Reference / Circumsolar treatment
Model option
As diffuse
The ring around the sun is treated as sky light
Inputs used: Transposition model
Method
Right after transposition the circumsolar part, the bright ring around the sun, is added to the uniform sky light. From then on it is sky light: the horizon profile reduces it with the rest of the sky light, the rows mask it with the sky-masking factor, and the glass reflection uses the diffuse incidence-angle factor. With the Hay–Davies and isotropic models this is the only treatment. The Hay–Davies circumsolar part, projected with the direction of the sun, is added to the sky light after transposition in the same way; the isotropic model has no ring.
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 = diffuse