Estimation of Global Solar Radiation from Temperature Extremes: A Case Study of Hebron City, Palestine

Abstract

Solar radiation is the main energy source for mankind and an accurate data of solar radiation levels for a particular location is vital for the optimum operation of solar energy transducers such as photovoltaic cells and solar thermal collectors. This study aimed to calibrate some of the existing models in the literature for estimating daily global solar radiation parameter using available measured records of air temperature extremes and new models were developed based on maximum and minimum air temperatures. Applicability of the Hargreaves model, Allen model, Bristow-Campbell model and Chen et al. model were evaluated for computing the global solar radiation for Hebron city in Palestine. Estimated values were compared with measured values in terms of the coefficient of determination (R 2 ) and root mean square error (RMSE). All models provide good estimates when compared to the accurate values with R 2 0.9226 (Bristow-Campbell model) to 0.9547 (Chen et al. model), while the proposed model provides a value of 0.9632. The RMSE value ranges from 0.7632 for Chen et al. model to 0.9211 for Bristow-Campbell model, however a lower value (0.7118) for the proposed model. This study found that the proposed model estimates global solar radiation at the location of study better than the other models.