API field
Transposition model
How horizontal sunlight is converted to sunlight on the tilted plane
What it is
Selects the model that converts the horizontal irradiance of the weather file into the irradiance on the tilted plane.
Typical values and how to get it
Chosen on the Model tab.
Values
Perez 1990 = perez (default): splits the sky diffuse into a uniform dome, a circumsolar region and a horizon band with empirical coefficients · Hay–Davies = hay_davies: splits it into a circumsolar part weighted by the anisotropy index (the direct normal over the extraterrestrial irradiance) and a uniform remainder · Isotropic = isotropic: treats the sky as uniform
References
- Perez, Ineichen, Seals, Michalsky & Stewart 1990, Modeling daylight availability and irradiance components from direct and global irradiance, Solar Energy 44(5) 271–289
- Hay & Davies 1980, Calculation of the solar radiation incident on an inclined surface, Proceedings of the First Canadian Solar Radiation Data Workshop, 59–72
- Liu & Jordan 1963, The long-term average performance of flat-plate solar-energy collectors, Solar Energy 7(2) 53–74
API
array.transposition_model