WO2025054657A1

WO2025054657A1 - Carbon dioxide capture systems, methods and apparatus

Info

Publication number: WO2025054657A1
Application number: PCT/AU2024/050971
Authority: WO
Inventors: Julian TURECEK; Ian SCHIRMER
Original assignee: AspiraDAC Pty Ltd
Priority date: 2023-09-12
Filing date: 2024-09-11
Publication date: 2025-03-20

Abstract

The apparatus comprises at least one enclosure, a temperature control system and a pressure control system both coupled to the at least one enclosure. The temperature control system controls a temperature within the enclosure whilst the pressure control system controls a pressure within the enclosure. The enclosure also comprises an adsorbent material inside the enclosure capable of adsorbing CO2, an intake to communicate air into the enclosure and an exhaust to communicate gasses out of the enclosure. The temperature control system and/or the pressure control system are adjustable to cause the adsorbent material to adsorb CO2 from air drawn into the enclosure, reduce the pressure and increase the temperature in the enclosure to cause the adsorbent material to release the adsorbed CO2 and recycle one or more of heat energy and vacuum energy in the enclosure for subsequent adsorption of CO2 by the adsorbent material from air drawn into the enclosure.

Description

TITLE

CARBON DIOXIDE CAPTURE SYSTEMS, METHODS AND APPARATUS

FIELD OF THE INVENTION

The present invention relates to carbon dioxide capture systems, methods and apparatus. In particular, the present invention relates to direct air capture systems, methods and apparatus for removing carbon dioxide from the atmosphere.

BACKGROUND

Direct air capture (DAC) is a method of extracting molecules from the air using an adsorbent material which has an affinity for those molecules. In the case of carbon capture, the molecules are carbon dioxide (CO2). The direct air capture process has two main states - the adsorption state and the desorption state. During the adsorption state air is directed across the adsorbent material and the molecules of interest bond to the adsorbent material releasing energy. This energy is often referred to the isoteric heat of adsorption/desorption (Qst) representing all the energy necessary to bind the molecules of interest to and release the molecules of interest from the adsorbent material.

During the desorption phase the environment surrounding the adsorbent material is changed so that the molecules of interest are released from the adsorbent material, and in the process adsorb the Qst energy. The desorption phase is carried out at a gas pressure of near zero absolute, and by adding heat at the temperature which causes the molecules of interest to disassociate from the adsorbent material. This process is commonly referred to as temperature vacuum swing adsorption (TVSA). This process is similar to the process of boiling water in that at a particular temperature and pressure water molecules disassociate from the liquid and become gas, and in the process require latent heat energy to release the water-water bond. One problem with existing direct air capture methods and apparatus is the high energy consumption required to capture the carbon dioxide. Some current methods and apparatus use inefficient methods of heating to change and maintain the environments for desorption and they also exhaust waste heat to the atmosphere. Such inefficiency renders such methods and apparatus unfeasible, particularly on the scale required to reduce CO2 levels in the atmosphere.

Where the energy required for the TVSA DAC process is sourced from renewables, the overall process becomes more competitive in terms of associated emissions relative to carbon dioxide captured, but significant improvements are still required, particularly for large scale implementation.

The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that the prior art forms part of the common general knowledge in the art.

OBJECT OF THE INVENTION

It is a preferred object of the present invention to provide a carbon dioxide capture system and/or a carbon dioxide capture method and/or a carbon dioxide capture apparatus that addresses or at least ameliorates one or more of the aforementioned problems and/or provides a useful commercial alternative.

In particular, it is a preferred object of the present invention to provide a direct air capture (DAC) system and/or method and/or apparatus to remove carbon dioxide from the atmosphere that has significantly lower energy consumption than at least some of the prior art DAC systems, methods and/or apparatus.

SUMMARY OF THE INVENTION

Generally, embodiments of the present invention are directed to direct air capture systems, methods and apparatus for removing carbon dioxide from the atmosphere. According to one aspect, but not necessarily the broadest or the only aspect, the present invention is directed to a direct air capture (DAC) apparatus to remove carbon dioxide (CO2) from the atmosphere, the apparatus comprising: one or more enclosures having an adsorbent material inside the one or more enclosures capable of adsorbing CO2; a temperature control system and a pressure control system coupled to the one or more enclosures to control adsorption and desorption of CO2 by the adsorbent material; and wherein at least some heat energy and/or at least some vacuum energy in the one or more enclosures resulting from desorption of the CC from the adsorbent material is recycled for subsequent adsorption of CO2 by the adsorbent material.

Preferably, the temperature control system comprises at least a heat exchanger, a compressor and one or more valves coupled to the one or more enclosures.

Preferably, the pressure control system comprises at least a vacuum pump, a compressor and one or more valves coupled to the one or more enclosures.

According to another aspect, but not necessarily the broadest or the only aspect, the present invention is directed to a direct air capture (DAC) apparatus to remove carbon dioxide (CO2) from the atmosphere, the apparatus comprising: at least one enclosure comprising: an adsorbent material inside the enclosure capable of adsorbing CO2; an intake to communicate air into the enclosure; and an exhaust to communicate gasses out of the enclosure; a temperature control system coupled to the at least one enclosure to control a temperature within the enclosure; and a pressure control system coupled to the at least one enclosure to control a pressure within the enclosure; wherein the temperature control system and/or the pressure control system are adjustable to: cause the adsorbent material to adsorb CO2 from air drawn into the enclosure; reduce the pressure and increase the temperature in the enclosure to cause the adsorbent material to release the adsorbed CO2; and recycle at least some heat energy and/or at least some vacuum energy in the enclosure for subsequent adsorption of CO2 by the adsorbent material from air drawn into the enclosure.

In some embodiments, the apparatus comprises at least two enclosures coupled together and one or more of the heat energy and the vacuum energy is recycled between the at least two enclosures.

In some embodiments, the apparatus comprises three or more enclosures coupled together, wherein one or more of the heat energy and the vacuum energy is recycled between the three or more enclosures. In such embodiments, desorption of the adsorbed CC from the adsorbent material occurs in at least two of the enclosures whilst the adsorbent material adsorbs CO2 in at least another one of the enclosures.

Suitably, air is drawn into the at least one enclosure to reduce the temperature of the at least one enclosure after desorption of the adsorbed CC from the adsorbent material and before adsorption of CO2 by the adsorbent material recommences in the same enclosure.

Suitably, the temperature control system comprises at least a heat pump and a heat exchanger coupled to the at least one enclosure.

Suitably, the pressure control system comprises at least a vacuum pump and one or more valves coupled to the at least one enclosure.

