Carbon dioxide recovery system

Abstract

This carbon dioxide recovery system (1) comprises: a refrigerant circuit (R) that performs a refrigeration cycle, the refrigerant circuit (R) having a first adsorption member (15A) and a second adsorption member (15B) that individually adsorb carbon dioxide in target air, and a refrigerant flow path switching mechanism (90) that switches the flow of the refrigerant through a first radiator (18A) and a second radiator (18B) that are parallel to each other; a first accommodation part (11A) that forms a first space (S1) in which the first adsorption member (15A) and the first radiator (18A) are disposed; a second accommodation part (11B) that forms a second space (S2) in which the second adsorption member (15B) and the second radiator (18B) are disposed; an air flow path switching mechanism (30) that switches the air flow through the first space (S1) and the second space (S2); and a recovery unit (60) that selectively recovers carbon dioxide desorbed from the first adsorption member (15A) and the second adsorption member (15B).

Description

Carbon dioxide capture system

[0001] The present disclosure relates to carbon dioxide capture systems.

[0002] There is a system for capturing carbon dioxide from the air. The carbon dioxide capture system described in Patent Document 1 includes an adsorption plate carrying an adsorbent and a flow pipe for heating the adsorption plate. Carbon dioxide in the air is adsorbed by the adsorbent. A heating medium flowing through the flow pipe heats and regenerates the adsorbent on the adsorption plate. The carbon dioxide desorbed from the adsorbent is transported by a pump and stored.

[0003] Japanese Patent Application Laid-Open No. 2023-13169

[0004] In a carbon dioxide recovery system such as that disclosed in Patent Document 1, improvement in energy consumption efficiency is desired.

[0005] The present disclosure aims to improve the energy consumption efficiency of carbon dioxide capture systems.

[0006] The first aspect is directed to a carbon dioxide recovery system. The carbon dioxide recovery system (1) includes a first adsorption member (15A) and a second adsorption member (15B) that adsorb carbon dioxide in target air, a compressor (81), a first radiator (18A) and a second radiator (18B) that are arranged in parallel with each other, a pressure reducing mechanism (82), evaporators (36, 36A, 36B), a refrigerant flow path switching mechanism (90) that switches the flow of refrigerant in the first radiator (18A) and the second radiator (18B), and a refrigerant circuit (R) that performs a refrigeration cycle, a first adsorption unit (15A), a second adsorption unit (15B), a compressor (81), a first radiator (18A), a second radiator (18B) that are arranged in parallel with each other, a pressure reducing mechanism (82), an evaporator (36, 36A, 36B), and a refrigerant flow path switching mechanism (90) that switches the flow of refrigerant in the first radiator (18A) and the second radiator (18B). The adsorption device includes a first storage section (11A) that forms a first space (S1) in which a first adsorption member (15A) and a first radiator (18A) are disposed, a second storage section (11B) that forms a second space (S2) in which a second adsorption member (15B) and a second radiator (18B) are disposed, an air flow path switching mechanism (30) that switches the air flow in the first space (S1) and the second space (S2), and a recovery unit (60) that selectively recovers carbon dioxide desorbed from the first adsorption member (15A) and the second adsorption member (15B).

[0007] In the first aspect, the refrigerant flow path switching mechanism (90) selectively flows the refrigerant through the first radiator (18A) or the second radiator (18B). The air flow path switching mechanism (30) selectively flows the target air through the first space (S1) or the second space (S2). This allows the first adsorbent (15A) in the first space (S1) to adsorb carbon dioxide in the target air while the second radiator (18B) heats and regenerates the second adsorbent (15B), and the second adsorbent (15B) in the second space (S2) to adsorb carbon dioxide in the target air while the first radiator (18A) heats and regenerates the first adsorbent (15A). The carbon dioxide desorbed from the first adsorbent (15A) or the second adsorbent (15B) is recovered by the recovery unit (60).

[0008] In this manner, the refrigerant circuit (R) operating in a refrigeration cycle is used as a heat source for heating and regenerating the first adsorption member (15A) and the second adsorption member (15B), which can improve energy consumption efficiency compared to a heat source such as a heater.

[0009] In the second aspect, in the first aspect, the recovery unit (60) has a recovery flow path (61) for sending carbon dioxide desorbed from the first adsorption member (15A) and the second adsorption member (15B) to a predetermined recovery section (63), and a recovery switching mechanism (64) for switching the flow of carbon dioxide in the recovery flow path (61). The carbon dioxide recovery system (1) further includes a control unit (C) that controls the refrigerant flow path switching mechanism (90), the air flow path switching mechanism (30), and the recovery switching mechanism (64) so ​​as to perform a first operation in which the first radiator (18A) heats the first adsorption member (15A), the target air flows through the second space (S2), and the carbon dioxide desorbed from the first adsorption member (15A) is sent to the recovery section (63) through the recovery path (61), and a second operation in which the second radiator (18B) heats the second adsorption member (15B), the target air flows through the first space (S1), and the carbon dioxide desorbed from the second adsorption member (15B) is sent to the recovery section (63) through the recovery path (61).

[0010] In the second mode, the control unit (C) executes a first operation and a second operation. In the first operation, the refrigerant compressed by the compressor (81) dissipates heat in the first radiator (18A). As a result, the first radiator (18A) heats the first adsorption member (15A), and carbon dioxide is desorbed from the first adsorption member (15A). The carbon dioxide desorbed from the first adsorption member (15A) is sent to a predetermined recovery unit (63) via the recovery passageway (61). At the same time, in the first operation, the target air flows through the second space (S2) of the second storage unit (11B). As a result, carbon dioxide in the air is adsorbed by the second adsorption member (15B).

[0011] In the second operation, the refrigerant compressed by the compressor (81) dissipates heat in the second radiator (18B). As a result, the second radiator (18B) heats the second adsorption member (15B), and carbon dioxide is desorbed from the second adsorption member (15B). The carbon dioxide desorbed from the second adsorption member (15B) is sent to a predetermined recovery section (63) through the recovery passageway (61). At the same time, in the second operation, the target air flows through the first space (S1) of the first storage section (11A). As a result, the carbon dioxide in the air is adsorbed by the first adsorption member (15A).

[0012] In a third aspect, in the second aspect, the refrigerant flow path switching mechanism (90) is configured to switch between a first state in which the refrigerant flows through the first radiator (18A) and a second state in which the refrigerant flows through the second radiator (18B). The air flow path switching mechanism (30) is configured to switch between a third state in which a target space containing target air is connected to the first space (S1) and the target space is isolated from the second space (S2), and a fourth state in which the target space is connected to the second space (S2) and the target space is isolated from the first space (S1). The recovery switching mechanism (64) is configured to switch between a fifth state in which the first space (S1) is connected to the recovery section (63) and a sixth state in which the second space (S2) is connected to the recovery section (63). In the first operation, the control unit (C) sets the refrigerant flow path switching mechanism (90) in the first state, the air flow path switching mechanism (30) in the fourth state, and the recovery switching mechanism (64) in the fifth state. In the second operation, the control unit (C) sets the refrigerant flow path switching mechanism (90) in the second state, the air flow path switching mechanism (30) in the third state, and the recovery switching mechanism (64) in the sixth state.

[0013] In the third mode, in the first operation, the refrigerant flow path switching mechanism (90) is in the first state, the air flow path switching mechanism (30) is in the fourth state, and the recovery switching mechanism (64) is in the fifth state. As a result, the first adsorption member (15A) is heated by the first radiator (18A) through which the refrigerant flows. Carbon dioxide desorbed from the first adsorption member (15A) flows from the first space (S1) to the recovery flow path (61). At the same time, carbon dioxide in the air flowing through the second space (S2) is adsorbed by the second adsorption member (15B).

[0014] In the second operation, the refrigerant flow path switching mechanism (90) is in the second state, the air flow path switching mechanism (30) is in the third state, and the recovery switching mechanism (64) is in the sixth state. As a result, the second adsorption member (15B) is heated by the second radiator (18B) through which the refrigerant flows. Carbon dioxide desorbed from the second adsorption member (15B) flows from the second space (S2) to the recovery flow path (61). At the same time, carbon dioxide in the air flowing through the first space (S1) is adsorbed by the first adsorption member (15A).

[0015] In a fourth aspect, in any one of the first to third aspects, the refrigerant supply system further includes a downstream flow path (24) located downstream of the first storage section (11A) and the second storage section (11B). The evaporator (36) is disposed in the downstream flow path (24).

[0016] In the fourth aspect, the air used for regenerating the first adsorption member (15A) and the second adsorption member (15B) flows through the downstream flow path (24). In the downstream flow path (24), heat of the air can be imparted to the refrigerant through the evaporator (36). As a result, the heat of the air used for regenerating the first adsorption member (15A) and the second adsorption member (15B) can be recovered by the refrigerant in the refrigerant circuit (R). Therefore, this heat can be used for regenerating the first adsorption member (15A) and the second adsorption member (15B).

[0017] In a fifth aspect, in any one of the first to third aspects, the evaporator (36) further includes an upstream flow path (21) located upstream of the first storage section (11A) and the second storage section (11B).

[0018] In the fifth aspect, in the upstream flow path (21), the air cooled in the evaporator (36) flows through the first adsorption member (15A) and the second adsorption member (15B). The temperature of the air passing through the first adsorption member (15A) and the second adsorption member (15B) decreases, thereby improving the efficiency of carbon dioxide adsorption in the first adsorption member (15A) and the second adsorption member (15B).

[0019] In the sixth aspect, the fifth aspect further includes a control unit (C) for controlling the rotation speed of the compressor (81) so that the evaporator (36) cools the air to a temperature equal to or lower than the dew point temperature.

[0020] In the sixth aspect, the air dehumidified by the evaporator (36) flows through the first adsorption member (15A) and the second adsorption member (15B), thereby preventing the first adsorption member (15A) and the second adsorption member (15B) from being deteriorated by moisture in the air.

[0021] In a seventh aspect, in any one of the first to sixth aspects, the refrigerant circuit (R) includes a single junction flow path (87) connected to both a liquid side end of the first radiator (18A) and a liquid side end of the second radiator (18B), and the pressure reduction mechanism (82) is provided in the junction flow path (87).

[0022] In the seventh aspect, the number of pressure reducing mechanisms (82) can be reduced, and the refrigerant circuit (R) can be simplified.

[0023] In an eighth aspect, in any one of the first to seventh aspects, the refrigerant circuit (R) has an auxiliary radiator (73) that heats water to generate water vapor. The carbon dioxide recovery system further includes a supply path (71) that supplies the water vapor generated in the auxiliary radiator (73) to the inside of the first space (S1) and the second space (S2).

[0024] In the eighth aspect, the water vapor generated in the auxiliary radiator (73) can be supplied to the periphery of the first adsorption member (15A) or the second adsorption member (15B) being regenerated via the supply path (71), thereby improving the efficiency of carbon dioxide regeneration in the first adsorption member (15A) or the second adsorption member (15B).

