Characteristics And Experimental Study On The Performance Of An Auto-cascade Refrigeration System

Along with the development of the aerospace industry, metal products,electronic components, special industry and metallurgical products, the demands ofcryogenic temperature, auto cascade refrigeration system has got extensive attentiondue to its simple structure, good stability, and can meet the low temperatureenvironment in the refrigeration field. According to this, this paper adopts thesingle-stage compression, a form of segregation, using non zeotropic refrigerants forR22/R23as refrigerant, the first and the second law of thermodynamics on thethermodynamic characteristics were analyzed based on the experimental study, thedifferent ratio, different evaporation temperature and different liquid ratio and so onsystem parameters the performance of the system. We get the following conclusions:1)Based on the first law of thermodynamics and the second law ofthermodynamics, combine with the thermodynamic model of auto-cascaderefrigeration cycle, studied the effects of the seperated liquid ratio of R22, massflow ratio of R22/R23, pressure ratio, the ecaporation temperature and the quantityof heat on the performance of the system. The results show that: when R22entersthe evaporator condenser with larger share, with mass flow ratio of R22/R23increases, the system COP is also a corresponding increase; when R22and R23ratiois in the range of1.0~1.8, positively correlated with COPL.2) Constructed a R22/R23automatic test platform cascade refrigeration system,studied on the effect of different composition and R22performance liquidcomparison system with expriments. The results show that: the temperature in thelow-temperature container, the input and output drops dramaticlly in5minutes afterthe system started running. In different proportions, the system can achieve thestable operation of the state in30minutes; in different evaporating temperature,when the working fluid on the ratio in the range of1.4~1.6, there will always be aextreme value of the total of COP of the system.The innovation of this paper lies in the selection of the design of auto cascaderefrigeration system with two evaporating box, high temperature and lowtemperature refrigeration box working at the same time, it can be used not only onthe study of the proporty of the heat and refrigeration of the common evaporativecondenser; but also makes full use of the medium between the cascade, the residualheat of high boiling point matter can be fully utilized, and improved theperformance of the system in the same time. The experimental stude on thetwo-temperatures evaporature of this paper is an important guidance and valuebolreference on the cold storage of a machine and fridge and so on.