ESTIMATION HOURLY GLOBAL RADIATION UNDER CLEAR SKY CONDITIONSIN SOUTHEASTERN ANATOLIA REGION OF TURKEY

Abstract

Growing concern over the world’s increasing energy needs and rapid decreasing reserves of oil, natural gas, and fuel have put in action to develop alternative energy sources. Modern world have increasing population day by day lead to have new energy sources for reply to people’s needs. Solar energy is widely accepted as a crucial energy source for around the world with respect to the environmental concerns associated with fossil fuels as well as their limited reserves. Turkey has a better chance than other countries in terms of solar energy potential because of its geographical situation in the northern hemisphere with latitudes of 36–42 N and longitude of 26–45 E. The annual average sunshine duration of Turkey is 2640 hours. Yearly total radiation intensity per square meter is 1311 kWh. Southeastern Anatolia region has maximum radiation potential and maximum sunlight duration all over the year. The average total solar radiation in annual of Southeastern Anatolia is 1460 kWh/m, maximum sunlight duration is 407 hours in month June and total sunlight duration is 2993 hours. Knowledge of hourly global radiation under the clear atmosphere is important for many solar radiation model. In this study, the models of Haurwitz, Berger and Kasten & Czeplak are tested for hourly global radiation estimation under clear sky conditions for Bozova and Ceylanpinar in Turkey. Solar zenith angle is the focus point for the models. RMSE is used for comparing model results with the measurements. Haurwitz the relative RMSE value for Bozova is 0.00316 and 0.00691 for Ceylanpinar. As a results, it is find that Haurwitz Model performed better than others.