Co2 separation system

Abstract

To provide a CO2 separation system that quickly reduces CO2 concentration in a target space while performing CO2 separation.SOLUTION: A CO2 separation system 1 is a CO2 separation system comprising a CO2 separation part for separating CO2 from circulating air. The system has a first state of circulating air in a target space in an indoor space to the CO2 separation part and sending air with reduced CO2 concentration into the target space, and a second state of ventilating the target space, and comprises a control unit 5 that controls the first state and the second state. The CO2 separation part operates so as to increase CO2 separation capacity with an increase in CO2 concentration of air in the target space. The control unit 5 performs operation in the first state until the CO2 separation capacity in the CO2 separation part reaches a reference value, and performs operation by combining the first state and the second state when the CO2 separation capacity exceed the reference value.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a CO2 separation system that separates CO2 from the air in a target space. [Background technology]

[0002] In order to reduce the carbon dioxide (CO2) concentration in the air of a closed space unit, the air of the space unit is supplied to a purge gas membrane system. In the purge gas membrane system, CO2 preferentially passes through the membrane module, leaving CO2-reduced air. The remaining air is returned to the space unit (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2006-512946 Summary of the Invention [Problem to be solved by the invention]

[0004] A CO2 separation system has a module that separates CO2 from the air in the target space and returns it to the target space, thereby reducing the carbon dioxide (CO2) concentration in the air in the closed target space.However, with such CO2 separation systems, the reduction of CO2 concentration depends on the CO2 separation capacity of the module, so there was an issue in that it was difficult to quickly reduce the CO2 concentration if the CO2 concentration in the target space suddenly increased. [Means for solving the problem]

[0005] To solve the above problems, the CO2 separation system of the present invention is a CO2 separation system equipped with a CO2 separation unit that separates CO2 from circulating air. The system has two modes: a first mode in which air from a target indoor space is circulated through the CO2 separation unit and air with a reduced CO2 concentration is blown into the target space; and a second mode in which the target space is ventilated. The system also includes a control unit that controls the first and second modes. The CO2 separation unit operates to increase its CO2 separation capacity as the CO2 concentration of the air in the target space increases. The control unit operates in the first mode until the CO2 separation capacity of the CO2 separation unit reaches a reference value, and when the reference value is exceeded, operates in a combination of the first and second modes. This achieves the intended purpose. [Effects of the Invention]

[0006] According to the CO2 separation system of the present invention, the CO2 concentration in the target space can be quickly reduced while suppressing heat loss. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram of a CO2 separation system according to the first embodiment. [Figure 2] FIG. 2 is a diagram showing an outline of the CO2 separation element of FIG. [Figure 3] FIG. 3 is a diagram showing an air flow in the first state in the first embodiment. [Figure 4] FIG. 4 is a diagram showing an air flow in the second state in the first embodiment. [Figure 5] FIG. 5 is a schematic diagram of a CO2 separation system according to the second embodiment. [Figure 6] FIG. 6 is a diagram showing the air flow in the first state in the second embodiment. [Figure 7] FIG. 7 is a diagram showing the air flow in the second state in the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments are merely examples of the present invention and do not limit the technical scope of the present invention. Furthermore, the drawings described in the embodiments are schematic drawings, and the ratios of the sizes and thicknesses of the components in the drawings do not necessarily reflect the actual dimensional ratios.

[0009] (Embodiment 1) A CO2 separation system 1 according to this embodiment will be described with reference to Fig. 1. Fig. 1 is a schematic diagram of a CO2 separation system according to the first embodiment.

[0010] As shown in FIG. 1, a CO2 separation system 1 is installed indoors in a building 2 such as a house. The CO2 separation system 1 is a device that removes a target gas (e.g., CO2) from the air in a target indoor space. The CO2 separation system 1 includes a housing 10, a CO2 separation element 20, an indoor air fan 31, an indoor air filter 37, an outdoor air fan 41, an outdoor air filter 47, a first flow rate adjustment unit 4a, a second flow rate adjustment unit 4b, a third flow rate adjustment unit 4c, and a fourth flow rate adjustment unit 4d, collectively referred to as a flow rate adjustment unit 4, a control unit 5, an indoor air CO2 concentration detection unit 7, and a first backflow suppression unit 8a and a second backflow suppression unit 8b, collectively referred to as a backflow suppression unit 8.

[0011] The housing 10 is the outer frame of the CO2 separation system 1. An inside air port 33, an air supply port 35, an outside air port 43, and an exhaust port 45 are arranged on the outer periphery of the housing 10. An inside air space 23, an air supply space 24, an outside air space 25, and an exhaust space 26 are provided inside the housing 10. Details of each of these spaces will be described later.

[0012] The inside air port 33 is an intake port that draws air from within the target space into the housing 10, and is connected in communication with an indoor intake port 51 provided in the building 2 by an inside air introduction duct 52.

[0013] The indoor air inlet 51 is an opening provided in the target space of the building 2, and is an opening through which air (indoor air) in the target space is introduced into the CO2 separation system 1.

[0014] The inside air introduction duct 52 is a duct that introduces inside air, which is the air of the target space, into the housing 10, and connects the inside air inlet 33 and the indoor air inlet 51. The inside air introduction duct 52 functions as a return air duct. The inside air is introduced into the inside air space 23 of the CO2 separation system 1 through the indoor air inlet 51, the inside air introduction duct 52, and the inside air inlet 33.

[0015] Air intake 35 is a discharge port that discharges air whose CO2 concentration has been reduced by CO2 separation system 1 from housing 10 as intake air. Air intake 35 is connected in communication with indoor air outlet 53 provided in building 2 via indoor air outlet duct 54.

[0016] The indoor air outlet 53 is an opening provided in the building 2, and is an opening that supplies air whose CO2 concentration has been reduced by the CO2 separation system 1 to the target space.

[0017] The inside air outlet duct 54 is a duct that ventilates the air that has circulated inside the housing 10 as supply air into the target space, and connects the air intake port 35 and the indoor outlet 53. The inside air outlet duct 54 functions as an intake air passage. The air whose CO2 concentration has been reduced by the CO2 separation system 1 passes from the air intake space 24 through the air intake port 35, the inside air outlet duct 54, and the indoor outlet 53 and returns to the target space as supply air.

[0018] The outside air port 43 is an intake port that draws outside air, which is outdoor air, into the housing 10. The outside air port 43 is connected in communication with an outdoor intake port 55 provided in the building 2 by an outside air introduction duct 56.

[0019] The outdoor air intake 55 is an opening provided in the building 2, and is used to draw outdoor air into the CO2 separation system. This is the opening introduced into 1.

[0020] The outside air introduction duct 56 is a duct that introduces outside air into the housing 10 and connects the outdoor air inlet 55 and the outside air outlet 43. The outside air introduction duct 56 functions as an outside air passage. Outdoor air passes through the outdoor air inlet 55, the outside air introduction duct 56, and the outside air outlet 43 and is introduced into the outside air space 25 of the CO2 separation system 1.

