Liquid desiccant regeneration system, heating, ventilation and air conditioning system, and method of operating liquid desiccant regeneration system

Abstract

The invention relates to a liquid desiccant regeneration system, a heating, ventilation and air conditioning system, and a method of operating a liquid desiccant regeneration system. The liquid desiccant regeneration system includes a regeneration tank for containing a saturated liquid desiccant and an air diffuser. The regeneration tank has an air inlet, a desiccant inlet, and a desiccant outlet. An air diffuser is positioned within the regeneration tank between the desiccant inlet and the desiccant outlet. The air diffuser is operable to receive the air flow from the air inlet and diffuse the air flow into the saturated liquid desiccant contained in the regeneration tank.

Description

Technical Field

[0001] This field generally relates to heating, ventilation, and air conditioning (HVAC) systems, and more particularly to HVAC systems and methods including a liquid desiccant dehumidification subsystem and a liquid desiccant regeneration subsystem. Background Art

[0002] Heating, ventilation, and air conditioning (HVAC) systems are known for their ability to handle heating, cooling, and moisture removal of outside air circulated through an interior space. The vapor compression cycle is widely used in HVAC systems to condition the temperature and humidity of outside air. Typically, outside air is cooled below its dew point temperature to allow moisture in the air to condense on the evaporator coil, thereby dehumidifying the air. Since this process typically results in the dehumidified air being at an uncomfortably low temperature, the air is then reheated to a more comfortable temperature for the user. The process of overcooling and reheating the air can become very energy-consuming and expensive.

[0003] In some applications, an HVAC system includes a vapor compression system used in combination with a liquid desiccant dehumidification system to remove moisture from outside air without cooling the outside air below its dew point temperature. For example, an HVAC system can include a refrigerant subsystem operating under a vapor compression cycle and an air handling subsystem that uses a heat transfer fluid and a 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 handling subsystem can include a three-way heat transfer device that facilitates sensible cooling and latent cooling of warm outdoor air using the heat transfer fluid and the liquid desiccant.

[0004] In the operation of the three-way heat exchanger, the liquid desiccant and the heat transfer fluid are directed through the heat exchanger, and heat is transferred between the liquid desiccant and the heat transfer fluid. An outside air stream is directed through the heat exchanger, and the heat transfer fluid absorbs heat from the air stream while the liquid desiccant absorbs moisture from the air stream. The liquid desiccant can be circulated between the three-way heat exchanger and a regeneration system, where the diluted liquid desiccant discharges the absorbed moisture into a sacrificial fluid. The refrigerant subsystem engages with the air handling subsystem, whereby the refrigerant absorbs heat from the heat transfer fluid in the three-way heat exchanger during the evaporation stage of the vapor compression cycle. The refrigerant is then directed to a condensation stage, in which the refrigerant discharges the absorbed heat into another fluid. Then, the liquid desiccant treated by the regeneration system and the heat transfer fluid treated by the refrigerant subsystem are directed back toward the three-way heat exchanger to again provide sensible cooling and latent cooling of the outside air.

[0005] Regeneration systems for transferring moisture from a diluted liquid desiccant and producing a concentrated liquid desiccant can be expensive, inefficient in operation or in energy use, and / or have a relatively large footprint. There is a need for a liquid desiccant regeneration system that has a smaller footprint and greater location flexibility to facilitate reducing the costs associated with manufacturing, installation, and / or use, and otherwise to facilitate improving the efficiency of an HVAC system.

[0006] This Background of the Invention section is intended to introduce to the reader various aspects of the 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 is to be understood that these statements are to be read in this light and not as an admission of prior art. Summary of the Invention

[0007] One aspect is a liquid desiccant regeneration system. The liquid desiccant regeneration system includes a regeneration tank for containing a saturated liquid desiccant and an air diffuser. The regeneration tank has an air inlet, a desiccant inlet, and a desiccant outlet. The air diffuser is positioned within the regeneration tank between the desiccant inlet and the desiccant outlet. The air diffuser is operable to receive an air stream from the air inlet and diffuse the air stream into the saturated liquid desiccant contained in the regeneration tank.

[0008] Another aspect is a heating, ventilation, and air conditioning (HVAC) system. The HVAC system includes: a dehumidification subsystem that is operable to transfer moisture between a liquid desiccant and a first air stream; and a regeneration subsystem that is operable to transfer moisture between the liquid desiccant and a second air stream. The HVAC system is operable to circulate a concentrated liquid desiccant to the dehumidification subsystem and circulate a saturated liquid desiccant to the regeneration subsystem. The regeneration subsystem includes a regeneration tank for containing a saturated liquid desiccant and an air diffuser. The regeneration tank has an air inlet, a desiccant inlet, and a desiccant outlet. The air diffuser is positioned within the regeneration tank between the desiccant inlet and the desiccant outlet, wherein the air diffuser is operable to receive a second air stream from the air inlet and diffuse the second air stream into the saturated liquid desiccant contained in the regeneration tank.

[0009] Another aspect is a method of operating a liquid desiccant regeneration system. The method includes: collecting a saturated liquid desiccant in a regeneration tank; supplying an air stream to an air diffuser positioned within the regeneration tank; and using the air diffuser to diffuse the air stream into the saturated liquid desiccant collected in the regeneration tank such that the diffused air stream absorbs moisture from the saturated liquid desiccant.

[0010] There are various improvements to the features pointed out in the above aspects. Other features can also be incorporated into the above aspects. These improvements and additional features can exist alone or in any combination. For example, each of the features discussed below for any of the illustrated embodiments can be incorporated alone or in any combination into any of the above aspects. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a schematic flow chart of a heating, ventilation, and air conditioning (HVAC) system.

[0012] Figure 2 is a schematic flow chart of another HVAC system.

[0013] Figure 3 is an example liquid desiccant regeneration system that can be used in the HVAC systems of Figure 1 and Figure 2 and includes a regeneration tank and an air diffuser.

[0014] Figure 4 is a first example of an air diffuser for use in a liquid desiccant regeneration system of Figure 3

[0015] Figure 5 is a second example of an air diffuser for use in a liquid desiccant regeneration system of Figure 3

[0016] Figure 6 is a third example of an air diffuser for use in a liquid desiccant regeneration system of Figure 3

[0017] Figure 7 is an example method of operating a liquid desiccant regeneration system.

