System and method for atmospheric water extraction via desiccant adsorption and thermal liquid desorption

Abstract

A system and method for atmospheric water extraction is disclosed. The system includes at least one extraction structure, each having a desiccant material and movable between adsorption and desorption configurations. The system also includes a condensing chamber in fluidic communication with the extraction structure, the condensing chamber configured to receive and condense water vapor into liquid water on a cooling surface. The system also includes a heating subsystem that is thermal liquid-based, with the thermal liquid in thermal contact with a heat source. The adsorption configuration includes the extraction structure being exposed to an atmosphere such that the desiccant is in fluidic contact with an airflow. The desorption configuration includes the desiccant being in fluidic communication with the cooling surface and in thermal communication with the thermal liquid such that the desiccant is heated to at least a release temperature, causing the desiccant to release adsorbed water vapor.

Description

SYSTEM AND METHOD FOR ATMOSPHERIC WATER EXTRACTION VIA DESICCANT ADSORPTION AND THERMAL LIQUID DESORPTIONRELATED APPLICATIONS

[0001] This application claims the benefit of U.S. provisional patent application 63 / 580,352, filed September 1, 2023, titled “SYSTEM FOR ATMOSPHERIC WATER EXTRACTION VIA DESICCANT ADSORPTION COUPLED WITH THERMAL LIQUID DESORPTION.” the entirety of the disclosure of which is hereby incorporated by this reference.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

[0002] This work is partially funded by the National Science Foundation (EEC- 1449500) Nanosystems Engineering Research Center on Nanotechnology-Enabled Water Treatment. The government has certain rights in the invention.TECHNICAL FIELD

[0003] Aspects of this document relate generally to atmospheric water extraction.BACKGROUND

[0004] There is a finite amount of fresh water for human consumption, industrial use, and agriculture. Many communities in arid regions of the world are limited and often rely upon large infrastructure projects to move and import water long distances from oceans or sources of freshwater to meet current and growing water supplies. These infrastructure projects have high capital plus operating costs, and impact lands through which pipelines or canals transect. However, there is a large amount of water available in the air, an enormous volume that could be tapped into by those water-deprived and isolated locations without large-scale pipeline or canal infrastructure projects.

[0005] Another reason for the growing interest in atmospheric water extraction (AWE) technology is that the water extracted from the air is very pure, making this process ideal for many industrial or other water applications.

[0006] Removing water vapor in the atmosphere, or water dehumidification, is widely practiced at both the industrial and household level. However, these conventional systems require a significant amount of electrical energy for their operation (e.g., for heating, etc.). The current, commercial dehumidification devices on the market can be divided into two major categories: compressor-based and desiccant-based. A compressor-based system captures water vapor from the ambient air and condensates it to liquid water at its dew point temperature by exposing it to a cold surface that is typically cooled using a refrigerant-based cooling system. In contrast, a desiccant-based system extracts moisture from the ambient air through sorption, utilizing porous desiccant materials.

[0007] The desiccant-based system is attractive for several reasons. Desiccantbased systems have more reliable performance across a wider range of ambient air temperatures (e.g., 1-40 °C) and relative humidity (RH) conditions (e.g., 10 - 100% RH) than compressorbased systems. This makes desiccant-based systems more energy efficient at optimal conditions (e.g., above 25 °C and below 60% RH). Additionally, a desiccant-based device typically produces water of a higher quality than a compressor-based system. Compressorbased systems condense and produce liquid-water on cold surfaces, which unfortunately also separates particulates and volatile compounds from the air and into the water. Furthermore, the desiccant-based system does not use an energy-intensive refrigerant compressor and is more environmentally friendly for lower RH environments.

[0008] Although they are more energy efficient than compressor-based systems at low RH, conventional desiccant-based systems still require considerable energy, which can limit the utility of such a device. Various modes of operation (e.g., active, passive, etc.) exist for desiccant-based systems. Active mode systems use energy to operate fans (or blowers) that move air containing moisture across or through solid phase desiccants. Passive modes operate without fans and rely upon diffusion or wind to transport water vapor to the solid-phase desiccants. Currently, the current limiting factor for AWE by desiccants is the energy required to operate electric-powered heaters used to desorb captured water from the solid phase desiccant. Much more energy is required for this heating than to operate fans.

[0009] As a specific example, it theoretically takes 2,200-2,700 kJ of heat to evaporate 1kg of water (or about 0.7 kWh / L). However, the energy consumption for the dehumidification process and for desiccant regeneration would be much greater, roughly an additional 0.3 to 0.5 kWh / L. The heat in the desiccant system creates a difference in partial pressure of the water vapor, which drives the desorption process from the desiccator. The subsequently released hot, humid air is then condensed by ambient cool air.SUMMARY

[0010] According to one aspect, a system for atmospheric water extraction, includes at least one extraction structure, each extraction structure having a desiccant material. Each extraction structure is movable to an adsorption configuration, and also movable to a desorption configuration. The system also includes a condensing chamber coupled to and in fluidic communication with the at least one extraction structure, the condensing chamber having a cooling surface and configured to receive a water vapor from the at least one extraction structure and condense the water vapor into liquid water on the cooling surface. Additionally, the system includes a heating subsystem that is thermal liquid-based. The heating subsystem is coupled to the at least one extraction structure and has a thermal liquid in thermal contact with a heat source. For each extraction structure of the at least one extraction structure, the adsorption configuration includes the extraction structure being exposed to an atmosphere such that at least a first portion of the desiccant material of the extraction structure is in fluidic contact with an airflow having atmospheric water. For each extraction structure of the at least one extraction structure, the desorption configuration includes, the desiccant material of the extraction structure being in fluidic communication with the cooling surface of the condensing chamber. The desorption configuration also includes at least a second portion of the desiccant material in thermal communication with the thermal liquid such that at least the second portion of the desiccant material is heated to at least a release temperature, causing at least the second portion of the desiccant material to release adsorbed atmospheric water as water vapor. The first portion of the desiccant material includes the desiccant material in at least a partially unsaturated state. The second portion of the desiccant material includes the desiccant material in at least a partially saturated state.

[0011] Particular embodiments may comprise one or more of the following features. The system may further include an enclosure for each extraction structure of the at least one extraction structure. For each extraction structure of the at least one extraction structure, the desorption configuration may also include the extraction structure being enclosed inside the enclosure, isolated from the atmosphere. The desiccant material of the at least one extraction structure may remain stationary when the extraction structure moves from the adsorption configuration to the desorption configuration. The system may further include an enclosure for each extraction structure of the at least one extraction structure. For each extraction structure of the at least one extraction structure, moving between the adsorption configuration and the desorption configuration may include the extraction structure moving into and out of the enclosure. The thermal liquid may be circulating in a closed circuit. Theheat source may be solar thermal. The heat source may be waste heat. The heat source may be electric. The heat source may be geothermal. The at least one extraction structure may be two extraction structures. When one extraction structure is in the adsorption configuration, the other extraction structure may be in the desorption configuration. The at least one extraction structure may include at least one bed comprising the desiccant material. The at least one extraction structure may include a plurality of beds, each having the desiccant material and coupled to at least one other bed. For each extraction structure of the at least one extraction structure, the adsorption configuration may include the extraction structure extended vertically with the beds spread apart and exposed to the atmosphere, and the desorption configuration may include the extraction structure retracted with the beds lowered into an enclosure such that the desiccant material is isolated from the atmosphere. The first portion may be also the second portion. The cooling surface may be cooled by the airflow. The system may further include a collecting tank. The condensing chamber may be configured to store the liquid water in the collecting tank. The cooling surface may be cooled by liquid water taken from the collecting tank. The heating subsystem may include a liquid-air heat exchanger and a fan. For each extraction structure of the at least one extraction structure, the desorption configuration may include at least the second portion of the desiccant material being in thermal communication with the thermal liquid via a forced airflow blown by the fan through the liquid-air heat exchanger. The at least one extraction structure may include a substrate to which the desiccant material may be coupled. The desiccant material may be a solid phase desiccant material. The substrate may include at least one lumen, with the at least one lumen in fluidic contact with the heating subsystem. For each extraction structure of the at least one extraction structure, the desorption configuration may also include at least the second portion of the desiccant material in thermal communication with the thermal liquid through the substrate, with the thermal liquid passing through the at least one lumen of the substrate. The desiccant material may be a coating on the substrate. The substrate may include a plurality of hollow fibers. The at least one extraction structure may be a rotary desiccant that is rotatably coupled to an axle and operatively coupled to an actuator. The desiccant material may be divided into the first portion and the second portion, with the first portion and the second portion changing location on the extraction structure as it rotates such that the first portion may be always in at least a partially unsaturated state and the second portion may be always in at least a partially saturated state. As the extraction structure rotates it may be continuously in the adsorption configuration and the desorption configuration, with the thermal liquid continuously heating the second portion to at least the release temperature, and with the first portion continuously in fluidic contact withthe airflow comprising atmospheric water. The airflow may be a passive airflow. The release temperature may be less than 100 °C. The desiccant material may include silica gel.

[0012] According to another aspect of the disclosure, a system for atmospheric water extraction includes at least one extraction structure, each extraction structure having a desiccant material. Each extraction structure is movable between an adsorption configuration and a desorption configuration. The system also includes a condensing chamber coupled to and in fluidic communication with the at least one extraction structure, the condensing chamber having a cooling surface and configured to receive a water vapor from the at least one extraction structure and condense the water vapor into liquid water on the cooling surface. Additionally, the system includes a heating subsystem that is thermal liquid-based. The heating subsystem is coupled to the extraction structure and has a thermal liquid in thermal contact with a heat source. For each extraction structure of the at least one extraction structure, the adsorption configuration includes the extraction structure being exposed to an atmosphere such that the desiccant material of the extraction structure is in fluidic contact with an airflow having atmospheric water. For each extraction structure of the at least one extraction structure, the desorption configuration includes the desiccant material of the extraction structure being in fluidic communication with the cooling surface of the condensing chamber. The desorption configuration also includes the desiccant material in thermal communication with the thermal liquid such that the desiccant material is heated to at least a release temperature, causing the desiccant material to release adsorbed atmospheric water as water vapor.