[0021] The exhaust port 45 is an outlet that discharges air whose CO2 concentration has been increased by the CO2 separation element 20 or air blown from the target space as exhaust air from the housing 10. The exhaust port 45 is connected in communication with an outdoor air outlet 57 provided in the building 2 via an outdoor air outlet duct 58.

[0022] The outdoor air outlet 57 is an opening provided in the building 2, and is an opening for discharging the air in which the CO2 concentration has been increased by the CO2 separation system 1 to the outdoors.

[0023] The outside air outlet duct 58 is a duct that discharges air that has circulated inside the housing 10 to the outside of the housing 10, and connects the exhaust port 45 and the outdoor outlet 57. The outside air outlet duct 58 functions as an exhaust air passage. Air with a high CO2 concentration, generated in the process of reducing the CO2 concentration in the target space by the CO2 separation system 1, passes through the exhaust port 45, the outside air outlet duct 58, and the outdoor outlet 57, and is discharged outdoors.

[0024] Inside the housing 10, there are installed a CO2 separation element 20, an indoor air fan 31 (circulation fan), an indoor air filter 37, an outdoor air fan 41, an outdoor air filter 47, a first flow rate adjustment unit 4a, a second flow rate adjustment unit 4b, a third flow rate adjustment unit 4c, and a fourth flow rate adjustment unit 4d, collectively referred to as flow rate adjustment units 4, a control unit 5, an indoor air CO2 concentration detection unit 7, and a first backflow prevention unit 8a and a second backflow prevention unit 8b, collectively referred to as backflow prevention unit 8.

[0025] There are four spaces inside the housing 10. Of the four spaces, the space communicating with the inside air port 33 is the inside air space 23, the space communicating with the air supply port 35 is the supply air space 24, the space communicating with the air supply port 35 is the outside air space 25, and the space communicating with the air exhaust port 45 is the exhaust space 26. The inside air space 23 and the exhaust space 26 are adjacent to each other via a partition wall 27. The air supply space 24 and the outside air space 25 are adjacent to each other via a partition wall 28.

[0026] The partition wall 27 is a structure provided inside the housing 10, and separates the internal air space 23 from the exhaust space 26. The partition wall 27 is provided with a second flow rate adjuster 4b.

[0027] The partition wall 28 is a structure provided inside the housing 10, and separates the air supply space 24 from the outside air space 25. The partition wall 28 is provided with a fourth flow rate adjuster 4d.

[0028] The internal air space 23 is a space partitioned by the partition wall 27, the second flow rate control unit 4b, and the CO2 separation element 20, and is a space that communicates with the internal air port 33. The internal air space 23 is adjacent to the exhaust space 26 via the second flow rate control unit 4b and the partition wall 27, and is adjacent to the supply air space 24 via the CO2 separation element 20.

[0029] The air supply space 24 is a space partitioned by the partition wall 28, the fourth flow rate control unit 4d, and the CO2 separation element 20, and is a space that is connected in communication with the air supply port 35. The air supply space 24 is adjacent to the outside air space 25 via the fourth flow rate control unit 4d and the partition wall 28, and is adjacent to the inside air space 23 via the CO2 separation element 20.

[0030] The outside air space 25 is a space partitioned by the partition wall 28, the fourth flow rate adjustment unit 4d, and the CO2 separation element 20, and is a space that is connected in communication with the outside air port 43. It is adjacent to the supply space 24 via the aligning portion 4d and the partition wall 28, and adjacent to the exhaust space 26 via the CO2 separation element 20.

[0031] The exhaust space 26 is a space partitioned by the partition wall 27, the second flow rate control unit 4b, and the CO2 separation element 20, and is a space that is connected in communication with the exhaust port 45. The exhaust space 26 is adjacent to the inside air space 23 via the second flow rate control unit 4b and the partition wall 27, and is adjacent to the outside air space 25 via the CO2 separation element 20.

[0032] The CO2 separation element 20 functions as a CO2 separator, separating CO2 from the inside air that has flowed through the inside air inlet duct 52 and introducing the CO2 into the outside air that has flowed through the outside air inlet duct 56. In other words, the CO2 separation element 20 is a member that selectively allows CO2 to pass from the inside air to the outside air. The CO2 separation element 20 is configured, for example, by stacking multiple CO2 separation membranes 22 so that a certain distance is created between each membrane.

[0033] Here, an overview of CO2 separation by the CO2 separation element 20 will be described. FIG. 2 is a diagram illustrating an overview of the CO2 separation element 20, and is a cross-sectional view showing a simplified configuration of the CO2 separation element 20. In the CO2 separation element 20, an internal internal air passage 16, through which internal air flows from left to right, and an internal external air passage 17, through which external air flows from left to right, are arranged vertically stacked. A CO2 separation membrane 22 is disposed between the internal internal air passage 16 and the internal external air passage 17. The internal air introduced into the internal internal air passage 16 contains a mixture of CO2 18 and N219. Although O2 and other gases are also mixed in the actual air, these are omitted here for clarity of explanation. When the internal air flows along the CO2 separation membrane 22 within the internal internal air passage 16, the CO2 separation membrane 22 selectively allows CO2 18 in the internal air to permeate and discharges the CO2 18 to the external air in the internal external air passage 17. This reduces the concentration of CO218 in the inside air and increases the concentration of CO218 in the outside air. Internal inside air duct 16 is an air duct through which the inside air introduced into housing 10 from inside air port 33 flows, and the air that has flowed through internal inside air duct 16 is sent to the target space via air intake port 35. Internal outside air duct 17 is an air duct through which the outside air introduced into housing 10 from outside air port 43 flows, and the air that has flowed through internal outside air duct 17 is sent to the outdoors via exhaust port 45.

[0034] The internal air fan 31 is a blower installed in the internal air space 23 and draws internal air from the target space through the internal air port 33 to introduce the air into the internal air space 23. When the internal air fan 31 is driven, the route along which the internal air introduced from the target space through the internal air port 33 into the internal air space 23 is blown is changed under the control of the control unit 5, which will be described later. Specifically, the route is changed by combining a first route, in which the air passes through the internal air filter 37, the internal air fan 31, the first flow rate adjuster 4a, the CO2 separation element 20, and the first backflow suppression unit 8a to reach the supply air space 24 and is then discharged to the target space through the supply air port 35, and a second route, in which the air passes through the internal air filter 37, the internal air fan 31, and the fourth flow rate adjuster 4d to reach the exhaust space 26 and is then discharged to the outdoors through the exhaust port 45.

[0035] The internal air filter 37 is a filter provided in the internal air space 23, which removes dirt, dust, etc. from the internal air that flows into the housing 10 and supplies the purified air to the CO2 separation element 20, and is, for example, a HEPA (High Efficiency Particulate Air) filter.

