Analysis and optimization of tilt angle for photovoltaic arrays

In this paper, a mathematical model is established by C language programming. The model is based on the KT method of calculating the average solar radiation on sloped surfaces which shows improved results over the isotropic method. The average solar radiation at different locations of China are calculated and compared with the results gained in previous research or by widely used commercial software for validation. The good agreement indicates that the model is suitable for calculating the amount of solar radiation and determining the optimum tilt angle. The monthly, seasonal and yearly optimum tilt angles are determined according to the monthly, seasonal and yearly maximum radiation respectively when the tilt angle changes. A new adjustment of changing seasonal tilt angle is presented. The solar radiation falling on the tilted surface is found to be enhanced as new seasonal adjustment is adopted. The results show the influence of tilt angle on the performance of photovoltaic projects.