Global solar radiation potential, part 2: Statistical analysis

Solar radiation is the most important parameter in the design and study of solar energy conversion devices. In this regard, many investigators have developed various empirical correlations for the estimation of the solar radiation around the world. The main objective of the present study is to analyze statictically the solar radition models developed in Part 1. In the analysis, the mean percentage error, the mean absolute percentage error, the sum of the squares of relative errors, the relative standard error, the mean bias error, the root square error, and correlation coefficient (R-2) are used used for evaluating the performance of the models studied. It may be concluded that the agreement between measured and estimated values of monthly average daily global solar radiation for the Central Anatolia Region of Turkey along with its twelve provinces is reasonably well.