Energy loss of photovoltaic system caused by irradiance and incident angle

Recently, installation of PV systems is rapidly spread. It is necessary to establish a diagnostic method of PV systems. The authors are studying the influence of irradiance and incident angle on the energy loss of PV module. In this paper, the power loss of PV module caused by the loss factors such as intensity of irradiance and incident angles related to direct and diffuse irradiance, are estimated from the empirical formula. The changes of the power loss of PV module caused by the loss factors are described in a day and season. It found that the total loss rates of PV modules installed in the south at 35 degree of tilt angle and in the east and the west at 90 degree of tilt angle are about 4-8% and 10-17%, respectively.