期刊名称：International Journal of Energy and Environment
印刷版ISSN：2076-2895
电子版ISSN：2076-2909
出版年度：2010
卷号：1
期号：5
页码：833-840
出版社：International Energy and Environment Foundation (IEEF)
摘要：The time dependent monthly mean hourly diffuse solar radiation on a horizontal surface has been estimated for Lucknow (latitude26.75 degree, longitude 80.50 degree) using least squares regression analysis. The monthly and annually regression constants are obtained. The present results are compared with the estimation of Orgill-Holands (Sol. Energy, 19 (4), 357 (1977)), Erbs et. al (Sol. Energy 28 (4), 293-304(1982)) and Spencer (Sol. Energy 29 (1), 19-32(1982)) as well as with experimental value. The proposed constant provides better estimation for the entire year over others. Spencer, who correlate hourly diffuse fraction with clearness index, estimates lowest value except in summers when insolation in this region is very high. The accuracy of the regression constants are also checked with statistical tests of root mean square error (RMSE), mean bias error (MBE) and t –statistic tests.
