Novel lubricant for high temperature heat pump applications on its way

Fuchs Schmierstoffe is developing, within the DryFiciency project, a new lubricant for high-temperature heat pumps using the refrigerant OpteonMZ.

Fuchs Schmierstoffe is developing, within the DryFiciency project, a unique synthetic lubricant for high-temperature heat pumps. This lubricant is chemically stable when combined with OpteonMZ, which is a novel, non-flammable and non-toxic new refrigerant from Chemours, that is not subject to the F-gas regulation. The lubricant is being used for two compressor technologies in DryFiciency project - an adapted screw compressor by Bitzer and a new piston compressor technology by Viking Heat Engines. 

High-temperature heat pumps require specially designed lubricants, suitable for extreme working conditions. High temperatures up to 160°C and a maximum 18 bar pressure decrease the viscosity of the lubricant and refrigerant mixture. Furthermore, the lubricant needs to be miscible with the refrigerant, so it has to be chemically stable.

The refrigerant selected for the DryFiciency project, OpteonMZ (HFO-1336mzz-Z) from Chemours, is a novel HFO (Hydrofluoroolefin), which is non-flammable and non-toxic. Furthermore is not subject to the F-gas regulation. However, it is more reactive than classic HFC (Hydrofluorocarbon) without a double bond in the molecule. To suppress an undesired reaction between the refrigerant and the lubricant, the last one requires an optimized additive system which prevents the degradation of both.

Within the DryFiciency project, Fuchs developed a unique synthetic lubricant that is well miscible with OpteonMZ from Chemours. The kinematic viscosity from the lubricant and the refrigerant is high enough to sustain the working points of the screw and piston compressor technologies used. The additive system, used to improve the thermal and chemical stability of the lubricant and the refrigerant, was optimized in several aging tests.

Author:

i.A. Dennis Ebert , RnD Industrial Oils

FUCHS SCHMIERSTOFFE GMBH

 

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