Atmospheric water generating system including hygroscopic medium and method of use thereof

Abstract

The atmospheric water generating system includes an absorption chamber configured to facilitate absorption or adsorption of water from the atmosphere or ambient air into and / or onto a hygroscopic medium, and a separation vessel in fluid communication with the absorption chamber for extracting the absorbed or adsorbed water from the hygroscopic medium. This disclosure describes methods for producing purified water using atmospheric water generating systems, and methods for producing water from moisture-laden gases.

Description

[Technical Field]

[0001] Related Applications This patent application claims the benefit of priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 63 / 442,350, filed January 31, 2023, which is incorporated herein by reference in its entirety.

[0002] FIELD OF THE DISCLOSURE The present disclosure relates generally to atmospheric water generation, and more particularly to systems and methods for atmospheric water generation utilizing hygroscopic media. [Background technology]

[0003] Standard atmospheric water generation (AWG) systems face various challenges, including the high energy demands associated with multiple water phase changes to produce a unit of water. First, water vapor is extracted from the air and entrained in an intermediate fluid, typically a liquid desiccant. The water vapor then undergoes another highly energy-intensive process before being extracted as liquid water from the intermediate fluid. Other systems use direct cooling to cool the water vapor to its dew point and extract it as liquid water on a cooled surface. Summary of the Invention

[0004] Although multiple attempts have been made to reduce the overall energy consumption of AWG systems, energy reduction techniques are still limited by their feasibility in AWG operation under all weather conditions. Therefore, alternative and innovative technologies that produce water in an energy-efficient manner are required. [Brief explanation of the drawings]

[0005] [Figure 1] Figure 1 shows a list of component ions that may represent hygroscopic media. [Figure 2] FIG. 2 is a schematic diagram of an example atmospheric water generation (AWG) system illustrating the AWG process. [Figure 3A]Figure 3A illustrates the behavior of hygroscopic media and water. At temperatures below the lower critical solution temperature (LCST), the hygroscopic media dissolve in water to form a homogeneous solution (Figure 3A). When heated above the LCST, the homogeneous solution separates into a hygroscopic media phase (bottom of the vial) containing the hygroscopic media and an aqueous phase (top of the vial) containing the trapped water; the aqueous and hygroscopic media phases are immiscible (Figure 3B). Upon cooling, a single homogeneous phase forms again (Figure 3A). [Figure 3B] Figure 3B illustrates the behavior of hygroscopic media and water. At temperatures below the lower critical solution temperature (LCST), the hygroscopic media dissolve in water to form a homogeneous solution (Figure 3A). When heated above the LCST, the homogeneous solution separates into a hygroscopic media phase (bottom of the vial) containing the hygroscopic media and an aqueous phase (top of the vial) containing the trapped water; the aqueous and hygroscopic media phases are immiscible (Figure 3B). Upon cooling, a single homogeneous phase forms again (Figure 3A). [Figure 4A] FIG. 4A is a schematic diagram showing a top view of multiple separators (configured as a centrifugation unit) performing centrifugation. [Figure 4B] FIG. 4B is a schematic diagram showing a cross section of one type of centrifuge device that can be used as an alternative to a settling tank to separate the hygroscopic media from the captured water. [Figure 5] FIG. 5 is a schematic diagram showing a cross section of a separation device configured for pressure-driven membrane separation. [Figure 6A] FIG. 6A is a schematic diagram illustrating an exemplary configuration of an AWG system. [Figure 6B] FIG. 6B is a schematic diagram illustrating an exemplary configuration of an AWG system. DETAILED DESCRIPTION OF THE INVENTION

[0006] This disclosure describes a hygroscopic medium that can absorb moisture from the air in a first stage and then desorb or release the moisture in a second stage with minimal energy input, along with an AWG system that utilizes this hygroscopic medium. In summary, the primary objective is to use little or no energy to extract moisture from the hygroscopic medium. Recent research has focused on removing moisture from the hygroscopic medium so that the medium can be recycled in a moisture recovery process. Otherwise, the hygroscopic medium used to absorb moisture cannot be reused in a closed-loop system. Closed-loop systems have the potential to reduce costs, waste, and prevent environmental harm from fluid loss.

[0007] Compositions described below that adsorb or absorb water and respond to an energy input or mixing with a gas can be referred to as hygroscopic media. Compositions that respond to an energy input, particularly an input such as thermal energy, can be referred to as hygroscopic thermally responsive media. Compositions that respond to mixing with a specific gas can be referred to as hygroscopic gas-responsive media. In this disclosure, the terms "hygroscopic media," "hygroscopic fluid," "hygroscopic fluid media," and "media" can be used interchangeably to refer to these compositions.

[0008] When used in an AWG system, the energy input or output to a hygroscopic thermally responsive medium is thermal energy (heating or cooling the thermally responsive medium) to increase or decrease the temperature of the medium. In certain embodiments, two different categories of thermally responsive medium can be used: upper critical solution temperature (UCST) media and lower critical solution temperature (LCST) media. The critical solution temperature is the pressure and temperature combination above and below which the solution is no longer in a two-phase liquid state. For USCT media, increasing the temperature above the critical solution temperature can cause the medium to form a homogeneous liquid phase. Reducing the temperature below the critical solution temperature can result in two-phase liquid-liquid separation, where the two phases are in equilibrium with each other. For LCST media, reducing the temperature below the critical solution temperature can result in a homogeneous liquid phase. Furthermore, increasing the temperature above the critical solution temperature can result in two-phase liquid-liquid separation due to the negative entropy of mixing. The hygroscopic thermoresponsive medium employed in this disclosure exhibits liquid-liquid phase separation when heated above the LCST due to the negative entropy of mixing. The energy required to separate water from the medium (i.e., the enthalpy of mixing) is approximately 10 J / g, three orders of magnitude less than the energy required for the first-order phase transition of water (2400 J / g) common in traditional thermal regeneration. Furthermore, near-zero-energy separation of water from the hygroscopic thermoresponsive medium requires only a small input of energy in the form of sensible heat (similar to the heat felt when warming a sample glass vial in the palm of your hand) to reach temperatures above the LCST, which can be combined with low-grade energy sources such as solar thermal energy. Once the energy change results in a two-phase liquid-liquid solution, the desired phase can be extracted for use or further processed for purification.

[0009] One promising approach to extracting moisture from liquid desiccants is to utilize LCST phase separation. Separating a homogeneous hygroscopic aqueous solution into its constituent liquids by sensible heating eliminates the need for evaporation / distillation and the associated latent heat of phase change. This potentially enables more energy-efficient alternative cycles for many applications, such as atmospheric water recovery, which involve the separation of miscible liquids during regeneration for water recovery. The LCST phase behavior of hygroscopic thermoresponsive media is advantageous and can typically be controlled by appropriate selection of concentration, temperature, cations, anions, and solvents. Homogeneous hygroscopic thermoresponsive media can be phase-separated by applying a minimal temperature gradient to separate water from the media with nearly zero energy.

