Field Drying of Cassava in a Solar Tent Dryer equipped with a Solar Chimney

Abstract

The performance of a solar tent dryer equipped with a solar chimney , as against that of open sun drying , was examined in the drying of cassava . An initial no - load trial was done , followed by trials with the dryer loaded with cassava . One drying trial was performed with the crops on the lower shelf , another with the crops on the upper shelf and a third trial with the dryer loaded on both the lower and upper shelves . In each drying trial , some cassava were also dried in the open sun which results were compared to that of the dryer . In the no - load process , the temperature inside the dryer increased with height due to thermo - syphon effects . But this trend was distorted by the evaporation of moisture from the crops during the drying processes , especially at the initial stages . About 75% to 80% of the drying process occurred within the first two days and nights of the drying periods . The open - sun drying was faster at the initial stages of drying , especially when the crops were on the lower shelf or the dryer was fully loaded . But the performance of the dryer overtook that of the open sun drying at later stages of drying . Thus , the dryer started more slowly but finished earlier than the open - sun drying . The best drying performance was observed when the crops were high up the dryer , though only a small amount of crops could be allowed at this height due to the design of the dryer .