US20250067517A1

US20250067517A1 - Three-way heat exchange module having uniform fluid distribution

Info

Publication number: US20250067517A1
Application number: US18/482,454
Authority: US
Inventors: Saurabh PRABHAKAR; Ramesh Chandra BEHERA; Jason Warner; Douglas P. PELSOR
Original assignee: Copeland LP
Current assignee: Copeland LP
Priority date: 2023-08-21
Filing date: 2023-10-06
Publication date: 2025-02-27

Abstract

An HVAC system includes a refrigerant sub-system and an air treatment sub-system. The air treatment sub-system includes a three-way heat exchanger. The HVAC system is operable to circulate heat transfer fluid between the heat exchanger and the refrigerant sub-system. The heat exchanger includes panel assemblies, heat transfer fluid inlet and outlet manifolds, and a heat transfer fluid inlet and outlet. Each panel assembly includes a heat transfer fluid channel and a desiccant channel separated from the heat transfer fluid channel. The inlet and outlet manifolds are connected to the heat transfer fluid channel of each panel assembly, and each extend between lateral sides of the heat exchanger. The inlet manifold is closed at a first lateral side and connected to the inlet at a second lateral side, and the outlet manifold is closed at the second lateral side and connected to the outlet at the first lateral side.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to India patent application Ser. No. 202311055849, filed Aug. 21, 2023, the entire disclosure of which is incorporated by reference herein.

FIELD

The field relates generally to heating, ventilation, and air conditioning (HVAC) systems, and more particularly, to HVAC systems and methods including three-way heat exchange modules for transferring heat between a heat transfer fluid, a liquid desiccant, and air.

BACKGROUND

Heating, ventilation, and air conditioning (HVAC) systems are known for their heating, cooling, and moisture removal capabilities for treating outside air that is circulated through an indoor space. The vapor compression cycle is widely used in HVAC systems to regulate the temperature and humidity of the outside air. Typically, outside air is cooled below its dew point temperature to allow moisture in the air to condense on an evaporator coil, thus dehumidifying the air. Since this process often leaves the dehumidified air at an uncomfortably cold temperature, the air is then reheated to a temperature more comfortable to a user. The process of overcooling and reheating the air can become very energy-intensive and costly.
In some applications, HVAC systems include a vapor compression system used in combination with a liquid desiccant dehumidification system to remove moisture from the outside air without cooling it below its dew point temperature. For example, HVAC systems may include a refrigerant sub-system that operates under the vapor compression cycle and an air treatment sub-system that uses heat transfer fluid and liquid desiccant to simultaneously absorb heat (sensible cooling) and moisture (latent cooling) from warm outside air to produce cooled and dehumidified indoor air. The air treatment sub-system may include three-way heat transfer equipment that facilitates sensible and latent cooling of the warm outdoor air using the heat transfer fluid and the liquid desiccant.
In operation of a three-way heat exchanger, the liquid desiccant and heat transfer fluid are channeled through the heat exchanger and heat is transferred between the liquid desiccant and the heat transfer fluid. An outdoor air stream is directed through the heat exchanger, and heat transfer fluid absorbs heat from the air stream while the liquid desiccant absorbs moisture from the air stream. The liquid desiccant may circulate between the three-way heat exchanger and a regeneration system, in which diluted liquid desiccant rejects the absorbed moisture into a sacrificial fluid. The refrigerant sub-system interfaces with the air treatment sub-system, whereby refrigerant in an evaporation stage of the vapor compression cycle absorbs heat from the heat transfer fluid that has exited the three-way heat exchanger. The refrigerant is then channeled to a condensing stage in which the refrigerant rejects the absorbed heat into another fluid. Liquid desiccant treated by the regeneration system and heat transfer fluid treated by the refrigerant sub-system is then channeled back toward the three-way heat exchanger to again provide sensible and latent cooling of outside air.
This background section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.

SUMMARY

In one aspect, a heating, ventilation, and air conditioning (HVAC) system includes a refrigerant sub-system and at least one air treatment sub-system. The at least one air treatment sub-system includes a three-way heat exchanger for transferring heat between a heat transfer fluid, a liquid desiccant, and air. The HVAC system is operable to circulate the heat transfer fluid between the three-way heat exchanger and the refrigerant sub-system. The three-way heat exchanger defines mutually perpendicular lateral, longitudinal, and vertical directions, and the three-way heat exchanger includes panel assemblies, a heat transfer fluid inlet manifold and a heat transfer fluid outlet manifold, and a heat transfer fluid inlet and a heat transfer fluid outlet. The panel assemblies are arranged in succession in the lateral direction, and airflow gaps are defined between adjacent panel assemblies to allow the air to flow through the three-way heat exchanger. Each panel assembly includes a frame defining a heat transfer fluid channel and at least one vapor-permeable membrane disposed on a lateral face of the frame. At least one desiccant channel is defined between the at least one membrane and the frame, and the at least one desiccant channel is separated from the heat transfer fluid channel. The heat transfer fluid inlet and outlet manifolds are connected to the heat transfer fluid channel of each panel assembly, and the heat transfer fluid inlet and outlet manifolds each extend between first and second lateral sides of the three-way heat exchanger. The heat transfer fluid inlet manifold is closed at the first lateral side and the heat transfer fluid outlet manifold is closed at the second lateral side. The heat transfer fluid inlet is connected to the heat transfer fluid inlet manifold at the second lateral side and the heat transfer fluid outlet is connected to the heat transfer fluid outlet manifold at the first lateral side.
In another aspect, a heating, ventilation, and air conditioning (HVAC) system includes a refrigerant sub-system, a conditioner sub-system, and a regenerator sub-system. The conditioner sub-system includes a first three-way heat exchanger for transferring heat between a conditioner heat transfer fluid, a liquid desiccant, and a first air stream. The HVAC system is operable to circulate the conditioner heat transfer fluid between the first three-way heat exchanger and the refrigerant sub-system. The regenerator sub-system includes a second three-way heat exchanger for transferring heat between a regenerator heat transfer fluid, the liquid desiccant, and a second air stream. The HVAC system is operable to circulate the regenerator heat transfer fluid between the second three-way heat exchanger and the refrigerant sub-system. The first and second three-way heat exchangers each define mutually perpendicular lateral, longitudinal, and vertical directions, and each three-way heat exchanger includes panel assemblies, a heat transfer fluid inlet manifold and a heat transfer fluid outlet manifold, and a heat transfer fluid inlet and a heat transfer fluid outlet. The panel assemblies are arranged in succession in the lateral direction, and airflow gaps are defined between adjacent panel assemblies to allow the respective air stream to flow through the three-way heat exchanger. Each panel assembly includes a frame defining a heat transfer fluid channel and at least one vapor-permeable membrane disposed on a lateral face of the frame. At least one desiccant channel is defined between the at least one membrane and the frame, and the at least one desiccant channel is separated from the heat transfer fluid channel. The heat transfer fluid inlet and outlet manifolds are connected to the heat transfer fluid channel of each panel assembly, and the heat transfer fluid inlet and outlet manifolds each extend between first and second lateral sides of the three-way heat exchanger. The heat transfer fluid inlet manifold is closed at the first lateral side and the heat transfer fluid outlet manifold is closed at the second lateral side. The heat transfer fluid inlet is connected to the heat transfer fluid inlet manifold at the second lateral side and the heat transfer fluid outlet is connected to the heat transfer fluid outlet manifold at the first lateral side.
In another aspect, a three-way heat exchanger for use in an air treatment sub-system of a heating, ventilation, and air conditioning system, is operable to transfer heat between a heat transfer fluid, a liquid desiccant, and air. The three-way heat exchanger defines mutually perpendicular lateral, longitudinal, and vertical directions, and the three-way heat exchanger includes panel assemblies, a heat transfer fluid inlet manifold and a heat transfer fluid outlet manifold, and a heat transfer fluid inlet and a heat transfer fluid outlet. The panel assemblies are arranged in succession in the lateral direction, and airflow gaps are defined between adjacent panel assemblies to allow the air to flow through the three-way heat exchanger. Each panel assembly includes a frame defining a heat transfer fluid channel and at least one vapor-permeable membrane disposed on a lateral face of the frame. At least one desiccant channel is defined between the at least one membrane and the frame, and the at least one desiccant channel is separated from the heat transfer fluid channel. The heat transfer fluid inlet and outlet manifolds are connected to the heat transfer fluid channel of each panel assembly, and the heat transfer fluid inlet and outlet manifolds each extend between first and second lateral sides of the three-way heat exchanger. The heat transfer fluid inlet manifold is closed at the first lateral side and the heat transfer fluid outlet manifold is closed at the second lateral side. The heat transfer fluid inlet is connected to the heat transfer fluid inlet manifold at the second lateral side and the heat transfer fluid outlet is connected to the heat transfer fluid outlet manifold at the first lateral side.
Various refinements exist of the features noted in relation to the above-mentioned aspects. Further features may also be incorporated in the above-mentioned aspects as well. These refinements and additional features may exist individually or in any combination. For instance, various features discussed below in relation to any of the illustrated embodiments may be incorporated into any of the above-described aspects, alone or in any combination.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic flow diagram of a heating, ventilation, and air conditioning (HVAC) system.

FIG. 2 is a front perspective of a three-way heat exchanger included in the HVAC system of FIG. 1 .

FIG. 3 is a front perspective of the three-way heat exchanger, with various components omitted to show internal components.

FIG. 4 is a rear perspective of the three-way heat exchanger.

FIG. 5 is a rear perspective of the three-way heat exchanger with various components omitted, similar to FIG. 3 .

FIG. 6 is a left side elevation of the three-way heat exchanger with various components omitted, similar to FIGS. 3 and 5 .

FIG. 7 is a right side elevation of an example panel assembly included in the three-way heat exchanger of FIGS. 2-6 .

FIG. 8 is an exploded view of the panel assembly of FIG. 7 .

FIG. 9 is a schematic section of the panel assembly taken along section line 9-9 in FIG. 7 .

FIGS. 10A-10D are enlarged views of the sections A, B, C, D, respectively, shown in FIG. 8 .

FIG. 11 is a schematic showing flow of liquid desiccant and heat transfer fluid through the three-way heat exchanger of FIGS. 2-6 .

FIGS. 12-14 are schematics showing flow through the three-way heat exchanger similar to FIG. 11 , with various features and components to facilitate uniform flow distribution of the heat transfer fluid and/or the liquid desiccant.

Corresponding reference characters indicate corresponding parts throughout the drawings.

