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An investigation on the dissociative heat of low-gwp refrigerant/lubricant oil mixtures for the reliable design of refrigerant compressors.

Number: 1365

Author(s) : ABIRHAM Y., IKEDA Y., CHENG Y., MIYAZAKI T.

Summary

This study presents an investigation carried out to build an understanding of the dissociative heat of low-GWP refrigerant/lubrication oil mixtures. The dissociative heat is the heat that is generated (or absorbed) when the refrigerant gas dissolves in (or dissociates from) the refrigeration oil. Understanding of this behavior is important because the lubrication property of the lubricant oils is influenced by the thermal interactions with their surroundings. A theoretical model that predicts the dissociative heat was derived by combining a solubility model with the Clausius-Clapeyron equation and solving for the enthalpy change at the refrigerant-gas/lubricant phase equilibrium. Once the dissociative heat model was built, solubility data of low-GWP refrigerant/lubrication oil mixtures was collected from the literature and the model was tested. The considered mixtures were namely, R1234yf/POE(POE75), R1234ze(E)/POE(POE75), R1243zf/POE(RL68H), and R290/mineral oil mixtures. The calculated dissociative heat values were found to be generally consistent for all the mixtures. It was found that the dissociative heat is strongly affected by the system pressure. Analysis of the results seem to suggest that the further the state of the refrigerant gas from its corresponding saturation state at a given temperature, the higher the dissociative heat will be. Therefore, decrease in the system temperature at constant pressure or increase in the pressure at constant temperature will yield lower dissociative heat values. Generally, the results indicate that a significant quantity of heat (comparable to the latent heat of the refrigerant) is absorbed/released during the dissolution process of the refrigerant and lubricant oil. Such thermal interactions could influence the lubrication capability of the oil, and hence consideration of such effects could be a useful input towards the improvement of the reliability and performance of the refrigerant compressors. Because sustaining an effective oil film between the moving parts of the compressor is crucial to minimize the wear and the associated losses caused by the direct metal-to-metal contact.

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  • Original title: An investigation on the dissociative heat of low-gwp refrigerant/lubricant oil mixtures for the reliable design of refrigerant compressors.
  • Record ID : 30033607
  • Languages: English
  • Subject: Technology
  • Source: 2024 Purdue Conferences. 27th International Compressor Engineering Conference at Purdue.
  • Publication date: 2024/07/18

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