Integrated multi-stage heat exchanger and liquid desiccant regenerator and related methods

Abstract

A regeneration system includes: a liquid desiccant regeneration loop including a liquid desiccant tank and a heat and mass exchanger; and a refrigerant circuit including a first heating zone and a second heating zone, where a temperature in the first heating zone is higher than a temperature in the second heating zone. Low-concentration liquid desiccant in the liquid desiccant tank sequentially flows from the second heating area to the first heating area, then passes through the heat and mass exchanger and is stored as high-concentration liquid desiccant; and a portion of the low concentration liquid desiccant exiting the first heating zone or the second heating zone is used as a heating fluid for the heat and mass exchanger. A method of operating such a regeneration system is also provided.

Description

[0001] Source of Contract

[0002] This invention was completed with government support, pursuant to Contract No. DE-AC36-08GO28308 granted by the Department of Energy. The government holds certain rights to this invention.

[0003] Cross-reference to related applications

[0004] This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 584,433, filed September 21, 2023, the entire disclosure of which is expressly incorporated herein by reference. Technical Field

[0005] This disclosure generally relates to heat and mass exchange systems, such as those that can be used for the regeneration of liquid desiccants. Background Technology

[0006] Heat and mass exchangers are known to be used as liquid desiccant regenerators. The heat and mass exchanger both heats the liquid desiccant and provides an airflow to remove water vapor, converting low-concentration liquid desiccant into high-concentration liquid desiccant. Summary of the Invention

[0007] In some embodiments, a regeneration system is provided. The regeneration system may include: a liquid desiccant regeneration circuit including a liquid desiccant tank, a second heating zone, a first heating zone, and a heat and mass exchanger; and a heating circuit including the first heating zone and the second heating zone. In the regeneration system, the temperature in the first heating zone is higher than the temperature in the second heating zone; a low-concentration liquid desiccant in the liquid desiccant tank sequentially flows from the second heating zone to the first heating zone, then through the heat and mass exchanger, and is subsequently stored as a high-concentration liquid desiccant; and a portion of the low-concentration liquid desiccant leaving the first heating zone or the second heating zone is used as the heating fluid for the heat and mass exchanger.

[0008] In some embodiments, the regeneration system further includes a third heating zone. In some embodiments, both the liquid desiccant regeneration loop and the heating loop include the third heating zone, wherein the temperature in the first heating zone is higher than the temperature in the second heating zone, and the temperature in the second heating zone is higher than the temperature in the third heating zone. In some embodiments, low-concentration liquid desiccant in the liquid desiccant tank flows sequentially from the third heating zone to the second heating zone, then to the first heating zone, then through the heat mass exchanger, and then returns to the liquid desiccant tank as high-concentration liquid desiccant. In some such embodiments, a portion of the low-concentration liquid desiccant leaving the second heating zone is used as a first heating fluid for the heat mass exchanger; and wherein a portion of the low-concentration liquid desiccant leaving the third heating zone is used as a second heating fluid for the heat mass exchanger.

[0009] In another aspect, a regeneration system capable of operating in an evaporator coil anti-frost mode is provided, the regeneration system comprising: a liquid desiccant regeneration circuit including a liquid desiccant tank, a heating zone, and a heat mass exchanger; and a refrigerant circuit including a heating zone, an expansion valve, an evaporator, and a compressor. In these regeneration systems, a first portion of the liquid desiccant in the liquid desiccant tank flows into the heat mass exchanger and then returns to the liquid desiccant tank; regeneration air passes through the heat mass exchanger, wherein the first portion of the liquid desiccant flowing in the heat mass exchanger dehumidifies the regeneration air to form a dehumidified exhaust stream, and the dehumidified exhaust stream is fed to the evaporator to reduce the presence of frost on the evaporator coils of the evaporator.

[0010] In another aspect, a method of operating a regeneration system is provided, the method comprising: heating a low-concentration liquid desiccant; and causing a first portion of the heated low-concentration liquid desiccant to flow through a heat mass exchanger to produce a high-concentration liquid desiccant, wherein a second portion of the heated low-concentration liquid desiccant is used to remove moisture from the first portion of the low-concentration liquid desiccant within the heat mass exchanger. Attached Figure Description

[0011] The following figures illustrate specific embodiments of the present disclosure and are therefore not intended to limit the scope of the disclosure. The figures are not drawn to scale and are intended to be used in conjunction with the explanations in the following detailed description.

[0012] Figure 1 This illustrates a regeneration system comprising first and second heating zones as described herein;

[0013] Figure 2 This illustrates a second regeneration system comprising first and second heating zones as described herein;

[0014] Figure 3 This illustrates a third regeneration system comprising first and second heating zones as described herein;

[0015] Figure 4 This illustrates a regeneration system comprising first, second, and third heating zones as described herein;

[0016] Figure 5 A second regeneration system, comprising first, second, and third heating zones as described herein, is shown, having two liquid desiccant regeneration tanks;

[0017] Figure 6 A third regeneration system, comprising first, second, and third heating zones as described herein, is shown, having a distribution feed pipe;

[0018] Figure 7 A fourth regeneration system, as described herein, comprising first, second, and third heating zones, is shown, having a distribution feed pipe connected to a unit operation requiring a radiator;

[0019] Figure 8 A regeneration system comprising first, second, and third heating zones, as described herein, is shown, operating in heating mode;

[0020] Figure 9 The regeneration system, comprising first, second, and third heating zones as described herein, is shown, operating in evaporator coil anti-frost mode;

[0021] Figure 10 To illustrate the fluid temperature versus enthalpy curves of liquid desiccant and refrigerant as they flow through the first, second, and third heating zones as described herein;

[0022] Figure 11 A heat exchanger comprising first, second, and third heating zones as described herein is shown; and

[0023] Figure 12 A simplified regeneration system capable of operating in evaporator coil anti-frost mode according to some embodiments described herein is shown.

[0024] Figure 13 The present invention illustrates a regeneration system according to some embodiments described herein, the regeneration system operating using a regenerative heat and mass exchanger, an integrated shell and tube heat exchanger, a stratified tube, and a cold climate heat pump.