[0013] Particular embodiments may comprise one or more of the following features. The system may further include an enclosure for each extraction structure of the at least one extraction structure. For each extraction structure of the at least one extraction structure, the desorption configuration may also include the extraction structure being enclosed inside the enclosure, isolated from the atmosphere. The desiccant material of the at least one extraction structure may remain stationary when the extraction structure moves between the adsorption configuration and the desorption configuration. The system may further include an enclosure for each extraction structure of the at least one extraction structure. For each extraction structure of the at least one extraction structure, moving between the adsorption configuration and the desorption configuration may include the extraction structure moving into and out of an enclosure. The thermal liquid may be circulating in a closed circuit. The heat source may be solar thermal. The heat source may be waste heat. The heat source may be electric. The heat source may be geothermal. The at least one extraction structure may be two extraction structures. When one extraction structure is in the adsorption configuration, theother extraction structure may be in the desorption configuration. The at least one extraction structure may include at least one bed comprising the desiccant material. The at least one extraction structure may include a plurality of beds, each comprising the desiccant material and coupled to at least one other bed. For each extraction structure of the at least one extraction structure, the adsorption configuration may include the extraction structure extended vertically with the beds spread apart and exposed to the atmosphere. The desorption configuration may include the extraction structure retracted with the beds lowered into an enclosure such that the desiccant material is isolated from the atmosphere. The cooling surface may be cooled by the airflow. The system may further include a collecting tank. The condensing chamber may be configured to store the liquid water in the collecting tank. The cooling surface may be cooled by liquid water taken from the collecting tank. The heating subsystem may include a liquidair heat exchanger and a fan. For each extraction structure of the at least one extraction structure, the desorption configuration may include the desiccant material being in thermal communication with the thermal liquid via a forced airflow blown by the fan through the liquidair heat exchanger. The at least one extraction structure may include a substrate to which the desiccant material may be coupled, the desiccant material being a solid phase desiccant material. The substrate may include at least one lumen, with the at least one lumen in fluidic contact with the heating subsystem. For each extraction structure of the at least one extraction structure, the desorption configuration may also include the desiccant material in thermal communication with the thermal liquid through the substrate, with the thermal liquid passing through the at least one lumen of the substrate. The desiccant material may be a coating on the substrate. The substrate may include a plurality of hollow fibers. The airflow may be a passive airflow. The release temperature may be less than 100 °C. The desiccant material may include silica gel.

[0014] According to yet another aspect of the disclosure, a method for extracting atmospheric water includes exposing an extraction structure having a desiccant material to an atmosphere such that the desiccant material is in fluidic contact with an airflow having atmospheric water, the desiccant material being coupled to a substrate having at least one lumen. The method also includes placing a thermal liquid of a heating subsystem in thermal contact with a heat source. The heating subsystem is thermal liquid-based, coupled to the extraction structure, and in fluidic contact with the at least one lumen. The method further includes placing the desiccant material of the extraction structure in thermal communication with the thermal liquid through the substrate, by passing the thermal liquid through the at least one lumen such that the desiccant material is heated to at least a release temperature, causingthe desiccant material to release adsorbed atmospheric water as a water vapor. Finally, the method includes condensing the water vapor into liquid water on a cooling surface of a condensing chamber coupled to and in fluidic communication with the extraction structure.

[0015] Particular embodiments may comprise one or more of the following features. The method may further include enclosing the extraction structure inside an enclosure, isolating the extraction structure from the atmosphere, before placing the desiccant material in thermal communication with the thermal liquid. Enclosing the extraction structure inside the enclosure may include closing the enclosure while the desiccant material remains stationary. Enclosing the extraction structure inside the enclosure may include the extraction structure moving into and out of the enclosure. The method may further include circulating the thermal liquid in a closed circuit. The heat source may be solar thermal. The heat source may be waste heat. The heat source may be electric. The heat source may be geothermal. The method may further include exposing another extraction structure also including the desiccant material to the atmosphere such that the desiccant material may be in fluidic contact with the airflow with atmospheric water, both extraction structures coupled to the condensing chamber and the heating subsystem. While one extraction structure is being exposed to the atmosphere, the desiccant material of the other extraction structure may be in thermal communication with the thermal liquid. The extraction structure may include a plurality of beds, each bed having the desiccant material and coupled to at least one other bed. Exposing the extraction structure to the atmosphere may include extending the extraction structure vertically with the plurality of beds spread apart, exposing the desiccant material to the atmosphere. The method may further include cooling the cooling surface with the airflow. The method may further include storing the liquid water in a collecting tank coupled to, and in fluidic communication with, the condensing chamber. The method may further include cooling the cooling surface with liquid water taken from the collecting tank. The desiccant material may be a coating on the substrate. The substrate may be a plurality of hollow fibers. The airflow may be a passive airflow. The release temperature may be less than 200 °C. The desiccant material may include silica gel.

[0016] Aspects and applications of the disclosure presented here are described below in the drawings and detailed description. Unless specifically noted, it is intended that the words and phrases in the specification and the claims be given their plain, ordinary, and accustomed meaning to those of ordinary skill in the applicable arts. The inventors are fully aware that they can be their own lexicographers if desired. The inventors expressly elect, as their own lexicographers, to use only the plain and ordinary meaning of terms in the specification and claims unless they clearly state otherwise and then further, expressly set forththe “special” definition of that term and explain how it differs from the plain and ordinary meaning. Absent such clear statements of intent to apply a “special” definition, it is the inventors’ intent and desire that the simple, plain and ordinary meaning to the terms be applied to the interpretation of the specification and claims.

[0017] The inventors are also aware of the normal precepts of English grammar. Thus, if a noun, term, or phrase is intended to be further characterized, specified, or narrowed in some way, then such noun, term, or phrase will expressly include additional adjectives, descriptive terms, or other modifiers in accordance with the normal precepts of English grammar. Absent the use of such adjectives, descriptive terms, or modifiers, it is the intent that such nouns, terms, or phrases be given their plain, and ordinary English meaning to those skilled in the applicable arts as set forth above.

[0018] Further, the inventors are fully informed of the standards and application of the special provisions of 35 U.S.C. § 112(f). Thus, the use of the words “function,” “means” or “step” in the Detailed Description or Description of the Drawings or claims is not intended to somehow indicate a desire to invoke the special provisions of 35 U.S.C. § 112(f), to define the invention. To the contrary, if the provisions of 35 U.S.C. § 112(f) are sought to be invoked to define the inventions, the claims will specifically and expressly state the exact phrases “means for” or “step for”, and will also recite the word “function” (i.e., will state “means for performing the function of [insert function]”), without also reciting in such phrases any structure, material or act in support of the function. Thus, even when the claims recite a “means for performing the function of . . . “ or “step for performing the function of . . . ,” if the claims also recite any structure, material or acts in support of that means or step, or that perform the recited function, then it is the clear intention of the inventors not to invoke the provisions of 35 U.S.C. § 112(f). Moreover, even if the provisions of 35 U.S.C. § 112(f) are invoked to define the claimed aspects, it is intended that these aspects not be limited only to the specific structure, material or acts that are described in the preferred embodiments, but in addition, include any and all structures, materials or acts that perform the claimed function as described in alternative embodiments or forms of the disclosure, or that are well known present or later-developed, equivalent structures, material or acts for performing the claimed function.

[0019] The foregoing and other aspects, features, and advantages will be apparent to those artisans of ordinary skill in the art from the DESCRIPTION and DRAWINGS, and from the CLAIMS.BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The disclosure will hereinafter be described in conjunction with the appended drawings, where like designations denote like elements, and:

[0022] FIGs. 1A, IB, and 1C are perspective, top, and cross-sectional views of an atmospheric water extraction (AWE) system, respectively;

[0023] FIG. 2 is a schematic view of another embodiment of the AWE system, having a rotating desiccant wheel;

[0024] FIGs. 3 A and 3B are perspective views of two embodiments of an extraction structure of an AWE system;

[0025] FIG. 4A shows a polymeric hollow fiber heat exchanger;

[0026] FIGs. 4B - 4D are perspective views of different embodiments of a hollow fiber-based extraction structure of an AWE system; and

[0027] FIG. 5 is a process flow for a method for atmospheric water extraction.DETAILED DESCRIPTION

[0028] This disclosure, its aspects and implementations, are not limited to the specific material types, components, methods, or other examples disclosed herein. Many additional material types, components, methods, and procedures known in the art are contemplated for use with particular implementations from this disclosure. Accordingly, for example, although particular implementations are disclosed, such implementations and implementing components may comprise any components, models, types, materials, versions, quantities, and / or the like as is known in the art for such systems and implementing components, consistent with the intended operation.

[0029] The word "exemplary," "example," or various forms thereof are used herein to mean serving as an example, instance, or illustration. Any aspect or design described herein as "exemplary" or as an “example” is not necessarily to be construed as preferred or advantageous over other aspects or designs. Furthermore, examples are provided solely for purposes of clarity and understanding and are not meant to limit or restrict the disclosed subject matter or relevant portions of this disclosure in any manner. It is to be appreciated that a myriad of additional or alternate examples of varying scope could have been presented, but have been omitted for purposes of brevity.

[0030] While this disclosure includes a number of embodiments in many different forms, there is shown in the drawings and will herein be described in detail particular embodiments with the understanding that the present disclosure is to be considered as an exemplification of the principles of the disclosed methods and systems, and is not intended to limit the broad aspect of the disclosed concepts to the embodiments illustrated.

[0031] There is a finite amount of fresh water for human consumption, industrial use, and agriculture. Many communities in arid regions of the world are limited and often rely upon large infrastructure projects to move and import water long distances from oceans or sources of freshwater to meet current and growing water supplies. These infrastructure projects have high capital plus operating costs, and impact lands through which pipelines or canals transect. However, there is a large amount of water available in the air, an enormous volume that could be tapped into by those water-deprived and isolated locations without large-scale pipeline or canal infrastructure projects.

[0032] Another reason for the growing interest in atmospheric water extraction (AWE) technology is that the water extracted from the air is very pure, making this process ideal for many industrial or other water applications.

[0033] Removing water vapor in the atmosphere, or water dehumidification, is widely practiced at both the industrial and household level. However, these conventional systems require a significant amount of electrical energy for their operation (e.g., for heating, etc.). The current, commercial dehumidification devices on the market can be divided into two major categories: compressor-based and desiccant-based. A compressor-based system captures water vapor from the ambient air and condensates it to liquid water at its dew point temperature by exposing it to a cold surface that is typically cooled using a refrigerant-based cooling system. In contrast, a desiccant-based system extracts moisture from the ambient air through sorption, utilizing porous desiccant materials.

[0034] The desiccant-based system is attractive for several reasons. Desiccantbased systems have more reliable performance across a wider range of ambient air temperatures (e.g., 1-40 °C) and relative humidity (RH) conditions (e.g., 10 - 100% RH) than compressorbased systems. This makes desiccant-based systems more energy efficient at optimal conditions (e.g., above 25 °C and below 60% RH). Additionally, a desiccant-based device typically produces water of a higher quality than a compressor-based system. Compressorbased systems condense and produce liquid-water on cold surfaces, which unfortunately also separates particulates and volatile compounds from the air and into the water. Furthermore, the desiccant-based system does not use an energy-intensive refrigerant compressor and is more environmentally friendly for lower RH environments.

[0035] Although they are more energy efficient than compressor-based systems at low RH, conventional desiccant-based systems still require considerable energy, which can limit the utility of such a device. Various modes of operation (e.g., active, passive, etc.) exist for desiccant-based systems. Active mode systems use energy to operate fans (or blowers) that move air containing moisture across or through solid phase desiccants. Passive modes operate without fans and rely upon diffusion or wind to transport water vapor to the solid-phase desiccants. Currently, the current limiting factor for AWE by desiccants is the energy required to operate electric-powered heaters used to desorb captured water from the solid phase desiccant. Much more energy is required for this heating than to operate fans.

