Performance Optimization Analysis of An Air-source Heat Pump with Multi-Stage Waste Heat Recovery

Abstract

In this paper presents the effect of different outdoor ambient temperatures and heating temperatures on the performance of an air-source heat pump drying system with multi-stage waste heat recovery has been analysed by recording actual operating status of the system for a little longer-term period. The results show that COP of the heat pump with any heat recovery mode will increase with heating temperature reduction or ambient temperature rising like that does it without heat recovery. As outdoor ambient temperature increasing, the suitable heat recovery mode to enhance COP of the heat pump drying system changes from mode 1-3 to mode 1-2-3 and then to mode 1-2. Especially outdoor low-temperature ambient conditions in winter, 1-3 under would both enhance COP and improve the problem of evaporator frost. But the waste heat utilization rate ηT of whole system is lowest. Moreover, it can be supposed by comparing η with ηT that the first-stage heat exchanger unit of the heat recovery system and the energy transfer fluid circulating in the system would be potential for optimization to further enhance the performance of whole air-source heat pump drying system.