CO2 separation system

Abstract

To provide technique capable of reducing heat loss due to heat exchange even when inside air and outside air are used in order to separate CO2.SOLUTION: An inside air introduction duct 52 and an inside air outlet duct 54 introduce and circulate air in an object space indoors as inside air and return the air into the object space. An outside air introduction duct 56 and an outside air outlet duct 58 introduce and circulate air outdoors as outside air and release the air outdoors. A CO2 separation element 20 separates CO2 from the inside air flowing through the inside air introduction duct 52 so as to be introduced into the outside air flowing through the outside air introduction duct 56. A first temperature adjustment unit 4a and a second temperature adjustment unit 4b adjust at least one of a temperature of the inside air and a temperature of the outside air introduced into the CO2 separation element 20. A control unit 5 performs control so that a temperature difference between the temperature of the inside air and the temperature of the outside air introduced into the CO2 separation element 20 is smaller than a temperature difference between a temperature of the air in the object space and the temperature of the outdoor air.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a CO₂ separation system that separates CO₂ from air in a target space.

Background Art

[0002] In order to reduce the concentration of carbon dioxide (CO₂) in the air of a closed space unit, the air in the space unit is supplied to a purge gas membrane system. In the purge gas membrane system, since CO₂ preferentially permeates through the membrane module, air with reduced CO₂ remains. The remaining air is returned back to the space unit (see, for example, Patent Document 1).

Prior Art Literature

Patent Literature

[0003]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0004] In a CO₂ separation system, CO₂ is separated from the inside air in the space, and the separated CO₂ is mixed into purge gas and discharged. When outside air outside the space is used as the purge gas, heat exchange occurs between the inside air and the outside air, and heat loss due to the heat exchange becomes a problem.

[0005] The present disclosure has been made to solve the above problem, and an object of the present disclosure is to provide a technique for reducing heat loss due to heat exchange even when inside air and outside air are used for separating CO₂.

Means for Solving the Problem

[0006] To solve the above problems, a CO2 separation system in one aspect of the present disclosure comprises: an internal air passage through which air from a target space indoors is introduced as internal air, circulated, and returned to the target space; an external air passage through which outdoor air is introduced as external air, circulated, and released to the outside; a CO2 separation unit that separates CO2 from the internal air circulating in the internal air passage and introduces it into the external air circulating in the external air passage; a temperature control unit that adjusts at least one of the temperature of the internal air introduced into the CO2 separation unit and the temperature of the external air introduced into the CO2 separation unit; and a control unit that controls the temperature control unit. The control unit controls the temperature control unit so that the temperature difference between the temperature of the internal air introduced into the CO2 separation unit and the temperature of the external air introduced into the CO2 separation unit is smaller than the temperature difference between the temperature of the air in the target space and the temperature of the outdoor air.

[0007] Furthermore, any combination of the above components, as well as any conversion of the expressions of this disclosure between methods, apparatus, systems, recording media, computer programs, etc., are also valid as aspects of this disclosure. [Effects of the Invention]

[0008] According to this disclosure, even when using both indoor and outdoor air to separate CO2, heat loss due to heat exchange can be reduced. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic diagram showing an example of the installation of the CO2 separation system according to Example 1. [Figure 2] Figures 2(a) and 2(b) show an overview of the CO2 separation element shown in Figure 1. [Figure 3] Figure 3 shows the configuration of the CO2 separation element in Figure 1. [Figure 4] Figure 4 shows the data structure of the table held in the control unit of Figure 1. [Figure 5] Figure 5 shows the configuration of the CO2 separation system according to Example 2. [Modes for carrying out the invention]

[0010] (Example 1) The following examples will be described with reference to the drawings. Note that the following examples are merely illustrations of the present disclosure and do not limit the technical scope of the present disclosure. Furthermore, the figures described in the examples are schematic diagrams, and the ratios of the size and thickness of each component in each figure do not necessarily reflect the actual dimensional ratios.

