Predicting beam and diffuse horizontal irradiance using Fourier expansions

A new method for obtaining very accurate models to predict the Beam and Diffuse Horizontal Irradiance is proposed, using two sources of data: satellite irradiation estimations and two clear-sky models (one for Beam and one for Diffuse Irradiance). By means of a Fourier Series approximation, we correct the clear-sky models and adapt them to the climatological conditions of a specific location. Applying it to six cities in latitudes ranging from 36 degrees to 60 degrees degrees North, we compare our predictions with real ground-level data obtained (in this work) from the WRDC database. Results show that the proposed model is both accurate and applicable to different climates. (C) 2020 Elsevier Ltd. All rights reserved.