Determination of optimum tilt angles for solar collectors in low-latitude tropical region

This work optimises the collection of solar energy within the period of its availability in order to increase its utilisation and also to enhance performance of heating systems that depend on it through appropriate determination of optimum solar collector tilt angles. Buoyancy-induced flow equation in solar collector pipe was established by continuity, energy and Navier–Stokes equations in cylindrical coordinates. Fundamental solar radiation equations were programmed to determine optimum tilt angles in locations within latitudes 1° and 14°. A set of data recorded from a pryanometer located on latitude 6.45° north of the equator was used to generate average monthly radiation over the latitudes. Graphs obtained from latitude 6° and 13° data were analysed to investigate solar radiation on some tilt angles. The optimum tilt angles for solar heating for periodic tracking of the sun in the region within latitudes 1° and 14° were predicted as phi+ 25° for November, December and January; phi+ 15° for February, September and October; phi + 15° for August; phi+ 25° for May, June and July; and phi for March and April. The results of this work confirmed that solar radiation on tilted surface increases with latitude.