Integrated condensing heat exchanger and water separator, condensing heat exchanger and water separator, and environmental control system

Abstract

To provide an improved integrated condensing heat exchanger and water separator, an improved condensing heat exchanger and water separator, and an improved environmental control system.SOLUTION: An integrated condensing heat exchanger and water separator 28 includes a microporous graphite plate 48, one or more water passages defined at a first side 56 of the microporous graphite plate 48, and one or more air passages defined at a second side 58 of the microporous graphite plate 48 opposite the first side. An air inlet 38 is operably connected to the one or more air passages to direct a flow of air through the one or more air passages at a first pressure, and a water inlet 30 is operably connected to the one or more water passages to direct a flow of water through the one or more water passages at a second pressure lower than the first pressure. The microporous graphite plate 48 is configured such that moisture condenses from the flow of air onto the second side 58 and is brought through the microporous graphite plate 48 to the one or more water passages.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD OF THE INVENTION Exemplary embodiments relate to the art of environmental control systems, for example, for spacecraft. [Background technology]

[0002] Such environmental control systems typically include a temperature and humidity control system to provide a comfortable environment inside the spacecraft. A typical system architecture includes a fan that directs spacecraft cabin air through a condensing heat exchanger to remove moisture from the cabin air, and a separate rotary water separator to remove condensate from the cabin air stream. Rotary water separators rely on centrifugal force to separate water from the air stream and require significant power to operate. Furthermore, typical condensing heat exchangers are expensive to manufacture and have limited production, typically requiring long lead times. Summary of the Invention [Problem to be solved by the invention]

[0003] Accordingly, the present invention provides an improved integrated condensing heat exchanger and water separator, condensing heat exchanger and water separator, and environmental control system. [Means for solving the problem]

[0004] In one embodiment, the integrated condensing heat exchanger and water separator includes a microporous graphite plate, one or more water channels defined on a first side of the microporous graphite plate, and one or more air channels defined on a second side of the microporous graphite plate opposite the first side. An air inlet is operably connected to the one or more air channels to direct a flow of air through the one or more air channels at a first pressure, and a water inlet is operably connected to the one or more water channels to direct a flow of water through the one or more water channels at a second pressure lower than the first pressure. The microporous graphite plate is configured such that moisture condenses from the air flow onto the second side and is transported through the microporous graphite plate to the one or more water channels to join the water flow.

[0005] Additionally or alternatively, in this or other embodiments, the difference between the first pressure and the second pressure is maintained below the bubble point of the microporous graphite plate to prevent intrusion of air flow into one or more water passages through the microporous graphite plate.

[0006] Additionally or alternatively, in this or other embodiments, the second pressure is sub-ambient.

[0007] Additionally or alternatively, in this or other embodiments, the microporous graphite plate includes a plurality of first grooves on a first side to at least partially define one or more water channels and a plurality of second grooves on a second side to at least partially define one or more air passages.

[0008] In another embodiment, the condensing heat exchanger and water separator includes a plurality of microporous graphite plates arranged in a stack, each having one or more water channels defined on a first side of the microporous graphite plate and one or more air channels defined on a second side of the microporous graphite plate opposite the first side. An air inlet is operably connected to the one or more air channels to direct a flow of air through the one or more air channels at a first pressure, and a water inlet is operably connected to the one or more water channels to direct a flow of water through the one or more water channels at a second pressure lower than the first pressure. The plurality of microporous graphite plates are configured so that moisture condenses from the air flow onto the second side and is carried through the microporous graphite plates to the one or more water channels to join the water flow.

[0009] Additionally or alternatively, in this or other embodiments, each microporous graphite plate of the plurality of microporous graphite plates includes a plurality of first grooves on a first side to at least partially define one or more water channels and a plurality of second grooves on a second side to at least partially define one or more air passages.

[0010] Additionally or alternatively, in this or other embodiments, a cover plate is located on one or more of the first stack side and the second stack side of the stack of microporous graphite plates.

[0011] Additionally or alternatively, in this or other embodiments, the air outlet is operatively connected to one or more air passages for passing the conditioned air flow out of the condensing heat exchanger and the water separator.

[0012] Additionally or alternatively, in this or other embodiments, the difference between the first pressure and the second pressure is maintained below the bubble point of the microporous graphite plate to prevent intrusion of air flow into one or more water passages through the microporous graphite plate.

[0013] Additionally or alternatively, in this or other embodiments, the second pressure is equal to or less than ambient pressure.