[0025] A ninth aspect is any one of the second to eighth aspects, wherein the refrigerant circuit (R) has an auxiliary evaporator (75) arranged in the recovery passageway (61).

[0026] In the ninth aspect, the heat of the carbon dioxide flowing through the recovery passageway (61) can be recovered into the refrigerant in the refrigerant circuit (R) via the evaporator (36). Therefore, this heat can be used to regenerate the first adsorption member (15A) and the second adsorption member (15B).

[0027] In a tenth aspect, the carbon dioxide capture system further includes a first flow path (22A, 23A, 26A, 27A) capable of communicating with the first space (S1) of the first storage unit (11A) and a second flow path (22B, 23B, 26B, 27B) capable of communicating with the second space (S2) of the second storage unit (11B). The refrigerant circuit (R) includes, as evaporators, a first evaporator (36A) and a second evaporator (36B) arranged in parallel with each other. The first evaporator (36A) is arranged in the first flow path (22A, 23A, 26A, 27A). The second evaporator (36B) is arranged in the second flow path (22B, 23B, 26B, 27B).

[0028] In the tenth aspect, when carbon dioxide in the target air is adsorbed by the first adsorption member (15A) in the first space (S1), the refrigerant in the first evaporator (36A) can be evaporated by the air flowing through the first flow paths (22A, 23A, 26A, 27A). Therefore, heat imparted to the refrigerant in the first evaporator (36A) can be utilized for heating the second adsorption member (15B) by the second radiator (18B). When carbon dioxide in the target air is adsorbed by the second adsorption member (15B) in the second space (S2), the refrigerant in the second evaporator (36B) can be evaporated by the air flowing through the second flow paths (22B, 23B, 26B, 27B). Therefore, heat imparted to the refrigerant in the second evaporator (36B) can be utilized for heating the first adsorption member (15A) by the first radiator (18A).

[0029] In an eleventh aspect, in the tenth aspect, the recovery unit (60) includes a recovery flow path (61) for sending carbon dioxide desorbed from the first adsorption member (15A) and the second adsorption member (15B) to a predetermined recovery section (63), and a recovery switching mechanism (64) for switching the flow of carbon dioxide in the recovery flow path (61). The carbon dioxide recovery system includes a control section (C). The control unit (C) controls the refrigerant flow path switching mechanism (90), the air flow path switching mechanism (30), and the recovery switching mechanism (64) to perform a first operation in which the first radiator (18A) heats the first adsorption member (15A), the target air flows through the second space (S2) and the second evaporator (36B) of the second flow paths (22B, 23B, 26B, 27B), and carbon dioxide desorbed from the first adsorption member (15A) is sent to the recovery section (63) through the recovery flow path (61), and a second operation in which the second radiator (18B) heats the second adsorption member (15B), the target air flows through the first space (S1) and the first evaporator (36A) of the first flow paths (22A, 23A, 26A, 27A), and carbon dioxide desorbed from the second adsorption member (15B) is sent to the recovery section (63) through the recovery flow path (61).

[0030] In an eleventh aspect, the control unit (C) executes a first operation and a second operation. In the first operation, refrigerant compressed by the compressor (81) dissipates heat in the first radiator (18A) and evaporates in the second evaporator (36B). In the first operation, the first radiator (18A) heats the first adsorption member (15A), causing carbon dioxide to desorb from the first adsorption member (15A). The carbon dioxide desorbed from the first adsorption member (15A) is sent to a predetermined recovery unit (63) via the recovery flow path (61). At the same time, in the first operation, target air flows through the second space (S2) and the second flow paths (22B, 23B, 26B, 27B) of the second storage unit (11B). As a result, carbon dioxide in the air is adsorbed by the second adsorption member (15B). In the second evaporator (36B) of the second flow path (22B, 23B, 26B, 27B), heat of the target air is imparted to the refrigerant.

[0031] In the second operation, the refrigerant compressed by the compressor (81) dissipates heat in the second radiator (18B) and evaporates in the first evaporator (36A). In the second operation, the second radiator (18B) heats the second adsorption member (15B), causing carbon dioxide to desorb from the second adsorption member (15B). The carbon dioxide desorbed from the second adsorption member (15B) is sent to a predetermined recovery section (63) through the recovery flow path (61). Simultaneously, in the second operation, the target air flows through the first space (S1) of the first storage section (11A) and the second flow paths (22B, 23B, 26B, 27B). As a result, carbon dioxide in the air is adsorbed by the first adsorption member (15A). In the first evaporator (36A) of the first flow paths (22A, 23A, 26A, 27A), heat from the target air is imparted to the refrigerant.

[0032] In a twelfth aspect, in the eleventh aspect, the refrigerant flow path switching mechanism (90) is configured to switch between a first state in which the refrigerant flows through the first radiator (18A) and the second evaporator (36B), and a second state in which the refrigerant flows through the second radiator (18B) and the first evaporator (36A). The air flow path switching mechanism (30) is configured to switch between a third state in which the first space (S1) is connected to a target space containing the target air and the first flow path (22A, 23A, 26A, 27A) and the second space (S2) is disconnected from the target space and the second flow path (22B, 23B, 26B, 27B) and a fourth state in which the second space (S2) is connected to the target space and the second flow path (22B, 23B, 26B, 27B) and the first space (S1) is disconnected from the target space and the first flow path (22A, 23A, 26A, 27A). The recovery switching mechanism (64) is configured to switch between a fifth state in which the first space (S1) is connected to the recovery section (63) and a sixth state in which the second space (S2) is connected to the recovery section (63). In a first operation, the control unit (C) sets the refrigerant flow path switching mechanism (90) in a first state, the air flow path switching mechanism (30) in a fourth state, and the recovery switching mechanism (64) in a fifth state, and in a second operation, sets the refrigerant flow path switching mechanism (90) in a second state, the air flow path switching mechanism (30) in a third state, and the recovery switching mechanism (64) in a sixth state.

[0033] In the twelfth aspect, in the first operation, the refrigerant flow path switching mechanism (90) is in the first state, the air flow path switching mechanism (30) is in the fourth state, and the recovery switching mechanism (64) is in the fifth state. As a result, the first adsorption member (15A) is heated by the first radiator (18A) through which the refrigerant flows, and heat of the target air is imparted to the refrigerant in the second evaporator (36B) of the second flow path (22B, 23B, 26B, 27B). Carbon dioxide desorbed from the first adsorption member (15A) flows from the first space (S1) to the recovery flow path (61). At the same time, carbon dioxide in the air flowing through the second space (S2) is adsorbed by the second adsorption member (15B).

[0034] In the second operation, the refrigerant flow path switching mechanism (90) is in the second state, the air flow path switching mechanism (30) is in the third state, and the recovery switching mechanism (64) is in the sixth state. As a result, the second adsorption member (15B) is heated by the second radiator (18B) through which the refrigerant flows, and heat of the target air is imparted to the refrigerant in the first evaporator (36A) of the first flow path (22A, 23A, 26A, 27A). Carbon dioxide desorbed from the second adsorption member (15B) flows from the second space (S2) to the recovery flow path (61). At the same time, carbon dioxide in the air flowing through the first space (S1) is adsorbed by the first adsorption member (15A).

[0035] A thirteenth aspect is any one of the tenth to twelfth aspects, wherein the first flow paths (23A, 27A) are located downstream of the first space (S1), and the second flow paths (23B, 27B) are located downstream of the second space (S2).

[0036] In the thirteenth aspect, the air used to regenerate the first adsorption member (15A) flows from the first space (S1) through the first flow path (23A, 27A). Alternatively, the air used to regenerate the second adsorption member (15B) flows from the second space (S2) through the second flow path (23B, 27B). Therefore, the heat of the air used to regenerate the first adsorption member (15A) or the second adsorption member (15B) can be recovered into the refrigerant in the refrigerant circuit (R) via the first evaporator (36A) or the second evaporator (36B). Therefore, this heat can be used to regenerate the first adsorption member (15A) or the second adsorption member (15B).

[0037] A fourteenth aspect is any one of the tenth to twelfth aspects, wherein the first flow path (22A, 26A) is located upstream of the first space (S1). The second flow path (22B, 26B) is located upstream of the second space (S2). Therefore, air cooled in the first evaporator (36A) of the first flow path (22A, 26A) flows through the first adsorption member (15A). Alternatively, air cooled in the second evaporator (36B) of the second flow path (22B, 26B) flows through the second adsorption member (15B). The temperature of the air passing through the first adsorption member (15A) or the second adsorption member (15B) decreases, thereby improving the carbon dioxide adsorption efficiency of the first adsorption member (15A) or the second adsorption member (15B).

[0038] FIG. 1 is a diagram of the overall configuration of a carbon dioxide capture system. FIG. 2 is a piping diagram of a refrigeration cycle apparatus. FIG. 3 is a block diagram of major equipment. FIG. 4 is a timing chart showing the operation of each adsorption unit. FIG. 5 is a diagram corresponding to FIG. 1 for explaining a first operation. FIG. 6 is a diagram corresponding to FIG. 1 for explaining a second operation. FIG. 7 is a diagram of the overall configuration of a carbon dioxide capture system of Modification 1. FIG. 8 is a piping diagram of a refrigeration cycle apparatus of Modification 1. FIG. 9 is a timing chart showing the operation of each adsorption unit of Modification 1. FIG. 10 is a diagram of the overall configuration of a carbon dioxide capture system of Modification 2. FIG. 11 is a diagram of the overall configuration of a carbon dioxide capture system of Modification 3. FIG. 12 is a piping diagram of a refrigeration cycle apparatus of Modification 3. FIG. 13 is a diagram of the overall configuration of a carbon dioxide capture system of Modification 4. FIG. 14 is a diagram of the overall configuration of a carbon dioxide capture system of Modification 5. FIG. 15 is a piping diagram of a refrigeration cycle apparatus of Modification 5. FIG. 16 is a diagram of the overall configuration of a carbon dioxide capture system of Modification 6.

[0039] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the embodiments shown below, and various modifications are possible within the scope of the technical concept of the present disclosure. Since the drawings are intended to conceptually explain the present disclosure, dimensions, ratios, or numbers may be exaggerated or simplified as necessary to facilitate understanding.

[0040] (1) Overall Configuration An embodiment of the present disclosure is a carbon dioxide capture system (1). The carbon dioxide capture system (1) of this example captures carbon dioxide from the air. The carbon dioxide capture system (1) of this example constitutes a DAC (Direct Air Capture) system that separates and captures carbon dioxide directly from outdoor air.

[0041] The carbon dioxide capture system (1) shown in Fig. 1 includes an adsorption device (10), a capture unit (60), a steam supply unit (70), and a controller (C). As shown in Fig. 2, the carbon dioxide capture system (1) includes a refrigeration cycle device (80) having a refrigerant circuit (R).

