degrees.
- Parameters
surface_tilt (numeric) – Panel tilt from horizontal.
surface_azimuth (numeric) – Panel azimuth from north.
solar_zenith (numeric) – Solar zenith angle.
solar_azimuth (numeric) – Solar azimuth angle.
- Returns
projection (numeric) – Dot product of panel normal and solar angle.