Comparative study of transcritical vapor compression configurations using CO2 as refrigeration mode base on simulation

Despite of the excellent efficiency of the CO2 transcritical cycle in heat pump mode, there is a loss of efficiency in refrigeration mode compared with the subcritical vapor compression cycle with HFC refrigerants. This reason has lead several researches to propose ways to improve the transcritical cycle performance using CO2 as refrigerant in refrigeration mode, mainly associated to cycle configurations changes. In this paper, a comparative study and energetic simulation of most common configurations for transcritical single stage cycle using CO2 as refrigerant has been carried out. In order to make the comparison, a cycle components modelization has been proposed and the simulation results are used to find the optimum configuration for a single stage vapor compression transcritical system.