Experience of Solar Drying in Africa: Presentation of Designs, Operations, and Models

摘要

Africa has a very high solar insolation and a large agrarian sector with a lot of drying of agricultural products carried out with mostly open sun drying. However, efforts have been made by researchers based in Africa working, under changing climatic conditions, to develop solar drying systems, using materials that are locally available. The challenge was that the solar dryers should be used to dry different kinds of products including fish, medicinal plants, fruits, wood, and vegetables and bring the studied material to low moisture content. Most of this research has been obscured since Africa is not at the forefront of solar research, coupled with technological and economic laid-backness. The solar dryers' designs consist of direct, indirect natural or forced convection dryers or even mixed mode. These collectors are mostly tilted southwards at an angle of inclination ranging from 0 degrees to 60 degrees to the horizontal. Design has focused on the utilization of available local materials with some dryers that can be equipped with supplementary heating source or a storage of energy. Solar drying research among the African countries is very low generally and requires investment to boast it. Therefore, this review highlights solar dryers evaluated within the African region, including the quality of the final product, their efficiency, and prediction of its behavior using simulation and mathematical modeling. Pointing the area of future research and development is also emphasized.