三种跨临界 CO2制冷循环的性能对比研究

摘要

The performance difference of trans-critical CO2 throttle valve cycle,trans-critical CO2 internal heat exchanger cycle and trans-critical CO2 expander cycle was investigated by theoretical analysis and nu-merical simulation.The results showed that:under the same conditions,the cooling capacity of internal heat exchanger cycle was the biggest and throttle valve cycle was the smallest;the power dissipation of in-ternal heat exchanger cycle was the biggest and the expander cycle was smallest;the COP of expander cy-cle was the biggest and throttle valve cycle was the smallest;the compressor discharge temperature of inter-nal heat exchanger cycle was higher than throttle valve cycle and expander cycle.To sum up,the COP of throttle valve cycle was the smallest.Internal heat exchanger cycle could improve the system cooling ca-pacity,but it also increased the compressor discharge temperature.Expander cycle could reduce system power dissipation effectively,and could more significantly improve system COP,it had the better perform-ance.%对跨临界 CO2节流阀循环、跨临界 CO2回热器循环、跨临界 CO2膨胀机循环三种跨临界 CO2制冷循环进行了理论分析和模拟计算，研究了三种循环的性能差异。结果表明，相同条件时，回热器循环的制冷量最大，膨胀机循环次之，节流阀循环最小；回热器循环的功耗最大，节流阀循环次之，膨胀机循环最小；膨胀机循环的 COP 最大，回热器循环次之，节流阀循环最小；回热器循环的压缩机排气温度高于节流阀循环和膨胀机循环。综上可得，节流阀循环的 COP 最小，回热器循环能够提高系统的制冷量，但是会导致压缩机排气温度的升高，膨胀机循环能够有效地减少系统功耗，对系统COP 的提升更为显著，综合性能更好。