Statistical inter-comparison study of empirical models to estimate the monthly-average daily global irradiation on tilted south oriented surfaces

Abstract

Accurate determinations of the global solar irradiation received by a tilted surface during the average day of each month (HG (s, 0)) are a prerequisite in different solar energy applications, particularly in design methods. Validation of empirical models to estimate such values is of paramount importance, given the limited number of solar radiation observation sites and meteorological stations capable of providing the real information. Using the information of global irradiation on horizontal surface (HG) recommended in the Schedule of Conditions System Technologies of Low Temperature (SCT) for 52 Spanish provinces, four solar irradiation models of estimation were investigated: Liu and Jordan [1], Aláiz [2], Klein [3] and the one proposed by Censolar. A comparative study based on the statisticians of the distribution of the calculated information indicates that the values of HG (s, 0) estimated with the model of Aláiz agreed well with the reference dates. On the contrary, the Censolar model has got the maximum diversion.