[0014] In yet another embodiment, an environmental control system includes a liquid-liquid heat exchanger, a pump, and a condensing heat exchanger and water separator. The liquid-liquid heat exchanger, the pump, and the condensing heat exchanger and water separator are arranged in a serial configuration to define a water coolant loop through which a water flow circulates. The condensing heat exchanger and water separator include a microporous graphite plate, one or more water channels defined on a first side of the microporous graphite plate, and one or more air passages defined on a second side of the microporous graphite plate opposite the first side. An air inlet is operably connected to the one or more air passages to direct a flow of air through the one or more air passages at a first pressure, and a water inlet is operably connected to the one or more water channels to direct a flow of water through the one or more water passages at a second pressure lower than the first pressure. The microporous graphite plate is configured so that moisture condenses from the air flow onto the second side and is transported through the microporous graphite plate to the one or more water channels to join the water flow.

[0015] Additionally or alternatively, in this or other embodiments, the difference between the first pressure and the second pressure is maintained below the bubble point of the microporous graphite plate to prevent intrusion of air flow into one or more water passages through the microporous graphite plate.

[0016] Additionally or alternatively, in this or other embodiments, the second pressure is equal to or less than ambient pressure.

[0017] Additionally or alternatively, in this or other embodiments, the microporous graphite plate includes a plurality of first grooves on a first side to at least partially define one or more water channels and a plurality of second grooves on a second side to at least partially define one or more air passages.

[0018] Additionally or alternatively, in this or other embodiments, a vented bellows accumulator and a flow metering orifice are positioned along the cooling water loop to maintain a selected second pressure of the water flow.

[0019] Additionally or alternatively, in this or other embodiments, a bellows accumulator is positioned along the cooling water loop between the pump and the condensing heat exchanger and water separator.

[0020] Additionally or alternatively, in this or other embodiments, the temperature of the water stream is maintained by exchanging thermal energy with a coolant stream in a liquid-to-liquid heat exchanger.

[0021] Additionally or alternatively, in this or other embodiments, a water withdrawal line is fluidly connected to the cooling water loop, the water withdrawal line being configured to selectively remove water from the cooling water loop.

[0022] Additionally or alternatively, in this or other embodiments, the extraction pump is located along the water extraction line.

[0023] The following description should not be considered limiting in any way.With reference to the accompanying drawings, like elements are numbered alike. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 1 is a schematic diagram of one embodiment of an environmental control system. [Figure 2] FIG. 1 is a schematic diagram of an embodiment of an integrated condensing heat exchanger and water separator. [Figure 3A] FIG. 12 is a perspective view of one embodiment of multiple air passages. [Figure 3B] FIG. 12 is a perspective view of one embodiment of a plurality of water channels. DETAILED DESCRIPTION OF THE INVENTION

[0025] A detailed description of one or more embodiments of the disclosed apparatus and methods is presented herein by way of example, and not limitation, with reference to the figures.

[0026] Referring now to FIG. 1 , one embodiment of an environmental control system 10, for example for a spacecraft, is shown. The system 10 utilizes a water coolant loop 12 through which a water stream 14 is circulated by a pump 16. The temperature of the water stream 14 is maintained by passing the water stream 14 through a liquid-liquid heat exchanger 18. In the liquid-liquid heat exchanger 18, the water stream 14 exchanges thermal energy with a coolant stream 20 in a coolant loop 22, thus cooling the water stream 14. In some embodiments, the coolant stream 20 enters the liquid-liquid heat exchanger 18 at a coolant inlet 24 and exits the liquid-liquid heat exchanger 18 at a coolant outlet 26. In the embodiment shown, the pump 16 is located along the water coolant loop 12 downstream of the liquid-liquid heat exchanger 18, although in other embodiments, the pump 16 may be located upstream of the liquid-liquid heat exchanger 18.

[0027] A condensing heat exchanger (CHX) and water separator 28 is located along the cooling water loop 12, upstream of the liquid-liquid heat exchanger 18, in some embodiments. The water flow 14 enters the CHX and water separator 28 at a water inlet 30 and exits the CHX and water separator 28 at a water outlet 32. Similarly, a return air flow 34, for example from the vehicle cabin 36, enters the CHX and water separator 28 at an air inlet 38. The return air 34 is conditioned in the CHX and water separator 28 and exits as a conditioned air flow 40 at an air outlet 42. In some embodiments, the conditioned air flow 40 is sent to the vehicle cabin 36.

[0028] Referring now to the cross-sectional view of Figure 2, the CHX and water separator 28 is shown in greater detail. The CHX and water separator 28 includes a first cover plate 44 and a second cover plate 46 opposite the first cover plate 44, which are spaced apart. A plurality of microporous graphite plates 48 are stacked between the first cover plate 44 and the second cover plate 46. The cover plates 44, 46 and the microporous graphite plates 48 each have a plurality of grooves 50 defined therein, such that, when stacked, the grooves 50 define a plurality of passages. Such passages are either air passages 52 or water passages 54, depending on the medium flowing therethrough.