[0025] Figure 14 The present invention illustrates a regeneration system according to some embodiments described herein, the regeneration system operating using a regenerative heat and mass exchanger, an integrated shell and tube heat exchanger, and a cold climate heat pump.

[0026] Figure 15 The present invention illustrates a regeneration system according to some embodiments described herein, the regeneration system using refrigerant to air subcooling, a regenerative heat mass exchanger, an integrated shell and tube heat exchanger, and a cold climate heat pump. Detailed Implementation

[0027] The following discussion omits or only briefly describes conventional features of heat and mass exchangers that will be obvious to those skilled in the art. It should be noted that various embodiments are described in detail with reference to the accompanying drawings, wherein the same reference numerals denote the same parts and components in several views. Reference to the various embodiments does not limit the scope of the appended claims. Furthermore, any examples set forth in this specification are non-limiting and merely illustrate some of the many possible embodiments of the appended claims. Moreover, specific features described herein can be used in various possible combinations and arrangements with other described features.

[0028] Unless otherwise expressly defined herein, all terms shall be given the broadest reasonable interpretation, including the meaning implied in the specification, the meaning understood by a person skilled in the art, and / or the meaning defined in dictionaries, monographs, etc. It must also be noted that, as used in the specification and appended claims, unless otherwise stated, the singular forms “a” and “described” include plural indicators; and when used in this specification, the terms “comprising” and / or “including” indicate the presence of the said feature, element, and / or component, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. In the specification, relative terms such as “horizontal,” “vertical,” “upward,” “downward,” “top,” and “bottom,” and their derivatives (e.g., “horizontally,” “downward,” “upward,” etc.) shall be interpreted as referring to the orientation described or shown in the figures discussed. These relative terms are for ease of description and are not generally intended to require a specific orientation. The terms “above” and “below,” “inward” and “outward,” “longitudinal” and “lateral,” etc., shall be interpreted as appropriate relative to each other or relative to an axis of extension or axis of rotation or center of rotation. Terms involving attachment, connection, etc. (such as “connection” and “interconnection”) refer to a relationship in which structures are directly or indirectly fixed or attached to each other, either through an intermediate structure, as well as movable or rigid attachments or relationships, unless otherwise explicitly described. The terms “operationally connected”, “operably connected,” etc., refer to attachments, connections, or links that allow the relevant structures to function as intended under that relationship.

[0029] As shown in the figure, embodiments of this disclosure generally relate to a regeneration system 10, which includes a liquid desiccant regeneration loop 12 and a heating loop 18. The regeneration loop 12 includes a liquid desiccant (LD) tank 14, a second heating zone 22, a first heating zone 20, and a heat mass exchanger (HMX) 16. The heating loop 18 includes a first heating zone 20 and a second heating zone 22, wherein the temperature in the first heating zone 20 is higher than the temperature in the second heating zone 22. Low-concentration liquid desiccant in the liquid desiccant tank 14 flows sequentially from the second heating zone 22 to the first heating zone 20, then flows through the heat mass exchanger 16, and is subsequently stored in the LD tank 14 as high-concentration liquid desiccant. Additionally, a portion of the low-concentration liquid desiccant leaving the first heating zone 20 or the second heating zone 22 is used as a heating fluid in the heat mass exchanger 16. In some embodiments, after said portion of the low-concentration liquid desiccant has been used as a heating fluid, the low-concentration liquid desiccant is returned to one of the heating zones 20 and 22.

[0030] In some embodiments, such as Figure 4 As shown, high-concentration liquid desiccant and low-concentration liquid desiccant are stored in two different LD containers (high-concentration container 14A and low-concentration container 14B).

[0031] In some embodiments, such as Figure 1-3 and Figure 5-8 As shown, high-concentration liquid desiccant and low-concentration liquid desiccant are stored in the same tank 14. In such a tank, the tank is stratified, with the high-concentration liquid desiccant accumulating towards the bottom of the tank and the low-concentration liquid desiccant accumulating towards the top of the tank. The term LD tank 14 includes both dual tanks 14A / 14B and a single stratified tank 14.

[0032] The heat and mass exchanger 16 includes an HMX core 30 and may also include an evaporating medium section 32, a regenerated air heater 46, or both.

[0033] As shown in the figure, the HMX core 30 brings regenerated air 26 into contact with heated low-concentration liquid desiccant exiting the first heating zone 20. The HMX core 30 includes a plurality of HMX heat transfer tubes 34 adapted to contain a heating fluid (e.g., low-concentration liquid desiccant from one of the first, second, or third heating zones 20, 22, 24) internally and heat the low-concentration liquid desiccant flowing within the HMX core 30 but outside the HMX heat transfer tubes 34 (e.g., low-concentration liquid desiccant forming the LCLD feed stream 42 fed through distributor 29). The heat inside the HMX core 30 drives moisture from the low-concentration liquid desiccant into the regenerated air stream 26, forming an exhaust stream 38 exiting the HMX core 30 and a high-concentration liquid desiccant stream 28.

[0034] When present, the evaporation medium section 32 contains an evaporation medium 40, such as CELdek (sold by Cooling Media). In some embodiments, liquid desiccant exiting the HMX core 30 passes through the evaporation medium 40 and comes into contact with the regenerated airflow 26. The liquid desiccant is collected and exits the evaporation medium section 32 as a high-concentration liquid desiccant 28, which is returned to the liquid desiccant tank 14 or 14A.

[0035] When present, the regeneration heater 46 is adapted to heat the regeneration air 26 before it is fed to the evaporating medium section 32 or the HMX core 30.

[0036] In some embodiments, such as Figure 1-9 As shown, a low-concentration liquid desiccant (LCLD) feed stream 42, having exited the first heating zone 20, is fed into the heat and mass exchanger 16, where it comes into contact with the regenerated air stream 26 and is heated by the HMX heat transfer tube 34. In some embodiments, the liquid desiccant exits the heat and mass exchanger 16 as a high-concentration liquid desiccant stream 28. In some embodiments, a dispenser 29 feeds the LCLD feed stream 42 into the HMX core 30. In some embodiments, the dispenser 29 may be one or more sprayers or droppers.

