An anisotropic model for diffuse radiation incident on slopes of different orientations and possible applications to CPC's

Abstract

Based on a simple description of the sky dome, a model for estimating diffuse on sloping surfaces, once knowing this value on the horizontal, is developed. Its parameters are established from the analysis of solar radiation data on seven sloping sensors. Tests against data show that substantial improvement is achieved over the isotropic model for any collector slope or orientation. The simple geometry of the model offers the possibility of applications to collectors with limited fields of view such as CPC's.