[0036] The outdoor air fan 41 is a blower that is installed in the outdoor air space 25 and introduces outdoor air into the outdoor air space 25 by drawing in the outdoor air through the outdoor air port 43. By driving the outdoor air fan 41, the outdoor air introduced into the outdoor air space 25 from the outdoors through the outdoor air port 43 changes its blowing path under the control of the control unit 5, which will be described later. Specifically, the outdoor air passes through the outdoor air filter 47, the outdoor air fan 41, the third flow rate adjustment unit 4c, the CO2 separation element 20, and the second backflow suppression unit 8b and is then blown out to the exhaust space 25. The route changes by combining a third route, which reaches 26 and is discharged outdoors through exhaust port 45, and a fourth route, which reaches air supply space 24 via outdoor air filter 47, outdoor air fan 41 and fourth flow rate adjustment unit 4d, and is discharged to the target space through air supply port 35.

[0037] The outside air filter 47 is provided in the outside air space 25, and is a filter that removes dirt, dust, etc. from the outside air that has flowed into the housing 10 and supplies the purified air to the CO2 separation element 20, and is, for example, a HEPA filter.

[0038] The inside air CO2 concentration detector 7 is attached to the inside air intake duct 52 and detects the CO2 concentration of the inside air flowing through the inside air intake duct 52. Known techniques may be used to detect the CO2 concentration, and therefore a description thereof will be omitted here. Information relating to the CO2 concentration detected by the inside air CO2 concentration detector 7 is transmitted to the control unit 5.

[0039] The flow rate adjustment unit 4 is a member that adjusts the flow rate of the air that flows in. The flow rate adjustment unit 4 includes a first flow rate adjustment unit 4a, a second flow rate adjustment unit 4b, a third flow rate adjustment unit 4c, and a fourth flow rate adjustment unit 4d.

[0040] The first flow rate adjuster 4a is provided adjacent to the CO2 separation element 20 in the interior air space 23 and is a valve or damper that adjusts the flow rate of air flowing into the CO2 separation element 20. When the first flow rate adjuster 4a is closed, air in the interior air space 23 does not flow into the CO2 separation element 20, and when the first flow rate adjuster 4a is open, air in the interior air space 23 flows into the CO2 separation element 20. In addition, the flow rate of air flowing into the CO2 separation element 20 can be adjusted by adjusting the opening degree of the first flow rate adjuster 4a.

[0041] The second flow rate adjustment unit 4b is provided in the partition wall 27 that separates the interior air space 23 and the exhaust space 26, and is a valve or damper that adjusts the flow rate of air flowing from the interior air space 23 to the exhaust space 26. The second flow rate adjustment unit 4b functions as a second connection unit. When the second flow rate adjustment unit 4b is closed, air in the interior air space 23 does not flow into the exhaust space 26, and when the second flow rate adjustment unit 4b is open, air in the interior air space 23 flows into the exhaust space 26. The flow rate of air flowing into the exhaust space 26 can be adjusted by adjusting the opening degree of the second flow rate adjustment unit 4b.

[0042] The third flow rate adjuster 4c is provided adjacent to the CO2 separation element 20 in the outside air space 25 and is a valve or damper that adjusts the flow rate of air flowing into the CO2 separation element 20. When the third flow rate adjuster 4c is closed, air in the outside air space 25 does not flow into the CO2 separation element 20, and when the third flow rate adjuster 4c is open, air in the outside air space 25 flows into the CO2 separation element 20. In addition, the flow rate of air flowing into the CO2 separation element 20 can be adjusted by adjusting the opening degree of the third flow rate adjuster 4c.

[0043] The fourth flow rate adjuster 4d is provided in the partition wall 28 that separates the air supply space 24 and the outdoor air space 25, and is a valve or damper that adjusts the flow rate of air flowing from the outdoor air space 25 into the air supply space 24. The fourth flow rate adjuster 4d functions as a first connection part. When the fourth flow rate adjuster 4d is closed, air in the outdoor air space 25 does not flow into the air supply space 24, and when the fourth flow rate adjuster 4d is open, air in the outdoor air space 25 flows into the air supply space 24. Furthermore, the flow rate of air flowing into the air supply space 24 can be adjusted by adjusting the opening degree of the fourth flow rate adjuster 4d.

[0044] The control unit 5 receives the CO2 concentration of the inside air detected by the inside air CO2 concentration detection unit 7, and controls the airflow rates of the inside air fan 31 and the outside air fan 41, and the air flow rate in the flow rate adjustment unit 4. A specific control method will be described later.

[0045] The subject of the device, system, or method of the present disclosure includes a computer. The computer executes a program to realize the functions of the subject of the device, system, or method of the present disclosure. The computer includes, as its main hardware component, a processor that operates according to the program. The processor may be of any type, as long as it can realize the functions by executing the program. The processor may be composed of one or more electronic circuits, including a semiconductor integrated circuit (IC) or a large-scale integration (LSI). The electronic circuits may be integrated into a single chip or may be provided on multiple chips. The multiple chips may be integrated into a single device or may be provided on multiple devices. The program is recorded on a non-transitory recording medium, such as a computer-readable ROM, optical disk, or hard disk drive. The program may be pre-stored on the recording medium or may be supplied to the recording medium via a wide-area communication network, including the Internet.

[0046] The backflow suppression unit 8 is a member that suppresses the backflow of air in the second path or the fourth path. The CO2 separation system 1 includes, as the backflow suppression unit 8, a first backflow suppression unit 8a and a second backflow suppression unit 8b.

[0047] The first backflow suppression unit 8a is provided adjacent to the CO2 separation element 20 on the supply air space 24 side and suppresses air in the supply air space 24 from flowing into the CO2 separation element 20. Specifically, the first backflow suppression unit 8a suppresses air that flows from the outside air space 25 into the supply air space 24 via the fourth flow rate adjuster 4d in the fourth path from flowing into the CO2 separation element 20, allowing the air to flow into the supply air passage. A check damper or the like can be used as the first backflow suppression unit 8a. Specifically, when air flows from the outside air space 25 into the supply air space 24 via the fourth flow rate adjuster 4d in the fourth path, if the pressure in the supply air space 24 rises and exceeds the outlet pressure of the CO2 separation element 20, air will flow back from the supply air space 24 to the CO2 separation element 20. However, when a check damper is used as the first backflow suppression unit 8a, the blades mounted on the check damper close to block the flow path, thereby preventing the backflow of air.

[0048] The second backflow suppression unit 8b is disposed adjacent to the CO2 separation element 20 on the exhaust space 26 side and prevents air in the outside air space 25 from flowing into the CO2 separation element 20. Specifically, the second backflow suppression unit 8b prevents air that flows from the inside air space 23 into the exhaust space 26 via the second flow rate adjuster 4b in the second path from flowing into the CO2 separation element 20, allowing the air to flow into the exhaust air passage. A check damper or the like can be used as the second backflow suppression unit 8b. Specifically, when air flows from the inside air space 23 into the exhaust space 26 via the second flow rate adjuster 4b in the second path, if the pressure in the exhaust space 26 rises and exceeds the outlet pressure of the CO2 separation element 20, air will flow back from the exhaust space 26 to the CO2 separation element 20. However, if a check damper is used as the second backflow suppression unit 8b, the blades mounted on the check damper close to block the flow path, preventing the backflow of air.

