Reference / Circumsolar treatment
Model option
Like beam
The ring around the sun is shaded and reflected like the direct beam
Inputs used: Transposition model
Method
After transposition the circumsolar part of the Perez sky, the bright ring around the sun, stays a separate part and goes through the later steps with the direct beam's factors. The horizon profile removes it in the same proportion as the beam, the row shading removes the same fraction of it as of the beam, and the glass reflection uses the incidence-angle modifier at the sun's angle of incidence. This treatment is available with the Perez model only. With the PVsyst 8 Perez settings the ring is zero while the sun is less than 2° above the horizon.
References
- 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.circumsolar = separate