Carbon dioxide recovery system

Abstract

This carbon dioxide recovery system comprises: an air blowing unit having a fan; an adsorption unit that is provided at a position in contact with an airflow generated by the air blowing unit and causes an adsorbent unit to adsorb carbon dioxide; a separation unit that separates the carbon dioxide from the adsorbent unit; and a rail. The adsorbent unit is conveyed along the rail, and the rail is branched.

Description

Carbon Dioxide Recovery System

[0001] The present invention relates to a carbon dioxide recovery system. This application claims priority based on Japanese Patent Application No. 2025-025524 filed in Japan on February 20, 2025, the content of which is incorporated herein by reference.

[0002] A DAC (Direct Air Capture) or DAC system, which is a system for recovering low-concentration carbon dioxide of about 410 ppm present in the atmosphere, is known.

[0003] Patent Document 1 discloses a carbon dioxide adsorption facility capable of removing carbon dioxide in the atmosphere by moving an adsorbent along a closed rail.

[0004] Japanese Patent Publication No. 2023-502736

[0005] Since the carbon dioxide present in the atmosphere has a low concentration in the DAC system, the carbon dioxide recovery efficiency is poor, and thus the carbon dioxide recovery cost is high, which is a technical problem. Therefore, further improvement of the carbon dioxide recovery efficiency is required.

[0006] One aspect of the present disclosure is a carbon dioxide recovery system including a blower unit having a fan, an adsorption unit provided at a position in contact with an air flow generated by the blower unit for adsorbing carbon dioxide to an adsorbent unit, a separation unit for separating the carbon dioxide from the adsorbent unit, and a rail, wherein the adsorbent unit is conveyed along the rail and the rail is branched.

[0007] According to the present disclosure, it is possible to provide a carbon dioxide recovery system with good carbon dioxide recovery efficiency.

[0008] This is a schematic top view of the carbon dioxide capture system according to Embodiment 1. This is a schematic front view of the carbon dioxide capture system according to Embodiment 1. This is a diagram illustrating the adsorbent unit of the carbon dioxide capture system according to Embodiment 1. This is a diagram illustrating the adsorbent unit of the carbon dioxide capture system according to Embodiment 1. This is a schematic top view of the carbon dioxide capture system according to the first modified example of Embodiment 1. This is a schematic top view of the carbon dioxide capture system according to the first modified example of Embodiment 1. This is a schematic top view of the carbon dioxide capture system according to the second modified example of Embodiment 1. This is a schematic top view of the carbon dioxide capture system according to the second modified example of Embodiment 1. This is a diagram illustrating the operating state of the blower and the position of the adsorbent unit in the carbon dioxide capture system according to the first modified example of Embodiment 1. This is a diagram illustrating the operating state of the blower and the position of the adsorbent unit in the carbon dioxide capture system according to the first modified example of Embodiment 1. This is a diagram illustrating the operating state of the blower and the position of the adsorbent unit in the carbon dioxide capture system according to the first modified example of Embodiment 1. This is a diagram illustrating that the blower operates in accordance with the carbon dioxide concentration in the space where the blower is installed, or the number of people, in the carbon dioxide capture system according to the third modified example of Embodiment 1. This figure illustrates how the air blower operates in accordance with the carbon dioxide concentration in the space where it is installed, or the number of people, in a carbon dioxide recovery system according to a third modification of Embodiment 1. This is an enlarged side view of the adsorbent unit. This is a cross-sectional view of the adsorbent unit in Figure 14.

[0009] <Embodiment 1> Hereinafter, a carbon dioxide capture system 90 according to Embodiment 1 of the present disclosure will be described with reference to the drawings.

[0010] Figure 1 is a schematic top view of the carbon dioxide capture system 90 according to Embodiment 1. Figure 2 is a schematic front view of the carbon dioxide capture system 90 according to Embodiment 1.

[0011] The carbon dioxide recovery system 90 comprises a blower unit 4 having a fan (not shown), an adsorbent unit 3 for adsorbing carbon dioxide, a separation unit 5 (5a, 5b) for separating carbon dioxide from the adsorbent unit 3, a rail 1, and an adsorption unit 2.

[0012] The air blower unit 4 is either the outdoor unit of an air conditioner (air conditioning unit) or a ventilation fan. In either case, the air blower unit 4 has a fan (not shown), and the fan rotates to generate airflow. In the case of the carbon dioxide recovery system 90 according to Embodiment 1, the air blower unit 4 is the outdoor unit of an air conditioner.