[0049] The above is the configuration of the CO2 separation system 1.

[0050] Next, we will explain the operation of the CO2 separation system 1. The CO2 separation system 1 is controlled by the flow rate regulator 4 to operate in a combination of a first state in which the air in the target space is circulated through the CO2 separation element 20 to reduce the CO2 concentration, and a second state in which the target space is ventilated.

[0051] First, the air flow when the CO2 separation system 1 is operated in the first state will be described with reference to Fig. 3. Fig. 3 is a diagram showing the air flow in the first state in this embodiment.

[0052] When the CO2 concentration is reduced in the first state, the indoor air fan 31 and the outdoor air fan 41 are operated. In the first state, air moved by the driving of the indoor air fan 31 is referred to as air 39a, and air moved by the driving of the outdoor air fan 41 is referred to as air 49a. By driving the indoor air fan 31, air with a high CO2 concentration present in the target space is drawn in through the indoor air inlet 51, passes through the indoor air introduction duct 52, and is introduced into the indoor air space 23 through the indoor air port 33. By introducing the air into the indoor air space 23, air 39a within the indoor air space 23 flows into the CO2 separation element 20 at a flow rate adjusted by the first flow rate adjuster 4a. At the same time, outdoor air drawn in through the outdoor air inlet 55 by the driving of the outdoor air fan 41 passes through the outdoor air introduction duct 56 and is introduced into the outdoor air space 25 through the outdoor air port 43. As a result of the introduction of air into the outdoor air space 25, air 49a within the outdoor air space 25 flows into the CO2 separation element 20 at a flow rate adjusted by the third flow rate adjuster 4c. At this time, air 49a has a higher CO2 concentration than air 49a, and the CO2 concentration of air 39a decreases due to the effect of the CO2 separation element 20. The air 39a with a reduced CO2 concentration is introduced into the air supply space 24, travels from the air supply port 35 through the indoor air outlet duct 54 to the indoor air outlet 53, and is then released into the target space through the indoor air outlet 53. At the same time, the CO2 concentration of air 49a increases due to the effect of the CO2 separation element 20. The air with the increased CO2 concentration is introduced into the exhaust space 26, travels from the exhaust port 45 through the outdoor air outlet duct 58 to the outdoor air outlet 57, and is then discharged outdoors through the outdoor air outlet 57. This is the air flow in the first state.

[0053] Next, the air flow when the CO2 separation system 1 is operated in the second state will be described with reference to Fig. 4. Fig. 4 is a diagram showing the air flow in the second state in this embodiment.

[0054] When operating in the second state, the indoor air fan 31 and the outdoor air fan 41 are operated. In the second state, air moved by the driving of the indoor air fan 31 is referred to as air 39b, and air moved by the driving of the outdoor air fan 41 is referred to as air 49b. When the indoor air fan 31 is driven, air with a high CO2 concentration present in the target space is drawn in through the indoor air inlet 51, passes through the indoor air introduction duct 52, and is introduced into the indoor air space 23 through the indoor air port 33. Of the air in the indoor air space 23, air 49a at a flow rate adjusted by the second flow rate adjuster 4b enters the exhaust space 26, passes through the exhaust port 45, reaches the outdoor air outlet 57 through the outdoor air outlet 57, and is discharged to the outdoors through the outdoor air outlet 57. At the same time, outdoor air drawn in through the outdoor air inlet 55 by the driving of the outdoor air fan 41 passes through the outdoor air introduction duct 56 and is introduced into the outdoor air space 25 through the outdoor air port 43. Of the air in the outdoor air space 25, air 49b with a flow rate adjusted by the fourth flow rate adjustment unit 4d is introduced into the air supply space 24, travels from the air supply port 35 through the indoor air outlet duct 54 to the indoor air outlet 53, and is released into the target space from the indoor air outlet 53.

[0055] Thus, the indoor air circulates indoors in the first state and is exhausted outdoors in the second state. The CO2 separation system 1 reduces the CO2 concentration in the target space by simultaneously operating the first and second states at a predetermined flow rate. The predetermined flow rate is determined, for example, according to the CO2 concentration detected by the indoor air CO2 concentration detection unit 7. Air 39a with a reduced CO2 concentration in the first state and air 39b introduced from outdoors in the second state are mixed in the air supply space 24 and discharged into the target space through the indoor air outlet duct 54. At the same time, air 49a with an increased CO2 concentration in the first state and air 49b introduced from the target space in the second state are mixed in the exhaust space 26 and discharged outdoors through the outdoor air outlet duct 58. In this way, the CO2 separation system 1 releases CO2 from the indoor air to the outdoor air, thereby suppressing an increase in the CO2 concentration in the target space.

[0056] The flow rate control in the flow rate adjustment unit 4 is performed as follows. In this embodiment, the CO2 concentration of the inside air is measured by the inside air CO2 concentration detection unit 7. The measured CO2 concentration of the inside air is transmitted to the control unit 5, and the control unit 5 outputs a flow rate control signal corresponding to the CO2 concentration to the flow rate adjustment unit 4. At this time, the higher the CO2 concentration measured by the inside air CO2 concentration detection unit 7, the lower the CO2 The flow rate is controlled so as to increase the CO2 removal capacity in the separation system 1. A specific control operation will be described below.

[0057] The CO2 separation element 20 has an inherent upper limit of CO2 separation capacity depending on the size or characteristics of the element. Therefore, if air is blown into the CO2 separation element 20 at a flow rate above a certain level, the upper limit of CO2 separation capacity may be exceeded, and proper CO2 separation may not be possible. Therefore, a reference value for CO2 separation capacity is set, and flow rate control is performed based on this reference value. For example, the upper limit of the separation capacity of the CO2 separation element 20, or the CO2 separation capacity at the maximum blowing rate determined by the pressure loss characteristics of the CO2 separation element 20, can be used as the reference value.

[0058] Specifically, the required CO2 removal amount is first determined based on the CO2 concentration measured by the indoor air CO2 concentration detection unit 7. For example, if the CO2 concentration measured by the indoor air CO2 concentration detection unit 7 is 700 ppm or less, a first CO2 removal amount equivalent to the CO2 emission of one person is determined; if the CO2 concentration is 700 ppm or more but less than 1000 ppm, a second CO2 removal amount equivalent to the CO2 emission of three people is determined; and if the CO2 concentration is 1000 ppm or more, a maximum CO2 removal amount of the CO2 separation system 1 is determined. The second CO2 removal amount is greater than the first CO2 removal amount, and the maximum CO2 removal amount is greater than the second CO2 removal amount. When the required CO2 removal amount is less than the reference value of the CO2 separation capacity, the second flow rate adjustment unit 4b and the fourth flow rate adjustment unit 4d are closed, resulting in an air path configuration that prevents air movement between the indoor air space 23 and the exhaust space 26 and between the supply air space 24 and the outdoor air space 25. That is, when the CO2 separation capacity is equal to or less than the reference value, the CO2 separation system 1 operates only in the first state.

