Prediction of daily solar radiation intensity by day of the year in twenty-four cities of Morocco

In this study, by using the acquired data from Meteonorm, we used two empirical models developed in literature to predict direct, diffuse and global solar radiation fluxes. Solar radiation intensity of Agadir, Al Hoceima, Beni Mellal, Casablanca, Er-Rachidia, Essaouira, Fes, Ifran, Kenitra, Larache, Marrakech, Meknes, Melilla, Nador, Ouarzazate, Oujda, Rabat, Safi, Sidi Ifni, Tangier, Taza, Midelt, Tetuan and El Aaiun cities is predicted. In order to evaluate the day by day performance of these models, a statistical analysis was performed by using several statistical indicators of mean absolute bias error, root mean square error, normal root mean square error, test statistic, standard deviation and coefficient of determination. The results obtained are acceptable and they gave a good approximation between the estimated and the measured values. The daily solar radiation intensities predicted in this study can be used in the design and estimation of the solar system performance in all Moroccan cities and in other locations of similar climate conditions.