Study of Heat Pump Assisted Microwave Drying

To investigate the performance and feasibility of heat pump assisted microwave drying, a prototype dryer with a heat pump compressor rating of 5 kW and a maximum microwave power of 10 kW, was consrmcted and a mathematical model of the dryer was developed. Extensive drying tests using foam rubber and some vegetables have been conducted using this prototype dryer. The comparison between the experimental and numerical performance data showed good agreement. The influences of the key design and operating parameters have been examined. In panicular, the influence of the applying time of microwave power on the performance of the microwave dryer was shown to be negligible when drying non-hygroscopic materials. The results of the study indicated that with careful design heat pump assisted microwave drying is comparable to conventional convective drying in energy consumption.