The Development of a Photovoltaic Powered Forced Convection Solar Maize Dryer for Use In Sub-Saharan Africa

Abstract

This solar crop dryer dries 90 kg amounts of maize, as on small farms in east and central Africa, from about 33.3 % moisture content dry basis to 14.3 % dry basis (d.b.) for storage in one day of clear weather conditions and is equal to less time than open air sun drying. The dryer has been developed through several stages of postgraduate research, laboratory and field development and analytical modeling. Passive temperature control is a major aspect of the design, so the grain is not heated above 60  /span>C. The solar, thermal and electrical characteristics of dryer were measured under a solar simulator in Scotland and under field conditions in Malawi. A collector thermal efficiency of 80 % and drying efficiency of 58 % were obtained for dryer. The principles in improving efficiency in the present design include a solar air collector that can be optimum drying rate and passive temperature control to 60 grain temperature. A financial analysis showed that the dryer technology is viable with a payback period under 3 years.