WO2024165891A1

WO2024165891A1 - Atmospheric water generation systems and methods

Info

Publication number: WO2024165891A1
Application number: PCT/IB2023/051126
Authority: WO
Inventors: Miguel RICO LUENGO; Szymon BIALON; Riccardo CLAVENNA; Chin Lee ONG
Original assignee: Freshape Sa
Priority date: 2023-02-08
Filing date: 2023-02-08
Publication date: 2024-08-15

Abstract

There is in particular described an atmospheric water generation system comprising first and second adsorber units (10, 10') each configured to operate alternately in an adsorption cycle and in a desorption cycle. The atmospheric water generation system further comprises a thermoelectric device (30) with a first side (30A) thermally coupled to the first adsorber unit (10) and a second side (30B) thermally coupled to the second adsorber unit (10'). The thermoelectric device (30) is operable such that one of the first and second sides (30A, 30B) of the thermoelectric device (30) is turned into a cold side (CS), while the other one of the first and second sides (30A, 30B) of the thermoelectric device (30) is turned into a hot side (HS). The atmospheric water generation system is configured such that, in operation, the cold side (CS) of the thermoelectric device (30) is thermally coupled to that one of the first and second adsorber units (10, 10') that undergoes the adsorption cycle, while the hot side (HS) of the thermoelectric device (30) is thermally coupled to that one of the first and second adsorber units (10, 10') that undergoes the desorption cycle.

Description

ATMOSPHERIC WATER GENERATION SYSTEMS AND METHODS

TECHNICAL FIELD

The present invention generally relates to atmospheric water generation systems and methods.

BACKGROUND OF THE INVENTION

Atmospheric water generation (also referred to by the acronym “AWG”) - or atmospheric water harvesting (“AWH”) - is known as such in the art and has gained significant interest as a potentially viable method for sustainable potable water production. Indeed, fresh water scarcity is increasingly affecting human population and more and more people are suffering from restrictions to potable water access, which problem is growing day by day. By 2025, it is estimated that approximately 1.8 billion people will be living in absolute water scarcity regions, while two thirds of the world’s population will be living under water stressed conditions. By 2030, half of the world’s population could be living under high water stress, i.e. without access to clean, fresh and safe drinking water.

Different solutions have been proposed in the art to address this problem, mainly (i) desalination and (ii) atmospheric water generation/harvesting (AWG/AWH). Desalination is a suitable solution allowing for high-capacity production. This solution is however only viable in coastal areas or in areas allowing in-land desalination with saline groundwater. AWG is a highly sustainable water production solution which in essence relies on capturing moisture from the air/atmosphere. Even in the driest of places, air humidity level is never zero, and a certain amount of water is always present in the air.

AWG technologies can in essence be segregated into three main categories, namely (i) solar stills, (ii) refrigeration systems/processes, and (iii) adsorption systems/processes, there being however further solutions.

Solar stills are relatively easy to setup as they only require a water container, a transparent collector and sunshine. This approach allows production of distilled water from undrinkable water sources from streams or lake water, saline water, or even brackish or contaminated water. The main disadvantage of this approach however resides in the fact that it requires an existing water source to be distilled for potable water production.

Refrigeration systems/processes requires a suitable system to deploy a refrigeration cycle, typically vapor compression using a compressor, condenser and evaporator for atmospheric water harvesting. Advantages include high mobility and up-scalable production capability. The main disadvantage however resides in the high energy consumption requirements, especially when relative humidity (RH) is low, in particular below 40%.

Adsorption systems/processes are typically based on thermal desiccation, a process using adsorbent materials (e.g. porous solids) to adsorb moisture from the atmosphere, desorb the adsorbed moisture, and then condense to produce a condensate. The main advantage of this approach resides in the fact that the desorption process only consumes low-grade heat as the relevant driving force and is deployable even for low humidity conditions. A small amount of electricity may be required for forced circulation of moist ambient air through the adsorbent material during the adsorption process. The main disadvantage resides in the fact that production is greatly dependent on the adsorbent characteristics of the adsorbent material being used.

The most widely deployed AWG solutions are typically based on (i) vapor compression (refrigeration and compressor based) or (ii) thermal desiccation with adsorbents. As pointed out previously, refrigeration-based AWG consumes electricity, while desiccant-based AWG essentially requires low-grade thermal energy as the driving force. For refrigeration-based AWG, water production costs may be lowered through integration with a solar energy source or any other renewable energy source (such as wind) to cover the required electricity consumption. For thermal, desiccant-based AWG, integration with a solar thermal energy source or industrial waste heat source substantially lowers water production costs, as the relevant thermal energy requirements are thereby fulfilled and only a small amount of electricity is required to circulate moist ambient air during the adsorption phase.

There is no best method for AWG and selection of the most suitable process is essentially dependent on the performance and economical feasibility of the AWG solution that is to be implemented. Key variables for such selection include:

- external atmospheric conditions (especially the relevant RH level), which dictate the amount of air moisture, which in turn affects water production rate and water recovery efficiency;

- the degree of complexity of the AWG system to be implemented, which impacts capital expenditure (CAPEX) and operational expenditure (OPEX);

- energy efficiency, i.e. the amount of energy required for efficient water recovery to increase overall system efficiency; and

- the ability to integrate renewable energy sources to fulfil the relevant energy consumption requirements and thereby achieve sustainable AWG.

AWG systems/processes based on vapor compression are the most commonly available solutions on the market today. Such AWG systems/processes are also referred to as cooling condensation AWGs and in essence operate in a manner similar to a dehumidifier. More specifically, a compressor is typically used to circulate a refrigerant through a condenser and then through an evaporator coil which cools the air surrounding it. Moist air is drawn across an electrostatic air filter and directed towards the evaporator coil. Moist air surrounding the evaporator coil is cooled down below its dew point, causing water to condense. The resulting condensate is then collected into a tank before being pumped out of the system, usually through a purification and filtration system. During the vapor condensation process, heat from the moist air is transferred into the refrigerant via flow boiling of the refrigerant flowing through the evaporator coil. Evaporated refrigerant in saturated vapor phase is then channelled back to the compressor before being compressed to higher saturation pressure/temperature. The compressed vapor phase refrigerant then undergoes condensation in the condenser. Latent heat resulting from such condensation is transferred from the refrigerant into dry dehumidified air which is rejected into the environment. The advantage of such a cooling condensation AWG resides in the fact that it is reasonably energy efficient when relative humidity (RH) of the ambient air exceeds 60%. The compressor however consumes a lot of energy, which means that, for lower ambient air RH levels, energy efficiency becomes an issue. Another drawback of this solution resides in the fact that it requires large volumes of air to be cooled below its dew point to harvest and condense the water vapor, rendering these systems highly energy intensive for certain low humidity ambient conditions.

AWG systems/processes based on thermal desiccation are used less widely but have great potential. Such technology essentially capitalizes on the use of adsorbent materials that are capable of inducing attraction and surface bonding of adsorbates, in this case water molecules. Water harvesting with such technology mainly involves three main phases, namely (i) an adsorption phase during which the adsorbent material is in essence cooled and fed with moist ambient air to induce bonding with the water molecules contained in the air, (ii) a desorption phase (also referred to as regeneration phase) during which the adsorbent material is heated to cause vaporization of the adsorbed water into water vapor, and (iii) a vapor condensation phase during which the water vapor is caused to condense into a condensate.

Known AWG solutions based on thermal desiccation are for instance disclosed in U.S. Patents Nos. US 4,146,372 A, US 6,336,957 B1 , US 6,863,711 B2, US 7,467,523 B2, US 9,234,667 B1 , US 10,683,644 B2, and US 10,835,861 B2.

Typical adsorbent materials include silica, silica gel, zeolites, alumina gel, molecular sieves, montmorillonite clay, activated carbon, hygroscopic salts, metal-organic frameworks (MOF) such as zirconium or cobalt based adsorbents, hydrophilic polymer or cellulose fibers, and derivatives of combinations thereof.

The advantage of thermal-desiccant-based AWG systems resides in the fact that they remain economically feasible even when deployed in regions with low RH levels. Furthermore, such solutions do not require any moving components such as compressors or pumps for refrigeration flow, which renders these solutions more robust and more cost-efficient to operate, and with higher performance durability.