DETAILED DESCRIPTION

FIG. 1 is a schematic diagram of a heating, ventilation, and air conditioning (HVAC) system 100. The HVAC system 100 includes sub-systems 102-106 and a liquid desiccant circuit 108 which facilitate the heating, cooling, and moisture removal capabilities of the system 100. The sub-systems of the HVAC system 100 include a refrigerant sub-system 102, a conditioner sub-system 104, and a regenerator sub-system 106. The conditioner sub-system 104 and the regenerator sub-system 106 are usable to respectively treat first and second inlet air streams 110 and 114, and may be referred to herein as air treatment sub-systems 104 and 106. The HVAC system 100 may include additional components or other components than those shown and described with reference to FIG. 1 .
In an example operating mode of the HVAC system 100, the conditioner sub-system 104 removes heat from the first inlet air stream 110 and channels a conditioned outlet air stream 112 to a conditioned space (not shown), such as an interior of a building structure or vehicle. The conditioned outlet air stream 112 exiting the conditioner sub-system 104 may have a lower temperature than the first inlet air stream 110. Heat removed from the first inlet air stream 110 is transferred from the conditioning sub-system 104, to the refrigerant sub-system 102, and finally to the regenerator sub-system 106. The regenerator sub-system 106 transfers the heat into the second inlet air stream 114 and channels a heated outlet air stream 116 to the atmosphere.
The refrigerant sub-system 102 includes an evaporator 118, a condenser 120, a compressor 122, and an expansion valve 124. The compressor 122 may be any suitable compressor including, but not limited to, scroll, reciprocating, rotary, screw, and centrifugal compressors. The expansion valve 124 may be any suitable expansion valve, such as a thermal expansion valve. The expansion valve 124 may alternatively be any suitable expansion device, such as an orifice or capillary tube for example. The refrigerant sub-system 102 also includes a refrigerant loop 126 that circulates a working fluid, such as a refrigerant, between the evaporator 118, the compressor 122, the condenser 120, and the expansion valve 124. The refrigerant sub-system 102 may include additional components or other components than those shown and described with reference to FIG. 1 .
In operation of the refrigerant sub-system 102, the refrigerant in the loop 126 is channeled as a low pressure gas refrigerant 128 toward the compressor 122. The compressor 122 compresses the gas refrigerant 128, which raises the temperature and pressure of the refrigerant. Pressurized, high temperature gas refrigerant 130 exits the compressor 122 and is channeled toward the condenser 120, where the high pressure gas refrigerant 130 is condensed to a high pressure liquid refrigerant 132. The liquid refrigerant 132 exiting the condenser 120 is channeled toward the expansion valve 124 that reduces the pressure of the liquid. The reduced pressure fluid refrigerant 134, which may be a gas or a mixture of gas and liquid after passing through the expansion valve 124, is then channeled toward the evaporator 118. The fluid refrigerant 134 evaporates to a gas in the evaporator 118, exiting the evaporator as the low pressure gas refrigerant 128. The gas refrigerant 128 is then channeled back toward the compressor 122, where the gas refrigerant 128 is again compressed and the process repeats. Circulation of the refrigerant in the loop 126 may be driven by the compressor 122, and, more particularly, by a pressure differential that exists between the pressurized, high temperature gas refrigerant 130 exiting the compressor 122 and the low pressure gas refrigerant 128 entering the compressor 122. The direction of flow of the refrigerant through the loop 126, as shown in FIG. 1 , may be reversed to switch the heat transfer functions of the evaporator 118 and the condenser 120, and enable the HVAC system 100 to operate in various operating modes.
The conditioner sub-system 104 includes a first three-way heat exchanger 136 and a conditioner heat transfer fluid loop 138 that circulates a conditioner heat transfer fluid (e.g., water, a glycol-based fluid, or any combination thereof) to and from the first three-way heat exchanger 136. The conditioner sub-system 104 interfaces with the refrigerant sub-system 102 via the evaporator 118. In particular, the evaporator 118 is included in the refrigerant loop 126 and the conditioner heat transfer loop 138, and facilitates transfer of heat from the conditioner heat transfer fluid in the loop 138 into the fluid refrigerant 134 in the refrigerant loop 126. The conditioner sub-system 104 may include additional components or other components than those shown and described with reference to FIG. 1 . For example, the conditioner sub-system 104 may include one or more pumps (not shown) for circulating the conditioner heat transfer fluid in the loop 138 between the first three-way heat exchanger 136 and the evaporator 118. Suitable pumps that may be included in the conditioner sub-system 104 include, for example, centrifugal pumps, diaphragm pumps, positive displacement pumps, or any type of pump suitable for transferring liquid. The conditioner sub-system 104 may include additional heat transfer equipment that transfers heat from the conditioner heat transfer fluid into the atmosphere, or vice versa, depending on the operational requirements of the HVAC system 100 and other factors (e.g., a temperature and/or humidity of the first air inlet stream 110).
In operation of the conditioner sub-system 104, the conditioner heat transfer fluid in the loop 138 is channeled toward the evaporator 118. The conditioner heat transfer fluid is cooled in the evaporator 118 as heat is transferred from the conditioner heat transfer fluid into the fluid refrigerant 134 in the loop 126 to produce the gas refrigerant 128. Cooled conditioner heat transfer fluid 140 exiting the evaporator 118 is channeled toward and enters the first three-way heat exchanger 136. The first inlet air stream 110 is also directed through the first three-way heat exchanger 136. The first three-way heat exchanger 136 transfers heat from the first inlet air stream 110 into the conditioner heat transfer fluid 140, thus heating the conditioner heat transfer fluid. The heated conditioner heat transfer fluid 142 exiting the first three-way heat exchanger 136 is channeled back toward the evaporator 118 and the process repeats.
The regenerator sub-system 106 includes a second three-way heat exchanger 144 and a regenerator heat transfer fluid loop 146 that circulates a regenerator heat transfer fluid (e.g., water, a glycol-based fluid, or any combination thereof) to and from the second three-way heat exchanger 144. The regenerator sub-system 106 interfaces with the refrigerant sub-system 102 via the condenser 120. In particular, the condenser 120 is included in the refrigerant loop 126 and the regenerator heat transfer loop 146, and facilitates transfer of heat from the pressurized gas refrigerant 130 in the refrigerant loop 126 into the regenerator heat transfer fluid. The regenerator sub-system 106 may include additional components or other components than those shown and described with reference to FIG. 1 . For example, the regenerator sub-system 106 may include one or more pumps (not shown) for circulating the regenerator heat transfer fluid in the loop 146 between the three-way heat exchanger 144 and the condenser 120. Suitable pumps that may be included in the regenerator sub-system 106 include, for example, centrifugal pumps, diaphragm pumps, positive displacement pumps, or any type of pump suitable for transferring liquid. The regenerator sub-system 106 may include additional heat transfer equipment that transfers heat from the atmosphere into the regenerator heat transfer fluid, or vice versa, depending on the operational requirements of the HVAC system 100 and other factors (e.g., a temperature and/or humidity of the first air inlet stream 110).
In operation of the regenerator sub-system 106, the regenerator heat transfer fluid in the loop 146 is channeled toward the condenser 120. The regenerator heat transfer fluid is heated in the condenser as heat is transferred from the pressurized gas refrigerant 130 in the loop 126 into the regenerator heat transfer fluid to produce the liquid refrigerant 132. Heated regenerator heat transfer fluid 148 exiting the condenser is channeled toward and enters the second three-way heat exchanger 144. The second inlet air stream 114 is also directed through the second three-way heat exchanger 144. The second three-way heat exchanger 144 transfers heat from the regenerator heat transfer fluid into the second inlet air stream 114, thus cooling the regenerator heat transfer fluid. The heated outlet air stream 116 exiting the second three-way heat exchanger 144 has a greater temperature than the second inlet air stream 114. The cooled regenerator heat transfer fluid 150 exiting the three-way heat exchanger 144 is channeled back toward the condenser 120 and the process repeats.
The HVAC system 100 also includes the liquid desiccant circuit 108 that operates in conjunction with the sub-systems 102-106 to facilitate cooling the first inlet air stream 110 by latent and sensible cooling. Sensible cooling reduces the temperature of the conditioned outlet air stream 112 by removing heat from the first inlet air stream 110. Latent cooling reduces the temperature of the conditioned outlet air stream 112 by removing moisture from the first inlet air stream 110. The liquid desiccant circuit 108 includes a liquid desiccant that is channeled between the first and second three- way heat exchangers 136 and 144. Suitable liquid desiccants that may be used in the liquid desiccant circuit 108 include, for example, desiccant salt solutions, such as solutions of water and lithium chloride (LiCl), lithium bromide (LiBr), calcium chloride (CaCl₂), or any combination thereof, triethylene glycol, sodium hydroxide, sulfuric acid, and so-called ionic liquid desiccants, or organic salts that are liquid at room temperature and have organic cations and organic or inorganic anions.
The liquid desiccant circuit 108 may include one or more pumps (not shown) for channeling the liquid desiccant between the first three-way heat exchanger 136 and the second three-way heat exchanger 144. Suitable pumps that may be included in the liquid desiccant circuit 108 include, for example, centrifugal pumps, diaphragm pumps, positive displacement pumps, or any type of pump suitable for transferring liquid. The liquid desiccant circuit 108 may include one or more pumps for transferring the liquid desiccant from the second heat exchanger 144 toward the first heat exchanger 136 and one or more pumps for transferring the diluted liquid desiccant 154 from the first heat exchanger 136 toward the second heat exchanger 144
Concentrated liquid desiccant 152 in the liquid desiccant circuit 108 is channeled toward the first three-way heat exchanger 136 of the conditioner sub-system 104, where the concentrated liquid desiccant 152 removes moisture from the first inlet air stream 110. The concentrated liquid desiccant 152 cooperates with the cooled conditioner heat transfer fluid 140 in the first three-way heat exchanger 136 to absorb heat and moisture from the first inlet air stream 110. The conditioned outlet air stream 112 exiting the first three-way heat exchanger 136 may have a lower humidity and/or a lower temperature than the first inlet air stream 110. The liquid desiccant, having absorbed moisture from the first inlet air stream 110, exits the first three-way heat exchanger 136 as diluted liquid desiccant 154.
The diluted liquid desiccant 154 is channeled toward the second three-way heat exchanger 144 of the regenerator sub-system 106, where the diluted liquid desiccant 154 rejects moisture into the second inlet air stream 114. The diluted liquid desiccant 154 cooperates with the heated regenerator heat transfer fluid 148 in the second three-way heat exchanger 144 to reject heat and moisture into the second inlet air stream 114. The heated outlet air stream 116 exiting the second three-way heat exchanger 144 thus has a greater humidity as well as a higher temperature than the second inlet air stream 114. The liquid desiccant, having rejected moisture into the second inlet air stream 114, exits the regenerator sub-system 106 as concentrated liquid desiccant 152. The concentrated liquid desiccant 152 exiting the second three-way heat exchanger 144 is channeled back toward the first three-way heat exchanger 136, and the process repeats.
The liquid desiccant circuit 108 may also include a desiccant-desiccant heat exchanger 156 for transferring heat from the concentrated liquid desiccant 152 that has exited the second three-way heat exchanger 144 to the diluted liquid desiccant 154 that has exited the first three-way heat exchanger 136. The desiccant-desiccant heat exchanger 156 may facilitate improving the functions of the liquid desiccant in the three- way heat exchangers 136 and 144. For example, the desiccant-desiccant heat exchanger 156 may reduce a temperature of the concentrated liquid desiccant 152 to provide greater cooling and dehumidifying capabilities of the first three-way heat exchanger 136. Additionally and/or alternatively, the desiccant-desiccant heat exchanger 156 may increase a temperature of the diluted liquid desiccant 154 to enable the diluted liquid desiccant 154 to desorb a greater amount of moisture in the second three-way heat exchanger 144. The desiccant-desiccant heat exchanger 156 may be an inline heat exchanger or any suitable heat exchanger that facilitates direct heat transfer between the concentrated liquid desiccant 152 and the diluted liquid desiccant 154. The desiccant-desiccant heat exchanger 156 may alternatively facilitate indirect heat exchange between the concentrated liquid desiccant 152 and the diluted liquid desiccant 154, such as via a vapor compression heat pump. Auxiliary heating and cooling sources (e.g., heating and cooling fluid, such as water) may also be utilized, in addition to or in lieu of the heat exchanger 156, to respectively heat the diluted liquid desiccant 154 and cool the concentrated liquid desiccant 152. The liquid desiccant circuit 108 may include additional components or other components than those shown and described with reference to FIG. 1 .
