Design and application of a mini all-weather solar dryer

In order to solve the problems in traditional drying technology of preserved fruits, a mini all-weather solar dryer was designed and manufactured based on characteristics and requirements of preserved fruits produced in Guangdong province. The solar dryer is composed of heat-collection plate, drying chamber and blower. It can collect sun radiation to heat air and water, store heat through hot water tank. It also has an assistant heating system in water tank. Forced air convective drying, natural convective drying and greenhouse drying can be reached by the designed dryer. The experiments of drying Ganshimei (intermediate moisture salted plum) were carried out to test the dryer’s performance. The working efficiency of heat-collection plate and drying chamber, the material balance and energy consumption of the drying system were calculated. And the parameters of the dryer were determined. The total drying efficiency of the forced air convective drying reached to a high level of 63.40%.Comparing with the traditional open sun drying, the drying rate of the forced air convective drying was 9.99 g/(100 g·h), which was 201.2% of the open sun drying’s. And the drying time of the forced air convective drying was 12 h, much less than 50 h of the open sun drying’s. Meanwhile the sugar and acid content loss of the forced air convective drying samples were less than that of the open sun drying samples.