Daily direct, diffuse and global irradiances modelling for an accurate estimate of daily solar radiation intensity at the city of El Jadida (Morocco)

Abstract

In this work, we derive analytic expressions and calculate numerical values of incident daily solar radiation on horizontal, fixed tilted, single-axis and double-axis tracking apertures as functions of day number, collector latitude, tilt and azimuth angles. The effect of non-uniform atmospheric absorption of incident radiation throughout a day is taken into account and new models of direct normal Bn and diffuse horizontal Dh components of global horizontal (tilted) irradiance Gh (Gt ) are proposed, tested and validated on local experimental measurements. This enables us to extract global irradiance model parameters for average day of each month and to predict, accurately, daily solar radiation (energy per unit area) effectively received by any collector placed on earth during the whole year.