Thus, in the example operating mode of the HVAC system 100, sensible cooling of the first inlet air stream 110 is facilitated by the first three-way heat exchanger 136 of the conditioner sub-system 104, which transfers heat from the inlet air stream 110 into the conditioner heat transfer fluid. The heat removed from the first inlet air stream 110 is then transferred sequentially between the sub-systems 104, 102, and 106 via the evaporator 118 and the condenser 120, and eventually is rejected into the second inlet air stream 114 via the second three-way heat exchanger 144. Latent cooling of the first inlet air stream 110 is also facilitated by the first three-way heat exchanger 136, which removes moisture from the inlet air stream 110 using the concentrated liquid desiccant 152. The moisture absorbed by the diluted liquid desiccant 154 is desorbed in the second three-way heat exchanger 144 into the second inlet air stream 114, which regenerates the concentrated liquid desiccant 152 that is then channeled back toward the first three-way heat exchanger 136.
The HVAC system 100 may operate in alternative operating modes than the example operating mode described above with reference to FIG. 1 . The example operating mode of the HVAC system 100 described above may be considered a warm weather operating mode of the HVAC system 100, in which warm, humid air in the first inlet air stream 110 is cooled and dehumidified using the conditioner sub-system 104 and the heat and moisture removed is transferred by the sub-systems 102 and 106 and the liquid desiccant circuit 108 and rejected into the second inlet air stream 114 to produce the heated, humidified outlet air stream 116 that is directed into the warm, humid ambient. In a cold weather operating mode of the HVAC system 100, the operation of the sub-systems 102-106 and the liquid desiccant circuit 108 may be reversed such that the first three-way heat exchanger 136 heats and humidifies cool, dry air in the first inlet air stream 110 to produce warm air with a comfortable humidity level in the outlet air stream 112 that is channeled to a conditioned space. In the cold weather operating mode, the direction of flow of the refrigerant in the loop 126 and the liquid desiccant in the liquid desiccant circuit 108 may be reversed, such that the air treatment sub-systems 104 and 106 switch their respective functions, or intake and outlet vents for the first and second inlet air streams 110 and 114 may be rearranged and/or reconfigured such that the direction of airflow directed through the first and second three- way heat exchangers 136 and 144 is reversed, with the outlet air stream 112 being channeled toward the ambient environment and the outlet air stream 116 being channeled toward the conditioned space. In still other operating modes of the HVAC system 100, depending on the operational requirements and desired setpoint temperature and humidity level within the conditioned space, one of the air treatment sub-system 104 and 106 may be idle or omitted from the HVAC system 100. For example, the air treatment sub-system 106 may be omitted and the refrigerant sub-system 104 may reject or absorb heat from a refrigerant-air heat exchanger 120, depending on the operating mode of the HVAC system 100. Where the regenerator sub-system 106 is omitted or idle, liquid desiccant in the liquid desiccant circuit 108 that is cycled through the first three-way heat exchanger 136 may be regenerated or diluted, depending on the operating mode of the HVAC system 100, using auxiliary regeneration equipment, dilution tanks, or the like.
Still with reference to FIG. 1 , the first three-way heat exchanger 136 and the second three-way heat exchanger 144 have substantially the same configuration. In alternative embodiments, the first three-way heat exchanger 136 and the second three-way heat exchanger 144 may have a different configuration. Although the conditioner sub-system 104 and the regenerator sub-system 106 are shown in FIG. 1 to include one three- way heat exchanger 136 and 144, respectively, any suitable number of three- way heat exchangers 136 and 144 may be included in the respective sub-system 104 and 106. The number of three-way heat exchangers 136 included in the conditioner sub-system 104 may be the same or different than the number of three-way heat exchangers 144 included in the regenerator sub-system 106. Where the conditioner sub-system 104 includes multiple three-way heat exchangers 136, the heat exchangers 136 may operate in series, in parallel, or any combination thereof. Where the regenerator sub-system 106 includes multiple three-way heat exchangers 144, the heat exchangers 144 may operate in series, in parallel, or any combination thereof.
Referring now to FIGS. 2-5 , an example three-way heat exchanger 200 for use in an air treatment sub-system of the HVAC system 100 of FIG. 1 will now be described. The three-way heat exchanger 200 may be implemented as a first three-way heat exchanger 136 in the conditioner sub-system 104 and/or as a second three-way heat exchanger 144 in the regenerator sub-system 106. FIG. 2 is a front perspective of the three-way heat exchanger 200. FIG. 3 is a front perspective of the three-way heat exchanger 200 with various components omitted to show internal components of the three-way heat exchanger 200. FIG. 4 is a rear perspective of the three-way heat exchanger 200. FIG. 5 is a rear perspective of the three-way heat exchanger 200 with various components omitted, similar to FIG. 3 .
The three-way heat exchanger 200 has a dimension in the X-axis, Y-axis and Z-axis, respectively. The X-axis, Y-axis and Z-axis are each mutually perpendicular. As described herein with respect to the three-way heat exchanger 200 and components of the heat exchanger 200 when assembled, dimensions in the Z-axis may be referred to as a “height,” dimensions in the Y-axis may be referred to as a “length,” and dimensions in the X-axis may be referred to as a “width.” The three-way heat exchanger 200 defines a lateral direction in the X-axis, a longitudinal direction in the Y-axis, and a vertical direction in the Z-axis. The X-axis may also be referred to herein as a lateral axis, the Y-axis may also be referred to herein as a longitudinal axis, and the Z-axis may also be referred to herein as a vertical axis. The three-way heat exchanger 200 has respectively opposite first and second lateral sides 202 and 204, first and second longitudinal sides 206 and 208, and first and second vertical sides 210 and 212. The first and second lateral sides 202 and 204 are spaced apart in the lateral direction, the first and second longitudinal sides 206 and 208 are spaced apart in the longitudinal direction, and the first and second vertical sides 210 and 212 are spaced apart in the vertical direction. Directional terms are used for solely for description of the three-way heat exchanger 200 and the spatial relation of the components of the heat exchanger. The examples shown and described are not limited to any particular orientation.
The three-way heat exchanger 200 includes a set of panel assemblies 214 arranged in succession in the lateral direction between the first lateral side 202 and the second lateral side 204. The individual panel assemblies 214 will be described in more detail below with reference to FIGS. 7-10 . Each panel assembly 214 is in the form of a plate structure that has an internal heat transfer fluid channel through which a heat transfer fluid, such as the conditioner heat transfer fluid in the loop 138 or regenerator heat transfer fluid in the loop 146, flows. Each panel assembly 214 also includes liquid desiccant channels on opposite sides of the heat transfer fluid channel. A liquid desiccant, such as the concentrated liquid desiccant 152 or the diluted liquid desiccant 154 in the liquid desiccant circuit 108, flows through the liquid desiccant channels. Liquid desiccant flowing through the liquid desiccant channels is separated from the heat transfer fluid flowing through the heat transfer fluid channel of the respective panel assembly, and heat is exchanged between the liquid desiccant in the liquid desiccant channels and the heat transfer fluid flowing through the heat transfer fluid channel. Airflow gaps 216, also referred to as air gaps 216, are defined between adjacent panel assemblies 214 in the lateral direction. Each airflow gap 216 extends primarily in the vertical and longitudinal directions.
Any suitable number of panel assemblies 214 may be included in the three-way heat exchanger 200. For example, the three-way heat exchanger 200 may include from 1 to 200 panel assemblies 214, from 1 to 100 panel assemblies 214, from 50 to 200 panel assemblies 214, from 50 to 100 panel assemblies 214, such as one panel assembly, ten panel assemblies 214, twenty panel assemblies 214, thirty panel assemblies 214, forty panel assemblies 214, fifty panel assemblies 214, sixty panel assemblies 214, seventy panel assemblies 214, eighty panel assemblies 214, ninety panel assemblies 214, 100 panel assemblies 214, or greater than 100 panel assemblies 214.
The panel assemblies 214 are supported on a base 240 at the second vertical side 212 of the three-way heat exchanger 200. The panel assemblies 214 extend substantially parallel to one another between the base 240 and the first vertical side 210 of the three-way heat exchanger 200. The panel assemblies 214 may, in operation of the three-way heat exchanger 200, deviate from a substantially parallel extent as fluid flows through the panel assemblies 214 and/or as air flows through the air gaps 216 between adjacent panel assemblies 214.
The three-way heat exchanger 200 includes end plates 218 and 220 at the first and second lateral sides 202 and 204, respectively. The end plates 218 may provide lateral support for the set of panel assemblies 214 and clamp the panel assemblies 214 together. The end plates 218 and 220 enclose an interior 222 of the three-way heat exchanger 200 at the first and second lateral sides 202 and 204. The end plates 218 and 220 are omitted from FIGS. 3 and 5 to show the arrangement of the panel assemblies 214, the airflow gaps 216 defined between adjacent panel assemblies 214, and the interior 222 of the three-way heat exchanger 200 in greater detail. The interior 222 of the three-way heat exchanger 200 may be enclosed at the first and second vertical sides 210 and 212 of the three-way heat exchanger by the set of panel assemblies 214. For example, adjacent panel assemblies 214 may be connected and/or in contact with one another at opposite vertical ends to seal the respective airflow gap 216 defined therebetween at the opposite vertical ends and to enclose the interior 222 of the three-way heat exchanger at the first and second vertical sides 210 and 212. Additionally and/or alternatively, the three-way heat exchanger 200 may include vertical end plates (not shown) to enclose the interior 222 at the first and second vertical sides 210 and 212.
The three-way heat exchanger 200 includes an airflow inlet 224 on the first longitudinal side 206 and an airflow outlet 226 on the second longitudinal side 208. The airflow inlet 224 and the airflow outlet 226 are respectively defined by longitudinal side panels 228 and 230 of the three-way heat exchanger 200. For example, the longitudinal side panels 228 and 230 may include openings in the form of grated or grille openings, shutters, louvers, dampers, or may have any other suitable open configuration to enable airflow to enter into and exit the three-way heat exchanger 200. In some examples, one or both of the longitudinal side panels 228 and 230 may include a filter to filter particulate and/or contaminants from an air stream that is treated by the three-way heat exchanger 200. The airflow inlet 224 and the airflow outlet 226 are in communication with the airflow gaps 216 defined between the adjacent panel assemblies 214, and allow an inlet air stream (e.g., the first or second inlet airstream 110 or 114 in FIG. 1 ) to flow through the three-way heat exchanger 200 in the longitudinal direction. The longitudinal side panels 228 and 230 are omitted from FIGS. 3 and 5 to show the arrangement of the panel assemblies 214, the airflow gaps 216 defined between adjacent panel assemblies 214, and the interior 222 of the three-way heat exchanger 200 in greater detail.
The three-way heat exchanger 200 also includes heat transfer fluid inlet 232 and outlet 234 and liquid desiccant inlet 236 and outlet 238. Heat transfer fluid (e.g., circulating in one of the heat transfer fluid loops 138 or 146 in FIG. 1 ) enters into and exits the three-way heat exchanger 200 via the heat transfer fluid inlet 232 and outlet 234, respectively. Liquid desiccant (e.g., circulating the liquid desiccant circuit 108 in FIG. 1 ) enters into and exits the three-way heat exchanger 200 via the liquid desiccant inlet 236 and outlet 238, respectively.