[0042] The adsorption device (10) includes a plurality of adsorption units (U1, U2). Each adsorption unit (U1, U2) includes an adsorption member (15A, 15B). Each adsorption unit (U1, U2) performs an adsorption operation of adsorbing carbon dioxide in the outdoor air onto the adsorption member (15A, 15B) and a regeneration operation of regenerating and desorbing the carbon dioxide adsorbed onto the adsorption member (15A, 15B).

[0043] The recovery unit (60) is a device for recovering carbon dioxide desorbed from the adsorption members (15A, 15B). The steam supply unit (70) is a device for supplying steam to the adsorption members (15A, 15B) during regeneration. The refrigeration cycle device (80) is a heat source for heating and regenerating the adsorption members (15A, 15B). The controller (C) shown in FIG. 3 controls the adsorption device (10), the recovery unit (60), the steam supply unit (70), and the refrigeration cycle device (80).

[0044] (2) Adsorption Device The adsorption device (10) has a first adsorption unit (U1) and a second adsorption unit (U2) as a plurality of adsorption units. The number of the plurality of adsorption units (U1, U2) is merely an example, and as will be described in detail later, the number may be three or more. The first adsorption unit (U1) has a first casing (11A), a first adsorption member (15A), and a first radiator (18A). The second adsorption unit (U2) has a second casing (11B), a second adsorption member (15B), and a second radiator (18B).

[0045] The adsorption device (10) includes an air flow path (20), a fan (35) for transporting air through the air flow path (20), an air flow path switching mechanism (30), and an evaporator (36).

[0046] (2-1) Casing The first casing (11A) is an example of a first housing portion, and the second casing (11B) is an example of a second housing portion. The first casing (11A) and the second casing (11B) are each formed to have a hollow shape. A first space (S1) is formed inside the first casing (11A), and a second space (S2) is formed inside the second casing (11B).

[0047] The first casing (11A) is formed with a first inlet (I1) and a first outlet (O1). The first inlet (I1) is an opening located on the upstream side of the first space (S1), and the first outlet (O1) is an opening located on the downstream side of the first space (S1). The second casing (11B) is formed with a second inlet (I2) and a second outlet (O2). The second inlet (I2) is an opening located on the upstream side of the second space (S2), and the second outlet (O2) is an opening located on the downstream side of the second space (S2).

[0048] (2-2) Adsorption Member The first adsorption member (15A) is disposed in the first space (S1) of the first casing (11A), and the second adsorption member (15B) is disposed in the second space (S2) of the second casing (11B).

[0049] Each of the adsorption members (15A, 15B) has a base material through which air can pass and an adsorbent supported on the base material. The base material is made of a ceramic material having a plurality of pores, a metal material having a plurality of pores, a porous material having a plurality of pores, metal fiber, carbon fiber, or the like. The thermal conductivity of the base material is preferably 1 [W / (m·K)] or more.

[0050] The adsorbent has the property of adsorbing carbon dioxide. The adsorbent is, for example, an amine-based substance. The higher the temperature of the adsorbent, the easier it is to desorb carbon dioxide, and the lower the temperature, the easier it is to adsorb carbon dioxide. Here, "adsorption" includes not only carbon dioxide being adsorbed onto the surface of a solid or liquid, but also carbon dioxide being absorbed into the interior of a solid or liquid. Furthermore, "adsorption" includes not only physical adsorption but also chemical adsorption. The adsorbent (60) is formed of a liquid film.

[0051] (2-3) Radiator The first radiator (18A) is disposed in the first space (S1) of the first casing (11A). The first radiator (18A) is disposed in proximity to the first adsorption member (15A). The first adsorption member (15A) is in contact with the first radiator (18A). The first radiator (18A) heats the first adsorption member (15A) with the refrigerant flowing therethrough. The second radiator (18B) is disposed in proximity to the second adsorption member (15B). The second adsorption member (15B) is in contact with the second radiator (18B). The second radiator (18B) heats the second adsorption member (15B) with the refrigerant flowing therethrough.

[0052] (2-4) Air Flow Channel The air flow channel (20) is a flow channel formed, for example, by a duct, and includes an intake duct (21), a first inlet branch duct (22A), a second inlet branch duct (22B), a first outlet branch duct (23A), a second outlet branch duct (23B), and an exhaust duct (24).

[0053] One end (inlet end) of the suction duct (21) communicates with the outdoor space. The other end (outlet end) of the suction duct (21) is connected to one end (inlet end) of a first inlet branch duct (22A) and one end (inlet end) of a second inlet branch duct (22B). The other end (outlet end) of the first inlet branch duct (22A) is connected to the first inlet (I1). The other end (outlet end) of the second inlet branch duct (22B) is connected to the second inlet (I2). One end (inlet end) of the first outlet branch duct (23A) is connected to the first outlet (O1). One end (inlet end) of the second outlet branch duct (23B) is connected to the second outlet (O2). The other end (outlet end) of the first outlet branch duct (23A) and the other end (outlet end) of the second outlet branch duct (23B) are connected to one end (inlet end) of the exhaust duct (24). The other end (outlet end) of the exhaust duct (24) communicates with the outdoor space. The suction duct (21) is an example of an upstream flow path. The exhaust duct (24) is an example of a downstream flow path.

[0054] (2-5) Fan The fan (35) is disposed inside the exhaust duct (24). The fan (35) is, for example, a propeller fan. The fan (35) may also be disposed in the intake duct (21).

[0055] (2-6) Air Flow Channel Switching Mechanism The air flow channel switching mechanism (30) switches the air flow between the first space (S1) and the second space (S2). The air flow channel switching mechanism (30) is configured to switch between a third state in which the target space (outdoor space) containing the outdoor air, which is the target air, is communicated with the first space (S1) and the outdoor space is blocked from the second space (S2), and a fourth state in which the outdoor space is communicated with the second space (S2) and the air flow channel (20) is blocked from the first space (S1).

[0056] Specifically, the air flow path switching mechanism (30) has a first inlet-side damper (31), a first outlet-side damper (32), a second inlet-side damper (33), and a second outlet-side damper (34). The first inlet-side damper (31) and the first outlet-side damper (32) are provided in the first adsorption unit (U1). The second inlet-side damper (33) and the second outlet-side damper (34) are provided in the second adsorption unit (U2).

[0057] The first inlet damper (31) opens and closes the first inlet (I1). The second inlet damper (33) opens and closes the second inlet (I2). The first outlet damper (32) opens and closes the first outlet (O1). The second outlet damper (34) opens and closes the second outlet (O2). In Fig. 1, the dampers in the open state are shown by solid lines, and the dampers in the closed state are shown by dashed lines.

[0058] When the air flow path switching mechanism (30) is in the third state, the first inlet-side damper (31) and the first outlet-side damper (32) are in an open state, and the second inlet-side damper (33) and the second outlet-side damper (34) are in a closed state. When the air flow path switching mechanism (30) is in the third state, air in the air flow path (20) flows through the first space (S1), while the second space (S2) is blocked from the air flow path (20).

[0059] When the air flow path switching mechanism (30) is in the fourth state, the second inlet-side damper (33) and the second outlet-side damper (34) are in the open state, and the first inlet-side damper (31) and the first outlet-side damper (32) are in the closed state. When the air flow path switching mechanism (30) is in the fourth state, air in the air flow path (20) flows through the second space (S2), while the first space (S1) is blocked from the air flow path (20).

[0060] (2-7) Evaporator The evaporator (36) of this embodiment is disposed in the discharge duct (24). The evaporator (36) is disposed in the air flow path (20) downstream of the first adsorption unit (U1) and the second adsorption unit (U2). The evaporator (36) exchanges heat between the refrigerant flowing therein and the air flowing through the discharge duct (24). The evaporator (36) recovers residual heat of the air discharged to the outside of the room as heat of evaporation of the refrigerant.

[0061] (3) Recovery Unit The recovery unit (60) selectively recovers carbon dioxide desorbed from the first adsorption member (15A) and the second adsorption member (15B). The recovery unit (60) includes a recovery flow path (61), a pump (62), and a recovery tank (63) serving as a recovery section.

[0062] The recovery flow path (61) is a flow path for sending carbon dioxide desorbed from the first adsorption member (15A) and the second adsorption member (15B) to the recovery tank (63). The recovery flow path (61) has a first suction path (61a), a second suction path (61b), and a main flow path (61c). One end (inlet end) of the first suction path (61a) is connected to the first casing (11A) and communicates with the first space (S1). One end (inlet end) of the second suction path (61b) is connected to the second casing (11B) and communicates with the second space (S2). One end (inlet end) of the recovery flow path (61) is connected to the other end (outlet end) of the first suction path (61a) and the other end (outlet end) of the second suction path (61b). The other end (outlet end) of the main flow path (61c) is connected to the recovery tank (63).

[0063] The pump (62) is provided in the recovery flow path (61). The pump (62) transports carbon dioxide in the recovery flow path (61). The pump (62) also serves as a pressure reducing device that reduces the pressure in the first space (S1) and the second space (S2). The recovery tank (63) is a storage container that stores the carbon dioxide that has flowed out through the recovery flow path (61).

[0064] The recovery unit (60) has a recovery switching mechanism (64) that switches the flow of carbon dioxide in the recovery flow path (61). The recovery switching mechanism (64) is configured to switch between a fifth state in which the first space (S1) communicates with the recovery tank (63) side (the outlet side of the recovery flow path (61)), and a sixth state in which the second space (S2) communicates with the recovery tank (63) side (the outlet side of the recovery flow path (61)).

[0065] The recovery switching mechanism (64) has a first recovery valve (64a) and a second recovery valve (64b). The first recovery valve (64a) is provided in the first suction passage (61a). The second recovery valve (64b) is provided in the second suction passage (61b). The first recovery valve (64a) and the second recovery valve (64b) are configured as on-off valves such as solenoid on-off valves, but may also be flow rate control valves. When the recovery switching mechanism (64) is in the fifth state, the first recovery valve (64a) is opened and the second recovery valve (64b) is closed. When the recovery switching mechanism (64) is in the sixth state, the second recovery valve (64b) is opened and the first recovery valve (64a) is closed.

[0066] (4) Steam Supply Unit The steam supply unit (70) supplies the generated steam to the adsorption units (U1, U2) in the regenerating operation. The steam supply unit (70) includes a supply path (71), a generation tank (72), and an auxiliary radiator (73).

[0067] The supply channel (71) has a first inlet channel (71a), a second inlet channel (71b), and a main supply channel (71c). One end (inlet end) of the main supply channel (71c) is connected to the top of the refinery tank (72). One end (inlet end) of the first inlet channel (71a) and one end (inlet end) of the second inlet channel (71b) are connected to the other end (outlet end) of the main supply channel (71c). The other end (outlet end) of the first inlet channel (71a) is connected to the first casing (11A) and communicates with the first space (S1). The other end (outlet end) of the second inlet channel (71b) is connected to the second casing (11B) and communicates with the second space (S2).

