New Models for Estimation of Solar Radiation for Five Cities of Pakistan

The increasing demand for electricity due to the ordinary person's lifestyle has put immense pressure on fossil fuels. The rapid depletion of fossil fuels has made scientists and engineers search and adopt alternative sources of energy. Renewable energies, e.g., wind, hydro, biogas, solar, etc., are an excellent alternative to conventional energy sources. In this paper, we developed three models for direct beam solar radiation (BSR), diffuse solar radiation (DSR), and global solar radiation (GSR) for five cities (Karachi, Hyderabad, Lahore, Quetta, and Peshawar) of Pakistan. In these models, BSR, DSR, and GSR are given as a function of day-number. Three types of solar radiations have been calculated through the models developed in this study. The results are compared with the corresponding values calculated by the standard clear sky ASHRAE model. A good agreement is found between these values. For validation of results, Root means square error (RMSE), Mean Absolute error (MABE), Mean Absolute percent error (MAPE), and chi-square (χ2), and coefficient of determination are calculated and found to be in the accepted range. It has also been found that DSR, BSR, and GSR have an inverse relation with Latitude.