As shown in FIG. 4 , the heat transfer fluid inlet 232 and outlet 234 and the liquid desiccant inlet 236 and outlet 238 are each located on the same longitudinal side (e.g., the second longitudinal side 208) of the three-way heat exchanger 200. This may simplify installation of the three-way heat exchanger 200 and/or reduce bulk of the heat exchanger 200 in an air treatment sub-system when installed. Locating the heat transfer fluid inlet 232 and outlet 234 and the liquid desiccant inlet 236 and outlet 238 on the second longitudinal side 208 may further simplify installation and/or reduce bulk of the three-way heat exchanger 200 because the second longitudinal side 208 may suitably be oriented toward the other components of the air treatment sub-system when installed. The second longitudinal side 208 includes the airflow outlet 226, which is oriented opposite the external environment toward which the airflow inlet 224 is oriented. Thus, the second longitudinal side 208 may be oriented toward and/or connected to ductwork and other components of the air treatment sub-system, so that when installed, may suitably be located opposite the first longitudinal side 206 and the airflow inlet 224 of the three-way heat exchanger 200.
Additionally, as shown in FIG. 4 , the heat transfer fluid inlet 232 and outlet 234 are located on opposite lateral and vertical sides of the three-way heat exchanger 200. The liquid desiccant inlet 236 and outlet 238 are also located on opposite lateral and vertical sides of the three-way heat exchanger 200. In the illustrated example, the heat transfer fluid inlet 232 and the liquid desiccant outlet 238 are both located proximate the second vertical side 212 and the second lateral side 204, and the heat transfer fluid outlet 234 and the liquid desiccant inlet 236 are both located proximate the first vertical side 210 and the first lateral side 202. The respective locations of the heat transfer fluid inlet 232 and outlet 234 and/or the respective locations of the liquid desiccant inlet 236 and outlet 238 may be swapped in some examples. For example, the heat transfer fluid inlet 232 and the liquid desiccant inlet 236 may both be located proximate the second vertical side 212 and the second lateral side 204, and the heat transfer fluid outlet 234 and the liquid desiccant outlet 238 may both be located proximate the first vertical side 210 and the first lateral side 202. Alternatively, the heat transfer fluid inlet 232 and the liquid desiccant inlet 236 may both be located proximate the first vertical side 210 and the first lateral side 202, and the heat transfer fluid outlet 234 and the liquid desiccant outlet 238 may both be located proximate the second vertical side 212 and the second lateral side 204. Alternatively, the heat transfer fluid inlet 232 and the liquid desiccant outlet 238 may both be located proximate the first vertical side 210 and the first lateral side 202, and the heat transfer fluid outlet 234 and the liquid desiccant inlet 236 may both be located proximate the second vertical side 212 and the second lateral side 204. The locations of the heat transfer fluid inlet 232 and outlet 234 and the liquid desiccant inlet 236 and outlet 238 may vary depending on a desired flow direction of the heat transfer fluid and the liquid desiccant through the panel assemblies 214. The liquid desiccant inlet 236 and the heat transfer fluid outlet 234 may be defined by (e.g., made integral with) the end plate 218 and the liquid desiccant outlet 238 and the heat transfer fluid inlet 232 may be defined by (e.g., made integral with) the end plate 220. Alternatively, the heat transfer fluid inlet 232 and outlet 234 and the liquid desiccant inlet 236 and outlet 238 may each be defined by a conduit (e.g., a pipe, tube, hose, or other suitable fluid conduit) that extends longitudinally through an opening in the respective end plate 218 and 220.
Referring to FIGS. 7-9 , an example panel assembly 300 suitable for use as the individual panel assemblies 214 will now be described. In the example three-way heat exchanger 200, all the panel assemblies 214 have substantially the same configuration as the panel assembly 300 shown in FIGS. 7-9 . Some of or all the panel assemblies 214 may include additional components, fewer components, or other components than the panel assembly 300. FIG. 7 is a right side elevation of the example panel assembly 300. FIG. 8 is an exploded view of the panel assembly 300. FIG. 9 is a schematic section of the panel assembly 300 taken along section line 9-9 in FIG. 7 . The spatial relation of components of the panel assembly 300 will be described with respect to the X-axis, Y-axis, and Z-axis, and the lateral direction, longitudinal direction, and vertical direction defined by the three-way heat exchanger 200. The panel assembly 300 will also be described in the orientation when implemented and installed in the three-way heat exchanger 200. Directional terms are used to describe components of the panel assembly 300 solely for convenience of description. The examples shown and described are not limited to any particular orientation.
The panel assembly 300 includes a frame 302 that defines first and second vertical ends 304 and 306, in the Z-axis, first and second lateral faces 305 and 307, in the X-axis, and first and second longitudinal ends 308 and 310, in the Y-axis, of the panel assembly 300. The frame 302 includes opposite first and second header sections 312 and 314 respectively located at the first and second vertical ends 304 and 306. The frame 302 also includes a middle section 316 between the opposite header sections 312 and 314. The header sections 312 and 314 respectively define liquid desiccant header areas 320 and 322. The middle section 316 defines a heat transfer fluid area 324. The liquid desiccant header areas 320 and 322 are separated from the heat transfer fluid area 324 by portions of the frame 302 that respectively extend between the heat transfer fluid area 324 and one of the liquid desiccant header areas 320 and 322.
The panel assembly 300 also includes first and second plates 326 and 328 disposed on opposite lateral faces of the frame 302, covering the middle section 316 of the frame 302. The first and second plates 326 and 328 may be attached to the frame 302 or may be made integral with the frame 302. Suitable techniques for attaching the plates 326 and 328 to the frame 302 may include, for example, welding (e.g., laser, induction, or radio-frequency welding), adhesive bonding, thermal bonding, or another suitable technique for joining materials together. The frame 302 and the plates 326 and 328 may be made from dissimilar but compatible materials for welding together. For example, the plates 326 and 328 may be made from a polymer material that is compatible for welding to the frame 302. The material used for the plates 326 and 328 may also be selected based on its compatibility with the liquid desiccant used in the three-way heat exchanger 200. Suitable polymer materials for the plates 326 and 328 include, for example, polyolefins (e.g., polypropylene and/or polyethylene), acrylonitrile butadiene styrene (ABS), and combinations thereof. The plates 326 and 328 may include additives that improve properties such as laser-absorbing and conductivity properties, as well as the strength and/or stiffness of the plates 326 and 328. In other examples, the frame 302 and the plates 326 and 328 may be made from any other suitable materials that enable the three-way heat exchanger 200 to function as described.
The plates 326 and 328 envelop and seal the heat transfer fluid area 324 of the frame, defining a heat transfer fluid channel 330 of the panel assembly 300 between the plates 326 and 328 (see FIG. 9 ). As described below, in operation of the three-way heat exchanger 200, heat transfer fluid flows between the plates 326 and 328 through the heat transfer fluid channel 330 and liquid desiccant flows over an outer surface of the plates 326 and 328, opposite the heat transfer fluid channel 330. The plates 326 and 328 isolate the liquid desiccant from the heat transfer fluid in the channel 330, and allow heat to transfer between the liquid desiccant and the heat transfer fluid. The plates 326 and 328 may extend over one or both of liquid desiccant header areas 320 and 322 and define openings (e.g., apertures 360) that align with the one or both of the liquid desiccant header areas 320 and 322 to enable liquid desiccant to flow therethrough. In the example panel assembly 300, each of the plates 326 and 328 includes a series of apertures 360 located adjacent the liquid desiccant header 320 and a series of apertures 362 located adjacent the liquid desiccant header area 322. Liquid desiccant may flow through the apertures 360 and 362 of each plate 326 and 328 to enter and/or exit the liquid desiccant header area 320 and 322, respectively.
A netting or mesh (not shown) may be disposed in the heat transfer fluid channel 330 to maintain a width of the heat transfer fluid channel under negative pressure. The netting or mesh may also facilitate more constant flow rates of the heat transfer fluid through the channel 330. The netting or mesh may also facilitate improving flow distribution of the heat transfer fluid between the panel assemblies 300 in the three-way heat exchanger 200. The netting or mesh may also provide turbulation of the heat transfer fluid to increase heat transfer with the liquid desiccant flowing over the outer surfaces of the plates 326 and 328. A wide variety of materials may be used for the netting or mesh. For example, the netting or mesh may include the same polymer material as the plates (e.g., polyolefins, ABS, or combinations thereof).
The panel assembly 300 also includes membranes 332 and 334 disposed on the opposite lateral faces 305 and 307 of the frame 302. In other examples, only one of the membranes 332 or 334 may be included in the panel assembly 300. The membranes 332 and 334 cover the outer surfaces of the plates 326 and 328. As shown in FIG. 9 , liquid desiccant channels 336 and 338 are respectively defined between the membrane 332 and the plate 326 and the membrane 334 and the plate 328. The membranes 332 and 334 also envelop and seal the liquid desiccant header areas 320 and 322. Each liquid desiccant channel 336 and 338 connects the liquid desiccant header areas 320 and 322 in fluid communication. As described below, in operation of the three-way heat exchanger 200, liquid desiccant flows through one of the liquid desiccant header areas 320 or 322, into the liquid desiccant channels 336 and 338, over the outer surfaces of the plates 326 and 328 and behind the membranes 332 and 334, and finally into the other one of the liquid desiccant header areas 320 or 322. The plates 326 and 328 limit contact between the liquid desiccant flowing in the liquid desiccant channels 336 and 338 and heat transfer fluid flowing through the heat transfer fluid channel 330, and enable heat to transfer therebetween. In examples where only one of the membranes 332 or 334 is included in the panel assembly 300, only one liquid desiccant channel 336 or 338 may be defined between the membrane 332 or 334 and the plate 326 or 328. In these examples, the plate 326 or 328 on the lateral face 305 or 307 opposite the liquid desiccant channel 336 or 338 may envelop and seal the liquid desiccant header areas 320 and 322 and restrict flow of liquid desiccant opposite the liquid desiccant channel 336 or 338.
The membranes 332 and 334 are attached to one of the lateral faces 305 and 307, respectively, of the frame 302 to envelop and seal the liquid desiccant header areas 320 and 322. The membranes 332 and 334 may also be attached to the outer surface of the respective plate 326 and 328, which may facilitate maintaining a width of the liquid desiccant channels 336 and 338 and/or limiting a propensity of the membranes 332 and 334 to bulge outward when liquid desiccant flows through the liquid desiccant channels 336 and 338. The membranes 332 and 334 may be attached to the lateral faces 305 and 307 of the frame 302 and/or the outer surfaces of the plates 326 and 328 using any suitable technique, such as adhesive bonding or heat sealing (e.g., welding), for example. The membranes 332 and 334 may be respectively attached to the plates 326 and 328 directly by heat sealing (e.g., welding) where compatible materials (e.g., polyolefins) are used for the membranes 332 and 334 and the respective plates 326 and 328. An outer bonding layer (not shown) may be applied over the outer surfaces of the plates 326 and 328 to improve the quality or ease of forming the heat seals (e.g., welds) with the respective membranes 332 and 334. The outer surfaces of the plates 326 and 328 may include raised patterns or dot features (not shown) to which the membranes 332 and 334 are adhered, heat sealed, or otherwise attached. The raised patterns may be formed on the frame 302 and/or plates 326 and 328 by thermoforming, embossing, or other suitable techniques. Attaching the membranes 332 and 334 to the dot features or raised patterns may provide an additional advantage of facilitating uniform distribution of the liquid desiccant across the liquid desiccant channels 336 and 338 in the longitudinal direction and reducing stresses that can lead to warping of the plates 326 and 328. Warping of the plates 326 and 328 may degrade the ability to transfer heat and moisture between the heat transfer fluid, the liquid desiccant, and air that flows across the membranes 332 and 334 in operation of the three-way heat exchanger 200. Additional detail on attaching the membranes 332 and 334 to the frame 302 and the respective plates 326 and 328 is described in U.S. Pat. No. 11,022,330, issued on Jun. 1, 2021, and U.S. Pat. No. 10,921,001, issued on Feb. 16, 2021, the disclosures of each of which are hereby incorporated herein by reference in their entirety.