[0037] In some embodiments, a portion of the low-concentration liquid desiccant leaving the first or second heating zone flows into the HMX heat transfer tube 34 in the heat mass exchanger 16. In some such embodiments, the HMX heat transfer tube 34 is adapted to heat the LCLD feed stream 42 regenerated within the heat mass exchanger 16.

[0038] In some embodiments, such as Figure 3 As shown, a portion of the low-concentration liquid desiccant leaving the first heating zone 20 flows within the HMX heat transfer tube 34 in the heat mass exchanger 16. In some such embodiments, a portion of the low-concentration liquid desiccant leaving the HMX heat transfer tube 34 returns to the first heating zone 20.

[0039] In some embodiments, such as Figure 1 As shown, a portion of the low-concentration liquid desiccant exiting the second heating zone 22 flows within the HMX heat transfer tube 34 in the heat mass exchanger 16. In some such embodiments, a portion of the low-concentration liquid desiccant exiting the HMX heat transfer tube 34 returns to the second heating zone 22.

[0040] In some embodiments, such as Figure 2 and 3As shown, a portion of the low-concentration liquid desiccant exiting the second heating zone 22 flows within the regeneration air heating tube 44 (e.g., a finned heating coil) to heat the regeneration air flow 26 before it is fed to the HMX core 30 or the evaporation medium section 32. The regeneration air heater 46 can be a heat exchanger, wherein the regeneration air flow 26 flows outside the regeneration air heating tube 44. In some such embodiments, the low-concentration liquid desiccant exiting the regeneration air heating tube 44 returns to the second heating zone 22.

[0041] In some such embodiments, once the heated regenerated air stream 26 leaves the regenerated air heater 46, it flows into the HMX core 30 and / or the evaporation medium section 32, contacts the LCLD feed stream 42 within the heat and mass exchanger 16, and exits as exhaust 38. In some embodiments, the heated regenerated air 26 contacts the LCLD feed stream 42 in the HMX core 30. In some embodiments, the heated regenerated air 26 contacts the LCLD feed stream 42 in the evaporation medium section 32.

[0042] exist Figure 3 In some embodiments, a portion of the low-concentration liquid desiccant leaving the first heating zone 20 flows within the HMX heat transfer tube 34 in the HMX core 30, and the HMX heat transfer tube 34 is adapted to heat the low-concentration liquid desiccant regenerated within the HMX core 30. In such embodiments, the low-concentration liquid desiccant leaving the HMX heat transfer tube 34 returns to the first heating zone 20.

[0043] In some embodiments, the first heating zone 20 and the second heating zone 22 are part of the same heat exchanger. In some embodiments, the first heating zone 20 and the second heating zone 22 are part of different heat exchangers.

[0044] In some embodiments, such as Figure 4-9 As shown, the regeneration system 10 includes a third heating zone 24. Figure 4-7 The diagram shows a regeneration system 10 operating in regeneration mode, while... Figure 8 and 9 The regeneration system 10 is shown in both heating mode and evaporator coil anti-frost mode.

[0045] In some embodiments, the heating circuit 18 includes a third heating zone 24, wherein the temperature in the first heating zone 20 is higher than the temperature in the second heating zone 22, and the temperature in the second heating zone 22 is higher than the temperature in the third heating zone 24. In some such embodiments, a low-concentration liquid desiccant in the liquid desiccant tank 14 / 14B flows sequentially to the third heating zone 24, then to the second heating zone 22, then to the first heating zone 20, then through the heat mass exchanger 16, and then returns to the liquid desiccant tank 14 / 14A as a high-concentration liquid desiccant stream 28. In some embodiments, a portion of the low-concentration liquid desiccant leaving the second heating zone 22 is used as a first heating fluid 56 for the heat mass exchanger 16 (e.g., HMX core 30), and a portion of the low-concentration liquid desiccant leaving the third heating zone 24 is used as a second heating fluid 58 for the heat mass exchanger 16 (e.g., regenerated air heater 46).

[0046] In some embodiments, the low-concentration liquid desiccant exiting the first heating zone 20 is used as the LCLD feed stream 42, which is fed into the heat and mass exchanger 16 and contacts the regenerated air stream 26, then exits the heat and mass exchanger 16 as a high-concentration liquid desiccant stream 28. Specifically, the LCLD feed stream 42 is fed into the heat and mass exchanger 16 via a distributor 29. The LCLD feed stream 42 may be fed into the HMX core 30. In some embodiments, the distributor 29 may be one or more atomizers or droppers.

[0047] In some embodiments, a first heating fluid 56 flows within an HMX heat transfer tube 34 in the HMX core 30, and the HMX heat transfer tube 34 is adapted to heat a low-concentration liquid desiccant regenerated within the HMX core. Specifically, the first heating fluid 56 flows inside the HMX heat transfer tube 34, while the LCLD feed stream 42 flows outside the HMX heat transfer tube 34 and contacts the regeneration air stream 26. In some embodiments, the first heating fluid 56 is then returned to the second heating zone 22.

[0048] In some embodiments, a second heating fluid 58 flows within the regenerated air heating tube 44 to heat the regenerated air 26 fed to the heat mass exchanger 16. The heated regenerated air 26 then flows within the heat mass exchanger 16 and contacts a low-concentration liquid desiccant within the heat mass exchanger 16 before exiting as exhaust 38 from the HMX core 30. Specifically, the heated regenerated air 26 contacts the low-concentration liquid desiccant within the HMX core 30 and the evaporation medium section 32 (if present). In some embodiments, the second heating fluid 58 then returns to the third heating zone 24.

[0049] In some embodiments, the first heating fluid 56 exits the second heating zone 22, then flows through the HMX heat transfer tube 34, then serves as the second heating fluid 58, and flows through the regenerated air heating tube 44 before returning to the third heating zone 24. In such embodiments, the second heating fluid 58 is not obtained from the third heating zone 24. In some such embodiments, a portion of the first heating fluid 56 may return to the second heating zone 22, while another portion of the first heating fluid 56 may be used as the second heating fluid 58 before returning to the third heating zone 24.

[0050] In the regenerated air heater 46, regenerated air 26 flows outside the regenerated air heating tube 44. Then, in the evaporator medium section 32 and the heat mass exchanger 16, the regenerated air 26 receives water vapor from the low-concentration liquid desiccant to form exhaust flow 42.