[0068] The first introduction passage (71a) is provided with a first introduction valve (74a), and the second introduction passage (71b) is provided with a second introduction valve (74b). The first introduction valve (74a) and the second introduction valve (74b) are configured as on-off valves such as solenoid on-off valves, but may also be flow rate control valves.

[0069] The production tank (72) is a container for generating steam. Water is supplied from a predetermined water source to the inside of the production tank (72). The auxiliary radiator (73) is disposed inside the production tank (72). The auxiliary radiator (73) generates steam by heating the water in the production tank (72). The steam generated in the production tank (72) is supplied to the adsorption units (U1, U2) in the regeneration operation via the supply path (71).

[0070] (5) Refrigeration Cycle Device As shown in Fig. 2, the refrigeration cycle device (80) has a refrigerant circuit (R) filled with a refrigerant. The refrigerant circuit (R) performs a refrigeration cycle by circulating the refrigerant. The refrigerant circuit (R) has a compressor (81), a first radiator (18A), a second radiator (18B), an auxiliary radiator (73), an expansion valve (82), and an evaporator (36).

[0071] The compressor (81) compresses the drawn refrigerant and discharges the compressed refrigerant. The first radiator (18A) and the second radiator (18B) are provided in parallel to each other in the refrigerant circuit (R). The auxiliary radiator (73) of this embodiment is provided in parallel to the first radiator (18A) and the second radiator (18B) in the refrigerant circuit (R). Specifically, the high-pressure line of the refrigerant circuit (R) has a first high-pressure flow path (85a), a second high-pressure flow path (85b), and an auxiliary high-pressure flow path (86), which are parallel to each other. The first radiator (18A) is provided in the first high-pressure flow path (85a), the second radiator (18B) is provided in the second high-pressure flow path (85b), and the auxiliary radiator (73) is provided in the auxiliary high-pressure flow path (86). The auxiliary radiator (73) may be provided in series with the first radiator (18A) and the second radiator (18B) in the refrigerant circuit (R).

[0072] The refrigerant circuit (R) has a junction flow path (87) connecting the liquid side end of the first radiator (18A) and the liquid side end of the second radiator (18B). The junction flow path (87) is a liquid line connecting the first high-pressure flow path (85a), the second high-pressure flow path (85b), and the third high-pressure flow path (85c). An expansion valve (82) is provided in the junction flow path (87). The expansion valve (82) is an example of a pressure reducing mechanism, and may be, for example, an electronic expansion valve. The evaporator (36) is provided between the expansion valve (82) and the suction portion of the compressor (81) in the refrigerant circuit (R). An auxiliary on-off valve (91) is provided in the third high-pressure flow path (85c). The auxiliary on-off valve (91) is an electromagnetic on-off valve, but may also be a flow control valve.

[0073] The refrigerant circuit (R) has a refrigerant flow path switching mechanism (90) that switches the flow of the refrigerant. The refrigerant flow path switching mechanism (90) is configured to switch between a first state in which the refrigerant flows through the first radiator (18A) and a second state in which the refrigerant flows through the second radiator (18B).

[0074] The refrigerant flow path switching mechanism (90) has a first on-off valve (90a) and a second on-off valve (90b). The first on-off valve (90a) is provided in the first high-pressure flow path (85a). The second on-off valve (90b) is provided in the second high-pressure flow path (85b). The first on-off valve (90a) and the second on-off valve (90b) are electromagnetic on-off valves, but may be flow rate control valves. When the refrigerant flow path switching mechanism (90) is in the first state, the first on-off valve (90a) is opened and the second on-off valve (90b) is closed. When the refrigerant flow path switching mechanism (90) is in the second state, the second on-off valve (90b) is opened and the first on-off valve (90a) is closed.

[0075] (6) Controller The controller (C) shown in FIG. 3 includes a microcomputer and a memory device that stores software for operating the microcomputer.

[0076] The controller (C) controls the open / close states of the dampers (31, 32, 33, 34), the ON / OFF state of the fan (35), the ON / OFF state of the pump (62), the open / close states of the recovery valves (64a, 64b), the open / close states of the introduction valves (74a, 74b), the ON / OFF state of the compressor (81), the opening degree of the expansion valve (82), and the open / close states of the on-off valves (90a, 90b). The controller (C) controls the rotation speed of the compressor (81). The controller (C) may also control the rotation speed of the fan (35) or the pump (62).

[0077] (7) Operation Operation of the carbon dioxide capture system (1) will be described. As shown in FIG. 4 , the carbon dioxide capture system (1) alternately performs a first operation and a second operation. The first operation is an example of a first operation. In the first operation, the first adsorption unit (U1) performs a regeneration operation while the second adsorption unit (U2) performs an adsorption operation. The second operation is an example of a second operation. In the second operation, the first adsorption unit (U1) performs an adsorption operation while the second adsorption unit (U2) performs a regeneration operation.

[0078] In other words, the first suction unit (U1) alternates between regeneration and suction. The second suction unit (U2) alternates between regeneration and suction. In this example, the execution time T1 of the regeneration operation performed by each suction unit (U1, U2) is the same as the execution time T2 of the suction operation performed by each suction unit (U1, U2).

[0079] The controller (C) operates the fan (35), the pump (62), and the compressor (81) in the first operation and the second operation, and adjusts the opening of the expansion valve (82) as appropriate in the first operation and the second operation.

[0080] 5 , the controller (C) controls the refrigerant flow path switching mechanism (90), the air flow path switching mechanism (30), and the recovery switching mechanism (64) so ​​that the first radiator (18A) heats the first adsorption member (15A), the air in the air flow path (20) flows through the second space (S2), and the carbon dioxide desorbed from the first adsorption member (15A) is sent to the recovery tank (63) through the recovery flow path (61). Specifically, in the first operation, the controller (C) sets the refrigerant flow path switching mechanism (90) to the first state, the air flow path switching mechanism (30) to the fourth state, and the recovery switching mechanism (64) to the fifth state. More specifically, in the first operation, the controller (C) closes the first inlet damper (31) and the first outlet damper (32), opens the second inlet damper (33) and the second outlet damper (34), opens the first recovery valve (64a), closes the second recovery valve (64b), opens the first introduction valve (74a), closes the second introduction valve (74b), opens the first opening / closing valve (90a), closes the second opening / closing valve (90b), and opens the auxiliary opening / closing valve (91).

[0081] In the refrigerant circuit (R) shown in FIG. 2 , refrigerant compressed in the compressor (81) is divided into a first high-pressure flow path (85a) and an auxiliary high-pressure flow path (86). The refrigerant in the first high-pressure flow path (85a) dissipates heat to the air in the first space (S1) while flowing through the first heat radiator (18A). The refrigerant in the auxiliary high-pressure flow path (86) dissipates heat to the surrounding water while flowing through the auxiliary heat radiator (73). The refrigerant that has passed through the first high-pressure flow path (85a) and the auxiliary high-pressure flow path (86) merges in a junction flow path (87) and is then decompressed by an expansion valve (82). The decompressed refrigerant absorbs heat from the surrounding air while flowing through the evaporator (36) and evaporates. The refrigerant that has evaporated in the evaporator (36) is drawn into the compressor (81) and compressed again.

[0082] In the first operation, outdoor air from the outdoor space flows through the suction duct (21) and the second inlet branch duct (22B) in this order, and then flows into the second space (S2) of the second casing (11B). In the second space (S2), carbon dioxide in the air is adsorbed by the second adsorption member (15B). The air that has passed through the second adsorption member (15B) flows through the second outlet branch duct (23B) and the exhaust duct (24) in this order. In the evaporator (36) in the exhaust duct (24), heat is exchanged between the air and the refrigerant, and the heat of the air is recovered as the heat of evaporation of the refrigerant. The air in the exhaust duct (24) is exhausted to the outdoor space.

[0083] In the first operation, the first radiator (18A) heats the first adsorption member (15A). As a result, carbon dioxide is desorbed from the first adsorption member (15A). When the pump (62) is operated, a negative pressure is created in the first space (S1). As a result, desorption of carbon dioxide from the first adsorption member (15A) is promoted.

[0084] In the generation tank (72), water heated by the auxiliary radiator (73) is converted into water vapor. The water vapor generated in the generation tank (72) flows into the first space (S1) through the supply channel (71). The supply of water vapor to the periphery of the first adsorption member (15A) promotes desorption of carbon dioxide in the first adsorption member (15A).

[0085] The carbon dioxide desorbed from the first adsorption member (15A) is sent to the recovery tank (63) through the recovery passageway (61). The carbon dioxide is stored in the recovery tank (63).

[0086] 6 , the controller (C) controls the refrigerant flow path switching mechanism (90), the air flow path switching mechanism (30), and the recovery switching mechanism (64) so ​​that the second radiator (18B) heats the second adsorption member (15B), the air in the air flow path (20) flows through the first space (S1), and the carbon dioxide desorbed from the second adsorption member (15B) is sent to the recovery tank (63) through the recovery flow path (61). Specifically, in the second operation, the controller (C) sets the refrigerant flow path switching mechanism (90) to the second state, the air flow path switching mechanism (30) to the fifth state, and the recovery switching mechanism (64) to the sixth state. More specifically, in the second operation, the controller (C) opens the first inlet damper (31) and the first outlet damper (32), closes the second inlet damper (33) and the second outlet damper (34), closes the first recovery valve (64a), opens the second recovery valve (64b), closes the first introduction valve (74a), opens the second introduction valve (74b), closes the first opening / closing valve (90a), opens the second opening / closing valve (90b), and opens the auxiliary opening / closing valve (91).

[0087] In the refrigerant circuit (R) shown in FIG. 2 , refrigerant compressed in the compressor (81) is divided into a second high-pressure flow path (85b) and an auxiliary high-pressure flow path (86). The refrigerant in the second high-pressure flow path (85b) dissipates heat to the air in the second space (S2) while flowing through the second radiator (18B). The refrigerant in the auxiliary high-pressure flow path (86) dissipates heat to the surrounding water while flowing through the auxiliary radiator (73). The refrigerant that has passed through the second high-pressure flow path (85b) and the auxiliary high-pressure flow path (86) merges in a junction flow path (87) and is then decompressed by an expansion valve (82). The decompressed refrigerant absorbs heat from the surrounding air while flowing through the evaporator (36) and evaporates. The refrigerant that has evaporated in the evaporator (36) is drawn into the compressor (81) and compressed again.

[0088] In the second operation, outdoor air from the outdoor space flows through the suction duct (21) and the first inlet branch duct (22A) in this order, and then flows into the first space (S1) of the first casing (11A). In the first space (S1), carbon dioxide in the air is adsorbed by the first adsorption member (15A). The air that has passed through the first adsorption member (15A) flows through the first outlet branch duct (23A) and the exhaust duct (24) in this order. In the evaporator (36) in the exhaust duct (24), heat is exchanged between the air and the refrigerant, and the heat of the air is recovered as the heat of evaporation of the refrigerant. The air in the exhaust duct (24) is exhausted to the outdoor space.

