Optimum Solar Collector's North-South Tilt Angles for Dar es Salaam and their Influence on Energy Collection

Abstract

Solar collectors may receive significantly more solar radiation if some kind of Sun tracking is utilised. Optimal collector tilt angles, however, depend on the geographic location and other parameters including solar insolation for the site. In this study, daily, monthly, biannual and annual optimum tilt angles are calculated using a tilt angle-latitude relation model. The data are then used to obtain monthly and yearly optimum tilt angles through weighted averages considering the yearly fluctuations in solar radiation. The optimum annual tilt angle for Dar es Salaam is found to be 5.3° northwards, whereas biannual tilt angles due south and north are 10.5° and 18.9°, respectively. Analysis on the energy collection by a north-south tracking solar collector revealed an improvement of about 5% with optimum daily and monthly tilting, 4.3% with biannual tilting and about 0.8% with annual tilting, compared to a fixed horizontal collector. The results from this study provide optimal tilt angles for Sun tracking in Dar es Salaam and significant gain in energy collected by the solar collector may be realized through daily, monthly or biannual tracking of the Sun.