Correlations for Predicting Average Global Solar Radiation Incident on a Horizontal Surface in Amman, Jordan

Abstract

The present work develops several empirical formulas for estimating the average hourly, daily and monthly global solar radiation incident on a horizontal plane in Amman, Jordan. The developed formulas correspond to sinusoidal correlations which express the values of the total solar radiation available in terms of the hour, day and month of the year. The determined coefficients of the sinusoidal correlations are expressed in polynomial form in terms of the hour and month of the year to allow the use of a single formula for determining the hourly and monthly variations of solar radiation in Jordan. The present correlations are based on hourly measurements of solar radiation over the period (1983-1987) and are considered suitable for solar energy collection applications. The computed solar radiation values, using the present correlations, were compared with measured data. The results obtained indicate that the overall mean error ranges from 0.2 to 9.5%.