[0036] As a specific example, it theoretically takes 2,200-2,700 kJ of heat to evaporate 1kg of water (or about 0.7 kWh / L). However, the energy consumption for the dehumidification process and for desiccant regeneration would be much greater, roughly an additional 0.3 to 0.5 kWh / L. The heat in the desiccant system creates a difference in partial pressure of the water vapor, which drives the desorption process from the desiccator. The subsequently released hot, humid air is then condensed by ambient cool air.

[0037] Contemplated herein is a system and method for atmospheric water extraction (AWE) which combines desiccant materials to adsorb atmospheric water with a heating subsystem to desorb the water using superheated liquids, rather than solar (PV) or electric-generated radiant heat.

[0038] The use of a thermal liquid-based heating subsystem opens up additional heat sources, beyond the electric heating of conventional extraction systems. According to various embodiments, the heated liquids can be produced through various methods including, but not limited to, solar hot-water systems (e.g., evacuated tubes, solar collector, parabolic solar concentrator, etc.), geothermal sources, and / or waste-heat from combustion or mechanical devices utilized for other applications (e.g., energy production, heating or cooling systems, transportation, etc.). Additionally, some desiccants only need to be heated to above 40 °C to desorb water vapor, expanding the potential heat sources even further.

[0039] According to various embodiments, the thermal liquid may be water that, alone or in combination with other solutions (e.g., ethylene glycol, etc.) has unique heat adsorbing properties. Alone or in combination with the other heating sources mentioned above, solar hot-water systems dramatically reduce the electric power needed for operation. In some embodiments, electricity is only needed to operate fans that move air.

[0040] Replacing the conventional electric radiative heater with thermal liquid systems substantially reduces the overall energy needs, making the system more sustainable while also producing high-quality potable water at a much lower operating cost than possible with conventional water extraction systems.

[0041] The contemplated AWE system's novel thermal liquid-based heating subsystem also improves how the heat is delivered to the desiccant material to desorb the extracted atmospheric water. Conventional systems drive water off desiccant material (often in the form of a rotary desiccant wheel) by passing hot air over the desiccant material. This can result in significant heat loss, as air is a good insulator, reducing the conventional systems heat transfer ability.

[0042] In some embodiments, instead of blowing hot air towards and over the desiccant materials, the AWE system contemplated herein passes hot fluid through one or more conduits (e.g., the lumen of hollow fibers, etc.) that are in direct contact with the desiccant material (e.g., the desiccant material is coated on the outside of the hollow fibers, etc.). In some embodiments, conduits coated, encased, or otherwise in thermal contact with the desiccant material may be assembled into discrete desiccant heat exchanger (HX) units. These units are advantageous over the architectures common to traditional water extraction devices,which often comprise a rotary desiccant wheel. Unlike the rotary wheel, multiple HX units could be added in a small footprint as each unit is individually heated.

[0043] According to various embodiments, the contemplated AWE system is more efficient in energy use, with faster adsorption and desorption kinetics and higher operation cycles in extracting and producing water due to its unique design than conventional water extraction systems. This is due, at least in part, to having a lower regeneration temperature, a smaller footprint, being modular, incurring lower heat loss, and having high conductance, according to various embodiments.

[0044] The AWE system contemplated herein focuses on stationary (non-mobile) sources of water production for industrial application needing high-quality water (e.g., computer chip applications, beverage make-up water, food production, etc.). These applications conventionally utilize tap water, groundwater, or recycled water, which must then be demineralized (e.g., softening, complete desalination, etc.), filtered, and stripped of organic compounds through adsorption or oxidation, before it can be used. The contemplated system avoids these burdens by extracting high-quality water directly from the atmosphere.

[0045] It should be noted that while much of this disclosure is done in the context of a stationary source of water production for industrial application, other embodiments may be adapted for other purposes. For example, some embodiments of the AWE system are adapted for mobility, able to be quickly deployed on a temporary basis to address a sudden need for clean water. Other embodiments may be adapted for other purposes including, but not limited to, agriculture (e.g., outdoor or hydroponic) and domestic drinking water. Those skilled in the art will recognize that the contemplated AWE system may be adapted for other uses as well.

[0046] FIGs. 1A, IB, and 1C are perspective, top, and cross-sectional views of a non-limiting example of an atmospheric water extraction (AWE) system 100, respectively. Due, at least in part, to the thermal liquid-based heating subsystem 116 used to desorb captured atmospheric water from a desiccant material 104, this AWE system 100 is able to operate with greater efficiency and with greater versatility than conventional water extraction technologies. As shown, the AWE system 100 comprises at least one extraction structure 102, a condensing chamber 106, and a heating subsystem 116, according to various embodiments. Each will be discussed in turn.

[0047] In the context of the present description and the claims that follow, an extraction structure 102 is a structure or framework comprising one or more desiccant materials 104, giving them form and stability. Put differently, the extraction structure 102 is made up ofa support structure and at least one desiccant material 104, with the support structure configured to protect the desiccant material 104 and arrange the desiccant material 104 such that is can adsorb atmospheric water 134 when the extraction structure 102 is exposed to the atmosphere 126 and the desiccant material 104 is put in fluidic contact with an airflow 132 (e.g., natural wind or air current, forced airflow 138 from a fan 148, etc.) comprising atmospheric water 134. It should be noted that other embodiments may be adapted for exposure to water-rich gases that are not atmospheric, such as the waste or exhaust from some industrial processes.

[0048] An extraction structure 102 may comprise a variety of materials, in addition to one or more desiccant materials 104. According to various embodiments, an extraction structure 102 may have strong elements for structural support (e.g. metal, plastic, wood, etc.), and may also include more delicate elements meant to attach to, and give form to, one or more desiccant materials 104. Examples include, but are not limited to, mesh, fabric, paper, foils, sponge-like materials, glass, plastic, and the like. In some embodiments, the extraction structure 102 may comprise a support structure that is releasably coupled to the desiccant material 104, such that the replacement of the desiccant material 104 is facilitated. As an option, some parts of the support structure may be disposable (e.g., a disposable 3D-printed interface to hold the desiccant material 104 and releasably couple with the rest of the extraction structure 102, etc.)

[0049] It should be noted that, for simplicity, the various non-limiting examples of extraction structures 102 discussed and shown herein will only have one desiccant material 104. However, in other embodiments, each extraction structure 102 may have one, two, or many different desiccant materials 104, which may be advantageous in certain use cases. For example, in one embodiment, an extraction structure 102 may comprise multiple desiccant materials 104, each being optimized for a particular use environment (e.g., a particular RH range, a particular temperature range, etc.). Combining different desiccant materials 104 may make the AWE system 100 able to operate across a wider range of environmental conditions without requiring that the desiccant material(s) 104 be changed.

[0050] The extraction structure 102 comprises at least one desiccant material 104. In the context of the present description and the claims that follow, a desiccant material 104 will remove moisture (e.g., atmospheric water 134) from its environment (e.g., the atmosphere 126) primarily through adsorption, a surface phenomenon. This captured water will be desorbed when the desiccant material 104 is heated to at least a release temperature 140, which varies with the desiccant material 104. The release temperature 140 may also be referred to asa regeneration temperature, as this desorption process will regenerate the desiccant material 104, preparing it for another cycle of capture and release.

[0051] It should be noted that while there are some desiccant materials 104 that also involve other processes like absorption, and that have release processes that are not purely driven by temperature, the AWE system 100 contemplated herein will be discussed in the context of desiccant materials 104 adsorbing water and desorbing that water when heated to at least a release temperature 140. However, those skilled in the art will recognize that the contemplated AWE system 100 and method may be adapted for use with other desiccant materials 104 making use of other regeneration processes. Furthermore, the AWE system 100 and method may also be adapted for use in the extraction of other substances from the atmosphere, using other sorbent materials while still making use of the advantages provided by the novel thermal liquid-based heating subsystem 116.

[0052] According to various embodiments, the desiccant material 104 may comprise a range of materials including, but not limited to, activated alumina, silica gels, zeolite, MOF (metal-organic frameworks), and the like. Zeolite as an adsorbent can sorb about 0.25 grams of water vapor 112 per gram of material at 20-100% RH. For RH 0-20%, sorption capacity logarithmically increases from 0.0 to 0.25 g / g. As such, the productivity of desiccantbased dehumidifiers should be roughly the same once the relative humidity is above 20%, and should decrease as the relative humidity falls below 20%.

[0053] The choice of desiccant material 104 will determine the release temperature 140 that will need to be attained in order to desorb the extracted water. As previously discussed, the energy budget of these water extraction devices is dominated by the cost of heating the desiccant material 104 to reclaim the water. Thus, the release temperature 140 is an important characteristic to consider when choosing a desiccant material 104 and designing an AWE device. Some materials may have a great capacity for water capture but would require too much energy to later release it. This high energy cost limits what heat sources can be used. Other materials may have lower release temperatures 140, but may have low capacity requiring more capture / release cycles to extract the same amount of water 114, or may be less durable.

[0054] The contemplated AWE system 100 is advantageous over conventional systems for a number of reasons, but one of the biggest reasons is that it can operate with great energy efficiency. According to various embodiments, the AWE system 100 has eliminated some of the energy lost or misspent by conventional systems. Most conventional systems use a zeolite-based desiccant coated on a regenerable rotary wheel substrate. In these conventional systems, hot air is passed over the desiccant material 104 to drive off water which is thencondensed as liquid water 114. Blowing hot air towards and over the desiccant materials 104 in a traditional system can result in significant heat loss. Air is a good insulator, and will reduce its heat transfer ability, making the traditional systems less efficient.

[0055] That inefficiency inherent to traditional designs gets much worse as the scale increases. Conventional commercial home desiccant dehumidifiers report productivity of 7- 10 L / day (at 20°C and -60% RH) using 1.8-2.0 kWh / L, equating to roughly $0.10-0.30 per liter of water (excluding treatment cost). However, a scaled-up version of this system for a larger commercial, outdoor application to produce a larger amount of liquid water 114 would translate into a substantial electrical energy need that could be difficult or very expensive to meet. Industrial water users in arid regions currently pay in excess of $0.60 per liter of high- purity water.

[0056] According to various embodiments, the AWE system 100 and method take a different approach, using desiccant materials 104 that have a lower release temperature 140 and regenerating them with a thermal liquid-based heating subsystem 116 that is able to deliver the heat to the desiccant material 104 with greater efficiency, lower heat loss, and using a more cost effective heat source 120, according to various embodiments. Using a desiccant material 104 having a low release temperature 140 opens up the chance to use low-grade heat sources that have been ignored by traditional systems because they wouldn't result in sufficient heat for release.

[0057] According to various embodiments, the desiccant material 104 and type (e.g., silica gel, zeolite, metal-organic frameworks, etc.) may be selected such that the release temperature 140 is low to moderate, permitting the use of solar energy or other low-grade heat sources for desorbing the captured water and regenerating the desiccant material 104. In some embodiments, the release temperature 140 of the desiccant material 104 is less than 150 °C, which is lower than most zeolite regeneration temperatures. In other embodiments, the release temperature 140 may be less than 100 °C, while in still other embodiments the release temperature 140 may be less than 80 °C, or even 70 °C. These low release temperatures 140 permit the use of low-grade heat sources 120, which will be discussed further, below.