Suitably, the apparatus further comprise a controller coupled to the temperature control system and the pressure control system to coordinate control of the temperature and the pressure in the at least one enclosure. Suitably, the adsorbent material is housed in a cartridge within the enclosure.

Suitably, the adsorbent material is a metal organic framework (MOF), but other adsorbent materials could be used.

The apparatus may further comprise a power source coupled to the temperature control system and the pressure control system selected from the following: one or more solar panels; one or more batteries; a utility power supply; another renewable power source, such as wind power.

Preferably, the air drawn into the enclosure is at ambient temperature and atmospheric pressure.

Preferably, the temperature control system and/or the pressure control system are adjustable to maximize adsorption of CO2 from the air by the adsorbent material.

According to another aspect, the present invention is directed to a system to remove carbon dioxide (CO2) from the atmosphere comprising a plurality of the aforementioned direct air capture (DAC) apparatus coupled together.

According to a further aspect, the present invention is directed to a method of removing carbon dioxide (CO2) from the atmosphere with a direct air capture (DAC) apparatus, the apparatus comprising: at least one enclosure comprising: an adsorbent material capable of adsorbing CO2; an intake to communicate air into the enclosure; and an exhaust to communicate gasses out of the enclosure; a temperature control system coupled to the at least one enclosure to control a temperature within the enclosure; and a pressure control system coupled to the at least one enclosure to control a pressure within the enclosure; and the method including adjusting the temperature control system and/or the pressure control system to: cause the adsorbent material to adsorb CO2 from the air drawn into the enclosure; reduce the pressure and increase the temperature in the enclosure to cause the adsorbent material to release the adsorbed CO2; and recycle one or more of heat energy and vacuum energy in the enclosure for subsequent adsorption of CO2 by the adsorbent material.

According to a yet further aspect, the present invention is directed to a method of removing carbon dioxide (CO2) from the atmosphere with a direct air capture (DAC) apparatus, the method comprising: adjusting a temperature control system and/or a pressure control system to cause an adsorbent material in an enclosure to adsorb CO2 from air drawn into the enclosure; reducing the pressure and increasing the temperature in the enclosure to cause the adsorbent material to release the adsorbed CO2; and recycling one or more of heat energy and vacuum energy in the enclosure for subsequent adsorption of CO2 by the adsorbent material.

The methods may comprise recycling one or more of the heat energy and the vacuum energy between at least two enclosures coupled together.

The methods may comprise recycling one or more of the heat energy and the vacuum energy between three or more enclosures coupled together.

The methods may comprise causing desorption of the adsorbed CO2 from the adsorbent material to occur in at least two of the enclosures whilst causing the adsorbent material to adsorb CO2 in at least another one of the enclosures.

The methods may comprise reducing the temperature of the at least one enclosure after desorption of the adsorbed CChfrom the adsorbent material and before adsorption of CCh by the adsorbent material recommences. The methods may comprise adjusting the temperature control system and/or the pressure control system to maximize adsorption of CO2 from the air by the adsorbent material.

According to another aspect, the present invention is directed to a valve comprising: a body having at least one intake aperture allowing ingress of a fluid and at least one exhaust aperture allowing exhaust of a fluid, the at least one intake aperture in fluid communication with the at least one exhaust aperture; a piston movable within a central channel of the body between an open position and a closed position; a biasing element extending between the body and the piston within the central channel to bias the piston into the open position; and a vacuum flow path extending through the body and through the central channel.

Suitably, the valve comprises a plurality of intake apertures in an upper region of the body in fluid communication with a plurality of exhaust apertures in a base of the body.

Suitably, the vacuum flow path comprises a first channel extending from the base of the body into the central channel and a second channel extending from the from the central channel to a side wall of the body.

Preferably, a third channel extends between the second channel and the central channel.

Preferably, the body comprises a flange extending therefrom for attachment of the valve.

According to a further aspect, the present invention is directed to an enclosure to remove carbon dioxide (CO2) from the atmosphere by direct air capture (DAC), the enclosure comprising: a hollow chamber for accommodating an adsorbent material capable of adsorbing CO2, the hollow chamber sealable by a removable cover; an intake to communicate air into the hollow chamber of the enclosure; and an exhaust to communicate gasses out of the hollow chamber of the enclosure; wherein the intake and/or the exhaust comprise a valve comprising: a body having at least one intake aperture allowing ingress of a fluid and at least one exhaust aperture allowing exhaust of a fluid, the at least one intake aperture in fluid communication with the at least one exhaust aperture; a piston movable within a central channel of the body between an open position and a closed position; a biasing element within the central channel to bias the piston into the open position; and a vacuum flow path extending through the body and through the central channel.

Preferably, the adsorbent material is housed in a removable cartridge which is received and held within the hollow chamber of the enclosure.

Preferably, the hollow chamber of the enclosure comprises a heat exchanger to increase and decrease the temperature in the enclosure to assist in controlling adsorption and desorption of carbon dioxide by the adsorbent material.

Preferably, at least one wall of the hollow chamber, and in particular a base and a side wall of the hollow chamber comprise a one or more channels for fluid communication with the vacuum flow path in the one or more valves.

According to a further aspect, the present invention is directed to a cartridge to remove carbon dioxide (CO2) from the atmosphere by direct air capture (DAC), the cartridge comprising: a metallic honeycomb structure for holding an adsorbent material capable of adsorbing CO2; and a heat exchanger coupled to the metallic honeycomb structure.

Preferably, the heat exchanger is in the form of a metallic plate. Further features and/or aspects of the present invention will become apparent from the following detailed description.

BRIEF DESCRIPTION OF THE DRAWING

Embodiments of the present invention will now be described with reference to the accompanying drawings, which are provided by way of example only, wherein like reference numerals refer to like features. In the drawings:

FIG 1 illustrates a direct air capture (DAC) apparatus according to an embodiment of the present invention;

FIG 2 is an enlarged view of a lower portion of the DAC apparatus shown in FIG 1 showing an air flow path;

FIG 3 is a perspective view of one of the enclosures of the DAC apparatus shown in FIG 1 ;

FIG 4 is a cross sectional view of the enclosure shown in FIG 3;

FIG 5 is a plan view of one of the enclosures of the DAC apparatus shown in FIG 1 with a cover of the enclosure removed showing an adsorbent material inside the enclosure;

FIG 6 is a vacuum control circuit for an embodiment of the DAC apparatus according to the present invention comprising three enclosures;

FIG 6A is another vacuum control circuit for an embodiment of the DAC apparatus according to the present invention comprising three enclosures showing additional details relating to a controller and sensors;