[0011] Embodiments of this disclosure will be described with reference to the attached drawings. Figure 1 is a schematic diagram showing an example of the installation of the CO2 separation system 1. The CO2 separation system 1 is installed inside 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 space indoors. The CO2 separation system 1 includes a housing 10, a CO2 separation element 20, an internal fan 31, an internal filter 37, an external fan 41, an external filter 47, a first temperature control unit 4a, a second temperature control unit 4b, a control unit 5, an external temperature detection unit 7, and an internal temperature detection unit 8.

[0012] The enclosure 10 is the outer frame of the CO2 separation system 1. An inner air inlet 33, an air supply inlet 35, an outer air inlet 43, and an exhaust inlet 45 are arranged on the outer perimeter of the enclosure 10. The inner air inlet 33 is an intake port that draws air 39a into the CO2 separation system 1. The inner air inlet 33 is connected to an indoor intake port 51 provided in the building 2 by an indoor air introduction duct 52. The indoor intake port 51 is an opening provided in the target space of the building 2, and is an opening that introduces the air 39a (indoor air) from the target space as RA into the CO2 separation system 1. The indoor air introduction duct 52 is a duct that introduces indoor air into the enclosure 10. One end of the indoor air introduction duct 52 is connected to the indoor intake port 51, and RA from indoors flows into the indoor air introduction duct 52. The other end of the indoor air introduction duct 52 is connected to the inner air inlet 33, and RA is circulated into the enclosure 10. In other words, the air from the target space indoors is introduced into the indoor air intake duct 52 and circulates through it as indoor air.

[0013] The air intake port 35 is an outlet that discharges air 39b from the CO2 separation system 1. The air intake port 35 is connected to an indoor air outlet 53 provided in the building 2 by an indoor air discharge duct 54. The indoor air outlet 53 is an opening provided in the building 2 that supplies air 39b, whose CO2 concentration has been reduced by the CO2 separation element 20, to the target space as SA. The indoor air discharge duct 54 is a duct that supplies indoor air from the housing 10 to the target space. One end of the indoor air discharge duct 54 is connected to the air intake port 35, and air 39b, whose CO2 concentration has been reduced by the CO2 separation element 20, flows into the duct. The other end of the indoor air discharge duct 54 is connected to the indoor air outlet 53, and the air 39b in the duct is supplied to the target space as SA. In other words, the indoor air discharge duct 54 recirculates the air 39b back into the target space.

[0014] The outdoor air inlet 43 is an intake port that draws air 49a into the CO2 separation system 1. The outdoor air inlet 43 is connected to an outdoor intake port 55 provided in the building 2 by an outdoor air introduction duct 56. The outdoor intake port 55 is an opening provided in the building 2 that introduces outdoor air 49a (outdoor air) as outside air into the CO2 separation system 1. The outdoor air introduction duct 56 is a duct that introduces outside air into the housing 10. One end of the outdoor air introduction duct 56 is connected to the outdoor intake port 55, and outside air flows into the outdoor air introduction duct 56. The other end of the outdoor air introduction duct 56 is connected to the outdoor air inlet 43, and the outside air circulates within the housing 10. In other words, outdoor air is introduced into and circulates in the outdoor air introduction duct 56 as outside air.

[0015] The exhaust port 45 is an outlet that discharges air 49b from the CO2 separation system 1 to the outdoors. The exhaust port 45 is connected to an outdoor outlet 57 provided in the building 2 by an outdoor air discharge duct 58. The outdoor outlet 57 is an opening provided in the building 2 that discharges air 49b, whose CO2 concentration has increased due to the CO2 separation element 20, to the outdoors as EA. The outdoor air discharge duct 58 is a duct that supplies outside air from the housing 10 to the outdoors. One end of the outdoor air discharge duct 58 is connected to the exhaust port 45, and air 49b, whose CO2 concentration has increased due to the CO2 separation element 20, flows into the duct. The other end of the outdoor air discharge duct 58 is connected to the outdoor outlet 57, and the air 49b in the duct is discharged to the outdoors as EA. In other words, the outdoor air discharge duct 58 releases air 49b to the outdoors.