[0059] On the other hand, if the required CO2 removal amount based on the CO2 concentration measured by the inside air CO2 concentration detection unit 7 exceeds the reference value of the CO2 separation capacity, the second flow rate adjustment unit 4b and the fourth flow rate adjustment unit 4d are opened and their opening degrees are adjusted in accordance with a signal from the control unit 5. The first flow rate adjustment unit 4a and the third flow rate adjustment unit 4c are also adjusted in accordance with a signal from the control unit 5 so that the flow rate is smaller than the flow rate in the first state alone. The opening degrees of the first flow rate adjustment unit 4a, the second flow rate adjustment unit 4b, the third flow rate adjustment unit 4c, and the fourth flow rate adjustment unit 4d are adjusted based on the CO2 concentration measured by the inside air CO2 concentration detection unit 7. When air is blown at the same flow rate, the CO2 removal capacity by ventilation exceeds the CO2 separation capacity of the CO2 separation element 20. Therefore, by reducing the flow rate in the first state and increasing the flow rate in the second state, the CO2 removal capacity of the CO2 separation system 1 as a whole is increased. Therefore, when the required amount of CO2 removal exceeds the reference value of the CO2 separation capacity and it is desired to reduce the CO2 concentration quickly, the apertures of the second flow rate regulator 4b and the fourth flow rate regulator 4d are increased and the apertures of the first flow rate regulator 4a and the third flow rate regulator 4c are decreased. In other words, when the required amount of CO2 removal exceeds the reference value of the CO2 separation capacity, the airflow rate in the first state is reduced and airflow in the second state is started. This allows the CO2 concentration to be reduced more quickly than when operating only in the first state.

[0060] When the required CO2 removal rate falls below the reference value for CO2 separation capacity while operating in a combination of the first and second modes, the second flow rate regulator 4b and the fourth flow rate regulator 4d are closed, and the unit operates in the first mode only. This is because operating in the first mode only reduces heat loss more effectively than operating in a combination of the first and second modes. After adjusting the airflow rate to reduce the CO2 removal rate, the airflow rate may be adjusted again due to an increase in the CO2 concentration in the target space. If this occurs repeatedly, the airflow rate may be adjusted frequently near the threshold. To avoid this, it is preferable to control the airflow rate to reduce the CO2 removal rate, for example, when the CO2 concentration measured by the indoor air CO2 concentration detector 7 remains below the threshold for 30 minutes.

[0061] By controlling in this way, CO2 separation and ventilation can be combined depending on the CO2 concentration. Therefore, the CO2 separation system 1 can be configured to quickly reduce the CO2 concentration while suppressing heat loss according to the CO2 concentration in the target space.

[0062] As described above, the CO2 separation system 1 according to this embodiment can provide the following effects.

[0063] (1) The CO2 separation system 1 is a CO2 separation system equipped with a CO2 separation unit (CO2 separation element 20) that separates CO2 from circulating air. The system has two modes: a first mode in which air from a target indoor space is circulated through the CO2 separation unit and air with a reduced CO2 concentration is blown into the target space; and a second mode in which the target space is ventilated. The system is equipped with a control unit 5 that controls the first and second modes. The CO2 separation unit operates to increase its CO2 separation capacity as the CO2 concentration of the air in the target space increases. The control unit 5 operates in the first mode until the CO2 separation capacity of the CO2 separation unit reaches a reference value, and when the reference value is exceeded, the control unit 5 operates in a combination of the first and second modes.

[0064] This configuration allows the CO2 separation system 1 to operate in combination with CO2 separation and ventilation depending on the CO2 concentration, thereby enabling the CO2 separation system 1 to quickly reduce the CO2 concentration in the target space while suppressing heat loss according to the CO2 concentration.

[0065] (2) When the reference value of the CO2 separation capacity is exceeded, the control unit 5 reduces the amount of air blown in the first state and starts blowing air in the second state. This allows ventilation while reducing the amount of air blown to the CO2 separation element 20 compared to before the reference value of the CO2 separation capacity was exceeded.

[0066] (Embodiment 2) The CO2 separation system 1b according to this embodiment differs from the CO2 separation system 1 according to embodiment 1 in the configuration of the first state and the second state and the control method in the first state and the second state. The configuration other than this is the same as that of the CO2 separation system 1 according to embodiment 1. Below, the content already explained in embodiment 1 will not be explained again as appropriate, and the differences from embodiment 1 will be mainly explained.

[0067] A CO2 separation system 1b according to the second embodiment will be described with reference to Fig. 5. Fig. 5 is a schematic diagram of a CO2 separation system according to a second embodiment.

[0068] The CO2 separation system 1b does not include the flow rate regulator 4 in the configuration of the CO2 separation system 1 according to the first embodiment, but instead includes an exhaust fan 32 and an air supply fan 42. The rest of the configuration is the same as that of the CO2 separation system 1, and therefore a description thereof will be omitted.

[0069] The exhaust fan 32 is provided in the partition wall 27 that separates the internal air space 23 and the exhaust space 26, and is a blower that adjusts the flow rate of air flowing from the internal air space 23 to the exhaust space 26. Driving the exhaust fan 32 causes air to move from the internal air space 23 to the exhaust space 26. The exhaust fan 32 operates at the same timing as the second flow rate adjuster 4b, so that the exhaust fan 32 does not operate in the first state and operates in the second state. Furthermore, by adjusting the airflow rate of the exhaust fan 32, the flow rate of air flowing into the exhaust space 26 can be adjusted.

[0070] The intake fan 42 is provided on the partition wall 28 that separates the intake space 24 and the outdoor air space 25, and is a blower that adjusts the flow rate of air flowing from the outdoor air space 25 into the intake space 24. Driving the intake fan 42 causes air to move from the outdoor air space 25 to the intake space 24. The intake fan 42 operates at the same timing as the fourth flow rate adjuster 4d, so that the intake fan 42 does not operate in the first state, but operates in the second state. In addition, by adjusting the airflow rate of the exhaust fan 32, the flow rate of air flowing into the exhaust space 26 can be adjusted. can.

[0071] The above is the configuration of the CO2 separation system 1b.

[0072] Next, the operation of the CO2 separation system 1b will be described. The CO2 separation system 1b controls the exhaust fan 32 and the supply fan 42 to operate in a combination of a first state in which the air in the target space is circulated through the CO2 separation element 20 to reduce the CO2 concentration, and a second state in which the target space is ventilated.

