Performance Simulation of a Two-Cycle Heat Pump Dryer for High-Temperature Drying

Abstract

Heat pump drying has a great potential for energy savings due to its high energy efficiency in comparison to conventional air drying. However, the heat pump dryer is usually operated at temperatures less than 50°C and the drying temperature is limited by the operating temperature of the heat pump system. The special heat pump dryer proposed in the present study can be used to increase the drying temperature. The dryer uses the two-cycle heat pump system in which two different heat pump cycles operate at the high and low temperature ranges to generate the drying air of high temperature. One cycle uses the refrigerant 124 to get a temperature greater than 80°C and the other cycle uses the refrigerant 134a. The system performance has been investigated with parameters such as the total coefficient of performance (COP) of the heat pump, the moisture extraction rate (MER), the specific moisture extraction rate (SMER) of the dryer, and so on.

Keywords:

• COP
• Heat pump dryer
• MER
• SMER
• Two-cycle heat pump

ACKNOWLEDGMENTS

This work was supported by the Korea Energy Management Corporation. The authors appreciate the support.