[0018] Throughout the drawings, corresponding reference numerals indicate corresponding components. DETAILED DESCRIPTION

[0019] Figure 1 ​​​is a schematic diagram of a heating, ventilation, and air conditioning (HVAC) system 100. The HVAC system 100 includes subsystems 102-106 and a liquid desiccant loop 108 that facilitate the heating, cooling, and moisture removal capabilities of the system 100. The subsystems of the HVAC system 100 include a refrigerant subsystem 102, a conditioner (or dehumidifier) subsystem 104, and a regenerator (or regenerative) subsystem 106. The conditioner subsystem 104 and the regenerator subsystem 106 can be used to process a first inlet air stream 110 and a second inlet air stream 114, respectively, and may be referred to herein as air handling subsystems 104 and 106. The HVAC system 100 may include additional or other components in addition to those shown and described with reference to Figure 1 the components shown and described therein.

[0020] In an example operating mode of the HVAC system 100, the conditioner subsystem 104 removes heat from the first inlet air stream 110 and directs the conditioned outlet air stream 112 to a conditioned space (not shown), such as the interior of a building structure or a vehicle. The conditioned outlet air stream 112 exiting the conditioner subsystem 104 may have a lower temperature than the first inlet air stream 110. The heat removed from the first inlet air stream 110 is transferred from the conditioner subsystem 104 to the refrigerant subsystem 102. The heat transferred to the refrigerant subsystem 102 may be transferred to a sacrificial fluid (e.g., outdoor air) stream. Additionally and / or alternatively, heat from the refrigerant subsystem 102 may be transferred to the regenerator subsystem 106, which may transfer the heat into the second inlet air stream 114 and direct the heated outlet air stream 116 to the atmosphere.

[0021] The refrigerant subsystem 102 includes an evaporator 118, a condenser 120, a compressor 122, and an expansion valve 124. The compressor 122 can be any suitable compressor, including but not limited to a scroll compressor, a reciprocating compressor, a rotary compressor, a screw compressor, and a centrifugal compressor. The expansion valve 124 can be any suitable expansion valve, such as a thermal expansion valve. The expansion valve 124 can alternatively be any suitable expansion device, such as an orifice or a capillary tube. The refrigerant subsystem 102 also includes a refrigerant loop 126 that circulates a working fluid, such as refrigerant, between the evaporator 118, the compressor 122, the condenser 120, and the expansion valve 124. The refrigerant subsystem 102 may include additional or other components in addition to those shown and described with reference to Figure 1 the components shown and described therein.

[0022] In operation of the refrigerant subsystem 102, refrigerant in loop 126 is directed as low-pressure gaseous refrigerant 128 toward compressor 122. Compressor 122 compresses the gaseous refrigerant 128, which increases the temperature and pressure of the refrigerant. The pressurized, hot gaseous refrigerant 130 exits compressor 122 and is directed toward condenser 120, where the high-pressure gaseous refrigerant 130 is condensed into high-pressure liquid refrigerant 132. The liquid refrigerant 132 exiting condenser 120 is directed toward expansion valve 124, which reduces the pressure of the liquid. The depressurized fluid refrigerant 134, which may be a gas or a mixture of gas and liquid after passing through expansion valve 124, is then directed toward evaporator 118. The fluid refrigerant 134 evaporates into a gas in evaporator 118, thus exiting evaporator 118 as low-pressure gaseous refrigerant 128. The gaseous refrigerant 128 is then directed to return toward compressor 122, where the gaseous refrigerant 128 is compressed again and the process repeats. The circulation of the refrigerant in loop 126 can be driven by compressor 122, and more specifically, by the pressure differential that exists between the pressurized, hot gaseous refrigerant 130 exiting compressor 122 and the low-pressure gaseous refrigerant 128 entering compressor 122. As Figure 1 shown, the flow direction of the refrigerant through loop 126 can be reversed to switch the heat transfer functions of evaporator 118 and condenser 120 and enable the HVAC system 100 to operate in various operating modes.

[0023] The regulator subsystem 104 includes a regulator 136 (e.g., a three-way heat exchanger) and a regulator heat transfer fluid loop 138 that circulates a regulator heat transfer fluid (e.g., water, an ethylene glycol-based fluid, or any combination of water and an ethylene glycol-based fluid) to and from regulator 136. Any suitable number of regulators 136 (e.g., three-way heat exchangers) can be included in the regulator subsystem 104. In the case where the regulator subsystem 104 includes multiple regulators 136, the regulators can operate in series, in parallel, or in any combination of series and parallel.

[0024] Example three-way heat exchangers that can be used as regulator 136 are described in U.S. Patent Application No. 18 / 482,454, filed on October 6, 2023, U.S. Patent Application No. 18 / 490,984, filed on October 20, 2023, U.S. Patent Application No. 18 / 585,344 (Docket No. COP-23-049US01), titled "THREE-WAY HEAT EXCHANGE MODULE WITH CONTROLLED FLUID FLOW", filed on December 20, 2023, U.S. Patent Application No. 18 / 390,475, filed on December 20, 2023, U.S. Patent Application No. 18 / 390,941, filed on December 20, 2023, U.S. Patent Application No. 18 / 390,948, filed on December 20, 2023, and U.S. Patent Application No. 18 / 391,384, filed on December 20, 2023. The disclosures of these U.S. patent applications are hereby incorporated by reference in their entirety.

[0025] The regulator subsystem 104 is engaged with the refrigerant subsystem 102 via the evaporator 118. In particular, the evaporator 118 is included in the refrigerant loop 126 and the regulator heat transfer loop 138, and facilitates the transfer of heat from the regulator heat transfer fluid in the loop 138 to the flowing refrigerant 134 in the refrigerant loop 126. The regulator subsystem 104 may include additional or other components in addition to those shown and described with reference to Figure 1 those shown and described. For example, the regulator subsystem 104 may include one or more pumps (not shown) for circulating the regulator heat transfer fluid in the loop 138 between the regulator 136 and the evaporator 118. Suitable pumps that may be included in the regulator subsystem 104 include, for example, centrifugal pumps, diaphragm pumps, positive displacement pumps, or any type of pump suitable for transferring liquids. Depending on the operating requirements of the HVAC system 100 and other factors (such as the temperature and / or humidity of the first air inlet stream 110), the regulator subsystem 104 may include additional heat transfer devices for transferring heat from the regulator heat transfer fluid to the atmosphere or from the atmosphere to the regulator heat transfer fluid.

[0026] In the operation of the conditioner subsystem 104, the conditioner heat transfer fluid in loop 138 is directed 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 to the liquid refrigerant 134 in loop 126 to produce gaseous refrigerant 128. The cooled conditioner heat transfer fluid 140 exiting the evaporator 118 is directed toward and enters the conditioner 136. A first inlet air stream 110 is also directed through the conditioner 136. The conditioner 136 transfers heat from the first inlet air stream 110 to the conditioner heat transfer fluid 140, thereby heating the conditioner heat transfer fluid. The heated conditioner heat transfer fluid 142 exiting the conditioner 136 is directed to return toward the evaporator 118, and the process is repeated.

