Estimation of global solar radition sunshine duration for M´sila region (Algeria)

Information of local solar radiation is essential for many application as solar energy systems (solar heating, photovoltaic). For this purpose, several empirical correlations have been developed in order to estimate solar radiation around the word. There are a number of formulate which relate global radiation to other climatic parameters such as sunshine hours, maximum temperature and relative humidity. The most important parameter for estimating global radiation is sunshine duration. The global solar radiation and sunshine hour duration measured over a period of four years (2002-2005) for M´sila region in Algeria (latitude: 35° 42´ N, longitude 4° 32´ and altitude of 441 m above the sea) were used in this study. Based on Angstrom model monthly and annually regression constants for this region was developed and calculated using three sunshine based models; linear, quadratic and exponential equations. Comparing these models it was observed that the quadratic equation model performed better in terms of coefficient of determination than the other models. Finally, a comparison between quadratic monthly model and quadratic annually model for estimating average global solar radiation was performed using statistical test methods such as R2 and RMSE. The agreement between the measured and monthly model was remarkable and this model is recommended for use in M´sila region.