On the development of solar drying system

Abstract

In the present work, solar thermal drying system was developed. The main purpose of solar thermal drying system is to dry local vegetables and fruits. The drying system contained of two main parts as heat collector and the food drying cabinet. It is a force convection indirect type absorbing maximum solar radiation by the heat collector and provides heated air flow to the cabinet via two fans at the air inlet/outlet. The heat collector was inclined at 23.5 angle which suitable to the location for absorption of maximum solar radiation. Experiments were performed to test the efficiency of the solar heat collector and the cabinet at different daily times and operating conditions. The results revealed that 98.8C temperature was achieved under static air condition. The air temperature at the inlet of the cabinet under both natural and forced air velocities was about 62.8C. During the experiments, the cabinet was loaded with 426g of banana slices having an initial moisture content of 80%. The designed drying system managed to achieve a final desired moisture content of 15% within effective period of 7 hours without losing the product color.