[0013] The adsorbent unit 3 only needs to contain an adsorbent inside and have permeability that allows the adsorbent to come into contact with air. The adsorbent contains a material capable of adsorbing carbon dioxide. Examples of materials capable of adsorbing carbon dioxide include amines, zeolites, silica gel, diatomaceous earth, alumina, and activated carbon. Multiple materials may be selected from the above, or materials other than those listed above may be used. The adsorbent may be granular (e.g., bead-shaped (spherical), pellet-shaped (cylindrical)). Alternatively, a powdered adsorbent may be used. In this case, the powdered adsorbent may be supported on the surface of a substrate. The substrate may be, for example, honeycomb-shaped. The adsorbent unit 3 is transported along the rail 1. In Figure 1, the direction in which the adsorbent unit 3 is transported is indicated by arrow D. The method of driving the adsorbent unit 3 is not particularly limited; for example, the adsorbent unit 3 may be motor-driven, where the adsorbent unit 3 is transported along the rail 1 by the motor's drive. Alternatively, the adsorbent unit 3 may be transported along the rail 1 by a linear motor drive. Alternatively, the adsorbent unit 3 may be transported along the rail 1 by air drive.

[0014] The adsorption section 2 is a container that can house and hold the adsorbent unit 3 inside. The adsorption section 2 is a component that adsorbs carbon dioxide contained in the airflow F generated by the fan of the blower section 4 onto the adsorbent as the airflow passes through it in contact with the adsorbent unit 3 housed inside the adsorption section 2. In other words, the adsorption section 2 is provided at a position (airflow path) that comes into contact with the airflow generated by the blower section 4 and is a component that adsorbs carbon dioxide onto the adsorbent unit 3. The shape of the adsorption section 2 is not limited as long as it can house the adsorbent unit 3 inside and has many slits or holes on its surface that allow the airflow to pass through while evenly contacting the adsorbent inside. For example, it can be cylindrical, a hollow rectangular parallelepiped, a hollow cube, or a hollow flat plate. In the example in Figure 1, the adsorption section 2 is provided adjacent to the blower section 4, but the adsorption section 2 is detachably attached to the blower section 4. In the adsorption section 2 shown in Figure 1, two adsorbent units 3 can be housed side by side. Therefore, carbon dioxide adsorption can be performed simultaneously on the two adsorbent units 3, shortening the cycle time and reducing running costs. Although a container is shown as an example for the adsorption section 2, it is not limited to this. For example, the vicinity of the air blower 4 (a position that can receive the airflow generated by the air blower) may be used as the adsorption section 2 without a container.

[0015] The separation unit 5 (5a, 5b) is a device that applies heat or pressure to the adsorbent unit 3 conveyed along the rail 1 to separate carbon dioxide from the adsorbent unit 3. For example, the separation unit 5 (5a, 5b) is equipped with a heating device (not shown) that supplies heat H into the separation unit 5 (5a, 5b). By heating the adsorbent unit 3, which has carbon dioxide adsorbed on it, with heat H, the carbon dioxide adsorbed on the adsorbent of the adsorbent unit 3 can be separated from the adsorbent of the adsorbent unit 3. Alternatively, the separation unit 5 (5a, 5b) may be connected to a vacuum pump 6 via piping 11, and carbon dioxide may be separated from the adsorbent of the adsorbent unit 3 by applying negative pressure to the separation unit 5 (5a, 5b). As a means of separating carbon dioxide from the adsorbent of the adsorbent unit 3, at least one of the following can be performed: applying heat H or applying negative pressure by the vacuum pump 6. Carbon dioxide may be separated from the adsorbent in the adsorbent unit 3 by applying both heat H and negative pressure using the vacuum pump 6. The heat H may be supplied not only by heating with a heating device, but also by supplying waste heat from an external source.

[0016] Rail 1 is the track along which the adsorbent unit 3 is transported. Rail 1 is usually formed by processing metal, but is not necessarily limited to metal; it may be formed by processing plastic, for example, when the weight of the adsorbent unit 3 is not heavy.

[0017] As shown in Figure 1, the rail 1 is partially branched. In the example in Figure 1, the branching of the rail 1 allows the adsorbent unit 3, which contains the adsorbent that has adsorbed carbon dioxide in the adsorption section 2, to be housed separately (in parallel) in the first separation section 5a and the second separation section 5b. This improves the carbon dioxide recovery efficiency. Furthermore, by housing the adsorbent unit 3 separately (in parallel) in the first separation section 5a and the second separation section 5b, the installation area of ​​the separation section 5 (5a, 5b) can be made more compact, thus making the overall installation area of ​​the carbon dioxide recovery system 90 more compact. Moreover, by housing the adsorbent unit 3 separately (in parallel) in the first separation section 5a and the second separation section 5b, carbon dioxide can be separated in parallel, shortening the cycle time and reducing running costs. In Figure 1, one adsorption section 2 and two separation sections 5 are shown, but the number is not limited and can be changed as appropriate depending on the characteristics of the adsorbent.