[0073] First, the air flow when the CO2 separation system 1b is operated in the first state will be described with reference to Fig. 6. Fig. 6 is a diagram showing the air flow in the first state in this embodiment.

[0074] When reducing the CO2 concentration in the first state, the indoor air fan 31 and the outdoor air fan 41 are operated. In the first state, air moved by the driving of the indoor air fan 31 is referred to as air 39a, and air moved by the driving of the outdoor air fan 41 is referred to as air 49a. By driving the indoor air fan 31, air with a high CO2 concentration present in the target space is drawn in through the indoor air inlet 51, passes through the indoor air introduction duct 52, and is introduced into the indoor air space 23 through the indoor air port 33. By introducing the air into the indoor air space 23, air 39a in an amount corresponding to the airflow rate of the indoor air fan flows into the CO2 separation element 20. At the same time, outdoor air drawn in through the outdoor air inlet 55 by the driving of the outdoor air fan 41 passes through the outdoor air introduction duct 56 and is introduced into the outdoor air space 25 through the outdoor air port 43. As air is introduced into the outdoor air space 25, air 49a in the outdoor air space 25 flows into the CO2 separation element 20 in an amount corresponding to the airflow rate of the outdoor air fan 41. At this time, air 49a has a higher CO2 concentration than air 49a, and the CO2 concentration of air 39a decreases due to the effect of the CO2 separation element 20. The air 39a with a decreased CO2 concentration is introduced into the air supply space 24, travels from the air supply port 35 through the indoor air outlet duct 54 to the indoor air outlet 53, and is released into the target space through the indoor air outlet 53. At the same time, the CO2 concentration of air 49a increases due to the effect of the CO2 separation element 20. The air with the increased CO2 concentration is introduced into the exhaust space 26, travels from the exhaust port 45 through the outdoor air outlet duct 58 to the outdoor air outlet 57, and is discharged outdoors through the outdoor air outlet 57. This is the air flow in the first state. Note that the exhaust fan 32 and the intake fan 42 are not operating at this time.

[0075] Next, the air flow when the CO2 separation system 1b is operated in the second state will be described with reference to Fig. 7. Fig. 7 is a diagram showing the air flow in the second state in this embodiment.

[0076] When operating in the second state, in addition to the indoor air fan 31 and the outdoor air fan 41, the exhaust fan 32 and the supply air fan 42 are also operated. In the second state, air moved by the driving of the indoor air fan 31 is referred to as air 39b, and air moved by the driving of the outdoor air fan 41 is referred to as air 49b. By driving the indoor air fan 31, air with a high CO2 concentration present in the target space is drawn in through the indoor air inlet 51, passes through the indoor air introduction duct 52, and is introduced into the indoor air space 23 through the indoor air port 33. Here, because the exhaust fan 32 is operating, air 39b from the indoor air space 23 flows into the exhaust space 26 at a flow rate corresponding to the airflow rate of the exhaust fan 32. The air 39b that has flowed into the exhaust space 26 travels from the exhaust port 45 through the outdoor air outlet duct 58 to the outdoor outlet 57 and is then discharged outdoors through the outdoor outlet 57. At the same time, outside air drawn in through outdoor air inlet 55 by driving outside air fan 41 passes through outside air introduction duct 56 and is introduced into outside air space 25 through outside air outlet 43. Here, because supply air fan 42 is operating, air 49b in outside air space 25 flows into air supply space 24 at a flow rate corresponding to the airflow rate of supply air fan 42. Air 49b that has flowed into air supply space 24 travels from air supply port 35 through inside air outlet duct 54 to indoor outlet 53, and is released from indoor outlet 53 into the target space.

[0077] In this way, the indoor air is circulated indoors in the first state and exhausted outdoors in the second state. In the O2 separation system 1b, the CO2 concentration in the target space is reduced by simultaneously operating the first and second states at a predetermined flow rate. The predetermined flow rate is determined, for example, according to the CO2 concentration detected by the indoor air CO2 concentration detection unit 7. At this time, air 39a whose CO2 concentration has been reduced in the first state and air 49b introduced from outdoors in the second state are mixed in the air supply space 24 and discharged into the target space through the indoor air discharge duct 54. At the same time, air 49a whose CO2 concentration has been increased in the first state and air 39b introduced from within the target space in the second state are mixed in the exhaust space 26 and discharged outdoors through the outdoor air discharge duct 58. In this way, the CO2 separation system 1b discharges CO2 from indoor air to outdoor air, thereby suppressing an increase in the CO2 concentration in the target space.

[0078] The airflow rates of exhaust fan 32 and intake fan 42 are controlled as follows. In this embodiment, the CO2 concentration of the inside air is measured by inside air CO2 concentration detection unit 7. The measured CO2 concentration of the inside air is sent to control unit 5, and control unit 5 outputs a flow rate control signal corresponding to the CO2 concentration to exhaust fan 32 and intake air fan 42. At this time, the flow rate is controlled so that the higher the CO2 concentration measured by inside air CO2 concentration detection unit 7, the higher the CO2 removal capacity of CO2 separation system 1b. Specific control operations are described below.

[0079] The CO2 separation element 20 has an inherent upper limit of CO2 separation capacity depending on its size or characteristics. Therefore, if air is blown through the CO2 separation element 20 at a flow rate above a certain level, the upper limit of CO2 separation capacity may be exceeded, potentially resulting in inadequate CO2 separation. Therefore, a standard value for CO2 separation capacity is established, and flow control is performed based on this standard value. Examples of the standard value include the upper limit of the separation capacity of the CO2 separation element 20 or the upper limit of fan power consumption associated with CO2 separation, calculated by back-calculating the required energy-saving performance of the entire CO2 separation system 1b. For example, the CO2 separation element 20 increases its CO2 separation capacity more slowly when the airflow rate is increased as the CO2 separation capacity approaches its upper limit. Therefore, when increasing the amount of CO2 removal by the amount equivalent to the CO2 emissions per person, the combined heat loss and fan power consumption resulting from increasing the ventilation airflow may be lower than the increase in fan power consumption associated with increasing the CO2 separation airflow rate. In such cases, increasing the CO2 separation capacity does not result in energy savings, and therefore a standard value for CO2 separation capacity is established.

[0080] Specifically, the control operation first determines the required CO2 removal amount based on the CO2 concentration measured by the indoor air CO2 concentration detection unit 7. For example, if the CO2 concentration measured by the indoor air CO2 concentration detection unit 7 is 700 ppm or less, a first CO2 removal amount equivalent to the CO2 emissions of one person is determined; if the CO2 concentration is 700 ppm to 1000 ppm, a second CO2 removal amount equivalent to the CO2 emissions of three people is determined; and if the CO2 concentration is 1000 ppm or more, a maximum CO2 removal amount of the CO2 separation system 1b is determined. The second CO2 removal amount is greater than the first CO2 removal amount, and the maximum CO2 removal amount is greater than the second CO2 removal amount. If the required CO2 removal amount is less than the CO2 separation capacity reference value, the exhaust fan 32 and the supply air fan 42 stop operating, and an air path configuration is established to prevent air movement between the indoor air space 23 and the exhaust space 26 and between the supply air space 24 and the outdoor air space 25. That is, when the CO2 separation capacity is equal to or less than the reference value, the CO2 separation system 1b operates only in the first state.

