HEAT PUMPS UTILIZING IONIC LIQUID DESICCANT

Abstract

An ionic liquid desiccant system utilizes an ionic liquid desiccant to draw moisture from a working fluid, such as air that flow into an enclosure, such as a home. The desiccant may be mixed with the working fluid or a separator that allows moisture transport therethrough may be configured between the ionic liquid desiccant and the working fluid. The ionic liquid desiccant system may be part of an air conditioning system and may remove the moisture from air that is cooled by flowing over an evaporator or heat exchanger coupled with the evaporator. The ionic liquid desiccant may be pumped from a desiccant chamber to a regenerator chamber to remove absorbed moisture. A dual-purpose chamber may act as a desiccant chamber and as a regenerator chamber. A refrigeration system may have an electrochemical compressor and may utilize metal hydride heat exchangers.

Claims

1. An air treatment system comprising: a) a desiccation system comprising: i) a desiccation chamber having: an inlet; and an outlet; ii) a liquid ionic desiccant that is at liquid at room temperature; iii) a working fluid that flows through said desiccation chamber from the inlet to the outlet and transfers working fluid moisture to the liquid ionic desiccant; wherein an inlet working fluid moisture concentration is greater than an outlet working fluid moisture concentration.

2. The air treatment system of claim 1, wherein the liquid ionic desiccant consists essentially of a cation and an anion, wherein that have steric hindrance to prevent crystallization at room temperature.

3. The air treatment system of claim 2, wherein the cation is an inorganic cation.

4. The air treatment system of claim 2, wherein the anion is an inorganic anion.

5. The air treatment system of claim 2, wherein the liquid ionic desiccant comprises no more than 20% of an additive.

6. The air treatment system of claim 5, wherein the additive is a salt.

7. The air treatment system of claim 1, wherein the liquid ionic desiccant is in direct contact with the working fluid in the desiccation chamber.

8. The air treatment system of claim 1, comprising a moisture separator that separates the liquid ionic desiccant from the working fluid in the desiccation chamber and wherein working fluid moisture is transferred across the moisture separator.

9. The air treatment system of claim 1, wherein the moisture separator has no bulk flow of gas.

10. The air treatment system of claim 9, wherein the moisture separator is an ionic transport membrane.

11. The air treatment system of claim 10, wherein the moisture separator comprises an ionomer.

12. The air treatment system of claim 1, wherein the desiccant chamber receives heat from a heating device and wherein said heat increases the temperature of the liquid ionic desiccant to reduce a liquid ionic desiccant moisture level.

13. The air treatment system of claim 12, wherein a flow of regenerator air flows through the desiccant chamber to carry away moisture from the liquid ionic desiccant while it is being heated.

14. The air treatment system of claim 12, wherein the air treatment system is an air conditioning system that further comprises a evaporator for reducing the temperature of the air.

15. The air treatment system of claim 14, wherein the air conditioning system comprises a condenser that creates heat and wherein the heat is in communication with a regenerator that contains the liquid ionic desiccant, and wherein the liquid ionic desiccant is regenerated by said heat, wherein an inlet liquid ionic desiccant moisture level is higher than an outlet liquid ionic desiccant moisture level as it passes through the regenerator.

16. The air treatment system of claim 15, wherein the liquid ionic desiccant is transferred from the desiccant chamber to the regenerator.

17. The air treatment system of claim 15, wherein the desiccant chamber receives heat from a heating device and wherein said heat increases the temperature of the liquid ionic desiccant to reduce a liquid ionic desiccant moisture level.

18. The air treatment system of claim 17, wherein a secondary flow of gas flows through the desiccant chamber to carry away moisture from the liquid ionic desiccant while it is being heated.

19. The air treatment system of claim 1, wherein the air treatment system is part of a) an electrochemical heat transfer device comprising: i) a working fluid comprising hydrogen; ii) a first electrochemical hydrogen compressor comprising: an anode; a cathode; a proton exchange membrane; iii) a power supply coupled to the anode and cathode to transfer the hydrogen across the proton exchange membrane; wherein the hydrogen flows through the desiccant chamber to reduce the working fluid moisture level.

20. The air treatment system of claim 1, wherein the electrochemical heat transfer device further comprises: a) a first gas containment chamber comprising a metal hydride; b) a first heat transfer device coupled to said first gas containment chamber; wherein moisture within the working fluid is absorbed by the liquid ionic desiccant; wherein the electrochemical hydrogen compressor transfers hydrogen to said first gas containment chamber and wherein hydrogen is absorbed by the metal hydride and heat is transferred to the heat exchange device; and wherein the electrochemical heat transfer device is a heating device.

21. The electrochemical heat transfer device of claim 20, wherein the liquid ionic desiccant is heated by the heat transfer device to drive absorbed moisture from the liquid ionic desiccant.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0043] 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.