[0016] Hereafter, air 39a and air 39b may be collectively referred to as "internal air," and air 49a and air 49b may be collectively referred to as "external air." Additionally, the internal air intake duct 52 and internal air discharge duct 54 may be grouped together as an "internal air passage," and the external air intake duct 56 and external air discharge duct 58 may be grouped together as an "external air passage."

[0017] Here, we will describe the diameter of each duct. In this embodiment, the diameters of the outside air intake duct 56 and the outside air outlet duct 58, through which outside air flows, are smaller than the diameters of the inside air intake duct 52 and the inside air outlet duct 54, through which inside air flows. This is to make the flow rate of outside air circulating within the CO2 separation system 1 smaller than the flow rate of inside air. This makes it possible to suppress pressure loss on the outside air side. In addition, heat exchange generally occurs due to the temperature difference between outside air and inside air, but since the flow rate of outside air is suppressed, heat loss due to heat exchange can be suppressed.

[0018] A CO₂ separation element 20, an indoor air fan 31 (circulation fan), an indoor air filter 37, an outdoor air fan 41, and an outdoor air filter 47 are mounted inside the casing 10. The CO₂ separation element 20 separates CO₂ from the indoor air that has flowed through an indoor air introduction duct 52, and introduces the separated CO₂ into the outdoor air that has flowed through an outdoor air introduction duct 56. This can also be described as a member that selectively allows CO₂ to permeate from indoor air to outdoor air. Details of the CO₂ separation element 20 will be described later.

[0019] The indoor air fan 31 is a blower that sucks in indoor air from a target space through an indoor air port 33 and discharges the sucked indoor air into the target space through an air supply port 35. The indoor air sucked from the target space through the indoor air port 33 by driving the indoor air fan 31 passes through the indoor air filter 37, the CO₂ separation element 20, and the indoor air fan 31, and is discharged into the target space through the air supply port 35. It is preferable that the air volume delivered by the indoor air fan 31 is larger than the air volume delivered by the outdoor air fan 41. The indoor air filter 37 is a filter that removes dust and the like from the indoor air flowing into the casing 10 and supplies purified air to the CO₂ separation element 20, and is, for example, a HEPA (High Efficiency Particulate Air) filter or the like.

[0020] The outdoor air fan 41 is a blower that sucks outdoor air from the outdoors through the outdoor air port 43 and discharges it to the outdoors through the exhaust port 45. When the outdoor air fan 41 is driven, the outdoor air sucked from the outdoors through the outdoor air port 43 passes through the outdoor air filter 47, the CO2 separation element 20, and the outdoor air fan 41, and is discharged to the outdoors through the exhaust port 45. It is preferable that the air volume delivered by the outdoor air fan 41 is smaller than the air volume delivered by the indoor air fan 31. The outdoor air fan 41 is provided, for example, on the downstream side of the outdoor air filter 47 and on the upstream side of the CO2 separation element 20. With this arrangement, the outdoor air can be heated by the heat generated by the operation of the outdoor air fan 41, and when the outdoor air is at a lower temperature than the indoor air, the heat loss caused by heat exchange between the outdoor air and the indoor air is reduced. The outdoor air fan 41 may also be provided on the downstream side of the CO2 separation element 20. The outdoor air filter 47 is a filter that removes dust and dirt from the outdoor air flowing into the housing 10 and supplies purified air to the CO2 separation element 20, and is, for example, a HEPA filter or the like.