[0027] The regenerator subsystem 106 includes a regenerator 144 and a regenerator heat transfer fluid loop 146 that circulates a regenerator heat transfer fluid (e.g., water, an ethylene glycol-based fluid, or any combination of water and an ethylene glycol-based fluid) to and from a heater 158 that is thermally connected to the regenerator 144. Any suitable number of regenerators 144 and / or heaters 158 may be included in the regenerator subsystem 106. In cases where the regenerator subsystem 106 includes multiple regenerators 144 and / or heaters 158, the regenerators or heaters may operate in series, in parallel, or in any combination of series and parallel. The heater 158 may include heating coils positioned within the regenerator 144 and / or a heating jacket surrounding the regenerator 144. In the exemplary HVAC system 100, the regenerator subsystem 106 is engaged with the refrigerant subsystem 102 via the condenser 120. In particular, the condenser 120 is included in both the refrigerant loop 126 and the regenerator heat transfer loop 146 and facilitates the transfer of heat from the pressurized gaseous refrigerant 130 in the refrigerant loop 126 to the regenerator heat transfer fluid. The regenerator subsystem 106 may include additional or other components in addition to those shown and described with reference to Figure 1 those shown and described. For example, the regenerator subsystem 106 may include one or more pumps (not shown) for circulating the regenerator heat transfer fluid in loop 146 between the regenerator 144 and the condenser 120. Suitable pumps that may be included in the regenerator subsystem 106 include, for example, centrifugal pumps, diaphragm pumps, positive displacement pumps, or any type of pump suitable for transferring liquids. Depending on the operating requirements of the HVAC system 100 and other factors (e.g., the temperature and / or humidity of the first air inlet stream 110), the regenerator subsystem 106 may include additional heat transfer devices for transferring heat from the atmosphere to the regenerator heat transfer fluid or from the regenerator heat transfer fluid to the atmosphere.

[0028] In the operation of the regenerator subsystem 106, the regenerator heat transfer fluid in loop 146 is directed toward the condenser 120. The regenerator heat transfer fluid is heated in the condenser 120 as heat is transferred from the pressurized gaseous refrigerant 130 in loop 126 to the regenerator heat transfer fluid to produce the liquid refrigerant 132. The heated regenerator heat transfer fluid 148 leaving the condenser is directed toward the regenerator 144 and enters the heater 158. A second inlet air stream 114 is also directed through the regenerator 144. The heater 158 is operative to transfer heat from the regenerator heat transfer fluid to the second inlet air stream 114, thereby cooling the regenerator heat transfer fluid. The heated outlet air stream 116 leaving the regenerator 144 has a higher temperature than the second inlet air stream 114. The cooled regenerator heat transfer fluid 150 leaving the regenerator 144 is directed to return toward the condenser 120, and the process is repeated.

[0029] The HVAC system 100 also includes a liquid desiccant loop 108 that operates in conjunction with the subsystems 102 to 106 to facilitate cooling of the first inlet air stream 110 by latent heat cooling and sensible heat cooling. The liquid desiccant loop 108 includes a liquid desiccant directed between the conditioner 136 and the regenerator 144. Suitable liquid desiccants that may be used in the liquid desiccant loop 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.

[0030] The liquid desiccant loop 108 may include one or more pumps (not shown) for directing the liquid desiccant between the conditioner 136 and the regenerator 144. Suitable pumps that may be included in the liquid desiccant loop 108 include, for example, centrifugal pumps, diaphragm pumps, positive displacement pumps, or any type of pump suitable for transferring liquids. The liquid desiccant loop 108 may include one or more pumps for transferring the concentrated liquid desiccant 152 from the regenerator 144 toward the conditioner 136, and one or more pumps for transferring the diluted (or saturated) liquid desiccant 154 from the conditioner 136 toward the regenerator 144.

[0031] The concentrated liquid desiccant 152 in the liquid desiccant circuit 108 is directed towards the conditioner 136 of the conditioner subsystem 104, where the concentrated liquid desiccant 152 removes moisture from the first inlet air stream 110. The concentrated liquid desiccant 152 is combined with the cooled conditioner heat transfer fluid 140 in the conditioner 136 to absorb heat and moisture from the first inlet air stream 110. The conditioned outlet air stream 112 leaving the conditioner 136 may have lower humidity and / or lower temperature compared to the first inlet air stream 110. The liquid desiccant that has absorbed moisture from the first inlet air stream 110 leaves the conditioner 136 as a diluted (or saturated) liquid desiccant 154.

[0032] The diluted (or saturated) liquid desiccant 154 is directed towards the regenerator 144 of the regenerator subsystem 106, where the diluted liquid desiccant 154 discharges moisture into the second inlet air stream 114. The diluted liquid desiccant 154 is combined with the heated regenerator heat transfer fluid 148 directed to the heater 158 to discharge heat and moisture into the second inlet air stream 114. Thus, the heated outlet air stream 116 leaving the regenerator 144 has greater humidity and higher temperature compared to the second inlet air stream 114. The liquid desiccant that has discharged moisture into the second inlet air stream 114 leaves the regenerator subsystem 106 as a concentrated liquid desiccant 152. The concentrated liquid desiccant 152 leaving the regenerator 144 is directed to return towards the conditioner 136, and the process is repeated.

[0033] The liquid desiccant loop 108 may also include a desiccant-desiccant heat exchanger 156 that transfers heat from the concentrated liquid desiccant 152 that has exited the regenerator 144 to the diluted (or saturated) liquid desiccant 154 that has exited the conditioner 136. The desiccant-desiccant heat exchanger 156 may facilitate improving the functionality of the liquid desiccant in the conditioner 136 and the regenerator 144. For example, the desiccant-desiccant heat exchanger 156 may reduce the temperature of the concentrated liquid desiccant 152 to provide greater cooling and dehumidification capabilities of the conditioner 136. Additionally and / or alternatively, the desiccant-desiccant heat exchanger 156 may increase the temperature of the diluted liquid desiccant 154 to enable the diluted liquid desiccant 154 to desorb a greater amount of moisture in the regenerator 144. The desiccant-desiccant heat exchanger 156 may be an in-line 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 indirect heat exchange via a vapor compression heat pump. In addition to or instead of the heat exchanger 156, auxiliary heating and cooling sources (e.g., heating and cooling fluids such as water) may be utilized to heat the diluted liquid desiccant 154 and cool the concentrated liquid desiccant 152, respectively. The liquid desiccant loop 108 may include additional or other components in addition to those shown and described with reference to Figure 1 the components shown and described.

