Measuring Lubricant Concentration in the Mixture with Refrigerant: A Comprehensive Review

Lubricants in mechanical vapor compression systems play an important role in lubrication and thermal insulation. During system operation, small quantities of oil are observed to dissolve with working fluid. Oil migration from the compressor results in refrigerant lubricant mixture, which effects the thermophysical and thermodynamic properties of working fluid. A prediction of oil composition can help in determining properties in refrigerant/lubricant mixture. A lot of reviews have been published regarding to lubricants, their interaction with refrigerants, their thermophysical properties and effect on overall system. However, there is a need for systematic database for oil concentration evaluation methods. This review paper focuses on an overview of various techniques to measure oil concentration in refrigerant/lubricant mixtures. This review provides an overview of oil concentration evaluation methods based on various properties of the refrigerant lubricant mixture.