The Applicability of Several Diffuse Solar Radiation Models to the Cypriote Environment

Abstract

Solar radiation measurements at one location in Cyprus are used to test the applicability of several theoretical and empirical models which compute diffuse radiation on a horizontal surface. Two types of correlation tests were used [I]: the first correlates the ratio of diffuse-to-global solar radiation with the "clearness index" 6; and the second correlates the ratio of diffuse-to-global solar radiation with the fractional sunshine.Therefore, the selected models for discussion are compared and tested for their applicability to one location in the eastern Mediterranean basin in general, on the basis of statistical error tests. A comparative study of the models shows that Page's model [3], based on the first type of correlations and Hay's one [13] based on the second type of correlations, are equally accurate for the greater Cypriote environment. Finally,' two statistical equations are proposed for estimating diffuse radiation for solar energy applications in the greater environment of Cyprus.