[0034] Thus, in an example mode of operation of the HVAC system 100, sensible cooling of the first inlet air stream 110 is facilitated by the conditioner 136 of the conditioner subsystem 104, and the conditioner 136 transfers heat from the inlet air stream 110 to the conditioner heat transfer fluid. The heat removed from the first inlet air stream 110 is then sequentially transferred among the subsystems 104, 102, and 106 via the evaporator 118 and the condenser 120, and is ultimately discharged into the second inlet air stream 114 via the regenerator 144. Latent cooling of the first inlet air stream 110 is also facilitated by the conditioner 136, and the conditioner 136 removes moisture from the inlet air stream 110 using the concentrated liquid desiccant 152. The moisture absorbed by the diluted (saturated) liquid desiccant 154 is desorbed into the second inlet air stream 114 in the regenerator 144, which regenerates the concentrated liquid desiccant 152, and then the concentrated liquid desiccant 152 is directed to return toward the conditioner 136.

[0035] Figure 2is another example HVAC system 200 that includes the conditioner subsystem 102, refrigerant subsystem 104, and liquid desiccant loop 108 described above for HVAC system 100. Figure 1 and Figure 2 corresponding reference numerals in indicate corresponding parts between HVAC systems 100 and 200. HVAC system 200 also includes a regenerator subsystem 206 that is similar to the regenerator subsystem 106 of HVAC system 100. The regenerator subsystem 206 includes a regenerator 244 that facilitates the discharge of moisture from the diluted (or saturated) liquid desiccant 154 to produce the concentrated liquid desiccant 152. In this example, the regenerator subsystem 206 does not include a regenerator heat transfer fluid loop that engages with the refrigerant subsystem 102. The condenser 220 of the refrigerant subsystem 102 includes condenser coils through which a second inlet air stream 114 flows before entering the regenerator 244. The second inlet air stream 114 is heated by the condenser 220, thereby producing a heated dry air stream 116a that is then directed to the regenerator 244. The heated dry air stream 116a absorbs moisture from the saturated liquid desiccant 152 in the regenerator 244 and exits as a moist air stream 116b.

[0036] In example HVAC systems 100 and 200, heat is appropriately supplied to the regenerator 106 or 206, the second inlet air stream 114, and / or the saturated liquid desiccant 154 such that there is a vapor pressure differential between the saturated liquid desiccant in the regenerator 144 or 244 and the second inlet air stream. When the saturated liquid desiccant is heated before or within the regenerator 144 or 244, its vapor pressure rises above that of the second inlet air stream 114 or 116a, which allows moisture to transfer to the inlet air stream 114 or 116a. The illustrated HVAC systems 100 and 200 depict two example heating mechanisms for achieving the desired increase in the vapor pressure differential between the saturated liquid desiccant and the second inlet air stream in the regenerator 144 or 244. These mechanisms can also be used in combination. In other examples, any suitable additional and / or alternative devices can be used to heat the second inlet air stream 114 and / or the saturated liquid desiccant 154. For example, a heater thermally connected to the regenerator 144 or 244 (e.g., Figure 1 the heater 158 shown in), a condenser fan (e.g., Figure 2 the condenser coils 220 shown in), an in-line heater (e.g., Figure 1 and Figure 2The heat exchanger 156) shown or another auxiliary heater such as a boiler, a central hot water source, a waste heat source, and / or a hot water heater can be used to heat the second inlet air stream 114 and / or the saturated liquid desiccant 154. Any combination or sub-combination of the described heating mechanisms for increasing the vapor difference between the saturated liquid desiccant and the second inlet air stream can be implemented.

[0037] Figure 3 can be used as Figure 1 in the regenerator subsystem 106 and / or Figure 2 is a schematic view of a liquid desiccant regeneration system 300 that can be used as the regenerator subsystem 206 in . The system 300 includes a regeneration tank 302 and an air diffuser 304 that cooperate to facilitate desorbing moisture from the saturated liquid desiccant 306 contained in the regeneration tank 302 into the inlet air stream 332. The regeneration tank 302 and the air diffuser 304 can be implemented as Figure 1 the regenerator 144 in and / or Figure 2 the regenerator 244 in . Any suitable number of regeneration tanks 302 and air diffusers 304 can be included in the liquid desiccant regeneration system 300, and multiple regeneration tanks and air diffusers can be operated in series, in parallel, or in any combination of series and parallel.

[0038] The regeneration tank 302 is suitably sized and shaped for containing a volume of saturated liquid desiccant 306. The regeneration tank 302 has a tank height H1 measured between vertical ends 308, 310 (also referred to as a top end 308 and a bottom end 310). The regeneration tank 302 also has a tank width or tank diameter D1 measured perpendicular to the tank height H1 through the tank. The saturated liquid desiccant 306 is collected in (or enters) the regeneration tank 302 via a desiccant inlet 312. The desiccant inlet 312 can be defined by a desiccant inlet fitting (not shown) positioned on the regeneration tank 302 near the first top end 308. The desiccant inlet 312 is connected (e.g., via a desiccant inlet fitting) to a liquid desiccant circuit, such as Figure 1 and Figure 2 the saturated desiccant line 314 of the liquid desiccant circuit 108 in . The saturated liquid desiccant 306 can be from another air handling system operating in conjunction with the liquid desiccant regeneration system 300, such as a liquid desiccant dehumidification system (e.g., Figure 1 and Figure 2The regulator subsystem 104) in is directed to the regeneration tank 302. The regeneration tank 302 also includes a desiccant outlet 316, which can be defined by a desiccant outlet fitting (not shown) positioned on the regeneration tank near the bottom end 310. The desiccant outlet 316 is connected (e.g., via the desiccant outlet fitting) to a liquid desiccant loop, such as Figure 1 and Figure 2 the concentrated desiccant line 318 of the liquid desiccant loop 108 in. The concentrated liquid desiccant 320 that leaves the regeneration tank 302 via the desiccant outlet 316 can be directed back to the liquid desiccant dehumidification system via the concentrated desiccant line 318 (e.g., Figure 1 and Figure 2 the regulator subsystem 104) in.

[0039] In the operation of the regeneration system 300, the saturated liquid desiccant 306 contained in the regeneration tank 302 (and any concentrated liquid desiccant 320 retained in the regeneration tank before leaving via the desiccant outlet 316) defines a desiccant liquid level height H2 measured from the bottom end 310 of the tank 302. The desiccant liquid level height H2 can be shorter than the tank height H1, such that in the regeneration tank 302, an air flow gap 322 is defined between the top surface 324 of the saturated liquid desiccant 306 and the top end 308. The flow rates of the saturated liquid desiccant 306 and the concentrated liquid desiccant 320 entering and leaving the regeneration tank 302, respectively, can be controlled such that a substantially constant desiccant liquid level height H2 is maintained in the regeneration tank 302 during operation. For example, the desiccant liquid level height H2 can be maintained within a range of ±10%, ±5%, or ±1% of the average desiccant liquid level height H2.

