Global, Diffuse Sky And Direct Beam Radiation Data For Kumasi, Central Ghana

Abstract

The two components of global irradiation namely, direct beam and diffuse sky irradiations were measured with a Li-Cor photovoltaic pyranometer model LI-200SA over a four year period between 2001 and 2005 in Kumasi, located in the central part of
Ghana (6° 40\'N, 1° 34\'W). Analysis of the results shows that the highest monthly average hourly global irradiance over the period (740.84 W/m ) and peak average hourly direct beam irradiance of 439.18 W/m were recorded in April. The highest peak monthly
average hourly diffuse irradiance (521.72 W/m ) was in June. Monthly average daily direct beam irradiation and global irradiation range between 2563.09 Wh/m -day and 414.4 Wh/m -day and 4996.3 Wh/m -day and 3059 Wh/m -day respectively. The highest
global irradiation occurred in April and the lowest occurred in August. The high level of diffuse sky irradiation in Kumasi has been attributed to the influence of atmospheric effects including the presence of rain cloud cover during the wet season and the presence
of the Harmattan dust aerosol during the dry season.

Keywords: Global irradiance, diffuse sky irradiance, direct beam irradiance, weather

Journal of the Ghana Institution of Engineers Vol. 5 (1&2) 2007: pp. 49-60