FIG 7 is a vapour-compression control circuit for heat transfer in the embodiment of the DAC apparatus according to the present invention comprising three enclosures;

FIG 7A is another vapour-compression control circuit for heat transfer in the embodiment of the DAC apparatus according to the present invention comprising three enclosures showing additional details relating to a controller and sensors;

FIG 8 illustrates a system to remove carbon dioxide (CO2) from the atmosphere according to an embodiment of the present invention; FIG 9 is a perspective view of a valve of one of the enclosures shown in FIGS 3 to 5;

FIG 10 is a cross-sectional perspective view of the valve shown in FIG 9 wherein a piston of the valve has been removed;

FIG 11 is a cross-sectional view of the valve shown in FIG 9 with a piston in an open position;

FIG 12 is a cross-sectional view of the valve shown in FIG 9 with the piston in a closed position; and

FIG 13 is a perspective image of a section of a honeycomb structure to which an adsorbent material is applied and a heat exchanger plate;

FIG 14 is a perspective view of a square shaped enclosures of the DAC apparatus shown in FIG 1 ;

FIG 15 is a plan view of the square shaped enclosures shown in FIG 14.

Skilled addressees will appreciate that elements in the drawings are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the relative dimensions of some elements in the drawings may be distorted to help improve understanding of embodiments of the present invention. Embodiments of the present invention may be represented schematically and/or the drawings may omit one or more features for the sake of clarity.

DETAILED DESCRIPTION

With reference to FIGS 1 and 2, some aspects and embodiments of the present invention are directed to a direct air capture (DAC) apparatus 100 to remove carbon dioxide (CO2) from the atmosphere. The apparatus 100 comprises one or more enclosures 102 having an adsorbent material 104 inside the one or more enclosures capable of adsorbing CO2. The apparatus 100 comprises a temperature control system 106, shown in FIG 7, coupled to the one or more enclosures 102 to control the temperature in the one or more enclosures 102. The apparatus 100 comprises a pressure control system 108, shown in FIG 6, coupled to the one or more enclosures 102 to control the pressure in the one or more enclosures 102. At least some heat energy and/or at least some vacuum energy in the one or more enclosures 102 resulting from the process of desorption of the CC from the adsorbent material 104 is recycled for subsequent adsorption of CO2 by the adsorbent material 104 to significantly reduce the energy consumption of the DAC apparatus 100 compared with at least some of the prior art DAC apparatus.

As will be described in further detail herein with reference to FIGS 7 and 7A, to facilitate recycling of at least some heat energy in the one or more enclosures 102 the temperature control system 106 comprises at least a heat exchanger, a compressor and one or more valves coupled to the one or more enclosures 102. The transfer of heat is implemented using a vapourcompression heat transfer method.

As will be described in further detail herein with reference to FIGS 6 and 6A, to facilitate recycling of at least some vacuum energy in the one or more enclosures 102 the pressure control system 108 comprises at least a vacuum pump and one or more valves coupled to the one or more enclosures 102. The vacuum is transferred by opening the valves in the correct sequence to transfer the vacuum energy.

With particular reference to FIG 2, the apparatus 100 comprises an intake 110 to communicate air into the apparatus and an exhaust 112 to communicate gasses out of the apparatus 100. The enclosure 102 also comprises an intake 114 to communicate air into the enclosure 102 and an exhaust 116 to communicate gasses out of the enclosure 102.

With particular reference to FIGS 3 to 5, the enclosure 102 comprises a hollow chamber 118 which is sealed by a removable cover 120. The hollow chamber houses the adsorbent material 104 inside the enclosure 102. In preferred embodiments, the adsorbent material 104 is housed in a cartridge 122 which is received and held within the hollow chamber 118 of the enclosure 102 by any suitable means. Housing the adsorbent material 104 in a cartridge 122 enables the adsorbent material 104 in the enclosure 102 to be quickly and easily replaced, if and when necessary. The enclosure 102 comprises a heat exchanger 124 forming part of the temperature control system 106 to increase and decrease the temperature in the enclosure 102 to assist in controlling the adsorption and desorption of carbon dioxide by the adsorbent material 104. Further details of the enclosure 102 will be described herein with reference to FIGS 9 to 13.

The adsorbent material 104 can be any suitable material capable of adsorbing and releasing carbon dioxide by the temperature vacuum swing adsorption (TVSA) process. In preferred embodiments, the adsorbent material 104 is a metal organic framework (MOF), which is preferred due to the large surface area per unit volume due to the pore size and nanostructure of the MOF which has a high capacity for carbon dioxide adsorption. In other embodiments, adsorbent materials other than MOFs can be used.

In some embodiments, the apparatus 100 comprises a single enclosure 102. However, in preferred embodiments, the apparatus 100 comprises at least two enclosures 102 coupled together. In the embodiment shown in the accompanying FIGS 1 , 2, 6 and 7, the apparatus 100 comprises three enclosures 100 coupled together. In other embodiments, the apparatus 100 can comprise more than three enclosures 102 coupled together.

Further details of the pressure control system 108 will now be described with reference to FIGS 6 and 6A.

FIG 6 shows the pressure control system 108 for an embodiment of the DAC apparatus 100 comprising three enclosures 102 coupled together. The enclosures are in the form of canisters C1 , C2 and C3. However, the pressure control system 108 can be used with a DAC apparatus comprising a single enclosure 102, two enclosures or more than three enclosures102 and the pressure control system 108 can be modified accordingly.

For enclosure 102 in the form of canister C1 , an intake fan 126 (Fan F1 ) is coupled to the intake 114 of the enclosure 102 via a valve 128 (Valve V1 ). An exhaust fan 130 (Fan F2) is coupled to the exhaust 116 of the enclosure 102 via a valve 131 (Valve V2). Valves 128, 131 are each coupled to a control valve 132 (Control Valve V7) having a control input A. Control input A controls control valve 132 to apply or release a vacuum in the enclosure 102 in the form of canister C1 and to open and close the valves 128, 131 to the intake fan 126 and exhaust fan 130, respectively. Enclosure 102 in the form of canister C1 comprises heat exchanger 124. Enclosure 102 in the form of canister C2 has the same configuration as enclosure 102 in the form of canister C1 and comprises heat exchanger 124, an intake fan 126 (Fan F3), valve 128 (Valve V3), exhaust fan 130 (Fan F4), valve 131 (Valve V4) and control valve 132 (Control Valve V8) having a control input B.