[0018] Furthermore, the control unit 40 may be electrically connected to the rail 1. The control signal transmitted from the control unit 40 to the rail 1 may control the movement speed of the adsorbent unit 3 and whether the adsorbent unit 3 is transported to the first separation section 5a side or the second separation section 5b side of the branched rail 1, by switching rail 1, etc. Note that the control unit 40 does not necessarily need to be electrically connected to the rail 1, and the control signal may be transmitted wirelessly from the control unit 40 to the adsorbent unit 3 or the branching point of the rail 1.

[0019] As shown in Figure 2, the air blower 4 is installed on the ground 12. The ground 12 is not limited to a soil surface, but may be a concrete surface, a building floor, or the floor of a balcony exposed to the outdoors. In the example in Figure 2, a support part 10a may be provided to connect the lower surface of the rail 1 and the air blower 4, supporting the rail 1 from below.

[0020] As shown in Figure 1, the rail 1 is arranged in a roughly rectangular shape in plan view, with the longer side of the rectangle being the X direction, the shorter side being the Y direction, and the direction away from the ground 12 in Figure 2 being the Z direction. For convenience, in Figure 1, the direction from the air blower 4 towards the separation unit 5 is the +X direction, the flow direction of the airflow F indicated by arrow F is the -Y direction, and in Figure 2, the direction away from the ground 12 is the +Z direction. The distance in the +Z direction is sometimes referred to as the height from the ground 12. As shown in Figure 1, in the air blower 4, the airflow F generated by the fan passes through the adsorbent unit 3 housed in the adsorption unit 2 in the -Y direction, and then the airflow is discharged in the +Z direction in Figure 2.

[0021] Next, the adsorbent unit 3 will be described in more detail with reference to Figures 3 and 4. Figures 3 and 4 correspond to Figure 1, which is a schematic top view of the carbon dioxide recovery system 90 according to Embodiment 1, but the air blower unit 4 is omitted. Figures 3 and 4 are diagrams illustrating the adsorbent unit 3 of the carbon dioxide recovery system 90 according to Embodiment 1, respectively.

[0022] Multiple adsorbent units 3 are provided on the rail 1, but only one may be provided on the rail 1. When multiple adsorbent units 3 are provided, and three adsorbent units 3 are lined up along the long side of the rectangular rail 1, adjacent adsorbent units 3 may be lined up at equal intervals A in the length direction of the rail 1, as shown in Figure 3. On the other hand, when multiple adsorbent units 3 are provided, and three adsorbent units 3 are lined up along the long side of the rectangular rail 1, adjacent adsorbent units 3 may be lined up at intervals A and intervals B shorter than interval A in the length direction of the rail 1, as shown in Figure 4. In this way, the interval (distance) between adsorbent units 3 in the length direction of the rail 1 is adjustable. By being able to adjust the interval between adsorbent units 3, the effect of reducing transport time loss when moving the adsorbent units 3 is obtained, and the effect of increasing design freedom is obtained by eliminating the constraint of determining the position of the adsorbent units 3 according to the distance between the adsorption part 2 and the separation part 5 (5a, 5b).

[0023] Typically, DAC systems require air transport equipment and air transport energy to collect air from the atmosphere and recover carbon dioxide using an adsorbent. If the adsorbent is fixed in a position where it is hit by the airflow of equipment with a blowing device such as an air conditioner, the running cost of the air conditioner increases due to the increased airflow resistance caused by the fixed adsorbent. In the case of air conditioners, the increased airflow resistance caused by the fixed adsorbent reduces the airflow of the air conditioner. Therefore, the performance of the air conditioner deteriorates. Patent Document 1 requires a large installation space because the rails are arranged in a circle. Also, a circular layout of rails requires multiple blowers, which in turn requires a lot of blowing power. Therefore, there are challenges such as low layout flexibility and high initial costs due to the high cost of curved rails.

[0024] Compared to Patent Document 1, the carbon dioxide capture system 90 according to Embodiment 1 has the advantages of not requiring a large installation space, not requiring multiple air blowers, and not requiring a lot of air blowing power, thus offering greater layout flexibility and reducing initial costs.

[0025] <First Modification of Embodiment 1> Next, a carbon dioxide capture system 91 according to the first modification of Embodiment 1 will be described with reference to Figures 5 and 6. Note that the same configuration as in Embodiment 1 will not be described, and only the differences from Embodiment 1 will be explained.

