Perez settings

What it is

Selects the constants and inputs of the Perez transposition model. It has no effect unless the transposition model is Perez.

Typical values and how to get it

Chosen on the Model tab.

Values

PVsyst 8 settings = pvsyst_8 (default): the direct light from the global minus the diffuse, a solar constant of 1361 W/m², the Kasten 1966 air mass, the beam clearness capped at 0.9, and no floor on the circumsolar term · Published settings = published: the file's direct normal irradiance, 1367 W/m², the Kasten–Young 1989 air mass, no clearness cap and a circumsolar term held at 0 or above · NREL SSC settings = ssc: the file's direct normal irradiance, 1367 W/m² with no yearly variation, the Kasten 1966 air mass, a circumsolar term held at 0 or above, and a uniform sky when the sun is within 2.5° of the horizon

References

1. Perez, Ineichen, Seals, Michalsky & Stewart 1990, Modeling daylight availability and irradiance components from direct and global irradiance, Solar Energy 44(5) 271–289

API

array.perez_settings