A quantitative review and classification of empirical models for predicting global solar radiation in West Africa

Abstract

The knowledge of the global solar radiation is of particular significance in reliable evaluation of the solar energy potential in a given locality. However, ground measurement of global solar radiation (GSR) is not available in most locations in West Africa. During the past 36years in order to estimate GSR on the horizontal surface on both daily and monthly mean daily basis, several empirical models have been developed for numerous locations in West Africa. As a result, various input parameters have been utilized and numerous functional forms employed. In this study aimed at classifying and reviewing the empirical models employed for estimating GSR in West Africa, the empirical models so far utilized were classified into six main categories and presented based on the input parameters employed. The models were further reclassified into numerous main sub-classes (groups) and finally presented according to their developing year. On the whole, 356 empirical models and 68 functional forms were reported in literature for estimating GSR in West Africa. The authors equally compared the empirical and soft computing models for estimating GSR in West Africa and across the globe and observed that the soft computer models yielded better. Thus, this review would provide solar energy researchers in terms of identifying the input parameters and functional forms widely employed up till now as well as recognizing their importance for estimating GSR in several locations and need to adopt soft computing methods particularly promising as an alternative approach for estimate GSR with high precision in West Africa.