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Feasibility study of dedicated R744 ejector for compressor oil return.

Number: 0025

Author(s) : ALAM M. M., HAIDER M., ELBEL S.


In vapor compression refrigeration systems, ejectors have been extensively considered for expansion work recovery and improvement of evaporator performance. However, ejectors could be used in a novel way to pump the compressor lubricant and ensure improved oil return to the compressor as the oil return is most often very crucial in both small as well as large-scale systems. This paper presents a feasibility study for utilizing an ejector to provide a pumping effect to an oil-rich refrigerant/lubricant mixture and return oil from the evaporator to the compressor. This study is performed through a numerical modeling approach considering suitable ejector cycles. An R744/oil combination is used for conducting the numerical study with a reasonable assumption of fixed oil circulation rate (OCR). The results obtained from the considered ejector model illustrate the effect of the motive flow rate and the oil suction flow rate on the pressure lift and ejector efficiency characteristics. The preliminary results from the numerical model suggest the possibility to utilize ejectors for compressor lubricant pumping from the evaporator and returning it to the compressor.

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Pages: 8 p.


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  • Original title: Feasibility study of dedicated R744 ejector for compressor oil return.
  • Record ID : 30029663
  • Languages: English
  • Subject: Technology
  • Source: 15th IIR-Gustav Lorentzen Conference on Natural Refrigerants (GL2022). Proceedings. Trondheim, Norway, June 13-15th 2022.
  • Publication date: 2022/06/13
  • DOI:
  • Document available for consultation in the library of the IIR headquarters only.


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