[0058] Just as desiccant materials 104 can be in a variety of forms (e.g., bulk solids, thin coatings, powders, beads, granules, pellets, sheets, composite materials, honeycomb structures, etc.), the support structures used to hold them can take many forms. In some embodiments, the extraction structure 102 may comprise one or more beds 152, each comprising a desiccant material 104. In the context of the present description and the claims that follow, a bed 152 is container of some sort that holds the desiccant material 104, giving itform (in the case of formless materials like beads, granules, and powders) while also allowing exposure to local airflow 132. In other words, a bed 152 is a vessel for a desiccant material 104 that permits an airflow 132 to enter / pass through while containing the desiccant material 104. A non-limiting example of a bed 152 will be discussed in greater detail with respect to FIG. 3A, below.

[0059] In some embodiments, an extraction structure 102 may comprise a single bed 152. In other embodiments, including the non-limiting example shown in FIGs. 1A-1C, an extraction structure 102 may comprise a plurality of beds 152, each comprising a desiccant material 104. In some multi -bed embodiments, the beds 152 may operate independent of each other. In other embodiments, the plurality of beds 152 may operate as a group. In some multibed embodiments, each bed 152 may be coupled, in some way, to at least one other bed 152. For example, in some embodiments, the beds 152 may be coupled to share a resource (e.g., in fluidic communication so a thermal liquid 118 may be shared among the beds 152 from a single source, able to release liquid water 114 to a shared collector during regeneration, etc.).

[0060] In some embodiments, the beds 152 may be coupled to move together, or to maintain a position or distance relative to each other. According to various embodiments, an extraction structure 102 is movable to different configurations. In the context of the present description and the claims that follow, a configuration defines a position / orientation / arrangement of the extraction structure 102 relative to other elements of the AWE system 100, thereby granting or denying access to resources such as the heating subsystem 116, the atmosphere 126, the condensing chamber 106, and the like. In some embodiments, moving the extraction structure 102 from one configuration to another may involve moving the extraction structure 102. In other embodiments, such a transition may instead involve movement or utilization of other aspects of the AWE system 100 (e.g., vents, valves, doors, fans, etc.) while the extraction structure 102 remains stationary. The different configurations of the extraction structure 102 within the AWE system 100 (e.g., the adsorption configuration 122, the desorption configuration 124, etc.) and how the extraction structure 102 can move from one configuration to another will be discussed further, below.

[0061] Embodiments where the extraction structure 102, or parts of the extraction structure 102, moves when transitioning between configurations have an opportunity for further improvement in efficiency. Depending on the nature of the AWE system 100, the needs of the extraction structure 102 to accomplish a task related to a particular configuration (e.g., adsorbing atmospheric water 134, desorbing captured water, etc.) may vary between configurations. As a specific example, the main purpose of an adsorption configuration 122would be to expose the desiccant material 104 of the extraction structure 102 to airflows 132 containing atmospheric water 134. Thus, for a multi -bed embodiment such a configuration would benefit from spacing the beds 152 apart to minimize one bed 152 from inhibiting an airflow 132 to another (e.g., if the beds 152 are too close, some may not receive as much exposure as others). However, the main purpose of a desorption configuration 124 would be to desorb captured water into water vapor 112 which can then be sent to the condensing chamber 106. This desorption, accomplished through the introduction of heat to the desiccant material 104, would be benefitted by putting the extraction structure 102 in a small enclosure. Reducing the volume of the enclosure will make better use of the heat being provided by the heating subsystem 116 (i.e., through the thermal liquid 118). In embodiments where transitioning between configurations involves moving parts of the extraction structure 102 itself, both of these beneficial arrangements may be utilized as part of the capture / release cycle.

[0062] As a specific, non -limiting example, see the AWE system 100 shown in FIGs. 1A-1C. Each of the two extraction structures 102 comprise multiple disk shaped beds 152 stacked in vertical columns, each bed 152 holding a desiccant material 104 and coupled to at least one other bed 152 in the stack. According to various embodiments, these extraction structures 102 are each configured to have an adsorption configuration 122 where the extraction structure 102 is extended vertically with the beds 152 spread apart and exposed to the atmosphere 126 (i.e., the left extraction structure 102 of FIG. 1A), and a desorption configuration 124 where the extraction structure 102 is retracted with the beds 152 lowered into an enclosure 154 such that the desiccant material 104 is isolated from the atmosphere 126 (i.e., the right extraction structure 102 of FIG. 1 A). In contrast to traditional AWE devices that use rotating wheels, the ability of some parts of an extraction structure 102 in some embodiments of the contemplated AWE system 100 to rearrange themselves relative to each other and / or relative to other elements of the AWE system 100 facilitates efficient oppression in all parts of the capture / release cycle, not just one.

[0063] Unlike traditional desiccant-based water extraction systems, the contemplated AWE system 100 uses a thermal liquid-based heating subsystem 116. In the context of the present description and the claims that follow, a thermal liquid-based heating subsystem 116 is a system that uses a liquid (i.e., thermal liquid 118) as the medium to transfer heat from a heat source 120 to the desired location. The contemplated thermal liquid-based heating subsystem 116 is particularly well adapted for providing direct heat to the desiccant material 104 of an extraction structure 102, in the place of conventional electric coil heaters.

[0064] The thermal liquid 118 (e.g., water, ethylene glycol, a combination of both, etc.) may be heated by the heating subsystem 116 using a wide variety of heat sources 120. In some embodiments, the heating subsystem 116 may comprise a pump 150, and the thermal liquid 118 may be circulated in a closed circuit 146 through conduits (e.g., pipes, tubes, lumens, hollow fibers, etc.), and also passing through radiators, heat exchangers, and other heat distribution devices. Thermal liquid-based heating offers efficient heat transfer and temperature control.

[0065] The heating subsystem 116 transfers heat from a heat source 120 to the thermal liquid 118. The thermal liquid 118 is in thermal communication (i.e., heat can pass between them but direct contact is not required; heat transfer can occur via conduction, convection, or radiation) with the heat source 120 via the heating subsystem 116, at least intermittently. In some embodiments, the thermal liquid 118 and the heat source 120 are in thermal contact (i.e., heat transferred between them through direct contact, primarily through conduction).

[0066] According to various embodiments, the heating subsystem 116 is coupled to the at least one extraction structure 102. In some embodiments, the nature of that coupling is more substantial than in others. For example, in some embodiments the thermal liquid 118 is in thermal communication with the desiccant material 104 of the extraction structure 102. As a specific example, in one embodiment, heat from the thermal liquid 118 is communicated to the desiccant material 104 via a forced airflow 138 from a fan 148 passing through a liquidair heat exchanger such that the heated air passes over and through the desiccant material 104 (see FIG. 2). In other embodiments, however, the thermal liquid 118 may be in thermal contact with the extraction structure 102, or even with the desiccant material 104 specifically. The interface between thermal liquid 118 and the desiccant material 104 will be discussed in greater detail with respect to FIGs. 3 A-4D, below.

[0067] As a specific, non-limiting example, in one embodiment the heating subsystem 116 pumps the thermal liquid 118 through a closed circuit 146 that passes through a solar-thermal device (e.g., a modified manifold of evacuated tubes, solar collectors, parabolic concentrator, etc.). That circuit can be connected, by operating a valve, to a larger circuit that also passes through the extraction structure 102 where heat is communicated to the desiccant material 104 during regeneration / desorption operations. As an option, the heating subsystem 116 may comprise some form of computing device, such as a microcontroller, to operate various aspects such as valves based on inputs from sensors and / or users, or by following a predefined sequence of instructions and timings. Those with skill in the art will recognize thatvarious aspects of the AWE system 100 disclosed herein may be automated using various techniques known in the art.

[0068] One of the advantages of utilizing desiccant materials 104 having release temperatures 140 lower than those required by traditional desiccant-based dehumidifier devices is that it facilitates the use of a low-grade (e.g., below 150 °C) heat source 120. Exemplary heat sources 120 include, but are not limited to, solar thermal (e.g., a set of evacuated tubes, a solar collector, a parabolic solar concentrator, solar ponds, flat-plate collectors, etc.), geothermal (e.g., ground source heat pumps, geothermal wells, etc.), waste heat (e.g., manufacturing, electronics, data centers, boilers, HVAC systems, flue gases from power plants, heat from industrial ovens, etc.), and renewable electric (e.g., wind, solar photovoltaic, thermoelectric, etc.). In some embodiments, electricity may be used only to drive some electric devices such as a fan / blower, microcontrollers or other programmable control devices, sensors, and other ancillary systems.

[0069] The condensing chamber 106 is responsible for turning the water vapor 112 released from the desiccant material 104 into liquid water 114, in some embodiments. In other embodiments, the water vapor 112 obtained from the desiccant material 104 may be treated as an output itself, and used for some downstream purpose. According to various embodiments, including the non-limiting example shown in FIGs. 1A-1C, the condensing chamber 106 may be coupled to and in fluidic communication with the at least one extraction structure 102.

[0070] The conduit 308 is configured to receive warm water vapor 112 from the extraction structure(s) 102 and condense it into liquid water 114 by introducing it to a cooling surface 110 (i.e., a surface within the condensing chamber 106 having a depressed temperature that is cold enough to result in condensation). According to various embodiments, the desorbed moist air will go through the condensing chamber 106, where the water vapor 112 will condense into water droplets upon interaction with the cooling surface 110. In some embodiments, the liquid water 114 condensed by the cooling surface 110 may be collected in a collecting tank 108. The water quality from this system 100 is typically higher than that of other systems.

[0071] In some embodiments, the cooling surface 110 may be cooled by an airflow 132 (e.g., ambient wind). In other embodiments, the cooling surface 110 may be cooled using liquid water 114 that is pumped from the collecting tank 108. In still other embodiments, other methods may be used to lower the temperature of the cooling surface 110 enough to condense the desorbed water vapor 112 into liquid water 114, including but not limited to Peltier devices and cryogenic fluids (e.g., liquid carbon dioxide captured and compressed as part of a carboncapture effort at a manufacturing plant that is also using the AWE system 100 to produce pure water, etc.).

[0072] As previously discussed, in some embodiments an extraction structure 102 is movable into, or between, different configurations. According to various embodiments, each extraction structure 102 of the contemplated AWE system 100 has an adsorption configuration 122 and a desorption configuration 124. In some embodiments, an extraction structure 102 may have additional configurations. Furthermore, in some embodiments an extraction structure 102 may be able to be in more than one configuration at the same time (e.g., the AWE system 100 of FIG. 2 can be in the adsorption configuration 122 and the desorption configuration 124 simultaneously), while in other embodiments the extraction structure 102 may be limited to one configuration at a time. This will depend on the architecture of the system 100, as well as how the configurations are defined.

[0073] As stated before, in the context of the present description and the claims that follow, a configuration defines a position / orientation / arrangement of the extraction structure 102 relative to other elements of the AWE system 100, thereby granting or denying access to resources such as the heating subsystem 116, the atmosphere 126, the condensing chamber 106, and the like. For clarity, it can also be said that a configuration is associated with a purpose or goal that may only be accomplished with an extraction structure 102 if that extraction structure 102 is in the associated configuration. This concept can be explored further in a more detailed discussion of the adsorption configuration 122 and the desorption configuration 124 that are inherent to every extraction structure 102 of the contemplated AWE system 100.

