pvlib.spectrum.spectral_factor_polo#

pvlib.spectrum.spectral_factor_polo(precipitable_water, airmass_absolute, aod500, aoi, pressure, module_type=None, coefficients=None, albedo=0.2)[source]#

Estimate the spectral mismatch for BIPV application in vertical facades.

The model’s authors note that this model could also be applied to vertical bifacial ground-mount systems [1], although it has not been validated in that context.

Parameters:

precipitable_water (numeric) – Atmospheric precipitable water. [cm]
airmass_absolute (numeric) – Absolute (pressure-adjusted) airmass. See airmass_absolute. [unitless]
aod500 (numeric) – Atmospheric aerosol optical depth at 500 nm. [unitless]
aoi (numeric) – Angle of incidence on the vertical surface. See aoi. [degrees]
pressure (numeric) – Atmospheric pressure. See pressure. [Pa]
module_type (str, optional) –
One of the following PV technology strings from [1]:
- 'cdte' - anonymous CdTe module.
- 'monosi' - anonymous monocrystalline silicon module.
- 'cigs' - anonymous copper indium gallium selenide module.
- 'asi' - anonymous amorphous silicon module.
coefficients (array-like, optional) – User-defined coefficients, if not using one of the coefficient sets via the module_type parameter. Must have nine elements. The first six elements correspond to the [p1, p2, p3, p4, b, c] parameters of the SMM model. The last three elements corresponds to the [c1, c2, c3] parameters of the albedo correction factor.
albedo (numeric, default 0.2) – Ground albedo. See albedo. [unitless]

Returns:

modifier (numeric) – spectral mismatch factor (unitless) which is multiplied with broadband irradiance reaching a module’s cells to estimate effective irradiance, i.e., the irradiance that is converted to electrical current.

Notes

The Polo model was developed using only SMM values computed for scenarios when the sun is visible from the module’s surface (i.e., for aoi<90), and no provision was made in [1] for the case of aoi>90. This would create issues in the air mass calculation internal to the model. Following discussion with the model’s author, the pvlib implementation handles aoi>90 by truncating the input aoi to a maximum of 90 degrees.

References