Present status of solar crop drying

Abstract

Significant developments of the past decade in the area of solar crop drying are reviewed. Increasing energy prices stimulated research on solar drying in highly mechanized agricultural systems. However, in those countries solar drying has to compete with automated crop dryers using fossil fuels as the energy source. Studies have shown that neither the temperature required nor the quantity of heat necessary in high-temperature batch type or continuous-flow dryers can be reached with solar collectors. Therefore solar energy cannot be adapted economically to high-temperature drying systems. Solar energy is considered more applicable to low-temperature in-storage drying systems which has gained more importance in the last decade for drying grain and hay. Conditions in tropical and subtropical countries make the use of solar energy highly recommendable. The introduction of solar crop dryers seems to be a way to lower mass losses compared to traditional drying methods and improves the quality of the product considerably. Solar drying can be a way to increase the food supply and it also can be a possibility to increase the income of the rural population.