[0021] Here, an outline of CO2 separation by the CO2 separation element 20 will be described. FIGS. 2(a)-(b) show an outline of the CO2 separation element 20. FIG. 2(a) is a cross-sectional view showing a simplified configuration of the CO2 separation element 20. An indoor air passage 16 through which indoor air flows from left to right, and an outdoor air passage 17 through which outdoor air flows from left to right are arranged overlapping each other in the vertical direction. A CO2 separation membrane 22 is disposed between the indoor air passage 16 and the outdoor air passage 17. In the indoor air introduced into the indoor air passage 16, CO2 18 and N2 19 are mixed. Although actual air also contains O2 and the like, O2 and the like are omitted here for clarity of explanation. When indoor air flows along the CO2 separation membrane 22 in the indoor air passage 16, the CO2 separation membrane 22 selectively permeates CO2 18 in the indoor air and discharges CO2 18 to the outdoor air in the outdoor air passage 17. As a result, the concentration of CO2 18 in the indoor air decreases, while the concentration of CO2 18 in the outdoor air increases.

[0022] Figure 2(b) shows the configuration of the CO2 separation element 20 for more efficient CO218 separation than Figure 2(a). The CO2 separation element 20 includes the first internal air passage 16a to the third internal air passage 16c, collectively referred to as the internal air passage 16; the first external air passage 17a to the third internal air passage 16c, collectively referred to as the external air passage 17; and the first CO2 separation membrane 22a to the fifth CO2 separation membrane 22e, collectively referred to as the CO2 separation membrane 22. The number of internal air passages 16 and external air passages 17 is not limited to "3". From top to bottom, the first external air passage 17a, the first internal air passage 16a, the second external air passage 17b, the second internal air passage 16b, the third external air passage 17c, and the third internal air passage 16c are arranged in that order. Furthermore, a first CO2 separation membrane 22a is placed between the first outside air passage 17a and the first inside air passage 16a, a second CO2 separation membrane 22b is placed between the first inside air passage 16a and the second outside air passage 17b, and a third CO2 separation membrane 22c is placed between the second outside air passage 17b and the second inside air passage 16b. A fourth CO2 separation membrane 22d is placed between the second inside air passage 16b and the third outside air passage 17c, and a fifth CO2 separation membrane 22e is placed between the third outside air passage 17c and the third inside air passage 16c. Similar to Figure 2(a), the CO2 18 in the internal air flowing through the internal air passage 16 is selectively permeated through the CO2 separation membrane 22 and distributed to the outside air in the outside air passage 17.

[0023] Figure 3 shows the configuration of the CO2 separation element 20. This is a perspective view showing the laminated structure 6 used as the CO2 separation element 20 mounted on the CO2 separation system 1. In the following description, the stacking direction of the laminated structure 6 will be described as the vertical up-and-down direction, but this does not necessarily indicate the direction when the laminated structure 6 is mounted on the CO2 separation system 1. The laminated structure 6 is a structure in which rectangular frames 14 and rectangular CO2 separation element pieces 21 are alternately stacked in the vertical direction, and an internal air passage 16 and an external air passage 17 that intersects the internal air passage 16 are alternately stacked one layer at a time. More specifically, the laminated structure 6 is constructed by repeatedly stacking the CO2 separation element pieces 21 and the frame 14 while fitting the CO2 separation element pieces 21 to the ends of the frame 14 from both the upper and lower surfaces. When fitting the CO2 separation element pieces 21 to the frame 14 from both the upper and lower surfaces, the frames 14 are stacked orthogonally so that they are staggered one layer at a time. With this configuration, as shown in Figure 2(b), an internal air passage 16 through which internal air circulates and an external air passage 17 through which external air circulates are alternately formed, and the internal and external air flows alternately orthogonally through each air passage. As a result, the internal and external air flow alternately orthogonally in the stacking direction of the CO2 separation element piece 21, allowing the CO2 separation element 20 to selectively permeate CO2 from the internal air side to the external air side.