[0074] Furthermore, moving the extraction structure 102 from one configuration to another may involve moving the extraction structure 102, or part of the extraction structure 102, according to some embodiments. In other embodiments, such a transition may instead involve movement or utilization of other aspects of the AWE system 100 (e.g., vents, valves, doors, fans, etc.) while the extraction structure 102 remains stationary. Both approaches have advantages and disadvantages, which will be discussed.

[0075] The adsorption configuration 122 is the configuration assumed by the extraction structure 102 when it is capturing atmospheric water 134. More specifically, the adsorption configuration 122 of an extraction structure 102 comprises the extraction structure 102 being exposed to the atmosphere 126 such that at least a first portion 128 of the desiccant material 104 of that extraction structure 102 is in fluidic contact with an airflow 132 comprising atmospheric water 134, according to various embodiments. In some embodiments that airflow 132 may be a passive airflow 136, while in other embodiments it may be forced (e.g., drivenby a fan or blower, etc.). While in the adsorption configuration 122, water vapor 112 adsorbs to the desiccant material 104 at ambient temperature, according to various embodiments.

[0076] It should be noted that while the adsorption configuration 122 only requires a part (i.e., the first portion 128) of the desiccant material 104 be in fluidic contact with the airflow 132, in some embodiments the adsorption configuration 122 may include the entirety of the desiccant material 104 being in fluidic contact with the airflow 132. See, for example, the embodiment shown in FIGs. 1 A-1C. As will be discussed in the context of the wheel-based embodiment of the AWE system 100, shown in FIG. 2, in some embodiments an extraction structure 102 may be able to be in two configurations at the same time. That discussion will be facilitated by this partitioning of the desiccant material 104.

[0077] According to various embodiments, the adsorption configuration 122 of an extraction structure 102 comprises at least a first portion 128 of the desiccant material 104 being exposed to an airflow 132 comprising water 114, such as atmospheric water 134. In some embodiments, the airflow 132 may be a passive airflow 136 (e.g., wind). An advantage of using passive airflows 136 is that it reduces the overall energy requirement for operation. However, natural passive airflow 136 can be intermittent and unpredictable.

[0078] In other embodiments, the airflow 132 may be a forced airflow 138 (e.g. driven by a fan 148 or a blower, part of an exhaust stream from some unrelated process, etc.). Forced airflows 138 can be predictable, and can be tuned for efficiency (e.g., fast enough for high exposure without causing damage). However, the use of a fan 148 increases the energy cost of operation. Some embodiments may mitigate this cost (or at least front load part of it as a capital cost) through the use of a renewable source of electricity to power the forced airflow 138 (e.g., solar PV, wind, etc.). Ultimately, the choice of one type of airflow over another will depend on a number of factors including, but not limited to, the scale of the system 100, the capacities of the desiccant material 104 being used, and the cost of various forms of renewable sources of electricity.

[0079] The desorption configuration 124 is the configuration assumed by the extraction structure 102 when it is releasing or desorbing moisture it had previously adsorbed (sometimes referred to as regenerating the desiccant material 104). According to various embodiments, the desorption configuration 124 of an extraction structure 102 comprises the desiccant material 104 of that extraction structure 102 being in fluidic communication with the cooling surface 110 of the condensing chamber 106, and at least a second portion 130 of the desiccant material 104 being in thermal communication with the thermal liquid 118 such that the second portion 130 of the desiccant material 104 is heated to at least the release temperature140 (e.g., the temperature at which the desiccant material 104 will release the adsorbed water). While the extraction structure 102 is in the desorption configuration 124, the captured water is released as warm water vapor 112 which, upon contact with the cooling surface 110 of the condensing chamber 106, will condense into liquid water 114.

[0080] It should be noted that while the desorption configuration 124 only requires a part (i.e., the second portion 130) of the desiccant material 104 be in fluidic contact with the cooling surface 110 and in thermal communication with the thermal liquid 118, in some embodiments the desorption configuration 124 may include the entirety of the desiccant material 104 being in fluidic contact with the cooling surface 110 and also in thermal communication with the thermal liquid 118. See, for example, the embodiment shown in FIGs. 1 A-1C. As will be discussed in the context of the wheel-based embodiment of the AWE system 100, shown in FIG. 2, in some embodiments an extraction structure 102 may be able to be in two configurations at the same time. That discussion will be facilitated by this partitioning of the desiccant material 104.

[0081] In some embodiments, including the non-limiting example shown in FIGs. 1A-1C, each extraction structure 102 may have an enclosure 154, and the desorption configuration 124 for an extraction structure 102 may also include that extraction structure 102 being enclosed inside its enclosure 154 such that the desiccant material 104 is isolated from the atmosphere 126. Being enclosed within an enclosure 154 and isolated from the atmosphere 126 can significantly increase the effectiveness and efficiency of the other aspects of the desorption configuration 124, putting the desiccant material 104 in fluidic contact with the cooling surface 110 of the condensing chamber 106 and in thermal communication with the thermal liquid 118. Being enclosed means less loss of heat and the warm water vapor 112 being desorbed by the desiccant material 104. However, the use of an enclosure 154 and the intermittent isolation of the desiccant material 104 from the atmosphere 126 also means the inclusion of additional moving parts, which usually means an increase in both capital costs, as well as operational costs (e.g., more moving parts means more need for maintenance and / or replacement parts).

[0082] In some embodiments where the desorption configuration 124 of an extraction structure 102 includes isolation within an enclosure 154, transitioning into or out of the desorption configuration 124 may include moving the extraction structure 102, or at least part of the extraction structure 102. See, for example, the embodiment of the AWE system 100 shown in FIGs. 1 A-1C. Transitioning into the desorption configuration 124 includes lowering the extraction structure 102 into the enclosure 154, while transitioning out of the desorptionconfiguration 124 include extending the extraction structure 102 upward to once again expose the desiccant material 104 to the atmosphere 126.

[0083] In other embodiments, the extraction structure 102 (or at least the desiccant material 104 of the extraction structure 102) may remain stationary, and the intermittent isolation within an enclosure 154 may be accomplished through changes or movement of elements other than the desiccant material 104. Examples of such changes or movement that may occur when transitioning into or out of the desorption configuration 124 include, but are not limited to, the operation of vents, valves, windows, fans, and the like.

[0084] According to various embodiments, the adsorption configuration 122 includes the exposure of at least a portion (i.e., the first portion 128) of the desiccant material 104 to the atmosphere 126. That first portion 128 is in at least a partially unsaturated state 142, meaning that it still has at least some capacity to adsorb additional atmospheric water 134. When that first portion 128 reaches saturation, it is no longer adsorbing any additional atmospheric water 134, and there is nothing to be gained by remaining exposed to the atmosphere 126.

[0085] Similarly, the desorption configuration 124 includes the heating of at least a portion (i.e., the second portion 130) of the desiccant material 104 to at least the release temperature 140, causing the captured water to be released as warm water vapor 112. That second portion 130 is in at least a partially saturated state 144, meaning that it still has at least some water left to desorb. When that second portion 130 reaches desaturation, it is no longer releasing any additional water vapor 112; there is no additional water to be gained by maintaining the second portion 130 at the release temperature 140.

[0086] In some embodiments of the AWE system 100, an extraction structure 102 may be in the adsorption configuration 122 and the desorption configuration 124 at the same time. A non-limiting example of this will be discussed in the context of FIG. 2, below. However, there are embodiments of the contemplated AWE system 100 where an extraction structure 102 is entirely in the adsorption configuration 122 or entirely in the desorption configuration 124, but cannot simultaneously be in both. In these embodiments, the first portion 128 is also the second portion 130. The AWE system 100 shown in FIGs. 1A-1C is a non-limiting example of such an embodiment, though speaking of the extraction structures 102 individually. In some embodiments having more than one extraction structure 102, it is possible for the system 100 to have extraction structures 102 in both configurations, even if each extraction structure 102 is limited to one configuration at a time.

[0087] In the embodiments where an extraction structure 102 is incapable of being in both configurations at the same time, the decision regarding when to transition between the adsorption configuration 122 and the desorption configuration 124 can have a significant impact on the efficiency of the AWE system 100. As discussed above, the clear endpoints are the desiccant material 104 being in states of saturation and desaturation. However, there may be points of diminishing returns, and asymmetry between the adsorption and desorption processes within various embodiments. As a result, the ideal endpoints for the adsorption configuration 122 or desorption configuration 124 (or, put differently, the sign that the extraction structure 102 should be moved into the alternate configuration of those two) may vary from embodiment to embodiment, depending on a number of characteristics of a particular embodiment of the system 100 including, but not limited to, the uptake rate for the desiccant material 104, the relative speed of the desorption process, the energy cost of transitioning between the adsorption configuration 122 and the desorption configuration 124, how much liquid water 114 is produced in each cycle, and the like.

[0088] Additionally, because these AWE systems 100 are being used in conjunction with the atmosphere 126 and may be deployed in a wide range of environments, the timing of the cycle of configuration transitions may further be influenced by a dynamic local environment that may be difficult to fully anticipate, and may be best dealt with through on-site decisions regarding timing. In some embodiments, these decisions may be performed automatically by a control system communicatively coupled to the AWE system 100 and aware of local environmental factors (e.g., sensor data, data received from an external source, user input, etc.) such as the time of day, sunlight exposure, relative humidity, wind speed and direction, ambient temperature, the current saturation level of the desiccant material 104, and the like.

[0089] Of course, in some embodiments, the transition between the configurations may simply be triggered after a predetermined amount of time has elapsed. This may not lead to a maximum yield of liquid water 114, but has the advantage of simplicity and does not introduce additional points of failure like the incorporation of a complicated automated control system relying on sensors and / or communication with an external system.

[0090] As previously discussed, in some embodiments moving the extraction structure 102 from one configuration to another may involve moving the extraction structure 102, or parts of the extraction structure 102. In other embodiments, moving between configurations may instead involve movement or utilization of other aspects of the AWEsystem 100 (e.g., vents, valves, doors, fans, etc.) while the extraction structure 102, or at least the desiccant material 104, remains stationary.

[0091] As a specific example, in some embodiments, the AWE system 100 may further comprise an enclosure 154 for each extraction structure 102. In some of these embodiments, movement between the adsorption configuration 122 and the desorption configuration 124 may include the extraction structure 102 moving into (i.e. isolated from the atmosphere 126 in preparation for desorption) and out of (i.e., with the desiccant material 104 exposed to the atmospheric water 134 in an airflow 132) the enclosure 154. In other embodiments, the extraction structure 102 may remain stationary within an enclosure 154, and movement between the adsorption configuration 122 and the desorption configuration 124 may involve opening or closing vents, valves, windows, and other apertures, resulting in the desiccant material 104 being exposed to, or isolated from, the atmosphere 126 and its airflows. According to various embodiments, the movement between configurations may be accomplished using one or more actuators, or other means of driven motion known in the art.