[0051] In some embodiments, after being used as a heating fluid, the first heating fluid 56 and the second heating fluid 58 are independently returned to one of the first, second, or third heating zones 20, 22, 24. In some embodiments, such as Figure 4-7 As shown, the first heating fluid 56 returns to the second heating zone 22, and the second heating fluid 58 returns to the third heating zone 24.

[0052] The regeneration system 10 described herein can be connected to a dehumidification system 60 that consumes liquid desiccant. Dehumidification can be part of an air conditioning system (e.g., the regulator of an LD air conditioning system) or any other operation suitable for consuming a high concentration of liquid desiccant to dehumidify the airflow.

[0053] The liquid desiccant tank 14 can be connected to the dehumidification system 60. In particular, a high-concentration liquid desiccant 62 can be fed into the dehumidification system 60, which returns a low-concentration liquid desiccant 64.

[0054] In some embodiments, such as Figure 5 As shown, high-concentration liquid desiccant 62 can come from high-concentration tank 14A, while low-concentration desiccant 64 is returned to low-concentration tank 14B.

[0055] In some embodiments, such as Figure 6 As shown, the high-concentration liquid desiccant 62 can originate from the bottom of the liquid desiccant tank 14, while the low-concentration desiccant 64 returns to the top of the liquid desiccant tank 14. In such an embodiment, the tank 14 is a stratified tank, wherein the high-concentration liquid desiccant 62 sinks to the bottom of the tank 14, while the low-concentration liquid desiccant 64 remains at the top of the tank 14.

[0056] In some embodiments, such as Figure 6As shown, the dispenser 29 can be one or more droppers. The droppers can be similar to the HMX heat transfer tube 34, except that they include openings for feeding the LCLD feed stream 42 into the HMX core 30. In some embodiments, the dispenser 29 is positioned above the HMX heat transfer tube 34.

[0057] In some embodiments, the first heating zone 20, the second heating zone 22, and the third heating zone 24 are part of the same heat exchanger. For example, the first, second, and third heating zones 20, 22, and 24 may be part of a large heat exchanger, wherein the first and second heating fluids 56 and 58 may originate from feed lines at different levels and temperatures along the length of the heat exchanger (e.g., the first heating fluid originates upstream of the second heating fluid). Figure 11 An example of such a heat exchanger is shown, which can be used as Figure 4-9 Heating zones 20, 22, and 24 are included. As can be seen, liquid desiccant from liquid desiccant tank 14 can enter an integral heat exchanger 19, which heats the liquid desiccant in third heating zone 24. A portion of the liquid desiccant reaching the range of third heating zone 24 can be supplied to regenerated air heating pipe 44 before returning to the starting point of third heating zone 24. Another portion of the liquid desiccant reaching the range of third heating zone 24 continues into second heating zone 22 (horizontal arrow).

[0058] A portion of the liquid desiccant reaching the second heating zone 22 may be supplied to the HMX heat transfer tube 34 before returning to the starting point of the second heating zone 22. Another portion of the liquid desiccant reaching the second heating zone 22 will continue into the first heating zone 20 (horizontal arrow).

[0059] Finally, the liquid desiccant reaching the first heating zone 20 is fed to the LD diversion circuit valve 68. At this point, the heated liquid desiccant will be guided toward the distributor 29 or the liquid desiccant diversion circuit 66.

[0060] In some embodiments, the first heating zone 20, the second heating zone 22, and the third heating zone 24 are part of different heat exchangers.

[0061] In some embodiments, such as Figure 1-6 8 and 9, heating circuit 18 is a refrigerant circuit in which refrigerant flows. In such an embodiment, heating circuit 18 may include compressor 48, which is adapted to convert gaseous refrigerant into hot refrigerant for heating zones 20, 22, and 24.

[0062] In some such embodiments, the heating circuit 18 includes an expansion valve 50 in which the liquid refrigerant expands into a gas. It is understood that the expansion process causes the cold gas to exit the expansion valve 50.

[0063] In some embodiments, the refrigerant circuit 18 includes an evaporator 52 following the expansion valve 50. In some such embodiments, the exhaust stream 38 exiting the heat exchanger 16 contacts the refrigerant in the evaporator 52 before being released from the regeneration system 10. Specifically, the refrigerant in the refrigerant circuit 18 flows within the evaporator tube 70 (e.g., a radiator), and the exhaust stream 38 is cooled as it flows through the evaporator tube 70. Thus, the evaporator 52 cools the hot exhaust stream 38 before it is released from the regeneration system (e.g., to the atmosphere).

[0064] In some embodiments, for each present component, the refrigerant in the refrigerant circuit 18 may flow through the compressor 48, then through the first heating zone 20, then through the second heating zone 22, then (if present) through the third heating zone 24, then through the expansion valve 50, then through the evaporator 52, and finally back to the compressor 48. It should be noted that additional components may be present in the refrigerant circuit 18, and these additional components may be suitably positioned between the aforementioned components 48, 20, 22, 24, 50, and 52. Additional components that may be included in the refrigerant circuit 18 include, but are not limited to, filter dryers, accumulators, diverter valves, three-way valves, sight glasses, pressure and temperature sensors, heat exchangers, and Schrader valves.

[0065] In some embodiments, such as Figure 7 As shown, heating circuit 18 includes unit operation 54 using heating zones 20, 22, and 24 as heat sinks. In such an embodiment, heating circuit 18 is used to cool unit operation 54, while heated fluid exiting unit operation 54 heats a low concentration of liquid desiccant in the first, second, and third heating zones 20, 22, and 24. In such an embodiment, heating circuit 18 can use a refrigerant that does not require a phase change. For example, the refrigerant can be water, propylene glycol, ethylene glycol, or mixtures thereof. In such an embodiment, as... Figure 7 As shown, heating circuit 18 may not include a compressor, expansion valve, and evaporator. Examples of unit operation 54 that can be used in such embodiments include, but are not limited to, condensers in industrial processes, fuel cells, solar cells, and other HVAC systems such as chillers.