[0010] Selecting an appropriate hygroscopic medium based on the overall system design can minimize energy and capital investment, suggesting the need for the development of an AWG framework that optimizes multiple material properties. To this end, it is beneficial to measure the properties of hygroscopic medium-water mixtures as a function of concentration and temperature and to understand their mechanisms. These thermally and / or gas-responsive hygroscopic media can be used in AWG systems and methods. In some examples, hygroscopic media can include ionic liquids, polymers, organic solvents, and / or salt water. Figure 1 shows a list of component ions that may represent hygroscopic media. Components of the hygroscopic medium can include, for example, in some embodiments, tetrabutylphosphonium bromide, tetrabutylphosphonium chloride, tetrabutylphosphonium trifluoroacetate, tributyl(octyl)phosphonium bromide, poly(N-isopropylacrylamide), 1-hexyl-3-methylimidazolium bromide, tributylhexylphosphonium bromide, a double salt of 1,3-dimethylimidazolium iodide and tetrabutylphosphonium 2,4-dimethylbenzenesulfonate, tetrabutylphosphonium trifluoroacetate, tetrabutylphosphonium mesitylenesulfonate, tributyloctylphosphonium bromide, tetrabutylphosphonium p-toluenesulfonate, tetrabutylphosphonium N-trifluoromethanesulfonylleucine salt, and / or mixtures thereof. In certain embodiments, the hygroscopic fluid can include [N 4444 ][TMBS], [N 4444 ]CF3COO,[P 4444 ][Sal], [P 4444 ][SS], [N 4444 ]CF3COO,[P 4444 [Mal], and / or mixtures thereof. In certain embodiments, the hygroscopic media incorporated herein can include other materials, including but not limited to colloids, nanomaterials, and / or combinations thereof, to enhance process efficiency.

[0011] FIG. 2 is a schematic diagram illustrating an example atmospheric water generation system, illustrating the AWG process. Various embodiments relate to an AWG system 100 that utilizes a hygroscopic medium 104 to absorb water 130 from air (e.g., absorb water vapor in atmospheric air 132) and make the absorbed water 130 available as clean liquid water. Specifically, certain embodiments are directed to any of a variety of liquid-liquid extraction processes that utilize heating and / or cooling of the hygroscopic medium 104 (by separating the hygroscopic medium 104 from the water 130 that dilutes the hygroscopic medium) to facilitate water absorption (e.g., in the absorber or absorption chamber 102) and water extraction. The dried air 134 then returns from the absorber 102 to the atmosphere. In certain embodiments, certain gases are extracted from the air (e.g., after removing water vapor from the air) in a gas extraction stage 118. In certain embodiments, the captured dry air 134 can be passed through a carbon capture module in the gas extraction stage 118 before discharging the dried and dehumidified air 134 into the surrounding environment, thereby establishing a negative carbon footprint towards the development of a sustainable and circular economy.

[0012] One embodiment includes an absorption loop that passes atmospheric or ambient air 132 through an absorption chamber 102 configured to promote the absorption or adsorption of water 130 into the hygroscopic medium 104. In some embodiments, the hygroscopic medium 104 entering the absorber 102 may have a content of approximately 5% to 95% by weight. Bulk mass transfer of water 130 from the ambient air 132 by absorption and / or adsorption mechanisms is driven by the difference in vapor pressure between the water 130 (water vapor) in the air 132 and the hygroscopic medium 104. Two-phase liquid-liquid separation or extraction may occur in response to energy inputs (i.e., energy input or output to the medium 104), such as heat, electricity, or kinetic energy, and / or energy changes, such as the input and mixing of certain gases into the hygroscopic medium 104.

[0013] When water vapor 130 from the air 132 is absorbed or adsorbed into the hygroscopic medium 104, what is referred to herein as a lean hygroscopic medium 116 or a water-containing hygroscopic medium 116 is formed. The lean hygroscopic medium 116 can be heated before, during, or after entering the separator 106 (e.g., settling tank 124). For example, the lean hygroscopic medium 116 can be heated in the energy exchange device 120 to a temperature above the LCST of the medium, which may be concentration-dependent. When the lean hygroscopic medium 116 is heated above the LCST, the fluid phase separates into the hygroscopic medium 104 and the entrapped water 130. In some embodiments, the lean hygroscopic medium is heated to a temperature less than about 90°C. In some embodiments, the LCST of the hygroscopic medium can be at least about 25°C or less, at least about 30°C or less, or at least about 45°C or less. In certain embodiments, direct sunlight can be used, which can heat the dilute hygroscopic medium to temperatures of about 45° C. or higher, while concentrated sunlight can be used to raise the desired temperature until the LCST of the dilute hygroscopic medium is reached, which in some cases can be as high as 75° C.

[0014] In the settling tank 124, the water-rich phase 130 is completely or partially separated from the hygroscopic medium phase 104 and can be immediately stored or used. After phase separation of the hygroscopic medium 104 diluted with the capture water 130 in the absorber, the hygroscopic medium 104 may be physically separated from the capture water 130. In some embodiments, the settling tank 124 facilitates the physical separation of the hygroscopic medium 104 and the capture water 130. For example, in some embodiments, the density of the hygroscopic medium 104 above the LCST is higher than the density of the captured water 130. When the dilute hygroscopic medium 116 phase separates, the captured water 130 may reside separated above or below the hygroscopic medium 104. When the dilute hygroscopic medium 116 phase separates in this manner, the captured water 130 may be discharged or removed from the top or bottom of the separator 106. The captured water 130 may contain small amounts of residual hygroscopic medium 104, which can be removed using downstream secondary unit operations 122, including, but not limited to, centrifugation and / or membrane filtration. The rich hygroscopic medium 104 can, in certain embodiments, be passed back through the absorption chamber 102 in a closed loop to absorb and / or adsorb more water 130. The hygroscopic medium 104, or a mixture of hygroscopic medium and water (e.g., dilute hygroscopic medium 116), can have a low viscosity so that it can be easily pumped through the piping of an AWG system 100 operable to perform the methods described herein. By way of example, the hygroscopic medium and water mixture may have a viscosity of less than 500 millipascal-seconds (mPa·s), or in the range of about 1 mPa·s to about 30 mPa·s, or up to about 50 mPa·s, under the operational conditions of the AWG system.

[0015] As an example, a homogeneous hygroscopic thermoresponsive medium of a given concentration undergoes phase separation by increasing the solution temperature. Notably, this phase separation results in immiscible liquid phases without evaporation or the consumption of latent energy. An example of such a thermoresponsive two-phase system consisting of a hygroscopic thermoresponsive medium 104 and water 130 is depicted in Figures 3A and 3B, where phase separation is achieved with a temperature swing of approximately 10–15°C without evaporating water. At temperatures below the LCST, the hygroscopic thermoresponsive medium dissolves in water, forming a homogeneous solution or dilute hygroscopic medium 116 (Figure 3A). Upon heating to temperatures above the LCST, the homogeneous solution initially becomes cloudy and then separates into a hygroscopic thermoresponsive medium phase 104 at the bottom of the vial and an immiscible water phase 130 at the top (Figure 3B). After cooling, a single homogeneous phase or dilute hygroscopic medium 116 re-forms (Figure 3A). This demonstrates the phenomenon where the presence of water destabilizes the thermodynamic equilibrium of the separated phases, and the positive contribution of water's excess Gibbs energy decreases as temperature increases. Here, water-hygroscopic medium interactions prevail over water-water and hygroscopic medium-hygroscopic medium interactions, leading to phase homogenization. To more clearly visualize the phase separation, Coomassie Brilliant Blue R-250 may be added to the solution. This temperature-induced mixing-demixing is completely reversible, allowing a hygroscopic thermoresponsive medium to be recycled in a closed-loop system for efficient water generation, a feat not previously described for atmospheric water generation applications.

