Study of Solar Radiation in View of Photovoltaic Systems Optimization

The meteorological data concerning solar radiation are generally not sufficient to allow quantifying all the phenomena which occur when a photovoltaic panel receives solar light. It is therefore, necessary to supplement these data by using astronomical calculation for the sun position and modelling the atmosphere. A simple method to calculate global, diffuse and direct irradiance on vertical and tilted surfaces for all uniform sky conditions (clear sky and overcast sky), developed in Constantine (Algeria) and Louvain-la-neuve (Belgium), has been compared with experimental data obtained at Ghardaia (Algeria). In spite of its simplicity, the method furnishes reasonably good predictions, in comparison with experimental data, and can be proposed as a simplified tool for design purposes. This method relies on the fact that we can calculate the irradiance on a plane with arbitrary orientation and inclination, based on the measurement of a single irradiance value on a reference plane.