CO_(2)跨临界热泵高温化途径分析

ANALYSIS ON APPROACHES FOR INCREASING HEAT SUPPLYING TEMPERATURE OF CO_(2) TRANSCRITICAL HEAT PUMP

CO_(2)作为一种环境友好的自然工质,以其为循环工质的跨临界热泵制热能力突出。建立CO_(2)跨临界增压和CO_(2)跨临界热泵理论分析模型,研究不同增压过程对热泵系统COP、气冷器中水的出口温度及质量流量的影响规律。结果表明,2种热泵高温化方案均会提升压缩机等熵效率、功耗和压缩机出口工质温度,且提升了气冷器出口水温,但COP和热水的质量流量有所降低。综合来看,随气冷器出水温度的增加,增大压缩机吸气过热度的循环耗功上升幅度较小,但COP下降幅度较大,可在小范围内提升热水温度;提高压缩机出口压强能获得更高的热水温度,可控范围更大,且COP降低幅度较小。

The transcritical heat pump with CO_(2),an environmentally friendly natural working fluid,shows great potential in high temperature heating.A CO_(2)transcritical pressurization analysis model and a CO_(2)transcritical heat pump analysis model have been established.Based on them,the effects of different pressurization processes on COP,outlet temperature and mass flow rate of water in gas cooler are studied.The results show that both approaches can improve the isentropic efficiency,power and outlet working fluid temperature of the compressor,and increase the outlet water temperature of the gas cooler,but decrease the COP and hot water mass flow.In general,when increasing the outlet water temperature of gas cooler,the approach of increasing the suction superheat makes power increases slightly,but the COP decreases greatly,which can increase hot water temperature in a small range.By increasing the compressor outlet pressure,the hot water temperature is higher,the controllable range is larger,and COP has a smaller decline.