[0016] In certain embodiments, the two-phase liquid can be separated via centrifugation to separate the hygroscopic medium 104 from the captured water 130, as shown in FIG. 4 . The separator or extraction unit 106 can include a centrifuge unit 126, which may be referred to as a centrifuge-driven liquid-liquid extractor 126, in which the lean hygroscopic liquid medium 116 can be centrifuged at a desired rpm (revolutions per minute). By way of example, the rpm can be set to provide an acceleration of 17,000 g or less. In certain embodiments, the centrifugation time can be varied. In certain embodiments, the separation unit 106 is configured to operate in batch or continuous mode to fit the overall AWG system configuration. Centrifugation can be performed at a temperature above the LCST, thereby phase-separating the lean hygroscopic medium 116 into the hygroscopic medium 104 and the captured water 130. In some embodiments, the density of the hygroscopic medium 104 above the LCST is greater than the density of the captured water 130. When the dilute hygroscopic medium 116 phase separates, the captured water 130 floats on top (or below, depending on density) of the hygroscopic medium 104. Once the dilute hygroscopic medium 116 has phase-separated in this manner, the captured water 130 can be poured or removed from the top of the container 106, 126. In some embodiments, a porous membrane 128 with hydrophilic (high affinity for water) or hydrophobic (low affinity for water) properties is used to facilitate the separation process, and water molecules 130 are selectively separated from the hygroscopic medium 104 at temperatures above the LCST. In some embodiments, the selected membrane 128 can include a fabricated multilayer structure including selective and protective layers, which can provide enhanced physical, chemical, mechanical, and / or thermal properties for improved performance and stability. In short, the membrane 128 in an aqueous environment has an attractive or repulsive force toward water. The material composition and corresponding surface chemistry of the selected membrane 128 can determine its interaction with water. For example, if a hydrophilic membrane is used, water molecules are selectively allowed to pass through the membrane on the permeate side, while hygroscopic media molecules, which are hydrophobic above the LCST, are retained on the retentate side of the membrane.In some examples, the hydrophilic membrane includes, but is not limited to, polyvinylpyrrolidone (PVP), polyethersulfone (PES), and / or polyacrylonitrile (PAN). When a hydrophobic membrane is used, hygroscopic media molecules are passed through the membrane to the permeate side at a temperature above the LCST, and the extracted water is retained in the retentate side. In some examples, the hydrophobic membrane includes, but is not limited to, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polysulfone (PS), and / or polypropylene (PP). In some embodiments, the pore size or molecular weight cut-off (MWCO) of the membrane 128 is optimized to accommodate the rotational speed of the centrifuge to avoid membrane damage. In certain embodiments, when a porous hydrophilic membrane is used, the extract water on the retentate side of the membrane may contain small amounts of residual hygroscopic media. In such examples, the retentate may be washed one or more times with the extract water in a closed loop to further improve the purity of the collected water.

[0017] In certain embodiments, two-phase liquids may be separated via a pressure-driven membrane configuration (FIG. 5) that also utilizes a porous membrane 128. The separation or extraction unit 106 may include one or more nanofiltration membrane modules, and the dilute hygroscopic medium 116 below the LCST is passed through the modules at a desired pressure. In some embodiments, pressures of about 3 bar to 10 bar, or about 15 bar or less, or about 5 bar or more are used to force the captured water through the nanofiltration membrane and / or ultrafiltration. In some embodiments, the selected membrane 128 may comprise an engineered multilayer structure including a selective layer and a protective layer, which may provide enhanced physical, chemical, mechanical, and / or thermal properties for improved performance and stability. In certain embodiments, the membrane module is configured to operate in batch or continuous mode to fit the overall AWG system configuration. The membrane separation is performed at a temperature above the LCST, which allows the dilute hygroscopic medium 116 to phase separate into a hygroscopic medium phase 104 and a captured water phase 130. In some embodiments, the flow rate of the process stream can be varied to improve separation efficiency. Once the dilute hygroscopic medium 116 has been phase-separated in this manner, the trapped water 130 can be drained or removed from the bottom of the separator 106. As an example, a porous membrane 128 with hydrophilic (high affinity for water) or hydrophobic (low affinity for water) properties can be used to facilitate the separation process, with water molecules 130 selectively separated from the hygroscopic thermally responsive medium 104 at temperatures above the LCST. Briefly, the membrane 128 in an aqueous environment has an attractive or repulsive response to water. The material composition and corresponding surface chemistry of the selected membrane 128 can determine its interaction with water. For example, if a hydrophilic membrane is used, water molecules are selectively allowed to pass through the membrane to the permeate side, while hygroscopic medium molecules, which are hydrophobic above the LCST, are retained on the retentate side of the membrane. In some examples, the hydrophilic membrane includes, but is not limited to, polyvinylpyrrolidone (PVP), polyethersulfone (PES), and / or polyacrylonitrile (PAN).On the other hand, when a hydrophobic membrane is used, hygroscopic fluid molecules can pass through the membrane to the permeate side at temperatures above the LCST, and the extracted water is retained in the retentate side. In some examples, the hydrophobic membrane may include, but is not limited to, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polysulfone (PS), and / or polypropylene (PP). In some embodiments, the pore size or molecular weight cut-off (MWCO) of the membrane 128 is optimized for the operating pressure to avoid membrane damage. In certain embodiments, when a porous hydrophilic membrane is used, the extract water on the retentate side of the membrane may contain small amounts of residual hygroscopic media. In such cases, the retentate can be washed one or more times with the extract water in a closed loop to further increase the purity of the recovered water. In certain embodiments, the membrane module can be maintained at a temperature above the LCST of the hygroscopic thermo-responsive media, which is concentration-dependent. In some embodiments, the membrane module is maintained at a temperature below about 90°C. In some embodiments, the LCST of the hygroscopic thermally responsive medium can be at least about 25° C. or less, at least about 30° C. or less, or at least about 45° C. or less. In certain embodiments, direct sunlight can be used, which can raise the temperature of the membrane module to about 45° C. or greater. Concentrated sunlight, on the other hand, can be used to raise the desired temperature to reach the LCST of the dilute hygroscopic medium, which in some instances is up to about 75° C.

[0018] In certain cases, hygroscopic media can be used that respond to specific gases. In such cases, the hygroscopic media can have additional functional groups added to their molecular structure so that they form a two-phase liquid-liquid solution upon the introduction of a specific gas. Examples of gases that hygroscopic media react with include nitrogen, carbon dioxide, and oxygen. Hygroscopic media may also respond to other gases not listed. In certain cases, hygroscopic media may respond to multiple gases that are introduced, such as nitrogen and oxygen. In certain cases, energy in the form of heat can also be added to the gas-responsive media to promote two-phase liquid-liquid separation.

[0019] In certain cases, hygroscopic media that respond to magnetic fields can be used. In such cases, by incorporating high-spin transition metal ions into the molecular structure of conventional hygroscopic media, thermoresponsive magnetic hygroscopic media can be obtained that form two-phase liquid-liquid solutions upon the introduction of a magnetic field. In some examples, components of thermoresponsive magnetic hygroscopic media can include, but are not limited to, octyltrimethylammonium bromotrichloroferrate, dodecyltrimethylammonium tetrachloroferrate, and / or 8-butyl-1,8-diazabicyclo[5.4.0]undec-7-ene bromotrichloroferrate. These hygroscopic properties, along with their thermal and magnetic responsiveness, make them promising candidates for atmospheric water generation.