[0092] Each AWE system 100 has at least one extraction structure 102. Some embodiments may comprise a single extraction structure 102. See, for example, the rotational AWE system 100 depicted schematically in FIG. 2. Other embodiments of the contemplated AWE system 100 may comprise multiple extraction structures 102. For example, in some embodiments, including the non-limiting example shown in FIGs. 1 A-1C, an AWE system 100 may comprise two extraction structures 102. In other embodiments, the AWE system 100 may comprise three, or more extraction structure 102. While the use of multiple extraction structures 102 will increase the footprint size of the system, it also facilitates a more efficient use of shared resources, such as the condensing chamber 106 and the heating subsystem 116.

[0093] In embodiments having a single extraction structure 102 and which are not able to be in both the adsorption configuration 122 and desorption configuration 124 at the same time, the utilization of the condensing chamber 106 and the heating subsystem 116 will be intermittent. Adding more extraction structures 102 to the system 100 gives those resources additional opportunities for utilization, rather than waiting for their turn to come again in the next cycle. In most cases, the cooling surface 110 and the heating subsystem 116 are not able to instantly start and stop their operation and energy usage. The cooling surface 110 needs to be maintained at a lowered temperature in anticipation of its next use. The thermal liquid 118 may continue to be circulated in a closed circuit 146 in between instances where it is used to raise a part of the desiccant material 104 to the release temperature 140. Allowing theseresources to be shared among multiple extraction structures 102 increases their utilization and decreases the amount of energy that is wasted while waiting.

[0094] Additionally, using additional extraction structures 102 with the same condensing chamber 106 may permit the production of a continuous, or near continuous, stream of high quality liquid water 114. While some extraction structures 102 are adsorbing atmospheric water 134, other extraction structures 102 can be desorbing water vapor 112, with the condensing chamber 106 cooling a continuous or near continuous stream of warm water vapor 112. In contract, an AWE system 100 having a single extraction structure 102 that is limited to binary operation (i.e., cannot be in the adsorption configuration 122 and desorption configuration 124 at the same time) will produce liquid water 114 intermittently, as a batch operation.

[0095] The specific, non-limiting example shown in FIGs. 1A-1C operates by alternating the two extraction structures 102, seen side by side, so that when one is in the adsorption configuration 122, the other is in the desorption configuration 124. When in the adsorption configuration 122, the extraction structure 102 is extended upward in a vertical column, with a plurality of beds 152 spread apart, exposing their desiccant material 104 to an ambient airflow 132. At the top of each extraction structure 102 is an electric fan 148 orblower, which may be run in either configuration to assist with distributing air over the desiccant beds 152. It should be noted that while the non-limiting example shown in FIGs. lA-lC may operate the two extraction structures 102 in alternating configurations, in other embodiments these two extraction structures 102 could be operated independently of each other, such that they could be in the same configuration or opposite configurations at any given time.

[0096] Once the desiccant material 104 is saturated (with moist air), the extraction structure 102 transitions into the desorption configuration 124 and the moisture-saturated beds 152 are lowered into the enclosure 154 and sealed for desorption. In this particular embodiment, the thermal liquid 118, having been heated by a solar-thermal heat source 120, is circulated by a heat exchanger 156 within the enclosure 154 while the fan 148 at the top drives off the saturated air from desiccator beds 152 as water vapor 112 and into the air / water-cooled condensing chamber 106. According to various embodiments, this hybridization can reduce the overall electrical energy for heating the AWE system 100 by using solar thermal energy; electrical energy cost could be further reduced by using on-site renewable energy.

[0097] FIG. 2 is a schematic view of a non-limiting example of another embodiment of the AWE system 100, having a rotating desiccant wheel. As can be seen, this wheel -based embodiment of the AWE system 100 is similar in design to traditional waterextraction devices. Both make use of rotating extraction structure 102 having desiccant material 104 (hereinafter referred to as a rotary desiccant 200) that is desorbed by blowing hot air over / through the desiccant material 104. However, unlike traditional systems, the AWE system 100 makes use of a thermal liquid-based heating subsystem 116, whose increased efficiency permits the use of lower temperature desiccant materials 104 and low-grade heat sources 120 while still outperforming tradition systems in terms of how much liquid water 114 can be produced per unit of energy input, according to various embodiments.

[0098] As shown, the rotary desiccant 200 is configured to rotate on an axle 202. According to various embodiments, the rotation of the rotary desiccant 200 is driven by an actuator 204 operatively coupled to the rotary desiccant 200. In some embodiments, the actuator 204 may be powered using on-site renewable energy, such as solar PV.

[0099] In some embodiments, the AWE system 100 may be passive, harvesting atmospheric water 134 from natural airflows 132 such as wind. Other embodiments, including the non-limiting example shown in FIG. 2, may use a forced airflow 138 to expose the desiccant material 104 to atmospheric water 134. According to various embodiments, a fan 148 pulls the humid ambient air into the system 100, through an air / water-cooled condensing chamber 106, and brings it into contact with the rotary desiccant 200. The air / water-cooled condensing chamber 106 is circulating liquid water 114 from a collecting tank 108.

[0100] According to various embodiments, the rotary desiccant 200 rotates slowly. During operation, there is an adsorption zone 208 (i.e., the first portion 128) and a regeneration or desorption zone 206 (i.e., the second portion 130). According to various embodiments, the desorption zone 206 comprises a point on the desiccant material 104 most proximate to the liquid-air heat exchanger 210 and the adsorption zone 208 comprises a point on the desiccant material 104 most distal to the liquid-air heat exchanger 210.

[0101] The rotation of the rotary desiccant 200 causes every part of the wheel to spend time in each of these zones. Because of the continual rotation of the rotary desiccant 200, the first portion 128 of the desiccant material 104 (i.e., the adsorption zone 208) may always be in at least a partially unsaturated state 142 and the second portion 130 of the desiccant material 104 (i.e., the desorption zone 206) is always in at least a partially saturated state 144, according to various embodiments. The inefficiency associated with trying to get water from a dry desiccant material 104 or capture water with a saturated desiccant material 104 may be avoided by modifying the rotation speed of the wheel and / or the ratio of the zone sizes / durations.

[0102] The ratio of zone size (i.e., a fraction of wheel surface area) or zone duration (i.e., a fraction of wheel period spent in each zone) may depend on the characteristics of the desiccant material 104 used and the energy budget allowed for operating the system 100 (e.g., a rotary desiccant 200 may rotate slower to avoid overrunning a tight energy budget, etc.). In a specific, non-limiting example, the zone ratio may be 3 / 4 adsorption zone 208 and 1 / 4 desorption zone 206, for a rotary desiccant 200 that rotates at 10-30 cycles / hour using a release temperature 140 temperature of 80-150 °C.

[0103] As the desiccant material 104 is regenerated, the saturated air absorbed by the desiccant material 104 is released by heat. Instead of using an electrical heater or coil as a conventional dehumidifier system, the contemplated system 100 uses the heat of a thermal liquid 118 to desorb the captured water vapor 112 with an increase in temperature. The thermal liquid 118 is heated by the heating subsystem 116 using one or more heat source 120 (e.g., solar thermal, waste heat, etc.), as previously discussed.

[0104] In some embodiments, including the non-limiting example shown in FIG. 2, the heating subsystem 116 may transfer heat to the desiccant material 104 for desorption using hot air, similar to a traditional extraction device. Specifically, the heating subsystem 116 includes a liquid-air heat exchanger 210 and a fan 148. For each extraction structure 102, the desorption configuration 124 includes at least the second portion 130 of the desiccant material 104 (i.e., the desorption zone 206 of the rotary desiccant 200) being in thermal communication with the thermal liquid 118 via a forced airflow 138 blown by the fan 148 through the liquidair heat exchanger 210 while the liquid-air heat exchanger 210 is in thermal contact with the thermal liquid 118. In other embodiments, the thermal liquid 118 may be in thermal communication with the desorption zone 206 (i.e., the second portion 130) through another means. For example, in some embodiments, the extraction structure 102 may comprise one or more lumina 306 through which the thermal liquid 118 may pass. This will be discussed further in the context of FIGs. 3A-4D

[0105] The desorbed, hot saturated water vapor 112 is blown through the condensing chamber 106, where it is condensed by the air / water-cooled cooling surface 110 and collected in the collecting tank 108. As the extraction structure 102 rotates it is continuously in the adsorption configuration 122 and the desorption configuration 124, with the thermal liquid 118 continuously heating the second portion 130 to at least the release temperature 140, and with the first portion 128 continuously in fluidic contact with the airflow 132 comprising atmospheric water 134, according to various embodiments.

[0106] The replacement of the traditional electric heater with a thermal liquid 118 heated by a solar-thermal (e.g., manifold of evacuated tubes, solar collectors, parabolic concentrator, etc.) or similar renewable heat source 120 serves to improve the overall energy sustainability and efficiency in harvesting water from the air. As an option, in some embodiments the electricity used to drive the fan 148 may be provided by renewable energy (e.g., PV, wind, geothermal, etc.) to further reduce the need for expensive external energy.

[0107] The similarity between the rotary desiccant-based AWE system 100 contemplated herein and a traditional wheel-based dehumidifier allows for the possibility of retrofitting a traditional extraction system. According to various embodiments, retrofitting a traditional rotary desiccant heating system may require replacing an existing electrical heater with a thermal liquid-based heating subsystem 116. The existing electrical heating block and all its electrical wiring, coil system, and components can be carefully removed and replaced with a liquid-air heat exchanger 210 in fluidic communication with the heating subsystem 116, as shown in FIG. 2. According to various embodiments, including embodiments that are not based on the rotary desiccant 200, the inlet and outlet temperatures, pressure, and flowrates within the thermal liquid-based heating subsystem 116 may all be carefully monitored by one or more sensors 212, according to various embodiments.

[0108] FIGs. 3A and 3B show perspective views of two non-limiting examples of the extraction structure 102 of an AWE system 100 making use of a thermal contact between the extraction structure 102 and the thermal liquid 118. Specifically, FIG. 3A shows an extraction structure 102 that comprises a desiccant material 104 held in a bed 152. FIG. 3B shows an extraction structure 102 comprising a desiccant material 104 deposed as a coating 304 on a substrate 300 having a lumen 306. Each will be discussed in turn.

[0109] The interface between the heating subsystem 116 and the desiccant material 104 may take many forms, according to various embodiments. In some embodiments, there is indirect thermal communication between the thermal liquid 118 and the desiccant material 104. For example, the heat exchanger 156 lining the enclosure 154 of FIG 1 A and the liquid-air heat exchanger 210 used with the rotary desiccant 200 of FIG. 2. In other embodiments, the connection may be more direct, resulting in less loss and greater efficiency. FIG. 3 A shows a non-limiting example of part of an extraction structure 102 comprising a bed 152 with an embedded conduit 308 having a thermal liquid input 312 and a thermal liquid output 314. The conduit 308 is surrounded by solid phase desiccant material 302. When thermal liquid 118 is run through the conduit 308 (i.e., when the extraction structure 102 is in the desorption configuration 124), the heat transfer from the thermal liquid 118 to the desiccant material 104is through the conduit 308, rather than via blown air as is shown in FIGs. 1 and 2. The conduit 308 is closed to the atmosphere 126, and is part of a closed circuit 146 of the heating subsystem 116 when it is in fluidic communication.