[0089] In the second operation, the second radiator (18B) heats the second adsorption member (15B). As a result, carbon dioxide is desorbed from the second adsorption member (15B). When the pump (62) is operated, the second space (S2) is brought into negative pressure. As a result, desorption of carbon dioxide from the second adsorption member (15B) is promoted.

[0090] In the generation tank (72), water heated by the auxiliary radiator (73) is converted into water vapor. The water vapor generated in the generation tank (72) flows into the second space (S2) through the supply channel (71). The supply of water vapor to the periphery of the second adsorption member (15B) promotes desorption of carbon dioxide in the second adsorption member (15B).

[0091] The carbon dioxide desorbed from the second adsorption member (15B) is sent to the recovery tank (63) through the recovery passageway (61). The carbon dioxide is stored in the recovery tank (63).

[0092] (8) Features (8-1) The carbon dioxide recovery system (1) includes a refrigerant circuit (R) that performs a refrigeration cycle and includes a compressor (81), a first radiator (18A) and a second radiator (18B) that are arranged in parallel with each other, an expansion valve (82), an evaporator (36), and a refrigerant flow path switching mechanism (90) that switches the flow of refrigerant in the first radiator (18A) and the second radiator (18B). The carbon dioxide recovery system (1) includes a first storage section (11A) that forms a first space (S1) in which a first adsorption member (15A) and a first radiator (18A) are disposed, a second storage section (11B) that forms a second space (S2) in which a second adsorption member (15B) and a second radiator (18B) are disposed, an air flow path switching mechanism (30) that switches the air flow in the first space (S1) and the second space (S2), and a recovery unit (60) that selectively recovers carbon dioxide desorbed from the first adsorption member (15A) and the second adsorption member (15B).

[0093] In this configuration, the refrigerant flow path switching mechanism (90) selectively flows the refrigerant through the first radiator (18A) or the second radiator (18B). The air flow path switching mechanism (30) selectively flows the outdoor air through the first space (S1) or the second space (S2). This allows the first adsorbent (15A) in the first space (S1) to adsorb carbon dioxide in the outdoor air while the second radiator (18B) heats and regenerates the second adsorbent (15B), and the second adsorbent (15B) in the second space (S2) to adsorb carbon dioxide in the outdoor air while the first radiator (18A) heats and regenerates the first adsorbent (15A). The carbon dioxide desorbed from the first adsorbent (15A) or the second adsorbent (15B) is recovered by the recovery unit (60).

[0094] In this configuration, the refrigerant circuit (R) that operates in a refrigeration cycle is used as a heat source for heating and regenerating the first adsorption member (15A) and the second adsorption member (15B), which can improve energy consumption efficiency compared to a heat source such as a heater.

[0095] (8-2) The carbon dioxide recovery system (1) includes a controller (C) that controls the refrigerant flow path switching mechanism (90), the air flow path switching mechanism (30), and the recovery switching mechanism (64) so ​​as to perform a first operation in which the first radiator (18A) heats the first adsorption member (15A), outdoor air flows through the second space (S2) of the second casing (11B), and carbon dioxide desorbed from the first adsorption member (15A) is sent to the recovery tank (63) through the recovery path (61), and a second operation in which the second radiator (18B) heats the second adsorption member (15B), outdoor air flows through the first space (S1) of the first casing (11A), and carbon dioxide desorbed from the second adsorption member (15B) is sent to the recovery tank (63) through the recovery path (61).

[0096] In this configuration, the first operation and the second operation can be performed by the controller (C). In this case, it is preferable that the controller (C) switches the refrigerant flow between the first radiator (18A) and the second radiator (18B) using the refrigerant flow path switching mechanism (90) while continuing to operate the compressor (81). This reduces the number of times the compressor (81) is started and stopped, thereby improving energy consumption efficiency. Reducing the number of times the compressor (81) is started and stopped also extends the life of the compressor (81).

[0097] (8-3) The evaporator (36) of the refrigerant circuit (R) is disposed in the exhaust duct (24), which is the downstream flow path. In the first and second operations, the air that has passed through the adsorption members (15A, 15B) immediately after the regeneration operation passes through the evaporator (36). Therefore, relatively high-temperature air flows through the evaporator (36). Therefore, the heat of this high-temperature air can be utilized as the heat of evaporation of the refrigerant flowing through the evaporator (36). In other words, the heat of this air can be recovered by the refrigerant in the refrigerant circuit (R) via the evaporator (36), and this heat can be utilized as heat for regeneration of the adsorption members (15A, 15B) during the regeneration operation. As a result, energy consumption efficiency can be further improved.

[0098] (8-4) The refrigerant circuit (R) has one junction flow path (87) connected to both the liquid side end of the first radiator (18A) and the liquid side end of the second radiator (18B). The junction flow path (87) is provided with an expansion valve (82) as a pressure reducing mechanism.

[0099] In this configuration, the refrigerant can be decompressed by providing only one expansion valve (82) in the combined flow path (87), which reduces the number of expansion valves (82) compared to a configuration in which an expansion valve is provided in each of the first high-pressure flow path (85a) and the second high-pressure flow path (85b), thereby simplifying the configuration of the refrigerant circuit (R).

[0100] (8-5) The refrigerant circuit (R) has an auxiliary radiator (73) that heats water to generate water vapor. The carbon dioxide recovery system (1) further includes a supply path (71) for supplying the water vapor generated in the auxiliary radiator (73) to the first space (S1) and the second space (S2) of the first casing (11A). The controller (C) controls the first introduction valve (74a) and the second introduction valve (74b) serving as a supply switching mechanism so that, in a first operation, the water vapor generated in the auxiliary radiator (73) is supplied to the first space (S1), and so that, in a second operation, the water vapor generated in the auxiliary radiator (73) is supplied to the second space (S2).

[0101] In this configuration, water vapor can be supplied to the adsorption members (15A, 15B) during the regeneration operation, thereby improving the efficiency of regeneration of the adsorption members (15A, 15B).

[0102] In addition, the refrigerant circuit (R) is used not only as a heat source for regenerating the adsorption members (15A, 15B) but also as a heat source for generating water vapor, thereby simplifying the carbon dioxide recovery system (1).

[0103] (9) Modifications The above embodiment may have the following modified configurations: In the following explanation, differences from the above embodiment will be mainly described.

[0104] (9-1) Modification 1 As described above, the number of adsorption units (U1, U2) is not limited to two and may be three or more. The carbon dioxide capture system (1) of Modification 1 shown in FIG. 7 includes a third adsorption unit (U3). The third adsorption unit (U3) includes a third casing (11C) that defines a third space (S3), and a third adsorption member (15C) and a third radiator (18C) that are disposed in the third space (S3). The third casing (11C) includes a third inlet (I3) and a third outlet (O3). The air flow path (20) includes a third inlet branch duct (22C) and a third outlet branch duct (23C). The air flow path switching mechanism (30) includes a third inlet damper (37) that opens and closes the third inlet (I3) and a third outlet damper (38) that opens and closes the third outlet (O3). The recovery flow path (61) has a third suction path (61d). The recovery switching mechanism (64) has a third recovery valve (64c). The supply path (71) has a third introduction path (71d). The third introduction path (71d) is provided with a third introduction valve (74c).

[0105] 8, the refrigerant circuit (R) has a third high-pressure flow path (85c). The refrigerant flow path switching mechanism (90) has a third on-off valve (90c) provided in the third high-pressure flow path (85c).

[0106] As shown in FIG. 9 , the carbon dioxide capture system (1) sequentially repeats a first operation, a second operation, and a third operation. The first operation is an operation in which the first adsorption unit (U1) performs a regeneration operation while the second adsorption unit (U2) and the third adsorption unit (U3) simultaneously perform an adsorption operation. The second operation is an operation in which the first adsorption unit (U1) and the third adsorption unit (U3) simultaneously perform a regeneration operation while the second adsorption unit (U2) simultaneously performs an adsorption operation. The third operation is an operation in which the first adsorption unit (U1) and the second adsorption unit (U2) simultaneously perform an adsorption operation while the third adsorption unit (U3) simultaneously performs a regeneration operation. The first operation is an example of a first operation, and the second operation is an example of a second operation.

[0107] The first suction unit (U1), the second suction unit (U2), and the third suction unit (U3) alternately perform regeneration and suction operations, and the execution time T1 of the regeneration operation performed by each suction unit (U1, U2) is shorter than the execution time T2 of the suction operation performed by each suction unit (U1, U2, U3).

[0108] In the first operation, the controller (C) controls the refrigerant flow path switching mechanism (90), the air flow path switching mechanism (30), and the recovery switching mechanism (64) so ​​that the first radiator (18A) heats the first adsorption member (15A), the air in the air flow path (20) flows through the second space (S2) and the third space (S3), and the carbon dioxide desorbed from the first adsorption member (15A) is sent to the recovery tank (63) via the recovery flow path (61). Specifically, in the first operation, the controller (C) closes the first inlet damper (31) and the first outlet damper (32), opens the second inlet damper (33), the second outlet damper (34), the third inlet damper (37), and the third outlet damper (38), opens the first recovery valve (64a), closes the second recovery valve (64b) and the third recovery valve (64c), opens the first introduction valve (74a), closes the second introduction valve (74b) and the third introduction valve (74c), opens the first opening / closing valve (90a), closes the second opening / closing valve (90b) and the third opening / closing valve (90c), and opens the auxiliary opening / closing valve (91).

[0109] In the second operation, the controller (C) controls the refrigerant flow path switching mechanism (90), the air flow path switching mechanism (30), and the recovery switching mechanism (64) so ​​that the second radiator (18B) heats the second adsorption member (15B), the air in the air flow path (20) flows through the first space (S1) and the third space (S3), and the carbon dioxide desorbed from the second adsorption member (15B) is sent to the recovery tank (63) via the recovery flow path (61). Specifically, in the second operation, the controller (C) closes the second inlet damper (33) and the second outlet damper (34), opens the first inlet damper (31), the first outlet damper (32), the third inlet damper (37), and the third outlet damper (38), opens the second recovery valve (64b), closes the first recovery valve (64a) and the third recovery valve (64c), opens the second introduction valve (74b), closes the first introduction valve (74a) and the third introduction valve (74c), opens the second opening / closing valve (90b), closes the first opening / closing valve (90a) and the third opening / closing valve (90c), and opens the auxiliary opening / closing valve (91).

[0110] In the third operation, the controller (C) controls the refrigerant flow path switching mechanism (90), the air flow path switching mechanism (30), and the recovery switching mechanism (64) so ​​that the third radiator (18C) heats the third adsorption member (15C), the air in the air flow path (20) flows through the first space (S1) and the second space (S2), and the carbon dioxide desorbed from the third adsorption member (15C) is sent to the recovery tank (63) via the recovery flow path (61). Specifically, in the third operation, the controller (C) closes the third inlet side damper (37) and the third outlet side damper (38), opens the first inlet side damper (31), the first outlet side damper (32), the second inlet side damper (33), and the second outlet side damper (34), opens the third recovery valve (64c), closes the first recovery valve (64a) and the second recovery valve (64b), opens the third introduction valve (74c), closes the first introduction valve (74a) and the second introduction valve (74b), opens the third opening / closing valve (90c), closes the first opening / closing valve (90a) and the second opening / closing valve (90b), and opens the auxiliary opening / closing valve (91).

