Performance measurements of transcritical R744 system using low-complexity ejector

Francesco Botticella, Zishen Liu, Stefan Elbel

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

CO2 is a promising refrigerant for numerous applications within the cold chain. The inherent throttling losses of the transcritical cycle can be mitigated by using two-phase ejectors. However, ejectors have yet to be successfully applied to mass-produced systems. Complex ejector designs drive product cost and reduce the likelihood of their widespread use. The focus of this paper is to systematically determine the performance trade-offs of less complex ejector designs. Various simplified motive nozzle and diffuser designs were experimentally investigated. While there are differences in ejector efficiency between the different motive nozzle designs on the order of 10 percent points, the effects on system performance (capacity and COP) are far less pronounced. That is especially true when a needle mechanism is used to control the high-side pressure. Therefore, the study demonstrates that reasonable system improvements can be achieved even with less complex ejector designs, enabling a more widespread use.

Original languageEnglish (US)
Title of host publication6th IIR Conference on Sustainability and the Cold Chain, ICCC 2020 - Proceedings
PublisherInternational Institute of Refrigeration
Pages189-196
Number of pages8
ISBN (Electronic)9782362150364
DOIs
StatePublished - 2020
Event6th IIR Conference on Sustainability and the Cold Chain, ICCC 2020 - Nantes, France
Duration: Aug 26 2020Aug 28 2020

Publication series

NameRefrigeration Science and Technology
Volume2020-August
ISSN (Print)0151-1637

Conference

Conference6th IIR Conference on Sustainability and the Cold Chain, ICCC 2020
CountryFrance
CityNantes
Period8/26/208/28/20

Keywords

  • Capacity and COP
  • Carbon Dioxide (CO, R744)
  • Ejector
  • Ejector Efficiency
  • Low-cost Design
  • Performance Trade-offs

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Electrical and Electronic Engineering
  • Mechanical Engineering
  • Condensed Matter Physics

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