[0040] The regeneration tank 302 also includes an air inlet 326 and an air outlet 328. The air inlet 326 can be defined by an air inlet fitting (not shown) positioned on the regeneration tank near the bottom end 310. The air outlet 328 can be defined by an air outlet fitting (not shown) positioned on the regeneration tank near the top end 308. The air inlet 326 is connected (e.g., via the air inlet fitting) to the inlet air supply line 330. The inlet air flow 332 is directed towards the regeneration tank 302 via the inlet air supply line 330 and enters the regeneration tank 302 via the air inlet 326. The inlet air flow 332 is suitably dry air capable of absorbing moisture from the saturated liquid desiccant 306 contained in the regeneration tank 302. The inlet air flow 332 can optionally be heated upstream of the air inlet 326 (e.g., using a condenser fan, an in-line heater, or another auxiliary heat source such as a boiler, a central hot water source, a waste heat source, and / or a hot water heater). As Figure 3As illustrated, a portion of the inlet air supply line 330 is suitably positioned vertically above the desiccant liquid level height H2, which can facilitate reducing or eliminating the tendency of liquid desiccant to reflux from the regeneration tank 302 into the inlet air supply line 332. The air outlet 328 is connected (e.g., via an air outlet fitting) to the outlet air line 334, and the outlet air line 334 guides the outlet air stream 336 leaving the regeneration tank 302 via the air outlet. The air outlet 328 can be positioned adjacent to the air flow gap 322 defined in the regeneration tank 302. The outlet air stream 334 has a greater humidity than the inlet air stream 332 because the outlet air stream 334 has absorbed moisture from the saturated liquid desiccant 306 contained in the regeneration tank 302, thereby producing the concentrated liquid desiccant 320.

[0041] The air diffuser 304 is positioned within the regeneration tank 302 and is immersed in the saturated liquid desiccant 306 contained in the regeneration tank 302. In other words, the air diffuser 304 is positioned in the regeneration tank 302 near the bottom end 310 and below the desiccant liquid level height H2. The air diffuser 304 is connected to the air inlet 326 and receives the inlet air stream 332 entering the regeneration tank 302. The air diffuser 304 operates to diffuse the inlet air stream 332 into a volume of the saturated liquid desiccant 306 contained in the regeneration tank 302. The diffused air stream is represented by Figure 3 the flow path 338 in. The diffused air stream 338 consists of air bubbles that are distributed throughout the volume of the saturated liquid desiccant 306 and flow vertically upward through the saturated liquid desiccant toward the air flow gap 322. The diffused air stream 338 suitably provides a large surface area in contact with the saturated liquid desiccant 306, which facilitates optimizing the amount of moisture absorbed from the saturated liquid desiccant. The diffused air stream 338 flows through the surface 324 of a volume of the saturated liquid desiccant, thereby forming the outlet air stream 336 in the air flow gap 322, and the outlet air stream 336 then leaves the regeneration tank 302 via the air outlet 328.

[0042] Also referring to Figure 4 and Figure 5 , the air diffuser 302 has a diffuser body 340, which is suitably sized and shaped for positioning in the regeneration tank 302. In the Figure 3 example of, the regeneration tank 302 has a circular cross-section defining a diameter D1. In this example, the diffuser body 340 has an annular shape, which has opposing radial surfaces 342, 344 and a circumferential edge 346 extending between the radial surfaces 342, 344. The circumferential edge 346 defines the outer diameter D2 of the diffuser body 340 ( Figure 4), the outer diameter D2 is less than or substantially equal to the diameter D1. The outer diameter D2 of the diffuser body 340 can be such that the diffuser body is positioned and held in the regeneration tank 302 by a press fit between the inner wall of the regeneration tank 302 and the circumferential edge 346 of the diffuser body 340. In other examples, the diffuser body 340 can be held in the regeneration tank 302 by any suitable means. The size and shape of the diffuser body 340 can vary according to the size and shape of the regeneration tank 302.

[0043] The diffuser body 340 includes an internal volume that defines an air passage (represented by the flow path 348 in Figure 3 ) for circulating the inlet air stream 332. Air flow openings 352 can be defined in the diffuser body 340, for example, in the circumferential edge 346 (as shown in Figure 4 ) and / or on one of the radial surfaces 342, 344. The air flow openings 352 can be directly or indirectly connected to the air inlet 326 of the regeneration tank 302 and allow the inlet air stream 332 to enter the air passage 348.

[0044] The air diffuser 304 further includes an outlet port 350 defined in the diffuser body 340. The outlet port 350 is sized, shaped, and positioned to diffuse the inlet air stream 332 that circulates through the air passage 348 into the saturated liquid desiccant 306, thereby generating a diffused air stream 338. The outlet port 350 can be a series of small holes positioned on the radial surface 342 facing the top end 308 of the regeneration tank 302. The outlet port 350 can have any suitable arrangement to facilitate diffusing (distributing) the diffused air stream 338 in the saturated liquid desiccant 306. For example, the outlet port 350 can be arranged in a circular pattern ( Figure 3 and Figure 4 ) or a spiral pattern ( Figure 5 ) on the radial surface 342. In some examples, the outlet port 350 can additionally and / or alternatively be located on the circumferential edge 346 and / or on the radial surface 344 facing the bottom end 310 of the regeneration tank 302. The outlet ports 350 can each have the same shape and / or size, or the shape and / or size of the outlet ports 350 can vary. For example, the outlet ports 350 can have the same cross-sectional size and / or shape, or the outlet ports 350 can have different cross-sectional sizes and / or shapes. Additionally and / or alternatively, the outlet ports 350 can have the same or different geometries. The outlet port 350 can have any suitable geometry, such as for example prismatic (e.g., cylindrical), bell-shaped, conical, parabolic, and other shapes.