International (PCT) Application No. PCT/IB2021/059253 of October 8, 2021 , titled “ATMOSPHERIC WATER GENERATION SYSTEM AND METHOD”, in the name of the present Applicant, discloses a variety of atmospheric water generation systems and methods that rely on the use at least one adsorber unit including at least two successive adsorber stages each including an adsorbent structure comprising an adsorbent material, which adsorbent structure is coupled to an adjacent vapor chamber to allow vapor transfer thereto. The adsorber unit further includes a heating stage to provide thermal energy to the adsorbent structures and a cooling stage to cause condensation of water vapor in at least a final one of the vapor chambers. The adsorber unit also comprises an air circuit to force circulation of moist ambient air through the adsorbent structures, during an adsorption cycle of the adsorber unit, and cause adsorption of water therein. During a desorption cycle of the adsorber unit, the heating stage is operated such that thermal energy provided by the heating stage causes water adsorbed in the adsorbent structures to be desorbed into water vapor, which water vapor transits to the adjacent vapor chamber where the water vapor condenses into a condensate. By way of preference, the adsorber unit is configured such that latent heat resulting from condensation of the water vapor generated by a preceding adsorber stage is transferred to the adsorbent structure of following adsorber stage to sustain desorption.

In accordance with International (PCT) Application No. PCT/IB2021/059253, the adsorber unit is typically coupled to a thermal storage device or to a thermal energy source capable of supplying thermal energy. The thermal energy source may especially originate from solar energy or industrial waste heat processes. Such a thermal energy source might not necessarily be readily available and an alternate solution therefore needs to be contemplated in such case.

Exploitation of electrically-powered devices has separately been contemplated in the art. International (PCT) Publication No. WO 2013/026126 A1 discloses an atmospheric water generator including a housing containing a substantially parallel array of plates mounted to and between a parallel pair of cooling walls having thermoelectric Peltier-effect modules mounted thereon which cool the cooling walls and hence cool the plates. The plates are spaced apart to form airways and are each formed, when viewed in lateral cross-section, as substantially sinusoidally corrugated plates. A parallel, spaced apart array of ridges is formed on and along the length of each corrugation on both the inner and outer surfaces of each corrugation. Each ridge extends along a corresponding airway in the direction of flow of the stream of air. A shaker is mounted to vibrate the array of plates. The plates are maintained just above freezing, for example at substantially three degrees centigrade above zero, irrespective of the local dew point in the airways. This solution capitalizes on the use of Peltier-effect modules to cool humid ambient air below dew point to produce condensate within the cold chamber.

U.S. Patent Publication No. US 2010/0058778 A1 discloses a system for cooling using indirect evaporative cooling, dehumidification using desiccant, and a thermoelectrically powered heat exchanger. The thermoelectric heat exchanger pulls heat from the working air exiting the indirect evaporating cooler and injects that energy into ambient air that is then forced through a portion of a rotating desiccant wheel to regenerate the desiccant by removing water molecules from the desiccant material. Liquid water that is condensed by cooling the working air with the thermoelectric heat exchanger is saved and provided to the indirect evaporating cooler for use to cool via evaporation.

U.S. Patent Publication No. US 2010/0043633 A1 discloses methods, devices and systems for carrying out sorption (adsorption and absorption) for separating and/or purifying fluid mixtures. In one embodiment, a thermoelectrically driven temperature swing gas dryer is contemplated to provide hot dry gas for adsorbent regeneration purposes. The dryer is operated periodically or during periods of system inactivity to maintain system adsorbent performance. More specifically, thermoelectric devices are cycled to create temperature variations in moisture adsorption chambers. The resulting dry air is heated by a resistance heater and used to regenerate the gas separation adsorbents. This system may be part of a gas separation module or may be contained in a docking station such as would be used to charge and regenerate a portable medical oxygen concentrator.

U.S. Patent Publication No. US 2006/0288709 A1 discloses a water generating device utilizing thermoelectric cooling for obtaining potable water from ambient air inside or outside a structure or dwelling, having a unique continuous duct for bringing the supply of ambient air to the device and for releasing the air back outside the device after it has been processed. The device includes a cold sink with which the incoming air is cooled below the dew point to condense the existing water vapor. The cooled air is then redirected over a heat sink which increases the efficiency and cooling capability of the device over that of using only the warmer ambient air to cool the heat sink. The rate of airflow is controlled by the variable speed of one or more fans or blowers. The fan or blower speed in turn is controlled by a device that determines the current ambient dew point by measuring the temperature and relative humidity, and the temperature of the cold sink. The incoming airflow is increased or decreased by the fan or blower to the maximum possible flow rate without excessively exceeding the determined dew point temperature of the incoming air being processed.

U.S. Patent No. US 9,587,381 B2 discloses a system for condensing water from air including a column having a substantially non-reflective surface effective for absorbing heat energy from the sun and transferring the heat to air in the interior of the column. A condenser is secured within the column and includes a channel having a condensing surface with e.g. a thermoelectric cooler positioned thereon for cooling the condensing surface. A collector is positioned within the column for collecting water that condenses on and flows through the channel, and an accumulator is coupled in fluid communication with the collector for accumulating the water.

U.S. Patent No. US 7,559,204 B2 discloses a water generating device for extracting water vapor from ambient air circulated therethrough. The device comprises an air pathway, a fan, a Peltier module, a collection reservoir, and a heat sink. The air pathway defines first and second sections. A cold side of the Peltier module is disposed in the first section and a hot side of the Peltier module, whereto the heat sink is attached, is disposed in the second section. The fan draws the ambient air into the air pathway, and the cold side of the Peltier module extracts water vapor out of the ambient air, which collects as water in the collection reservoir. The heat sink is partially disposable in the water and also includes a capillary tube which draws the water thereinto. Additional water vapor is extracted from the air, creating substantially dry air.

There however remains a need for an improved solution, especially one that exhibits better efficiency.

SUMMARY OF THE INVENTION

A general aim of the invention is to provide an atmospheric water generation system and related method that obviate the limitations and drawbacks of the prior art solutions.

More specifically, an aim of the present invention is to provide such a solution that is highly efficient and moreover cost-efficient to implement and operate.

A further aim of the invention is to provide such a solution that is modular and easily up-scalable to increase and adjust system throughput to the required needs.

Another aim of the invention is to provide such a solution that ensures efficient heat recovery and re-heat over multiple cycles for carrying out the desorption (regenerative) phase of the adsorbents.

Yet another aim of the invention is to provide such a solution that exhibits lower systemic energy consumption requirements (both electrical and thermal) and minimizes thermodynamic losses.

A further aim of the invention is to provide such a solution that can suitably make use of a variety of electrically-powered heating devices to drive desorption of at least one adsorber unit.

Still another aim of the invention is to provide such a solution that can especially be implemented in environments where thermal energy sources, such as solar energy or waste heat from e.g. industrial processes is not readily available or insufficient to efficiently drive a desorption process. At least part of these aims, and others, are achieved thanks to the solutions defined in the claims.

There is accordingly provided, in accordance with a first aspect of the invention, an atmospheric water generation system, the features of which are recited in claim 1 , namely, an atmospheric water generation system comprising first and second adsorber units each configured to operate alternately in an adsorption cycle and in a desorption cycle. The atmospheric water generation system further comprises a thermoelectric device with a first side thermally coupled to the first adsorber unit and a second side thermally coupled to the second adsorber unit. The thermoelectric device is operable such that one of the first and second sides of the thermoelectric device is turned into a cold side, while the other one of the first and second sides of the thermoelectric device is turned into a hot side. The atmospheric water generation system is configured such that, in operation, the cold side of the thermoelectric device is thermally coupled to that one of the first and second adsorber units that undergoes the adsorption cycle, while the hot side of the thermoelectric device is thermally coupled to that one of the first and second adsorber units that undergoes the desorption cycle.

Various preferred and/or advantageous embodiments of this atmospheric water generation system form the subject-matter of dependent claims 2 to 16 and 31.

There is further provided, according to this first aspect of the invention, an atmospheric water generation method, the features of which are recited in independent claim 32, namely an atmospheric water generation method comprising:

(a) providing first and second adsorber units each configured to operate alternately in an adsorption cycle and in a desorption cycle;

(b) providing a thermoelectric device having first and second sides;

(c) thermally coupling the first side of the thermoelectric device to the first adsorber unit and the second side of the thermoelectric device to the second adsorber unit;

(d) operating the thermoelectric device to turn one of the first and second sides of the thermoelectric device into a cold side, while the other one of the first and second sides of the thermoelectric device is turned into a hot side; and

(e) recovering condensate resulting from condensation of water vapor occurring in that one of the first and second adsorber units that undergoes the desorption cycle, wherein that one of the first and second adsorber units that is thermally coupled to the cold side of the thermoelectric device undergoes the adsorption cycle, while that one of the first and second adsorber units that is thermally coupled to the hot side of the thermoelectric device undergoes the desorption cycle.