[0026] Figures 5 and 6 are schematic top views of a carbon dioxide capture system 91 according to a first modification of Embodiment 1. The carbon dioxide capture system 91 according to the first modification of Embodiment 1 differs from the carbon dioxide capture system 90 according to Embodiment 1 in that it has multiple rails 1. Specifically, the carbon dioxide capture system 91 according to the first modification of Embodiment 1 has a total of two rails: a first rail 1a and a second rail 1b. In a plan view, the first rail 1a and the second rail 1b are arranged parallel to each other, and the second rail 1b is provided adjacent to the first rail 1a in the -Y direction. The heights of the first rail 1a and the second rail 1b from the ground 12 may be the same or different.

[0027] Adsorbent units 3 are provided on the first rail 1a and the second rail 1b in a transportable manner. That is, the adsorbent units 3 provided on the first rail 1a are provided in a transportable manner relative to the first rail 1a, and the adsorbent units 3 provided on the second rail 1b are provided in a transportable manner relative to the second rail 1b.

[0028] Therefore, in the state shown in Figure 5, the adsorbent unit 3 provided on the second rail 1b adsorbs carbon dioxide onto the adsorbent in the adsorption section 2, while the adsorbent unit 3 provided on the first rail 1a separates the carbon dioxide that was adsorbed onto the adsorbent of the adsorbent unit 3 from the adsorbent of the adsorbent unit 3 in the separation section 5.

[0029] On the other hand, in the state shown in Figure 6, the adsorbent unit 3 is transported from the state shown in Figure 5 to the first rail 1a and the second rail 1b respectively. The adsorbent unit 3 on the first rail 1a adsorbs carbon dioxide onto the adsorbent in the adsorption section 2, while the adsorbent unit 3 on the second rail 1b separates the carbon dioxide that was adsorbed onto the adsorbent of the adsorbent unit 3 from the adsorbent of the adsorbent unit 3 in the separation section 5.

[0030] In the carbon dioxide recovery system 91 according to the first modified example of Embodiment 1, the state shown in Figure 5 and the state shown in Figure 6 can be repeated. This establishes a carbon dioxide adsorption / desorption cycle. Specifically, the adsorbent unit 3 is transported along the rail 1 and can adsorb and desorb carbon dioxide by reciprocating between the blowing unit 4 and the separation unit 5 (5a, 5b). Furthermore, because the adsorbent unit 3 reciprocates, the rail 1 can be set to a shorter length, simplifying the transport mechanism for the adsorbent unit 3, thus saving on the cost of laying the rail 1 and keeping the initial cost low. In addition, the carbon dioxide recovery system 91 can be made more compact, and the transport mechanism for the adsorbent unit 3 can be simplified, improving the reliability of the device. Although Figures 5 and 6 show an example with two rails, the first rail 1a and the second rail 1b, there may be one rail 1 or three or more rails.

[0031] Furthermore, as shown in Figures 5 and 6, a branch rail 10b may be provided between the first rail 1a and the second rail 1b. The provision of the branch rail 10b allows the adsorbent unit 3 to be transported between the first rail 1a and the second rail 1b. That is, although the examples in Figures 5 and 6 show the case in which the adsorbent units 3 provided on the first rail 1a and the second rail 1b respectively reciprocate on the first rail 1a and the second rail 1b, the system is not limited to this. Carbon dioxide adsorbed on the adsorbent by the adsorption unit 2 on the first rail 1a may be transported via the branch rail 10b and separated from the adsorbent by the separation unit 5 on the second rail 1b. Similarly, carbon dioxide adsorbed on the adsorbent by the adsorption unit 2 on the second rail 1b may be transported via the branch rail 10b and separated from the adsorbent by the separation unit 5 on the first rail 1a. This improves the carbon dioxide recovery efficiency. Alternatively, the movement speed of the adsorbent unit 3 on the first rail 1a and the second rail 1b, and the direction in which the adsorbent unit 3 moves along the branch rail 10b, may be controlled by transmitting control signals from the control unit 40 to the adsorbent unit 3 or the branch rail 10b via wired or wireless means. The control unit 40 may control only the movement speed of the adsorbent unit 3, or only the direction in which the adsorbent unit 3 moves, or it may control both the movement speed and the direction in which the adsorbent unit 3 moves.

[0032] <Second modified example of Embodiment 1>

[0033] Next, a carbon dioxide capture system 92 according to a second modification of Embodiment 1 will be described with reference to Figures 7 and 8. Note that the same configuration as the first modification of Embodiment 1 will not be described, and only the differences from the first modification of Embodiment 1 will be explained.

[0034] Figures 7 and 8 are schematic top views of a carbon dioxide recovery system 92 according to a second modification of Embodiment 1. The carbon dioxide recovery system 92 according to the second modification of Embodiment 1 differs from the carbon dioxide recovery system 91 according to the first modification of Embodiment 1 in that it has two blowing units 4 and two adsorption units 2, the first rail 1a and second rail 1b branch off to provide a third rail 1c and a fourth rail 1d, a separation unit 5a is provided between the first rail 1a and the second rail 1b, a separation unit 5b is provided between the third rail 1c and the fourth rail 1d, and valves 8 are provided in the piping 11 that connects the separation unit 5a and the separation unit 5b to the vacuum pump 6, respectively. For convenience, in the following description, the adsorbent unit 3 is described separately as adsorbent unit 3a, adsorbent unit 3b, and adsorbent unit 3c.

