Detachable Heat Storage for Nighttime Dehydration in Solar Food Dryers

Abstract

The operation of the solar-powered dehydrator (SPD) works only in daytime as the system relies on solar radiation. It causes certain technical barriers, especially for drying high water content food products. To overcome the challenge, a heat storage apparatus (HSA) is integrated to enhance the operation at nighttime. In this work, we propose a novel concept for integrated HSA-SPD. The HSA employs a multicell arrangement and works in a passive-active system. The proposed model is installed as a separate component, which allows the HSA can be detached during the daytime. Experimental tests are performed by adjusting the discharging period of HSA for two different SPD models: greenhouse (GH) and drying cabinet (DC). The finding shows the nighttime dehydration without using SPD evaporates around 11.6% water content of the products for 10 hours of operation, while GH and DC indicate a higher rate around 16.4% and 21.3%, respectively. Discharging the HSA at the initial dehydration stages leads to a lower evaporation rate with total water removal only 20.7% (GH) and 28.9% (DC), compared to discharging at the second dehydration that leads to a higher water removal up to 26.1% (GH) and 33.8% (DC). It shows detachable HSA offers flexible operation to maximize dehydration rate for SPD in nighttime operation.