Various preferred and/or advantageous embodiments of this atmospheric water generation method form the subject-matter of dependent claims 33 to 38, 48 and 49.

According to this first aspect of the invention, the thermoelectric device is advantageously coupled between the first and second adsorber units to cause such adsorber units to operate alternately in an adsorption cycle and in a desorption cycle, operation being switched and reversed at the end of each cycle to allow for continuous or semicontinuous production of condensate.

There is also provided, in accordance with a second aspect of the invention, an atmospheric water generation system, the features of which are recited in independent claim 17, namely, an atmospheric water generation system comprising an adsorber unit configured to operate alternately in an adsorption cycle and in a desorption cycle. The atmospheric water generation system further comprises an electrically-powered heating device that is thermally coupled to the adsorber unit. The adsorber unit includes a plurality of successive adsorber stages each including an adsorbent section coupled to an adjacent vapor chamber to allow vapor transfer thereto. The electrically-powered heating device is thermally coupled to the adsorbent section of a first one of the adsorber stages to selectively supply thermal energy thereto. The adsorbent section of each subsequent one of the adsorber stages is thermally coupled to the vapor chamber of the preceding adsorber stage to allow transfer of thermal energy between the adsorber stages. The adsorber unit further includes a cooling stage that is thermally coupled to the vapor chamber of a last one of the adsorber stage. Furthermore, the electrically-powered heating device is powered to operate the adsorber unit in the desorption cycle and supply thermal energy to the adsorbent section of the first adsorber stage to drive desorption of water adsorbed into the adsorbent sections of the adsorber unit.

Various preferred and/or advantageous embodiments of this atmospheric water generation system form the subject-matter of dependent claims 18 to 31 .

There is further provided, according to this second aspect of the invention, an atmospheric water generation method, the features of which are recited in independent claim 39, namely an atmospheric water generation method comprising:

(a) providing an adsorber unit configured to operate alternately in an adsorption cycle and in a desorption cycle, wherein the adsorber unit includes two or more successive adsorber stages each including an adsorbent section coupled to an adjacent vapor chamber to allow vapor transfer thereto;

(b) providing an electrically-powered heating device;

(c) thermally coupling the electrically-powered heating device to the adsorbent section of a first one of the adsorber stages, wherein the adsorbent section of each subsequent one of the adsorber stages is thermally coupled to the vapor chamber of the preceding adsorber stage to allow transfer of thermal energy between the adsorber stages;

(d) selectively operating the electrically-powered heating device to supply thermal energy to the adsorbent sections of the adsorber unit to undergo the desorption cycle and cause water adsorbed in the adsorbent sections to be desorbed into water vapor, which water vapor transits to the adjacent vapor chambers; and

(e) condensing the water vapor contained in the vapor chambers into a condensate when the adsorber unit is being operated to undergo the desorption cycle.

Various preferred and/or advantageous embodiments of this atmospheric water generation method form the subject-matter of dependent claims 40 to 49. According to this second aspect of the invention, the desorption cycle of the adsorber unit is accordingly driven and sustained by thermal energy supplied by the electrically-powered heating device, which thermal energy is transferred to the adsorbent section of the first adsorbent stage and, in sequence, to each following adsorbent stage of the adsorber unit.

Further advantageous embodiments of the invention are discussed below.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the present invention will appear more clearly from reading the following detailed description of embodiments of the invention which are presented solely by way of non-restrictive examples and illustrated by the attached drawings in which:

Figure 1A is a schematic, partially exploded diagram of a top view of an atmospheric water generation system (AWGS) comprising a thermoelectric device in accordance with one embodiment of the invention;

Figure 1 B is a schematic, partially exploded diagram of a side view of the AWGS of Figure 1A;

Figure 2 is schematic explanatory diagram illustrating operation of the AWGS of Figures 1A-B in accordance with a first operating mode;

Figure 3A is a schematic perspective view of an embodiment of a heat exchanger as used e.g. in the context of the AWGS of Figures 1 A-B and 2;

Figure 3B is a schematic, partially exploded perspective view of the heat exchanger of Figure 3A shown in combination with a thermoelectric device comprising a plurality of Peltier elements that are thermally coupled to one side of the heat exchanger;

Figure 3C is a schematic perspective view of an assembly consisting of two heat exchangers as shown in Figure 3A and a thermoelectric device as shown in Figure 3B that is sandwiched therebetween;

Figure 4 is a schematic, partially exploded view of an AWGS comprising the assembly of Figure 3C in accordance with a preferred embodiment of the invention; Figure 5 is a partial explanatory diagram illustrating operation of an AWGS whose desorption cycle is driven by an electrically-powered heating device in accordance with another embodiment of the invention;

Figures 6A and 6B are schematic, partially exploded perspective views of a silicon heater with integral adsorbent structure shown from two different viewing angles, which silicon heater is usable as electrically-powered heating device of the AWGS of Figure 5;

Figure 6C is an enlarged, partial perspective view of the adsorbent structure provided on the silicon heater of Figures 6A-B;

Figure 7A is a schematic, partially exploded perspective view of a cartridge heater with integral adsorbent structure, which cartridge heater is usable as electrically-powered heating device of the AWGS of Figure 5; and

Figures 7B and 7C are schematic perspective views of the cartridge heater of Figure 7A shown from two different perspectives.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The present invention will be described in relation to various illustrative embodiments. It shall be understood that the scope of the invention encompasses all combinations and sub-combinations of the features of the embodiments disclosed herein as defined by the appended claims.

As described herein, when two or more parts or components are described as being connected, attached, secured or coupled to one another, they can be so connected, attached, secured or coupled directly to each other or through one or more intermediary parts.

Figures 1 A and 1 B are schematic diagrams of an embodiment of an AWGS in accordance with a first aspect of the invention. This AWGS is based on the exploitation of a thermoelectric device 30 to drive adsorption and desorption in first and second adsorber units 10, 10’ that are thermally coupled to the thermoelectric device 30. The thermoelectric device 30 is also referred to as an electrically-operated heating device HT that drives desorption in one or the other adsorber unit 10 or 10’. Figure 1A schematically shows a partially exploded top view of the AWGS, while Figure 1 B schematically shows a partially exploded side view of the AWGS. More specifically, each of the first and second adsorber units 10, 10’ is configured to operate alternately in an adsorption cycle and in a desorption cycle. In the illustrations of Figures 1A-B, the first adsorber unit 10 on the right-hand side is shown as undergoing a desorption cycle, while the second adsorber unit 10’ on the left-hand side is shown as undergoing an adsorption cycle, it being understood that operation of the first and second adsorber units 10, 10’ can selectively be reversed as described below.

In the illustrated example, the adsorber units 10, 10’ share the same configuration and each preferably include a plurality of successive adsorber stages 21-24 (as schematically shown in Figure 1 B) - also referred to as “effects” - each including an adsorbent section AD coupled to an adjacent vapor chamber VC to allow vapor transfer thereto. Any number of adsorber stages could be contemplated, Figure 1 B showing four such adsorber stages 21 -24. From a practical perspective, the integer number n of adsorber stages that may be contemplated may advantageously range from 2 to 10. The actual number of adsorber stages used in practice will be selected depending on, especially, the type of adsorbent material being used, as well as the prevailing atmospheric conditions and ambient temperatures in which the system is to be deployed. More stages/effects may for instance be required if ambient temperatures are low. Also visible in Figure 1 B is a cooling stage CL that is thermally coupled to the vapor chamber VC of a last one (namely, adsorber stage 24 in the illustrated example) of the adsorber stages 21 , 22, 23, 24. The thermoelectric device 30 is thermally coupled to the adsorbent section AD of a first one (namely, adsorber stage 21 in the illustrated example) of the adsorber stages 21 , 22, 23, 24 and is designed to act as heating stage of the adsorber unit 10, resp. 10’, when operated in the desorption cycle.

The thermoelectric device 30 has a first side 30A that is thermally coupled to the first adsorber unit 10 and a second side 30B that is thermally coupled to the second adsorber unit 10’. In accordance with this preferred embodiment, the first and second sides 30A, 30B of the thermoelectric device 30 are each thermally coupled to, respectively, the first and second adsorber units 10, 10’ via a corresponding heat exchanger 35A, 35B. Advantageously, a layer of thermal interface material TIM may be provided between each of the first and second adsorber units 10, 10’ and the associated heat exchanger 35A, 35B to improve thermal transfer to adsorber units 10, 10’.

