ISSN 2384-5058
Abstract
Passive solar dryer plays an important role in postharvest handling of food processing and preservation in Africa. The passive solar crop dryer with two-stage collector was constructed at the workshop of the College of Agriculture, Science and Technology, Lafia using locally available materials. The performance of the dryer was evaluated. The temperature of the solar house, collector (absorber), dryer unit, ambient and wet bulb were undertaken hourly between the hours of 0900h to 0500h. The wind speed was also measured hourly to know the environmental air flow which average flow was 1.06m/s. Sample of marsh cassava of 8kg each was dried in the dryer and on the sun for comparative purposes. The dryer and sun-drying rates were 1.131kg/day and 1.22kg/day respectively. The mean temperature elevation (∆Tshd, ∆Tsha and ∆Tshc were 5.40C, 5.90C and 4.70C respectively). The cassava marsh dried in the dryer with the initial moisture content of 50.9% to 8.4%. The pickup, system and collector efficiencies were 5.1%, 4.9% and 59% respectively. The sun drying sample was moved to a safe place daily while dryer sample was left in the dryer well protected. Passive solar dryer reduces drying time and improve the quality of the crop.
Keywords: construction, performance evaluation, passive solar crop dryer, moisture content, Lafia, Nigeria