TY - JOUR
TI - Calculation model for the monthly optimal tilt angle of fixed photovoltaic panels
AU - Zhang Xiang-Xiang
AU - Chen Jia-Long
AU - Dou Hong-Qiang
AU - Liu Cheng-Yu
AU - Hou Xian-Ye
JN - Thermal Science
PY - 2025
VL - 29
IS - 2
SP - 1403
EP - 1409
PT - Article
AB - In photovoltaic systems, the installation tilt angle of modules plays a  critical role in determining both performance and economic returns. Existing  methods for calculating the optimal tilt angle typically rely on complex  solar radiation and anisotropic sky scattering models, which, despite their  accuracy, involve intensive computational efforts. Based on the  relationships between the proportion of direct radiation, latitude, and the  optimal monthly tilt angle, this study proposed a method to calculate the  monthly optimal tilt angle. Taking Zhangye City as an example, the accuracy  and reliability of the proposed method were verified in comparison with the  traditional method. Using this method, the monthly optimal tilt angles were  calculated for three cities in China located at different latitudes, to  reveal the annual variation patterns of these angles. The results showed  that, at the same proportion of direct radiation, the monthly optimal tilt  angle increases with latitude. Over the course of a year, the monthly  optimal tilt angle first decreases and then increases. In low latitude  cites, the monthly optimal tilt angle may even become negative.