The thermoelectric device 30 is operable such that one of the first and second sides 30A, 30B (namely, the second side 30B in the illustrated example) is turned into a cold side CS, while the other one of the first and second sides 30A, 30B (namely, the first side 30A in the illustrated example) is turned into a hot side HS. In operation, the cold side CS of the thermoelectric device 30 is thermally coupled to that one of the first and second adsorber units 10, 10’ that undergoes the adsorption cycle (here the second adsorber unit 10’), while the hot side HS of the thermoelectric device 30 is thermally coupled to that one of the first and second adsorber units 10, 10’ that undergoes the desorption cycle (here the first adsorber unit 10).

The thermoelectric device 30 may conveniently be operable such that a polarity thereof can be reversed to switch the cold side CS and the hot side HS, and thus switch the first and second adsorber units 10, 10’ to undergo the other one of the adsorption and desorption cycles. In the illustrated example, by switching the polarity of the thermoelectric device 30, the second side 30B may accordingly be turned into the hot side HS to drive the second adsorber unit 10’ to operate in the desorption cycle, while the first side 30A is turned into the cold side CS to drive the first adsorber unit 10 to operate in the adsorption cycle. Operation of the first and second adsorber units 10, 10’ can thus be switched periodically and alternately between the adsorption and desorption cycles.

Each heat exchanger 35A, 35B preferably includes a radiator element 350 comprising radiator channels 360 that extend longitudinally through the radiator element 350 (here from the bottom side to the top side) to channel airflow from an input port 361 to an output port 362. By way of illustration, the input and output ports 361 , 362 are respectively located on the bottom and top sides of the radiator element 350, but other configurations could perfectly be contemplated and the actual direction of airflow through each radiator element 350 is not critical. As this will be explained in greater detail below, the radiator channels 360 are preferably provided to allow precooling of ambient air prior to feeding thereof to the adsorbent part AD of the relevant adsorber unit 10, 10’ that undergoes the adsorption cycle. During the desorption cycle, the radiator channels 360 are preferably closed to avoid airflow therethrough and maximize heat transfer across the radiator element 350.

Even more preferably, each radiator element 350 (see also Figures 2, 3A-C and 4) comprises first and second outer radiator sides 350A, 350B, the first outer radiator side 350A being thermally coupled to the first side 30A, respectively the second side 30B of the thermoelectric device 30, and the second outer radiator side 350B being thermally coupled to, respectively, the first adsorber unit 10, respectively the second adsorber unit 10’. In the illustrated example, each heat exchanger 35A, 35B further includes a thermally conductive bridge structure 380 thermally coupling the first outer radiator side 350A to the second outer radiator side 350B. This thermally conductive bridge structure 380 is designed to allow thermal energy to be transferred from the hot side HS of the thermoelectric device 30, across the radiator element 350, to the adsorbent part AD of that one of the first and second adsorber units 10, 10’ that undergoes the desorption cycle.

The thermally conductive bridge structure 380 could potentially be omitted, using the body of the radiator element 350 to transfer thermal energy to the adjacent adsorber unit 10, 10’, when operated in the desorption cycle. The presence of the radiator channels 360 may however impact heat transfer efficiency, and the provision of the thermally conductive bridge structure 380 is accordingly preferred to improve heat transfer efficiency across the radiator element 350.

In accordance with a particularly preferred embodiment, the thermally conductive bridge structure includes a plurality of heat pipes 380 extending from the first outer radiator side 350A to the second outer radiator side 350B around flanks of the radiator element 350, as schematically illustrated in Figures 1A-B and 2 (see also Figures 3A-C and 4). It will be understood that each heat pipe 380 basically consists, as is conventional in the art, of a sealed pipe or tube made of e.g. copper or aluminium, which is partially filled with a working fluid, such as water or ammonia, whose mass is chosen so that the heat pipe contains both vapor and liquid over the desired operating temperature range. Heat pipes 380 are preferred due to their particularly high heat transfer efficiency.

Referring to Figure 2, there is shown a schematic explanatory diagram illustrating operation of the AWGS of Figures 1A-B in accordance with an operating mode where, as previously mentioned, the first and second adsorber units 10, 10’ respectively undergo a desorption cycle and an adsorption cycle.

In the operating mode illustrated in Figure 2, humid/moist ambient air is drawn (from a suitable air intake) and first channelled through the radiator channels 360 of the radiator element 350 that is thermally coupled to the cold side CS of the thermoelectric element 30. As a result, ambient air is cooled down, thereby increasing relative humidity (RH) of the ambient air. Cold air exiting the radiator element 350, at the output port 362, is then fed to the adsorbent part AD of the adsorber unit 10’, i.e. to each adsorbent section AD of the adsorber unit 10’, to cause adsorption of water contained in the cold air. Water molecules are thus captured by the relevant adsorbent sections AD for future release during a subsequent desorption cycle. A suitable air circuit 200 is provided to ensure channelling of the ambient air, as schematically shown in Figure 2 (see also Figure 4), which air circuit 200 connects the input port 361 of the radiator element 350 to the ambient air intake and connects the output port 362 of the radiator element 350 to the relevant adsorbent sections AD. In effect, the radiator channels 360 accordingly form an integral part of the relevant air circuit 200. Ambient air is drawn and channelled through the air circuit 200 by any suitable means, including a fan or blower (not shown) coupled to the air circuit 200. As schematically shown in Figure 2, the air circuit 200 preferably further comprises an exhaust section to allow dehumidified air exiting the adsorbent part AD of the adsorber unit 10’ to be released into the environment.

Moist ambient air from which water is to be harvested is thus circulated through each of the adsorbent sections AD during the adsorption cycle by means of the air circuit 200. Besides the fan or blower (not shown), the air circuit 200 may also advantageously be provided with a particle filter (such as High Efficiency Particulate Air - HEPA - filters) used to filter moist ambient air from any undesired dust or impurity to avoid clogging and contamination of the adsorbent material. It will be appreciated that the relevant direction in which ambient air circulates through the adsorbent sections AD is not critical and does not impact adsorption efficiency.

One will appreciate that the adsorber unit 10 is similarly configured to channel ambient air, during an adsorption cycle, through the radiator channels 360 of the associated radiator element 350 and then through the adsorbent part AD of the adsorber unit 10. The relevant air circuit associated to the adsorber unit 10 is not shown in Figure 2 as it plays no role during the desorption cycle. In that regard, the same ambient air intake (and fan or blower arrangement) may be used to feed ambient air alternately through one or the other radiator element 350 depending on which adsorber unit 10 or 10’ undergoes the adsorption cycle. In such case, a suitable valve would be provided to direct airflow from the ambient air intake to the relevant one of the radiator element 350.

In the operating mode illustrated in Figure 2, thermal energy is transferred from the hot side HS of the thermoelectric element 30, via the thermally conductive bridge structure 380, to the adsorbent part AD of the adsorber unit 10. More specifically, thermal energy is transferred to the adsorbent section of the first adsorber stage 21. At the same time, the cooling stage CL that is thermally coupled to the vapor chamber VC of the last adsorber stage 24 is operated to draw heat away from the adsorber unit 10. As a result, water that had previously been adsorbed into the adsorbent section AD desorbs as water vapor into the adjacent vapor chamber VC where it is caused to condense into condensate, namely, on a side of the vapor chamber VC that is proximate to the adsorbent section AD of the following adsorber stage 22. In the illustrated embodiment, latent heat released as a result of condensation of the water vapor is advantageously transferred to the adsorbent section AD of the second adsorber stage 22 to sustain desorption therein. This process repeats itself in each of the following adsorber stages 23 and 24. In other words, latent heat resulting from condensation of the water vapor in each vapor section VC is recovered to efficiently re-heat the adsorbent material located in the following adsorbent sections AD. Such heat recovery is particularly advantageous in that this lowers thermal energy consumption, thereby improving energy usage efficiency. As shown in Figure 2 (see also Figure 4), the adsorber unit 10 is provided with a discharge circuit 250 that is coupled, in the illustrated example, to each of the vapor chambers VC of the adsorber unit 10, to recover the condensate resulting from condensation of the water vapor. In that regard, each of the vapor chambers VC may especially be provided with a drainage port to allow drainage by gravity of the condensate produced during the desorption phase. Such condensate can conveniently be collected in a suitable tank or reservoir (not shown) for use as potable water after remineralization.

