DESIGN, CONSTRUCTION AND EVALUATION OF A PASSIVE SOLAR DRYER

The solar drying system utilizes solar energy to heat up air and to dry any food substance loaded, which is not only beneficial in that it reduces wastage of agricultural produce and helps in preservation of agricultural produce. Based on the limitations of the natural sun drying such as exposure to direct sunlight, liable to pests and rodents due to lack of proper monitoring, and the escalated cost of the mechanical dryers. This project presents the design and construction of a passive solar dryer, the dryer is composed of solar drying chamber containing rack of three trays. The air allowed in is heated up in the solar collector and channeled through the drying chamber where it is utilized in drying (removing the moisture content from the food substance). The dimensions of the dryer was 94cm x 45cm x 101cm x 20cm (length x width x height). Locally available materials were used for the construction, chiefly comprising of wood (plywood), glass, and net for the trays. The mass of water removal of 199.9g and 153.6g in cassava and plantain respectively using the solar dryer was achieved as against 156.8g and 125.3g in cassava and plantain respectively using the sun drying method and indicating 43.1g and 28.3g difference respectively, for ten slices of cassava and plantain over a particular day. The rapid rate of drying in the dryer reveals its ability to dry food items reasonably rapidly to a safe moisture.