The membranes 332 and 334 are made of a vapor-permeable material that permits transfer of water vapor therethrough to enable liquid desiccant flowing in the liquid desiccant channels 336 and 338 to absorb moisture from and desorb moisture into air flowing across the membranes 332 and 334. In some examples, the membranes 332 and 334 may each be made from a polypropylene material or other suitable vapor-permeable polymeric material. The vapor-permeable material used for the membranes 332 and 334 may be microporous (e.g., having a pore size less than 0.5 micrometers (μm)). Examples of suitable microporous membranes are disclosed in U.S. Pat. No. 9,101,874, issued on Aug. 11, 2015, the disclosure of which is hereby incorporated by reference herein in its entirety. By way of example, suitable commercially available membrane include the EZ2090 polypropylene, microporous membrane from Celgard. Microporous membranes 332 and 334 may have 40-80% open area, pore sizes of less than 0.5 μm, and a thickness of less than 100 μm. Some example microporous membranes may have greater than 80% open area. One suitable membrane is approximately 65% open area and has a thickness of approximate 20 μm. This type of membrane is structurally very uniform in pore size and is thin enough to not create a significant thermal barrier. Other possible membranes include membranes from 3M, Lydall, and other manufacturers. The membranes 332 and 334 may include any suitable vapor-permeable material that permits water transfer therethrough to enable the liquid desiccant in the liquid desiccant channels 336 and 338 to absorb moisture from or desorb moisture into air flowing over the membranes 332 and 334.
The frame 302 defines a liquid desiccant inlet port 340 that feeds liquid desiccant into the liquid desiccant header area 320 and a liquid desiccant outlet port 342 that receives liquid desiccant from the liquid desiccant header area 322. The liquid desiccant inlet port 340 is defined by the first header section 312, and is located adjacent to the liquid desiccant header area 320 at the first vertical end 304 and the second longitudinal end 310 of the panel assembly 300. The liquid desiccant outlet port 342 is defined by the second header section 314, and is located adjacent to the liquid desiccant header area 322 at the second vertical end 306 and the first longitudinal end 308 of the panel assembly 300. Thus, the liquid desiccant inlet and outlet ports 340 and 342 are located on opposite longitudinal and vertical ends of the panel assembly 300.
As represented by the flow lines 344 in FIGS. 7 and 9 , in operation of the three-way heat exchanger 200, liquid desiccant is supplied into the liquid desiccant header area 320 of the panel assembly 300 via the liquid desiccant inlet port 340, flows through each of the liquid desiccant channels 336 and 338 and into the liquid desiccant header area 322, and exits the panel assembly 300 via the liquid desiccant outlet port 342. In the illustrated example, the flow direction of the liquid desiccant is vertically downward. The liquid desiccant may have alternative flow directions. For example, the liquid desiccant may flow vertically upward through the liquid desiccant channels 336 and 338, being supplied into the liquid desiccant header area 322 and exiting via the liquid desiccant header area 320. In other examples, the orientation of the panel 300 in the three-way heat exchanger 200 may be such that the liquid desiccant flows in a substantially horizontal flow direction. In yet other examples, the panel 300 may be oriented at an oblique angle in the three-way heat exchanger 200 such that the liquid desiccant flows in both a vertical and horizontal direction.
The frame 302 also defines a heat transfer fluid inlet port 346 that feeds heat transfer fluid into the heat transfer fluid channel 330 and a heat transfer fluid outlet port 348 that receives heat transfer fluid from the heat transfer fluid channel 330. The heat transfer fluid inlet and outlet ports 346 and 348 are defined by the middle section 316 and are located on opposite vertical ends of the heat transfer fluid channel 330. The heat transfer fluid inlet port 346 is located proximate to the second vertical end 306 of the panel assembly 300, and the heat transfer fluid outlet port 348 is located proximate to first vertical end 304 of the panel assembly 300. The heat transfer fluid inlet and outlet ports 346 and 348 are also located on opposite longitudinal ends of the heat transfer fluid channel 330, the heat transfer fluid inlet port 346 being located at the second longitudinal end 310 and the heat transfer fluid outlet port 348 being located at the first longitudinal end 308 of the panel assembly 300.
As represented by the flow lines 350 in FIGS. 7 and 9 , in operation of the three-way heat exchanger 200, heat transfer fluid is supplied into the heat transfer fluid channel 330 of the panel assembly 300 via the heat transfer fluid inlet port 346, flows therethrough, and exits the panel assembly 300 via the heat transfer fluid outlet port 348. In the illustrated example, the flow direction of the heat transfer fluid is vertically upward. The heat transfer fluid may have alternative flow directions. For example, the heat transfer fluid may flow vertically downward through the heat transfer fluid channel 330. In other examples, the orientation of the panel 300 in the three-way heat exchanger 200 may be such that the heat transfer fluid flows in a substantially horizontal flow direction. In yet other examples, the panel 300 may be oriented at an oblique angle in the three-way heat exchanger 200 such that the heat transfer fluid flows in both a vertical and horizontal direction. In the illustrated example, the heat transfer fluid and the liquid desiccant flow in counter-flow relation to one another through the panel assembly 300. In other examples, the heat transfer fluid and the liquid desiccant may flow in the same flow direction through the panel assembly 300.
FIGS. 10A-10D are enlarged views of the sections A, B, C, D, respectively, of the frame 302 shown in FIG. 8 , and depict microchannels or apertures that provide fluid connection between the ports 340, 342, 346, and 348 and the respective fluid areas defined in the panel assembly 300. As shown in FIGS. 10A and 10B, the heat transfer fluid inlet port 346 is connected to the heat transfer fluid area 324 by apertures 352 (FIG. 10B) and the heat transfer fluid outlet port 348 is connected to the heat transfer fluid area 324 by apertures 354 (FIG. 10A). The heat transfer fluid area 324 defines the heat transfer fluid channel 330 when sealed on the opposite lateral faces 305 and 307 of the frame 302 by the plates 326 and 328. As indicated by the flow lines 350 in FIGS. 10A and 10B, heat transfer fluid enters the heat transfer fluid channel 330 from the inlet port 346 via the apertures 352 and exits the channel 330 into the outlet port 348 via the apertures 354.
As shown in FIGS. 10C and 10D, the liquid desiccant inlet port 340 is connected to the first liquid desiccant header area 320 by apertures 356 (FIG. 10C) and the liquid desiccant outlet port 342 is connected to the second liquid desiccant header area 322 by apertures 358 (FIG. 10D). As indicated by the flow lines 344 in FIGS. 10C and 10D, liquid desiccant enters the first liquid desiccant header area 320 from the inlet port 340 via the apertures 356, flows into and through the liquid desiccant channels 336 and 338 (FIG. 9 ), into the second liquid desiccant header area 322, and exits the header area 322 into the outlet port 342 via the apertures 358. In the illustrated example of FIGS. 10A-10D, each of the apertures 352-358 include two apertures. Any suitable number of apertures may be used for the apertures 352-358. In some examples, a greater number of apertures may be used for some of the apertures 352-358 than the other apertures 352-358. The number, size, and/or shape of the apertures 352-358 may be the same or different. The number of apertures, as well as the size and shape, used for each of the apertures 352-358 may also vary between panel assemblies 300.
Referring again to FIGS. 3 and 5 , and with additional reference to FIG. 6 which shows a left elevation of the three-way heat exchanger 200 with various components omitted similar to FIGS. 3 and 5 , multiple panel assemblies 214 are arranged in succession in the lateral direction as described above. The panel assemblies 214 may each be a panel assembly 300, and will be referred to as the panel assemblies 300 hereinafter for convenience of description. In FIGS. 3, 5, and 6 , the plates 326 and 328 and the membranes 332 and 334 are omitted for convenience of illustration.
When assembled and installed in the three-way heat exchanger 200, for each pair of adjacent panel assemblies 300, the membrane 332 of one of the panel assemblies 300 faces the membrane 334 of the other one of the panel assemblies 300. The airflow gaps 216 are defined between the adjacent membranes 332 and 334. Each panel assembly 300 has a reduced width over the middle section 316. Adjacent panel assemblies 300 may be connected via their adjacent header sections 312 and 314 and spaced apart over their adjacent middle sections 316 to define the airflow gaps 216. The header sections 312 and 314 of adjacent panel assemblies may be connected by any suitable means, such as fasteners. The header sections 312 and 314 may include sealing members (e.g., O-rings or elastomeric seals) that create a fluid-tight seal between the header sections 312 and 314 of adjacent panel assemblies 300 when connected. As such, the header sections 312 and 314 of the panel assemblies 300 may enclose the three-way heat exchanger 200 at the first and second vertical ends 210 and 212, and the middle sections 316 defining the airflow gaps 216 allow for air to flow in the longitudinal direction between the airflow inlet 224 and the airflow outlet 226. Each panel assembly 300 may include standoffs or spacers (not labeled) extending in the lateral direction outward from the middle section 316 along the opposite longitudinal ends 308 and 310. The standoffs or spacers may maintain the spacing between the middle sections 316 of adjacent panel assemblies 300 and thus maintain the width of the airflow gaps 216 defined therebetween.
The panel assemblies 300 are arranged in the three-way heat exchanger 200 such that, for each panel assembly, the first and second lateral faces 305 and 307 of the frame 302 are respectively oriented toward the first and second lateral sides 202 and 204 of the three-way heat exchanger 200. The first and second longitudinal ends 308 and 310 are respectively located at the first and second longitudinal sides 206 and 208 of the three-way heat exchanger 200, and the first and second vertical ends 304 and 306 are respectively located at the first and second vertical sides 210 and 212 of the three-way heat exchanger 200.
The ports 340, 342, 346, and 348 of the panel assemblies 300 align to define respective manifolds of the three-way heat exchanger 200 extending in the lateral direction through which heat transfer fluid and liquid desiccant flow to and from the panel assemblies 300 between the first and second lateral sides 202 and 204. The liquid desiccant inlet ports 340 of the panel assemblies 300 align to form a liquid desiccant inlet manifold 242 that extends between the first and second lateral sides 202 and 204 proximate to the first vertical side 210 and the second longitudinal side 208 of the three-way heat exchanger 200. The liquid desiccant outlet ports 342 of the panel assemblies 300 align to form a liquid desiccant outlet manifold 244 that extends between the first and second lateral sides 202 and 204 proximate to the second vertical side 212 and the first longitudinal side 206 of the three-way heat exchanger 200. The heat transfer fluid inlet ports 346 of the panel assemblies 300 align to form a heat transfer fluid inlet manifold 246 that extends between the first and second lateral sides 202 and 204 proximate to the second vertical side 212 and the second longitudinal side 208 of the three-way heat exchanger 200. The heat transfer fluid outlet ports 348 of the panel assemblies 300 align to form a heat transfer fluid outlet manifold 248 that extends between the first and second lateral sides 202 and 204 proximate to the first vertical side 210 and the first longitudinal side 206 of the three-way heat exchanger 200. The panel assemblies 300 may include O-rings or other elastomeric sealing members that form liquid-tight seals between the aligning ports 340, 342, 346, and 348 of the adjacent panel assemblies to prevent fluid from leaking out of the respective manifolds 242-248.
As shown in FIGS. 3 and 5 , conduits 250, 252, 254, and 256 are used to fluidly connect the heat transfer fluid inlet 232 and outlet 234 and the liquid desiccant inlet 236 and outlet 238 to a respective manifold for heat transfer fluid and liquid desiccant entering and exiting the three-way heat exchanger 200. The liquid desiccant inlet 236 is fluidly connected to the liquid desiccant inlet manifold 242 by the conduit 250. The liquid desiccant outlet 238 is fluidly connected to the liquid desiccant outlet manifold 244 by the conduit 252. The heat transfer fluid inlet 232 is fluidly connected to the heat transfer fluid inlet manifold 246 by the conduit 254. The heat transfer fluid outlet 234 is fluidly connected to the heat transfer fluid outlet manifold 248 by the conduit 256. The conduits 250-256 may include any suitable fluid conduit (rigid and/or flexible) that enables heat transfer fluid and liquid desiccant to flow between the respective inlet and outlet and manifold, including, for example and without limitation, pipes, hoses, tubes, and combinations thereof. Each conduit 250-256 may be attached to the respective manifold 242-248 by coupling an end of the conduit to an end panel assembly 300 (i.e., the panel assembly 300 immediately adjacent to the lateral side 202 or 204) at the appropriate one of the ports 340, 342, 346, and 348. The conduits 250-256 may be attached to the appropriate port 340, 342, 346, and 348 of an end panel assembly 300 using any suitable means, include fasteners, threads, clamps, and the like.
