Oil in refrigerant circuits

The behaviour of lubricating oil in a refrigerant circuit and its physical interaction with the refrigerant itself is a dominant factor in the design of circuits in general and evaporators in particular. 

Refrigeration compressors are mechanical devices with component parts which slide together, so requiring lubrication to reduce friction, remove frictional heat and assist with gas sealing. 

Lubricants for general commercial systems are based on mineral oils, and the following properties are required of the lubricant selected  

It must be compatible with the refrigerant, i.e. not form any compounds or promote chemical activity. 

The mixture with the refrigerant in the lubrication circuit must provide adequate lubrication of the working parts. 

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