Estimation of monthly average daily global solar radiation - case study: Coimbatore, India
In the present work, global solar radiation for the month of March and April 2018 using theoretical regression models, which were proposed by literatures were estimated. The comparison was made between measured and estimated global solar radiation for south region of India in south western of Tamilnadu in the city of Coimbatore (Latitude 11.01o N). The estimation of monthly average daily global solar radiation on a horizontal surface was calculated through six theoretical regression models such as Modified Angstrom, Benson et al, H.P.Garg & S.N.Garg, Behal et al, Luhanga & Andringa and Veeran & Kumar. The estimated global solar radiations from various models were evaluated by the statistical parameter tests such as Mean bias error, Root mean square error, Mean percentage error and Standard deviation. It was found that the Benson et al model gives better results in the month of March and model had the smallest values (MJ/m2/day) of MBE, RMSE, MPE and SD of 0.85, 4.72, 0.17 and 4.64 respectively. Similarly, Behal et al model gives good results on April, had the smallest values of MBE, RMSE, MPE and SD of 0.31, 1.40, 0.10 and 1.37 respectively.
Keywords - Coimbatore, Estimation, Regression models, solar radiation, Statistical parameters.