As described above, the heat transfer fluid inlet 232 and outlet 234 and the liquid desiccant inlet 236 and outlet 238 are each located on the longitudinal side 208 of the three-way heat exchanger 200. The conduits 250-256 extend longitudinally at an approximately 90° angle relative to the lateral extent of the respective manifold 242-248 to which the conduits are connected. The conduits 250-256 each have a suitable longitudinal extent that depends on the longitudinal location of the respective manifold 242-248 relative to the longitudinal side 208 of the heat exchanger 200. The conduits 250 and 254 have a shorter longitudinal extent than the conduits 252 and 256 because the manifolds 242 and 246 extend proximate to the second longitudinal side 208 and the manifolds 244 and 248 extend proximate to the first longitudinal side 206. The conduits 250-256 also extend at substantially the vertical height of the respective manifold 242-248 to minimize the extent of the conduit and reduce bulk of the heat exchanger 200. As such, the conduits 250 and 252 extend on opposite vertical sides and the conduits 254 and 256 extend on opposite vertical sides of the heat exchanger 200. Additionally, the conduits 250 and 252 extend on opposite lateral sides because the liquid desiccant inlet 236 and outlet 238 are located on opposite lateral sides of the heat exchanger 200, and the conduits 254 and 256 extend on opposite lateral sides because the heat transfer fluid inlet 232 and outlet 234 are located on opposite lateral sides of the heat exchanger 200.
Each of the manifolds 242-248 is closed at the lateral side 202 or 204 of the heat exchanger 200 opposite of the inlet or outlet to which the manifold is connected. As such, the liquid desiccant inlet manifold 242 is closed at the second lateral side 204, the liquid desiccant outlet manifold 244 is closed at the first lateral side 202 opposite the liquid desiccant inlet manifold 242, the heat transfer fluid inlet manifold 246 is closed at the first lateral side 202, and the heat transfer fluid outlet manifold 248 is closed at the second lateral side 204 opposite the heat transfer fluid inlet manifold 246. The manifolds 242-248 may be closed at the respective lateral sides 202 or 204 by the end plate 218 or 220 (shown in FIGS. 2 and 4 ). In particular, the end plate 218 may plug the ports 342 and 346 of the panel assembly 300 at the end of the panel assemblies 300 that is adjacent to the first lateral side 202 to close the manifolds 244 and 246 at the first lateral side 202. The end plate 220 may plug the ports 340 and 348 of the panel assembly 300 at the end of the panel assemblies 300 that is adjacent to the second lateral side 204 to close the manifolds 244 and 246 at the second lateral side 204. Additionally and/or alternatively, end caps or plugs (see FIG. 11 ) may be inserted into or otherwise disposed over the ports 342 and 346 of the panel assembly 300 adjacent to the first lateral side 202 to close the manifolds 244 and 246 at the first lateral side 202, and may be inserted into or otherwise disposed over the ports 340 and 348 of the panel assembly 300 adjacent to the second lateral side 204 to close the manifolds 244 and 246 at the second lateral side 204.
The conduits 250 and 256 extend between the end plate 218 and the end panel assembly 300 at the first lateral side 202. The conduits 252 and 254 extend between the end plate 220 and the end panel assembly 300 at the second lateral side 204. The conduits 250 and 256 may extend through the end plate 218 to respectively define the inlet 236 or the outlet 234, may be coupled to the respective inlet 236 or outlet 234 that is defined by the end plate 218, or may be made integral with the end plate 218 and the respective inlet 236 or outlet 234 defined by the end plate 218. The conduits 252 and 254 may extend through the end plate 220 to respectively define the outlet 238 or the inlet 232, may be coupled to the respective outlet 238 or inlet 232 that is defined by the end plate 220, or may be made integral with the end plate 220 and the respective outlet 238 or inlet 232 defined by the end plate 220.
Referring now to FIG. 11 , operation of the three-way heat exchanger 200 will now be described. FIG. 11 is a schematic showing an interior view of the three-way heat exchanger 200 to depict flow of liquid desiccant and the heat transfer fluid through the manifolds 242-248 and the panel assemblies 300. In the schematic of FIG. 11 , panel assemblies 300 are depicted with features exaggerated and/or simplified for convenience of illustration and description.
In operation of the heat exchanger 200, an inlet air stream (e.g., the first or second inlet air stream 110 or 114 shown in FIG. 1 ) enters via the airflow inlet 224 and flows through the air gaps 216 defined between adjacent panel assemblies 300 in the longitudinal direction. The air flowing through the air gaps 216 is treated by liquid desiccant, indicated by the flow lines 344, and heat transfer fluid, indicated by the flow lines 350, that are channeled through each of the panel assemblies 300. In some operations, the liquid desiccant 344 is concentrated liquid desiccant 152 from the liquid desiccant circuit 108 and the heat transfer fluid 350 is conditioner heat transfer fluid from the conditioner sub-system 104 shown in FIG. 1 , and the heat exchanger 200 is used to cool and dehumidify the air flowing through the air gaps 216. In other operations, the liquid desiccant 344 is diluted liquid desiccant 154 from the liquid desiccant circuit 108 and the heat transfer fluid 350 is regenerator heat transfer fluid from the regenerator sub-system 106 shown in FIG. 1 , and the heat exchanger 200 is used to heat and reject moisture into the air flowing through the air gaps 216.
The liquid desiccant 344 flows into the liquid desiccant inlet manifold 242 from the first lateral side 202, via the liquid desiccant inlet 236 and the conduit 250 (shown in FIGS. 3-5 ). The inlet manifold 242 is capped or plugged at the second lateral side 204 by an end cap 270 to restrict liquid desiccant 344 from flowing out from the manifold 242 at this lateral end. Alternatively, the end plate 220 of the heat exchanger 200 may plug the inlet manifold 242 at the second lateral side 204. The liquid desiccant 344 enters into the liquid desiccant header area 320 of each panel assembly 300 from the liquid desiccant inlet manifold 242 via the apertures 356. In each panel assembly 300, the liquid desiccant 344 flows from the liquid desiccant header area 320, into the liquid desiccant channels 336 and 338 via the apertures 360 on each plate 326 and 328 (shown in FIGS. 7 and 8 ), downward through the liquid desiccant channels 336 and 338, and into the liquid desiccant header area 322 via the apertures 362 on each plate 326 and 328 (shown in FIGS. 7 and 8 ). As the liquid desiccant 344 flows behind the membranes 332 and 334 of the panel assemblies 300, the liquid desiccant 344 absorbs moisture from or desorbs moisture into the air flowing through the air gaps 216 adjacent to the membranes 332 and 334. Moisture is permitted to permeate through each of the membranes 332 and 334 to enable the moisture to transfer between the liquid desiccant 344 and air in the air gaps 216. The liquid desiccant 344, having absorbed or desorbed moisture, exits each panel assembly 300 from the respective liquid desiccant header area 322 via the apertures 358, and flows through the liquid desiccant outlet manifold 244 toward the second lateral side 204. The outlet manifold 244 is capped or plugged at the first lateral side 202 by an end cap 272 to restrict liquid desiccant 344 from flowing out from the manifold 244 at this lateral end. Alternatively, the end plate 218 of the heat exchanger 200 may plug the outlet manifold 244 at the first lateral side 202. The liquid desiccant 344 exits the heat exchanger 200 via the conduit 252 and the liquid desiccant outlet 238 (shown in FIG. 5 ).
The heat transfer fluid 350 flows into the heat transfer fluid inlet manifold 246 from the second lateral side 204, via the heat transfer fluid inlet 232 and the conduit 254 (shown in FIGS. 4 and 5 ). The heat transfer fluid 350 enters into each panel assembly 300 from the heat transfer fluid inlet manifold 246 via the apertures 352. The inlet manifold 246 is capped or plugged at the first lateral side 202 by an end cap 274 to restrict heat transfer fluid 350 from flowing out from the manifold 246 at this lateral end. Alternatively, the end plate 218 of the heat exchanger 200 may plug the inlet manifold 246 at the first lateral side 202. In each panel assembly 300, the heat transfer fluid 350 flows upward through the heat transfer fluid channel 330. The heat transfer fluid 350 flowing through the channel 330 is in thermal communication with the liquid desiccant 344 flowing through the liquid desiccant channels 336 and 338. Heat is transferred between the heat transfer fluid 350 and the liquid desiccant 344 to remove heat from or reject heat into the air flowing through the air gaps 216, depending on the operating mode of the heat exchanger 200. The heat transfer fluid 350, having absorbed or rejected heat, exits each panel assembly 300 via the apertures 354, and flows through the heat transfer fluid outlet manifold 248 toward the first lateral side 202. The outlet manifold 248 is capped or plugged at the second lateral side 204 by an end cap 276 to restrict heat transfer fluid 350 from flowing out from the manifold 248 at this lateral end. Alternatively, the end plate 220 of the heat exchanger 200 may plug the outlet manifold 248 at the second lateral side 204. The heat transfer fluid 350 exits the heat exchanger 200 via the conduit 256 and the heat transfer fluid outlet 234 (shown in FIGS. 3-5 ).
The direction of flow of the heat transfer fluid 350 and the liquid desiccant 344 in the illustrated embodiment is by way of example only, and may change in other embodiments of the heat exchanger 200. For example, the liquid desiccant 344 may flow upward through the desiccant channels 336 and 338 on the panel assemblies 300. In these examples, the direction of flow of the liquid desiccant 344 through the liquid desiccant inlet 236 and outlet 238 and the liquid desiccant inlet and outlet manifolds 242 and 244 would also be reversed. The heat transfer fluid 350 may flow downward through the heat transfer channels 330 of the panel assemblies 300. In these examples, the direction of flow of the heat transfer fluid 350 through the heat transfer fluid inlet and outlets 232 and 234 and the heat transfer fluid inlet and outlet manifolds 246 and 248 would also be reversed. The liquid desiccant 344 and the heat transfer fluid 350 flow in counter-flow relation in the illustrated example, but may flow in the same direction through the panel assemblies in alternative examples.
Still referring to FIG. 11 , the heat transfer fluid 350 flowing through the heat transfer fluid inlet manifold 246 may have the propensity to flow primarily through the panel assemblies 300 proximate to the second lateral side 204 of the three-way heat exchanger 200, where the heat transfer fluid inlet 232 is located. As heat transfer fluid 350 enters into the panel assemblies 300 along the lateral extent of the heat transfer fluid inlet manifold 246, the pressure of the heat transfer fluid 350 in the inlet manifold 246 decreases and the flow rate of the heat transfer fluid 350 may be reduced in the panel assemblies 300 proximate to the first lateral side 202 of the heat exchanger 200 relative to the flow rate of the heat transfer fluid 350 in the panel assemblies 300 proximate to the second lateral side 204. The liquid desiccant 344 flowing through the liquid desiccant inlet manifold 242 may have the propensity to flow primarily through the panel assemblies 300 proximate to the first lateral side 202 of the three-way heat exchanger 200, where the liquid desiccant inlet 236 is located. As liquid desiccant 344 enters into the panel assemblies 300 along the lateral extent of the liquid desiccant inlet manifold 242, the pressure of the liquid desiccant 344 in the inlet manifold 242 decreases and the flow rate of the liquid desiccant 344 may be reduced in the panel assemblies 300 proximate to the second lateral side 204 of the heat exchanger 200 relative to the flow rate in the panel assemblies 300 proximate to the first lateral side 202. This may result in mal-distribution of the heat transfer fluid 350 and the liquid desiccant 344 across the panel assemblies 300, which degrades the performance of the heat exchanger 200 and the capability to provide sensible and/or latent cooling of air flowing through the air gaps 216. The mal-distribution problem experienced in the panel assemblies 300 may be exacerbated at lower flow rates (e.g., less than 10 liters per minute).