[0066] Figure 10The diagram shows the fluid temperature versus enthalpy of the refrigerant in the heating circuit 18, which includes the first, second, and third heating zones 20, 22, and 24, as well as the fluid temperature versus enthalpy of the low-concentration liquid desiccant. The top line from right to left shows the temperature of the refrigerant in the heating circuit 18 as it passes through the first, second, and third heating zones 20, 22, and 24, while the bottom line from left to right shows the temperature of the low-concentration liquid desiccant as it passes through the third, second, and first heating zones 24, 22, and 20.

[0067] In some embodiments, the refrigerant in the heating circuit 18 is desuperheated in the first heating zone 20, then condensed in the second heating zone 22, and subcooled in the third heating zone 24. The maximum heat transfer will occur due to the phase change that takes place during the condensation phase (intermediate section), which typically occurs primarily in the second heating zone 22. It should be understood that, depending on the size of the heating zone and the initial temperatures of the refrigerant and the low-concentration liquid desiccant, desuperheating, condensation, and subcooling do not necessarily occur in only one heat exchanger (this may differ from a single physical heat exchanger when multiple heat exchangers are used).

[0068] In addition to the above-mentioned liquid desiccant regeneration modes, Figure 1-6 The regeneration system 10 of 8 and 9 can also operate in an alternative mode. For example, Figure 8 The regeneration system 10 is shown operating in heating mode, while Figure 9 The regeneration system 10 is shown operating in evaporator coil anti-frost mode. The regeneration system is shown in gray. Figure 8 and Figure 9 The components not used in the alternative operating modes described herein. However, once the regeneration system 10 is operating in regeneration mode, the components shown in gray will be used.

[0069] like Figure 8As shown, when the regeneration system 10 is operating in heating mode, no liquid desiccant flows to the heat mass exchanger 16. All valves and / or pumps that allow liquid desiccant to flow to the heat mass exchanger 16 are closed or stopped. Therefore, the liquid desiccant leaving the first heating zone 20 flows back to the liquid desiccant tank 14 via the LD diversion loop 66. In some embodiments of the regeneration mode, the LD diversion loop valve 68 is turned so that liquid desiccant does not flow through the LD diversion loop 66 (e.g., liquid desiccant is fed to the heat mass exchanger 16). In heating mode, the liquid desiccant flowing through the diversion loop 66 returns to the LD tank 14 at a higher temperature than when it leaves the tank at 12. In some embodiments, the heated liquid desiccant 62' in the liquid desiccant tank 14 is fed as a heated flow to the heater component 72 (e.g., a heating fluid for air conditioning) and then returned as cooled liquid desiccant 64'. In some embodiments, the heater component 72 may be a regulator for the dehumidification system 60. Additionally, when LD tank 14 is exposed to low temperatures (e.g., in winter), the heating mode may help prevent pipe blockage.

[0070] Therefore, during heating mode operation, heating circuit 18 operates normally, while liquid desiccant flows from liquid desiccant tank 14 through the third (if present), second and first heating zones 24, 22, 20, and then returns to liquid desiccant tank 14.

[0071] like Figure 9 and 12 As shown, the regeneration system 10 includes a liquid desiccant regeneration circuit 12 and a refrigerant circuit 18. The liquid desiccant regeneration circuit 12 includes a liquid desiccant tank 14, a heating zone 20, and a heat and mass exchanger 16. The refrigerant circuit 18 includes a heating zone 20, an expansion valve 50, an evaporator 52, and a compressor 48. A first portion of the liquid desiccant in the liquid desiccant tank 14 flows to the heat and mass exchanger 16 before returning to the liquid desiccant tank 14. Additionally, regeneration air 26 passes through the heat and mass exchanger 16, where the first portion of the liquid desiccant flowing in the heat and mass exchangers 16 dehumidifies the regeneration air 26 to form a dehumidified exhaust stream 38. This dehumidified exhaust stream 38 is fed to the evaporator 52 to reduce or eliminate the presence of frost on the evaporator coil 70.

[0072] In some embodiments, a second portion of the liquid desiccant flows to the heating zone 20 and then returns to the liquid desiccant tank 14, instead of being fed into the heat and mass exchangers 16, 30. In some embodiments, the second portion of the liquid desiccant is larger than the first portion of the liquid desiccant.

[0073] In some embodiments, a first portion of the liquid desiccant passes through at least one heating zone 20, 22, 24 before being fed to the heat mass exchanger 16 (e.g., HMX core 30). In other embodiments, the first portion of the liquid desiccant flows directly to the heat mass exchanger 16 (e.g., HMX core 30) through the heater branch loop 74. In some embodiments, it may be advantageous to cool (rather than heat) the liquid desiccant to facilitate dehumidification of the regenerated air 26 in the heat mass exchanger 16.

[0074] like Figure 9 As shown, the regeneration system 10 can operate in an evaporator coil anti-frost mode, a variant of the heating mode described above. When operating in evaporator coil anti-frost mode, a reduced amount of liquid desiccant is fed into the HMX core 30 via distributor 29. In this operating mode, the liquid desiccant is used to dehumidify the regeneration airflow 26 before it passes through the evaporator 52. Dehumidification can be facilitated when distributor 29 is a multi-atomizer or dropper. In some embodiments, such as Figure 9 As shown by the dashed line 74, a low-concentration liquid desiccant is diverted from one or more of the first, second, or third heating zones 20, 22, 24 such that the temperature of the liquid desiccant is insufficient for regeneration when it enters the heat mass exchanger (HMX) 16 through the distributor 29, and the HMX 16 operates as a dehumidifier (e.g., exhaust flow 38 is dehumidified air).

[0075] The defrosting mode can also be enhanced by heating the refrigerant flowing through the evaporator coil 70. Therefore, in some embodiments, the flow direction in the heating circuit 18 is reversed so that the hot refrigerant leaves the compressor 48 and flows through the evaporator 52 before passing through the expansion valve. This helps melt any ice that forms on the evaporator coil 70, while the dehumidified exhaust flow 38 carries the resulting moisture into the environment. In the above embodiments, the evaporator coil defrosting mode can be used to prevent ice buildup on the evaporator coil 70 when outdoor temperatures are low.