[0035] As shown in Figure 7, the carbon dioxide recovery system 92 according to the second modification of Embodiment 1 is provided with two air blowers 4 and two adsorption units 2. That is, two air blowers 4 are provided adjacent to each other on the first rail 1a and the second rail 1b, which are arranged parallel to each other in a plan view, and an adsorption unit 2 is attached to each of the two air blowers 4. The two air blowers 4 and the two adsorption units 2 are adjacent to each other in the X direction. Therefore, the adsorption units 2 containing the adsorbent unit 3a can be attached to the two air blowers 4, which are provided adjacent to each other in the X direction along the first rail 1a and the second rail 1b.

[0036] Similar to the carbon dioxide capture system 90 shown in Figure 1 and the carbon dioxide capture system 91 shown in Figure 5, the carbon dioxide capture system 92 shown in Figure 7 is also provided with a branching rail 1e, so that the first rail 1a branches into the first rail 1a and the third rail 1c, and the second rail 1b branches into the second rail 1b and the fourth rail 1d.

[0037] In the state shown in Figure 7, adsorbent units 3b are provided on the first rail 1a and the second rail 1b, which are located in the separation section 5a, and adsorbent units 3c are provided on the third rail 1c and the fourth rail 1d, which are located in the separation section 5b. Adsorbent units 3a are provided on two adsorption sections 2 that are located adjacent to each other in the X direction on the second rail 1b.

[0038] By transitioning from the state shown in Figure 7 to the state shown in Figure 8, a carbon dioxide adsorption and desorption cycle can be established. Specifically, from the state shown in Figure 7, adsorbent units 3b are transported to two adsorption units 2 located adjacent to each other in the X direction on the first rail 1a, and adsorbent units 3a are also transported to the first rail 1a and the second rail 1b located on the separation unit 5a.

[0039] In this case, as shown in Figure 7, of the adsorbent units 3b provided on the first rail 1a and the second rail 1b of the separation section 5a, the adsorbent unit 3b provided on the first rail 1a is transported onto the first rail 1a, thereby housing it in the adsorbent unit 2 located on the -X side of the two adsorbent units 2 located adjacent to each other in the X direction on the first rail 1a (arrow D3b in Figure 8, which extends straight along the first rail 1a). Also, as shown in Figure 7, of the adsorbent units 3b provided on the first rail 1a and the second rail 1b of the separation section 5a, the adsorbent unit 3b provided on the second rail 1b is transported onto the first rail 1a via the branch rail 1e, thereby housing it in the adsorbent unit 2 located on the +X side of the two adsorbent units 2 located adjacent to each other in the X direction on the first rail 1a (arrow D3b in Figure 8, which passes through the branch rail 1e).

[0040] After the adsorbent unit 3b is transported to two adsorption sections 2 located adjacent to each other in the X direction on the first rail 1a, in the state shown in Figure 7, the adsorbent unit 3a located on the +X direction side of the two adsorption sections 2 located adjacent to each other in the X direction on the second rail 1b is transported along the second rail 1b to the separation section 5a (arrow D3a in Figure 8, which extends straight along the second rail 1b). Next, in the state shown in Figure 7, the adsorbent unit 3a located on the -X direction side of the two adsorption sections 2 located adjacent to each other in the X direction on the second rail 1b is transported via the branch rail 1e to the separation section 5a on the first rail 1a (arrow D3a in Figure 8, which passes through the branch rail 1e).

[0041] In this way, by transitioning from the state shown in Figure 7 to the state shown in Figure 8, a carbon dioxide adsorption and desorption cycle can be established. In this carbon dioxide recovery system 92 according to the second modification of the first embodiment, since there are two air blowers 4, it can be applied to larger outdoor units of air conditioners. In addition, since a total of six adsorbent units 3 (3a, 3b, 3c) are transported to adsorb carbon dioxide, a larger amount of carbon dioxide can be adsorbed.

[0042] Furthermore, by providing the branch rail 1e, the adsorbent units 3 can be housed separately (in parallel) in the first separation section 5a and the second separation section 5b. By housing the adsorbent units 3 separately (in parallel) in the first separation section 5a and the second separation section 5b in this way, the installation area of ​​the separation section 5 (5a, 5b) can be made compact, and thus the overall installation area of ​​the carbon dioxide recovery system 92 can also be made compact. In addition, by housing the adsorbent units 3 separately (in parallel) in the first separation section 5a and the second separation section 5b, carbon dioxide can be separated in parallel, which shortens the cycle time and reduces running costs. Alternatively, the movement speed of the adsorbent units 3 on the first rail 1a and the second rail 1b, and the direction in which the adsorbent units 3 move along the branch rail 1e can be controlled by transmitting control signals from the control unit 40 to the adsorbent units 3a, 3b, 3c, or branch rail 1e via wired or wireless means.

