Centro de Documentación OLADE -

One of the first problems in the design of flat plate collectors is to decide the amount of energy actually for optimum efficiency. Techniques for calculating the total radiation on cloudless days on inclined surfaces are well known. In practice, however, the problem is to determinate rather the radiation received on surfaces with different orientations under average conditions. The average amount of radiation received can be calculated only for inclined and vertical surfaces, if the diffuse radiation component can be assessed with reasonable accuracy. The paper sets out to provide a rapid method of carrying out such computations which can used by persons relatively unacquainted with either the complexities of the solar radiation climate at different centres or the detailed movements of the sun. It enables the monthly mean daily values of the direct and diffuse radiation to be estimated separately for certain vertical and inclined surfaces using sunshine data.