Design and construction of a crystallized solar salt dryer

Abstract

The crystallized salt solar drying system utilizes solar energy to heat up air and to dry salt, which is beneficial in reducing wastage of salt product and helps in preserving it. Based on the limitations of the natural sun drying e.g. exposure to direct sunlight, liability to pests and rodents lack of proper monitoring, and the escalated cost of the mechanical dryer, a solar dryer is therefore developed to cater for this limitation. This project presents the design, construction and performance of a mixed-mode solar dryer for salt. In the dryer, the heated air from a separate solar collector is passed through a cabinet bed, and at the same time, the drying cabinet absorbs solar energy directly through the transparent roof. The results obtained during the test period revealed that the temperatures inside the dryer and solar collector were much higher than the ambient temperature during most hours of the day-light. The temperature rise inside the drying cabinet was up to 55% for about three hours immediately after 12.00h (noon). The dryer exhibited sufficient ability to dry salt reasonably rapidly to a safe moisture level and simultaneously it ensures a superior quality of dried products. The major objective of the project was therefore to design and construct a crystallized salt solar dryer which would dry salt to acceptable quality standards and also dry them in the least amount of time of five hours. The specific objectives set included designing a solar dryer prototype and testing for its effectiveness and performance.