Solar radiation on variously oriented sloping surfaces

Abstract

Monthly average daily irradiation on surfaces tilted towards the equator and also inclined at various azimuth angles are estimated for two locations in Lesotho and the results are presented. The isotropic model suggested by Liu and Jordan (Trans. of Ashrae, 526, 1962) along with the modified equation of Klein (Solar Energy, 19, 4, 1977) are employed for the estimation purposes. Surface orientations are selected at three inclinations for six different azimuth angles. Conclusions are reached for optimum tilt and orientation for summer, winter and annual collection. Total annual radiation values are computed for all the slopes and orientations. © 1991.