Experimental modeling of the optical and energy performances of a point-focus CPV system applied to a residential user

Abstract

There is not a standard configuration of Concentrating Photovoltaic (CPV) systems on the market because it must be defined according the user characteristics. Hence, it is important to evaluate the real optical and energy performances of CPV system to satisfy accurately the user energy demands. An experimental model able to calculate energy and optical performances of CPV system with Triple-Junction (TJ) cells, is presented in this paper. First, optical performances influencing the CPV system electrical producibility, are evaluated. Optical concentration factor (Copt) and optical efficiency are experimentally determined in terms of distance between TJ cell and optics. Successively, a black-box model able to link simultaneously TJ cell electrical power with Direct Normal Irradiation (DNI) and TJ cell temperature when Copt varies, is adopted; it is difficult to link these variables by means of a white-box model. This link is basic to evaluate the real CPV system performances when it is sized to match the user energy loads. Hence, the CPV system feasibility applied to 120 m2 residential user, is evaluated. The modules optimal number is defined to maximize the investment profitability. The modules optimal number is five with a Net Present Value equal to 7.2 k€.