Abstract: The adaptability of air source heat pump to low ambient temperature environment restricted its wide application in north of China.Enhanced vapor injection air source heat pump(ASHP)system with flash-tank as economizer was one of the most efficient method to solve the problem of low temperature adaptability for air source heat pump.By developed mathematical model of the enhanced vapor injection air source heat pump,influce on the heat pump's performance by first stage compression ratio and pressure loss coefficient were studied.The results show that optimum first stage compression ratio exits.Because with the gradual increase of the first stage pressure ratio,the condensation pressure decreases slowly and the heat pump's coefficient of performance(COP)increases gradually,while the compressor's exhaust temperature decreases first and then increases.Based on an overall consideration of discharge temperature of compressor and ASHP COP,first stage compression ratio was 1.6 in simulated condition.Large pressure loss coefficient means little useful work loss,and larger pressure loss coefficient leads to larger heating capacity,power input,ASHP COP and lower discharge temperature.Therefore,lower pressure loss coefficient should be an important aim in practical design.

Key words: thermodynamics process, enhanced vapor injection air source heat pump, pressure loss coefficient, first stage pressure ratio

摘要： 空气源热泵系统低温适用性问题一直是其在北方拓广应用的制约性因素，带有闪发器的补气增焓空气源热泵系统是解决空气源热泵低温适用性的有效手段之一。本文建立了带有闪发器的补气增焓空气源热泵系统的热力学过程数学模型，通过数值模拟研究了一级压缩比和压力损失系数对补气增焓空气源热泵系统特性的影响。结果表明，随着一级压比的逐渐增大，冷凝压力降低趋势平缓，热泵的性能系数逐渐升高，而排气温度先降低后升高，因而存在最佳一级压比。综合压缩机的排气温度和热泵的性能系数，模拟工况补气增焓空气源热泵的最佳一级压比为1.6。补气压力损失系数越大意味着有用功的损失越小，随着补气压力损失系数增大热泵的制热量、耗功逐渐增大，性能系数逐渐升高而排气温度逐渐降低，因此设计时应补气压力损失系数越大越好。

关键词: 热力学过程, 补气增焓空气源热泵, 补气压力损失系数, 一级压比