摘  要   NH3/CO2 組合制冷系統是完全自然工質制冷系統。在分析 NH3/CO2 復疊制冷循環系統和 NH3/CO2 相變二次冷媒系
統的T－S圖和 P－H圖的基礎上，分別比較了這兩種系統在一定工況下的COP、NH3 用量和CO2用量。計算結果表明這兩
個系統的COP都存在極值， 但是NH3/CO2復疊制冷循環系統的COP受運行工況影響更加明顯； 對于CO2用量而言， NH3/CO2
復疊制冷循環系統CO2用量要大于NH3/CO2相變二次冷媒系統CO2用量；對于NH3用量，這兩種系統用量沒有明顯差別。
這說明NH3/CO2相變二次冷媒系統在低溫系統運行更加安全和可靠。
關鍵詞  制冷  相變二次冷媒  復疊制冷  自然工質
 
PERFORMANCE COMPARSION OF TWO DIFFERENCTCOMBINED
REFRIGERATION SYSTEMS OF NH3/CO2
Liu Bin  Cai Jinghui  Dong Xiaoyong  Zang Runqing,
(Tianjin Key Lab of Refrigeration Technologies, Tianjin University of Commerce, 300134)
 
Abstract   The combined refrigeration system of NH3/CO2 is the completely friendly refrigeratoin system using nature
refrigerants. Based on the analyses of T-S and P-H diagram of the NH3/CO2 cascade refrigeration system and the
NH3/CO2 phase change secondary medium  refrigeration system, COP, the quantity of NH3 and CO2 of the two
systems were compared. The calculated  results show that COP have a maximum value about the two system, but the
maximum value of COP of the NH3/CO2 cascade refrigeration system is more easily affected by the working conditions
that that of the NH3/CO2 phase change secondary medium    refrigeration system. As for the quantity of CO2, the value
of the NH3/CO2 cascade refrigeration system is larger than that of the NH3/CO2 phase change secondary medium
refrigeration system. But as for the quantity of NH3, there is little difference between the two systems. This implies that
under low temperature, the NH3/CO2 phase change secondary medium refrigeration system is safer.
Keywords    Refrigeration    Phase change secondary medium   Cascade refrigeration  Nature refrigerant