[0111] The specific air flow and refrigerant flow are the same as those in the above-described embodiment, and therefore will not be described here. Similarly, the number of adsorption units (U1, U2) may be four, or may be five or more.

[0112] (9-2) Modification 2 In Modification 2 shown in Fig. 10, the evaporator (36) of the refrigerant circuit (R) is arranged in the suction duct (21), which is an upstream flow path. A temperature sensor (51) and a humidity sensor (52) are arranged in the suction duct (21). The temperature sensor (51) detects the temperature of air flowing in the suction duct (21) upstream of the evaporator (36). The humidity sensor (52) detects the humidity (strictly speaking, relative humidity) of the air flowing in the suction duct (21) upstream of the evaporator (36).

[0113] In the second modification, in the first operation, the air cooled by the evaporator (36) passes through the second adsorption member (15B) in the second space (S2). This reduces the temperature of the second adsorption member (15B), improving the adsorption efficiency of the second adsorption member (15B). In addition, heat of the outdoor air is recovered by the refrigerant through the evaporator (36). This heat can therefore be used to regenerate the first adsorption member (15A).

[0114] In the second modification, in the second operation, the air cooled by the evaporator (36) passes through the first adsorption member (15A) in the first space (S1). This reduces the temperature of the first adsorption member (15A), improving the adsorption efficiency of the first adsorption member (15A). In addition, heat of the outdoor air is recovered by the refrigerant through the evaporator (36). This heat can therefore be used to regenerate the second adsorption member (15B).

[0115] In the second modification, the controller (C) controls the rotation speed of the compressor (81) so that the evaporator (36) cools the air flowing through the intake duct (21) to a temperature equal to or lower than the dew point temperature. Specifically, the controller (C) determines the dew point temperature of the air flowing through the intake duct (21) based on the temperature detected by the temperature sensor (51) and the humidity detected by the humidity sensor (52), and then determines a target evaporation pressure of the evaporator (36) at which the air temperature becomes equal to or lower than the dew point temperature. The controller (C) controls the rotation speed of the compressor (81) so that the evaporation pressure of the evaporator (36) reaches the target evaporation pressure. As a result, moisture in the air condenses, and the air is dehumidified.

[0116] In the first and second operations, the air dehumidified in the evaporator (36) flows through the first adsorption member (15A) and the second adsorption member (15B). As a result, adhesion of moisture in the air to the first adsorption member (15A) and the second adsorption member (15B) can be suppressed, and deterioration of the adsorbent due to the influence of moisture can be suppressed. In particular, when the adsorbent is an amine-based substance, the adsorbent is likely to deteriorate due to the influence of moisture. By dehumidifying the air upstream of the adsorption members (15A, 15B), deterioration of the adsorbent containing the amine-based substance can be effectively suppressed.

[0117] (9-3) Modification 3 In Modification 3, the evaporator (36) includes an inlet evaporator (41) and an outlet evaporator (42). As shown in Fig. 11, the inlet evaporator (41) is disposed in the intake duct (21), and the outlet evaporator (42) is disposed in the exhaust duct (24). An outdoor air temperature sensor (53) for detecting the temperature of outdoor air is provided in the intake duct (21).

[0118] As shown in Fig. 12, the refrigerant circuit (R) of the third modification has a first low-pressure flow path (88a) and a second low-pressure flow path (88b) arranged in parallel with each other. The first low-pressure flow path (88a) is provided with an inlet evaporator (41) and a first low-pressure on-off valve (91a). The first low-pressure on-off valve (91a) is provided upstream of the inlet evaporator (41) in the first low-pressure flow path (88a). The second low-pressure flow path (88b) is provided with an outlet evaporator (42) and a second low-pressure on-off valve (91b). The second low-pressure on-off valve (91b) is provided upstream of the second evaporator (36b) in the second low-pressure flow path (88b).

[0119] In the first operation and the second operation, the controller (C) controls the refrigerant circuit (R) to switch between a first refrigerant operation in which the refrigerant flows through the inlet-side evaporator (41) and a second refrigerant operation in which the refrigerant flows through the outlet-side evaporator (42) based on the outside air temperature detected by the outside air temperature sensor (53).

[0120] Specifically, when the outdoor air temperature is higher than a predetermined value, the controller (C) opens the first low-pressure on-off valve (91a) and closes the second low-pressure on-off valve (91b). As a result, the refrigerant circuit (R) performs a first refrigerant operation in which the refrigerant flows through the inlet evaporator (41) and the outlet evaporator (42) is stopped. When the outdoor air temperature is relatively high, the temperature difference between the refrigerant and the air in the inlet evaporator (41) increases. This increases the amount of heat absorbed by the refrigerant from the outdoor air in the inlet evaporator (41), thereby improving the COP of the refrigeration cycle apparatus (80). This also increases the cooling and dehumidifying effects of the air in the intake duct (21).

[0121] When the outdoor air temperature is lower than a predetermined value, the controller (C) closes the second low-pressure on-off valve (91b) and opens the first low-pressure on-off valve (91a). As a result, the refrigerant circuit (R) performs a second refrigerant operation in which the refrigerant flows through the outlet evaporator (42) and the inlet evaporator (41) is stopped. When the outdoor air temperature is relatively low, the temperature difference between the refrigerant and the air in the inlet evaporator (41) becomes small. In this case, the inlet evaporator (41) cannot sufficiently recover heat from the outdoor air, and the cooling and dehumidifying effects of the air are not sufficient. In the third modification, under such conditions, the refrigerant flows through the outlet evaporator (42). This allows the residual heat of the air used to regenerate the first adsorption member (15A) and the second adsorption member (15B) to be recovered to the refrigerant circuit (R). This improves the COP of the refrigeration cycle apparatus (80).

[0122] (9-4) Modification 4 In Modification 4 shown in FIG. 13 , the recovery unit (60) is provided with an auxiliary evaporator (75) and a water container (76) as a water recovery section. The auxiliary evaporator (75) is provided in parallel with the evaporator (36), for example, in the refrigerant circuit (R). The water container (76) is connected to the main flow path (61c) of the recovery flow path (61). The carbon dioxide-containing gas flowing through the recovery flow path (61) passes through the water container (76). The auxiliary evaporator (75) is disposed inside the water container (76).

[0123] The auxiliary evaporator (75) condenses water contained in the gas by cooling the gas flowing in the water container (76). The condensed water is collected in the water container (76) and discharged into the water container (76) through, for example, a drainage channel.

[0124] The controller (C) may control the rotation speed of the compressor (81) so as to condense water from the gas, as in Modification 2. The refrigerant circuit (R) may also be provided with a pressure control valve for adjusting the evaporation pressure of the auxiliary evaporator (75). The water recovery unit may be a tray for receiving water condensed in the auxiliary evaporator (75).

[0125] (9-5) Modification 5 A carbon dioxide capture system (1) of Modification 5 shown in FIGS. 14 and 15 differs from the above embodiment in the configurations of the first adsorption unit (U1), the second adsorption unit (U2), and the refrigerant circuit (R).

[0126] (9-5-1) Configuration of Carbon Dioxide Capture System As shown in FIG. 14 , the first adsorption unit (U1) has a first casing (11A). The first casing (11A) has a first inlet-side partition plate (16A) and a first outlet-side partition plate (17A). The first inlet-side partition plate (16A) is located upstream of the air flow path (20) of the first casing (11A), and the first outlet-side partition plate (17A) is located downstream of the air flow path (20) of the first casing (11A). Inside the first casing (11A), a first space (S1) is formed between the first inlet-side partition plate (16A) and the first outlet-side partition plate (17A). A first inlet (I1) is formed in the first inlet-side partition plate (16A), and a first outlet (O1) is formed in the first outlet-side partition plate (17A).

[0127] The first casing (11A) is formed with a first inlet flow path (26A) and a first outlet flow path (27A). The first inlet flow path (26A) and the first outlet flow path (27A) form a first flow path that can communicate with the first space (S1). A first fan (35A) is disposed in the first inlet flow path (26A). The first fan (35A) may be disposed in the first outlet flow path (27A). In the fifth modification, a first evaporator (36A) is disposed in the first outlet flow path (27A).

[0128] The second adsorption unit (U2) has a second casing (11B). The second casing (11B) has a second inlet-side partition (16B) and a second outlet-side partition (17B). The second inlet-side partition (16B) is located upstream of the air flow path (20) of the second casing (11B), and the second outlet-side partition (17B) is located downstream of the air flow path (20) of the second casing (11B). A second space (S2) is formed inside the second casing (11B) between the second inlet-side partition (16B) and the second outlet-side partition (17B). A second inlet (I2) is formed in the second inlet-side partition (16B), and a second outlet (O2) is formed in the second outlet-side partition (17B).

[0129] The second casing (11B) is formed with a second inlet flow path (26B) and a second outlet flow path (27B). The second inlet flow path (26B) and the second outlet flow path (27B) form a second flow path that can communicate with the second space (S2). A second fan (35B) is disposed in the second inlet flow path (26B). The second fan (35B) may be disposed in the second outlet flow path (27B). In the fifth modification, a second evaporator (36B) is disposed in the second outlet flow path (27B).

[0130] The air flow path switching mechanism (30) of the fifth modified example is the same as that of the embodiment. A first inlet (I1) is provided at the first inlet (I1), a first outlet (O1) is provided at the first outlet damper (32), a second inlet (I2) is provided at the second inlet (I2), and a second outlet damper (34) is provided at the second outlet (O2).

[0131] As shown in Fig. 15 , the refrigerant circuit (R) of the fifth modification includes a first evaporator (36A) and a second evaporator (36B). The first evaporator (36A) and the second evaporator (36B) are arranged in parallel in the refrigerant circuit (R). Specifically, a first low-pressure flow path (88a) and a second low-pressure flow path (88b) are arranged in parallel on the suction side of the compressor (81) in the refrigerant circuit (R). The first evaporator (36A) is arranged in the first low-pressure flow path (88a), and the second evaporator (36B) is arranged in the second low-pressure flow path (88b).

[0132] The refrigerant flow path switching mechanism (90) of the fifth modification includes a first low-pressure-side valve (93a) and a second low-pressure-side valve (93b). The first low-pressure-side valve (93a) is provided in the first low-pressure flow path (88a), and the second low-pressure-side valve (93b) is provided in the second low-pressure flow path (88b). In this example, the first low-pressure-side valve (93a) and the second low-pressure-side valve (93b) are solenoid on-off valves. The first low-pressure-side valve (93a) and the second low-pressure-side valve (93b) may be electronic expansion valves or flow control valves whose opening degrees are adjustable.