[0020] 6A-6B, in certain embodiments, the hygroscopic medium can be contacted with moist air within an absorption chamber of an ambient air generating system as part of a method of operating the same. In operation, ambient air (at ambient temperature and humidity level) may be directed into the absorption chamber (also referred to herein as the absorber). In certain embodiments, a blower may be implemented at the air intake to the absorber to increase the volumetric flow rate of the ambient air entering the absorber. In the absorber, the ambient air comes into contact with the rich hygroscopic medium, which is fed to the absorber as a homogeneous fluid at a low temperature, thereby reducing the vapor pressure within the absorber and causing water vapor in the moist ambient air to condense and be absorbed into the hygroscopic fluid. As the ambient air and hygroscopic fluid flow through the absorber, moisture in the air condenses or is otherwise absorbed into the hygroscopic medium, diluting the hygroscopic medium and drying the air. The dry air is returned from the absorber to the atmosphere. A blower may be incorporated into the ambient air outlet of the absorber to increase the volumetric flow rate of air through the absorber. This blower can be provided in addition to, or as an alternative to, the blower located at the air inlet around the absorber. Furthermore, after the hygroscopic thermally responsive fluid passes through the absorber, a diluted, but still cool, hygroscopic fluid can exit the absorber. In certain embodiments, the absorber has a counterflow configuration, with ambient air entering the absorber near its bottom. Dry ambient air is exhausted near the top of the absorber (a pump / blower is optionally utilized to move air through the absorber). The highly hygroscopic liquid approaches the top of the absorber through a flow path and flows down the interior of the absorber by gravity. Water is absorbed from the ambient air into the hygroscopic fluid, and the lean hygroscopic medium exits near the bottom of the absorber. Flow conditioners, such as barriers, mesh, and / or bends in the outlet piping from the absorber, can be used to reduce carryover of the hygroscopic fluid at the absorber's air outlet. The flow conditioner can be placed inside the absorber adjacent the top of the absorber (eg, at the vent opening through which dry ambient air passes and exits the absorber).In some examples, the absorber can be operated in a cross-flow configuration, where air enters the absorber from one side and crosses (e.g., at least substantially horizontally) to the other side. The highly hygroscopic fluid medium may enter the absorber at the top and absorb moisture from the ambient air while flowing to a lower level within the absorber, with the lean hygroscopic medium being discharged near the bottom. In this manner, the air flow is at least substantially perpendicular to the flow of the hygroscopic fluid within the absorber. In this configuration, the air inlet and air outlet are at approximately the same height within the absorber. In certain configurations, the absorber can be operated in a cross-counterflow configuration, where air enters the absorber from one side and crosses to the other side. The highly hygroscopic liquid approaches the top of the absorber and flows to a lower level within the absorber while absorbing moisture from the ambient air, while the lean hygroscopic medium approaches the bottom of the absorber and is discharged. In this configuration, the air inlet and air outlet may be offset in height from each other. In this configuration, the air inlet can be on the side of the absorber near the top of the absorber, and the air discharge can be on the side of the absorber near the bottom. In another orientation of this configuration, the air inlet can be located on the side of the absorber near the bottom of the absorber, and the air discharge can be located on the opposite side of the absorber near the top of the absorber. In this way, the air path can travel diagonally through the absorber from the top to the bottom of the absorber, or from the bottom to the top of the absorber.

[0021] 2, the interior of the absorber 102 may include multiple packing elements 136 through which the rich hygroscopic medium 104 flows as it absorbs water 130 extracted from the humid ambient air 132. The packing elements 136 may be provided to increase the surface area of ​​the rich hygroscopic fluid 104 flowing within the absorber 102 and to provide a complex, tortuous flow path for the ambient air 132 flowing within the absorber 102, causing the air 132 to flow turbulently within the absorber 102. The absorber 102 may be embodied as a counterflow column as described above, with the rich hygroscopic medium 104 entering the absorber 102 through a hygroscopic column inlet 112 located at or near the top of the absorber 102 and an ambient air inlet 112b located at the bottom of the absorber 102. Ambient air 132 flows upward to a dry air exhaust 108b located at or near the top of the absorber 102, and the hygroscopic fluid 104 flows downward through packing elements 136 to a lean hygroscopic media fluid outlet 108 of the absorber 102. By way of example, the packing elements 136 may include individual blocks, bowls, trays, baffles, and / or any other shape defining a plurality of baffles, slits, holes, mesh, and / or other flow-modifying elements that may be positioned within the absorber 102 to collectively define a highly tortuous path for the ambient air 132 and hygroscopic media 104 through the absorber 102. The packing elements 136 may be made of (or formed from) a material that is non-reactive with the hygroscopic media 104. In certain embodiments, multiple packing elements 136 may be positioned within the absorber 102 without the packing elements 136 being physically connected to one another. In other embodiments, a single packing element sized and shaped specifically for the interior of the absorber may be provided and placed within the absorber 102. The packing elements 136 of certain embodiments may be arranged in a structured configuration to define flow paths set at different angles to one another, with or without perforations that collectively define structured flow paths for the ambient air 132 and / or hygroscopic media 104 flowing through the absorber 102. To provide a structured packing configuration, the packing elements 136 may be arranged in the absorber in an ordered stacked manner, as shown in FIG.The packing elements 136 may also be randomly arranged, for example, multiple geometrically shaped components may be randomly arranged within the absorber 102 to increase surface area. Although described as a packing-based absorber, it should be understood that the hygroscopic medium 104 may be passed through the absorber via other configurations, such as by atomizing the liquid hygroscopic medium, by spraying the hygroscopic medium within the absorber, etc.

[0022] Returning to Figures 6A and 6B, the lean hygroscopic medium (or "lean hygroscopic fluid") can exit the absorber to a pump. In some operations, the absorber can be operated in a batch configuration, in which case a series of valves recirculate the lean hygroscopic fluid along the flow path (while preventing additional high-concentration hygroscopic fluid from entering the closed loop while appropriate valves remain closed), and can be configured to cool the lean hygroscopic fluid through a pre-absorber heat exchanger (e.g., a shell-and-tube heat exchanger, a plate heat exchanger, etc.) (on the other side of the heat exchanger is cooling water recovered from the overall system) before returning it to the top of the absorber. In this way, the amount of water absorbed into the hygroscopic fluid can be increased (thereby increasing the dilution level of the hygroscopic medium) before the hygroscopic fluid is directed to the separation portion of the overall system. In certain embodiments, the absorber chamber can utilize rotating air without packing material to facilitate mass transfer of water to the hygroscopic medium. In certain cases, the chamber can be conical in shape to enable interaction. In certain cases, it may be cylindrical. In certain embodiments, the absorption chamber itself can be mechanically rotated to induce a hypergravity environment to assist in the absorption of water into and / or onto the hygroscopic-rich fluid. In certain embodiments, the absorption chamber can also be used as a separation chamber, whose function is changed after a certain amount of water has been absorbed. In certain embodiments, the pre-absorber heat exchanger is cooled using a chiller that uses a cooling medium, such as water or glycol, on the other side of the heat exchanger to cool the rich hygroscopic medium along the flow path. The absorber can be operated in a continuous configuration, with a valve configured to recirculate a portion of the lean hygroscopic medium. In this configuration, a certain amount of the lean hygroscopic medium may be recirculated to the input of the absorber via a pre-absorber heat exchanger (e.g., a shell-and-tube heat exchanger, a plate heat exchanger, etc.) to cool the lean hygroscopic fluid before being returned to the top of the absorber (the other side of the heat exchanger may be cooled using water recovered from the overall system, as described in more detail herein). Another portion of the lean hygroscopic fluid may simultaneously pass to a separation vessel as described herein.In certain embodiments, the absorber may be configured so that the rich hygroscopic fluid is not cooled in a heat exchanger. In this embodiment, cooling of the hygroscopic fluid can occur via conductive heat exchange with ambient air via a heat transfer pipe. Cooling of the fluid occurs in the absorber as sensible heat exchange with the atmosphere, provided that the ambient temperature is lower than the inlet temperature of the hygroscopic medium. In certain embodiments, the absorber may be configured so that the diluted fluid exits the absorber and is sent to a separation vessel without a recirculation path. The rich hygroscopic fluid returning from the separation vessel may or may not be cooled in a heat exchanger and / or a cooler and / or geothermal cooling before entering the absorber. In other embodiments, Joule-Thompson cooling (using a sudden change in pressure of the hygroscopic medium (or a gas in contact with the hygroscopic medium)) can be used to cool the hygroscopic medium.

