Design, fabrication, and performance evaluation of a food solar dryer

One of the oldest techniques for preserving food is drying. Dehydrating foods reduces their moisture content and increases their shelf life by preventing microbiological activity. Food placed on the ground to dry in the sun is a common sight in rural areas of low- and middle-income countries but requires a large amount of land and can lead to food degradation by overexposure to the sun, insects, and vermin. This study designed, fabricated, and evaluated the performance of a solar dryer in comparison to direct sun drying for efficiency and product quality, utilizing bananas and potatoes as representative foods. The dryer was produced and tested within the context of Bangladesh, unlike other commercial devices. With its mild steel frame, fan, solar collector, and DC battery, the dryer achieved a drying efficiency of 49.2% by reaching a drying chamber temperature of 71 °C, which is 30 °C higher than ambient. Drying times were decreased, and samples of potatoes and bananas reached equilibrium moisture content in 6 h as opposed to 9 h for direct sun drying. The moisture content of solar-dried foods was between 12 and 13 percent, making them appropriate for long-term storage. Bioactive substances such as phenolic content and DPPH scavenging activity were reduced by 18% and 21%, respectively, in comparison to direct sun drying. Quality assessments showed that there was little loss in color and nutrients for solar-dried samples. With a one-year payback period, an economic attribute of 3.26, and a life cycle benefit of BDT 310,651 (USD 2597.68), economics show the dryer’s feasibility. The solar dryer functioned faster than direct sun drying due to its significantly higher heat generation. The solar dryer was more efficient, effective, and economic within the context of Bangladesh and other low- and middle-income countries.