Testing the Refractance window dryer with different sources of Biomass energy using sweet potatoes.

Abstract

The hybrid RWD was designed and fabricated by Makerere University under the Bio innovate Africa program. The dryer can be powered by either electricity or biomass, it has a mylar tray onto which the food is placed. During the process of refractance window drying, thermal energy from a shallow trough of hot water is transferred to wet material, normally in form of pulp, juice or slices. Infrared radiations from the hot water are transmitted to the food through the film such as mylar thus causing rapid drying, which consumes a lot of electricity during the process. The main aim of this project is to test the performance of the hybrid RWD with major emphasis on its operation using different biomass sources like firewood, charcoal, briquettes and on the quality and uniformity of drying sweet potatoes. It was found that maize cobs are the most efficient biomass source to power the machine followed by firewood and lastly charcoal.