Performance of a Recirculation Type Integrated Collector Drying Chamber (ICDC) Solar Dryer

A novel recirculation type ICDC solar dryer has been designed, constructed and tested. The solar dryer was comprised of a feed hopper, centrifugal blower, pneumatic conveyor and a transparent structure acting as drying chamber containing a hopper with vortex at the top. Test with 104 kg of rough rice indicated that the drying time required to reduce the moisture content of rough rice from 28.4% wet basis (wb) to the final moisture of 14.3%wb was 5 hrs. During the test the drying temperature was kept constant at 50.1°C and relative humidity (RH) of 21.73%. The required power for the pneumatic conveyor was 581 W with total energy input of 210.7 MJ including LPG and solar radiation. The resulting drying efficiency was 22.4% with specific energy of 15.2 MJ/kg of water evaporated. Another test using 200 kg with initial moisture content (m.c.) of 27.6%wb.of rough rice have shown that the required drying time to achieve the final moisture of 14.3% was 8 hrs. During the test the drying temperature was kept at 46.9 C, and RH of 21.7%. The drying efficiency was 31.7% with specific energy of 10.7 MJ/kg water evaporated.