Prediction correlations for estimating direct and diffuse solar radiation in Aqaba, Jordan

Abstract EN

The present study develops several correlations for predicting direct, diffuse, and global solar radiation incide'nt on a horizontal surface in Aqaba, Jordan.

The derived correlations for predicting the direct radiation relate the ratios HA/Hg and Hd/Ha with the clearness index (kj = Hi/H0) and the fraction of relative bright sunshine hours, where Hg, Hd, and H0 are monthly mean daily global, direct, and extraterrestrial radiation, respectively.

The prediction correlations for estimating the diffuse radiation express the diffuse fraction of the global radiation and the ratio of diffuse to extraterrestrial radiation as a function of the clearness index and the fraction of sunshine hours.

The present work also derives an empirical equation to determine the monthly mean of daily global radiation from a knowledge of bright sunshine hours.

The correlations developed are shown to be dependent on climatic conditions.

The present work shows good agreement between measured radiation data and predicted values.