Optimization of solar panel tilt angles by isotropic and anisotropic models for Turkey

The energy resources used in the world may be insufficient in many aspects such as economic changes and living conditions in the development of countries. The popularity of renewable energy sources is increasing with the increase in the problems arising from the use of non-renewable energy sources. Solar energy plays a significant role in meeting the worldwide energy supply as a clean, reliable and accessible energy source. Achieving maximum gain from solar panels, which form the basis of solar energy, depends on geographic location, solar energy model applied and obtaining accurate data. Determining the tilt angle of the panels provides maximum efficiency from solar energy. In this study, monthly, annual and seasonal optimum tilt angles for all provinces of Turkey were obtained by using 12 isotropic and anisotropic solar radiation models. The data in the calculations are taken from satellite-based sources for the period from the beginning of 2001 to the end of 2020. In order to examine the accuracy of solar radiation models, monthly, seasonal and annual values of tilt angles were investigated. It has been observed that the optimum mean annual tilt angle obtained by using different radiation models varies between 28° and 48°. When the seasonal mean optimum tilt angles are analyzed, it is observed that the optimum tilt angles for summer and spring seasons mostly vary between 20°-25°, 39°-53° for autumn and 46°-72° for winter. As a result of the analysis made with the real field data taken for the province of Izmir, it can be concluded that the Perez model is a suitable model for İzmir. The optimum panel inclination angles obtained in this thesis study are expected to be a literature study that guides the panel optimization for 81 provinces in Turkey, while obtaining the maximum efficiency. Keywords: optimization, optimum tilt angle, solar energy, radiation, isotropic model, anisotropic model