A Study on Autocascade Refrigeration System Using Carbon Dioxide and R134a Mixture

  • Park, Soo-Nam (Institute of Advanced Machinery and Design, Seoul National University) ;
  • Kim, Min-Soo (School of Mechanical and Aerospace Engineering, Seoul National University)
  • Published : 2001.03.01


Investigation of the performance of an autocascade refrigeration system using the refrigerant mixtures of R744 (carbon dioxide) and R134a (1,1,1,2-tetrafluoroethane) has been carried out by simulation and experiment. Cycle simulation using a constant UA model in heat exchangers has been performed for R744/134a mixtures of the compositions ranging from 10/90 to 30/70 by weight. Variations of mass flow rate of refrigerant, compressor work, refrigeration capacity and COP with respect to mass fraction of R744/134a mixture were presented. Performance test has been executed in the autocascade refrigeration system by varying secondary fluid temperatures at evaporator and condenser inlets. Experimental results match quite well with those obtained from the simulation.