[0110] According to various embodiments, the conduit 308 may be constructed of materials well suited for thermal conduction including, but not limited to, metal, ceramic, plastic, and other materials. It should be noted that what is being referred to as a conduit 308 could also be described as a heat exchanger capable of transporting a liquid.[OHl] In some embodiments, the conduit 308 may be given a shape to increase the surface area of interaction between the solid phase desiccant material 302 and the conduit 308, to enhance heat transfer. As an option, the conduit 308 may be given surface features such as fins or other features common to heat sinks, to further increase the area of interaction between the desiccant material 104 and the conduit 308.

[0112] FIG. 3B takes this concept of direct interaction through a heat exchanging structure further. In some embodiments, the desiccant material 104 is coupled to a substrate 300. In the context of the present description and the claims that follow, a substrate 300 is a foundational material on which a layer of desiccant material 104 (e.g., solid phase desiccant material 302) may be coupled (i.e., deposed, coated, applied, etc.). The use of a substrate 300 gives additional freedom in designing the interface between the desiccant material 104 and a heat exchanging surface. For example, according to various embodiments, the substrate may have a geometry that is one of a pipe, a coil, a lumen, a plate, fibers, or other geometries where thermal liquid 118 is on the inside and desiccant materials 104 are on the outside (or vice versa).

[0113] In some embodiments, the substrate 300 may be used on conjunction with a conduit 308 transporting the thermal liquid 118. In other embodiments, the substrate 300 may comprise a lumen 306 or lumina 306 through which the thermal liquid 118 may pass. FIG. 3B is a non-limiting example of a substrate 300 having a lumen 306, with the substrate 300 covered with a coating 304 comprising a desiccant material 104 (e.g., solid phase desiccant material 302, etc.). Regeneration is accomplished when the lumen 306 is placed in fluidic contact with the heating subsystem 116 and thermal liquid 118 is passed through the lumen 306 (e.g., in via the thermal liquid input 312 and out via the thermal liquid output 314), as part of the desorption configuration 124. Like the bed 152, a substrate 300 may be composed of a material with high thermal conductivity or having desirable mechanical properties. Examples include, but are not limited to, metal, glass, ceramic, and thermally conductive polymer.

[0114] FIG. 4A shows a non-limiting example of a hollow fiber extraction structure 102 before being mounted in a frame or being coated with a desiccant material 104. FIGs. 4B-4D show perspective views of various non-limiting examples of hollow fiber-based heat exchangers (extraction structures 102) of an AWE system 100. In recent years, the use of polymeric (polypropylene) hollow fiber (HF) heat exchangers has gained some interest over conventional metal heat exchangers. These polymeric hollow fiber heat exchangers are much lighter than traditional metal-based (aluminum, copper, etc.) heat exchangers. They are also highly flexible and can be placed in different configurations, shapes, and sizes with low material costs. They have excellent resistance to both corrosion and mineral scaling. They can also handle high pressure. Although polymeric material is not typically considered a good heat exchanger or conductor, a polymeric hollow fiber with a thin wall (i.e., wall thickness < 0.1 mm) becomes a good heat exchanger with a larger heat transfer area that allows for effective heat transfer in water-water and water-air applications.

[0115] FIG. 4A shows a non-limiting example of a bundle of these polymeric hollow fibers 400, which act as heat exchangers, all sharing the same thermal liquid input 312 and thermal liquid output 314. These highly flexible polymeric hollow fibers 400 can be integrated, enmeshed, or coated with desiccant material 104, according to various embodiments. Put differently, these hollow fibers 400 may be used as a substrate 300 to which a desiccant material 104 may be coupled. Such integration allows localized heating in the near vicinity of desiccant materials 104 for releasing the adsorbed water. As a specific example, in some embodiments, hollow fiber heat exchangers may be enmeshed with silica gel 402 as the desiccant material 104. Silica gel 402 requires a lower temperature for regeneration (i.e., less than 100 °C as opposed to more than 180 °C for zeolite).

[0116] The benefit of this approach is a more efficient way of exchanging the heat. Instead of radiating the heat to heat-up bulk, ambient air to then heat the desiccant material 104 to the release temperature 140, heating would occur in the near vicinity of the desiccant material 104 by circulating heated thermal liquid 118 through these polymeric hollow fiber exchangers. This technique of embedding the polymeric hollow fiber heat exchanger within the desiccant material 104 can be used to make a variety of extraction structures 102, such as a desiccator wheel (FIG. 4B), a flat modular plate (FIG. 4C), or a column of the polymeric heat exchanger coated with desiccant material 104 as shown in FIG. 4D, which is similar to a metal heat exchanger but using polymeric hollow fibers 400.

[0117] These designs are also easier to implement as multi-segment extraction structures 102, like extraction structures 102 shown in FIGs. 1A-1C. Multiple plates can be added in a small footprint, as each plate is individually heated. Such a system will be moreefficient in energy use, with faster adsorption and desorption kinetics and higher operation cycles in extracting and producing water due to its unique design.

[0118] FIG. 5 is a process flow for a non-limiting example of a method for extracting atmospheric water 134. The method begins with exposing an extraction structure 102 comprising a desiccant material 104 to an atmosphere 126. See step 500. According to various embodiments, the extraction structure 102 is exposed such that the desiccant material 104 is in fluidic contact with an airflow 132 comprising atmospheric water 134. In some embodiments, the desiccant material 104 may be held by the extraction structure 102 in one or more beds 152. In other embodiments, the extraction structure 102 may comprise one or more substrates 300 to which desiccant material 104 is coupled. As an option, each substrate may have a lumen 306.

[0119] Next, the thermal liquid 118 of a heating subsystem 116 is placed in thermal contact with a heat source 120. See step 502. According to various embodiments, the heating subsystem 116 is thermal liquid 118-based and coupled to the extraction structure 102. The nature of the connection between the extraction structure 102 and the heating subsystem 116 is such that eventual thermal communication between the thermal liquid 118 and the desiccant material 104 is facilitated. For example, in an embodiment where the desiccant material 104 is coupled to a substrate 300 having a lumen 306, the heating subsystem 116 may be in fluidic contact with the lumen 306.

[0120] The desiccant material 104 of the extraction structure 102 is then placed in thermal communication with the thermal liquid 118 such that the desiccant material 104 is heated to at least a release temperature 140, causing the desiccant material 104 to release adsorbed 152 atmospheric water 134 as a water vapor 112. See step 504. The nature of the thermal communication between the thermal liquid 118 and the desiccant material 104 may vary from one embodiment to the next. For example, in an embodiment where the desiccant material 104 is coupled to a substrate 300 having a lumen 306, the heating subsystem 116 may pass the thermal liquid 118 through the lumen 306 to heat the desiccant material 104 to the release temperature 140.

[0121] According to various embodiments, the extraction structure 102 may be enclosed inside an enclosure 154 when the desiccant material 104 is placed in thermal communication with the thermal liquid 118, isolating the extraction structure 102 from the atmosphere 126. In some embodiments, this may be done while the desiccant material 104 remains stationary. In other embodiments, enclosing the extraction structure 102 inside the enclosure 154 may include the extraction structure 102 being moved into the enclosure 154.

[0122] Finally, the water vapor 112 is condensed into liquid water 114 on a cooling surface 110 of a condensing chamber 106 coupled to and in fluidic communication with the extraction structure 102. See step 506. In some embodiments, the cooling surface 110 may be cooled by an airflow 132, while in other embodiments the cooling surface 110 may be cooled using liquid water 114. As an option, in one embodiment that liquid water 114 may have been previously desorbed from the desiccant material 104 and stored in a collecting tank 108.

[0123] It will be understood that implementations are not limited to the specific components disclosed herein, as virtually any components consistent with the intended operation of a system, method, and / or device implementation for atmospheric water extraction may be utilized. Accordingly, for example, although particular systems, methods, materials, and / or devices for desiccation, thermal liquid-based heating, and condensing may be disclosed, such components may comprise any shape, size, style, type, model, version, class, grade, measurement, concentration, material, weight, quantity, and / or the like consistent with the intended operation of a system, method, and / or device implementation for atmospheric water extraction may be used. In places where the description above refers to particular implementations of a system, method, and / or device implementation for atmospheric water extraction, it should be readily apparent that a number of modifications may be made without departing from the spirit thereof and that these implementations may be applied to other gaseous water extraction systems and methods.REFERENCES1. Mulchandani, A., Westerhoff, P. “Geospatial climatic factors influence water production of solar desiccant driven atmospheric water capture devices”, Environmental Science and Technology https: / / d0i.0rg / l 0.1021 Zacs.est.0c00534 , 54: 13:8310- 8322 (2020).2. Mulchandani, A., Edberg, J., Herckes, P., Westerhoff, P. “Seasonal atmospheric water harvesting yield and water quality using electric-powered desiccant and compressor dehumidifiers”, Science of the Total Environment, 825: 153966, 11 pages https: / / doi.Org / 10.1016 / i.scitotenv.2022.153966 (2022) 3. Mulchandani, A., Malinda, S., Edberg, J., Westerhoff, P. “Sunlight-driven atmospheric water capture capacity is enhanced by nano-enabled photothermal desiccants” Environmental Science: Nano DOI: 10, 1039 / d0en00463d, 7:2584-2594 (2020) - Designated as a ESNano HOT article.4. Bartuli, E., Kudelova, T., Raudensky, C. M., “Shell-and-tube polymeric hollow fiber heat exchangers with parallel and crossed fibers”, Applied Thermal Engineering, https: / / doi.Org / 10.1016 / j.applthermaleng.2020.116001; (2020)

Claims

CLAIMSWhat is claimed is:

1. A system for atmospheric water extraction, comprising: at least one extraction structure, each extraction structure comprising a desiccant material, each extraction structure movable to an adsorption configuration, and also movable to a desorption configuration; a condensing chamber coupled to and in fluidic communication with the at least one extraction structure, the condensing chamber comprising a cooling surface and configured to receive a water vapor from the at least one extraction structure and condense the water vapor into liquid water on the cooling surface; and a heating subsystem that is thermal liquid-based, the heating subsystem coupled to the at least one extraction structure and comprising a thermal liquid in thermal contact with a heat source; wherein, for each extraction structure of the at least one extraction structure, the adsorption configuration comprises the extraction structure being exposed to an atmosphere such that at least a first portion of the desiccant material of the extraction structure is in fluidic contact with an airflow comprising atmospheric water; wherein, for each extraction structure of the at least one extraction structure, the desorption configuration comprises: the desiccant material of the extraction structure being in fluidic communication with the cooling surface of the condensing chamber; at least a second portion of the desiccant material in thermal communication with the thermal liquid such that at least the second portion of the desiccant material is heated to at least a release temperature, causing at least the second portion of the desiccant material to release adsorbed atmospheric water as water vapor; wherein the first portion of the desiccant material comprises desiccant material in at least a partially unsaturated state; wherein the second portion of the desiccant material comprises desiccant material in at least a partially saturated state.

