A solar powered food and crops drying system for utilization of refrigeration waste heat

Abstract

One of the main goals of the majority of cold chain operations is to decrease perishable post-harvest losses. Another useful technique for lowering post -harvest loss is drying. Nevertheless, the commercial drying methods currently in use require a lot of energy. High levels of greenhouse gasses are released during operation. Drying applications could make use of low-grade waste heat recovered from the refrigeration system's condenser. The technique involves the efficient use of heat that is intermittently produced by a refrigeration system's condensing unit with an external energy source of a solar collector that was used for drying during day as a source of heat to the condenser heat. The system was tested using cassava and tomatoes under various loading conditions, with performance assessed through temperature monitoring in both chambers, moisture content of cassava, and economic evaluation. An average temperature of 130C was maintained in the cooling chamber and for the drying chamber, a temperature of 32.0°C was used for the drying process at night and a 50.3°C during day time with combined heat from the solar collector and condenser heat. Results showed effective drying and cooling performance, reduced energy demand, and promising economic indicators, including a favourable net present value and internal rate of return. This proved to be a viable alternative to the comparatively more energy-intensive industrial drying technologies in use today.