HVAC/R system refrigerant and oil conditioning, composition, and method for removing acid and moisture therewith

Abstract

A refrigerant and oil treatment composition for introduction into a vapor-compression system such as a refrigerator, heat pump, freezer, air conditioner, thermal control device, and refrigerant recovery apparatus has a composition alcohol and a drying agent. The drying agent is 2,2-dimethoxypropane which can react with moisture in the system to form an alcohol as a reaction product. The alcohol reaction product along with the composition alcohol separates any acid in the system from oil, refrigerant and hard surfaces of the system to form an acid-containing solvent composition. The quantity of the composition introduced into the system is based on the adsorption capacity of the filter-drier.

Claims

1. A vapor compression system, comprising a filter-drier, and a composition of alcohol selected from the group consisting of ethanol, methanol, isopropanol and mixtures thereof and a drying agent consisting of 2,2-dimethoxypropane, wherein the drying agent is reactable with moisture in the system to form an alcohol as at least one reaction product so that acid in the system is separated from oil, refrigerant and hard surfaces of the system to form an acid-containing solvent product that is removed from the system by the filter-drier.

2. The system of claim 1, wherein a quantity of the composition in the system is based on the adsorption capacity of the filter-drier.

3. A method of removing acid and moisture in a vapor-compression system, comprising introducing a composition having alcohol selected from the group consisting of ethanol, methanol, isopropanol and mixtures thereof and a drying agent consisting of 2,2-dimethoxypropane into the system, wherein the drying agent can react with the moisture in the system to form at least one reaction product as an alcohol, and using the formed alcohol and the composition alcohol to separate the acid from the oil.

4. The method of claim 3, wherein the introduction of the composition occurs at a low-pressure side of the system during operation by a pressure differential between high and low pressure sides of the system.

5. The method of claim 3, wherein a low-pressure service port comprises a connection to the low pressure side and a high-pressure service port is the connection to the high pressure side.

6. The method of claim 3, wherein the acid-containing solvent composition is removed by passing the vaporized solvent through a filter-drier of the system.

7. The method of claim 3, wherein the system is one of a refrigerator, a heat pump, a freezer, an air conditioner, a thermal control device, a refrigerant recovery apparatus, a refrigerant recycling apparatus and a refrigerant reclamation apparatus.

8. The method of claim 3, wherein the drying agent is present in a concentration between about 1 and 99 percent by mass.

9. The method of claim 3, wherein the alcohol proportion of the composition is present in a concentration between 1 and 99 percent by mass.

10. The method of claim 3, wherein a high viscosity liquid or viscosity modifier is added to match a viscosity of lubricating oil in the system.

11. The method according to claim 3, wherein introducing the composition comprises providing a quantity of the composition based on an adsorption capacity of filter-drier associated with the system.

12. The method according to claim 3 wherein the introduction of the composition is into a compressor oil sump of the system.

Description

DETAILED DESCRIPTION OF THE INVENTION

(1) We have discovered that 2,2-dimethoxypropane and if desired additional alcohol can be used to effective and rapidly remove moisture and acid from the HVAC/R system, whereby the moisture is reacted and the acid is liberated from the system, including the oil and hard surfaces, by the methanol produced from the reaction and any additional alcohol that has been added thus allowing the liberated acid to flow into the filter drier where it is removed. We have found that the alcohol can be ethanol, methanol, or isopropanol.

(2) The preferred embodiment of the formulation is a mixture that is about 1% to 100% by weight 2,2-dimethoxypropane combined with about 0% to 99% weight percent ethanol thereby removing the moisture from the refrigerant and oil by consuming the water molecules and producing methanol and acetone and the methanol produced along with added ethanol liberates the trapped acid from the system (including hard surfaces, refrigerant and oil lubricant) allowing the alcohol and acid to be adsorbed in the filter-drier. This formulation effectively works with all refrigerants and lubricants including CFC, HCFC, HFC, and HFO refrigerants and both mineral and synthetic lubricants.

(3) The alcohol and drying agent formulation is best added to the oil sump of the compressor since the majority of the acid and moisture are in the oil and the oil sump represents the largest accumulation of oil anywhere in the system. The currently preferred embodiment to introduce the formulation to the oil sump is to introduce it into the low-pressure side of a system, via an existing service port since this will lead directly to the oil sump of the compressor.

(4) The pressure differential between the low pressure side and high pressure side of an operating system can be used to push the alcohol and drying agent formulation additive into the system using an apparatus described in U.S. Pat. No. 5,996,651.

(5) Instead of using the pressure difference to push the drying agent formulation additive into the low pressure side of an operating system, it is well known in the art to use a pressurized container that is filled with the alcohol and drying agent formulation and then pressurized with the refrigerant of the system, or one of the refrigerants of the system, if the refrigerant is a blend of refrigerants, and use the higher pressure in the container at ambient temperature conditions to push the additive into the low pressure side of the operating system.

(6) Alternatively, the drying agent formulation additive can be introduced into the system by the method described in pending U.S. patent application Ser. No. 14/959,395, filed Dec. 4, 2015 and titled “System and Method Introducing Liquid Additive into a Vapor Compression System via a Pressurized Can and Optionally for Purging a Connecting Hose”. In this method of additive introduction, the liquid additive is packaged in a vessel, like an aerosol can. A gas is then added to the vessel also during the vessel filling process and the vessel is pressurized to near but above atmospheric pressure and always to a pressure below a design operational low-side pressure of the system where the additive will be eventually introduced. To introduce the additive into a vapor compression system, the vessel that contains the liquid additive is connected to a low-side service port of the system. In a first or upright position of the vessel, with the system compressor not operating, and just prior to making the final connection to the system at the low-side service port, the gas in the vessel is used to purge the line connecting the vessel to the low-side service port, until the pressure in the vessel is at atmospheric pressure, then the final connection is completed and the vessel is re-pressurized by the low-pressure of the system, until the pressures in the vessel and the system are equalized. Thereafter, in a second or inverted position of the vessel, with the system compressor now operational, the liquid additive is drawn into the system. Then with the system compressor again not in operation and the vessel returned to the first position, any liquid additive that has not been introduced into the system lines and remains in a connecting hose is flushed back into the vessel.

(7) While we have shown and described a currently preferred embodiment in accordance with our invention, it should be understood that the same is susceptible of further changes and modifications without departing from the scope of our invention. We, therefore, do not intend to be limited to the details shown and described herein but intend to cover all such changes and modifications that are encompassed by the attached claims.