PERFORMANCE ANALYSIS OF A NOVEL ENHANCED TRANSCRITICAL N2O REFRIGERATION CYCLE FOR POWER AND COLD GENERATION

Abstract

Performance evaluation of the three special transcritical refrigeration cycles, specifically the vapor compression cycle (VCC), the combined refrigeration cycle (CRC) and the new combined refrigeration cycle for power and cold generation (NCRCPC), are studied. The principles of mass and energy conservation are implemented to every devices of the cycle, and the resulted linear system of equations was numerically solved. It was investigated that the new proposed cycle had a lesser optimum gas cooler pressure than VCC and CRC refrigeration cycles, and this would enhance the lifetime and safety of the system. It was found that the COP of the new cycle is more than that of the vapor compression and combined refrigeration cycles 118.73% and 49.146%, respectively. Besides, The exergy efficiency was approximately 64.55% and 56.68% higher than that of the vapor and combined refrigeration cycles, respectively. If we compare between N2O and CO2 refrigerant, the N2O based refrigeration cycle is found to have better coefficient of performance (COP), lower gas cooler pressure and higher entrainment ratio (u). For N2O based refrigeration cycle maximum COP is found to be more than that of CO2 based refrigeration cycle. Exergetic output of N2O ejector cycle is better while losses passed off because of irreversibility during expansion is lower.