[0043] In the carbon dioxide recovery system 92 according to the second modification of Embodiment 1, valves 8 are provided in the piping 11 connecting the separation unit 5a and separation unit 5b to the vacuum pump 6, respectively, so that negative pressure can be selectively applied to the separation unit 5a and separation unit 5b. That is, carbon dioxide can be selectively separated from any of the adsorbent units 3a, 3b, or 3c housed in the separation unit 5a and separation unit 5b. The opening and closing of the valves 8 may also be controlled by transmitting control signals from the control unit 40 to the valves 8 via wired or wireless means.

[0044] <Operating state of the blower unit and position of the adsorbent unit> Next, the relationship between the operating state of the blower unit 4 and the position of the adsorbent unit 3 will be described with reference to FIGS. 9, 10, and 11. This relationship applies commonly to the carbon dioxide recovery system 90 according to Embodiment 1, the carbon dioxide recovery system 91 according to the first modification of Embodiment 1, and the carbon dioxide recovery system 92 according to the second modification of Embodiment 1. In the following description, the carbon dioxide recovery system 91 according to the first modification of Embodiment 1 will be described as an example. FIGS. 9, 10, and 11 are all diagrams for explaining the operating state of the blower unit 4 and the position of the adsorbent unit 3 in the carbon dioxide recovery system 91 according to the first modification of Embodiment 1.

[0045] When the operating state of the blower unit 4 shown in FIG. 9 is rated operation, the adsorbent unit 3 is separated from the vicinity of the blower unit 4. That is, when the blower unit 4 is operating at rated operation, there is no adsorbent unit 3 in the vicinity of the blower unit 4. This is because when the blower unit 4 is operating at rated operation, the fan in the blower unit 4 is rotating at a high speed, so the flow velocity of the air flow F is large. Therefore, by not positioning the adsorbent unit 3 near the adsorption unit 2, that is, by not housing the adsorbent unit 3 in the adsorption unit 2, the adsorbent can be prevented from being exposed to the air flow F with a large flow velocity, and the occurrence of a large pressure loss can be suppressed.

[0046] When the operating state of the blower unit 4 shown in FIG. 10 is intermediate operation, the adsorbent unit 3 is arranged near the blower unit 4. That is, when the blower unit 4 is operating in intermediate operation, there is an adsorbent unit 3 near the blower unit 4. This is because when the blower unit 4 is operating in intermediate operation, the fan in the blower unit 4 is rotating at a low speed, so the flow velocity of the air flow F is small. Therefore, even if the adsorbent is exposed to the air flow F with a small flow velocity, the pressure loss can be kept low. Therefore, when the fan 25 of the air conditioner 100 is rotating at a low speed, even if the adsorbent unit 3 is housed in the adsorption unit 2, carbon dioxide can be absorbed while suppressing an increase in pressure loss. When the operating state of the blower unit 4 is intermediate operation, as shown in FIG. 11, a plurality of adsorbent units 3 may be arranged in the flow direction of the air flow F.

[0047] When the operating state of the blower unit 4 shown in FIG. 11 is stopped, only the fan of the blower unit 4 is operated, and the adsorbent unit 3 is arranged near the blower unit 4. That is, when the blower unit 4 is stopped, only the fan of the blower unit 4 is operated, and one or more adsorbent units 3 are installed near the blower unit 4. This is because when the blower unit 4 is stopped, by driving only the fan of the blower unit 4, the amount of carbon dioxide recovered from the outdoor unit of the air conditioner can be increased as a carbon dioxide recovery device during the period when the air conditioner is not in use. Therefore, during the intermediate period when the air conditioner is not operating, such as in warm spring or autumn, the air conditioner can be effectively used as a carbon dioxide recovery device. When the operating state of the blower unit 4 is stopped, as shown in FIG. 11, a plurality of adsorbent units 3 may be arranged in the air flow direction F.

