Impact of sensible and latent heat energy storage combined on drying kinetics and quality of potato slices in a mixed mode solar dryer: Experimental and economic study

Solar dryers enable sustainable and efficient dehydration and preservation of food products. Integration of energy storage in solar dryers improve their efficiency considerably through extended drying time post sunshine hours. This experimental study integrates both sensible energy storage (SHES) and latent heat energy storage (LHES) into a mixed mode solar dryer to investigate its impact on drying kinetics, economics and nutritional quality with potato slices as the product. The key drying kinetics parameters are plotted to reveal the influence of combination of SHES and LHES on performance of the mixed mode solar dryer. A reduction in drying time by 53 % was achieved in comparison to open-sun drying, with a drying rate of up to 0.491 kg/h. The drying efficiency went up to 10 % with combined thermal energy storage, indicating effective storage and retrieval of energy from both thermal energy storage materials, especially post peak-sunshine hours. Provision of combined energy storage had positive impacts on the moisture removal rate and specific energy consumption of the dryer system. A remarkable economic payback period of 0.39 years was calculated for the solar dryer through combined thermal energy storage, despite its higher initial investment. A higher retention of the vitamin C content of potato slices were also observed in the quality assessment of the dried products, along with better aesthetic appearance and texture.