[0044] FIG. 1 shows a diagram of an exemplary refrigeration system comprising an ionic liquid desiccant system configured to reduce the moisture content of air before entering the enclosure.

[0045] FIG. 2 shows a diagram of an exemplary refrigeration system comprising an electrochemical compressor.

[0046] FIG. 3 shows a diagram of an exemplary ionic liquid desiccant system having a desiccant chamber and a separate regenerator chamber.

[0047] FIG. 4 shows a diagram of an exemplary ionic liquid desiccant system having a chamber that acts as both a desiccant chamber and a regenerator chamber.

[0048] FIG. 5 shows an exemplary gas storage chamber of an electrochemical compressor system.

[0049] FIG. 6 shows an exemplary heat exchanger comprising a coil around a gas containment vessel.

[0050] FIG. 7 shows a diagram of an exemplary heat exchanger comprising a coil around a gas containment vessel.

[0051] FIG. 8 shows a diagram of an exemplary electrochemical heat exchanger system.

[0052] FIG. 9 shows a diagram of an electrochemical compressor.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

[0053] 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.

[0054] 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.

[0055] In cases where the present specification and a document incorporated by reference include conflicting and/or inconsistent disclosure, the present specification shall control.

Definitions

[0056] As used herein, the terms “vapor” and “vaporous” may be used interchangeably.

[0057] 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.

[0058] Referring to FIGS. 1 and 2, an exemplary refrigeration system 310 comprises a compressor 318 a condenser 316 and expansion valve 350 and an evaporator 315. The evaporator cools the air before it enters into an enclosure 190. A liquid ionic desiccant system 100 is configured to reduce the moisture content of the incoming air 301 into the desiccant chamber 103. The outlet air 302 from the desiccant chamber will have a lower moisture content than the incoming air. The air entering the enclosure 303 will be cool and dry. The enclosure shown is a home. Note that the desiccant chamber may be configured before or after the evaporator or cooling device. The compressor has a low pressure side 352 and a high pressure side 354. In FIG. 1, the compressor is a mechanical compressor and in FIG. 2 the compressor is an electrochemical compressor 312 comprising a membrane electrode assembly 314. The refrigeration system has a plurality of sensors 348, a controller 330 that may run a control program 356 on a microprocessor, for example. The desiccant chamber 103 comprises a liquid ionic desiccant 110 that absorbs moisture from the incoming air 301.

[0059] As shown in FIG. 3, an exemplary ionic liquid desiccant system 100 has a desiccant chamber 103 and a regenerator chamber 130. The ionic liquid desiccant 110 is separated from the desiccant chamber by a separator 150. The ionic liquid desiccant 110 is pumped by pump 112 from the desiccant chamber 103 to the regenerator chamber 130. The ionic liquid desiccant 110 is separated from the regenerator chamber 130 by a separator 150′. A working fluid 140, such as air circulated from or pumped into an enclosure 190 flows, through the desiccation chamber from the inlet to the outlet and transfers working fluid moisture to the liquid ionic desiccant. The inlet air 301 has an inlet working fluid moisture concentration that is greater than the outlet working fluid moisture concentration in the outlet air 302. The ionic liquid is pumped to the regenerator, wherein the moisture is transferred to a regenerator air 133, wherein the inlet regenerator air 131 has a lower moisture concentration than the outlet regenerator air 132. The regenerator air may be air from outside the enclosure, or it may be air from within the enclosure that is pumped from the enclosure, through the regenerator chamber and out from the desiccant system and the enclosure 190. A heating element 165, such as a condenser or heat exchanger coupled with a condenser may provide heat to the ionic liquid desiccant within the regenerator to heat it and drive off the moisture.

[0060] As shown in FIG. 4, an exemplary ionic liquid desiccant system 100 has a dual purpose chamber 138 that acts as a desiccant chamber 103 and a regenerator chamber 130. The ionic liquid desiccant 110 is separated from this dual purpose chamber by a separator 150. In a desiccant mode, a working fluid 140, such as air circulated from or pumped into an enclosure 190, flows through the desiccation chamber from the inlet to the outlet and transfers working fluid moisture to the liquid ionic desiccant 110. The inlet air 301 has an inlet working fluid moisture concentration that is greater than the outlet working fluid moisture concentration in the outlet air 302. The ionic liquid is pumped to the regenerator, wherein the moisture is transferred to a regenerator air 133, wherein the inlet regenerator air 131 has a lower moisture concentration than the outlet regenerator air 132. Valves 114 may close and valves 114′ may open to allow a regenerator air to flow through the dual-purpose chamber 138 and draw out moisture from the ionic liquid desiccant 110. A heating element 165, such as a condenser or heat exchanger coupled with the condenser of a refrigeration system act as the heating element 165. The cycle between desiccant mode and regeneration mode may alternate to provide a flow of dry air to the enclosure 190. The regenerator air may be from outside of the enclosure, such as from outside of the home. Note that the regenerator air may be any suitable type of gas, not simply ambient air from within the enclosure or from outside of an enclosure and may be nitrogen or some other gas that is specific for drawing out moisture from the ionic liquid desiccant.

