Performance characteristics of a two-stage transcritical N_2O refrigeration cycle with vortex tube

摘要

The thermodynamic analysis has been presented in this article using nitrous oxide as the refrigerant in a two-stage transcritical cycle with the vortex tube (TSTCVT) instead of the expansion valve and its results are compared with the two-stage transcritical cycle with the expansion valve (TSTCEV). The evaporator and the gas cooler temperature ranges in both the cycles have been considered between -55°C to 5°C and 35°C to 60°C for the analysis. Gas cooler and intercooler pressures are simultaneously optimised to obtain the maximum cooling coefficient of performance (COP). The COP of the TSTCVT improves by 1.97-27.19% in comparison to TSTCEV. A decrease in evaporator temperature and an increase in gas cooler exit temperature reduce the COP of TSTCVT. The comparison of refrigerants N_2O and CO_2 in TSTCVT shows that N_2O exhibits higher cooling COP, higher second law of efficiency and lower optimum gas cooler pressure under the considered operating conditions.