Determination of Optimum Tilt Angle for Flat-Plate Solar Collectors and Photovoltaic Panels in Khuzestan Province

 Solar collectors and photovoltaic panels are usually exposed to the sun at a fixed angle relative to the horizon. The optimal angle has a significant effect on receiving maximum energy. Since there is not a comprehensive study to determine the optimal angle in Khuzestan province, in this research, the centers of counties in Khuzestan province, including twenty-six cities, were considered. The energy received on an inclined surface was calculated based on the average of 16 years of solar radiation data and the isotropic and non-isotropic models (HDKR model). Different angles from -20 to 90 degrees with a step of 0.1 were examined using Fortran codes, and the angle corresponding to the maximum received energy was determined as an optimal angle. Comparing the obtained results with previous studies showed that the HDKR model has better performance, and the average optimal angle of the cities of Khuzestan province was approximately 26 degrees with a standard deviation of 0.8 degrees.