Electrochemical Compression of Ammonia Using Ion Exchange Membranes

Abstract

An electrochemical compressor utilizes a working fluid having a proton associable component, such as ammonia. Water may be reacted on a anode to form protons that are transported through an ion conducting membrane to the cathode side of the electrochemical compressor. The proton associable component of the working fluid will be pulled through the ion conducting membrane along with the proton. The ion conducting membrane may include perfluorosulfonic acid ionomer, polystyrene sufonic acid ionomer and/or carboxymethyl cellulose.

Claims

1. An electrochemical compressor comprising: a working fluid comprising: ammonia; and hydrogen; one or more electrochemical cells electrically connected to each other through a power supply, each electrochemical cell comprising: a gas pervious anode, a gas pervious cathode, an electrolyte disposed between and in intimate electrical contact with the cathode and the anode; a) an electrochemical compressor input for receiving aid working fluid; wherein the ammonia and hydrogen are transferred through the electrolyte from the anode to the cathode to create a high pressure side of the of the electrochemical cell.

2. The electrochemical compressor of claim 1, wherein the electrolyte is an ion conducting membrane.

3. The electrochemical compressor of claim 1, wherein the ion conducting membrane comprises perfluorosulfonic acid ionomer.

4. The electrochemical compressor of claim 1, wherein the ion conducting membrane comprises perfluorosulfonic acid ionomer.

5. The electrochemical compressor of claim 1, wherein the ion conducting membrane comprises polystyrene sulfonic acid ionomer.

6. The electrochemical compressor of claim 1, wherein the ion conducting membrane comprises carboxymethyl cellulose.

7. The electrochemical compressor of claim 1, wherein the ion conducting membrane consists essentially of polystyrene sulfonic acid ionomer.

8. The electrochemical compressor of claim 1, wherein the on conducting membrane consists essentially of carboxymethyl cellulose

9. A refrigeration system that conveys heat from a first heat reservoir at a relatively low temperature to a second heat reservoir at relatively high temperature, the refrigeration system defining a dosed loop that contains a working fluid, at least part of the working fluid being circulated through the dosed loop, the refrigeration system comprising: a first heat transfer device that transfers heat from the first heat reservoir to the working fluid, a second heat transfer device that transfers heat from the working fluid to the second heat reservoir, an expansion valve between the first and second heat transfer devices that reduces pressure of the working fluid, a conduit system and an electrochemical compressor between the first and second heat transfer devices; wherein the electrochemical compressor comprises: one or more electrochemical cells electrically connected to each other through a power supply, each electrochemical cell comprising: a gas pervious anode, a gas pervious cathode, an electrolyte disposed between and in intimate electrical contact with the cathode and the anode; an electrochemical compressor input, an electrochemical compressor output, wherein the working fluid comprises: a condensable refrigerant that essentially bypasses the electrochemical process and remains in the closed loop; and an electrochemically active fluid that participates in the electrochemical process within the electrochemical compressor; wherein said conduit system has a geometry that enables at least a portion of the received working fluid to be imparted with a gain in kinetic energy as it moves through the conduit system; wherein the working fluid comprising: ammonia; and hydrogen; wherein the ammonia is transferred through the electrolyte and through the conduit.

10. The refrigeration system of claim 9, wherein the electrolyte is an ion conducting membrane.

11. The refrigeration s steam of claim 9, wherein the ion conducting membrane comprises perfluorosulfonic acid ionomer.

12. The refrigeration system of claim 9, wherein the ion conducting membrane comprises perfluorosulfonic acid ionomer.

13. The refrigeration system of claim 9, wherein the ion conducting membrane comprises polystyrene sulfonic acid ionomer.

14. The refrigeration system of claim 9, wherein the ion conducting membrane comprises carboxymethyl cellulose.

15. The refrigeration system of claim 9, wherein the ion conducting membrane consists essentially of polystyrene sulfonic acid ionomer.

16. The refrigeration system of claim 9, wherein the ion conducting membrane consists essentially of carboxymethyl cellulose.