[0023] Referring again to FIG. 2 , after the fluid passes through the absorber 102, it may be routed along a flow path to a separation vessel 106. The separation vessel may include one or more energy exchange devices 120, such as heat exchangers, heaters, heat sinks, geothermal heaters, solar heaters, etc., configured to elevate the temperature of the hygroscopic medium 104. In certain embodiments, the one or more energy exchange devices 120 may be internal and / or external to the separation vessel 106. In other embodiments, the one or more energy exchange devices 120 may be embodied as separate devices in series along the flow path. In other embodiments, the separation vessel 106 may be jacketed to maintain the vessel's internal temperature. Once the dilute hygroscopic fluid 116 passes through the energy exchange device 120 and rises above the critical temperature of the hygroscopic medium 104, it may separate into two phases: one consisting of entrapped water 130 and one consisting of the hygroscopic medium 104. The density difference between the phases and the hydrophobicity of the hygroscopic fluid above its lower critical solution temperature can result in bulk separation of the hygroscopic fluid 104 and water 130. In certain embodiments, the energy exchange device 120 can be configured to cool the hygroscopic fluid below its upper critical solution temperature. After cooling, the dilute hygroscopic fluid 116 can separate into a water-rich phase consisting of the entrapped water 130 and a hygroscopic-fluid-rich phase consisting of the hygroscopic medium 104. The density difference between the phases and the hydrophobicity of the hygroscopic fluid below its upper critical solution temperature can result in bulk separation of the hygroscopic fluid 104 and water 130. The separation vessel 106 can be configured to enable two-phase liquid-liquid separation of the liquid water 130 absorbed by the hygroscopic fluid 104 and the hygroscopic fluid 104 itself. Thus, as shown, one liquid phase (e.g., water 130) may be withdrawn from the top of the separation vessel 106 and another liquid phase (e.g., hygroscopic medium 104) may be withdrawn at the bottom of the separation vessel 106. In certain embodiments, the inlet to the separation vessel 106 may be near the center of the separation vessel 106. In other embodiments, the inlet to the separation vessel 106 may be near the top of the separation vessel 106. In other embodiments, the inlet 110 to the separation vessel 106 may be near the bottom of the separation vessel 106, as shown.In certain embodiments, the inlet 110 to the separation vessel 106 can be varied depending on the amount of separation desired.

[0024] In certain embodiments, the separation vessel 106 may be comprised of a vessel containing multiple horizontal plates, baffles, and / or the like. The plates may have through-holes extending through the top and bottom surfaces of the plates to allow fluid to pass through. In certain embodiments, the plates may have support rods attached to all plates in the separation vessel, e.g., extending through the center of the plates. In certain embodiments, a rod is rigidly connected to all plates, and the rod reciprocates within the vessel (e.g., up and down via an actuator) to cause agitation of the hygroscopic fluid within the separation vessel. In other embodiments, the separation vessel 106 may not include plates and may simply consist of a vessel with a single inlet and two outlets. In certain embodiments, the separation vessel 106 may include a membrane with pores that allow water to pass through the membrane while inhibiting the flow of the hygroscopic fluid through the membrane. In this configuration, a pump can be used to increase the pressure of the incoming hygroscopic fluid. In certain embodiments, the separation vessel may be microscale and / or laser-etched onto a silicone (or other material) substrate. In this configuration, multiple separation vessels can be etched onto a single substrate. In this configuration, the separation vessels may form a T-shaped vessel. Multiple laser-etched substrates may share a common inlet header. The flow from the T-shaped vessels is routed to a common outlet.

[0025] In certain embodiments, the water-rich hygroscopic fluid, including the captured water 130 separated in the separation vessel 106, can be sent through another separation vessel having a configuration similar to the first separation vessel. This can further purify the fluid. The water-rich hygroscopic fluid enters the separation vessel and can again separate into two phases, for example, based at least in part on density and hydrophobicity. The water-rich phase can be separated from the hygroscopic-rich phase within the separation vessel. In certain embodiments, energy can be input via one or more energy exchange devices, such as a heat exchanger, heater, heat sink, geothermal heater, and / or solar heater, before entering the second separation vessel.

[0026] In certain embodiments, a gas-responsive hygroscopic fluid may be used in an absorption chamber, as described above, to capture water from moist air. Once at least partially saturated (diluted), the hygroscopic fluid is delivered to a separation vessel. In certain embodiments, a gas may be introduced into the hygroscopic fluid before delivery to the separation vessel. In this embodiment, the piping for transporting the hygroscopic fluid may be cylindrical. In certain embodiments, obstacles, such as baffles, packing, or materials specifically designed to create turbulence or tortuous flow, may be placed in the piping to promote mixing of the gas and hygroscopic fluid. In certain embodiments, a gas may be bubbled through the hygroscopic fluid in the separation vessel. In this example, the gas is introduced into the hygroscopic fluid near the bottom of the separation vessel. Due to the density difference between the gas and the hygroscopic fluid, the gas may migrate upward through the hygroscopic fluid. In this embodiment, the water-rich hygroscopic fluid may be introduced into the separation vessel near the middle of the separation vessel. In certain embodiments, the water-rich hygroscopic fluid may be introduced into the separation vessel near the top of the vessel. In certain embodiments, the water-rich hygroscopic fluid may be introduced into the separation vessel adjacent to the bottom of the separation vessel. In certain embodiments, the separation vessel may include an actuation plate as described above. In certain embodiments, the separation vessel may be constructed from a material specifically designed to create turbulent and tortuous upward gas flow through the separation vessel. Examples of this design include 3D printed structures that promote the dispersion of gas bubbles.