Enclosure 102 in the form of canister C3 also has the same configuration as enclosure 102 in the form of canister C1 and comprises heat exchanger 124, an intake fan 126 (Fan F5), valve 128 (Valve V5), exhaust fan 130 (Fan F6), valve 131 (Valve V6) and control valve 132 (Control Valve V9) having a control input C.

Each control valve 132 is coupled to the atmosphere and to a vacuum pump 134 (P1 ). Vacuum pump 134 (P1 ) is coupled to a control valve 136 (Control Valve V10) having a control input D. Control valve 136 is coupled to the atmosphere and to a storage tank 138. Control input D switches the exhaust of the vacuum pump 134 between the storage tank 138 and the atmosphere.

Intake fans 126 (Fans F1 , F3, F5) draw the air into the respective enclosures 102 from the atmosphere. Preferably, the air is at ambient temperature and atmospheric pressure. Exhaust fans 130 (Fans F2, F4, F6) exhaust gasses from the respective enclosures 102 to the atmosphere.

FIG 6A shows additional details of the pressure control system 108 shown in FIG 6 relating to a controller and sensors of the pressure control system 108. Pressure control system 108 comprises a controller 160 in the form of a vacuum controller. Controller 160 provides control signals in the form of control inputs A to D to control valves 132 (Control Valves V7 to V10) and control input E to control vacuum pump 134 (P1 ) to control fluid flow through vacuum pump 134. Controller 160 provides control signals in the form of control outputs F1 , F3, F5 to intake fans 126 (Fans F1 , F3, F5) and control outputs F2, F4, F6 to exhaust fans 130 (Fans F2, F4, F6).

Pressure control system 108 comprises a sensor 162 (Sensor S1 ) coupled between intake fan 126 (Fan F1) and valve 128 (Valve V1 ) of enclosure 102 in the form of canister C1 . Sensor S1 comprises an air flow sensor 164 to detect the flow of air between intake fan 126 (Fan F1 ) and valve 128 (Valve V1 ) and provides an output signal indicative thereof in the form of signal Flow 1. Sensor S1 comprises a carbon dioxide (CO2) concentration sensor 166 to detect the concentration of CO2 in the air flowing between intake fan 126 (Fan F1 ) and valve 128 (Valve V1 ) and provides an output signal indicative thereof in the form of signal Gas1 .

Similarly, pressure control system 108 comprises a sensor 162 (Sensor

52) coupled between intake fan 126 (Fan F3) and valve 128 (Valve V3) of enclosure 102 in the form of canister C2. Sensor S2 comprises an air flow sensor 164 to detect the flow of air between intake fan 126 (Fan F3) and valve 128 (Valve V3) and provides an output signal indicative thereof in the form of signal Flow 2. Sensor S2 comprises a carbon dioxide (CO2) concentration sensor 166 to detect the concentration of CO2 in the air flowing between intake fan 126 (Fan F3) and valve 128 (Valve V3) and provides an output signal indicative thereof in the form of signal Gas2.

Similarly, pressure control system 108 comprises a sensor 162 (Sensor

53) coupled between intake fan 126 (Fan F5) and valve 128 (Valve V5) of enclosure 102 in the form of canister C3. Sensor S3 comprises an air flow sensor 164 to detect the flow of air between intake fan 126 (Fan F5) and valve 128 (Valve V5) and provides an output signal indicative thereof in the form of signal Flow 3. Sensor S3 comprises a carbon dioxide (CO2) concentration sensor 166 to detect the concentration of CO2 in the air flowing between intake fan 126 (Fan F5) and valve 128 (Valve V5) and provides an output signal indicative thereof in the form of signal Gas3.

Controller 160 receives the air flow signals Flowl , Flow2, Flow 3 and CO2 concentration signals Gas1 , Gas2, Gas3 as inputs to enable the controller 160 to provide the appropriate control signals A to E and F1 to F6 to control the adsorption and desorption processes in the enclosures 102 as described herein.

Further details of the temperature control system 106 will now be described with reference to FIGS 7 and 7A.

FIG 7 shows the temperature control system 106 for the embodiment of the DAC apparatus 100 comprising three enclosures 102 coupled together in the form of canisters C1 , C2 and C3 as described in relation to the pressure control system 108 shown in FIG 6. However, the temperature control system 106 can be used with a DAC apparatus comprising a single enclosure 102, two enclosures or more than three enclosures 102 and the temperature control system 106 can be modified accordingly.

Heat exchangers 124 shown in FIG 7 in the form of heat exchangers H1 , H2 and H3 are the heat exchangers 124 in the three enclosures 102 in the form of canisters C1 , C2 and C3 described in relation to the pressure control system 108 shown in FIG 6.

The temperature control system 106 comprises control valves 140 (Control Valves V1 , V2 and V3) coupled together. Control valves 140 (V1 , V2 and V3) are also coupled to heat exchangers 124 (H1 , H2 and H3) in a particular configuration to achieve the required heat transfer between the heat exchangers 124 in the three enclosures 102. In this embodiment, Control Valve V1 is coupled to heat exchangers H1 and H2, Control Valve V2 is coupled to heat exchangers H1 and H3 and Control Valve V3 is coupled to heat exchangers H2 and H3. Control valves 140 (V1 , V2 and V3) are also coupled to a heat exchanger 142 (H4) and a compressor 144 of a cooler 146 for gasses exiting the enclosures 102.

The temperature control system 106 comprises a plurality of thermal expansion (TX) valves 148 and check valves 150 coupled between the heat exchangers 124 (H1 , H2 and H3). In this embodiment, TX valve V4 and check valve V5 are coupled in series between heat exchangers H1 and H2, TX valve V6 and check valve V7 are coupled in series between heat exchangers H2 and H3 and TX valve V8 and check valve V9 are coupled in series between heat exchangers H1 and H3. Check valve V9 is in the opposition direction to check valves V5 and V7.

Control Valve V1 receives a control input X and when control input X=1 heat is transferred from heat exchanger H2 to heat exchanger H1 . Control Valve V2 receives a control input Y and when control input Y=1 heat is transferred from heat exchanger H1 to heat exchanger H3. The control input to Control Valve V3 depends on the control inputs to Control Valves V1 and V2. In this embodiment, when control input X=0 and control input Y=0 heat is transferred from heat exchanger H3 to heat exchanger H2.

FIG 7A shows additional details of the temperature control system 106 shown in FIG 7 relating to a controller and temperature sensors of the temperature control system 106. Temperature control system 106 comprises a controller 170 in the form of a heat controller. Controller 170 receives temperature sensor signals H1 , H2, H3 and H4 from temperature sensors 172 coupled to heat exchangers 124 (H 1 , H2 and H3) and heat exchanger 142 (H4) respectively. Controller 170 provides control signals in the form of control inputs X, Y to control valves 140 (Control Valves V1 , V2) and control input Z to control flow in compressor 144 (P1 ).

