Things to know about refrigeration oils

Just like a refrigerant is essential for the cooling within a refrigeration system, the oil also has an essential part to play to ensure the compressor in the system functions correctly. Lubrication is one of the most important factors in whether a refrigeration installation works correctly.


Choosing the right oil is essential for the performance and longevity of a refrigeration installation.


The selection of a lubricant will very much depend on the installation or application itself and more importantly which refrigerant type is in use.

Compressor manufacturers will specify the viscosity and type of oil for their compressors and a brand or brands which they approve.


The oil ensures that the different moving parts of the compressor are lubricated by forming a lubricating homogenous "film". Too low a viscosity and the mechanical parts will wear prematurely, too high a viscosity and the internal oil transport or energy efficiency can be affected. In rotary and screw compressors it is also an integral component of the compression process, it ensures tightness and therefore effective refrigeration.


The types of oil


Poly Alpha Olefin (PAO): they can be described as 'synthetic mineral oils' because of their identical structure to traditional mineral oils, the only difference being that they are manufactured from monomers such as ethylene. PAO oils can be used in refrigeration systems working in extreme conditions that are beyond the capabilities of many conventional mineral oils, thanks to their low pour points and excellent chemical and thermal stability. They have low miscibility with refrigerants and are compatible for use with most common refrigerants, including carbon dioxide and ammonia. PAO oils are fully miscible with most conventional mineral refrigeration oils but it should be noted any mixture of oils may detract from the performance properties of the PAO.


Polyol Ester (POE): it is the most common type of synthetic oil that can be used with HFC refrigerants. POE oils are excellent lubricants which are less hygroscopic than PAG variants and chemically more stable that PAG types when in the presence of water. POE oils are intended for use in all refrigeration and air conditioning applications.


Poly Alkylene Glycols (PAG): have a high viscosity index and thermal stability. PAG oils have a benefit in that they are able to lock in moisture to prevent it being an issue in a refrigeration system. They are extremely stable within the harsh environments of R744 systems. PAG based lubricants are suitable for use with most commonly used refrigerants including ammonia and carbon dioxide.


Alkyl Benzene (AB): have enhanced thermal and chemical stability and superior miscibility with hydrochlorofluorocarbons (HCFCs) allowing use at low temperatures. Alkyl benzene oils are not generally recommended for use with HFCs. They are compatible with all traditional mineral oils which they can replace where the system malfunctions with the original lubricant, but it should be noted any mixture of oils may detract from the performance properties of the oil. Very low pour and flow points help to prevent harmful wax precipitation that can block expansion valves and heat transfer surfaces.


Mineral: mixtures of virtually wax-free hydrocarbons used for the lubrication of refrigeration compressors, selected for their excellent fluidity at low temperatures. This kind of lubricant is particularly suited for use with CFC, HCFC refrigerants and ammonia.


Hydro Treated Mineral Oils (HTMO): Refrigeration equipment using ammonia often requires a specific type of oil to ensure correct operation. We offer these two commonly used hydro-treated oils for ammonia applications.


Here at Climalife we have a wide range of refrigeration oils available from all the major brands and can offer a range of packaging size options.


View our oil range sheet

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