[0045] The outlet port 350 can be sized, shaped, and positioned to control (e.g., generate) turbulence in the diffused air stream 338. The turbulence can enhance the contact and moisture transfer between the diffused air stream 338 and the saturated liquid desiccant 306. For example, the outlet port 350 can be formed at an angle in the radial surface 342 such that the diffused air stream 338 has a controlled flow path in the saturated liquid desiccant 306 for generating turbulence. The outlet port 350 can be oriented at a similar angle to generate a series of coordinated flow paths (e.g., multiple helical flow paths) of the diffused air stream 338. Alternatively, the outlet port 350 can be oriented at different angles to generate a chaotic flow path of the diffused air stream 338. Additionally and / or alternatively, one outlet port, some outlet ports, or all of the outlet ports 350 can include nozzles that control the entry angle from the respective outlet port 350 for controlling the flow path of the diffused air stream 338. Other mechanisms can be additionally and / or alternatively used, such as generating turbulence in the diffused air stream 338 by rotating the air diffuser 304 within the regeneration tank 302 and / or using mixing elements (e.g., impellers or baffles) in the regeneration tank 302.

[0046] The diffuser body 340 is positioned in the regenerator tank 302 between the desiccant inlet 312 and the desiccant outlet 316 and defines a desiccant flow path (represented by the flow route 354 in Figure 3 ). The saturated liquid desiccant 306, from which water has been desorbed into the diffused air stream 338 to produce the concentrated liquid desiccant 320, flows through the desiccant flow path 354 toward the desiccant outlet 316. In the illustrated example, the saturated liquid desiccant 306 flows vertically downward in the regeneration tank 302, countercurrent or opposite to the diffused air stream 338 that flows vertically upward toward the air flow gap 322, and the concentrated liquid desiccant 320 continues to flow vertically downward through the desiccant flow path 354. In the Figures 3 to 5 example shown, the diffuser body 340 includes a central passage 356 that extends through the radial surfaces 342, 344, and the central passage 356 forms the desiccant flow path 354. The outlet ports 350 can be in a circular pattern ( Figure 3 and Figure 4 ) or a helical pattern ([[]] Figure 5 ) around the central passage 356 on the radial surface 342. In other examples, the diffuser body 340 can additionally and / or alternatively include multiple passages that form separate portions of the desiccant flow path 354. For example, in addition to or instead of the central passage 356, the diffuser body 340 can include passages that are positioned radially outward (e.g., near the circumferential edge 346) and that form separate portions of the desiccant flow path 354.

[0047] Figure 6 is an alternative example of an air diffuser 304, in which the air diffuser 304 includes a plurality of (e.g., three) body portions 340a to 340c. In this example, any number of body portions may be included, such as two body portions or more than two body portions. Each body portion 340a to 340c may have the same configuration as described above with reference to Figures 3 to 5 The diffuser body 340 is similarly configured as described above. Figures 3 to 5 The reference numerals used for the diffuser body 340 correspond to Figure 6 The reference numerals for each body portion 340a to 340c in the figure indicate corresponding parts. The body portions 340a to 340c are similarly shaped and gradually reduced in size so that the air diffuser 304 has a tapered width or diameter. In the illustrated example, as with the diffuser body 340, each body portion 340a to 340c is annular in shape and includes radial surfaces 342a to 342c, 344a to 344c, circumferential edges 346a to 346c and central passages 356a to 356c. The body portions 340a to 340c can be axially aligned along the central passages 356a to 356c. The body portions 340a to 340c are also axially spaced apart so that gaps are defined between adjacent body portions 340a to 340c, thereby providing radial passages leading to the axially aligned central passages 356a to 356c.

[0048] The size (diameter) of the first body portion 340a, which may also be referred to as the bottom body portion 340a, is the largest. When the body portions 340a to 340c are positioned in the regeneration tank 302, the bottom body portion 340a is positioned close to the bottom end 310. The size (diameter) of the body portions 340b and 340c decreases in sequence so that when positioned in the regeneration tank 302, the size (diameter) of the air diffuser 304 tapers toward the top end 308. The radial surface 342a of the bottom body portion 340a extends radially outward beyond the circumferential edge 346b of the second or "middle" body portion 340b. The radial surface 342b of the middle body portion 340b extends radially outward beyond the circumferential edge 346a of the third or "top" body portion 346a.

[0049] The spaced apart body portions 340a-340c may be connected to define a single air passage 348 ( Figure 3 ), as described above for diffuser body 340. For example, adjacent body portions 340a-340c may be fluidly connected by conduits or pipes (not shown) extending between body portions 340a-340c.Figure 6 As shown in , there may be a single air flow opening 352 on the circumferential edge 346a), and the inlet air flow 332 can enter the air passage 348 through the single air flow opening 352 and circulate through each of the body portions 340a to 340c. In other examples, the body portions 340a to 340c may be fluidly isolated from each other, and each body portion may include a separate air flow opening for receiving a portion of the inlet air flow 332.

[0050] Each of the body portions 340a to 340c includes outlet ports 350a to 350c, which are sized, shaped, and positioned to diffuse the inlet air flow 332 that has circulated through the air passage 348 into the saturated liquid desiccant 306, thereby generating a diffused air flow 338. The outlet ports 350a to 350c are located on the radial surfaces 342a to 342c of the respective body portions 340a to 340c. In some examples, one, some, or all of the body portions 340a to 340c may include outlet ports 350a to 350c located on the radial surfaces 344a to 344c and / or the circumferential edges 346a to 346c. The outlet ports 350a to 350c may have any suitable size, shape, and / or arrangement on the respective body portions 340a to 340c, including the size, shape, and / or arrangement described above for the outlet port 350 of the diffuser body 340. The outlet ports 350a to 350c may be sized, shaped, and positioned to control (e.g., generate) turbulence in the diffused air flow 338, as described above for the outlet port 350. Any of the above descriptions of the outlet port 350 apply to the outlet ports 350a to 350c of the body portions 340a to 340c and may be implemented in the outlet ports 350a to 350c of the body portions 340a to 340c. In some examples, the outlet port 350a on the bottom body portion 340a may be positioned on the radial surface 342a at a position radially beyond the circumferential edge 346b of the middle body portion 340b. Similarly, the outlet port 350b on the middle body portion 340b may be positioned on the radial surface 342b at a position radially beyond the circumferential edge 346c of the top body portion 340c.

[0051] When Figure 6When the air diffuser 304 shown in [Figure] is operating within the regeneration tank 302, the body portions 340a - 340c cooperate to define a tortuous desiccant flow path for the saturated liquid desiccant 306, which has desorbed water into the diffused air stream 338 and flows as concentrated liquid desiccant 320 toward the desiccant outlet 316. In particular, the liquid desiccant 306 / 320 flows through both a portion of the desiccant flow path formed by the axially - aligned central passages 356a - 356c and a radially - outer portion of the desiccant flow path formed around the circumferential edges of the top body portion 340c and the intermediate body portion 340b. Then, the radially - outward flowing liquid desiccant 306 / 320 flows through the gaps defined between adjacent, spaced - apart body portions 340a, 340b and 340b, 340c to converge with the liquid desiccant flowing through the axially - aligned central passages 356a - 356c. This tortuous desiccant flow path can promote greater turbulence and better mixing of the saturated liquid desiccant 306 and the diffused air stream 338. The multiple body portions 340a - 340c can also promote increased turbulence in the diffused air stream and / or a greater distribution of the diffused air stream by increasing the number of outlet ports 350a - 350c and / or providing more variations in the spatial relationship of the outlet ports 350a - 350c within the regeneration tank 302.

