Abstract:
In this study, with Constantine station (Algeria) as a case study, five generalized
empirical models taken from the literature correlating the clearness index data with the
sunshine fraction records for estimating the global solar radiation in the first part, and
diffuse fraction data with clearness index records for estimating diffuse solar radiation. The
new regression constants of these ten models were estimated by the curve estimation
technique. Using five statistical parameters, comparison between measured and calculated
values of global and diffuse solar radiation has been performed. According to the results; the
cubic model is found as the most accurate model for the prediction of global and diffuse
solar radiation on a horizontal surface in Constantine in which:
(HG /HO) = 6.616-30.720(s /so)+50.107 (s /so)∂-26.424( s/so)∂
( HD/HG)=1.460-5.326(HG/HO)+9.726(HG/HO)∂-6.736( HG/HO )
Moreover, this model with the new developed coefficients may then be used for locations in
Algeria with similar meteorological and geographical characteristics at which solar data are
not available