[0133] In the fifth modification, when the refrigerant flow path switching mechanism (90) is in the first state, the first on-off valve (90a) is in the open state, the second on-off valve (90b) is in the closed state, the first low-pressure side valve (93a) is in the closed state, and the second low-pressure side valve (93b) is in the open state. When the refrigerant flow path switching mechanism (90) is in the second state, the second on-off valve (90b) is in the open state, the first on-off valve (90a) is in the closed state, the second low-pressure side valve (93b) is in the closed state, and the first low-pressure side valve (93a) is in the open state.

[0134] (9-5-2) Operation The carbon dioxide capture system (1) alternately performs the first operation and the second operation. In the fifth modification, the control of the first evaporator (36A) and the second evaporator (36B) is different from that in the embodiment.

[0135] In the first operation, the controller (C) stops the first fan (35A) and operates the second fan (35B). In the first operation, the controller (C) controls the refrigerant flow path switching mechanism (90), the air flow path switching mechanism (30), and the recovery switching mechanism (64) so ​​that the first radiator (18A) heats the first adsorption member (15A), the target air in the air flow path (20) flows through the second inlet-side flow path (26B) and the second space (S2), and carbon dioxide desorbed from the first adsorption member (15A) is sent to the recovery tank (63) via the recovery flow path (61). Specifically, in the first operation, the controller (C) sets the refrigerant flow path switching mechanism (90) to a first state, the air flow path switching mechanism (30) to a fourth state, and the recovery switching mechanism (64) to a fifth state. More specifically, in the first operation, the controller (C) closes the first inlet damper (31) and the first outlet damper (32), opens the second inlet damper (33) and the second outlet damper (34), opens the first recovery valve (64a), closes the second recovery valve (64b), opens the first introduction valve (74a), closes the second introduction valve (74b), opens the first opening / closing valve (90a), closes the second opening / closing valve (90b), opens the auxiliary opening / closing valve (91), closes the first low-pressure side valve (93a), and opens the second low-pressure side valve (93b).

[0136] In the refrigerant circuit (R) shown in FIG. 15 , refrigerant compressed by the compressor (81) is divided into a first high-pressure flow path (85a) and an auxiliary high-pressure flow path (86). The refrigerant in the first high-pressure flow path (85a) dissipates heat to the air in the first space (S1) while flowing through the first heat radiator (18A). The refrigerant in the auxiliary high-pressure flow path (86) dissipates heat to the surrounding water while flowing through the auxiliary heat radiator (73). The refrigerant that has passed through the first high-pressure flow path (85a) and the auxiliary high-pressure flow path (86) merges in a junction flow path (87) and is then decompressed by the expansion valve (82). The decompressed refrigerant flows through the second low-pressure flow path (88b) and passes through the second evaporator (36B). The refrigerant in the second evaporator (36B) absorbs heat from the surrounding air and evaporates. The refrigerant evaporated in the second evaporator (36B) is sucked into the compressor (81) and compressed again.

[0137] In the first operation, outdoor air from the outdoor space passes through the second inlet flow path (26B) and the second inlet (I2) and enters the second space (S2). In the second space (S2), carbon dioxide in the air is adsorbed by the second adsorbent (15B). The air that has passed through the second adsorbent (15B) passes through the second outlet (O2) and flows through the second outlet flow path (27B). In the second evaporator (36B) of the second outlet flow path (27B), heat is exchanged between the air and the refrigerant, and heat of the air is recovered as heat of evaporation of the refrigerant. The air in the second outlet flow path (27B) is discharged to the outdoor space. In the first operation, the first radiator (18A) heats the first adsorbent (15A). As a result, carbon dioxide is desorbed from the first adsorbent (15A).

[0138] In the second operation, the controller (C) stops the second fan (35B) and operates the first fan (35A). In the second operation, the controller (C) controls the refrigerant flow path switching mechanism (90), the air flow path switching mechanism (30), and the recovery switching mechanism (64) so ​​that the second radiator (18B) heats the second adsorption member (15B), the target air in the air flow path (20) flows through the first inlet-side flow path (26A) and the first space (S1), and carbon dioxide desorbed from the second adsorption member (15B) is sent to the recovery tank (63) through the recovery flow path (61). Specifically, in the second operation, the controller (C) sets the refrigerant flow path switching mechanism (90) to the second state, the air flow path switching mechanism (30) to the third state, and the recovery switching mechanism (64) to the sixth state. More specifically, in the second operation, the controller (C) closes the second inlet damper (33) and the second outlet damper (34), opens the first inlet damper (31) and the first outlet damper (32), opens the second recovery valve (64b), closes the first recovery valve (64a), opens the second introduction valve (74b), closes the first introduction valve (74a), opens the second opening / closing valve (90b), opens the first opening / closing valve (90a), closes the auxiliary opening / closing valve (91), closes the second low-pressure side valve (93b), and opens the first low-pressure side valve (93a).

[0139] In the refrigerant circuit (R) shown in FIG. 15 , refrigerant compressed in the compressor (81) is divided into a second high-pressure flow path (85b) and an auxiliary high-pressure flow path (86). The refrigerant in the second high-pressure flow path (85b) dissipates heat to the air in the second space (S2) while flowing through the second heat radiator (18B). The refrigerant in the auxiliary high-pressure flow path (86) dissipates heat to the surrounding water while flowing through the auxiliary heat radiator (73). The refrigerant that has passed through the second high-pressure flow path (85b) and the auxiliary high-pressure flow path (86) merges in a junction flow path (87) and is then decompressed by the expansion valve (82). The decompressed refrigerant flows through the first low-pressure flow path (88a) and passes through the first evaporator (36A). The refrigerant in the first evaporator (36A) absorbs heat from the surrounding air and evaporates. The refrigerant evaporated in the first evaporator (36A) is sucked into the compressor (81) and compressed again.

[0140] In the second operation, outdoor air from the outdoor space passes through the first inlet flow path (26A) and the first inlet (I1) and enters the first space (S1). In the first space (S1), carbon dioxide in the air is adsorbed by the first adsorption member (15A). The air that has passed through the first adsorption member (15A) passes through the first outlet (O1) and flows through the first outlet flow path (27A). In the first evaporator (36A) of the first outlet flow path (27A), heat is exchanged between the air and the refrigerant, and heat of the air is recovered as heat of evaporation of the refrigerant. The air in the first outlet flow path (27A) is discharged to the outdoor space. In the second operation, the second radiator (18B) heats the second adsorption member (15B). As a result, carbon dioxide is desorbed from the second adsorption member (15B).

[0141] In the fifth modification, at the start of the second operation, the relatively high-temperature air in the first space (S1), which was on the regeneration side, passes through the first evaporator (36A). Therefore, the first evaporator (36A) can recover the heat used to regenerate the first adsorption member (15A). In the fifth modification, at the start of the first operation, the relatively high-temperature air in the second space (S2), which was on the regeneration side, passes through the second evaporator (36B). Therefore, the second evaporator (36B) can recover the heat used to regenerate the second adsorption member (15B).

[0142] (9-6) Modification 6 Modification 6 differs from Modification 5 in the arrangement of the first evaporator (36A) and the second evaporator (36B). As shown in Fig. 16 , the first evaporator (36A) is arranged in the first inlet flow path (26A) upstream of the first space (S1), and the second evaporator (36B) is arranged in the second inlet flow path (26B) upstream of the second space (S2). Other than that, the configuration of Modification 6 is the same as that of Modification 5.

[0143] In the sixth modification, in the first operation, outdoor air passes through the second evaporator (36B) of the second inlet flow path (26B). The air cooled by the second evaporator (36B) passes through the second adsorption member (15B) in the second space (S2). This reduces the temperature of the second adsorption member (15B), improving the adsorption efficiency of the second adsorption member (15B). In addition, heat from the outdoor air is recovered by the refrigerant through the second evaporator (36B). This heat can therefore be used to regenerate the first adsorption member (15A).

[0144] In the sixth modification, in the second operation, outdoor air passes through the first evaporator (36A) of the first inlet flow path (26A). The air cooled by the first evaporator (36A) passes through the first adsorption member (15A) in the first space (S1). This reduces the temperature of the first adsorption member (15A), improving the adsorption efficiency of the first adsorption member (15A). In addition, heat from the outdoor air is recovered by the refrigerant via the first evaporator (36A). This heat can therefore be used to regenerate the second adsorption member (15B).

[0145] In the sixth modification, similarly to the second modification, the controller (C) may control the rotation speed of the compressor (81) so that the first evaporator (36A) or the second evaporator (36B) cools the air to a temperature equal to or lower than the dew point temperature, thereby dehumidifying the air before it flows through the adsorption members (15A, 15B).

[0146] The number of adsorption units (U) in Modifications 5 and 6 is merely an example. The carbon dioxide capture system (1) may have three or more adsorption units (U). In Modifications 5 and 6, one inlet flow path may be provided connecting the inlet end of the first inlet flow path (26A) and the inlet end of the second inlet flow path (26B), and one fan may be disposed in the inlet flow path. One outlet flow path may be provided connecting the outlet end of the first outlet flow path (27A) and the outlet end of the second outlet flow path (27B), and one fan may be disposed in the outlet flow path. The refrigerant circuits (R) of Modifications 5 and 6 may be applied to the carbon dioxide capture system (1) of the above-described embodiment shown in FIG. 1. In this case, the first evaporator (36) of Modification 5 may be disposed in the first outlet branch duct (23A), which is the first flow path, and the second evaporator (36B) of Modification 5 may be disposed in the second outlet branch duct (23B), which is the second flow path. The first evaporator (36) of variant 6 may be arranged in the first inlet branch duct (22A), which is the first flow path, and the second evaporator (36B) of variant 6 may be arranged in the second inlet branch duct (22B), which is the second flow path.

[0147] (10) Other Embodiments In the above-described embodiment and each modification, the following configuration may be adopted.

[0148] The carbon dioxide capture system (1) does not have to be a DAC system that directly captures carbon dioxide from the atmosphere. For example, the carbon dioxide capture system (1) may capture carbon dioxide from a mixture of air and industrial exhaust gases.

[0149] The pressure reducing mechanism does not have to be the expansion valve (82) and may be a capillary tube or an expander that recovers the power of the refrigerant. The expansion valve (82) may be a temperature sensitive expansion valve.

[0150] The adsorbing member (50) may adsorb carbon dioxide in the room air instead of the outdoor air. The adsorbing member (50) may be applied to, for example, a ventilation system for ventilating a room.

[0151] The first storage section and the second storage section do not necessarily have to be casings made of a single member, but may be configured so that the first space (S1) and the second space (S2) are formed by integrally connecting multiple members.

[0152] The air flow path switching mechanism (30) may be something other than a damper, and may be a slide shutter or a valve such as a ball valve that switches the air flow.