One will appreciate that the adsorber unit 10’ is similarly configured to cause desorption of water vapor from the adsorbent sections AD, during a desorption cycle, and condensation thereof in the adjacent vapor chambers VC for recovery and collection of the resulting condensate. The relevant discharge circuit associated to the adsorber unit 10’ is not shown in Figure 2 as it plays no role during the adsorption cycle. In that regard, a common water collection tank or reservoir can be provided to collect condensate produced by one or the adsorber unit 10 or 10’ that undergoes the desorption cycle. Distinct water collection tanks or reservoirs could however be contemplated to separately collect the condensate from each adsorber unit 10, 10’.

Turning to Figures 3A-C and 4, one will now describe a particularly preferred embodiment of the thermoelectric device 30 and associated heat exchangers 35A, 35B depicted in Figures 1A-B and 2.

As shown in Figures 3A-B (see also Figure 4), each heat exchanger 35A, 35B preferably consists of a manifold radiator element 350 made e.g. of copper (or any other material exhibiting good thermal conductivity) having a generally parallelepipedal shape with first and second lateral sides (or “outer radiator sides”) 350A, 350B and a plurality of mini-channels 360 extending vertically from a bottom side 361 acting as input port to a top side 362 acting as output port, which mini-channels 360 are used to channel and pre-cool ambient air during the adsorption cycle, as explained above. The radiator element 350 is further provided with a plurality of, namely six pairs of heat conducting pipes 380 that are designed to act as thermally conductive bridge between the first and second outer radiator sides 350A, 350B. In the illustrated example, the heat conducting pipes 380 extend around both flanks of the radiator element 350. The heat pipes 380 are grouped in six pairs and extend from six corresponding locations on the first outer radiator side 350A, as shown in Figures 3A and 3B, that are each designed to receive one side of a corresponding Peltier element 300 for thermal coupling therewith. It will obviously be understood that this particular arrangement is purely illustrative and that the number of Peltier elements 300 and associated groups of heat pipes 380 could vary, without departing from the scope of the invention as defined by the appended claims.

In the illustrated example, both of the heat exchangers 35A, 35B exhibit the same configuration, as shown in Figures 3A-B, and the Peltier elements 300 are in effect sandwiched between the heat exchangers 35A, 35B as shown in Figure 3C, to form a same assembly that is positioned between the two adsorber units 10, 10’, as shown in Figure 4. A heat trench 350a is preferably further provided on the first outer radiator side 350A of each heat exchanger 35A, 35B, as shown in Figures 3A-B, to prevent or at least reduce thermal conduction loss between the heat exchangers 35A, 35B.

Figure 5 is a partial explanatory diagram illustrating operation of another embodiment of an AWGS comprising an adsorber unit 10* whose desorption cycle is driven by an electrically-powered heating device HT in accordance with a second aspect of the invention. In other words, the electrically-powered heating device HT acts as heating stage of the relevant adsorber unit 10* to drive desorption therein.

The configuration of the adsorber unit 10* shown schematically in Figure 5 is in effect similar to that of each of the adsorber units 10, 10’ discussed with reference to Figures 1A-B to 4, the same reference signs designating the same components and functions. In that regard, it is to be appreciated that the previously described thermoelectric device 30 in effect also forms a possible example of the electrically-operated heating device HT that is used to drive the desorption process in one or the other adsorber units 10, 10’ of Figures 1A-B to 4, depending on which side 30A, 30B of the thermoelectric device 30 is turned into the hot side HS. The electrically-operated heating device HT may consist of any other suitable type of electrical heater device, including especially a silicon heater (see e.g. Figures 6A-C), a cartridge heater (see e.g. Figures 7A-B) or a ceramic heater.

While not shown in Figure 5, it will be understood that the adsorber unit 10* much like the adsorber units 10, 10’ of Figures 1A-B to 4 is likewise coupled to an air circuit (as shown e.g. in Figures 2 and 4) that is configured to allow ambient air to be drawn into and channelled through each adsorbent section AD, when the adsorber unit 10* is operated to undergo the adsorption cycle, to cause adsorption of water contained in the ambient air. Similarly, this air circuit is likewise preferably further configured to allow dehumidified air exiting each adsorbent section AD of the adsorber unit 10*, when operated in the adsorption cycle, to be rejected into the environment.

As shown in Figure 5, the adsorber unit 10* is also preferably provided with a discharge circuit 250 that is coupled to each of the vapor chambers VC of the adsorber unit 10*, to recover the condensate resulting from condensation of the water vapor during the desorption cycle. This discharge circuit 250 can likewise suitably feed the condensate to a water collection reservoir (not shown).

Figures 6A-B are schematic, partially exploded perspective views of a silicon heater 40 with integral adsorbent structure AD (see also Figure 6C) shown from two different viewing angles, which silicon heater 40 is usable as electrically- powered heating device HT of the AWGS of Figure 5. In the illustrated example, the silicon heater 40 is thermally coupled to a heat transfer structure 45, preferably via an adhesive layer made of thermal interface material TIM, to act as heating stage of the adsorber unit 10*.

More specifically, in the illustrated example, the assembly including the combination of the silicon heater 40 and heat transfer structure 45 advantageously further integrates the adsorbent section AD of the first adsorber stage 21 of the adsorber unit 10*. In that regard, an adsorbent structure 450 is formed on a side 45A of the heat transfer structure 45 opposite to the side to which the silicon heater 40 is thermally coupled. The adsorbent structure 450 may advantageously consist of a coating or layer made of solid adsorbent material that is formed directly onto the side 45A of the heat transfer structure 45.

By way of preference, the heat transfer structure 45 is provided with integral input and output ports 451 , 452 (see also Figure 6C) to channel airflow to and from the adsorbent structure 450. Even more preferably, as more clearly visible in Figure 6C, the adsorbent structure 450 is structured to form a plurality of longitudinal channels or grooves 450a to increase exposure to airflow during the adsorption cycle, as well as increase desorption efficiency during the desorption cycle.

Figure 7A is a schematic, partially exploded perspective view of a cartridge heater 50 with integral adsorbent structure AD (see also Figure 7C), which cartridge heater 50 is usable as electrically-powered heating device HT of the AWGS of Figure 5. In the illustrated example, the cartridge heater 50 include five cartridge heating elements 500 that are inserted (see Figure 7B) into a corresponding number of sockets 510A of the cartridge heater 50. The sockets 510A may be formed on a side of a heater plate 510 that is thermally coupled to a heat transfer structure 55 to act as heating stage of the adsorber unit 10*. Much like the silicon heater 40 of Figures 6A-C, the heater plate 510 could be coupled thermally to the heat transfer structure 55 via an adhesive layer made of thermal interface material TIM (not shown).

More specifically, in the illustrated example, the assembly including the combination of the cartridge heater 50 and heat transfer structure 55 advantageously further integrates the adsorbent section AD of the first adsorber stage 21 of the adsorber unit 10*. In that regard, an adsorbent structure 550 is likewise formed on a side 55A of the heat transfer structure 55 opposite to the side to which the heater plate 510 is thermally coupled. Much like the previously described adsorbent structure 450, the adsorbent structure 550 may advantageously consist of a coating or layer made of solid adsorbent material that is formed directly onto the side 55A of the heat transfer structure 55.

By way of preference, the heat transfer structure 55 is similarly provided with integral input and output ports 551 , 552 to channel airflow to and from the adsorbent structure 550. Even more preferably, the adsorbent structure 550 is likewise structured to form a plurality of longitudinal channels or grooves 550a to increase exposure to airflow during the adsorption cycle, as well as increase desorption efficiency during the desorption cycle.

The adsorbent material forming the adsorbent sections AD of the adsorber units 10, 10’, 10* may be any suitable adsorbent material, including e.g. packed silica gel or zeolites. Other adsorbent materials could however be contemplated, including the adsorbent materials identified in the preamble hereof.

During desorption, the adsorbent sections AD are brought to a temperature sufficient to cause vaporization of the water (typically to a temperature of approximately 80°C to 90°C or higher for enhanced regeneration/desorption).

In some embodiments, the adsorbent sections AD could consist of adsorbent beds containing an adsorbent material, which adsorbent bed is coupled to the adjacent vapor chamber VC via a vapor permeable separation wall, such as but not limited to a perforated plate, a vapor permeable membrane or mesh. In other embodiments, the adsorbent sections AD could consist of a coated adsorbent layer formed on a side of a suitable heat transfer plate or structure (much like the previously described adsorbent structures 450, 550) in the adjacent vapor chamber VC, in which case no vapor permeable separation wall is required. In that regard, the various considerations set forth in International (PCT) Application No. PCT/IB2021/059253 mentioned in the preamble hereof regarding the configuration of the adsorbent structures apply by analogy and could be implemented in the context of the present invention. The invention is not limited to any specific configuration of the adsorbent sections AD and adjacent vapor chambers VC, which may be constructed in any adequate manner to ensure suitable performance of the relevant adsorption and desorption cycles.

