摘  要   NH3/CO2 组合制冷系统是完全自然工质制冷系统。在分析 NH3/CO2 复叠制冷循环系统和 NH3/CO2 相变二次冷媒系
统的T－S图和 P－H图的基础上，分别比较了这两种系统在一定工况下的COP、NH3 用量和CO2用量。计算结果表明这两
个系统的COP都存在极值， 但是NH3/CO2复叠制冷循环系统的COP受运行工况影响更加明显； 对于CO2用量而言， NH3/CO2
复叠制冷循环系统CO2用量要大于NH3/CO2相变二次冷媒系统CO2用量；对于NH3用量，这两种系统用量没有明显差别。
这说明NH3/CO2相变二次冷媒系统在低温系统运行更加安全和可靠。
关键词  制冷  相变二次冷媒  复叠制冷  自然工质
 
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