Performance Of A Conventional Solar Dryer Under Local Climatic Conditions Of Mbarara In Uganda

Abstract

Open-air sun drying of agricultural products is still practiced largely in ways unchanged from ancient times after harvest. There is always contamination, theft or damage by birds, rats or insects; slow or intermittent drying and no protection from rain or dew. In addition, large areas of land are needed for the shallow layers of food; laborious since the crop must be turned, moved if it rains; reduction in quality (color and vitamin content) of some fruits and vegetables. These problems can be solved through the use of a solar dryer. A solar dryer which is cheap (purchase and maintenance costs) for the population and environmentally friendly was constructed. The agricultural products considered for experimentation were sweet potatoes and cassava. Their drying rates inside and outside the solar dryer were determined. It was observed that the average drying rates inside the solar dryer and in open-air are 0.21 g/h and 0.17 g/h for sweet potatoes and 0.29 g/h and 0.22 g/h for cassava, respectively. The conventional solar dryer, in addition to saving time, protecting the products from dirt and animals and drying products without cracking which minimizes the exposure of the crops to fungal and bacteria infestation and wastage, it dries products faster than open-air sun drying.