Analysis and Optimization of the Injection Characteristics and Comprehensive Performance of Low Gwp Refrigerant Hp-1 in High Temperature Heat Pump Systems

Abstract

At present, in the context of low GWP refrigerants becoming a research hotspot, the environmentally friendly refrigerant HP-1 with independent intellectual property rights in China has demonstrated its advantages in fields such as data centers and 5G base stations. However, there are few applied studies in the field of high-temperature heat pumps(HTHP), and this study applied HP-1 to HTHP and combined it with the injection technology which has been proven to be an effective way to improve performance. The injection characteristics of HP-1 HTHP were analyzed and optimized with a focus on safety, stability, and efficient operation. The application advantages of HP-1 were compared and analyzed in terms of thermodynamic performance and Total Equivalent Warming Impact (TEWI). The results indicated that there were three types of characteristic injection pressures based on system performance, which correspond to the maximum COP, the lowest Electronic Expansion Valve (EEV) inlet refrigerant temperature, and the lowest exhaust temperature of the compressor, respectively. The corresponding control equations for injection pressure were obtained. Based on the safety injection pressure, the optimal COP injection pressure can effectively improve the system COP by 3.1% ~ 8.0%, and the exhaust temperature will also increase by 6% ~ 8%. When the temperature of the heat source was 50℃ and the condenser water inlet temperature was 120℃, the heating capacity of HP-1 increases by 10.8% compared with that of R245fa, the COP of the system increases by 2.7%, and the VHC increases by 10.3%. Moreover, the emission reduction effect of HP-1 was significant, and the carbon dioxide emissions was reduced by 15.4%~39.1%. The above analysis showed that HP-1 has better performance and environmental characteristics than HFC-245fa. This study was of guiding significance to improve the thermodynamic performance of HTHP, safe and efficient operation, and energy saving and emission reduction in the industrial field.

Keywords: HP-1 HTHP, Environmentally-friendly refrigerant, Injection Characteristics, Performance analysis optimization, Decarbonization.