[0029] Thus, the CHX and water separator 28 has multiple alternating layers of air passages 52 and layers of water passages 54, with adjacent layers separated by microporous graphite plates 48. Each water passage 54 is fluidly connected to a water inlet 30 and a water outlet 32 ​​such that the water flow 14 is routed through the multiple water passages 54. Similarly, each air passage 52 is fluidly connected to an air inlet 38 and an air outlet 42 such that return air 34 is routed from the air inlet 38 into the multiple air passages 52, and conditioned air 40 is routed from the multiple air passages 52 to the air outlets 42. In some embodiments, the CHX and water separator 28 is in a counterflow configuration. Referring to FIG. 3a, in some embodiments, the multiple air passages 52 have a single-pass configuration, while as shown in FIG. 3b, the multiple water passages 54 have a multiple-pass configuration, such as three passes as shown. However, it should be understood that other numbers of passes may be utilized. The multi-pass configuration of the water channels 54 accelerates the velocity of the water therein, thereby increasing the heat transfer coefficient and reducing the likelihood of surface fouling.

[0030] 2, a pressure differential (ΔP) is maintained between the air flow and the water coolant flow, such that the air flow pressure at the air outlet 42 is greater than the coolant flow pressure at the water outlet 32. In some embodiments, the pressure differential is achieved by maintaining the coolant flow at or below ambient pressure, as described in more detail below. During operation, a flow of relatively humid return air 34 is delivered to the plurality of air passages 52 via the air inlet 38, and a flow of water 14 is introduced into the plurality of water passages 54 via the water inlet 30.

[0031] As the water stream 14 flows along the first side 56 of the microporous graphite plate 48 and the return air 34 flows along the second side 58 of the microporous graphite plate 48, moisture in the return air 34 condenses on the second side 58 of the microporous graphite plate 48. As the moisture condenses, the hydrophilic treatment of the microporous graphite plate 48 transports the condensed moisture into the multiple micropores of the microporous graphite plate 48. The condensed moisture 60 is forced into the multiple water channels 54 on the first side 56 of the microporous graphite plate 48. A differential pressure is maintained below the bubble point of the microporous graphite plate 48 to prevent intrusion of air flow through the microporous graphite plate 48 into the multiple water channels 54. The water stream 14 exits the CHX and water separator 28 at the water outlet 32, and the air stream exits the CHX and water separator 28 at the air outlet 42, now as conditioned air 40.

[0032] 3a, in some embodiments, the air passages 52 include offset passages 80. This prevents any entrainment of water droplets that have not yet been transported through the microporous layer into the airflow—the water droplets would strike the sidewalls of the passages and be transported into the porous material. This is primarily the case when the air-side surface of the heat exchanger is locally fouled, reducing its hydrophilic nature and making the surface somewhat hydrophobic—and therefore water is less able to transport through the microporous layer.

[0033] 1, system 10 further includes a vented bellows accumulator 62 and a flow metering orifice 64 located along cooling water loop 12 to maintain a selected differential pressure. In some embodiments, accumulator 62 and flow metering orifice 64 are located between pump 16 and CHX and water separator 28.

[0034] Water or condensate is periodically removed from the coolant loop 12 for treatment, for example, when needed for vehicle use or when the water level in the accumulator 62 reaches a selected threshold. A water withdrawal line 66 is connected to the coolant loop 12 for water removal. The water withdrawal line 66 includes a solenoid valve 68, a withdrawal pump 70, and a safety valve 72. When the solenoid valve 68 is opened and the withdrawal pump 70 is activated, water is forced along the water withdrawal line 66 and through the safety valve 72. When the desired amount of water has been removed from the coolant loop 12, the withdrawal pump 70 stops operating and the solenoid valve 68 is closed.

[0035] As described herein, the CHX and water separator 28 combines the functions of the CHX and water separator into a single passive component, thereby increasing the overall reliability of the environmental control system in which the CHX and water separator is included.

[0036] The term "about" is intended to include the degree of error associated with measurement of the particular quantity based on equipment available at the time of filing.

[0037] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that the terms "comprises" and / or "comprising," as used herein, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0038] While the present disclosure has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the disclosure without departing from the essential scope of the disclosure. Therefore, it is not intended that the disclosure be limited to the particular embodiment disclosed as the best mode contemplated for carrying out the disclosure, but rather that the disclosure will include all embodiments falling within the scope of the appended claims.

