Estimation of Solar Radiation of Khartoum City Using ASHRAE Model

Abstract

As Sudan is a tropical country with high solar radiation, solar energy seems to be attractive source of energy. To study the feasibility of solar energy in a region, information on the intensity of solar radiation in addition to the values of direct and diffuse radiations are required. Therefore, this paper aims to estimate the solar radiation of Khartoum city, Sudan. The diffuse, direct and total solar radiations were calculated theoretically using ASHRAE model. The results showed that the solar radiation begins to rise from morning hours reaching highest value at the noon time and gradually reduces until sunset time. The direct radiation was higher than the diffuse radiation except during morning and evening hours of the day. The results also showed that the peak value of solar radiation reaching the earth surface happens during midday very close to noon time. The peak values of total solar radiation happen during summer seasons while lower values happen during winter seasons. The maximum daily average solar irradiance was 8560$\text{W/m}^{2}$ on May and minimum daily average solar irradiance was 4481/$\text{W/m}^{2}$ on December. The location of Sudan is good for thermal solar application because of the average daily beam irradiance which is about 5231/$\text{W/m}^{2}$.