2. The system of claim 1, further comprising: an enclosure for each extraction structure of the at least one extraction structure;wherein, for each extraction structure of the at least one extraction structure, the desorption configuration further comprises the extraction structure being enclosed inside the enclosure, isolated from the atmosphere.

3. The system of claim 1, wherein the desiccant material of the at least one extraction structure remains stationary when the extraction structure moves from the adsorption configuration to the desorption configuration.

4. The system of claim 1, further comprising: an enclosure for each extraction structure of the at least one extraction structure; wherein, for each extraction structure of the at least one extraction structure, moving between the adsorption configuration and the desorption configuration comprises the extraction structure moving into and out of the enclosure.

5. The system of claim 1, wherein the thermal liquid is circulating in a closed circuit.

6. The system of claim 1, wherein the heat source is solar thermal.

7. The system of claim 1, wherein the heat source is waste heat.

8. The system of claim 1, wherein the heat source is electric.

9. The system of claim 1, wherein the heat source is geothermal.

10. The system of claim 1 : wherein the at least one extraction structure is two extraction structures; and wherein when one extraction structure is in the adsorption configuration, the other extraction structure is in the desorption configuration.

11. The system of claim 1, wherein the at least one extraction structure comprises at least one bed comprising the desiccant material.

12. The system of claim 11, wherein the at least one extraction structure comprises a plurality of beds, each comprising the desiccant material and coupled to at least one other bed.

13. The system of claim 12: wherein, for each extraction structure of the at least one extraction structure, the adsorption configuration comprises the extraction structure extended vertically with the beds spread apart and exposed to the atmosphere, and the desorption configuration comprises the extraction structure retracted with the beds lowered into an enclosure such that the desiccant material is isolated from the atmosphere.

14. The system of claim 1, wherein the first portion is also the second portion.

15. The system of claim 1, wherein the cooling surface cooled by the airflow.

16. The system of claim 1, further comprising a collecting tank, wherein the condensing chamber is configured to store the liquid water in the collecting tank.

17. The system of claim 16, wherein the cooling surface is cooled by liquid water taken from the collecting tank.

18. The system of claim 1 : wherein the heating subsystem comprises a liquid-air heat exchanger and a fan; and wherein, for each extraction structure of the at least one extraction structure, the desorption configuration comprises at least the second portion of the desiccant material being in thermal communication with the thermal liquid via a forced airflow blown by the fan through the liquid-air heat exchanger.

19. The system of claim 1, wherein the at least one extraction structure comprises a substrate to which the desiccant material is coupled, the desiccant material being a solid phase desiccant material.

20. The system of claim 19:wherein the substrate comprises at least one lumen, with the at least one lumen in fluidic contact with the heating subsystem; and wherein, for each extraction structure of the at least one extraction structure, the desorption configuration further comprises at least the second portion of the desiccant material in thermal communication with the thermal liquid through the substrate, with the thermal liquid passing through the at least one lumen of the substrate.

21. The system of claim 20, wherein the desiccant material is a coating on the substrate.

22. The system of claim 20, wherein the substrate comprises a plurality of hollow fibers.

23. The system of claim 1 : wherein the at least one extraction structure is a rotary desiccant that is rotatably coupled to an axle and operatively coupled to an actuator; wherein the desiccant material is divided into the first portion and the second portion, with the first portion and the second portion changing location on the extraction structure as it rotates such that the first portion is always in at least a partially unsaturated state and the second portion is always in at least a partially saturated state; and wherein as the extraction structure rotates it is continuously in the adsorption configuration and the desorption configuration, with the thermal liquid continuously heating the second portion to at least the release temperature, and with the first portion continuously in fluidic contact with the airflow comprising atmospheric water.

24. The system of claim 1, wherein the airflow is a passive airflow.

25. The system of claim 1, wherein the release temperature is less than 100 °C.

26. The system of claim 1, wherein the desiccant material comprises silica gel.

27. A system for atmospheric water extraction, comprising: at least one extraction structure, each extraction structure comprising a desiccant material, each extraction structure movable between an adsorption configuration and a desorption configuration;a condensing chamber coupled to and in fluidic communication with the at least one extraction structure, the condensing chamber comprising a cooling surface and configured to receive a water vapor from the at least one extraction structure and condense the water vapor into liquid water on the cooling surface; and a heating subsystem that is thermal liquid-based, the heating subsystem coupled to the extraction structure and comprising a thermal liquid in thermal contact with a heat source; wherein, for each extraction structure of the at least one extraction structure, the adsorption configuration comprises the extraction structure being exposed to an atmosphere such that the desiccant material of the extraction structure is in fluidic contact with an airflow comprising atmospheric water; wherein, for each extraction structure of the at least one extraction structure, the desorption configuration comprises: the desiccant material of the extraction structure being in fluidic communication with the cooling surface of the condensing chamber; the desiccant material in thermal communication with the thermal liquid such that the desiccant material is heated to at least a release temperature, causing the desiccant material to release adsorbed atmospheric water as water vapor.

28. The system of claim 27, further comprising: an enclosure for each extraction structure of the at least one extraction structure; wherein, for each extraction structure of the at least one extraction structure, the desorption configuration further comprises the extraction structure being enclosed inside the enclosure, isolated from the atmosphere.

29. The system of claim 27, wherein the desiccant material of the at least one extraction structure remains stationary when the extraction structure moves between the adsorption configuration and the desorption configuration.

30. The system of claim 27, further comprising: an enclosure for each extraction structure of the at least one extraction structure; wherein, for each extraction structure of the at least one extraction structure, moving between the adsorption configuration and the desorption configuration comprises the extraction structure moving into and out of an enclosure.

31. The system of claim 27, wherein the thermal liquid is circulating in a closed circuit.

32. The system of claim 27, wherein the heat source is solar thermal.

33. The system of claim 27, wherein the heat source is waste heat.

34. The system of claim 27, wherein the heat source is electric.

35. The system of claim 27, wherein the heat source is geothermal.

36. The system of claim 27: wherein the at least one extraction structure is two extraction structures; and wherein when one extraction structure is in the adsorption configuration, the other extraction structure is in the desorption configuration.

37. The system of claim 27, wherein the at least one extraction structure comprises at least one bed comprising the desiccant material.

38. The system of claim 37, wherein the at least one extraction structure comprises a plurality of beds, each comprising the desiccant material and coupled to at least one other bed.

39. The system of claim 38: wherein, for each extraction structure of the at least one extraction structure, the adsorption configuration comprises the extraction structure extended vertically with the beds spread apart and exposed to the atmosphere, and the desorption configuration comprises the extraction structure retracted with the beds lowered into an enclosure such that the desiccant material is isolated from the atmosphere.

40. The system of claim 27, wherein the cooling surface cooled by the airflow.

41. The system of claim 27, further comprising a collecting tank, wherein the condensing chamber is configured to store the liquid water in the collecting tank.

42. The system of claim 41, wherein the cooling surface is cooled by liquid water taken from the collecting tank.

43. The system of claim 27: wherein the heating subsystem comprises a liquid-air heat exchanger and a fan; and wherein, for each extraction structure of the at least one extraction structure, the desorption configuration comprises the desiccant material being in thermal communication with the thermal liquid via a forced airflow blown by the fan through the liquid-air heat exchanger.

44. The system of claim 27, wherein the at least one extraction structure comprises a substrate to which the desiccant material is coupled, the desiccant material being a solid phase desiccant material.

45. The system of claim 44: wherein the substrate comprises at least one lumen, with the at least one lumen in fluidic contact with the heating subsystem; and wherein, for each extraction structure of the at least one extraction structure, the desorption configuration further comprises the desiccant material in thermal communication with the thermal liquid through the substrate, with the thermal liquid passing through the at least one lumen of the substrate.

46. The system of claim 45, wherein the desiccant material is a coating on the substrate.

47. The system of claim 45, wherein the substrate comprises a plurality of hollow fibers.

48. The system of claim 27, wherein the airflow is a passive airflow.

49. The system of claim 27, wherein the release temperature is less than 100 °C.

50. The system of claim 27, wherein the desiccant material comprises silica gel.

51. A method for extracting atmospheric water, comprising:exposing an extraction structure comprising a desiccant material to an atmosphere such that the desiccant material is in fluidic contact with an airflow comprising atmospheric water, the desiccant material being coupled to a substrate comprising at least one lumen; placing a thermal liquid of a heating subsystem in thermal contact with a heat source, wherein the heating subsystem is thermal liquid-based, coupled to the extraction structure, and in fluidic contact with the at least one lumen; placing the desiccant material of the extraction structure in thermal communication with the thermal liquid through the substrate, by passing the thermal liquid through the at least one lumen such that the desiccant material is heated to at least a release temperature, causing the desiccant material to release adsorbed atmospheric water as a water vapor; and condensing the water vapor into liquid water on a cooling surface of a condensing chamber coupled to and in fluidic communication with the extraction structure.

52. The method of claim 51, further comprising enclosing the extraction structure inside an enclosure, isolating the extraction structure from the atmosphere, before placing the desiccant material in thermal communication with the thermal liquid.

53. The method of claim 52, wherein enclosing the extraction structure inside the enclosure comprises closing the enclosure while the desiccant material remains stationary.

54. The method of claim 52, wherein enclosing the extraction structure inside the enclosure comprises the extraction structure moving into and out of the enclosure.

55. The method of claim 51, further comprising circulating the thermal liquid in a closed circuit.

56. The method of claim 51, wherein the heat source is solar thermal.

57. The method of claim 51, wherein the heat source is waste heat.

58. The method of claim 51, wherein the heat source is electric.

59. The method of claim 51, wherein the heat source is geothermal.

60. The method of claim 51, further comprising: exposing another extraction structure also comprising the desiccant material to the atmosphere such that the desiccant material is in fluidic contact with the airflow comprising atmospheric water, both extraction structures coupled to the condensing chamber and the heating subsystem.

61. The method of claim 60: wherein while one extraction structure is being exposed to the atmosphere, the desiccant material of the other extraction structure is in thermal communication with the thermal liquid.

62. The method of claim 51 : wherein the extraction structure comprises a plurality of beds, each bed comprising the desiccant material and coupled to at least one other bed; wherein exposing the extraction structure to the atmosphere comprises extending the extraction structure vertically with the plurality of beds spread apart, exposing the desiccant material to the atmosphere.

63. The method of claim 51, further comprising cooling the cooling surface with the airflow.

64. The method of claim 51, further comprising storing the liquid water in a collecting tank coupled to, and in fluidic communication with, the condensing chamber.

65. The method of claim 64, further comprising cooling the cooling surface with liquid water taken from the collecting tank.

66. The method of claim 51, wherein the desiccant material is a coating on the substrate.

67. The method of claim 51, wherein the substrate is a plurality of hollow fibers.

68. The method of claim 51, wherein the airflow is a passive airflow.

69. The method of claim 51, wherein the release temperature is less than 200 °C.

70. The method of claim 51, wherein the desiccant material comprises silica gel.

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