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Oil circulation rate measurements with flow-through and evacuated type sampling cylinders.

Number: 2212

Author(s) : HAIDER S. A., WANG X., ELBEL S.

Summary

To reduce the frictional wear and tear between the moving parts of the compressor, most vapor compression systems make use of different lubricating oils. The oil can leave the compressor and can get circulated around the system or get retained at specific locations. Oil circulation rate (OCR) is defined as the percentage by mass of circulating oil in the oil-refrigerant mixture. Since OCR is known to affect system performance, it is very important to be able to accurately measure OCR. The ASHRAE standard 41.4 describes the method of OCR measurement employing an oil sampling technique with an evacuated type sampling cylinder. However, this method has certain limitations, and past research on the topic has shown that results can vary between evacuated type and flow-through type sampling cylinders.
The present work provides an experimental comparison between sampling results for the flow-through type and evacuated type sampling cylinders in a vapor compression system using R134a as refrigerant and PAG 46 oil as lubricant. The compressor speed was varied from 1500 min-1 to 2500 min-1. The OCR sampling data were recorded with the system at steady-state, and online oil concentration sensor data were also taken to provide additional insights. Details of the flow patterns in the evacuated sampling cylinder were observed using a high-speed camera, and some of the key factors affecting OCR data obtained using the evacuated sampling cylinder were discussed.

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Pages: 10 p.

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Details

  • Original title: Oil circulation rate measurements with flow-through and evacuated type sampling cylinders.
  • Record ID : 30030608
  • Languages: English
  • Subject: Technology
  • Source: 2022 Purdue Conferences. 19th International Refrigeration and Air-Conditioning Conference at Purdue.
  • Publication date: 2022

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