[0048] As described above, the adsorbent unit 3 operates in accordance with the operating state of the blower unit 4. By applying the relationship between the operating state of the blower unit 4 and the position of the adsorbent unit 3 as described above, in the carbon dioxide recovery system 90 according to Embodiment 1, the carbon dioxide recovery system 91 according to the first modification of Embodiment 1, and the carbon dioxide recovery system 92 according to the second modification of Embodiment 1, the carbon dioxide recovery efficiency can be improved without reducing the air conditioning efficiency of the air conditioner. Therefore, the running costs of the carbon dioxide recovery systems 90, 91, and 92 can be reduced. Although the branch rail 10b is not shown in the carbon dioxide recovery system 91 shown in FIGS. 9, 10, and 11, the branch rail 10b may be provided in the same manner as the carbon dioxide recovery system 91 shown in FIGS. 5 and 6. Further, a signal indicating the operating state of the blower unit 4 is input to the control unit 40, and the control unit 40 sends a control signal to the adsorbent unit 3 by wire or wirelessly, so that the position of the adsorbent unit 3 may be controlled in accordance with the operating state of the blower unit 4.

[0049] <Third Modification of Embodiment 1> Next, the carbon dioxide recovery system 93 according to the third modification of Embodiment 1 will be described with reference to FIGS. 12 and 13. Regarding the configuration similar to that of the first modification of Embodiment 1, the description thereof will be omitted, and only the differences from the first modification of Embodiment 1 will be described.

[0050] Figures 12 and 13 both illustrate how the air blower 4 operates in accordance with the carbon dioxide concentration in the space where it is installed, or the number of people, in the carbon dioxide recovery system 93 according to the third modification of Embodiment 1. The carbon dioxide recovery system 93 according to the third modification of Embodiment 1 differs from the carbon dioxide recovery system 91 according to the first modification of Embodiment 1 in that the air blower 4 is a ventilation fan, there is no branch rail 10b, and it is equipped with a carbon dioxide concentration sensor 50. Note that the carbon dioxide recovery system 93 according to the third modification of Embodiment 1 shown in Figures 12 and 13 may also be equipped with a branch rail 10b, similar to the carbon dioxide recovery system 91 according to the first modification of Embodiment 1 shown in Figures 5 and 6.

[0051] As shown in Figure 12, if the carbon dioxide concentration in the space where the air blower 4 is installed is low, or if there are few people in the space where the air blower 4 is installed, the adsorbent unit 3 should be moved away from the vicinity of the air blower 4. This is because, when the carbon dioxide concentration in the space where the air blower 4 is installed is low, or when there are few people in the space where the air blower 4 is installed, the fan inside the air blower 4 rotates at a low speed. In such cases, if the adsorbent unit 3 is placed in the adsorption unit 2, the power consumption of the air blower 4 will increase due to the airflow resistance of the adsorbent unit 3, even though the amount of carbon dioxide recovered is small.

[0052] As shown in Figure 13, if the carbon dioxide concentration in the space where the air blower 4 is installed is high, or if there are many people in the space where the air blower 4 is installed, one or more adsorbent units 3 are installed near the air blower 4. This is because, when the carbon dioxide concentration in the space where the air blower 4 is installed is high, or when there are many people in the space where the air blower 4 is installed, the fan inside the air blower 4 rotates at high speed, so by housing the adsorbent unit 3 in the adsorption unit 2, the amount of carbon dioxide recovered can be increased, and the carbon dioxide recovery efficiency can be improved.

[0053] In this case, when the carbon dioxide concentration in the space where the air blower 4 is installed is low or high, a threshold can be set, and the decision can be made based on whether the carbon dioxide concentration is higher or lower than the threshold. For example, 1000 ppm can be set as the threshold. Also, whether the number of people in the space where the air blower 4 is installed is high or low can be determined, for example, by whether it is more or less than 50% of the legally defined occupancy capacity per floor area of ​​that space.

[0054] The carbon dioxide concentration may be measured by installing a carbon dioxide concentration sensor 50 in the space where the air blower 4 is installed. The number of people may be calculated by installing an imaging device 30 such as a camera in the space where the air blower 4 is installed and analyzing the captured data using known means. Information regarding the carbon dioxide concentration and the number of people in the space where the air blower 4 is installed is transmitted to the control unit 40, and the control unit 40, upon receiving this information, may control the position of the adsorbent unit 3 by transmitting a control signal to the adsorbent unit 3 via wired or wireless means. The carbon dioxide concentration sensor 50 may be installed in the air blower 4, or it may be installed somewhere else in the space where the air blower 4 is installed.

[0055] As described above, the adsorbent unit 3 operates in accordance with the carbon dioxide concentration or the number of people in the space where the air blower 4 is installed. Therefore, the carbon dioxide recovery efficiency can be improved in accordance with the carbon dioxide concentration or the number of people in the space where the air blower 4 is installed, thereby reducing the running costs of the carbon dioxide recovery system 93.

[0056] <Structure of the Adsorbent Unit> Next, the structure of the adsorbent unit 3 will be explained with reference to Figures 14 and 15. Figure 14 is an enlarged side view of the adsorbent unit 3. Figure 15 is a cross-sectional view of the adsorbent unit 3 of Figure 14 as seen from the VV section.