[0076] The anti-frost mode can also be implemented using the regeneration system 100, which is connected to... Figure 9 The system is simplified compared to the previous one. For example, such as Figure 12As shown, such a regeneration system 100 may include a heat exchanger comprising a first heating zone 20, which is part of a heating circuit 18, including an expansion valve 50, an evaporator 52, and a compressor 48. The regeneration system 100 may also include an LD regeneration circuit 12, which includes a liquid desiccant tank 14, a single heat exchanger 102, and a heat-mass exchanger 16. It is understood that in anti-frost mode, the LD regeneration circuit 12 will operate to dehumidify the regeneration airflow 26 and generate a dehumidified exhaust flow 38, so that moisture generated during evaporator coil defrosting can evaporate into the dehumidified exhaust flow 38.

[0077] As is evident from the foregoing, either of the regeneration systems 10 or 100 described in this article can operate in evaporator coil anti-frost mode.

[0078] In another aspect, a method of operating a regeneration system is provided. In some embodiments, the regeneration system is a regeneration system 10 according to any embodiment described herein. The method includes: heating a low-concentration liquid desiccant; flowing a first portion of the heated low-concentration liquid desiccant through a heat mass exchanger 16 to produce a high-concentration liquid desiccant 28; and using a second portion of the heated low-concentration liquid desiccant to remove moisture from the first portion of the low-concentration liquid desiccant within the heat mass exchanger 16.

[0079] In some embodiments, the temperature of the first portion is higher than the temperature of the second portion. In some embodiments, the heat mass exchanger 16 converts a low-concentration liquid desiccant into a high-concentration liquid desiccant.

[0080] In some embodiments, the second portion of the heated low-concentration liquid desiccant flows within an HMX heat transfer tube 34, which heats the first portion of the low-concentration liquid desiccant within a heat mass exchanger 16 (e.g., an HMX core 30).

[0081] In some embodiments, the second portion of the heated low-concentration liquid desiccant heats the regenerated air stream 26 that is in contact with the first portion of the low-concentration liquid desiccant. For example, in some embodiments, the regenerated air stream 26 may be heated within a regenerated air heater 46 (e.g., within the regenerated air heater 46).

[0082] In some embodiments, the regeneration system 10 includes a third portion of heated low-concentration liquid desiccant, wherein the third portion of heated low-concentration liquid desiccant heats the regeneration airflow 26 that is in contact with the first portion of the low-concentration liquid desiccant. In some such embodiments, a second portion of heated low-concentration liquid desiccant flows within an HMX heat transfer tube 34, which heats the first portion of the low-concentration liquid desiccant within a heat mass exchanger 16 (e.g., an HMX core 30).

[0083] In some such embodiments, the temperature of the second part is higher than the temperature of the third part.

[0084] Figure 13 A regeneration system 10 is shown according to some embodiments described herein, the regeneration system 10 operating using a regenerative heat and mass exchanger, an integrated shell and tube heat exchanger, a stratified tube, and a cold climate heat pump. Figure 14 A regeneration system 10 is shown according to some embodiments described herein, the regeneration system 10 operating using a regenerative heat and mass exchanger, an integrated shell and tube heat exchanger, and a cold climate heat pump. Figure 15 A regeneration system 10 according to some embodiments described herein is shown, the regeneration system 10 operating using refrigerant-air subcooling, a regenerative heat and mass exchanger, an integrated shell-and-tube heat exchanger, and a cold climate heat pump. Figure 13-15 In this system, the first heating zone 20 is used to deheat the refrigerant stream, the second heating zone 22 is used to condense the refrigerant stream, and the third heating zone 24 is used to subcool the refrigerant stream. A stratified liquid desiccant storage system (such as...) can be used. Figure 13-15 (as shown in the diagram) to retain the desiccant heated to different temperatures. In some embodiments, the regeneration system 10 may include layered tubes (such as...) Figure 13 and 15 (As shown). In Figure 13-15 In the embodiment shown, the condensate can be collected in a tank and used to regenerate the desiccant.

[0085] Specific embodiments

[0086] A first specific embodiment provides a regeneration system comprising:

[0087] A liquid desiccant regeneration circuit includes a liquid desiccant tank, a second heating zone, a first heating zone, and a heat and mass exchanger; and

[0088] A heating circuit includes a first heating zone and a second heating zone, wherein the temperature in the first heating zone is higher than the temperature in the second heating zone.

[0089] In this process, the low-concentration liquid desiccant in the liquid desiccant tank flows sequentially from the second heating zone to the first heating zone, then passes through the heat and mass exchanger, and is subsequently stored as a high-concentration liquid desiccant.

[0090] A portion of the low-concentration liquid desiccant leaving the first heating zone or the second heating zone is used as the heating fluid of the heat mass exchanger.

[0091] The second specific embodiment includes the first specific embodiment, wherein a low-concentration liquid desiccant leaving the first heating zone is fed into the heat mass exchanger and comes into contact with the regenerated air stream, and then leaves the heat mass exchanger as a high-concentration liquid desiccant.

[0092] The third specific embodiment includes the first or second specific embodiment, wherein a portion of the low-concentration liquid desiccant leaving the first or second heating zone flows within the HMX heat transfer tubes of the heat mass exchanger, and

[0093] The HMX heat transfer tube is adapted to heat the low-concentration liquid desiccant regenerated within the heat mass exchanger.

[0094] The fourth specific embodiment includes the second or third specific embodiment, wherein a portion of the low-concentration liquid desiccant leaving the second heating zone flows within the regeneration air heating tube to heat the regeneration air fed to the heat mass exchanger, and

[0095] In this process, the heated regenerated air flowing within the heat mass exchanger comes into contact with a low-concentration liquid desiccant within the heat mass exchanger and exits as exhaust gas.

[0096] The fifth specific embodiment includes the fourth specific embodiment, wherein a portion of the low-concentration liquid desiccant leaving the first heating zone flows within the HMX heat transfer tubes of the heat mass exchanger, and

[0097] The HMX heat transfer tube is adapted to heat the low-concentration liquid desiccant regenerated within the heat mass exchanger.

[0098] The sixth specific embodiment includes any one of the first to fifth specific embodiments, wherein the refrigerant circuit further includes an expansion valve and an evaporator, wherein the refrigerant leaves the second heating zone and then flows through the expansion valve and then through the evaporator;

[0099] The exhaust gas leaving the heat exchanger comes into contact with the refrigerant in the evaporator before being released from the regeneration system.