An advantage provided by the three-way heat exchanger 200 is that the respective connection of the heat transfer fluid inlet 232 and outlet 234 to the heat transfer fluid inlet and outlet manifolds 246 and 248 on opposite lateral sides 204 and 202 of the heat exchanger 200 facilitates improving the flow distribution of the heat transfer fluid 350 across the panel assemblies 300. As the heat transfer fluid outlet 234 is connected to the heat transfer fluid outlet manifold 248 at the first lateral side 202 of the heat exchanger 200, the flow rate of the heat transfer fluid 350 in the outlet manifold 248 is greater at the first lateral side 202 than the second lateral side 204. This decreases a pressure differential through the heat transfer fluid channel 330 of the panel assemblies 300 between the inlet and outlet manifolds 246 and 248 proximate the second lateral side 204 and increases the pressure differential through the heat transfer fluid channel 330 of the panel assemblies 300 between the inlet and outlet manifolds 246 and 248 proximate the first lateral side 202. This reduces the propensity of the heat transfer fluid 350 in the heat transfer fluid inlet manifold 246 to flow primarily through the panel assemblies 300 proximate to the second lateral side 204 and directs the heat transfer fluid 350 in the inlet manifold 246 towards the first lateral side 202. As a result, flow of the heat transfer fluid 350 is more uniformly distributed across the panel assemblies 300. The respective connection of the liquid desiccant inlet 236 and outlet 238 to the liquid desiccant inlet and outlet manifolds 242 and 244 on opposite lateral sides 202 and 204 of the heat exchanger 200 may also facilitate improving the flow distribution of the liquid desiccant 344 across the panel assemblies 300 as described for the heat transfer fluid 350.
The flow distribution of the liquid desiccant 344 across the panel assemblies 300 may additionally and/or alternatively be controlled by adjusting the size, shape, and/or number of apertures 360 and 362 that are included in each plate 326 and 328. As described above, the liquid desiccant 344 flows between the liquid desiccant header area 320 and the liquid desiccant channels 336 and 338 via the apertures 360 in the plates 326 and 328, respectively, and the liquid desiccant 344 flows between the liquid desiccant channels 336 and 338 and the liquid desiccant header area 322 via the apertures 362 in the plates 326 and 328, respectively. The size, shape, and/or number of the apertures 360 and/or 362 in the plates 326 and 328 of the panel assemblies 300 proximate the first lateral side 202 may be adjusted to limit flow of the liquid desiccant 344 into the respective membrane channels 336 and 338, directing the liquid desiccant 344 towards the panel assemblies 300 proximate the second lateral side 204. For example, the plates 326 and 328 of the panel assemblies 300 proximate the first lateral side 202 may have smaller diameter apertures 360 and/or 362, or fewer apertures 360 and/or 362, than the plates 326 and 328 of the panel assemblies 300 proximate the second lateral side 204 to direct the liquid desiccant 344 towards the panel assemblies 300 proximate the second lateral side 204.
Referring to FIGS. 12-14 , the three-way heat exchanger 200 may include additional and/or alternative features that direct the heat transfer fluid 350 and the liquid desiccant 344 in the respective inlet manifolds 246 and 242 respectively towards the first and second lateral sides 202 and 204 of the heat exchanger 200 to facilitate uniform flow distribution of the heat transfer fluid 350 and the liquid desiccant 344 through the panel assemblies 300. FIGS. 12-14 each illustrate a schematic interior view of the three-way heat exchanger 200 similar to FIG. 11 . The features shown in FIGS. 12-14 to facilitate uniform flow distribution of the heat transfer fluid 350 and the liquid desiccant 344 may be used in isolation or in any combination and are not limited to the example illustrated embodiments. In some examples, the features may be included to facilitate uniform flow distribution of only the heat transfer fluid 350 across the panel assemblies 300 or only the liquid desiccant 344 across the panel assemblies 300.
FIG. 12 depicts an example where the dimensions of the apertures 352 (shown in FIG. 10B) that connect the heat transfer fluid inlet ports 346 of the panel assemblies 300 to the heat transfer fluid channel 330 and the apertures 356 (shown in FIG. 10C) that connect the liquid desiccant inlet ports 340 of the panel assemblies 300 to the first liquid desiccant header areas 320 vary between the panel assemblies 300 to respectively direct the heat transfer fluid 350 in the inlet manifold 246 towards the first lateral side 202 and the liquid desiccant 344 in the inlet manifold 242 towards the second lateral side 204. In the illustrated example, the apertures 352 increase in diameter along the lateral extent of the inlet manifold 246 towards the first lateral side 202 and the apertures 356 increase in diameter along the lateral extent of the inlet manifold 242 towards the second lateral side 204. The smaller diameter apertures 352 proximate the second lateral side 204 limit flow of the heat transfer fluid 350 from the inlet manifold 246 into the respective heat transfer fluid channel 330, directing the heat transfer fluid 350 towards the panel assemblies 300 proximate the first lateral side 202. The smaller diameter apertures 356 proximate the first lateral side 202 limit flow of the liquid desiccant 344 from the inlet manifold 242 into the respective first liquid desiccant header area 320, directing the liquid desiccant 344 towards the panel assemblies 300 proximate the second lateral side 204. Dimensions other than the diameter of the apertures 352 and 356 may vary between the panel assemblies 300 to respectively direct the heat transfer fluid 350 in the inlet manifold 246 towards the first lateral side 202 and the liquid desiccant 344 in the inlet manifold 242 towards the second lateral side 204. For example, the number, size, and/or shape of the apertures 352 and 356 may vary between the panel assemblies 300. In some examples, the apertures 352 proximate the second lateral side 204 and/or the apertures 356 proximate the first lateral side 202 may be bell-mouthed to limit fluid flow therethrough and the apertures 352 proximate the first lateral side 202 and/or the apertures 356 proximate the second lateral side 204 may be substantially cylindrical or have a wider mouth shape to allow relatively greater fluid flow therethrough. In some examples, a greater number of apertures 352 may be included in the panel assemblies 300 proximate the first lateral side 202 than in the panel assemblies 300 proximate the second lateral side 204 and/or a greater number of apertures 356 may be included in the panel assemblies 300 proximate the second lateral side 204 than in the panel assemblies 300 proximate the first lateral side 202.
In some examples, the dimensions (e.g., the number, size, and/or shape) of only the apertures 352 may vary between panel assemblies 300, and the dimensions of the apertures 356 are substantially the same between panel assemblies. In other examples, the dimensions (e.g., the number, size, and/or shape) of only the apertures 356 may vary between panel assemblies 300, and the dimensions of the apertures 352 are substantially the same between panel assemblies.
FIG. 13 depicts an example where an insert 364 is disposed within the heat transfer fluid inlet manifold 246 to direct the heat transfer fluid 350 in the inlet manifold 246 towards the first lateral side 202 and an insert 366 is disposed within the liquid desiccant inlet manifold 242 to direct the liquid desiccant 344 in the inlet manifold 242 towards the second lateral side 204. Each of the inserts 364 and 366 reduces a cross-sectional area of the respective inlet manifold 246 and 242 to respectively direct the heat transfer fluid 350 and the liquid desiccant 344. The insert 364 reduces the cross-sectional area of the inlet manifold 246 towards the first lateral side 202 to maintain the pressure and flow rate of the heat transfer fluid 350 in the inlet manifold 246 as a portion exits into the panel assemblies 300 proximate the second lateral side 204. The insert 366 reduces the cross-sectional area of the inlet manifold 242 towards the second lateral side 204 to maintain the pressure and flow rate of the liquid desiccant 344 in the inlet manifold 242 as a portion exits into the panel assemblies 300 proximate the first lateral side 202.
The inserts 364 and 366 may have any suitable shape that enables the inserts to function as described. For example, the inserts may be stepped or gradually tapered to reduce the cross-sectional area in the respective inlet manifold 246 and 242. The inserts 364 and 366 may have, for example, a stepped or gradual conical profile, a stepped or gradual frustum profile (e.g., frusto-conical), a stepped or gradual hemispheric profile, or another suitable profile. In some examples, only one of the inserts 364 and 366 may be included in its respective inlet manifold.
The inserts 364 and 366 may be made integral with the end caps 274 and 270, respectively, and inserted into the respective inlet manifolds 246 and 242 when the end caps 274 and 270 are installed. Alternatively, the inserts 364 and 366 may be inserted and fixed within the respective inlet manifolds 246 and 242 using any suitable means. Inserts may additionally and/or alternatively be included in the outlet manifolds 244 and 248. For example, an insert may be included in the heat transfer fluid outlet manifold 248 to decrease pressure and flow rate of the heat transfer fluid 350 towards the first lateral side 202 (and/or increase pressure of the heat transfer fluid 350 towards the second lateral side 204). An insert may be included in the liquid desiccant outlet manifold 244 to decrease pressure and flow rate of the liquid desiccant 344 towards the second lateral side 204 (and/or increase pressure of the liquid desiccant 344 towards the first lateral side 202). Inserts included in the outlet manifolds 244 and 248 may reduce the cross-sectional area therein towards the second lateral side 204 and the first lateral side 202, respectively. The inserts included in the outlet manifolds 244 and 248 may be made integral with the end caps 272 and 276, respectively, and inserted into the respective outlet manifolds when the end caps 272 and 276 are installed, or may be inserted and fixed within the respectively outlet manifolds using any suitable means.
FIG. 14 depicts another example where an insert 368 is disposed within the heat transfer fluid inlet manifold 246 to direct the heat transfer fluid 350 in the inlet manifold 246 towards the first lateral side 202 and an insert 378 is disposed within the liquid desiccant inlet manifold 242 to direct the liquid desiccant 344 in the inlet manifold 242 towards the second lateral side 204. The inserts 368 and 378 are each deflectors or screens located in the respective manifolds 246 and 242 proximate to the second lateral side 204 and the first lateral side 202, respectively. The insert 368 deflects or otherwise limits heat transfer fluid 350 in the manifold 246 from flowing into the panel assemblies 300 proximate to the second lateral side 204, driving the heat transfer fluid 350 towards the first lateral side 202. The insert 378 deflects or otherwise limits liquid desiccant 344 in the manifold 242 from flowing into the panel assemblies 300 proximate to the first lateral side 202, driving the liquid desiccant 344 towards the second lateral side 204. In some examples, only one of the inserts 368 and 378 may be included in its respective inlet manifold.
Example HVAC systems described include one or more air treatment sub-systems for removing heat and moisture from a flow of air and/or rejecting heat and moisture into a flow of air. An example air treatment sub-system includes a three-way heat exchanger including panel assemblies arranged in succession and defining air gaps for air to flow therebetween. Heat transfer fluid and liquid desiccant are channeled through each panel assembly to treat the air flowing through the air gaps. The operational efficiency of the three-way heat exchanger is improved by configurations and/or features that facilitate more uniform distribution of the heat transfer fluid and/or liquid desiccant across the panel assemblies of the heat exchanger. For example, a fluid inlet and outlet for the heat transfer fluid and/or liquid desiccant are located on opposite lateral sides of the heat exchanger to maintain uniform pressure differentials of the fluids flowing through the panel assemblies. Additionally and/or alternatively, the heat transfer fluid and/or liquid desiccant may be driven toward later stage panel assemblies using various components and features described herein.
Example embodiments of HVAC systems and methods of operating the systems are described above in detail. The systems and methods are not limited to the specific embodiments described herein, but rather, components of the system and methods may be used independently and separately from other components described herein. For example, the systems described herein may be used in systems other than HVAC systems.
When introducing elements of the present disclosure or the embodiment(s) thereof, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” “containing” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. The use of terms indicating a particular orientation (e.g., “top”, “bottom”, “side”, “vertical”, “lateral”, “longitudinal”, etc.) is for convenience of description and does not require any particular orientation of the item described.
As various changes could be made in the above constructions and methods without departing from the scope of the disclosure, it is intended that all matter contained in the above description and shown in the accompanying drawing(s) shall be interpreted as illustrative and not in a limiting sense.

