Comparison between different methods for estimation of global radiation over Jeddah

الملخص EN

Solar radiation measurements or estimations are very important in alternative energy studies all over the world.

In subtropics, the importance of this element increased as daily average sunshine duration may reach 10 hours or more.

These areas receive the maximum solar radiation input all over the world.

Many empirical formulae have been used for estimation of solar radiation.

These are relating the total solar radiation at the surface to meteorological elements such as sunshine duration, relative humidity and temperature.

In this study, different empirical and scmi-empirical formulae are examined for the estimation of global radiation in Jeddah under clear sky conditions during February.

March and April in 1986.

1987 and 1988.

It is found that El-Adawi and Goldberg formulae give the best overall estimation of this element during the period of the study.

The differences between the measured and estimated values arc 5 to 10%.

The other formulae give differences in range 15 to 25%