Performance Evaluation of a Mixed-Mode Solar Dryer

Abstract

This paper presents the design, construction and performance evaluation of a ‎mixed-mode solar dryer for food preservation. In the dryer, the heated air from a ‎separate solar collector is passed through a grain bed, and at the same time, the drying ‎cabinet absorbs solar energy directly through the transparent walls and roof. The results ‎obtained during the test period revealed that the temperatures inside the dryer and solar ‎collector were much higher than the ambient temperature during most hours of the day-‎light. The temperature rise inside the drying cabinet was up to 74% for about three hours ‎immediately after 12.00h (noon). The drying rate and system efficiency were 0.62 kg/h ‎and 57.5% respectively. The rapid rate of drying in the dryer reveals its ability to dry ‎food items reasonably rapidly to a safe moisture level‎