[0100] The seventh specific embodiment includes the sixth specific embodiment, wherein the refrigerant circuit further includes a compressor, wherein the refrigerant flows from the evaporator to the compressor before flowing through the first heating zone.

[0101] The eighth specific embodiment includes any one of the first to seventh specific embodiments, wherein the first heating zone and the second heating zone are part of the same heat exchanger.

[0102] The ninth specific embodiment includes any one of the first to eighth specific embodiments, wherein the first heating zone and the second heating zone are part of different heat exchangers.

[0103] The tenth specific embodiment includes any one of the first to ninth specific embodiments, and further includes a third heating zone;

[0104] The liquid desiccant regeneration circuit includes the third heating zone;

[0105] The heating circuit includes a third heating zone, wherein the temperature in the first heating zone is higher than the temperature in the second heating zone, and the temperature in the second heating zone is higher than the temperature in the third heating zone.

[0106] In this process, the low-concentration liquid desiccant in the liquid desiccant tank flows sequentially from the third heating zone to the second heating zone, then to the first heating zone, and then through the heat and mass exchanger, before returning to the liquid desiccant tank as a high-concentration liquid desiccant.

[0107] A portion of the low-concentration liquid desiccant leaving the second heating zone is used as the first heating fluid in the heat mass exchanger; and

[0108] A portion of the low-concentration liquid desiccant leaving the third heating zone is used as the second heating fluid of the heat mass exchanger.

[0109] The eleventh specific embodiment includes the tenth specific embodiment, wherein a low-concentration liquid desiccant leaving the first heating zone is fed into the heat mass exchanger and comes into contact with the regenerated air stream, and then leaves the heat mass exchanger as a high-concentration liquid desiccant.

[0110] The twelfth specific embodiment includes the eleventh specific embodiment, wherein the first heating fluid flows within the HMX heat transfer tube in the heat mass exchanger, and

[0111] The HMX heat transfer tube is adapted to heat the low-concentration liquid desiccant regenerated within the heat mass exchanger.

[0112] The thirteenth specific embodiment includes the eleventh or twelfth specific embodiment, wherein the second heating fluid flows within the regeneration air heating pipe to heat the regeneration air fed to the heat mass exchanger, and

[0113] In this process, the heated regenerated air flowing within the heat mass exchanger comes into contact with a low-concentration liquid desiccant within the heat mass exchanger and exits as exhaust gas.

[0114] The fourteenth specific embodiment includes any one of the tenth to thirteenth specific embodiments, wherein the refrigerant circuit further includes an expansion valve and an evaporator, wherein the refrigerant leaves the third heating zone and then flows through the expansion valve and then through the evaporator;

[0115] The exhaust gas leaving the heat exchanger comes into contact with the refrigerant in the evaporator before being released from the generation system.

[0116] The fifteenth specific embodiment includes any one of the first to fourteenth specific embodiments, wherein the regeneration system is adapted to operate in a heating mode, in which the low-concentration liquid desiccant does not flow through the heat mass exchanger, and further includes a liquid desiccant diversion loop.

[0117] In the heating mode, the low-concentration liquid desiccant in the liquid desiccant tank flows sequentially from the second heating zone to the first heating zone, then flows through the liquid desiccant diversion circuit, and then returns to the liquid desiccant tank.

[0118] The sixteenth specific embodiment relates to a regeneration system comprising:

[0119] A liquid desiccant regeneration circuit includes a liquid desiccant tank, a heating zone, and a heat and mass exchanger; and

[0120] The refrigerant circuit includes the heating zone, expansion valve, evaporator, and compressor;

[0121] In this embodiment, a first portion of the liquid desiccant in the liquid desiccant tank flows to the heat mass exchanger before returning to the liquid desiccant tank.

[0122] The regenerated air passes through the heat mass exchanger, where a first portion of the liquid desiccant flowing within the heat mass exchanger dehumidifies the regenerated air to form a dehumidified exhaust stream.

[0123] The dehumidified exhaust gas is fed into the evaporator to reduce frost on the evaporator coils.

[0124] The sixteenth specific embodiment can operate according to any one of the fifth to fifteenth specific embodiments.

[0125] The seventeenth specific embodiment relates to a method of operating a regeneration system, comprising:

[0126] Heating low-concentration liquid desiccant; and

[0127] A first portion of heated low-concentration liquid desiccant is flowed through a heat mass exchanger to produce a high-concentration liquid desiccant, wherein a second portion of the heated low-concentration liquid desiccant is used to remove moisture from the first portion of the low-concentration liquid desiccant within the heat mass exchanger.

[0128] The eighteenth specific embodiment includes the seventeenth specific embodiment, wherein the second portion of the heated low-concentration liquid desiccant flows within an HMX heat transfer tube, the HMX heat transfer tube heating the first portion of the low-concentration liquid desiccant within the heat mass exchanger.

[0129] The nineteenth specific embodiment includes the seventeenth or eighteenth specific embodiment, wherein the second portion of the heated low-concentration liquid desiccant heats the regenerated air stream in contact with the first portion of the low-concentration liquid desiccant.

[0130] The twentieth specific embodiment includes any one of the seventeenth to nineteenth specific embodiments, and further includes a third portion of heated low-concentration liquid desiccant.

[0131] The third portion of the heated low-concentration liquid desiccant heats the regenerated airflow that comes into contact with the first portion of the low-concentration liquid desiccant.

[0132] The various embodiments described above are provided by way of example only and should not be construed as limiting the appended claims. Those skilled in the art will readily recognize that various modifications and changes can be made without following the exemplary embodiments and applications illustrated and described herein, and without departing from the spirit and scope of the appended claims.

Claims

1. A regeneration system, comprising: A liquid desiccant regeneration circuit includes a liquid desiccant tank, a second heating zone, a first heating zone, and a heat and mass exchanger; as well as A heating circuit includes a first heating zone and a second heating zone, wherein the temperature in the first heating zone is higher than the temperature in the second heating zone. In this process, the low-concentration liquid desiccant in the liquid desiccant tank flows sequentially from the second heating zone to the first heating zone, then passes through the heat and mass exchanger, and is subsequently stored as a high-concentration liquid desiccant. A portion of the low-concentration liquid desiccant leaving the first heating zone or the second heating zone is used as the heating fluid of the heat mass exchanger.

