Theoretical Assessment and Validation of Global Horizontal and Direct Normal Solar Irradiance for a Tropical Climate in India

Accurate knowledge about solar radiation in a region is of indispensible significance for sizing,designing and monitoring solar energy systems. In case of inaccessibility to measure solar data, proper solarradiation models may be used. This study aims to present the closeness or the relationship between thepredicted and measured values of global horizontal irradiance and direct normal solar irradiance in a solarmonitoring station located in National Institute of Technology (NIT), Tiruchirappalli. The measured data ispromoted under Indo-German Energy programme by the Ministry of New and Renewable Energy, Centre forwind energy technology and federal of German government named GIZ. The data were monitored for theduration of five months from August 2013 to December 2013. The validation is brought out by the significanceof the regression coefficient, which approaches to unity declaring the fitness of the model resulting inproposing regression models for the considered region. A statistical approach is also carried out for thevalidation by the evaluation of mean bias error (MBE) and the root mean square error (RMSE) from the predictedand the model values. Thus the proposed models lead to theoretical assessment of global horizontal irradianceand direct normal irradiance for a particular location.