STUDY OF HEAT-PUMP ASSISTED MICROWAVE DRYING

To investigate the performance and feasibility of heat pump assisted m icrowave drying, a prototype dryer with a heat pump compressor rating of 5 kW and a maximum microwave power of 10 kW, was constructed and a mathematical model of the dryer was developed. Extensive drying tests using foam rubber and some vegetables have been conducted using this p rototype dryer. The comparison between the experimental and numerical performance data showed good agreement. The influences of the key desi gn and operating parameters have been examined. In particular, the inf luence of the applying time of microwave power on the performance of t he microwave dryer was shown to be negligible when drying non-hygrosco pic materials. The results of the study indicated that with careful de sign heat pump assisted microwave drying is comparable to conventional convective drying in energy consumption.