Daily utilizability from hourly cumulative frequency curves

This paper describes a simple method of estimating daily utilizability (Φ) on a horizontal surface at Madras and Kodaikanal (two locations in South India). The daily utilizability has been derived from the cumulative frequency curves of IIm using five years of hourly global radiation data on a horizontal surface. The results of the analysis have been compared with data and the results of Klein at these two locations, in terms of standard deviation and relative standard deviation. The results show that the proposed method is easy to use and is more accurate than Klein's method.