A Parabolic Model Presentation of Solar Radiation Data at a Tropical Site, Ile-Ife, Nigeria

Abstract

Monthly average hourly global and diffuse solar radiation at a tropical station, Ile-Ife, Nigeria has been analysed and simple parabolic models established for predicting them. The models appear in the form of parabolic equations with three parameters. The necessary physical interpretations of the model parameters, their temporal variations and implications for the characteristic variation of hourly solar radiation at the station are also presented. Significant relationships between these parameters are also shown. The parabolic model parameters are handy tools for calculating the monthly average hourly global and diffuse solar radiation amounts, the extreme radiation values, i.e. the maximum and minimum and the time of day that extreme values are received on the surface and the diurnal trend of the solar fluxes which are required for solar energy applications. The models can be applicable in any part of the tropics to evaluate the temporal distribution of solar radiation amounts by reassessing the model parameters for the particular site.

Key words: Solar radiation, models, solar energy, conversion