基于夹点的带喷射器CO2热泵系统性能分析
Performance analysis of CO2 heat pump systems with ejectors based on pinch point
摘要：
为了研究带喷射器的跨临界CO2内部过冷热泵系统(TCISE),基于夹点建立了TCISE的热力学模型,分析了冷却水进出水温度及流量对系统性能的影响。研究表明:冷却水进水温度从25 ℃降低到15 ℃时,最优高压压力从9.3 MPa降至8.8 MPa,降低了5.4%,最大COP从3.83提升至4.27,提高了11.49%;TCISE存在临界冷却水出水温度和临界冷却水质量流量,当冷却水进水温度一定时,在出水温度低于临界出水温度或质量流量高于临界质量流量时,系统COP保持不变。
Abstract：
In order to study the transcritical CO2internal subcooling heat pump system with an ejector (TCISE), a thermodynamic model of TCISE is established based on the pinch point, and the effects of the inlet and outlet temperatures and flow rate of cooling water on system performance are analysed. The results show that when the inlet temperature of cooling water decreases from 25 ℃ to 15 ℃, the optimal high pressure drops from 9.3 MPa to 8.8 MPa, which decreases by 5.4%, and the maximum COP increases from 3.83 to 4.27, which increases by 11.49%.There are critical cooling water outlet temperature and critical cooling water mass flow rate in TCISE.When the inlet temperature of cooling water is constant and the outlet temperature is lower than the critical outlet temperature or the mass flow rate is higher than the critical mass flow rate, the COP of the system remains unchanged.
Keywords:CO2 heat pump; ejector; pinch point; internal subcooling; cooling water; inlet temperature; outlet temperature; flow rate