Hence, the apparatus 100 comprises one or more controllers coupled to the temperature control system 106 and the pressure control system 108, such as controllers 160, 170, to provide the control inputs described herein to coordinate control of the temperature and the pressure in the enclosures 102.

The temperature control system 106 and the pressure control system 108 of the DAC apparatus 100 are adjustable to cause the adsorbent material to adsorb CO2 from air drawn into the enclosure 102, reduce the pressure and increase the temperature in the enclosures 102 to cause the adsorbent material 104 to release the adsorbed CO2 and recycle one or more of heat energy and vacuum energy in the enclosures 102 for subsequent adsorption of CO2 by the adsorbent material from air drawn into the enclosure. In preferred embodiments, the temperature control system 106 and/or the pressure control system 108 are adjustable to maximize adsorption of CO2 from the air by the adsorbent material 104.

The DAC apparatus 100 removes carbon dioxide from the air in accordance with the known temperature vacuum swing adsorption (TVSA) process as summarised below with reference to the apparatus 100.

In the adsorption process, intake fan 126 blows ambient air through the enclosure 102 fitted with a cartridge 122 holding the carbon dioxide adsorbing material 104. Carbon dioxide is adsorbed by the adsorbent material 104. In the desorption process, after a time, air flow into the enclosure 102 is terminated and air is removed from the enclosure 102. Heat is then transferred to the adsorbent material 104 via the heat exchanger 124 in the enclosure 102, which in some embodiments, is attached to the cartridge 122. Carbon dioxide exits the adsorbent material 104 and is pumped to a storage tank 138 by vacuum pump 134 until there is little or no carbon dioxide left in the adsorbent material 104.

When the desorption process is complete, air is allowed to fill the enclosure 102 and heat is removed from the adsorbent material 104 using the heat exchanger 124 in the enclosure 102. Hence, air is drawn into the at least one enclosure 102 to reduce the temperature of the at least one enclosure 102 after desorption of the adsorbed CC from the adsorbent material and before adsorption of CO2 by the adsorbent material recommences in the same enclosure.

As soon as the temperature of the adsorption material 104 has reached the adsorption temperature and the air pressure in the enclosure 102 has reached the adsorption working pressure for the particular adsorption material being used, air is once again blown through the enclosure 102 by intake fan 126 to start the adsorption process again.

In accordance with embodiments of the present invention, where two or more enclosures 102 are coupled together, the adsorption and desorption processes in each enclosure 102 can be timed so that the energy used in the desorption process in one enclosure 102 can be moved to the next enclosure 102 rather than venting to atmosphere and being wasted. Hence, in some embodiments, the apparatus comprises at least two enclosures 102 coupled together and one or more of the heat energy and the vacuum energy is recycled between the at least two enclosures.

In accordance with some embodiments of the present invention, a single enclosure 102 can be used and energy moved to and from a heat exchanger exposed to the atmosphere. However, this would not be the most efficient use of the energy. In the embodiment comprising three enclosures 102 described herein, the duration of the adsorption process can be controlled to take, for example, 20 minutes, and the duration of the desorption process can be controlled to take 10 minutes and the energy can be transferred between the enclosures 102 in a round-robin arrangement.

In some embodiments, the apparatus 100 comprises three or more enclosures 102 coupled together, wherein one or more of the heat energy and the vacuum energy is recycled between the three or more enclosures 102. In such embodiments, desorption of the adsorbed CC from the adsorbent material 104 occurs in at least two of the enclosures 102 whilst the adsorbent material 104 adsorbs CO2 in at least another one of the enclosures 102.

With reference to the examples illustrated in FIGS 6, 6A, 7 and 7A, enclosure 102 in the form of canister C1 can be at the end of the adsorption process, enclosure 102 in the form of canister C2 can be halfway through its adsorption process and enclosure 102 in the form of canister C3 can be at the end of its desorption process. The energy can then be moved from canister C3 at the end the desorption process to canister C1 to begin its desorption process. The vacuum energy can be moved by transferring vacuum from canister C3 to canister C1 and transferring the heat from canister C3 to C1 . This sequence can repeat at the end of each process in a round-robin arrangement thus conserving as much energy as possible in the DAC process.

FIGS 7 and 7A shows a heat exchanger 142 for extracting energy from the carbon dioxide gas and water before it is pumped to the storage tank 138 shown in FIGS 6 and 6A, thus further conserving the energy requirements. The cooling process would also serve to condense water from the carbondioxide, thus drying the carbon dioxide before it is piped to the storage tank 138.

It will be appreciated that the apparatus 100 can further comprise a power source coupled to the temperature control system 106 and the pressure control system 108. The power source can include one or more sources of power and can be selected from at least the following: one or more renewable power sources, such as one or more solar panels, or wind power; one or more batteries; a utility power supply. According to another aspect, and with reference to FIG 8, embodiments of the present invention are directed to a system 800 to remove carbon dioxide (CO2) from the atmosphere comprising a plurality of the direct air capture (DAC) apparatus 100 coupled together. In such systems, multiple apparatus 100 can be coupled to a common storage tank 138 for storing CO2 removed from the atmosphere or each apparatus could have their own respective storage tank 138. It is envisaged that in some embodiments, the temperature control system 106 and the pressure control system 108 could be shared across multiple apparatus and the heat energy and vacuum energy moved between multiple apparatus 100 to minimise energy consumption.

According to a further aspect, the present invention is directed to a method of removing carbon dioxide (CO2) from the atmosphere with the direct air capture (DAC) apparatus 100. As described herein, the apparatus 100 comprises at least one enclosure 102 comprising the adsorbent material 104 capable of adsorbing CO2, an air intake 114 to communicate air into the enclosure 102 and an exhaust 116 to communicate gasses out of the enclosure 102. The apparatus 100 comprises the temperature control system 106 coupled to the at least one enclosure 102 to control a temperature within the at least one enclosure 102 and the pressure control system 108 coupled to the at least one enclosure 102 to control a pressure within the at least one enclosure 102. The method includes adjusting the temperature control system 106 and/or the pressure control system 108 to cause the adsorbent material 104 to adsorb CO2 from the air drawn into the enclosure 102, reduce the pressure and increase the temperature in the at least one enclosure 102 to cause the adsorbent material to release the adsorbed CO2 and recycle one or more of the heat energy and the vacuum energy in the one or more enclosures 102 to reduce the energy requirements for a subsequent process of adsorption of CO2 by the adsorbent material 104.