[0027] As described above, separation of the hygroscopic fluid from the water occurs in the separation vessel 106. Once the water-rich liquid phase is separated from the hygroscopic fluid, the water-rich liquid phase can be sent to another process for further purification. This process may be another separation process in the form of membrane separation, such as nanofiltration, membrane distillation, mechanical vapor compression, distillation, reverse osmosis, electrodialysis, and / or a combination of these techniques. As described above, such a purification process ensures that all or substantially all of the hygroscopic fluid is captured, and the hygroscopic fluid may be replenished for storage. The hygroscopic-rich liquid phase, including the hygroscopic medium 104, may exit the separation vessel 196 and be sent back to the absorber 102. Prior to entering the absorber 102, the hygroscopic fluid 104 may be sent to an energy exchange device (e.g., a chiller, a heat exchanger, a geothermal cooling loop, etc.) 122 to cool the hygroscopic fluid 104 below a critical temperature. The hygroscopic fluid 104 may then be placed in the absorber 102 as described above. In certain embodiments, the water-rich hygroscopic fluid 104 removed from the separation vessel 106 may be sent to a subsequent vessel and / or multiple vessels to enable a multi-stage process.

[0028] Certain embodiments of the atmospheric water generating system discussed herein can be configured to operate in a continuous mode of operation, such that water is constantly or at least substantially constantly (during operation) extracted from the humid air in the absorption chamber while liquid water is extracted from the hygroscopic fluid in the extraction (separation) chamber, such that the hygroscopic fluid flows between the chambers. In other embodiments, the atmospheric water generating system can be configured for batch operation, for example, to accommodate temperature differences between day and night and / or to accommodate differences in atmospheric humidity. By way of example only, water can be extracted from the hygroscopic fluid by allowing the hygroscopic fluid to naturally cool during cooler nighttime temperatures. In such cases, the hygroscopic fluid is diluted in the absorption stage, and then water is extracted from the hygroscopic fluid in the extraction stage. Furthermore, certain embodiments can utilize waste heat from the water production process and / or waste heat from a third-party industrial process as part of the heat input to the water generating system described above. By way of example only, heat generated from flare gas at the head of an oil or gas well can be utilized to provide the input heat to the water production process described above. In yet another embodiment, waste heat from electronic equipment, such as heat generated by server farms, electrical equipment, etc., can be utilized to heat the hygroscopic fluid while simultaneously providing the necessary heat transfer from the electronic equipment for optimal performance. In certain embodiments, the hygroscopic fluid, and more specifically the chemical composition of the hygroscopic fluid, can be tailored to enhance heat transfer properties and thereby provide efficient cooling to the electronic equipment.

[0029] As described above, the dried atmospheric air 134 may be vented to the atmosphere after the water 130 is absorbed from the atmospheric air stream 132. In other embodiments, after the water 130 is extracted from the air 132, the dried air 134 may be passed through one or more gas extraction stages 118. For example, a carbon dioxide extraction stage may be provided to extract and capture carbon dioxide from the air stream. As another example, oxygen may be extracted and captured from the air stream. As yet another example, argon may be extracted and captured from the air stream. In certain embodiments, each of multiple gases may be extracted through each stage of the gas extraction process. These stages may be optimized to capture each gas before other gases to increase the efficiency of gas capture. It is understood that certain gases may be more easily captured before or after humidity is extracted from the air. It is further understood that the chemical makeup of certain gases may facilitate their extraction before other gases. Furthermore, individual gas extraction stages 118 may be heated and / or cooled as needed to optimize gas capture.

[0030] The subject matter of the present disclosure may also relate to the following aspects.

[0031] The first aspect relates to an atmospheric water generating system 100 comprising an absorption chamber 102 configured to facilitate absorption or adsorption of water 130 from atmospheric or ambient air 132 into and / or onto a hygroscopic medium 104, and a separation vessel 106 in fluid communication with the absorption chamber 102 for extracting the absorbed or adsorbed water 130 from the hygroscopic medium 104.

[0032] The second embodiment relates to the atmospheric water generating system 100 of the first embodiment, wherein the hygroscopic medium 104 is responsive to a change in energy and / or mixing with a particular gas.

[0033] A third embodiment relates to the atmospheric water generating system 100 of any of the preceding embodiments, wherein the hygroscopic medium 104 has an upper critical solution temperature (UCST) or a lower critical solution temperature (LCST), and the hygroscopic medium 104 is a hygroscopic thermally responsive medium.

[0034] A fourth embodiment relates to the atmospheric water generating system 100 of the preceding embodiment, wherein the LCST is at least about 25°C or less, at least about 30°C or less, or at least about 45°C or less, and / or up to about 75°C.

[0035] A fifth embodiment relates to the atmospheric water generating system 100 of any preceding embodiment, wherein the hygroscopic medium 104 comprises an ionic liquid, a polymer, an organic solvent, and / or salt water.

[0036] A sixth embodiment relates to the atmospheric water generating system 100 of any preceding embodiment, wherein the hygroscopic medium 104, and / or the hygroscopic medium 104 containing absorbed or adsorbed water 130, has a viscosity of less than about 500 millipascal·seconds (mPa·s) under operative conditions of the atmospheric water generating system 100.

[0037] A seventh embodiment relates to an atmospheric water generating system 100 of any of the preceding embodiments, wherein the outlet 108 of the absorption chamber 102 is in fluid communication with the inlet 110 to the separation vessel 106 and the inlet 112 of the absorption chamber 102 is in fluid communication with the outlet 114 of the separation vessel 106, thereby defining a closed loop for (a) delivering a dilute hygroscopic medium 116 comprising the hygroscopic medium 104 having absorbed or adsorbed water 130 to the separation vessel 106 and (b) returning the hygroscopic medium 104 to the absorption chamber 102 after extraction of the absorbed or adsorbed water 130.

[0038] The eighth embodiment relates to the atmospheric water generating system 100 of the preceding embodiment, wherein the inlet 112 of the absorption chamber 102 is a first inlet 112a for introducing the hygroscopic medium 104 into the absorption chamber 102, the outlet 108 of the absorption chamber 102 is a first outlet 108a for removing the lean hygroscopic medium 116 from the absorption chamber, and the absorption chamber 102 further comprises a second inlet 112b for introducing atmospheric or ambient air 132 into the absorption chamber 102 and a second outlet 108b for removing dry air 134 from the absorption chamber 102.

[0039] A ninth embodiment relates to the atmospheric water generating system 100 of the preceding embodiment, further including a gas extraction stage 118 in fluid communication with the second outlet 108b of the absorption chamber 102 for removing one or more gases from the dry air.

[0040] A tenth aspect relates to the atmospheric water generating system 100 of any one of the seventh to ninth aspects, wherein the separation vessel 106 is configured for heating and / or cooling and / or an energy exchange device 120 is disposed between the absorption chamber outlet 108 and the inlet 110 to the separation vessel 106 to heat the lean hygroscopic medium 116.

[0041] An eleventh embodiment relates to the atmospheric water generating system 100 of any one of the seventh to tenth embodiments, further comprising an energy exchange device 122 disposed between the outlet 114 of the separation vessel 106 and the inlet 112 of the absorption chamber 102 to cool the hygroscopic medium 104 before returning the hygroscopic medium 104 to the absorption chamber 102.

[0042] A twelfth aspect relates to the atmospheric water generating system 100 of any one of the seventh to eleventh aspects, wherein the outlet 114 of the separation vessel is a first outlet 114a, and the separation vessel 106 further comprises a second outlet 114b for removing absorbed or adsorbed water 130 after extraction.

[0043] A thirteenth embodiment relates to the atmospheric water generating system 100 of any preceding embodiment, wherein the absorption chamber 102 includes one or more packing components 136 configured to modify the flow of atmospheric or ambient air 132 and / or the flow of the hygroscopic medium 104.

