ESTIMATION OF SOLAR RADIATION: AN EMPIRICAL MODEL FOR BANGLADESH

This study is carried out to compute empirically global, diffuse and direct solar radiation on a horizontal surface for the ten districts equally distributed all over Bangladesh (20o34΄and 26o34΄north latitude, 88o01΄ and 92o41΄east longitude) as well as to predict correlations among them. For this study, meteorological data for 28 years (between 1980 and 2007) are used which are collected from Bangladesh Meteorological Department. The global radiation in Bangladesh is found to be maximum in the month of April/May and minimum in the month of November/December in all the districts. The values of the correlation coefficients a, b, c, d, c , d , e, f, e and f for ten stations of Bangladesh are also evaluated. It is evident that, the values of the coefficient “a” vary from 0.2296 to 0.2569, while the coefficient “b” varies from 0.5112 to 0.5560. The overall mean deviations of the ten values of both a and b are 0.2432±0.0136 and 0.5336±0.0224, respectively. The maximum and minimum values of the other correlation coefficients c, d, c , d , e, f, e and f are (1.5695 and 1.4357), (-1.7210 and - 1.9986), (0.4011 and 0.376), (-0.2072 and -0.2510), (-0.3811 and -0.5464), (1.946 and 1.6456), (-0.1206 and -0.1684) and (0.7984 and 0.7000) respectively. Their maximum variations due to location are (1.5022±0.0672), (-1.8598±0.1388), (0.3885±0.0125), (- 0.2291±0.0219), (-0.4637±0.0826), (1.7958±0.1502), (-0.1445±0.0239) and (0.7492±0.0492) respectively.