Oil circulation rate in ejector cooling cycles

Jingwei Zhu, Francesco Botticella, Stefan Elbel

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

Abstract

The use of two-phase ejectors to recover expansion work to improve COP of transcritical R744 systems has been the subject of numerous investigations during the past decade. However, there is little understanding as to how oil in circulation in different parts of the system is affected when a two-phase ejector is used to replace the expansion valve. This paper presents detailed measurement results conducted on a transcritical R744 ejector system using polyalkylene glycol (PAG) oil, demonstrating that at the same test condition, the oil circulation rates (OCRs) in different parts of the system can easily vary by an order of magnitude. The highest OCRs of approximately 10% by mass were measured close to the evaporator inlet. The influence of compressor speed, ejector motive nozzle needle position and evaporator inlet metering valve opening on the OCRs was investigated and it is explained why these condition changes will result in variation of oil in circulation.

Original languageEnglish (US)
Title of host publication5th IIR Conference on Sustainability and the Cold Chain, ICCC 2018 - Proceedings
PublisherInternational Institute of Refrigeration
Pages86-95
Number of pages10
ISBN (Electronic)9782362150241
DOIs
StatePublished - Jan 1 2018
Event5th IIR Conference on Sustainability and the Cold Chain, ICCC 2018 - Beijing, China
Duration: Apr 6 2018Apr 8 2018

Publication series

NameRefrigeration Science and Technology
Volume2018-April
ISSN (Print)0151-1637

Conference

Conference5th IIR Conference on Sustainability and the Cold Chain, ICCC 2018
CountryChina
CityBeijing
Period4/6/184/8/18

Keywords

  • Carbon dioxide
  • Ejector
  • Oil in circulation
  • Two-phase

ASJC Scopus subject areas

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

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