Model step
Circumsolar treatment
How circumsolar diffuse irradiance is applied
Inputs used: Transposition model
What it is
The sky is brightest in a ring around the sun. That circumsolar light behaves almost like the direct beam: a shadow blocks it and the glass reflects it at the same angle. This step decides whether the model treats it like the beam or like the rest of the sky light.
Options
- Like beam: the ring around the sun is shaded and reflected like the direct beam
- As diffuse: the ring around the sun is treated as sky light
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 | diffuse