[0061] As shown in FIG. 5, an exemplary desiccant chamber 103, comprises an enclosure 108 that comprises an interior 109 for the transfer of moisture from a working fluid 140, such as hydrogen, to an ionic liquid 110. The descant chamber has an inlet 102 and outlet 105 wherein the working fluid and ionic liquid are circulated into the interior 109.

[0062] FIG. 6 shows an exemplary metal hydride heat exchanger 67 has a metal hydride reservoir 40 and a heat exchange device 47. The metal hydride reservoir is a tube 79 that contains a metal hydride 43. The heat exchanger device 47 comprises a heat transfer conduit 76 that is coiled around the tube, or cylinder and a heat transfer fluid 82 passes through the conduit. The heat transfer device 47 also comprises a heat transfer conduit 83′ that is in direct communication with the metal hydride. As shown, the heat transfer conduit 83′ passes through the cylinder or tube, wherein the conduit is in direct contact with the metal hydride 43. The interior heat transfer conduit 76′ may be coiled around the interior of the cylinder to increase thermal conductivity. The heat transfer fluid may be a gas, or a liquid, such as water. Any suitable type of heat exchange fluid may be configured to flow through secondary loop as described herein

[0063] As shown in FIG. 7, an exemplary ionic liquid heat exchanger 100 comprises a coil 106 around a gas containment vessel 108. The gas containment vessel comprises an interior for the flow of a working fluid 140, such as hydrogen. A liquid, such as an ionic liquid 110 may flow through the coil to transfer heat to or from the gas containment chamber. An ionic liquid 110′ may flow through the interior of the containment vessel 109 and mix with the working fluid desiccate the working fluid 140, such as hydrogen. The containment vessel may be a desiccant chamber 103 and part of a desiccant system 101, when the working fluid transfers moisture to the ionic liquid therein.

[0064] Referring now to FIG. 8, an exemplary integrated electrochemical compressor and metal hydride heat exchanger 17 has a heat transfer fluid conduit 76 in thermal communication with the metal hydride reservoir 40. A first heat exchange conduit 76 may extend on the anode side of the cell and a second conduit may extend only on the cathode side of the cell stack 20 and a second heat exchange conduit 76 may extend on the cathode side of the cell. A heat conduit may extend over a plurality of the electrochemical cells 16, or down over the electrochemical stack. One heat exchange conduit may extend over the cells that are absorbing hydrogen and releasing heat, while the other may extend over, or be in thermal communication, with the cells that are desorbing hydrogen and conducting heat. A heat exchange conduit may extend from one side of a cell, the anode side, to a cathode side, especially when there are two or more cells, or a cell stack 20. Since the metal hydride reservoirs alternate between hot and cold, it is possible that a bipolar plate could be hot on one side and cold on another. It is therefore preferable for adjacent cells to alternate in polarity so that two hot sides, or two cathodes, are always adjacent to each other and the bipolar plate, as show in FIG. 24. Also, it is preferable that the plumbing of the heat exchange fluid alternate between adjacent cells so that it can draw the cool and hot side thermal transfers separately.

[0065] As shown in FIG. 9, an electrochemical compressor 21 comprises a fuel cell 14 having an anode 46, a ion conductive membrane 49 and a cathode 48. Water is introduced on the anode side 45 and is converted into protons, H.sup.+, that are transported across the ion conducting membrane 49 to the cathode side 47. A gas diffusion media 70, 70′ is configured in direct and electrical contact with the anode and cathode respectively. An exemplary fuel cell 14 comprises an electrochemical cell 20. The fuel cell comprises a membrane electrode assembly 42 comprising a proton conducting membrane 49, an anode 46 and cathode 48. A membrane electrode assembly may in some cases include a gas diffusion media 70, 70′. A flow field 72, 72′, typically comprising an electrically conductive plate having channels for the delivery of gasses to the surface of the membrane electrode assembly, is configured on either side of the membrane electrode assembly. The anode side 45 of the fuel cell converts hydrogen to protons, H.sup.+, which are then transported across the membrane to the cathode side 47. At the cathode, the protons react with oxygen to produce water and the water produced moves through the compressor outlet 52 and into conduit 50. This transfer, or pumping, of protons across the membrane produces an increased pressure on the cathode side. The anode side 45 is the low pressure side 43, and the cathode side 47 is the high pressure side 44 of the electrochemical compressor 20. The hydrogen inlet 40 and oxygen inlet 41 are shown

[0066] 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.