Designs, Performance and Economic Feasibility of Domestic Solar Dryers

Abstract

Present article is an overview of available solar drying technologies developed for small rural agricultural farms emphasizing domestic applications. A huge amount (about 61%) of perishable items gets wasted annually at the household level due to lack of awareness, negligence, improper handling, and inadequate storage facilities. Domestic solar dryers are reviewed and presented under the categories of natural and forced convection modes. The maximum attainable temperature inside the drying chamber under natural and forced convection mode is observed 98.6 and 78.1 °C, respectively. Thermal efficiency of solar dryers varies from 5.16 to 64.36% for the drying of various commodities. Natural convection solar dryers are appropriate for rural and undeveloped areas due to simple design and lower capital and electrical requirements. In comparison, forced convection solar dryers are more attractive due to better performance, higher drying rate, and lower drying time for high moisture content products. The designs of indirect and mixed-mode solar dryers seem very rare in the area of domestic solar drying. Solar dryers have potential to reduce the conventional drying cost by 50% and improve the return by 30%.