[0052] Referring again to Figure 3 , the liquid desiccant regeneration system 300 can include one or more heaters 358, 360, 362 that are operable to increase the vapor pressure differential between the saturated liquid desiccant 306 and the inlet air stream 332. The heaters 358, 360, 362 can be any suitable heat source, such as for example any one or more of a condenser fan or coil, a hot fluid exiting a condenser, an in - line heater, a boiler, a central hot water source, a waste heat source, and a hot water heater, or can be connected to any suitable heat source, such as for example any one or more of a condenser fan or coil, a hot fluid exiting a condenser, an in - line heater, a boiler, a central hot water source, a waste heat source, and a hot water heater. Any combination or sub - combination of the exemplary heaters 358 - 362 can be implemented.

[0053] A first exemplary heater 358 that may be included in system 300 is thermally connected to the regeneration tank 302. The first heater 358 is operative to heat the saturated liquid desiccant 306 within the regeneration tank 302, thereby increasing the vapor pressure of the saturated liquid desiccant and facilitating greater moisture desorption into the diffused air stream 338. The first heater 358 may include a heating coil located within the regeneration tank 302 and / or a heating jacket surrounding the regeneration tank 302. The first heater 358 may circulate a hot fluid (e.g., hot water or a hot heat transfer fluid) for heating the saturated liquid desiccant 306. In some examples, the first heater 358 may be connected to the regenerator heat transfer loop 146 ( Figure 1 shown therein), and circulate the heated regenerator heat transfer fluid 148 exiting the condenser 120, as described above for heater 158.

[0054] A second exemplary heater 360 that may be included in system 300 is thermally connected to the inlet air supply line 330. The second heater 360 is operative to heat the inlet air stream 332 before the inlet air stream enters the regeneration tank 302. The heated inlet air stream 332 may transfer heat to the saturated liquid desiccant 306 within the regeneration tank 302, thereby increasing the vapor pressure of the saturated liquid desiccant and facilitating greater moisture desorption into the diffused air stream 338. In some examples, the second heater 360 may include Figure 2 the condenser coil 220 shown therein, which may produce a heated dry air stream that is then directed to the regeneration tank 302 as described above. The second heater 360 may additionally and / or alternatively include an in-line heat exchanger or any suitable heat exchanger or auxiliary heating source that facilitates heating the inlet air stream 332 upstream of the regeneration tank 302.

[0055] A third exemplary heater 362 that may be included in system 300 is thermally connected to the saturated desiccant line 314. The third heater 362 is operative to heat the saturated liquid desiccant upstream of the regeneration tank 302, thereby increasing the vapor pressure of the saturated liquid desiccant and facilitating greater moisture desorption into the diffused air stream 338. In some examples, the third heater 362 may include a desiccant-desiccant heat exchanger (e.g., Figure 1 and Figure 2The heat exchanger 156) shown in [reference], this desiccant-desiccant heat exchanger facilitates the transfer of heat from the concentrated liquid desiccant 320 leaving the regeneration tank 302 to the saturated liquid desiccant 306 entering the regeneration tank 302. The third heater 362 can additionally and / or alternatively include an in-line heat exchanger, any suitable heat exchanger that promotes direct or indirect heat transfer between the concentrated liquid desiccant 320 and the saturated liquid desiccant 306, and / or another auxiliary heat source such as those auxiliary heat sources described above.

[0056] Figure 7 is an example method 400 for operating a liquid desiccant regeneration system, such as Figure 3 the liquid desiccant regeneration system 300 shown in [reference]. Method 400 includes collecting 402 the saturated liquid desiccant 306 in the regeneration tank 302. The saturated liquid desiccant 306 can be collected 402 in the regeneration tank 302 by the following method: guiding the saturated liquid desiccant via the saturated desiccant pipeline 314 from another air handling system operating in conjunction with the liquid desiccant regeneration system 300, such as a liquid desiccant dehumidification system (e.g., Figure 1 and Figure 2 the regulator subsystem 104 in [reference]) to the regeneration tank. Method 400 further includes supplying 404 an air stream (e.g., the inlet air stream 332) to the air diffuser 304 positioned in the regeneration tank 302. Method 400 can include heating the air stream 332 and / or the saturated liquid desiccant 306 upstream of and / or within the regeneration tank 302, such that the vapor pressure difference between the saturated liquid desiccant and the air stream increases to facilitate the desorption of moisture from the saturated liquid desiccant into the air stream. The air stream 332 and / or the saturated liquid desiccant 306 can optionally be heated using one or more heaters (e.g., Figure 3 the heaters 358, 360, 362 in [reference]). Method 400 further includes diffusing 406 the air stream 332 into the saturated liquid desiccant 306 collected 402 in the regeneration tank 302, such that the diffused air stream 338 absorbs moisture from the saturated liquid desiccant 306. Diffusing the air stream 332 into the saturated liquid desiccant 306 can include generating turbulence in the diffused air stream 338 using the air diffuser 304. Method 400 can further include guiding the concentrated liquid desiccant 320 through the passage 356 defined by the air diffuser 304 towards the desiccant outlet 316 of the regeneration tank 302. Method 400 can further include guiding the concentrated liquid desiccant 320 leaving the regeneration tank 302 via the desiccant outlet 316 back to the liquid desiccant dehumidification system (e.g., Figure 1 and Figure 2 the regulator subsystem 104 in [reference]).

[0057] The described example HVAC system includes a liquid desiccant regeneration system that is configured to transfer moisture from a saturated liquid desiccant to an air stream to produce a concentrated liquid desiccant, which can be redirected to a dehumidification system. The liquid desiccant regeneration system includes one or more regeneration tanks for collecting the saturated liquid desiccant and an air diffuser positioned within each regeneration tank. The air diffuser is operative to diffuse an air stream into the saturated liquid desiccant. The diffused air stream comprises air bubbles that are distributed throughout the volume of the saturated liquid desiccant and flow through the saturated liquid desiccant, thereby providing a large surface area contact between the air stream and the saturated liquid desiccant. This helps to optimize the amount of moisture absorbed from the saturated liquid desiccant. The air diffuser may also create turbulence in the diffused air stream, further enhancing moisture transfer. The liquid desiccant regeneration system may also include one or more heaters that are operative to increase the vapor pressure of the saturated liquid desiccant and facilitate greater desorption of moisture into the diffused air stream. The liquid desiccant regeneration system can help to reduce the size and overall footprint of a liquid desiccant regenerator and may also reduce manufacturing costs, installation costs, and / or operating costs. The liquid desiccant regeneration system may also facilitate regeneration of the liquid desiccant during off-peak hours of the HVAC system, thereby reducing energy costs and increasing system efficiency.

