Assessing the distribution of monthly mean hourly solar irradiation at an African Equatorial site

Existing literature lacks information on the distribution of total solar radiation and its components for locations within the Equatorial region. Locations in this region have substantial amounts of the solar energy resource. Distributions of solar radiation can provide a convenient format for reading solar radiation data. This data is required by modelers of solar energy applications. The objective of this study is to draw and assess the distributions of the monthly means of hourly total, diffuse and direct solar irradiation at a selected site in the Equatorial region. A location at latitude 02°17′N, longitude 32°56′E and altitude 1189 m, was selected for this study. The results have shown the distribution of global solar irradiation to have the highest peak of 4.0 MJ/m2 in December and peaks of 3.0 MJ/m2 throughout the year. A four peaked diffuse solar irradiation distribution was evident where the highest diffuse peak of 1.8 MJ/m2 was observed in September. The distribution of the direct solar irradiation exhibited peaks of 2.0 MJ/m2 during the first and last quarters of the year.