Models for obtaining the daily direct, diffuse and global solar radiations

Solar radiation models are desirable for designing solar-energy systems, for good evaluations of thermal environments and for several solar systems in buildings. The purpose of this work is to evaluate four empirical models developed in literature such as Ghouard, Perrin Brichambaut, Bird and Hulstrom and Capderou models. These models can be used to predict the daily direct, diffuse and global solar radiation intensities for clear skies at a given Earth׳s position, in our case, Tetuan city in northern of Morocco (35.57361 latitude, −5.37528 longitude). The statistical analysis was performed by combining simulations through computed values with provided data from local energetic laboratory station. Results obtained show several accuracy levels which indicate that the studied models can be successfully used to predict the daily solar radiation data by days of the year.