[0081] On the other hand, if the required amount of CO2 removal based on the CO2 concentration measured by the inside air CO2 concentration detection unit 7 exceeds the reference value of the CO2 separation capacity, the exhaust fan 32 and the intake air fan 42 start operating in accordance with a signal from the control unit 5. Specifically, if the required amount of CO2 removal exceeds the reference value of the CO2 separation capacity, the air blowing in the second state starts while maintaining the air blowing volume in the first state. This allows ventilation to be performed in parallel with CO2 separation, which is performed in the first state, so the CO2 concentration can be reduced quickly.

[0082] When the required CO2 removal rate falls below the reference value for CO2 separation capacity while operating in a combination of the first and second modes, the exhaust fan 32 and the intake fan 42 are stopped and the unit operates in the first mode only. This is because operating in the first mode only reduces heat loss more effectively than operating in a combination of the first and second modes. After adjusting the airflow rate to reduce the CO2 removal rate, the airflow rate may be adjusted again due to an increase in the CO2 concentration in the target space. If this occurs repeatedly, the airflow rate may be adjusted frequently near the threshold. To avoid this, it is preferable to control the unit so that the airflow rate is adjusted to reduce the CO2 removal rate when the CO2 concentration measured by the indoor air CO2 concentration detection unit 7 remains below the threshold for 30 minutes.

[0083] By performing such control, it is possible to operate a combination of CO2 separation and ventilation depending on the CO2 concentration, resulting in a CO2 separation system 1b that can quickly reduce the CO2 concentration while suppressing heat loss depending on the CO2 concentration in the target space.

[0084] As described above, according to the CO2 separation system 1b of this embodiment, in addition to the effect (1) obtained by the CO2 separation system 1 of the first embodiment, the following effect can be obtained.

[0085] (3) The CO2 separation system 1b includes an internal air fan 31 that blows air from the return air duct (internal air duct 52) ​​to the supply air duct (supply air duct 54), and an exhaust fan 32 that blows air from the return air duct (internal air duct 52) ​​to the exhaust air duct (exhaust duct 58). When the CO2 separation capacity of the CO2 separation unit (CO2 separation element 20) exceeds a reference value, the control unit 5 starts operation of the exhaust fan 32 while maintaining the airflow rate of the internal air fan 31. This allows CO2 separation in the CO2 separation unit (CO2 separation element 20) to be performed while exhausting the air, thereby efficiently reducing the CO2 concentration in the target space.

[0086] The present invention has been described above based on the embodiments. These embodiments are merely examples, and it will be understood by those skilled in the art that various modifications are possible in the combination of each component or each treatment process, and that such modifications are also within the scope of the present invention.

[0087] In the first embodiment, the inside air fan 31 is provided in the inside air space 23. However, this is not limiting. For example, the inside air fan 31 may be provided in a location upstream of the inside air space 23 and connected to the inside air space 23 (e.g., in the inside air inlet duct 52), in the supply air space 24, or in a location downstream of the supply air space 24 and connected to the supply air space 24 (e.g., in the inside air outlet duct 54). In this case, by driving the inside air fan 31, inside air is drawn in from the target space through the inside air port 33 and passes through the inside air filter 37, the first flow rate adjuster 4a, the CO2 separation element 20, and the first backflow suppression unit 8a before reaching the supply air space 24. Furthermore, by driving the inside air fan 31, outside air is drawn in through the outside air port 43. The drawn outside air passes through the outside air filter 47 and the fourth flow rate adjuster 4d and reaches the supply air space 24. The air that has reached the supply air space is discharged to the target space through the air intake port 35.

[0088] In the first embodiment, the outdoor air fan 41 is provided in the outdoor air space 25, but this is not limiting. For example, the outdoor air fan 41 may be provided in a location upstream of the outdoor air space 25 and connected to the outdoor air space 25 (for example, in the outdoor air intake duct 56), or in the exhaust space 26, or in a location downstream of the exhaust space 26 and connected to the exhaust space 26 (for example, in the outdoor air outlet duct 58). In this case, outdoor air drawn in from the outdoors through the outdoor air port 43 by driving the outdoor air fan 41 reaches the exhaust space 26 via the outdoor air filter 47, the third flow rate adjuster 4c, the CO2 separation element 20, and the second backflow suppression unit 8b. In addition, indoor air is drawn in through the indoor air port 33 by driving the outdoor air fan 41. The drawn indoor air is then passed through the indoor air filter 47, the third flow rate adjuster 4c, the CO2 separation element 20, and the second backflow suppression unit 8b. The air passes through the filter 37 and the second flow rate adjuster 4b and reaches the exhaust space 26. The air that has reached the exhaust space 26 is discharged through the exhaust port 45 to the outdoors.

[0089] In the second state of the first embodiment, heat exchange may be performed between the first air blown from the outside air duct to the supply air duct and the second air blown from the return air duct to the exhaust air duct. For heat exchange, for example, a heat exchanger may be provided inside the housing 10, and a duct for introducing the first air into the heat exchanger, a duct for introducing the second air into the heat exchanger, a duct for introducing the heat-exchanged first air into the exhaust air duct, and a duct for introducing the heat-exchanged second air into the exhaust air duct may be connected to the heat exchanger. This allows heat exchange between the outside air and the inside air before flowing into the target space, thereby suppressing heat loss due to ventilation. The heat exchanger may be provided outside the housing 10. Alternatively, the heat-exchanged first air may be directly introduced into the target space. Similarly, the heat-exchanged second air may be directly exhausted to the outdoors. Alternatively, heat exchange may be performed between the return air from the target space and the outside air, and the heat-exchanged air may be supplied to the target space.

[0090] In the first embodiment, outdoor air is drawn into the housing 10 through the outdoor air inlet 43, but this is not limiting. The outdoor air does not necessarily have to be outdoor air, and may be, for example, air from a space outside the target space with a low CO2 concentration. When drawing in air from outside the target space, the outdoor air inlet 55 is provided in an appropriate location such as the ceiling.

[0091] An outline of one aspect of the present disclosure is as follows.

[0092] (Item 1) A CO2 separation system (1) including a CO2 separation unit that separates CO2 from flowing air, a first state in which air in a target space indoors is circulated through the CO2 separation unit (20) and air with a reduced CO2 concentration is blown into the target space; A second state in which the target space is ventilated, a control unit (5) that controls the first state and the second state, the CO2 separation unit (20) operates to increase its CO2 separation capacity as the CO2 concentration of the air in the target space increases; The control unit (5) The operation is performed in the first state until the CO2 separation capacity in the CO2 separation section (20) reaches a reference value, When the CO separation capacity exceeds the reference value, the first state and the second state are operated in combination. CO2 separation system (1).

