带膨胀机的CO2空调系统循环的研究

设计并比较了3种具有可行性的CO2跨临界循环.计算结果表明,当膨胀机效率大于19%时带膨胀机的两级压缩循环较双级节流循环的要好,膨胀机效率大于45%时,带膨胀机的单级压缩循环COP比双级节流循环要高.另外,通过引入当量温度分析法,将带膨胀的CO2跨临界循环与R134a循环进行了对比.结论是CO2双级带膨胀机循环的稳定性好,当量冷凝温度较大时单级带膨胀机循环性能高于R134a循环,当量冷凝温度较低时,R134a循环性能与双级带膨胀机循环不相上下.

Study on Carbon Dioxide Air Conditioning Cycle with an Expander

Three kinds of feasible CO2 transcritical cycles are proposed and compared. The calculation indicates that double stage compression cycle with an expander has advantage over double stage cycle with a throttling valve when the expander efficiency is greater than 19%, and provided that the expander efficiency is higher than 45%, single stage cycle with an expander is superior to double stage cycle with a throttling valve. In addition, CO2 transcritical cycles with an expander are compared with R134a cycle by means of equivalent temperature analysis. The comparison demonstrates that CO2 double stage cycle with an expander has good stability, and at high equivalent condensing temperature single stage cycle with an expander is preferable to R134a cycle, while at low equivalent condensing temperature double stage cycle with an expander is equal to R134a cycle.