Method for Producing Hydrocarbon Refrigerant Gas as a Replacement for an HFO or HFC Refrigerant

Abstract

An instrument-grade, blended hydrocarbon refrigerant gas that can be utilized in both existing air conditioning systems and that is suitable for air conditioning systems in hybrid vehicles and EV's. The instrument-grade blended hydrocarbon refrigerant gas is a mix of propane and butane, either iso-butane or n-butane, at a selected ratio and serves as an environmentally friendly substitute for hydrofluoro refrigerant gases such as hydrofluorocarbon refrigerant gas and hydrofluoro-olefin refrigerant gas.

Claims

1. An instrument-grade blended hydrocarbon refrigerant gas for replacing a hydrofluoro refrigerant gas in an air conditioning system, wherein said blended hydrocarbon refrigerant gas comprises: an instrument-grade propane in a selected amount by liquid volume, said instrument-grade propane having less than a 5 percent moisture content and having less than percent by weight volatile impurities; instrument-grade butane in a selected amount by liquid volume, said instrument-grade butane having less than a 5 percent moisture content and having less than 0.5 percent by weight volatile impurities; and a non-conductive synthetic lubricant.

2. The instrument-grade blended hydrocarbon refrigerant gas of claim 1 wherein said instrument-grade blended hydrocarbon refrigerant gas further comprises a drying agent.

3. The instrument-grade blended hydrocarbon refrigerant gas of claim 1 wherein said instrument-grade blended hydrocarbon refrigerant gas is formulated to replace a hydrofluorocarbon refrigerant gas, wherein said instrument-grade blended hydrocarbon gas is approximately 50% to 80% propane by liquid volume and approximately 20% to 50% butane by liquid volume.

4. The instrument-grade blended hydrocarbon refrigerant gas of claim 3 wherein said instrument-grade blended hydrocarbon refrigerant gas is formulated to replace a hydrofluorocarbon refrigerant gas, wherein said instrument-grade blended hydrocarbon gas is approximately 50% propane by liquid volume and approximately 50% butane by liquid volume.

5. The instrument-grade blended hydrocarbon refrigerant gas of claim 3 wherein said instrument-grade butane is iso-butane.

6. The instrument-grade blended hydrocarbon refrigerant gas of claim 3 wherein said instrument-grade butane is n-butane.

7. The instrument-grade blended hydrocarbon refrigerant gas of claim 1 wherein said instrument-grade blended hydrocarbon refrigerant gas is formulated to replace a hydrofluoroolefin refrigerant gas, wherein said instrument-grade blended hydrocarbon gas is approximately 70% to 90% propane by liquid volume and approximately 10% to 30% butane by liquid volume.

8. The instrument-grade blended hydrocarbon refrigerant gas of claim 7 wherein said instrument-grade blended hydrocarbon refrigerant gas is formulated to replace a hydrofluoroolefin refrigerant gas, wherein said instrument-grade blended hydrocarbon gas is approximately 70% propane by liquid volume and approximately 30% butane by liquid volume.

9. The instrument-grade blended hydrocarbon refrigerant gas of claim 7 wherein said instrument-grade butane is iso-butane.

10. The instrument-grade blended hydrocarbon refrigerant gas of claim 7 wherein said instrument-grade butane is n-butane.

11. The method for replacing a hydrofluoro refrigerant in an air conditioning system with an instrument-grade hydrocarbon refrigerant gas of claim 1 wherein said non-conductive synthetic oil is a polyolester oil.

12. A method for replacing a hydrofluoro refrigerant in an air conditioning system with an instrument-grade hydrocarbon refrigerant gas, said method comprising the steps: selecting a ratio of propane and butane by liquid volume wherein said ratio is selected based on a type of hydrofluoro refrigerant gas being replaced; reducing a moisture content of said propane and said butane below 5% by weight; reducing volatile impurities below 0.5 percent by weight; removing ethane from said propane and from said butane; removing a hydrofluoro refrigerant from said system with a reclaiming machine so as not to release any of said hydrofluoro refrigerant to the atmosphere; injecting said blended instrument-grade blended hydrocarbon refrigerant gas into said air conditioning system.

13. The method for replacing a hydrofluoro refrigerant in an air conditioning system with an instrument-grade hydrocarbon refrigerant gas of claim 12, said method further comprising the step of reducing said moisture content below 10 mg/kg.

14. The method for replacing a hydrofluoro refrigerant in an air conditioning system with an instrument-grade hydrocarbon refrigerant gas of claim 12, said method further comprising the step of adding a non-conductive synthetic oil to a compressor of said air conditioning system to lubricate said compressor of said air conditioning system.

15. The method for replacing a hydrofluoro refrigerant in an air conditioning system with an instrument-grade hydrocarbon refrigerant gas of claim 14 wherein said non-conductive synthetic oil is a polyolester oil.

16. The method for replacing a hydrofluoro refrigerant in an air conditioning system with an instrument-grade hydrocarbon refrigerant gas of claim 12 wherein said steps of selecting said ratio of propane and butane by liquid volume, reducing said moisture content of said propane and said butane, reducing volatile impurities, and removing ethane from said propane and from said butane are performed on said propane and said butane individually and prior to blending said propane and said butane.