Claims

1. An integrated condensing heat exchanger and water separator, comprising: a microporous graphite plate; one or more water channels defined in a first side of the microporous graphite plate; one or more air passages defined on a second side of the microporous graphite plate opposite the first side; an air inlet operably connected to the one or more air passages for directing a flow of air through the one or more air passages at a first pressure; a water inlet operably connected to the one or more water passages for directing a flow of water through the one or more water passages at a second pressure lower than the first pressure; Equipped with an integrated condensing heat exchanger and water separator, wherein the microporous graphite plate is configured such that moisture from the air stream condenses onto the second side and is conveyed through the microporous graphite plate to the one or more water channels to join the water stream.

2. 2. The condensation heat exchanger and water separator of claim 1, wherein the difference between the first pressure and the second pressure is maintained below the bubble point of the microporous graphite plate to prevent intrusion of the air flow through the microporous graphite plate and into the one or more water channels.

3. 2. The condensing heat exchanger and water separator of claim 1, wherein the second pressure is below ambient pressure.

4. The microporous graphite plate is a plurality of first grooves on the first side for at least partially defining the one or more channels; a plurality of second grooves on the second side to at least partially define the one or more air passages; 10. The condensing heat exchanger and water separator of claim 1, comprising:

5. A condensing heat exchanger and a water separator, A plurality of microporous graphite plates arranged in a stack, each of the microporous graphite plates comprising: one or more water channels defined in a first side of the microporous graphite plate; one or more air passages defined on a second side of the microporous graphite plate opposite the first side; an air inlet operably connected to the one or more air passages for directing a flow of air through the one or more air passages at a first pressure; a water inlet operably connected to the one or more water passages for directing a flow of water through the one or more water passages at a second pressure lower than the first pressure; Equipped with a plurality of microporous graphite plates configured to allow moisture to condense from the air stream onto the second side and be conveyed through the microporous graphite plates to the one or more water channels to join the water stream;

6. Each of the plurality of microporous graphite plates is a plurality of first grooves on the first side for at least partially defining the one or more channels; a plurality of second grooves on the second side for at least partially defining the one or more air passages; 6. The condensing heat exchanger and water separator of claim 5, comprising:

7. 6. The condensing heat exchanger and water separator of claim 5, further comprising a cover plate disposed on one or more of a first stack side and a second stack side of the stack of microporous graphite plates.

8. 6. The condensing heat exchanger and water separator of claim 5, further comprising an air outlet operatively connected to the one or more air passages for exiting a flow of conditioned air from the condensing heat exchanger and water separator.

9. 6. The condensation heat exchanger and water separator of claim 5, wherein the difference between the first pressure and the second pressure is maintained below the bubble point of the microporous graphite plate to prevent intrusion of the air flow into the one or more water passages through the microporous graphite plate.

10. 6. The condensing heat exchanger and water separator of claim 5, wherein the second pressure is below ambient pressure.

11. 1. An environmental control system comprising: a liquid-liquid heat exchanger; A pump and a condensing heat exchanger and a water separator; Equipped with the liquid-liquid heat exchanger, the pump, and the condensing heat exchanger and water separator are arranged in a serial configuration to define a cooling water loop through which a flow of water circulates; The condensing heat exchanger and the water separator are a microporous graphite plate; one or more water channels defined in a first side of the microporous graphite plate; one or more air passages defined on a second side of the microporous graphite plate opposite the first side; an air inlet operably connected to the one or more air passages for directing a flow of air through the one or more air passages at a first pressure; a water inlet operably connected to the one or more water passages for directing a flow of water through the one or more water passages at a second pressure lower than the first pressure; Including, the microporous graphite plate is configured such that moisture from the air stream condenses on the second side and is carried through the microporous graphite plate to the one or more water channels to join the water stream.

12. 12. The environmental control system of claim 11, wherein a difference between the first pressure and the second pressure is maintained at or below a bubble point of the microporous graphite plate to prevent intrusion of the air flow into the one or more water passages through the microporous graphite plate.

13. The environmental control system of claim 11 , wherein the second pressure is below ambient pressure.

14. The microporous graphite plate is a plurality of first grooves on the first side for at least partially defining the one or more channels; a plurality of second grooves on the second side to at least partially define the one or more air passages; The environmental control system of claim 11 , comprising:

15. 12. The environmental control system of claim 11, further comprising a vented bellows accumulator and a flow metering orifice disposed along said cooling water loop to maintain said selected second pressure of said water flow.

16. 16. The environmental control system of claim 15, wherein the bellows accumulator is disposed along the cooling water loop between the pump and the condensing heat exchanger and water separator.

17. The environmental control system of claim 11 , wherein the temperature of the water stream is maintained by exchanging thermal energy with a coolant stream in the liquid-to-liquid heat exchanger.

18. The environmental control system of claim 11 , further comprising a water withdrawal line fluidly connected to the cooling water loop, the water withdrawal line configured to selectively remove water from the cooling water loop.

19. 20. The environmental control system of claim 18, further comprising a withdrawal pump disposed along the water withdrawal line.

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