Estimation of optimal tilt angles and solar radiation collected by fixed and tracking solar panels for the Mediterranean region, Turkey

The correct determination of the optimal tilt angle is one of the crucial criteria to collect the maximal amount of solar radiation by solar-power systems, as it could vary significantly by the geographical location. In this study, a numerical method is proposed to determine the optimal tilt angle of fixed solar panels, then this value is used to investigate the maximal solar radiation collected by the optimally fixed panels. The method is extended to one-axis and two-axis tracking systems to maximize the collected solar radiation and then obtained radiation values of the tracking systems are compared to a fixed system. Thus, this study presents the proper determination of the tilt angle to maximize the solar energy collected by the tilted solar panels by using the proposed method. Specifically, this study presents the radiation gains of solar trackers for which optimal tilt angles should be set precisely to improve efficiency and the amount of solar radiation on either tracking or tilted panels across the Mediterranean region. It is found that the annual optimal tilt angle range is 29°-33°, and the optimally tilted panels gain from 9.33 to 12.90% more daily solar radiation compared to non-tilted panels in the Mediterranean provinces of Turkey. It is also found that a one-axis tracking system harvests between 28.48 and 33.09% of daily solar radiation, whereas a two-axis tracking system harvests between 32.41 and 37.12% of daily solar radiation when compared to the fixed system under the same conditions. The methodology can be implemented in other provinces of Turkey and even extended to any place in the world. (author)