[0044] A fourteenth aspect relates to the atmospheric water generating system 100 of any of the preceding aspects, wherein the absorption chamber 102 is configured to utilize rotating air.

[0045] A fifteenth embodiment relates to the atmospheric water generating system 100 of any of the preceding embodiments, wherein the separation vessel 106 comprises a settling tank 124 .

[0046] A sixteenth embodiment relates to the atmospheric water generating system of any preceding embodiment, wherein the separation vessel 106 has a centrifugally driven liquid-liquid extractor 126.

[0047] A seventeenth embodiment relates to the atmospheric water generating system 100 of any of the preceding embodiments, wherein the separation vessel 106 has a porous membrane 128 .

[0048] An eighteenth embodiment relates to the atmospheric water generating system 100 of the preceding embodiment, wherein the porous membrane 128 is hydrophilic.

[0049] A nineteenth embodiment relates to the atmospheric water generating system 100 of the seventeenth or eighteenth embodiment, wherein the porous membrane 128 comprises polyvinylpyrrolidone (PVP), polyethersulfone (PES), and / or polyacrylonitrile (PAN).

[0050] A twentieth embodiment relates to the atmospheric water generating system 100 of the seventeenth embodiment, wherein the porous membrane 128 is hydrophobic.

[0051] A twenty-first embodiment relates to the atmospheric water generating system 100 of the preceding embodiment, wherein the porous membrane 128 comprises polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polysulfone (PS), and / or polypropylene (PP).

[0052] A twenty-second embodiment relates to a method of producing purified water using the atmospheric water generating system 100 of any of the preceding embodiments.

[0053] A twenty-third aspect relates to a method for producing water from a moist gas, the method comprising: introducing a stream of moist gas into a hygroscopic liquid medium 104, the moist gas preferably being supplied from the ambient atmosphere 132, the hygroscopic liquid medium 104 having an upper critical solution temperature (UCST) or a lower critical solution temperature (LCST), and maintaining the temperature of the hygroscopic liquid medium above its UCST or below its LCST while introducing the moist gas for a period of time to allow the hygroscopic liquid medium 104 to absorb water 130 from the moist gas. , thereby forming a homogeneous wet hygroscopic liquid medium (or dilute hygroscopic medium) 116; lowering the temperature of the wet or dilute hygroscopic liquid medium 116 to a temperature below its UCST, thereby causing the water 130 to form a separate phase from the hygroscopic liquid medium 104, or raising the temperature of the wet or dilute hygroscopic liquid medium 116 to a temperature above its LCST, thereby causing the water 130 to form a separate liquid phase from the hygroscopic liquid medium 104, and extracting the liquid water 130.

[0054] A twenty-fourth embodiment relates to the method of the preceding embodiment, wherein a moist gas stream (e.g., ambient air 132) is introduced into the hygroscopic liquid medium 104 in the first (absorption) vessel 102, a homogeneous moist or lean hygroscopic liquid medium 116 is removed from the first vessel 102 and transferred to a second (separation) vessel 106, and the temperature of the homogeneous moist or lean hygroscopic liquid medium 116 is reduced or increased after removal from the first (absorption) vessel 102.

[0055] A twenty-fifth embodiment relates to the method of any preceding embodiment, wherein the wet or lean hygroscopic medium 116 is sent to one or more subsequent vessels to allow further separation of the hygroscopic medium 104 from the water 130, forming a multi-stage separation process.

[0056] A twenty-sixth embodiment relates to the method of any of the preceding embodiments, wherein the water is extracted by passing it through a separator membrane 128 that is impermeable to the hygroscopic liquid medium 104 .

[0057] A twenty-seventh embodiment relates to the method of any of the preceding embodiments, wherein the liquid water 130 is extracted by allowing the wet or lean hygroscopic liquid medium 116 to separate into two liquid phases by gravitational settling (e.g., in a settling tank 124) and then withdrawing the liquid water phase 130.

[0058] A twenty-eighth embodiment relates to the method of any preceding embodiment, further comprising centrifuging the wet or lean hygroscopic liquid medium 116 to facilitate separation of the liquid water phase 130 from the hygroscopic liquid medium phase 104.

[0059] A twenty-ninth embodiment relates to the method of any preceding embodiment, wherein the hygroscopic liquid medium 104 comprises an ionic liquid, a polymer, an organic solvent, and / or salt water.

[0060] In a thirtieth embodiment, the hygroscopic liquid medium 104 is selected from the group consisting of tetrabutylphosphonium bromide, tetrabutylphosphonium chloride, tetrabutylphosphonium trifluoroacetate, tributyl(octyl)phosphonium bromide, poly(N-isopropylacrylamide), 1-hexyl-3-methylimidazolium bromide, tributylhexylphosphonium bromide, a double salt of 1,3-dimethylimidazolium iodide and tetrabutylphosphonium 2,4-dimethylbenzenesulfonate, tetrabutylphosphonium trifluoroacetate, tetrabutylphosphonium mesitylenesulfonate, tributyloctylphosphonium bromide, tetrabutylphosphonium p-toluenesulfonate, tetrabutylphosphonium N-trifluoromethanesulfonylleucine salt, [N 4444 ][TMBS], [N 4444 ]CF3COO,[P 4444 ][Sal], [P 4444 ][SS], or [N 4444 ]CF3COO,[P 4444

[0037] [Mal], or a mixture thereof.

[0061] A thirty-first embodiment relates to the method of any preceding embodiment, further comprising, after extracting the liquid water 130 from the moist hygroscopic liquid medium 116, either increasing the temperature of the hygroscopic liquid medium above its UCST or decreasing the temperature of the hygroscopic liquid medium below its LCST, and introducing additional moist gas (e.g., ambient air 132) into the hygroscopic liquid medium 104.

[0062] A thirty-second embodiment relates to the method of any preceding embodiment, wherein the change in temperature between increasing and decreasing the temperature of the hygroscopic liquid medium 104 above its UCST to below its UCST, or between decreasing and increasing the temperature of the hygroscopic liquid medium 104 below its LCST to above its LCST, is less than a 25°C temperature change, preferably less than a 15°C temperature change, and more preferably less than a 10°C temperature change.

[0063] A thirty-third embodiment relates to the method of any preceding embodiment, wherein the maximum temperature of the hygroscopic liquid medium 104 during the method is less than 90°C, preferably less than 75°C, and more preferably less than 60°C.

[0064] Although the present invention has been described in considerable detail with reference to specific embodiments thereof, other embodiments are possible without departing from the invention. Accordingly, the spirit and scope of the appended claims should not be limited to the description of the preferred embodiments contained herein. All embodiments that come within the meaning of the claims, whether literally or equivalently, are intended to be embraced therein.

[0065] Furthermore, the advantages described above are not necessarily the only advantages of the present invention, and it is not necessarily expected that all of the described advantages will be achieved in every embodiment of the present invention.

Claims

1. an absorption chamber configured to facilitate absorption or adsorption of water from atmospheric or ambient air into and / or onto the hygroscopic medium; a separation vessel in fluid communication with the absorption chamber for extracting absorbed or adsorbed water from the hygroscopic medium.

2. 10. The atmospheric water generating system of claim 1, wherein the hygroscopic medium is responsive to a change in energy and / or mixing with a specific gas.

