高温CO2热泵的超临界喷气增焓性能

提出了一种基于高温超临界喷气增焓技术的新型CO₂热泵循环，以显著提升跨临界CO₂热泵在高温循环加热工况下的制热性能。通过建立超临界喷气增焓型高温CO₂热泵系统的数值模型，并采用EES（engineering equation solver）软件对该热泵系统的循环加热性能进行了仿真分析。研究了在较高气体冷却器出口温度下，蒸发温度、压缩机中间压力、气体冷却器压力等参数对单位容积制热量和性能系数（COP）的影响。结果表明：在最优排气压力下，气体冷却器出口温度高达60℃时，该热泵循环的COP也能达到3.0左右；相对于普通喷气增焓系统，COP明显提高；相对于无喷气增焓的常规系统，在气体冷却器出口温度为60℃时，相对补气量为0.3、0.4、0.5的超临界喷气增焓系统COP分别提高了14.8%、21.2%、29.2%；气体冷却器压力和中间压力对系统COP的影响变化趋势一致，但气体冷却器压力的影响更为显著；此外，存在最优的气体冷却器压力和中间压力使系统COP达到最大，在气体冷却器出口温度为60℃，相对补气量为0.4时，最优气体冷却器压力和中间压力分别为13.5MPa和8.5MPa。

Performance research on high temperature CO2 heat pump with supercritical enhanced gas injection

A novel high temperature CO₂ heat pump cycle with supercritical enhanced gas injection was proposed to significantly improve heating performance under high temperature hydronic heating conditions. The numerical model of the high temperature CO₂ heat pump system with supercritical gas injection was established, and the performance of the system was analyzed by EES (engineering equation solver) software. The influence of parameters such as evaporation temperature, middle pressure of compressor, gas cooler pressure, etc. on system performance at the high gas cooler outlet temperature was mainly studied. The results indicated that COP of 3.0 can be reached when the gas cooler outlet temperature was as high as 60℃. In comparison to common vapor injection system, the COP improved distinctly. As compared to conventional system without gas injection, the COP increased by 14.8%, 21.2%, 29.2% respectively with gas injection ratio of 0.3, 0.4, 0.5 at the gas cooler outlet temperature of 60℃. The influence of middle pressure and gas cooler pressure on COP have the same variation trend while the effect of gas cooler pressure is more significant. Besides, there exist an optimal gas cooler pressure and middle pressure. The optimal gas cooler pressure and middle pressure are 13.5MPa and 8.5MPa, respectively, when the gas cooler outlet temperature is 60℃ and the gas injection ratio is 0.4.