Various modifications and/or improvements may be made to the abovedescribed embodiments without departing from the scope of the invention as defined by the appended claims.

For instance, the first aspect of the invention discussed with reference to Figures 1 A-B to 4 could be applied irrespective of the actual configuration of the first and second adsorber units 10, 10’. This being said, a multi-stage configuration as described provides clear benefits in that this solution improves desorption efficiency by recovering latent heat resulting from condensation of the water vapor in each vapor section VC to heat the adsorbent material located in the following adsorbent sections AD.

LIST OF REFERENCE NUMERALS AND SIGNS USED THEREIN

10 (first) adsorber unit

10’ (second) adsorber unit

10* adsorber unit

21 -24 (first to fourth) adsorber stages of adsorber unit 10, 10’, resp. 10*

AD adsorbent section of each adsorber stage 21-24 I adsorbent part of adsorber unit 10, 10’, resp. 10*

VC vapor chamber of each adsorber stage 21 -24, adjacent adsorbent section AD I vapor chamber part of adsorber unit 10, 10’, resp. 10*

HT electrically-operated heating device acting as heating stage of adsorber unit 10, 10’, resp. 10*

CL cooling stage of adsorber unit 10, 10’, resp. 10*

30 thermoelectric device I electrically-operated heating device

30A first side of thermoelectric device 30 that is thermally coupled to the first adsorber unit 10

30B second side of thermoelectric device 30 that is thermally coupled to the second adsorber unit 10’

CS cold side of thermoelectric device 30 (first or second side 30A, 30B) HS hot side of thermoelectric device 30 (first or second side 30A, 30B) 35A, 35B heat exchanger I heat transfer structure

200 air circuit coupled to adsorbent part AD of adsorber unit 10, 10’, resp. 10* (feeding of ambient air during adsorption cycle) I air circuit coupled to input and output ports 361 , 362 of radiator element 350 (pre-cooling of ambient air during adsorption cycle)

250 discharge circuit coupled to vapor chamber part VC of adsorber unit 10, 10’, resp. 10* (recovery of condensate produced during desorption cycle)

300 Peltier elements sandwiched between heat exchangers 35A, 35B 350 radiator element (part of heat exchanger 35A, 35B)

350A first outer radiator side of radiator element 350 that is thermally coupled to first or second side 30A, 30B of thermoelectric device 30

350B second outer radiator side of radiator element 350 that is thermally coupled to first or second adsorber unit 10, 10’

350a heat trench provided on first outer radiator side 350A of radiator element 350

360 radiator channels extending longitudinally through radiator element 30 between input and output ports 361 , 362

361 input port 361 (coupled to ambient air intake)

362 output port 362 (coupled to adsorbent part AD of adsorber unit 10, resp. 10’)

380 thermally conductive bridge between first and second outer radiator sides 350A, 350B I plurality of heat pipes extending front the first outer radiator side 350A (in thermal contact with Peltier elements 300) to the second outer radiator side 350B around flanks of the radiator element 350

40 silicon heater / electrically-operated heating device

45 heat transfer structure thermally coupled to silicon heater 40

45A side of heat transfer structure 45 opposite to side to which silicon heater 40 in thermally coupled

450 adsorbent structure formed on side 45A of heat transfer structure 45 (adsorbent section AD of first adsorber stage 21 ) I adsorbent coating or layer

450a longitudinal channels or grooves formed on adsorbent structure 450

451 input port of heat transfer structure 45 (coupled to ambient air intake)

452 output port of heat transfer structure 45 (release of dehumidified air)

50 cartridge heater I electrically-operated heating device

55 heat transfer structure thermally coupled to cartridge heater 50

55A side of heat transfer structure 55 opposite to side to which cartridge heater 50 in thermally coupled

500 cartridge heating elements 510 heater plate of cartridge heater 50

510A sockets formed on one side of heater plate 510 to receive cartridge heating elements 500

550 adsorbent structure formed on side 55A of heat transfer structure 55 (adsorbent section AD of first adsorber stage 21 ) I adsorbent coating or layer

550a longitudinal channels or grooves formed on adsorbent structure 550

551 input port of heat transfer structure 55 (coupled to ambient air intake)

552 output port of heat transfer structure 55 (release of dehumidified air) TIM layer of thermal interface material

Claims

1. An atmospheric water generation system comprising first and second adsorber units (10, 10’) each configured to operate alternately in an adsorption cycle and in a desorption cycle, wherein the atmospheric water generation system further comprises a thermoelectric device (30) with a first side (30A) thermally coupled to the first adsorber unit (10) and a second side (30B) thermally coupled to the second adsorber unit (10’), wherein the thermoelectric device (30) is operable such that one of the first and second sides (30A, 30B) of the thermoelectric device (30) is turned into a cold side (CS), while the other one of the first and second sides (30A, 30B) of the thermoelectric device (30) is turned into a hot side (HS), wherein the atmospheric water generation system is configured such that, in operation, the cold side (CS) of the thermoelectric device (30) is thermally coupled to that one of the first and second adsorber units (10, 1 O’) that undergoes the adsorption cycle, while the hot side (HS) of the thermoelectric device (30) is thermally coupled to that one of the first and second adsorber units (10, 10’) that undergoes the desorption cycle.

2. The atmospheric water generation system according to claim 1 , wherein the first and second sides (30A, 30B) of the thermoelectric device (30) are each thermally coupled to, respectively, the first and second adsorber units (10, 10’) via a corresponding heat exchanger (35A, 35B).

3. The atmospheric water generation system according to claim 2, wherein each of the first and second adsorber units (10, 10’) is thermally coupled to the associated heat exchanger (35A, 35B) via a layer of thermal interface material (TIM).

4. The atmospheric water generation system according to claim 2 or 3, wherein each heat exchanger (35A, 35B) includes a radiator element (350) comprising radiator channels (360) extending longitudinally through the radiator element (350) to channel airflow from an input port (361 ) to an output port (362).

5. The atmospheric water generation system according to claim 4, wherein the radiator element (350) comprises a first and second outer radiator sides (350A, 350B), the first outer radiator side (350A) being thermally coupled to the first side (30A) or the second side (30B) of the thermoelectric device (30), and the second outer radiator side (350B) being thermally coupled to, respectively, the first adsorber unit (10) or the second adsorber unit (10’), and wherein each heat exchanger (35A, 35B) further includes a thermally conductive bridge structure (380) thermally coupling the first outer radiator side (350A) to the second outer radiator side (350B).

6. The atmospheric water generation system according to claim 5, wherein the thermally conductive bridge structure includes a plurality of heat pipes (380) extending from the first outer radiator side (350A) to the second outer radiator side (350B) around flanks of the radiator element (350).

7. The atmospheric water generation system according to any one of claims 2 to 6, wherein the thermoelectric device (30) includes at least one Peltier element (300) that is sandwiched between the heat exchangers (35A, 35B).

8. The atmospheric water generation system according to claim 5 or 6, wherein the thermoelectric device (30) includes at least one Peltier element (300) that is sandwiched between the heat exchangers (35A, 35B) in order to be thermally coupled with the thermally conductive bridge structure (380).

9. The atmospheric water generation system according to claim 7 or 8, wherein a side (350A) of each heat exchanger (35A, 35B) against which the at least one Peltier element (300) is sandwiched is provided with a heat trench (350a) to prevent or reduce thermal conduction loss between the heat exchangers (35A, 35B). 10. The atmospheric water generation system according to any one of claims 4 to 6 and 8, wherein each adsorber unit (10, 10’) and each radiator element (350) are coupled to an air circuit (200) that is configured to allow ambient air to be drawn into and channelled through the radiator channels (360) of the radiator element (350) that, in operation, is thermally coupled to the cold side (CS) of the thermoelectric element (30) and to allow cold air exiting the radiator element (350) to be channelled through an adsorbent part (AD) of that one of the first and second adsorber units (10,

10’) that undergoes the adsorption cycle to cause adsorption of water contained in the cold air.

11. The atmospheric water generation system according to claim 10, wherein the air circuit (200) is further configured to allow dehumidified air exiting the adsorbent part (AD) of that one of the first and second adsorber units (10, 10’) that undergoes the adsorption cycle to be rejected into the environment.

