Sunshine Duration-Based Models for Predicting Global Solar Radiation

Abstract

Measured solar radiation data are the best source for proper knowledge of global solar radiation. However, it is not possible to measure global solar radiation in many areas due to cost and maintenance of the measuring equipment. At this point, the relationship between global solar radiation and sunshine duration plays an important role. This paper presents a new model, as well as eight models which presented in the literature for estimating global solar radiation on the horizontal surface using only sunshine duration. This new model is called reverse model. The estimation of global solar radiation is based on measured global horizontal irradiance data collected in Tripoli (lat. , long. ), Libya during 2015 and measured every 1 minute. The performance of the models is evaluated using statistical error tests. The results show that the linear and reverse models presented favourable efficiency, and logarithmic model showed the least accurate model.