IIR document

Thermodynamic performance evaluation of an ejector-enhanced transcritical CO2 parallel compression refrigeration cycle.

Author(s) : BAI T., SHI R., YU J.

Type of article: IJR article

Summary

A parallel compression cycle is one efficient approach to improving the transcritical CO2 refrigeration cycle performance. This paper proposes a modified parallel compression transcritical CO2 refrigeration cycle with an ejector and a sub-cooler to further enhance the cycle performance. The thermodynamic analyses based on the energetic and exergetic analyses are conducted, and the influences of the parameters, including discharge pressure, flash pressure, gas cooler outlet temperature, and evaporation temperature, are discussed. The particle swarm optimization method is used to get the optimal discharge pressure and flash pressure and the temperature reduction in the sub-cooler with respect to the maximum COP. The performance comparisons between the conventional cycle and the modified cycle are presented. The results illustrate that the maximum improvements in COP and volumetric refrigeration capacity reach 15.8% and 17.1%. The utilization of the ejector and sub-cooler could reduce the optimal flash pressure by 16.4–33.0% and the compressor displacement by 11.4% compared with the conventional cycle. The ejector plays a dominant role in performance improvement at a high gas cooler outlet temperature. The exergy destruction analysis shows that the first-largest system exergy destruction ratio of 31.5% in the ejector-enhanced cycle is caused by the gas cooler, and its second-largest exergy destruction is generated in the two parallel compressors instead of the expansion valves in the conventional cycle.

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Pages: 49-61

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Details

  • Original title: Thermodynamic performance evaluation of an ejector-enhanced transcritical CO2 parallel compression refrigeration cycle.
  • Record ID : 30031532
  • Languages: English
  • Subject: Technology
  • Source: International Journal of Refrigeration - Revue Internationale du Froid - vol. 149
  • Publication date: 2023/05
  • DOI: http://dx.doi.org/10.1016/j.ijrefrig.2022.12.014

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