Estimation of Hourly Global Solar Radiation in Egypt Using Mathematical Model

The purpose of this paper is to develop a computer mathematical model which produces estimates of the total amount of hourly solar radiation that reaches the earth's surface in a day called hourly global solar irradiance for climate of Delta, Egypt. Predictors for solar radiation have been developed because there is often a lack of representative solar radiation data in most countries. Cloudiness, atmospheric transmissivity, latitude and orientation of the Earth relative to the Sun, time of day, slope and aspect of the surface determine the spatial and temporal distribution of irradiance  incident on a surface. Experimental data were measured in the Solar-Meteorological stations of Agricultural Engineering Department at El-menoufiya University, El-Mansoura university and Belbees. To evaluate the present model a comparison between measured and predicted data has been carried out based on the main bias error and correlation coefficient. It can be concluded that the present model can be used to estimate the values of hourly solar radiation for El-menoufiya El-Mansoura and Belbees.