A Comparative study of different solar irradiation models to determine the optimum tilt angle of solar collectors in Yazd, Iran

In this paper different diffuse models were used to determine the optimum tilt angle of solar collectors in order to collect the maximum solar irradiation. Thecollector surface is assumed to be facing toward equator. The optimum angle was computed by searching for the values for which the total radiation on thecollector surface is a maximum for a particular day or a specific period. The accuracies of the models were compared in terms of the statistical indicators, RSMEand MBE. The results showed that the Klucher model gives the best results. An application of the models is done using the experimental data measured for Yazd in Iran. The results indicated that the optimal angle of tilt ( opt ) for each month, allows us to collect themaximum solar energy. Annual optimum tilt angle is found to be approximately equal to latitude of the location. It was shown that the loss in the amount ofcollected energy when using the yearly optimum tilt angle was around 10.39% compared to the monthly optimum tilt opt(m) .

Keywords:

solar collector , solar energy , optimum tilt angle , isotropic models , anisotropic models