Computation of Incident Solar Energy

Computations of the daily and annual totals of the solar energy incident upon south-facing tilted flat surfaces were carried out for several cloudfree atmospheric models after taking into account, somewhat arbitrarily, the contribution due to sky radiation and that due to radiation reflected by the ground. Representative variations of these quantities are discussed as a function of several parameters such as geographical latitude of the location, tilt angle of the surface, atmospheric transmission characteristics, sky-radiation contribution, and ground reflectivity.