1999 Volume 61 Issue 2 Pages 171-180
The characteristics of dehumidified drying of raw garlic bulb in a closed air recirculation system was investigated under different air conditions with temperatures of 15, 25, 35 and 40°C and humidifies of 30, 45, and 60%. The rate of weight reduction were 0.16%/h for 40°C-30% r. h., 0.04 to 0.14%/h for 15 to 35°C and 30 to 60% r. h. compared to 0.08%/h by natural shade drying in the open air. The final moisture content of cloves in a garlic bulb was not reduced to less than 63% in every experiments. Thermal efficiency was 25.8 to 36.2% under 40°C-30% and 35°C-30 to 60% r. h., respectively, and lower at air conditions of 25°C-60% r. h. and 15°C-45 to 60% r. h.. Energy efficiency curve, which indicate the energy required to remove one (1) kg of moisture, increased as an exponential function with decreasing temperature and humidity increase. Water and heat balance equations were proposed for dehumidified drying in a closed air recirculation system. These equations were verified by calculations using the figures obtained in the experiment.