[0093] (Item 2) The control unit (5) 2. The CO2 separation system (1) according to item 1, wherein, when the reference value is exceeded, the amount of air blown in the first state is reduced and air blown in the second state is started.

[0094] (Item 3) The control unit (5) Item 1. A CO2 separation system (1) according to item 1, wherein, when the reference value is exceeded, the air blowing volume in the first state is maintained until the reference value is reached, and the air blowing volume in the second state is increased.

[0095] (Item 4) a housing (10) having the CO2 separation unit (20) therein; an outside air duct (56) that allows outside air to flow into the housing (10); an exhaust air passage (58) for discharging air that has circulated inside the housing (10) to the outside of the housing (10); a return air duct (52) that allows air from the target space to flow into the housing (10); an air supply duct (54) for ventilating the air circulating inside the housing (10) to the target space, The control unit (5) In the first state, the outside air duct (56) and the exhaust air duct (58) are connected to each other through the CO2 separation unit, and the return air duct (52) and the supply air duct (54) are connected to each other through the CO2 separation unit (20), Item 1. The CO2 separation system (1) according to item 1, wherein, in the second state, the outside air duct (56) and the supply air duct (54) are connected in fluid communication with each other, and the return air duct (52) and the exhaust air duct (58) are connected in fluid communication with each other.

[0096] (Item 5) a first connection portion (4d) that is installed between the outside air duct (56) and the supply air duct (54) and that is capable of adjusting the flow rate of air that flows through; a second connection part (4b) that is installed between the return air duct (52) and the exhaust air duct (58) and that is capable of adjusting the flow rate of air passing through; The control unit (5) The first connecting portion (4d) and the second connecting portion (4b) are closed until the reference value is reached, 5. The CO2 separation system (1) according to item 4, wherein, when the reference value is exceeded, the opening degrees of the first connection part (4d) and the second connection part (4b) are adjusted according to the CO2 concentration in the target space, and air is blown in the second state.

[0097] (Item 6) an internal air fan (31) for blowing air from the return air duct (52) to the supply air duct (54); an exhaust fan (32) that blows air from the return air duct (52) to the exhaust air duct (58), The control unit (5) When the CO2 separation capacity of the CO2 separation unit (20) exceeds the reference value, 5. The CO2 separation system (1) according to item 4, wherein the exhaust fan (32) is started to operate while maintaining the airflow rate of the inside air fan (31).

[0098] (Item 7) In the second state, Heat exchange is performed between the first air blown from the outside air duct (56) to the supply air duct (54) and the second air blown from the return air duct (52) to the exhaust air duct (58). Item 4. The CO2 separation system (1) according to item 4. [Industrial Applicability]

[0099] The present invention is useful as a CO2 separation system or the like that can efficiently remove CO2 from a target space where many people are present. [Explanation of symbols]

[0100] 1 CO2 separation system 1b CO2 separation system 2. Building 4 Flow rate adjustment section 4a 1st flow rate adjustment section 4b 2nd flow rate adjustment section 4c 3rd flow rate adjustment section 4d 4th flow adjustment section 5. Control section 7. Inside air CO2 concentration detector 8 Backflow suppressor 8a 1st backflow suppressor 8b Second backflow suppressor 10. Cabinet 16 Internal air passage 17 Internal outside air passage 18 CO2 19 N2 20 CO2 separation element 22 CO2 separation membrane 23 Indoor air space 24 Air supply space 25 Outdoor air space 26 Exhaust space 27 Bulkhead 28 Bulkhead 31 Inner Fan 32 Exhaust fan 33 Internal air vent 35 Air supply port 37 Internal air filter 39a Air 39b Air 41 Outdoor air fan 42 Air supply fan 43 Outside air vent 45 exhaust port 47 Fresh air filter 49a Air 49b Air 51 Indoor air intake 52 Inside air intake duct 53 Indoor air outlet 54 Internal air outlet duct 55 Outdoor intake port 56 Outside air intake duct 57 Outdoor outlet 58 Outdoor air outlet duct

Claims

1. CO from the circulating air ２ CO ２ CO with separation section ２ 1. A separation system comprising: The air in the target space indoors is ２ The CO ２ a first state in which the air having a reduced concentration is blown into the target space; A second state in which the target space is ventilated, a control unit that controls the first state and the second state, The CO ２ The separation unit separates the CO ２ With increasing concentration, CO ２ Operates to increase separation capacity, The control unit The CO ２ The CO in the separation section ２ The operation is continued in the first state until the reference value of the separation capacity is reached, The CO ２ When the reference value of the separation capacity is exceeded, the first state and the second state are operated in combination. CO ２ Separation system.

2. The control unit When the reference value is exceeded, the air blowing amount in the first state is reduced, and air blowing in the second state is started. The CO according to claim 1 ２ Separation system.

3. The control unit When the reference value is exceeded, the airflow rate in the first state is maintained until the reference value is reached, and the airflow rate in the second state is increased. The CO according to claim 1 ２ Separation system.

4. Inside the CO ２ a housing having a separation portion; an outside air passage for allowing outside air to flow into the housing; an exhaust air duct that exhausts air that has circulated inside the housing to the outside of the housing; A return air duct that allows air from the target space to flow into the housing; an air supply duct that ventilates the air that has circulated inside the housing into the target space, The control unit In the first state, the outside air passage and the exhaust air passage are connected to the CO ２ The return air duct and the supply air duct are connected to each other via a separation part, and the CO ２ The communication connection is made via a separation part, In the second state, the outside air duct and the supply air duct are connected in communication with each other, and the return air duct and the exhaust air duct are connected in communication with each other. The CO according to claim 1 ２ Separation system.

5. a first connection portion that is installed between the outside air passage and the supply air passage and that is capable of adjusting the flow rate of air circulating; A second connection portion that is installed between the return air duct and the exhaust air duct and can adjust the flow rate of air circulating, The control unit The first connection portion and the second connection portion are closed until the reference value is reached; When the reference value is exceeded, the CO ２ adjusting the opening degrees of the first connection part and the second connection part according to the concentration, and blowing air in the second state; The CO according to claim 4 ２ Separation system.

6. an internal air fan that blows air from the return air duct to the supply air duct; an exhaust fan that blows air from the return air duct to the exhaust air duct, The control unit The CO ２ The CO in the separation section ２ When the separation capacity exceeds the standard value, start the operation of the exhaust fan while maintaining the airflow rate of the inside air fan; The CO according to claim 4 ２ Separation system.

7. In the second state, Heat exchange is performed between first air blown from the outside air duct to the supply air duct and second air blown from the return air duct to the exhaust air duct. The CO according to claim 4 ２ Separation system.

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