摘要： 【中文摘要】 在復疊制冷實驗臺上對由CO2/R290組成的不同配比的二元混合制冷劑進行了低溫循環性能實驗。實驗結果表明,隨著CO2含量增大,二元混合物的壓比減小,制冷量增大,耗功減少,COP增加,制冷速率增大。但隨著CO2含量增大,二元混合物的排氣溫度也升高,當CO2在混合物中的組分達到71%時,蒸發溫度為-61℃時,壓縮機的排氣溫度接近115℃。因此,混合物中CO2含量不宜超過71%。混合物中R290降低了CO2凝固點溫度,同時也降低了CO2較高的冷凝壓力,對擴展CO2在低溫區域的應用很有益處。 【英文摘要】 The experiment on concentration ratio of CO2/R290 in the low-temperature circuit of a cascade refrigeration system was conducted in our study.The results show that the refrigeration capacity,the COP,and the refrigeration rate increased while the pressure ratio and the power input decreased with the increase in the CO2 concentration ratio.However,the increase in the CO2 concentration ratio resulted in the increase in the discharge temperature,and the discharge temperature of the compressor was up to 115℃ when the concentration ratio of CO2 was 71% and the evaporating temperature was-61℃.It is suggested that the concentration ratio of CO2 should not exceed 71%.In addition,R290 in the mixture could reduce the freezing point and the condensing pressure of CO2. 【中文關鍵詞】 熱工學; 復疊制冷; 混合制冷劑; 低溫; 濃度配比【英文關鍵詞】 Pyrology; Cascade refrigeration; Mixture refrigerant; Low temperature; Concentration ratio