According to a yet further aspect, the present invention is directed to a method of removing carbon dioxide (CO2) from the atmosphere with the direct air capture (DAC) apparatus 100. The method comprises adjusting the temperature control system 106 and/or the pressure control system 108 to cause the adsorbent material 104 in the enclosure 102 to adsorb CO2 from air drawn into the enclosure. The method comprises reducing the pressure and increasing the temperature in the enclosure 102 to cause the adsorbent material 104 to release the adsorbed CO2. The method comprises recycling one or more of the heat energy and the vacuum energy in the enclosure 102 for a subsequent process of adsorption of CO2 by the adsorbent material.

As described herein, the methods can comprise recycling one or more of the heat energy and the vacuum energy between at least two enclosures 102 coupled together. In particular, as described herein, the methods can comprise recycling one or more of the heat energy and the vacuum energy between three or more enclosures 102 coupled together.

As described herein, the methods can comprise causing desorption of the adsorbed CC from the adsorbent material 104 to occur in at least two of the enclosures 102 whilst causing the adsorbent material 104 to adsorb CO2 in at least another one of the enclosures 102 in a round robin arrangement. For example, energy generated in one enclosure 102 from the adsorption process is moved to another enclosure 102 to apply heat to the adsorbent material 104 to commence the desorption process.

As described herein, the methods can comprise reducing the temperature of the at least one enclosure 102 via heat exchanger 124 after desorption of the adsorbed CC from the adsorbent material 104 and before adsorption of CCh by the adsorbent material 104 recommences.

The methods can comprise adjusting the temperature control system 106 and/or the pressure control system 108 to maximize adsorption of CO2 from the air by the adsorbent material 104. The particular temperature and pressure settings will depend on various factors, such as the type of adsorbent material 104 employed, the ambient air temperature and pressure, the flow rate of air drawn into the enclosures 102 by the intake fans 114.

Further details of the enclosure 102 will now be described with further reference to FIGS 9 to 13.

In accordance with another aspect of the present invention, and as shown in FIG 4, the enclosure 102 comprises the hollow chamber 118 for accommodating the adsorbent material 104 capable of adsorbing CO2. The hollow chamber 118 is sealable by the removable cover 120. The enclosure 102 comprises the intake 114 to communicate air into the hollow chamber 118 of the enclosure 102 and the exhaust 116 to communicate gasses out of the hollow chamber 118 of the enclosure 102. The intake 114 and/or the exhaust 116 comprise a valve 180. In preferred embodiments, both the intake 114 and/or the exhaust 116 comprise a valve 180. The valve 180 will be described in more detail with reference to FIGS 9 to 12.

The valve 180 comprises a body 182 having at least one intake aperture 184 allowing ingress of a fluid, in particular air, and at least one exhaust aperture 186 allowing exhaust of a fluid, in particular air. The at least one intake aperture 184 is in fluid communication with the at least one exhaust aperture 186.

In the embodiment of the valve 180 shown in the accompany drawings, the valve 180 comprises a plurality of intake apertures 184 in an upper region of the body 182 which are in fluid communication with a plurality of exhaust apertures 186 in a base 188 of the body 182.

The valve 180 comprises a piston 190 movable within a central channel 192 of the body between an open position, as shown in FIG 11 and a closed position, as shown in FIG 12.

The valve 180 comprises a biasing element 194 extending between the body 182 and the piston 190 within the central channel 192 to bias the piston 190 into the open position. The piston 190 comprises an internal channel 196 to accommodate at least part of the biasing element 194 in the open position shown in FIG 11 and to accommodate most of the biasing element 194 in the closed position shown in FIG 12. The biasing element 194 is located on and engages protrusion 198 on the base 188 of the body and protrusion 200 at the end of the internal channel 196. In the embodiment shown, the biasing element 194 is in the form of a helical spring but other biasing elements could be used.

The valve 180 comprises a vacuum flow path 202 extending through the body 182 and through the central channel 192. In the embodiment shown, the vacuum flow path 202 comprises a first channel 204 extending from the base 188 of the body 182 into the central channel 192 and a second channel 206 extending from the central channel 192 to a vacuum port 207 in side wall 208 of the body 182. In the embodiment shown, a third channel 210 extends between the second channel 206 and the central channel 192, in particular into a space or void 222 in the central channel 192 below the piston 190.

The piston 190 comprises an annular recess 193 which aligns with the vacuum flow path 202 forming a spool valve 195 when the valve 180 is in the closed position shown in FIG 12.

The body 182 of the valve 180 comprises a flange 212 extending therefrom for attachment of the valve 180 to the enclosure 102. In some embodiments the flange 212 extends around the circumference of the circular valve 212. As shown in FIG 4, one valve 180 is attached to the intake 114 of the enclosure 102 and one valve 180 is attached to the exhaust 116 of the enclosure 102.

In the embodiment shown in FIG 4, at least one wall of the hollow chamber 118 of the enclosure 102, and in particular a base 214 and a side wall 216 of the hollow chamber 118 comprise one or more channels 218, 220 for fluid communication with the vacuum flow path 202 in the valves 180.

In the open position or state shown in FIG 11 , the valve 180 allows air to flow along the air flow path between intake apertures 184 and the exhaust apertures 186. The second channel 206 leading to the vacuum port 207 is blocked by the spool valve 195 built into the piston 190 and no air can flow into the vacuum port 207. When a vacuum is applied to the vacuum port 207, a vacuum is presented in the space or void 222 below the piston 190 which applies a force to move the piston 190, and thus the valve 180 to the closed position shown in FIG 12. In the closed position the air flow path between intake apertures 184 and the exhaust apertures 186 is blocked, and the spool valve 195 built into the piston 190 opens the vacuum flow path 202. This allows air/gasses to flow in the vacuum path 202. When the vacuum is released at the vacuum port 207 the biasing element 194 returns the piston 190 and thus the valve 180 to the open position. In accordance with another aspect of the present invention, a cartridge 122 is provided to remove carbon dioxide (CO2) from the atmosphere by direct air capture (DAC). With reference to FIG 13, the cartridge 122 comprises a metallic honeycomb structure 224 for holding the adsorbent material 104 capable of adsorbing CO2. In preferred embodiments, the honeycomb structure 224 is made from aluminium, but it is envisaged that other metals can be used. The adsorbent material is applied to the honeycomb structure 224 by any suitable means known in the art. The honeycomb structure 224 provides a large surface area per unit volume and a long flow path for air passing through it in an effort to maximize the area of adsorbent material 104 available for adsorbing CO2.

