EFFECTS OF MICROWAVE PRETREATMENT ON THE ENERGY AND EXERGY UTILIZATION IN THIN-LAYER DRYING OF SOUR

Energy and exergy analyses may be considered as important tools for design, analysis and optimization of thermal systems. This paper reports on energy and exergy analyses of thin-layer drying of sour pomegranate arils with mic-rowave pretreatment. There were two microwave pretreatments (100 W for 20 min and 200 W for 10 min) along with a control treatment (convection drying with no microwave pretreatment). Experiments were carried out at three air temperatures (50, 60 and 70 C) and three air velocities (0.5, 1 and 1.5 m/s). Results showed that energy utilization and energy utilization ratio increased with time, while exergy efficiency decreased. Energy utilization and drying time decreased considerably with microwave pretreatment of pomegranate arils. The minimum values of exergy loss and exergy efficiency were associated with the 200 W microwave pretreatment, while they were maximum for control treat-ment