[0153] The refrigerant channel switching mechanism (90) does not have to be an on-off valve, but may be a three-way valve or a four-way valve.

[0154] The recovery switching mechanism (64) does not have to be an on-off valve, but may be a three-way valve, a four-way valve, or a rotary valve.

[0155] The supply switching mechanism does not have to be an on-off valve, but may be a three-way valve, a four-way valve, or a rotary valve.

[0156] The capture section that captures carbon dioxide does not have to be a capture tank, and may be, for example, an adsorption section that adsorbs the captured carbon dioxide. The carbon dioxide capture system (1) does not necessarily have to have a capture section. The capture unit (60) may introduce the captured carbon dioxide underground. In other words, the capture section that captures carbon dioxide may be soil.

[0157] The recovery unit (60) may include a first recovery flow path communicating with the first space, a second recovery flow path communicating with the second space, a first pump provided in the first recovery flow path, and a second pump provided in the second recovery flow path. In this configuration, the controller (C) operates the first pump (62) and stops the second pump (62) in the first operation. This allows carbon dioxide desorbed from the first adsorption member (15A) to be sent to the recovery tank (63) through the first recovery flow path. The controller (C) operates the second pump (62) and stops the first pump (62) in the second operation. This allows carbon dioxide desorbed from the second adsorption member (15B) to be sent to the recovery tank (63) through the second recovery flow path.

[0158] The carbon dioxide capture system (1) does not need to have a fan in the air flow path (20). In this case, air conveyed from another device, such as factory exhaust gas, may be introduced into the air flow path (20).

[0159] Although the embodiments and modifications have been described above, it will be understood that various modifications in form and details are possible without departing from the spirit and scope of the claims. Furthermore, the above embodiments, modifications, and other embodiments may be combined or substituted as appropriate as long as the functionality of the subject matter of the present disclosure is not impaired.

[0160] The above-mentioned descriptions such as "first," "second," "third," etc. are used to distinguish the words to which these descriptions are attached, and do not limit the number or order of the words.

[0161] As described above, the present disclosure is useful for carbon dioxide capture systems.

[0162] 1 Carbon dioxide recovery system 11A First casing (first storage section) 11B Second casing (second storage section) 15A First adsorption member 15B Second adsorption member 18A First radiator 18B Second radiator 21 Intake duct (upstream flow path) 22A First inlet branch duct (first flow path) 22B Second inlet branch duct (second flow path) 23A First outlet branch duct (first flow path) 23B Second outlet branch duct (second flow path) 24 Exhaust duct (downstream flow path) 26A First inlet flow path (first flow path) 26B Second inlet flow path (second flow path) 27A First outlet flow path (first flow path) 27B Second outlet flow path (second flow path) 30 Air flow path switching mechanism 36 Evaporator 60 Recovery unit 61 Recovery flow path 63 Recovery tank (recovery section) 64 Recovery switching mechanism 71 Supply path 73 Auxiliary radiator 75 Auxiliary evaporator 81 Compressor 82 Expansion valve (pressure reducing mechanism) 87 Junction path 90 Refrigerant flow path switching mechanism C Controller (control section) R Refrigerant circuit S1 First space S2 Second space

Claims

1. A refrigerant circuit (R) having a first adsorption member (15A) and a second adsorption member (15B) that adsorb carbon dioxide in target air, a compressor (81), a first radiator (18A) and a second radiator (18B) arranged in parallel with each other, a pressure reducing mechanism (82), an evaporator (36, 36A, 36B), and a refrigerant flow path switching mechanism (90) that switches the flow of refrigerant in the first radiator (18A) and the second radiator (18B), and performing a refrigeration cycle, a first storage section (11A) that forms a first space (S1) in which the first adsorption member (15A) and the first radiator (18A) are arranged, and a second storage section (11B) that forms a second space (S2) in which the second adsorption member (15B) and the second radiator (18B) are arranged, a carbon dioxide capture system comprising: an air flow path switching mechanism (30) that switches the air flow between the first space (S1) and the second space (S2); and a capture unit (60) that selectively captures carbon dioxide desorbed from the first adsorption member (15A) and the second adsorption member (15B).

2. The recovery unit (60) includes a recovery flow path (61) for sending carbon dioxide desorbed from the first adsorption member (15A) and the second adsorption member (15B) to a predetermined recovery section (63), and a recovery switching mechanism (64) for switching the flow of carbon dioxide in the recovery flow path (61), 2. The carbon dioxide capture system according to claim 1, further comprising a control unit (C) that controls the refrigerant flow path switching mechanism (90), the air flow path switching mechanism (30), and the capture switching mechanism (64) to perform a first operation in which the first radiator (18A) heats the first adsorption member (15A), the target air flows through the second space (S2), and the carbon dioxide desorbed from the first adsorption member (15A) is sent to the capture section (63) through the recovery flow path (61), and a second operation in which the second radiator (18B) heats the second adsorption member (15B), the target air flows through the first space (S1), and the carbon dioxide desorbed from the second adsorption member (15B) is sent to the capture section (63) through the recovery flow path (61).

3. The refrigerant flow path switching mechanism (90) is configured to switch between a first state in which the refrigerant flows through the first radiator (18A) and a second state in which the refrigerant flows through the second radiator (18B); the air flow path switching mechanism (30) is configured to switch between a third state in which a target space containing the target air communicates with the first space (S1) and the target space is isolated from the second space (S2), and a fourth state in which the target space communicates with the second space (S2) and the target space is isolated from the first space (S1); the recovery switching mechanism (64) is configured to switch between a fifth state in which the first space (S1) communicates with the recovery section (63) and a sixth state in which the second space (S2) communicates with the recovery section (63); and the control unit (C) 3. The carbon dioxide capture system according to claim 2, wherein in the first operation, the refrigerant flow path switching mechanism (90) is in a first state, the air flow path switching mechanism (30) is in a fourth state, and the capture switching mechanism (64) is in the fifth state; and in the second operation, the refrigerant flow path switching mechanism (90) is in a second state, the air flow path switching mechanism (30) is in a third state, and the capture switching mechanism (64) is in the sixth state.

4. The carbon dioxide capture system according to any one of claims 1 to 3, further comprising a downstream flow path (24) located downstream of the first storage portion (11A) and the second storage portion (11B), and the evaporator (36) is disposed in the downstream flow path (24).

5. The carbon dioxide capture system according to any one of claims 1 to 3, further comprising an upstream flow path (21) located upstream of the first storage section (11A) and the second storage section (11B), and the evaporator (36) is disposed in the upstream flow path (21).

6. The carbon dioxide capture system according to claim 5, further comprising a control unit (C) that controls the rotation speed of the compressor (81) so that the evaporator (36) cools the air to a temperature equal to or lower than the dew point temperature.

7. A carbon dioxide capture system according to any one of claims 1 to 6, wherein the refrigerant circuit (R) has a single junction flow path (87) connected to both a liquid side end of the first radiator (18A) and a liquid side end of the second radiator (18B), and the pressure reduction mechanism (82) is provided in the junction flow path (87).

8. The carbon dioxide capture system according to any one of claims 1 to 7, wherein the refrigerant circuit (R) has an auxiliary radiator (73) that heats water to generate steam, and further includes a supply path (71) for supplying the steam generated in the auxiliary radiator (73) to the inside of the first space (S1) and the second space (S2).

9. A carbon dioxide recovery system according to any one of claims 2 to 8, wherein the refrigerant circuit (R) has an auxiliary evaporator (75) arranged in the recovery flow path (61).

10. The carbon dioxide capture system according to claim 1, further comprising: a first flow path (22A, 23A, 26A, 27A) capable of communicating with the first space (S1) of the first storage portion (11A); and a second flow path (22B, 23B, 26B, 27B) capable of communicating with the second space (S2) of the second storage portion (11B), wherein the refrigerant circuit (R) has, as the evaporators, a first evaporator (36A) and a second evaporator (36B) arranged in parallel with each other, the first evaporator (36A) being arranged in the first flow path (22A, 23A, 26A, 27A), and the second evaporator (36B) being arranged in the second flow path (22B, 23B, 26B, 27B).

11. The recovery unit (60) includes a recovery flow path (61) for sending carbon dioxide desorbed from the first adsorption member (15A) and the second adsorption member (15B) to a predetermined recovery section (63), and a recovery switching mechanism (64) for switching the flow of carbon dioxide in the recovery flow path (61), The system further includes a control unit (C) that controls the refrigerant flow path switching mechanism (90), the air flow path switching mechanism (30), and the recovery switching mechanism (64) to perform a first operation in which the first radiator (18A) heats the first adsorption member (15A), the target air flows through the second space (S2) and the second evaporator (36B) of the second flow paths (22B, 23B, 26B, 27B), and carbon dioxide desorbed from the first adsorption member (15A) is sent to a recovery section (63) through the recovery flow path (61), and a second operation in which the second radiator (18B) heats the second adsorption member (15B), the target air flows through the first space (S1) and the first evaporator (36A) of the first flow paths (22A, 23A, 26A, 27A), and carbon dioxide desorbed from the second adsorption member (15B) is sent to a recovery section (63) through the recovery flow path (61). The carbon dioxide capture system of claim 10.

12. The refrigerant flow path switching mechanism (90) is configured to switch between a first state in which the refrigerant flows through the first radiator (18A) and the second evaporator (36B) and a second state in which the refrigerant flows through the second radiator (18B) and the first evaporator (36A); the air flow path switching mechanism (30) is configured to switch between a third state in which the first space (S1) communicates with a target space containing the target air and the first flow path (22A, 23A, 26A, 27A) and the second space (S2) is blocked from the target space and the first second flow path (22B, 23B, 26B, 27B) and a fourth state in which the second space (S2) communicates with the target space and the first flow path (22A, 23A, 26A, 27A) and the first space (S1) is blocked from the target space and the first flow path (22A, 23A, 26A, 27A); the recovery switching mechanism (64) is configured to switch between a fifth state in which the first space (S1) communicates with the recovery section (63) side and a sixth state in which the second space (S2) communicates with the recovery section (63) side; 12. The carbon dioxide capture system according to claim 11, wherein the control unit (C): in the first operation, sets the refrigerant flow path switching mechanism (90) in a first state, sets the air flow path switching mechanism (30) in a fourth state, and sets the capture switching mechanism (64) in the fifth state; and in the second operation, sets the refrigerant flow path switching mechanism (90) in a second state, sets the air flow path switching mechanism (30) in a third state, and sets the capture switching mechanism (64) in the sixth state.

13. A carbon dioxide capture system according to any one of claims 10 to 12, wherein the first flow path (23A, 27A) is located downstream of the first space (S1), and the first flow path (23B, 27B) is located downstream of the second space (S2).

14. A carbon dioxide capture system according to any one of claims 10 to 12, wherein the first flow path (22A, 26A) is located upstream of the first space (S1), and the second flow path (22B, 26B) is located upstream of the second space (S2).

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