Research on Optimum Tilt Angle for PV Array and Global Solar Radiation on Inclined Surfaces in Zhejiang Province

Based on sunshine hours, global radiation observational data and scattered radiation data in Zhejiang Province during 1993-2021, we utilize Angstrom-Prescott model and tilt radiation model to calculate the global solar radiation on optimum tilt angle and on horizontal plane at different stations and to analyze the differences in spatial distribution characteristics.The results show that the annual average global solar radiation on horizontal plane in Zhejiang Province ranges between 4500 and 4910 MJ·m^-2.The optimum tilt angle for PV array is 23°~27°in Zhejiang Province.And the annual average global solar radiation on optimum inclined surfaces reachs 4749~5365 MJ·m^-2, which exhibits a decreasing tendency from the northeast to the southwest.The higher value is identified around Hangzhou Bay and in Zhoushan coastal areas, and the lower value is in the mountain area of southwestern Zhejiang.The global solar radiation on optimum inclined surfaces is significantly enhanced than that on horizontal planes, with the increase of 240~460 MJ·m^-2 (5.3%~9.4%).The increase is more prominent in the north of Zhejiang, with the increment over 360 MJ·m^-2 (7.7%), while the increase is relatively small in the south of Zhejiang, lower than 280 MJ·m^-2 (6.2%).