Estimation of Global Solar Radiation on Horizontal Surface from Sun Shine Hours and Temperature at Kombolcha, Amhara Region, Ethiopia

Abstract

The detailed knowledge of the local solar radiation is important but, measuring instruments are not readily available in many places, particularly in Ethiopia. Therefore, this work focused on the application of climate data to compare sunshine and temperature based empirical equation of the global solar radiation in Kombolcha sites, Amhara region, Ethiopia. For data obtained in a period of 2008 to 2017 from the Kombolcha meteorological agency correlations be tested for errors using: Mean Bias error (MBE), Root Mean Square Error (RMSE), Mean Percentage Error (MPE), and correlation Coefficient (r). The latest computing MATLAB soft ware and excel spread sheet has been used for the entire analysis. The empirical equation having the least error was selected for Kombolcha sites. Therefore, according to accuracy the Hargreaves and Samani empirical equation is suitable for Kombolcha sites than Angstrom-Prescott empirical equation. The abundant average global solar radiation of 6.19 KWh/m 2 /day and 7.09 KWh/m 2 /day was estimated using sun shine and temperature based empirical equation respectively. This result showed that there is good solar potential in Kombolcha, Amhara region, Ethiopia.