Thermal energy storage based solar drying systems: a review

Solar dryer based on thermal energy storage materials is quite effective for continuously drying agriculture and food products at steady state in the temperature range (40 °C–60 °C). Such dryers have globally become a potential viable substitute to the solar dryers based on fossil fuel, due to the utilization of clean energy resources and cost-effectiveness. Storage materials utilized in these dryers can store energy during the sunshine hour and deliver the stored energy during off-sunshine. It reduces the existing load on the gap between energy demand and supply, hence plays a vital role in energy sustainability. A number of studies have been done in last few decades for drying agriculture and food products with a solar dryer based on thermal energy storage concept. This paper mainly presents a review on the important contributions made so far in the field of solar drying systems based on the thermal energy storage medium, with a focus on recent updates in thermal energy storage technology available in terms of materials capable of storing heat as sensible and latent heat.