3. 10. The atmospheric water generating system of claim 1, wherein the hygroscopic medium has an upper critical solution temperature (UCST) or a lower critical solution temperature (LCST), and the hygroscopic medium is a hygroscopic thermally responsive medium.

4. The atmospheric water generating system of claim 3 , wherein the LCST is at least about 25° C. or less.

5. The atmospheric water generating system of claim 1 , wherein the hygroscopic medium comprises an ionic liquid, a polymer, an organic solvent, and / or salt water.

6. 10. The atmospheric water generating system of claim 1, wherein the hygroscopic medium and / or the hygroscopic medium containing the absorbed or adsorbed water has a viscosity of less than about 500 millipascal-seconds (mPa·s) under operative conditions of the atmospheric water generating system.

7. an outlet of the absorption chamber in fluid communication with an inlet to the separation vessel; the inlet of the absorption chamber is in fluid communication with the outlet of the separation vessel; 10. The atmospheric water generating system of claim 1, thereby defining a closed loop for (a) delivering a dilute hygroscopic medium containing the hygroscopic medium with the absorbed or adsorbed water to the separation vessel, and (b) returning the hygroscopic medium to the absorption chamber after extraction of the absorbed or adsorbed water.

8. the inlet of the absorption chamber is a first inlet for introducing the hygroscopic medium into the absorption chamber; the outlet of the absorption chamber is a first outlet for removing the dilute hygroscopic medium from the absorption chamber; The absorption chamber comprises: a second inlet for introducing the atmospheric or ambient air into the absorption chamber; 8. The atmospheric water generating system of claim 7, further comprising: a second outlet for removing dry air from the absorption chamber.

9. 10. The atmospheric water generating system of claim 8, further comprising a gas extraction stage in fluid communication with the second outlet of the absorption chamber for removing one or more gases from the dry air.

10. the separation vessel is configured for heating; and / or 8. The atmospheric water generating system of claim 7, wherein an energy exchange device is disposed between the outlet of the absorption chamber and the inlet to the separation vessel for heating the lean hygroscopic medium.

11. 8. The atmospheric water generating system of claim 7, further comprising an energy exchange device disposed between the outlet of the separation vessel and the inlet of the absorption chamber for cooling the hygroscopic medium before returning it to the absorption chamber.

12. the outlet of the separation container is a first outlet, 8. The atmospheric water generating system of claim 7, wherein the separation vessel further comprises a second outlet for removing the absorbed or adsorbed water after the extraction.

13. The atmospheric water generating system of claim 1 , wherein the absorption chamber includes one or more packing components configured to modify the flow of the atmospheric or ambient air and / or the flow of the hygroscopic medium.

14. The atmospheric water generating system of claim 1 , wherein the absorption chamber is configured to utilize rotating air.

15. The atmospheric water generating system of claim 1 , wherein the separation vessel comprises a settling tank.

16. The atmospheric water generating system of claim 1 , wherein the separation vessel comprises a centrifugally driven liquid-liquid extractor.

17. The atmospheric water generating system of claim 1 , wherein the separation vessel comprises a porous membrane.

18. 18. The atmospheric water generating system of claim 17, wherein the porous membrane is hydrophilic.

19. 20. The atmospheric water generating system of claim 18, wherein the porous membrane comprises polyvinylpyrrolidone (PVP), polyethersulfone (PES), and / or polyacrylonitrile (PAN).

20. 18. The atmospheric water generating system of claim 17, wherein the porous membrane is hydrophobic.

21. 21. The atmospheric water generating system of claim 20, wherein the porous membrane comprises polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polysulfone (PS), and / or polypropylene (PP).

22. 10. A method for producing purified water using the atmospheric water generating system of claim 1.

23. introducing a stream of moisture-laden gas into a hygroscopic liquid medium, said moisture-laden gas preferably being supplied from the ambient atmosphere, said hygroscopic liquid medium having an upper critical solution temperature (UCST) or a lower critical solution temperature (LCST); maintaining the temperature of the hygroscopic liquid medium above its UCST or below its LCST while introducing the moist gas for a period of time to allow the hygroscopic liquid medium to absorb water from the moist gas, thereby forming a homogeneous moist hygroscopic liquid medium; reducing the temperature of the water-laden hygroscopic liquid medium to a temperature below its UCST, thereby causing the water to form a separate phase from the hygroscopic liquid medium, or increasing the temperature of the water-laden hygroscopic liquid medium to a temperature above its LCST, thereby causing the water to form a separate liquid phase from the hygroscopic liquid medium; and extracting the liquid water from the gas.

24. 24. The method of claim 23, wherein the moist gas stream is introduced into the hygroscopic liquid medium in a first vessel, the homogeneous moist hygroscopic liquid medium is removed from the first vessel and transferred to a second vessel, and the temperature of the homogeneous moist hygroscopic liquid medium is reduced or increased after removal from the first vessel.

25. 24. The method of claim 23, wherein the wet hygroscopic medium is sent to one or more subsequent vessels to allow further separation of the hygroscopic medium from the water, forming a multi-stage separation process.

26. 24. The method of claim 23, wherein the water is extracted by passing the water through a separation membrane that is impermeable to the hygroscopic liquid medium.

27. 24. The method of claim 23, wherein the liquid water is extracted by allowing the wet hygroscopic liquid medium to separate into two liquid phases by gravitational settling and then withdrawing the liquid water phase.

28. 24. The method of claim 23, further comprising centrifuging the wet hygroscopic liquid medium to facilitate the separation of the liquid water phase from the hygroscopic liquid medium phase.

29. 24. The method of claim 23, wherein the hygroscopic liquid medium comprises an ionic liquid, a polymer, an organic solvent, and / or salt water.

30. The hygroscopic liquid medium may be selected from the group consisting of tetrabutylphosphonium bromide, tetrabutylphosphonium chloride, tetrabutylphosphonium trifluoroacetate, tributyl(octyl)phosphonium bromide, poly(N-isopropylacrylamide), 1-hexyl-3-methylimidazolium bromide, tributylhexylphosphonium bromide, a double salt of 1,3-dimethylimidazolium iodide and tetrabutylphosphonium 2,4-dimethylbenzenesulfonate, tetrabutylphosphonium trifluoroacetate, tetrabutylphosphonium mesitylenesulfonate, tributyloctylphosphonium bromide, tetrabutylphosphonium p-toluenesulfonate, tetrabutylphosphonium N-trifluoromethanesulfonylleucine salt, [N ４４４４ ] [TMBS], [N ４４４４ ]CF ３ COO, [P ４４４４ ] [Sal] [P ４４４４ ][SS], or [N ４４４４ ]CF ３ COO, [P ４４４４ ] [Mal], or a mixture thereof.

31. 24. The method of claim 23, further comprising, after extracting the liquid water from the moist hygroscopic liquid medium, increasing the temperature of the hygroscopic liquid medium above its UCST or decreasing the temperature of the hygroscopic liquid medium below its LCST and introducing additional moisture-laden gas into the hygroscopic liquid medium.

32. 24. The method of claim 23, wherein the change in temperature between increasing and decreasing the temperature of the hygroscopic liquid medium above its UCST to below its UCST, or between decreasing and increasing the temperature of the hygroscopic liquid medium below its LCST to above its LCST, is less than 25°C.

33. 24. The method of claim 23, wherein the maximum temperature of the hygroscopic liquid medium during the method is less than 90°C.

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