Claims

What is claimed is:

1. A heating, ventilation, and air conditioning (HVAC) system comprising:

a refrigerant sub-system; and

at least one air treatment sub-system comprising a three-way heat exchanger for transferring heat between a heat transfer fluid, a liquid desiccant, and air, the HVAC system operable to circulate the heat transfer fluid between the three-way heat exchanger and the refrigerant sub-system;

wherein the three-way heat exchanger defines mutually perpendicular lateral, longitudinal, and vertical directions, the three-way heat exchanger comprising:

panel assemblies arranged in succession in the lateral direction, airflow gaps being defined between adjacent panel assemblies to allow the air to flow through the three-way heat exchanger, each panel assembly comprising a frame defining a heat transfer fluid channel and at least one vapor-permeable membrane disposed on a lateral face of the frame, at least one desiccant channel being defined between the at least one membrane and the frame, the at least one desiccant channel being separated from the heat transfer fluid channel;

a heat transfer fluid inlet manifold and a heat transfer fluid outlet manifold, the heat transfer fluid inlet and outlet manifolds being connected to the heat transfer fluid channel of each panel assembly, the heat transfer fluid inlet and outlet manifolds each extending between first and second lateral sides of the three-way heat exchanger, the heat transfer fluid inlet manifold being closed at the first lateral side and the heat transfer fluid outlet manifold being closed at the second lateral side; and

a heat transfer fluid inlet connected to the heat transfer fluid inlet manifold at the second lateral side and a heat transfer fluid outlet connected to the heat transfer fluid outlet manifold at the first lateral side.

2. The HVAC system of claim 1, wherein the three-way heat exchanger has first and second longitudinal sides and first and second vertical sides, and wherein the heat transfer fluid inlet manifold extends laterally proximate to the second longitudinal side and the second vertical side and the heat transfer fluid outlet manifold extends laterally proximate to the first longitudinal side and the first vertical side.

3. The HVAC system of claim 2, wherein the first longitudinal side of the three-way heat exchanger defines an airflow inlet and the second longitudinal side of the three-way heat exchanger defines an airflow outlet, and wherein the airflow gaps defined between adjacent panel assemblies are in communication with the airflow inlet and outlet to allow the air to flow through the three-way heat exchanger in the longitudinal direction.

4. The HVAC system of claim 3, wherein the heat transfer fluid inlet and the heat transfer fluid outlet are located at the second longitudinal side of the three-way heat exchanger, the heat transfer fluid inlet being connected to the heat transfer fluid inlet manifold by a first longitudinally-extending conduit and the heat transfer fluid outlet being connected to the heat transfer fluid outlet manifold by a second longitudinally-extending conduit.

5. The HVAC system of claim 1, wherein the three-way heat exchanger further comprises:

a liquid desiccant inlet manifold and a liquid desiccant outlet manifold, the liquid desiccant inlet and outlet manifolds being connected to the at least one desiccant channel of each panel assembly, the liquid desiccant inlet and outlet manifolds each extending between the first and second lateral sides of the three-way heat exchanger, the liquid desiccant inlet manifold being closed at the second lateral side and the liquid desiccant outlet manifold being closed at the first lateral side; and

a liquid desiccant inlet connected to the liquid desiccant inlet manifold at the first lateral side and a liquid desiccant outlet connected to the liquid desiccant outlet manifold at the second lateral side.

6. The HVAC system of claim 5, wherein the three-way heat exchanger has first and second longitudinal sides and first and second vertical sides, wherein the heat transfer fluid inlet manifold extends laterally proximate to the second longitudinal side and the second vertical side, the heat transfer fluid outlet manifold extends laterally proximate to the first longitudinal side and the first vertical side, the liquid desiccant inlet manifold extends laterally proximate to the second longitudinal side and the first vertical side, and the liquid desiccant outlet manifold extends laterally proximate to the first longitudinal side and the second vertical side.

7. The HVAC system of claim 1, wherein the three-way heat exchanger comprises an insert disposed within the heat transfer fluid inlet manifold, the insert configured to direct a flow of the heat transfer fluid through the heat transfer fluid inlet manifold towards the first lateral side.

8. The HVAC system of claim 7, wherein the insert reduces a cross-sectional area of the heat transfer fluid inlet manifold towards the first lateral side to direct the flow of the heat transfer fluid through the heat transfer fluid inlet manifold towards the first lateral side.

9. The HVAC system of claim 1, wherein, for each panel assembly, the heat transfer fluid inlet manifold is connected to the heat transfer fluid channel by at least one heat transfer fluid inlet aperture, and wherein the heat transfer fluid inlet apertures of the panel assemblies have different dimensions to direct a flow of the heat transfer fluid through the heat transfer fluid inlet manifold towards the first lateral side.

10. A heating, ventilation, and air conditioning (HVAC) system comprising:

a refrigerant sub-system;

a conditioner sub-system comprising a first three-way heat exchanger for transferring heat between a conditioner heat transfer fluid, a liquid desiccant, and a first air stream, the HVAC system operable to circulate the conditioner heat transfer fluid between the first three-way heat exchanger and the refrigerant sub-system; and

a regenerator sub-system comprising a second three-way heat exchanger for transferring heat between a regenerator heat transfer fluid, the liquid desiccant, and a second air stream, the HVAC system operable to circulate the regenerator heat transfer fluid between the second three-way heat exchanger and the refrigerant sub-system;

wherein the first and second three-way heat exchangers each define mutually perpendicular lateral, longitudinal, and vertical directions, each three-way heat exchanger comprising:

panel assemblies arranged in succession in the lateral direction, airflow gaps being defined between adjacent panel assemblies to allow the respective air stream to flow through the three-way heat exchanger, each panel assembly comprising a frame defining a heat transfer fluid channel and at least one vapor-permeable membrane disposed on a lateral face of the frame, at least one desiccant channel being defined between the at least one membrane and the frame, the at least one desiccant channel being separated from the heat transfer fluid channel;

11. The HVAC system of claim 10, wherein, for each three-way heat exchanger:

the three-way heat exchanger has first and second longitudinal sides and first and second vertical sides;

the heat transfer fluid inlet manifold extends laterally proximate to the second longitudinal side and the second vertical side and the heat transfer fluid outlet manifold extends laterally proximate to the first longitudinal side and the first vertical side;

the first longitudinal side of the three-way heat exchanger defines an airflow inlet and the second longitudinal side of the three-way heat exchanger defines an airflow outlet, and wherein the airflow gaps defined between adjacent panel assemblies are in communication with the airflow inlet and outlet to allow the respective air stream to flow through the three-way heat exchanger in the longitudinal direction; and

the heat transfer fluid inlet and the heat transfer fluid outlet are located at the second longitudinal side of the three-way heat exchanger, the heat transfer fluid inlet being connected to the heat transfer fluid inlet manifold by a first longitudinally-extending conduit and the heat transfer fluid outlet being connected to the heat transfer fluid outlet manifold by a second longitudinally-extending conduit.

12. The HVAC system of claim 10, wherein each three-way heat exchanger further comprises:

13. The HVAC system of claim 10, wherein each three-way heat exchanger comprises an insert disposed within the heat transfer fluid inlet manifold, the insert configured to direct a flow of the respective heat transfer fluid through the heat transfer fluid inlet manifold towards the first lateral side.

14. The HVAC system of claim 10, wherein, for each panel assembly of each three-way heat exchanger, the heat transfer fluid inlet manifold is connected to the heat transfer fluid channel by at least one heat transfer fluid inlet aperture, and wherein the heat transfer fluid inlet apertures of the panel assemblies have different dimensions to direct a flow of the respective heat transfer fluid through the heat transfer fluid inlet manifold towards the first lateral side.

15. A three-way heat exchanger for use in an air treatment sub-system of a heating, ventilation, and air conditioning system, the three-way heat exchanger operable to transfer heat between a heat transfer fluid, a liquid desiccant, and air, the three-way heat exchanger defining mutually perpendicular lateral, longitudinal, and vertical directions, the three-way heat exchanger comprising:

16. The three-way heat exchanger of claim 15, wherein the heat transfer fluid inlet manifold extends laterally proximate to a second longitudinal side of the three-way heat exchanger and a second vertical side of the three-way heat exchanger and the heat transfer fluid outlet manifold extends laterally proximate to a first longitudinal side of the three-way heat exchanger and a first vertical side of the three-way heat exchanger.

17. The three-way heat exchanger of claim 16, further comprising:

18. The three-way heat exchanger of claim 17, wherein the liquid desiccant inlet manifold extends laterally proximate to the second longitudinal side and the first vertical side, and the liquid desiccant outlet manifold extends laterally proximate to the first longitudinal side and the second vertical side.

19. The three-way heat exchanger of claim 15, further comprising an insert disposed within the heat transfer fluid inlet manifold, the insert configured to direct a flow of the heat transfer fluid through the heat transfer fluid inlet manifold towards the first lateral side.

20. The three-way heat exchanger of claim 15, wherein, for each panel assembly, the heat transfer fluid inlet manifold is connected to the heat transfer fluid channel by at least one heat transfer fluid inlet aperture, and wherein the heat transfer fluid inlet apertures of the panel assemblies have different dimensions to direct a flow of the heat transfer fluid through the heat transfer fluid inlet manifold towards the first lateral side.