The cartridge 122 comprises a heat exchanger 124 coupled to the metallic honeycomb structure 224. In preferred embodiments, the heat exchanger is in the form of a metallic plate.

FIG 13 shows a section of the honeycomb structure 224 in a basic rectangular form. The honeycomb structure 224 is shaped according to the shape of the hollow chamber 118 of the enclosure 102 in which the cartridge 122 is housed. The hollow chamber 118 of the enclosure 102 can be any shape, but in preferred embodiments the hollow chamber 118, and thus the cartridge 122, are symmetrical about a centre thereof. This is at least in part because the direction in which air is passed across the adsorbent material 104 on the honeycomb structure 224 is repeatedly reversed. The adsorbent material 104 tends to be depleted more towards the beginning of the flow path and the depletion of the adsorbent material 104 is thus evened out when the direction of flow is reversed. In some embodiments, the hollow chamber 118 of the enclosure 102 can house more than one cartridge 122. For example, the hollow chamber 118 can accommodate a plurality of concentric cartridges 122. This arrangement allows the cartridges to be selectively replaced according to the level of depletion of the adsorbent material 104. For example, if an outer cartridge 122 exhibits greater depletion of the adsorbent material 104, for example, because it is at the beginning of the flow path, the outer cartridge 122 can be replaced without the need to replace the inner cartridge.

Hence, the apparatus, methods, and systems according to embodiments of the present invention address, or at least ameliorate one or more of the aforementioned problems of the prior art and provide a useful commercial alternative. For example, recycling one or more of the heat energy and the vacuum energy in the enclosure 102, or between multiple enclosures 102 coupled together significantly reduces the energy consumption of the temperature vacuum swing adsorption (TVSA) process to remove carbon dioxide from the atmosphere in the direct air capture process. Energy generated in one enclosure 102 from the adsorption process is moved to another enclosure 102 to apply heat to the adsorbent material 104 to commence the desorption process. This recycling of energy avoids the need for further energy to be introduced to the enclosure 102 to commence the desorption process.

Heat calculations comparing known steam or resistive heating methods to the heat pump heating/cooling methods of the present invention indicate that there is an overall saving of 75% of the energy required to produce the same volume of CO2 when using the heat recovery and recycling techniques of the present invention. In addition to the energy recovery, it is expected that heat losses will be decreased, and the environments in the enclosures 102 controlled to more favourable temperatures with the likelihood that CO2 adsorption is improved.

Reversal of the air flow in accordance with embodiments of the present invention has the benefit of cleaning air filters in the system. The push/pull effect of the fans 126, 130 used for each enclosure 102 provide better control of the air flow in the system compared with at least some prior art DAC systems. Smaller fans can be used in the present invention, and they can be run at slower speeds than at least some prior art DAC systems, thus reducing energy consumption.

The valves 180 of the enclosures 102 have numerous advantages in that the valve 180 provides an active seal in the air flow path and does not require any energy source other than the vacuum to operate. Therefore, valve 180 does not require a continuous energy supply to keep it closed. The valve 180 only has two moving parts in the piston 190 and the biassing element 194. Therefore, the valve 180 is inherently reliable, requires less maintenance and provides an inherently safe design. The valve 180 is also compact, which creates a smaller protrusion from the body of the enclosure 102 allowing a higher density of enclosures 102, thus requiring less pipework between enclosures. The valve 180 is used for both the intake 114 and the exhaust 116, the functions of which are of course reversible when recycling energy between enclosures 102 as described herein.

Now referring to FIGS 14 and 15, the enclosure 226 is circular and comprises the hollow chamber 118 for accommodating the adsorbent material capable of adsorbing CO2 (not shown). The hollow chamber 118 is sealable by the removable cover (not shown). The enclosure 226 comprises the intake 114 to communicate air into the hollow chamber 118 of the enclosure 226 and the exhaust 116 to communicate gasses out of the hollow chamber 118 of the enclosure 226. The intake 114 and/or the exhaust 116 comprise a valve (not shown). In some embodiments, both the intake 114 and/or the exhaust 116 comprise a valve. The cartridge 122 is also square shaped to fit the square shaped enclosure 226 and comprises a heat exchanger 124 coupled to the metallic honeycomb structure 224. In some embodiments, the heat exchanger is in the form of a metallic plate.

Any of the features of the apparatus described herein can be combined in any combination with any one or more of the other features described herein within the scope of the invention.

In this specification, adjectives such as first and second, and the like may be used solely to distinguish one element or action from another element or action without necessarily requiring or implying any actual such relationship or order. Where the context permits, reference to an integer or a component or step (or the like) is not to be interpreted as being limited to only one of that integer, component, or step, but rather could be one or more of that integer, component, or step etc.

In this specification, the terms “comprises”, “comprising” or similar terms are intended to mean a non-exclusive inclusion, such that an apparatus that comprises a list of elements does not include those elements solely but may well include other elements not listed. Throughout the specification the aim has been to describe the invention without limiting the invention to any one embodiment or specific collection of features. Persons skilled in the relevant art may realize variations from the specific embodiments that will nonetheless fall within the scope of the invention.

Claims

1 . A direct air capture (DAC) apparatus to remove carbon dioxide (CO2) from the atmosphere, the apparatus comprising: at least one enclosure comprising: an adsorbent material inside the enclosure capable of adsorbing CO2; an intake to communicate air into the enclosure; and an exhaust to communicate gasses out of the enclosure; a temperature control system coupled to the at least one enclosure to control a temperature within the enclosure; and a pressure control system coupled to the at least one enclosure to control a pressure within the enclosure; wherein the temperature control system and/or the pressure control system are adjustable to: cause the adsorbent material to adsorb CO2 from air drawn into the enclosure; reduce the pressure and increase the temperature in the enclosure to cause the adsorbent material to release the adsorbed CO2; and recycle one or more of heat energy and vacuum energy in the enclosure for subsequent adsorption of CO2 by the adsorbent material from air drawn into the enclosure.

2. The apparatus of claim 1 , wherein the apparatus comprises at least two enclosures coupled together and one or more of the heat energy and the vacuum energy is recycled between the at least two enclosures.

3. The apparatus of claim 1 , wherein the apparatus comprises three or more enclosures coupled together, wherein one or more of the heat energy and the vacuum energy is recycled between the three or more enclosures.

4. The apparatus of claim 3, wherein desorption of the adsorbed CC from the adsorbent material occurs in at least two of the enclosures whilst the adsorbent material adsorbs CO2 in at least another one of the enclosures.

