Refrigerant additive compositions containing perfluoropolyethers
View Patent ↗The present invention relates to compositions and processes of using perfluoropolyether to maintain or improve the oil return, lubrication, cooling capacity, or energy efficiency of a refrigeration, air conditioning or heat transfer system.
1. A method of producing refrigeration, said method comprising evaporating a composition in the vicinity of a body to be cooled and thereafter condensing said composition; wherein said composition consists of:
a. a refrigerant or heat transfer fluid consists of 2,3,3,3-tetrafluoro-1-propene (CH 2 ═CFCF 3 ) or 1,3,3,3-tetrafluoro-1-propene (CHF═CHCF 3 ); and
b. at least one perfluoropolyether; and optionally
c. a lubricant oil which is mineral oil or synthetic oil selected from the group consisting of alkylbenzene, polyol ester, polyalkylene glycols, polyvinyl ethers, carbonates, polyalphaolefin and combinations thereof;
wherein said perfluoropolyether has two end groups;
wherein at least one of the end groups of said perfluoropolyether is selected from a group consisting of carboxylic acids and sulfonic acids;
and wherein said evaporating and said condensing is in a stationary refrigeration, air-conditioning, heat pump or mobile refrigeration system.
2. The method of claim 1 , wherein the amount of perfluoropolyether in said composition is less than about 40% by weight relative to said refrigerant or heat transfer fluid.
3. The method of claim 1 , wherein at least one of the end groups of said perfluoropolyether is carboxylic acid.
4. The method of claim 1 , wherein at least one of the end groups of said perfluoropolyether is sulfonic acid.
5. The method of claim 1 , wherein the stationary refrigeration system is a domestic refrigerator or freezer, an ice machine, a self-contained cooler or freezer, a walk-in cooler or freezer or a supermarket system.
6. The method of claim 1 , wherein the stationary air-conditioning system is a window, ductless, ducted, packaged terminal, chiller, light commercial or commercial air-conditioning system.
7. The method of claim 1 , wherein the mobile refrigeration system is a refrigeration system incorporated into a transportation unit for the road, rail, sea or air.