Radiation on Inclined Planes

The Perez model (Perez et al. 1986) enables global and diffuse radiation to be calcu­lated on an inclined surface using two input values, hourly global horizontal and dif­fuse horizontal irradiance. Additionally models from Hay (1978), Gueymard (1987) and Skartveit and Olseth (1986) are included. Hay’s model distinguishes from the 3 other models by it’s simple structure and the small number of input values.

As input for the calculation global radiation, diffuse radiation and albedo is needed.



Fig. 15.6 Cumulative distri­bution functions of hourly beam irradiance for Boulder (CO, USA)