Development and Performance Evaluation of Hybrid-Solar Dryer for Cassava Grate

Abstract

A solar hybrid dryer for cassava grate was fabricated and evaluated for performance. The major components include chimney, drying chamber, solar collector, blower housing (heater and fan) unit, solar panel, aluminum frame, rollers and 12 V direct current battery. Evaluation of the hybrid dryer was carried out to investigate the effect of drying temperature and variety of cassava (TMS96/1414, TMS92/0326 and TMS01/1368) on moisture loss, drying rate and drying efficiency. The dryer recorded maximum temperature of 55ᵒC and 45ᵒC in the drying chamber for hybrid and solar drying respectively which are higher than the 26ᵒC recorded for ambient. In all the experiments performed it took 7 hours for the moisture content of sample using hybrid solar drying to be reduced from average of 65% to about 10.19%. For solar drying it took 13 hours to attain moisture content of 11% while open sun drying took 35 hours to reduce the moisture content to 13 %. The result showed that TMS96/0326 had the highest moisture loss (6.20 kg/kg, 6.09 kg/kg and 5.65kg/kg) drying rate (0.899 kg/hr, 0.870 kg/hr and 0.807 kg/hr) for open sun, solar and hybrid drying respectively. This confirmed that variety and temperature had effect on the drying performance. The drying efficiency for hybrid drying was 78.71 %, 79.71 % and 73.42 % while solar drying had 47.76 %, 48.38 % and 44.53 % for TMS96/1414, TMS92/0326 and TMS01/1368 respectively; an indication that temperature, airflow rate and variety of cassava grate had significant effect on evaluated parameters hence the hybrid solar dryer is efficient for achieving dry cassava grate.