Effect of compressor speeds on performance of a closed loop heat pump drying system

In view of the current situation about environmental pollution and high energy consumption in industrial metal parts drying methods, a closed loop heat pump drying (CLHPD) system with a relatively high circulating air temperature was proposed and established. The compressor speed is a vital parameter that affects the performance of the CLHPD system. The effect of compressor speeds on circulating air temperature, coefficient of . . performance (COP), moisture extraction rate (MER) and specific moisture extraction rate (SMER) of the system were experimentally studied in this work. The results showed that, with the raise of compressor speed within . . 3000 to 4200 r/min, the drying air temperature and the MER of the system increased, the COP and SMER of the . system decreased. The drying air temperature reached a maximum of 75 ?C and the MER obtained a maximum of . 3.90 kg/h at the compressor speed of 4200 r/min. The COP reached a maximum of 6.4 and the SMER obtained a maximum of 1.62 kg/(kW.h) at the compressor speed of 3000 r/min. In an actual industrial production, the . compressor speed should be adjusted according to the specific demand to balance the relationship between MER . and SMER. These can provide references for further research and application of heat pump drying technology in the metal parts drying and even other industrial drying fields.

Automated summary

The closed loop heat pump drying (CLHPD) system proposed in this study aims to address environmental pollution and high energy consumption in industrial metal parts drying methods. The compressor speed was found to significantly impact the performance of the system in terms of circulating air temperature, coefficient of performance (COP), moisture extraction rate (MER), and specific moisture extraction rate (SMER). Adjusting the compressor speed can optimize the drying process and efficiency, providing valuable insights for further application of heat pump drying technology in various industrial settings.