Polyolester oil (POE oil) is a type of
synthetic oil
Synthetic oil is a lubricant consisting of chemical compounds that are artificially modified or synthesised. Synthetic lubricants can be manufactured using chemically modified petroleum components rather than whole crude oil, but can also be syn ...
used in refrigeration
compressors
A compressor is a mechanical device that increases the pressure of a gas by reducing its volume. An air compressor is a specific type of gas compressor.
Compressors are similar to pumps: both increase the pressure on a fluid and both can trans ...
that is compatible with the
refrigerant
A refrigerant is a working fluid used in the refrigeration cycle of air conditioning systems and heat pumps where in most cases they undergo a repeated phase transition from a liquid to a gas and back again. Refrigerants are heavily regulated ...
s
R-134a
1,1,1,2-Tetrafluoroethane (also known as norflurane (INN), R-134a, Freon 134a, Forane 134a, Genetron 134a, Green Gas, Florasol 134a, Suva 134a, or HFC-134a) is a hydrofluorocarbon (HFC) and haloalkane refrigerant with thermodynamic properties ...
,
R-410A
R-410A, sold under the trademarked names AZ-20, EcoFluor R410, Forane 410A, Genetron R410A, Puron, and Suva 410A, is a zeotropic but near- azeotropic mixture of difluoromethane (CH2F2, called R-32) and pentafluoroethane (CHF2CF3, called R-125) tha ...
and
R-12.
Definition of POE oil
HFC-134a with POE oil as the lubricant is a replacement for CFC-12 with mineral oil as the lubricant.lubrication
Lubrication is the process or technique of using a lubricant to reduce friction and wear and tear in a contact between two surfaces. The study of lubrication is a discipline in the field of tribology.
Lubrication mechanisms such as fluid-lubric ...
and stability and are more miscible with HFC refrigerants. They can meet the lubricity requirements to those of mineral oils used with CFCs and HFCs. They are compatible with most lubricants in the market.
Use
As the types of refrigerant gases used in AC and refrigeration equipment change, often due to the ozone-depleting or global warming characteristics of older refrigerants, the type of oil used in these systems sometimes must change as well to match the new refrigerants. POE oils are very good solvents and easily dissolve most of the residual mineral oils that they may be replacing. So even though small amounts of the old oil may remain, it won't clog the system.
Polyolester oil is used exclusively in jet turbine engines and often used in moving picture film cameras.
Problems
However, the same properties that make it a good solvent
A solvent (s) (from the Latin '' solvÅ'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for ...
for oils also make it a good solvent of undesired things left behind during the manufacturing of a unit. Some of which are: dust, dirt, residue from soldering, small bits of metal from cutting, and oxidized metal from the tubing. The residues collected can clog the system filters and cause excessive wear or damage to critical components such as the vanes or valves
A valve is a device or natural object that regulates, directs or controls the flow of a fluid (gases, liquids, fluidized solids, or slurries) by opening, closing, or partially obstructing various passageways. Valves are technically fitting ...
. This aspect makes it more important to check that components are machined properly, deburred, and cleaned. Another problem with these oils is that they are hygroscopic
Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption or adsorption from the surrounding environment, which is usually at normal or room temperature. If water molecules become suspended among the substance' ...
in nature, which means they can absorb moisture from the atmosphere. Hence, technicians working with units that have to be opened, should leave the unit open for as little time as required.[{{cite web , url=http://www.achrnews.com/articles/working-with-poe-oils-requires-forethought , title=Working With POE Oils Requires Forethought , publisher=Airconditioning news , accessdate=November 1, 2012]
In addition, POE oils typically have lower viscosity indexes than PAG or PAO oils, so that a higher viscosity grade is required in order to attain a certain kinematic viscosity at higher oil temperatures.
References
Non-petroleum based lubricants