12. The atmospheric water generation system according to claim 5, 6 or 8, wherein the atmospheric water generation system is configured such that, in operation, thermal energy is transferred from the hot side (HS) of the thermoelectric device (30), via the thermally conductive bridge structure (380), to an adsorbent part (AD) of that one of the first and second adsorber units (10, 10’) that undergoes the desorption cycle to cause water adsorbed into the adsorbent part (AD) to be desorbed as water vapor into an adjacent vapor chamber part (VC) of the adsorber unit (10, 10’).

13. The atmospheric water generation system according to any one of the preceding claims, wherein each adsorber unit (10, 10’) comprises a discharge circuit (250) that is configured to allow recovery of condensate resulting from condensation of water vapor occurring in that one of the first and second adsorber units (10, 10’) that undergoes the desorption cycle.

14. The atmospheric water generation system according to any one of the preceding claims, wherein the thermoelectric device (30) is operable such that a polarity thereof can be reversed to switch the cold side (CS) and the hot side (HS), and thus switch the first and second adsorber units (10, 10’) to undergo the other one of the adsorption and desorption cycles.

15. The atmospheric water generation system according to any one of the preceding claims, wherein each of the first and second adsorber units (10, 10’) includes a plurality of successive adsorber stages (21 , 22, 23, 24) each including an adsorbent section (AD) coupled to an adjacent vapor chamber (VC) to allow vapor transfer thereto, wherein the thermoelectric device (30) is thermally coupled to the adsorbent section (AD) of a first one (21 ) of the adsorber stages (21 , 22, 23, 24), wherein the adsorbent section (AD) of each subsequent one (22, 23, 24) of the adsorber stages (21 , 22, 23, 24) is thermally coupled to the vapor chamber (VC) of the preceding adsorber stage (21 , 22, 23) to allow transfer of thermal energy between the adsorber stages (21 , 22, 23, 24), and wherein each of the first and second adsorber units (10, 10’) further includes a cooling stage (CL) that is thermally coupled to the vapor chamber (VC) of a last one (24) of the adsorber stages (21 , 22, 23, 24).

16. The atmospheric water generation system according to claim 15, wherein each of the first and second adsorber units (10, 10’) is configured such that, when operated in the desorption cycle, water adsorbed into the adsorbent section (AD) of the first adsorber stage (21 ) is caused to desorb as water vapor into the adjacent vapor chamber (VC) of the first adsorber stage (21 ) and latent heat released as a result of condensation of the water vapor is transferred to the adsorbent section (AD) of a second one (22) of the adsorber stages (21 , 22, 23, 24) to sustain desorption in the second adsorber stage (22) and, if applicable, each subsequent one (23, 24) of the adsorber stages (21 , 22, 23, 24).

17. An atmospheric water generation system comprising an adsorber unit (10; 10’; 10*) configured to operate alternately in an adsorption cycle and in a desorption cycle, wherein the atmospheric water generation system further comprises an electrically-powered heating device (HT) that is thermally coupled to the adsorber unit (10; 10’; 10*), wherein the adsorber unit (10; 10’; 10*) includes a plurality of successive adsorber stages (21 , 22, 23, 24) each including an adsorbent section (AD) coupled to an adjacent vapor chamber (VC) to allow vapor transfer thereto, wherein the electrically-powered heating device (HT) is thermally coupled to the adsorbent section (AD) of a first one (21 ) of the adsorber stages (21 , 22, 23, 24) to selectively supply thermal energy thereto, wherein the adsorbent section (AD) of each subsequent one (22, 23, 24) of the adsorber stages (21 , 22, 23, 24) is thermally coupled to the vapor chamber (VC) of the preceding adsorber stage (21 , 22, 23) to allow transfer of thermal energy between the adsorber stages (21 , 22, 23, 24), wherein the adsorber unit (10; 10’; 10*) further includes a cooling stage (CL) that is thermally coupled to the vapor chamber (VC) of a last one (24) of the adsorber stages (21 , 22, 23, 24), and wherein the electrically-powered heating device (HT) is powered to operate the adsorber unit (10; 10’; 10*) in the desorption cycle and supply thermal energy to the adsorbent section (AD) of the first adsorber stage (21 ) to drive desorption of water adsorbed into the adsorbent sections (AD) of the adsorber unit (10; 10’; 10*).

18. The atmospheric water generation system according to claim 17, wherein the adsorber unit (10; 10’; 10*) is configured such that, when operated in the desorption cycle, water adsorbed into the adsorbent section (AD) of the first adsorber stage (21 ) is caused to desorb as water vapor into the adjacent vapor chamber (VC) of the first adsorber stage (21 ) and latent heat released as a result of condensation of the water vapor is transferred to the adsorbent section (AD) of a second one (22) of the adsorber stages (21 , 22, 23, 24) to sustain desorption in the second adsorber stage (22) and, if applicable, each subsequent one (23, 24) of the adsorber stages (21 , 22, 23, 24).

19. The atmospheric water generation system according to claim 17 or 18, wherein the electrically-powered heating device (HT) is a silicon heater (40).

20. The atmospheric water generation system according to claim 17 or 18, wherein the electrically-powered heating device (HT) is a cartridge heater (50).

21. The atmospheric water generation system according to claim 20, wherein the cartridge heater (50) includes a plurality of cartridge heating elements (500) that are inserted into a corresponding number of sockets (510A) of the cartridge heater (50).

22. The atmospheric water generation system according to claim 17 or 18, wherein the electrically-powered heating device (HT) is a ceramic heater.

23. The atmospheric water generation system according to any one of claims 17 to 22, wherein the electrically-powered heating device (HT) is thermally coupled to the adsorber unit (10; 10’; 10*) via a layer of thermal interface material (TIM).

24. The atmospheric water generation system according to any one of claims 17 to 23, wherein the electrically-powered heating device (HT) is thermally coupled to a heat transfer structure (35A, 35B; 45; 55) to act as heating stage of the adsorber unit (10; 10’; 10*).

25. The atmospheric water generation system according to claim 24, wherein the adsorbent section (AD) of the first adsorber stage (21 ) includes an adsorbent structure (450; 550) that is formed on a side (45A; 55A) of the heat transfer structure (45; 55) opposite to a side to which the electrically-powered heating device (HT) is thermally coupled.

26. The atmospheric water generation system according to claim 25, wherein the adsorbent structure (450; 550) consists of a coating or layer made of adsorbent material that is formed directly onto the side (45A; 55A) of the heat transfer structure (45; 55).

27. The atmospheric water generation system according to claim 25 or 26, wherein the heat transfer structure (45; 55) is provided with integral input and output ports (451 , 452; 551 , 552) to channel airflow to and from the adsorbent structure (450; 550).

28. The atmospheric water generation system according to claim 27, wherein the adsorbent structure (450; 550) is structured to form a plurality of longitudinal channels or grooves (450a; 550a) to increase exposure to airflow.

29. The atmospheric water generation system according to any one of claims 17 to 28, wherein the adsorber unit (10; 10’; 10*) is coupled to an air circuit (200) that is configured to allow ambient air to be drawn into and channelled through each adsorbent section (AD), when the adsorber unit (10; 10’; 10*) is operated to undergo the adsorption cycle, to cause adsorption of water contained in the ambient air.

30. The atmospheric water generation system according to claim 29, wherein the air circuit (200) is further configured to allow dehumidified air exiting each adsorbent section (AD) of the adsorber unit (10; 10’; 10*), when operated in the adsorption cycle, to be rejected into the environment.

31 . The atmospheric water generation system according to any one of claims 15 to 30, wherein the plurality of successive adsorber stages (21 , 22, 23, 24) includes a sequence of n adsorber stages (21 , 22, 23, 24), n being an integer number ranging from 2 to 10.

32. An atmospheric water generation method comprising:

(a) providing first and second adsorber units (10, 10’) each configured to operate alternately in an adsorption cycle and in a desorption cycle;

(b) providing a thermoelectric device (30) having first and second sides (30A, 30B);

(c) thermally coupling the first side (30A) of the thermoelectric device (30) to the first adsorber unit (10) and the second side (30B) of the thermoelectric device (30) to the second adsorber unit (10’);

(d) operating the thermoelectric device (30) to turn one of the first and second sides (30A, 30B) of the thermoelectric device (30) into a cold side (CS), while the other one of the first and second sides (30A, 30B) of the thermoelectric device (30) is turned into a hot side (HS); and

(e) recovering condensate resulting from condensation of water vapor occurring in that one of the first and second adsorber units (10, 10’) that undergoes the desorption cycle, wherein that one of the first and second adsorber units (10, 10’) that is thermally coupled to the cold side (CS) of the thermoelectric device (30) undergoes the adsorption cycle, while that one of the first and second adsorber units (10, 10’) that is thermally coupled to the hot side (HS) of the thermoelectric device (30) undergoes the desorption cycle.

