This paper documents an investigation of electrical and optical properties of oil-refrigerant liquid mixtures as possible bases for a real-time measurement of oil concentration. In addition to brief results from a literature survey of these properties, descriptions of experimental procedures and results from laboratory measurements of dielectric constant, light absorption characteristics, and refractive index in liquid mixtures of refrigeration oils and R-113 are presented. Also included is a discussion of instrumentation which could be adapted to oil concentration measurement. Potentially successful prototype oil concentration sensors, based on capacitance measurement and refractive index measurement, have been recommended for continued development.

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