17. The method for replacing a hydrofluoro refrigerant in an air conditioning system with an instrument-grade hydrocarbon refrigerant gas of claim 12 wherein said steps of selecting said ratio of propane and butane by liquid volume, reducing said moisture content of said propane and said butane, reducing volatile impurities, and removing ethane from said propane and from said butane are performed subsequent to blending said selected ratio of said propane and said butane.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0010] The above-mentioned features of the invention will become more clearly understood from the following detailed description of the invention read together with the drawings in which:

[0011] FIG. 1 (Prior Art) is a schematic view of an exemplary state-of-the-art air conditioning system;

[0012] FIG. 2 is a schematic model of the molecular structure of propane;

[0013] FIG. 3 is a schematic model of the molecular structure of iso-butane;

[0014] FIG. 4 is a schematic model of the molecular structure of n-butane; and

[0015] FIG. 5 is a flow chart showing the steps of the method of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0016] The present invention is directed towards an instrument-grade, blended HC refrigerant gas that can be utilized in various air conditioning and/or chilling systems, such as the refrigerant systems in refrigerators, especially aerosol grade refrigerators, residential air conditioning systems, and the air conditioning systems utilized in motorized, hybrid, and electric vehicles, systems as a replacement for state-of-the-art Hydrofluro Refrigerants and that can be utilized in new chilling and air conditioning systems that require an instrument-grade refrigerant. In order to be useful as a refrigerant and be a suitable replacement for Hydrofluoro Refrigerants, a blended HC refrigerant must have a comparable boiling point. As is known in the art, at normal atmospheric pressure, the boiling point of R134a is approximately 26.3 C., (15.3 F.), and the boiling point of R1234yf is approximately 29.8 C., (21.6 F.). Further, it is known that the boiling point of propane, C.sub.3H.sub.8, see 10 in FIG. 1, at normal atmospheric pressure is approximately 42.1 C., (43.8 F.).

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[0017] Further, the boiling point of iso-butane, C.sub.4H.sub.10, see 20 in FIG. 2, at normal atmospheric pressure is approximately 11.7 C. (10.9 F.).

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[0018] Finally, the boiling point of n-butane, C.sub.4H.sub.10, see 30 in FIG. 3, at normal atmospheric pressure, is approximately 0.5 C., (31.1 F.).

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[0019] By blending refrigerant grade propane, R290, and refrigerant grade butane, either n-butane, R600, or iso-butane, R600a together, a suitable blended HC refrigerant gas, with a suitable boiling point, can be attained. Moreover, a blended HC refrigerant gas will produce less electrical draw on the MAC system than R134a, R1234fy, or other aerosol grade HFx Refrigerants.

[0020] Referring to FIG. 5, in order to replace an HFC such as R134a, whether for a new system or in an existing system, an HC gas blend of R290 and either R600 or R600a is created as in accordance with method 100. First, as at step 110, a ratio of blended HC gas is selected. In an exemplary embodiment, a blend of approximately 50% R290 to approximately 50% R600 or R600a is utilized. It will be appreciated that the percentages expressed herein are by liquid volume. While this is the preferred ratio, the acceptable range is approximately 50% to 80% R290 and approximately 20% to 50% of either R600 or R600A.

[0021] In order to replace an HFO, such as R1234yf, whether for a new system or in an existing system, an HC gas blend of R290 and either R600 or R600a is created as follows. In an exemplary embodiment, approximately 70% R290 is blended with approximately 30% either R600 or R600a. While this an exemplary ratio, the acceptable range is approximately 70% to 90% R290 and approximately 10% to 30% either R600 or R600A. Once the desired ratio is selected, the R290 and either R600 or R600A are blended at step 120.

[0022] With replacement of an HFx Refrigerant, either the HFC, R134a, or the HFO, R1234yf, the blended HC refrigerant gas is preferably instrument-grade and must meet AHRI 700 Standards for refrigerants, especially with regard to water and impurities. In this regard, the moisture content must be reduced below 5% and preferably below 10 mg/kg at step 130. Further, all other volatile impurities must be reduced below 0.5 percent by weight at step 140. Additionally, ethane must be removed at step 150. Those skilled in the art will recognize that these steps could be performed by means of a fractionator. Those skilled in the art will recognize that there are also other methods for removing ethane and for drying the blended HC refrigerant gas. Additionally, a drying agent could be added to the HC refrigerant gas blend. It will be appreciated that the step of drying and reducing water content to AHRI 700 Standard and removing ethane could be performed on the constituent HC gases prior to the step of blending the constituent HC gases or could be performed on the HC refrigerant gas blend. Finally, a non-conductive synthetic oil, such as Polyolester Oil is added at step 160 to lubricate the compressor of the air conditioning system. It should be understood that only a non-conductive POE oil should be utilized to provide for lubrication of the compressor.

[0023] In order to replace an aerosol grade HFx Refrigerant with the instrument-grade HC blend described herein, the aerosol grade HFx Refrigerant is carefully removed from the system with a reclaiming machine, at step 170, taking care not to release any of the aerosol grade HFx Refrigerant to the atmosphere. The instrument-grade blended HC refrigerant gas replacement is then injected into the system at step 180.

[0024] While the present invention has been illustrated by description of several embodiments and while the illustrative embodiments have been described in detail, it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of applicant's general inventive concept.