[0058] Example embodiments of an HVAC system and a method of operating the system have been described in detail above. The system and method are not limited to the specific embodiments described herein. Instead, components of the system and method can be used independently and separately from other components described herein. For example, the system described herein can be used in systems other than an HVAC system.

[0059] When introducing elements of the present disclosure or embodiments thereof, the articles “a,” “an,” “the,” and “said” are intended to mean that there is one or more of the elements. The terms “comprising,” “including,” “having,” and “containing” 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 items described.

[0060] The terms “about,” “substantially,” “essentially,” and “approximately” and their equivalents, when used in connection with a range of dimensions, concentrations, temperatures, or other physical or chemical properties or characteristics, mean to encompass variations that may exist in the upper and / or lower limits of the range of the property or characteristic, including, for example, variations resulting from rounding, measurement methods, or other statistical variations.

[0061] Since various changes can be made to the above-described configurations and methods without departing from the scope of the present disclosure, all of the content included in the above description and shown in the accompanying drawings should be construed as illustrative and not in a limiting sense.

Claims

1. A liquid desiccant regeneration system, the liquid desiccant regeneration system comprising: A regeneration tank for containing saturated liquid desiccant, the regeneration tank having an air inlet, a desiccant inlet, and a desiccant outlet; And An air diffuser positioned within the regeneration tank between the desiccant inlet and the desiccant outlet, wherein the air diffuser is operable to receive an air stream from the air inlet and diffuse the air stream into the saturated liquid desiccant contained within the regeneration tank.

2. The liquid desiccant regeneration system according to claim 1, wherein, The air diffuser has a diffuser body and an outlet port, the diffuser body defining an air passage for circulating the air stream received from the air inlet, the outlet port being defined in the diffuser body to diffuse the air stream into the saturated liquid desiccant.

3. The liquid desiccant regeneration system according to claim 2, wherein, The outlet port is sized, shaped, and positioned such that the air diffuser is operable to create turbulence in the air stream diffused into the saturated liquid desiccant.

4. The liquid desiccant regeneration system according to claim 2, wherein, The diffuser body has an annular shape.

5. The liquid desiccant regeneration system according to claim 4, wherein, The diffuser body defines a passageway that forms a desiccant flow path between the desiccant inlet and the desiccant outlet.

6. The liquid desiccant regeneration system according to claim 5, wherein, The outlet port defined in the diffuser body is in one of a circular pattern and a spiral pattern around the passageway.

7. The liquid desiccant regeneration system according to claim 2, wherein, The diffuser body includes a plurality of body parts that cooperate to define a tortuous desiccant flow path between the desiccant inlet and the desiccant outlet.

8. The liquid desiccant regeneration system according to claim 1, wherein, The regeneration tank has an air outlet vertically above the air inlet, wherein the air diffuser is positioned between the air inlet and the air outlet.

9. A heating, ventilation, and air conditioning system, the heating, ventilation, and air conditioning system comprising: A dehumidification subsystem operable to transfer moisture between a liquid desiccant and a first air stream; And A regeneration subsystem operable to transfer moisture between the liquid desiccant and a second air stream, wherein the heating, ventilation, and air conditioning system is operable to circulate the concentrated liquid desiccant to the dehumidification subsystem and circulate the saturated liquid desiccant to the regeneration subsystem, wherein the regeneration subsystem includes: A regeneration tank for containing the saturated liquid desiccant, the regeneration tank having an air inlet, a desiccant inlet, and a desiccant outlet; and An air diffuser positioned within the regeneration tank between the desiccant inlet and the desiccant outlet, wherein the air diffuser is operable to receive the second air stream from the air inlet and diffuse the second air stream into the saturated liquid desiccant contained within the regeneration tank.

10. The heating, ventilation and air conditioning system according to claim 9, wherein, The heating, ventilation, and air conditioning system is operable to increase the vapor pressure difference between the saturated liquid desiccant and the second air stream.

11. The heating, ventilation, and air conditioning system according to claim 10 further includes a heater that is operable to increase the vapor pressure difference between the saturated liquid desiccant and the second air stream.

12. The heating, ventilation and air conditioning system according to claim 11, wherein, The heater includes at least one of a heating coil, a heating jacket, a condenser fan, an inline heater, a boiler, a central hot water source, a waste heat source, and a hot water heater.

13. The heating, ventilation and air conditioning system according to claim 11, wherein, The heater is thermally connected to the regeneration tank to heat the saturated liquid desiccant within the regeneration tank.

14. The heating, ventilation, and air conditioning system according to claim 9, wherein, The air diffuser has a diffuser body and an outlet port. The diffuser body defines an air passage for circulating the second air stream received from the air inlet, and the outlet port is defined in the diffuser body to diffuse the second air stream into the saturated liquid desiccant contained in the regeneration tank.

15. The heating, ventilation and air conditioning system according to claim 14, wherein, The outlet port is sized, shaped, and positioned such that the air diffuser is operable to create turbulence in the second air stream diffused into the saturated liquid desiccant.

16. The heating, ventilation, and air conditioning system according to claim 14, wherein, The diffuser body defines a passage that forms a desiccant flow path between the desiccant inlet and the desiccant outlet.

17. A method of operating a liquid desiccant regeneration system, the method comprising: Collecting saturated liquid desiccant in a regeneration tank; Supplying an air stream to an air diffuser positioned within the regeneration tank; And Using the air diffuser to diffuse the air stream into the saturated liquid desiccant collected in the regeneration tank such that the diffused air stream absorbs moisture from the saturated liquid desiccant.

18. The method according to claim 17 further includes heating at least one of the air stream supplied to the air diffuser and the saturated liquid desiccant collected in the regeneration tank to increase the vapor pressure difference between the saturated liquid desiccant and the air stream.

19. The method according to claim 17, wherein Diffusing the air stream into the saturated liquid desiccant includes using the air diffuser to create turbulence in the air stream diffused into the saturated liquid desiccant.

20. The method according to claim 17 further includes guiding the concentrated liquid desiccant toward the desiccant outlet of the regeneration tank through the passage defined by the air diffuser.

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