Description

BRIEF DESCRIPTION OF SEVERAL VIEW OF THE DRAWINGS

[0028] The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention, and together with the description serve to explain the principles of the invention.

[0029] FIG. 1 shows a diagram of an exemplary electrochemical compressor.

[0030] FIG. 2 shows a diagram of an exemplary electrochemical compressor refrigeration system comprising a membrane electrode assembly (MEA) comprising a electrochemical cell for producing a flow of pressurized working fluid.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

[0031] Corresponding reference characters indicate corresponding parts throughout the several views of the figures. The figures represent an illustration of some of the embodiments of the present invention and are not to be construed as limiting the scope of the invention in any manner. Further, the figures are not necessarily to scale, some features may be exaggerated to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.

[0032] As used herein, the terms “comprises,” “comprising, includes,” “including,” “has,” “having” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Also, use of “a” or “an” are employed to describe elements and components described herein. This is done merely for convenience and to give a general sense of the scope of the invention. This description should be read to include one or at least one and the singular also includes the plural unless it is obvious that it is meant otherwise.

[0033] Certain exemplary embodiments of the present invention are described herein and are illustrated in the accompanying figures. The embodiments described are only for purposes of illustrating the present invention and should not be interpreted as limiting the scope of the invention. Other embodiments of the invention, and certain modifications, combinations and improvements of the described embodiments, will occur to those skilled in the art and all such alternate embodiments, combinations, modifications and improvements are within the scope of the present invention.

[0034] As used herein, the term consists essentially of, as used to describe the ion conducting membrane means that the ion conducting polymer of the ion conducting membrane is at least 80% the polymer stated, and more preferably at least 90% and even more preferably at least 95% by weight of the ion conducting polymer portion of the ion conducting membrane, which does not include a support material, such as expanded PTFE.

[0035] Referring now to FIG. 1, an exemplary electrochemical compressor 21 and an electrochemical cell 14 comprising an electrolyte, an ion conducting membrane 49, disposed between the anode side 45 and cathode side 47 of the electrochemical cell. The working fluid 90 comprises ammonia and enters the electrochemical compressor through inlet 40. The hydrogen is reacted on the anode 46 to produce H+ ions, or protons, that are passed through the ion conducting membrane to the cathode 48, where they reform into hydrogen. The ammonia may associate protons to form ammonium NH4+ and be dragged through the ion conducting membrane. The cell further comprises a flow field 71 with flow channels 72 to distribute the working fluid to the anode and cathode, and a gas diffusion media 70. The gas diffusion media is porous to allow the transfer of gas and liquid to the electrodes. The anode chamber 43 is the lower pressure side of the electrochemical cell and the, cathode chamber 44 is a higher pressure side of the electrochemical cell. The working fluid inlet 40 to the anode side feeds in the working fluid which may include ammonia that is transported through a pump or refrigeration system before returning to the inlet 40. The outlet conduit 52 of the electrochemical cell is at a high pressure than the inlet 40. The membrane electrode assembly 42 includes the ion conducting membrane 49 as well as the anode 46 and cathode 48. The power supply 81 produces a voltage differential between the anode and cathode to drive the reactions that cause the working fluid to pass from the anode to the cathode.

[0036] FIG. 2 shows a diagram of an exemplary electrochemical compressor refrigeration system 80 comprising an electrochemical compressor 21 utilizing a membrane electrode assembly 82 (MEA), such as shown in FIG. 1. The electrochemical compressor uses a power supply 81 to create a flow of pressurized working fluid 90. The working fluid is transferred by the MEA to the high pressure side and to the condenser 84. The condensed working fluid is then transferred through conduits 85 to the expansion valve 86 and then to the evaporator 88. The working fluid then returns to the anode side, or low pressure side, of the electrochemical compressor.

[0037] It will be apparent to those skilled in the art that various modifications, combinations and variations can be made in the present invention without departing from the spirit or scope of the invention. Specific embodiments, features and elements described herein may be modified, and/or combined in any suitable manner. Thus, it is intended that the present invention cover the modifications, combinations and variations of this invention provided they come within the scope of the appended claims and their equivalents.