Journal of Emerging Trends in Engineering and Applied Sciences: Research Areas

Abstract:
This study presents and evaluates the behaviour of three empirical models based on the difference between maximum and minimum temperatures at Ibadan (7o 22�N, 3o 53�E). This was done by using monthly data on solar radiation and minimum and maximum temperature for a period of 6 years, (2001 � 2006). The corresponding monthly value of extraterrestrial solar radiation (Ra) was calculated for each data. Forecasting performance parameters such as coefficient of determination (r2), root mean square error (RMSE), mean bias error (MBE) and mean absolute percentage error (MPE) are presented as analyzed for the models. The Hargreaves model with linear regression has the highest r2 value of 0.72 and lowest RMSE, MBE, and MPE values of 1.59 MJm-2day-1, 0.82 MJm-2day-1 and -7.36% respectively. The best performance for the present data set was found at Hargreaves model with linear regression, and followed by Hargreaves model with power regression and original Hargreaves model. The present result suggested the Hargreaves model with linear regression reasonably predictable global solar radiation and the expected solar radiation behaviour in the area of study.

Keywords: solar energy, solar radiation, temperature, empirical models, extraterrestrial radiation

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