2. The regeneration system according to claim 1, wherein, The low-concentration liquid desiccant leaving the first heating zone is fed into the heat mass exchanger and comes into contact with the regenerated air stream, and then leaves the heat mass exchanger as a high-concentration liquid desiccant.

3. The regeneration system according to claim 2, wherein, A portion of the low-concentration liquid desiccant leaving the first or second heating zone flows into the HMX heat transfer tubes in the heat mass exchanger, and The HMX heat transfer tube is adapted to heat the low-concentration liquid desiccant regenerated within the heat mass exchanger.

4. The regeneration system according to claim 2, wherein, A portion of the low-concentration liquid desiccant leaving the second heating zone flows into the regeneration air heating pipe to heat the regeneration air fed to the heat mass exchanger. In this process, the heated regenerated air flowing within the heat mass exchanger comes into contact with a low-concentration liquid desiccant within the heat mass exchanger and exits as exhaust gas.

5. The regeneration system according to claim 4, wherein, A portion of the low-concentration liquid desiccant leaving the first heating zone flows into the HMX heat transfer tubes in the heat mass exchanger, and The HMX heat transfer tube is adapted to heat the low-concentration liquid desiccant regenerated within the heat mass exchanger.

6. The regeneration system according to claim 1, wherein, The refrigerant circuit further includes an expansion valve and an evaporator, wherein the refrigerant leaves the second heating zone and then flows through the expansion valve and then through the evaporator; The exhaust gas leaving the heat exchanger comes into contact with the refrigerant in the evaporator before being released from the regeneration system.

7. The regeneration system according to claim 6, wherein, The refrigerant circuit further includes a compressor, wherein the refrigerant flows from the evaporator to the compressor before flowing through the first heating zone.

8. The regeneration system according to claim 1, wherein, The first heating zone and the second heating zone are part of the same heat exchanger.

9. The regeneration system according to claim 1, wherein, The first heating zone and the second heating zone are part of different heat exchangers.

10. The regeneration system according to claim 1, further comprising a third heating zone; in, The liquid desiccant regeneration circuit includes the third heating zone; The heating circuit includes a third heating zone, wherein the temperature in the first heating zone is higher than the temperature in the second heating zone, and the temperature in the second heating zone is higher than the temperature in the third heating zone. In this process, the low-concentration liquid desiccant in the liquid desiccant tank flows sequentially from the third heating zone to the second heating zone, then to the first heating zone, and then through the heat and mass exchanger, before returning to the liquid desiccant tank as a high-concentration liquid desiccant. A portion of the low-concentration liquid desiccant leaving the second heating zone is used as the first heating fluid in the heat mass exchanger; and A portion of the low-concentration liquid desiccant leaving the third heating zone is used as the second heating fluid of the heat mass exchanger.

11. The regeneration system according to claim 10, wherein, The low-concentration liquid desiccant leaving the first heating zone is fed into the heat mass exchanger and comes into contact with the regenerated air stream, and then leaves the heat mass exchanger as a high-concentration liquid desiccant.

12. The regeneration system according to claim 11, wherein, The first heating fluid flows within the HMX heat transfer tubes of the heat mass exchanger, and The HMX heat transfer tube is adapted to heat the low-concentration liquid desiccant regenerated within the heat mass exchanger.

13. The regeneration system according to claim 11, wherein, The second heating fluid flows within the regeneration air heating pipe to heat the regeneration air fed to the heat and mass exchanger. In this process, the heated regenerated air flowing within the heat mass exchanger comes into contact with a low-concentration liquid desiccant within the heat mass exchanger and exits as exhaust gas.

14. The regeneration system according to claim 10, wherein, The refrigerant circuit further includes an expansion valve and an evaporator, wherein the refrigerant leaves the third heating zone and then flows through the expansion valve and then through the evaporator; The exhaust gas leaving the heat exchanger comes into contact with the refrigerant in the evaporator before being released from the generation system.

15. The regeneration system according to claim 1, wherein, The regeneration system is adapted to operate in a heating mode, in which the low-concentration liquid desiccant does not flow through the heat and mass exchanger, and further includes a liquid desiccant diversion loop. In the heating mode, the low-concentration liquid desiccant in the liquid desiccant tank flows sequentially from the second heating zone to the first heating zone, then flows through the liquid desiccant diversion circuit, and then returns to the liquid desiccant tank.

16. A regeneration system, comprising: A liquid desiccant regeneration loop includes a liquid desiccant tank, a heating zone, and a heat and mass exchanger; as well as The refrigerant circuit includes the heating zone, expansion valve, evaporator, and compressor; In this embodiment, a first portion of the liquid desiccant in the liquid desiccant tank flows to the heat mass exchanger before returning to the liquid desiccant tank. The regenerated air passes through the heat mass exchanger, where a first portion of a liquid desiccant flowing within the heat mass exchanger dehumidifies the regenerated air to form a dehumidified exhaust stream. The dehumidified exhaust gas is fed into the evaporator to reduce the presence of frost on the evaporator coils.

17. A method of operating a regeneration system, comprising: Heating low-concentration liquid desiccant; as well as A first portion of heated low-concentration liquid desiccant is flowed through a heat mass exchanger to produce a high-concentration liquid desiccant, wherein a second portion of the heated low-concentration liquid desiccant is used to remove moisture from the first portion of the low-concentration liquid desiccant within the heat mass exchanger.

18. The method according to claim 17, wherein, The second portion of the heated low-concentration liquid desiccant flows within the HMX heat transfer tube, which heats the first portion of the low-concentration liquid desiccant within the heat mass exchanger.

19. The method of claim 17, wherein, The second portion of the heated low-concentration liquid desiccant heats the regenerated airflow that comes into contact with the first portion of the low-concentration liquid desiccant.

20. The method of claim 17, further comprising a third portion of heated, low-concentration liquid desiccant. in, The third portion of the heated low-concentration liquid desiccant heats the regenerated airflow that comes into contact with the first portion of the low-concentration liquid desiccant.

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