ANALYSIS OF CONCENTRATION RATIO OF THE PHOTOVOLTAIC SYSTEM WITH ONE TRACKING FLAT MIRROR

Abstract

Solar concentration photovoltaic (CPV) technology is a promising way to increase the conversion efficiency of solar energy. In CPV systems, a large area of sunlight is focused on the smaller area of solar cells with the help of optical light collectors, such as lenses or mirrors. There are different types of CPV systems, among which the simplest is the system consisting of a PV module and a flat plate solar tracking mirror. Due to its simplicity, this CPV system can be successfully applied for building integrated - purpose and hybrid PV and thermal systems.

The output power of CPV systems strongly depends on the concentration ratio of solar rays. To characterize the CPV systems, generally, the geometrical concentration ratio is considered. Meanwhile, the output power of a CPV system depends on the reflectance of mirrors and light transmission into the PV module, which are functions of the light incident angle.

In this paper, an accurate method for analyzing light energy concentration in the CPV system with one tracking flat plate mirror is presented. The proposed method considers both the angular-dependent mirror reflection coefficient and the PV module`s surface absorption properties. The effective concentration ratio is obtained. It is shown that the value of the geometrical concentration ratio is more than the effective concentration ratio. It is also shown that during the analysis of the power output of the concentrating photovoltaic system with one solar tracking flat mirror, the effective concentration ratio must be considered instead of geometric concentration ratio, since the effective concentration ratio, proposed in this paper, can more accurately assess the energy of solar light absorbed by the photovoltaic receiver.