5. The apparatus of any preceding claim, wherein air is drawn into the at least one enclosure to reduce the temperature of the at least one enclosure after desorption of the adsorbed CChfrom the adsorbent material and before adsorption of CCh by the adsorbent material recommences in the same enclosure.

6. The apparatus of any preceding claim, wherein the temperature control system comprises at least a heat exchanger, a compressor and one or more valves coupled to the at least one enclosure.

7. The apparatus of any preceding claim, wherein the pressure control system comprises at least a vacuum pump and one or more valves coupled to the at least one enclosure.

8. The apparatus of any preceding claim, further comprising a controller coupled to the temperature control system and the pressure control system to coordinate control of the temperature and the pressure in the at least one enclosure.

9. The apparatus of any preceding claim, wherein the adsorbent material is housed in a cartridge within the enclosure.

10. The apparatus of any preceding claim, wherein the adsorbent material is a metal organic framework (MOF).

11 . The apparatus of any preceding claim, further comprising a power source coupled to the temperature control system and the pressure control system selected from the following: one or more solar panels; one or more batteries; a utility power supply; another renewable power source, such as wind power.

12. The apparatus of any preceding claim, wherein the air drawn into the enclosure is at ambient temperature and atmospheric pressure.

13. The apparatus of any preceding claim, wherein the temperature control system and/or the pressure control system are adjustable to maximize adsorption of CO2 from the air by the adsorbent material.

14. A system to remove carbon dioxide (CO2) from the atmosphere comprising a plurality of the direct air capture (DAC) apparatus as claimed in any preceding claim coupled together.

15. A method of removing carbon dioxide (CO2) from the atmosphere with a direct air capture (DAC) apparatus, the apparatus comprising: at least one enclosure comprising: an adsorbent material capable of adsorbing CO2; an intake to communicate air into the enclosure; and an exhaust to communicate gasses out of the enclosure; a temperature control system coupled to the at least one enclosure to control a temperature within the enclosure; and a pressure control system coupled to the at least one enclosure to control a pressure within the enclosure; and the method including adjusting the temperature control system and/or the pressure control system to: cause the adsorbent material to adsorb CO2 from the air drawn into the enclosure; reduce the pressure and increase the temperature in the enclosure to cause the adsorbent material to release the adsorbed CO2; and recycle one or more of heat energy and vacuum energy in the enclosure for subsequent adsorption of CO2 by the adsorbent material.

16. A method of removing carbon dioxide (CO2) from the atmosphere with a direct air capture (DAC) apparatus, the method comprising: adjusting a temperature control system and/or a pressure control system to cause an adsorbent material in an enclosure to adsorb CO2 from air drawn into the enclosure; reducing the pressure and increasing the temperature in the enclosure to cause the adsorbent material to release the adsorbed CO2; and recycling one or more of heat energy and vacuum energy in the enclosure for subsequent adsorption of CO2 by the adsorbent material.

17. The method of claim 15 or 16, comprising recycling one or more of the heat energy and the vacuum energy between at least two enclosures coupled together.

18. The method of claim 15, 6 or 17, comprising recycling one or more of the heat energy and the vacuum energy between three or more enclosures coupled together.

19. The method of claim 18, comprising causing desorption of the adsorbed CC from the adsorbent material to occur in at least two of the enclosures whilst causing the adsorbent material to adsorb CO2 in at least another one of the enclosures.

20. The method of any of claims 15 to 19, comprising reducing the temperature of the at least one enclosure after desorption of the adsorbed CC from the adsorbent material and before adsorption of CO2 by the adsorbent material recommences.

21 . The method of any of claims 15 to 20, comprising adjusting the temperature control system and/or the pressure control system to maximize adsorption of CO2 from the air by the adsorbent material.

22. A direct air capture (DAC) apparatus to remove carbon dioxide (CO2) from the atmosphere, the apparatus comprising: one or more enclosures having an adsorbent material inside the one or more enclosures capable of adsorbing CO2; a temperature control system and a pressure control system coupled to the one or more enclosures to control adsorption and desorption of CO2 by the adsorbent material; wherein at least some heat energy and/or at least some vacuum energy in the one or more enclosures resulting from desorption of the CC from the adsorbent material is recycled for subsequent adsorption of CO2 by the adsorbent material.

23. The apparatus of claim 22, wherein the temperature control system comprises at least a heat exchanger, a compressor and one or more valves coupled to the one or more enclosures.

24. The apparatus of claim 22 or 23, wherein the pressure control system comprises at least a vacuum pump and one or more valves coupled to the one or more enclosures.

25. A valve comprising: a body having at least one intake aperture allowing ingress of a fluid and at least one exhaust aperture allowing exhaust of a fluid, the at least one intake aperture in fluid communication with the at least one exhaust aperture; a piston movable within a central channel of the body between an open position and a closed position; a biasing element extending between the body and the piston within the central channel to bias the piston into the open position; and a vacuum flow path extending through the body and through the central channel.

26. The valve of claim 25 comprising a plurality of intake apertures in an upper region of the body in fluid communication with a plurality of exhaust apertures in a base of the body.

27. The valve of claim 26, wherein the vacuum flow path comprises a first channel extending from the base of the body into the central channel and a second channel extending from the central channel to a side wall of the body and preferably a third channel extending between the second channel and the central channel.

28. An enclosure to remove carbon dioxide (CO2) from the atmosphere by direct air capture (DAC), the enclosure comprising: a hollow chamber for accommodating an adsorbent material capable of adsorbing CO2, the hollow chamber sealable by a removable cover; an intake to communicate air into the hollow chamber of the enclosure; and an exhaust to communicate gasses out of the hollow chamber of the enclosure; wherein the intake and/or the exhaust comprise the valve of any of claims 25 to 27.

29. The enclosure of claim 28, wherein the adsorbent material is housed in a removable cartridge receivable within the hollow chamber.

30. The enclosure of claim 28 or 29, wherein the hollow chamber of the enclosure comprises a heat exchanger to increase and decrease the temperature in the enclosure to assist in controlling adsorption and desorption of carbon dioxide by the adsorbent material.

31 . The enclosure of any of claims 28 to 30, wherein at least one wall of the hollow chamber, and in particular a base and a side wall of the hollow chamber comprise one or more channels for fluid communication with the vacuum flow path in the one or more valves.

32. A cartridge to remove carbon dioxide (CO2) from the atmosphere by direct air capture (DAC), the cartridge comprising: a metallic honeycomb structure for holding an adsorbent material capable of adsorbing CO2; and a heat exchanger coupled to the metallic honeycomb structure.

33. The cartridge of claim 32, wherein the heat exchanger is in the form of a metallic plate.