[0057] As shown in Figures 14 and 15, the adsorbent unit 3 is suspended and supported from the rail 1. That is, the adsorbent unit 3 is provided so as to be movable relative to the rail 1 while suspended downward from the rail 1. The adsorbent unit 3 is suspended downward from the rail 1 via the suspension portion 9 so as to be movable relative to the rail 1. The connection configuration between the suspension portion 9 and the rail 1 is not particularly limited, as long as the adsorbent unit 3 is suspended from the rail 1 via the suspension portion 9 so as to be movable relative to the rail 1.

[0058] Thus, when the adsorbent unit 3 is suspended downward from the rail 1 and moves along the rail 1, the weight of the adsorbent unit 3 suppresses tilting of the adsorbent unit 3 in the +Y and -Y directions around the rail 1, as seen in the cross-section of Figure 15. Therefore, the adsorbent unit 3 can be moved along the rail 1 in a stable state, and the adsorbent unit 3 can be smoothly inserted into and removed from the adsorption section 2 or the separation section 5 (5a, 5b).

[0059] Furthermore, the rails 1 may be arranged in parallel in the Z direction, and the adsorbent unit 3 may be supported by the rails 1 in both the +Z and -Z directions.

[0060] Furthermore, part or all of the control unit 40 may be implemented using a microcomputer equipped with a processor and memory. The microcomputer may be configured as an Electronic Control Unit (ECU). The processor may include a Central Processing Unit (CPU). The memory may include both volatile and non-volatile memory. The control unit 40 may be configured with dedicated hardware or it may be part of a computer system. The computer system may perform the processing related to the control unit 40 by reading a program stored on a computer-readable storage medium and executing the read program. "Reading a program recorded on a recording medium and executing it" includes installing the program on the computer system. "Computer system" includes a processor and main memory, as well as software such as an OS (Operating System) and hardware such as peripheral devices. "Computer system" is not limited to a single computer device, but may include multiple computer devices connected using a network including the Internet, WAN (Wide Area Network), LAN (Local Area Network), dedicated lines, and other communication lines. "Computer-readable recording media" refers to portable media such as flexible disks, magneto-optical disks, ROMs (Read Only Memory), CD-ROMs, and storage devices such as hard disks built into computer systems. Thus, the recording media on which the program is stored may also be non-transient recording media such as CD-ROMs.

[0061] Here, the number of adsorbent units 3 is not limited to the number shown in the diagram, and can be freely increased or decreased in accordance with the airflow rate of the air blower unit 4. Therefore, the carbon dioxide recovery efficiency can be improved.

[0062] Other embodiments or modifications described above may be combined as appropriate.

[0063] 1, 1a, 1b, 1c, 1d Rails 1e, 10b Branching rails 2 Adsorption unit 3 Adsorbent unit 4 Air blower 5, 5a, 5b Separation unit 6 Vacuum pump 8 Valve 9 Suspension unit 10a Support unit 11 Piping 30 Imaging device 40 Control unit 50 Carbon dioxide concentration sensor 90, 91, 92, 93 Carbon dioxide recovery system

Claims

1. A carbon dioxide recovery system comprising: a blowing unit having a fan; an adsorption unit provided at a position in contact with the airflow generated by the blowing unit and adsorbing carbon dioxide onto an adsorbent unit; a separation unit for separating the carbon dioxide from the adsorbent unit; and rails, wherein the adsorbent unit is transported along the rails and the rails are branched.

2. The carbon dioxide recovery system according to claim 1, wherein the adsorbent unit is capable of adsorbing and desorbing carbon dioxide by reciprocating between the air blowing unit and the separation unit.

3. The carbon dioxide recovery system according to claim 1 or 2, wherein the adsorbent unit operates in accordance with the operating state of the blower.

4. The carbon dioxide recovery system according to any one of claims 1 to 3, wherein the adsorbent unit operates in accordance with the carbon dioxide concentration or the number of people in the space where the air blower is installed.

5. The carbon dioxide recovery system according to any one of claims 1 to 4, wherein the adsorbent unit is suspended and supported from the rail.

6. The carbon dioxide recovery system according to claim 3, wherein when the operating state is rated operation, the adsorbent unit is moved away from the vicinity of the blower.

7. The carbon dioxide recovery system according to claim 3, wherein, when the operating state is intermediate operation, the adsorbent unit is placed near the air blower.

8. The carbon dioxide recovery system according to claim 3, wherein, when the operating state is stopped, only the fan of the blower unit is operated and the adsorbent unit is positioned near the blower unit.

9. The carbon dioxide recovery system according to any one of claims 1 to 8, wherein the distance between the adsorbent units is adjustable.

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