ABSTRACT

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, liability to pests and rodents lack of proper monitoring, and the escalated cost of the mechanical dryers, a solar dryer was therefore developed to cater for this limitations. This project presents the evaluation of ABE forced convectional mixed mode solar dryer. The dryer is made up of a solar drying chamber containing rack of three trays and collector consisting of a transparent glass cover and rock pebbles as the absorber. Solar energy of average of 578W/rn2 incident on the collector Of O.25m2 is transmitted and absorbed by rock pebbles to heat the forced air into the drying chamber by convection with the help of a D.0 fan powered by rechargeable battery charged by solar cells. Cocoyam of 5mm and 7mm thicknesses and wet moisture content of 80%Wb with different pretreatments of blanched with salt, blanched without salt and raw were dried to constant weight of 13% dry basis. The capacity of the ABE forced convectional dryer for the various samples used is 4.896kg and the drying efficiency of the dryer for sample blanched with salt 5mm, blanched with salt 7mm, blanched without salt 5mm, blanched without salt 7mm, raw 5mm and raw 7mm is 1.0%, 0.74%, 0.93%, 0.71%, 1.0%, 0.59% respectively