Optimal tilt angle and orientation for solar collectors in Iran

The variation of tilt angle changes the amount of solar radiation that reaches to the surface of the collector. Hence, tilt angle is an important factor that affects the performance of a solar collector. In this study, a mathematical model is proposed for estimating the solar radiation on a tilted surface, which determines the optimum tilt angle of solar collector and its orientation (surface azimuth angle) in a specific period of time during a clear day, in some big cities of Iran. The optimum angles are calculated using GSA for the values of which the radiation on the collector surface is at the maximum level for different circumstances of the environment. The results reveal that setting the tilt angle and surface azimuth angle are necessary in order to reach to the maximum radiation in clear days when cos 9 = 1 and angle of incidence would be zero.