Performance Evaluation of Chiller Unit with Gas Bearings Based on Energy, Exergy, Economic, and Environmental Analyses

Key Words:HEAT-PUMP SYSTEM; THERMODYNAMIC ANALYSIS; PERFORMANCE EVALUATION; CYCLE; IMPROVEMENTS; COMPRESSOR; EJECTOR; MIXTURE; R410A; PLANT

Abstract:Mechanical subcooling is an effective method to improve the transcritical CO2 refrigeration system. To further improve its performance, a transcritical CO2 refrigeration system is investigated with vapor injection and mechanical subcooling (MVS) using R152a as an auxiliary circulating refrigerant. A comparative analysis with the basic vapor injection CO2 refrigeration system (BVS) and the mechanical subcooling CO2 refrigeration system (MSS) is conducted from the perspective of energy and exergy. The results indicate that there are optimal values for the compressor discharge pressure, subcooling degree, and relative intermediate pressure coefficient, which together can maximize the COP of MVS under ious operating conditions. At an evaporation temperature of-15 degrees C and a gas cooler outlet temperature of 40 degrees C, MVS has a COP of 1.9, which is 17.8 % and 4.9 % higher compared to the BVS and MSS, respectively. The exergy efficiency is increased by 9.5 % and 6.6 %, respectively.

Volume:222

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Translation or Not:no