33. The atmospheric water generation method according to claim 32, wherein step (c) includes coupling each of the first and second sides (30A, 30B) of the thermoelectric device (30) to, respectively the first and second adsorber units (10, 10’) via a heat exchanger (35A, 35B).

34. The atmospheric water generation method according to claim 33, wherein each heat exchanger (35A, 35B) includes a radiator element (350) comprising radiator channels (360) extending longitudinally through the radiator element (350) to channel airflow from an input port (361 ) to an output port (362), and wherein the method further comprises feeding ambient air through the radiator channels (360) of the radiator element (350) that is thermally coupled to the cold side (CS) of the thermoelectric element (30) and channelling cold air exiting the radiator element (350) through an adsorbent part (AD) of that one of the first and second adsorber units (10, 10’) that undergoes the adsorption cycle to cause adsorption of water contained in the cold air.

35. The atmospheric water generation method according to claim 34, further comprising releasing dehumidified air exiting the adsorbent part (AD) of that one of the first and second adsorber units (10, 10’) that undergoes the adsorption cycle into the environment.

36. The atmospheric water generation method according to claim 34 or 35, further comprising transferring thermal energy from the hot side (HS) of the thermoelectric device (30), across the radiator element (350), to an adsorbent part (AD) of that one of the first and second adsorber units (10, 10’) that undergoes the desorption cycle to cause water adsorbed into the adsorbent part (AD) to be desorbed as water vapor into an adjacent vapor chamber part (VC) of the adsorber unit (10, 10’).

37. The atmospheric water generation method according to any one of claims 32 to 36, wherein step (d) includes periodically reversing a polarity of the thermoelectric device (30) to switch the cold side (CS) and the hot side (HS), and thus switch the first and second adsorber units (10, 10’) to undergo the other one of the adsorption and desorption cycles.

38. The atmospheric water generation method according to any one of claims 32 to 37, wherein each of the first and second adsorber units (10, 10’) includes two or more successive adsorber stages (21 , 22, 23, 24) each including an adsorbent section (AD) coupled to an adjacent vapor chamber (VC) to allow vapor transfer thereto, wherein step (c) includes thermally coupling the thermoelectric device (30) to the adsorbent section (AD) of a first one (21 ) of the adsorber stages (21 , 22, 23, 24), wherein the adsorbent section (AD) of each subsequent one (22, 23, 24) of the adsorber stages (21 , 22, 23, 24) is thermally coupled to the vapor chamber (VC) of the preceding adsorber stage (21 , 22, 23) to allow transfer of thermal energy between the adsorber stages (21 , 22, 23, 24), wherein the thermoelectric device (30) is operated at step (d) to transfer thermal energy from the hot side (HS) of the thermoelectric device (30) to the adsorbent sections (AD) of that one of the first and second adsorber units (10, 10’) that undergoes the desorption cycle to cause water adsorbed in the adsorbent sections (AD) to be desorbed into water vapor, which water vapor transits to the adjacent vapor chambers (VC), and wherein step (e) includes condensing the water vapor contained in the vapor chambers (VC) into the condensate.

39. An atmospheric water generation method comprising:

(a) providing an adsorber unit (10; 10’; 10*) configured to operate alternately in an adsorption cycle and in a desorption cycle, wherein the adsorber unit (10; 10’; 10*) includes two or more successive adsorber stages (21 , 22, 23, 24) each including an adsorbent section (AD) coupled to an adjacent vapor chamber (VC) to allow vapor transfer thereto;

(b) providing an electrically-powered heating device (HT);

(c) thermally coupling the electrically-powered heating device (HT) to the adsorbent section (AD) of a first one (21 ) of the adsorber stages (21 , 22, 23, 24), wherein the adsorbent section (AD) of each subsequent one (22, 23, 24) of the adsorber stages (21 , 22, 23, 24) is thermally coupled to the vapor chamber (VC) of the preceding adsorber stage (21 , 22, 23) to allow transfer of thermal energy between the adsorber stages (21 , 22, 23, 24);

(d) selectively operating the electrically-powered heating device (HT) to supply thermal energy to the adsorbent sections (AD) of the adsorber unit (10; 10’; 10*) to undergo the desorption cycle and cause water adsorbed in the adsorbent sections (AD) to be desorbed into water vapor, which water vapor transits to the adjacent vapor chambers (VC); and

(e) condensing the water vapor contained in the vapor chambers (VC) into a condensate when the adsorber unit (10; 10’; 10*) is being operated to undergo the desorption cycle.

40. The method according to claim 39, wherein step (c) includes coupling the electrically-powered heating device (HT) to the adsorber unit (10; 10’; 10*) via a heat transfer structure (35A; 35B; 45; 55) to act as heating stage of the adsorber unit (10; 10’; 10*).

41 . The method according to claim 40, including forming an adsorbent structure (450; 550) on a side (45A; 55A) of the heat transfer structure (45; 55) opposite to a side to which the electrically-powered heating device (HT) is thermally coupled.

42. The method according to claim 41 , including forming a coating or layer made of adsorbent material directly onto the side (45A; 55A) of the heat transfer structure (45; 55).

43. The method according to claim 41 or 42, further comprising the step of feeding and channelling ambient air through the heat transfer structure (45; 55) when the adsorber unit (10*) is being operated to undergo the adsorption cycle to cause adsorption by the adsorbent structure (450; 550) of water contained in the ambient air.

44. The method according to claim 43, further including structuring the adsorbent structure (450; 550) to form a plurality of longitudinal channels or grooves (450a; 550a) to channel airflow.

45. The method according to any one of claims 39 to 44, wherein step (b) includes providing a silicon heater (40), a cartridge heater (50) or a ceramic heater as the electrically-powered heating device (HT).

46. The method according to any one of claim 39 or 40, wherein step (b) includes providing a thermoelectric device (30) as the electrically-powered heating device (HT), which thermoelectric device (30) is operable such that a side (30A; 30B) of the thermoelectric device (30) that is thermally coupled to the adsorber unit (10; 10’) is turned into a cold side (CS) or a hot side (HS), wherein step (d) includes operating the thermoelectric device (30) to turn the side (30A; 30B) of the thermoelectric device (30) that is thermally coupled to the adsorber unit (10; 10’) to the hot side (HS), and wherein the thermoelectric device (30) is selectively operated to turn the side (30A; 30B) of the thermoelectric device (30) that is thermally coupled to the adsorber unit (10; 10’) to the cold side (CS) to cause the adsorber unit (10; 10’) to undergo the adsorption cycle.

47. The method according to claim 40, wherein step (b) includes providing a thermoelectric device (30) as the electrically-powered heating device (HT), which thermoelectric device (30) is operable such that a side (30A; 30B) of the thermoelectric device (30) that is thermally coupled to the adsorber unit (10; 10’) is turned into a cold side (CS) or a hot side (HS), wherein step (d) includes operating the thermoelectric device (30) to turn the side (30A; 30B) of the thermoelectric device (30) that is thermally coupled to the adsorber unit (10; 10’) to the hot side (HS), wherein the thermoelectric device (30) is selectively operated to turn the side (30A; 30B) of the thermoelectric device (30) that is thermally coupled to the adsorber unit (10; 10’) to the cold side (CS) to cause the adsorber unit (10; 10’) to undergo the adsorption cycle, and wherein, when operated in the adsorption cycle, ambient air is drawn into and channelled through channels (360) extending longitudinally through the heat transfer structure (35A; 35B) to be cooled and cold air exiting the channels (360) of the heat transfer structure (35A; 35B) is channelled through the adsorbent sections (AD) of the adsorber unit (10; 10’) to cause adsorption of water contained in the cold air.

48. The atmospheric water generation method according to any one of claims 38 to 47, wherein latent heat resulting from condensation of the water vapor generated by a preceding adsorber stage (21 , 22, 23) is transferred to the adsorbent section (AD) of a following adsorber stage (22, 23, 24) to sustain desorption.

49. The method according to any one of claims 38 to 48, wherein step (a) includes providing a sequence of n adsorber stages (21 , 22, 23, 24), n being an integer number ranging from 2 to 10.