The energy, emissions, and drying kinetics of three-stage solar, microwave and desiccant absorption drying of potato slices

In this study, a three-stage solar dryer using solar convection, convection-microwave, and solar desiccant absorption-assisted convection drying was developed and evaluated. This process was designed to reduce energy consumption and Carbon emissions while retaining the color properties of the dried food product. Potato slices were dried in the first stage using solar convection and the process was assisted by Microwave radiation in the second stage to increase the drying rate. The final stage combined solar desiccant absorption with solar convection to maintain the drying rate at a lower temperature, thereby reducing energy use and minimizing thermal damage to the biomass. Compared to Microwave-Convection drying, the three-stage drying process was found to consume 46 % lower specific energy and reduced Carbon emissions by 53 %. The Vitamin – C retention and color retention were found to improve by 27 % and 8.55 % respectively. The proposed design is promising and can be used to improve the overall performance of solar thermal drying methods in terms of temperature control, energy efficiency, sustainability, and product quality. It also has the potential to be deployed in rural areas with minimal dependence on grid energy.