Abstract

Air Conditioning and
Refrigeration Systems Oil Fouling

Air conditioning and refrigeration systems contain a compressor in which, during the normal course of the refrigeration process, the compressor's lubricating oil comes in direct contact with the refrigerant. Since the early days of refrigeration and air conditioning technology, the American Society of Heating, Refrigeration and Air-Conditioning Engineers (ASHRAE) have addressed the results of the interaction between the compressor oil and the refrigerant. This mixture continuously migrates throughout the entire air conditioning or refrigeration system.

In the Refrigeration Handbook, published by ASHRAE, it is stated that some lubricating oil is lost from all compressors during normal operation. Since oil inevitably leaves the compressor with the discharge gas, systems using halocarbon refrigerants must return this oil at the same rate at which it leaves.^* ASHRAE states that unless oil is removed periodically or continuously from the point where it collects, it can cover the heat transfer surface in the evaporator, reducing performance.**