Tribological Evaluation of Contacts Lubricated by Oil-Refrigerant Mixtures

The tribological characteristics of the most common contact geometries found in compressors of air conditioning and refrigeration systems have been experimentally investigated by means of a unique high pressure tribometer (HPT). The HPT has been used to experimentally simulate the friction and wear behavior of various metal contact pairs lubricated by oil-refrigerant mixtures in environments found in compressors. The refrigerants used in this program are CFC-12 to obtain baseline data and its prime replacement candidate, HFC-134a. The CFC-12 has been tested with mineral oils and synthetic alkylbenzenes while the HFC-134a has been tested with monoether polyalkylene glycol (PAG's) and pentaerythritol polyolester oils. Since the amount of refrigerant dissolved in the oil is a function of both pressure and temperature, and the friction and wear of a given contact can be significantly affected by the concentration of refrigerant in the oil, the friction and wear data obtained from this test program should be a good indicator of what can be expected in compressors.Air Conditioning and Refrigeration Center Project 0