跨临界CO2热泵系统性能研究

Study on Performance of Transcritical CO2 Heat Pump System

建立了跨临界CO_2热泵热水系统及其主要部件的数学模型并进行了模拟,利用自行搭建的跨临界CO_2热泵实验台进行了相关的实验研究。分析比较了气冷器的出口水温、气冷器的制热量与系统COP_h值（跨临界CO_2热泵系统）的仿真值与实验值,结果表明实验值与仿真值较为吻合,建立的系统模型准确性较高。利用仿真与实验的手段,研究了不同的冷却水流量和冷却水温度对跨临界CO_2热泵系统的性能影响。研究结果表明：系统运行时外部参数冷却水温度和流量及蒸发温度的变化将引起系统性能参数（制热量Q、系统COP_h值）变化,尤其是气冷器进口水温对系统性能的影响最大,为了保证气冷器中CO_2工质实现跨临界循环,降低气冷器进口水温是关键因素。

The high exhaust temperature and temperature slip of the transcrifical cycle of CO2 are suitable for water heating, and its application in the field of heat pump water heater has the advantages that other known working fluids cannot match. This paper established a mathematical model for the hot water system of a transcritical CO2 heat pump and its main components. And the numerical simulation and the experi- mental study for the transcritical C02 heat pump were carried out. The simulation and experimental values of the outlet water temperature of the gas cooler, the heat output of the gas cooler and the system COPh （transcritical CO2 heat pump system）were analyzed and compared. The results showed that the simulation values were in good agreement with the experimental results, indicating the high accuracy of system mod- el. The effects of different cooling water flow rate and cooling water temperature on the performance of transcritical CO2 heat pump system were studied by means of simulation and experiment. The results showed that the variation of cooling water temperature and flow rate and evaporation temperature will cause the change in the system performance parameters. In particular, the inlet temperature of the gas cooler has the greatest impact on the performance of the system. In order to scritical CO2 cycle in the gas cooler,it is the key factor to reduce the inlet cooler.