[0024] The CO2 separation element piece 21 is a sheet-like member that allows CO2 to pass from the internal air to the outside air when internal and external air flow with the CO2 separation element piece 21 in between. In this embodiment, the CO2 separation element piece 21 is fitted and bent by the frame 14, so it is preferable to use a member that has sufficient elasticity and strength to withstand this. The internal air passage 16 is an air passage through which the internal airflow circulates. More specifically, the internal air passage 16 is the air passage portion formed within the laminated structure 6 of the air passage through which air discharged from the target space to the outside flows. The external air passage 17 is an air passage through which the external airflow circulates. More specifically, the external air passage 17 is the air passage portion formed within the laminated structure 6 of the air passage through which air supplied from the outside to the target space flows. Return to Figure 1.

[0025] The first temperature control unit 4a is a device that adjusts the temperature of the outside air by heating or cooling the outside air flowing into the CO2 separation element 20. The first temperature control unit 4a is also called the outside air temperature control unit. The first temperature control unit 4a is, for example, a heater / Peltier element attached to the outside air intake duct 56. Alternatively, the first temperature control unit 4a may be an outside air fan 41 installed between the CO2 separation element 20 and the outside air passage. In this case, the outside air is heated using the exhaust heat from the outside air fan 41, so the exhaust heat from the outside air fan 41 is effectively utilized. The second temperature control unit 4b is a device that adjusts the temperature of the inside air by heating or cooling the inside air flowing into the CO2 separation element 20. The second temperature control unit 4b is also called the inside air temperature control unit. The second temperature control unit 4b is, for example, a heater / Peltier element attached to the inside air intake duct 52.

[0026] The outside air temperature detection unit 7 is attached to the outside air intake duct 56 and detects the temperature of the outside air flowing through the outside air intake duct 56. Since known techniques can be used for temperature detection, a detailed explanation is omitted here. Information regarding the outside air temperature detected by the outside air temperature detection unit 7 is transmitted to the control unit 5. The inside air temperature detection unit 8 detects the temperature of the inside air flowing through the inside air intake duct 52. Information regarding the inside air temperature detected by the inside air temperature detection unit 8 is transmitted to the control unit 5.

[0027] The control unit 5 receives the outside air temperature detected by the outside air temperature detection unit 7 and the inside air temperature detected by the inside air temperature detection unit 8. Based on the outside air temperature and the inside air temperature, the control unit 5 controls the temperature control unit 4. Specifically, the control unit 5 controls the first temperature control unit 4a so that the temperature difference between the temperature of the inside air introduced into the CO2 separation element 20 and the temperature of the outside air introduced into the CO2 separation element 20 is smaller than the temperature difference between the temperature of the air in the target space and the temperature of the outside air. This reduces the heat loss due to heat exchange in the CO2 separation element 20. For example, when the outside air is 5°C and the inside air is 25°C, if the temperature is not controlled, the air supplied to the target space by the inside air fan 31 will drop to about 15°C due to heat exchange, so extra air conditioning energy will be required to maintain the inside air at 25°C. On the other hand, if the temperature is controlled to set the outside air to 25°C, no heat exchange occurs, so the extra air conditioning energy is zero. Furthermore, if temperature control is performed using the exhaust heat from the outside fan 41, the energy required for temperature control becomes zero.

[0028] The subject of the apparatus, system, or method in this disclosure comprises a computer. The functions of the subject of the apparatus, system, or method in this disclosure are realized by the computer executing a program. The computer comprises a processor as its main hardware component, which operates according to the program. The processor is of any type as long as it can realize its functions by executing the program. The processor consists of one or more electronic circuits, including semiconductor integrated circuits (ICs) or LSIs (Large Scale Integrations). Multiple electronic circuits may be integrated on one chip or provided on multiple chips. Multiple chips may be aggregated in one device or provided on multiple devices. The program is recorded on a non-temporary recording medium such as a ROM, optical disc, or hard disk drive that is readable by the computer. The program may be pre-stored on the recording medium or supplied to the recording medium via a wide-area communication network, including the Internet.

[0029] Next, the operation of the CO2 separation system 1 will be explained. When the CO2 separation system 1 is started, the indoor fan 31 and the outdoor fan 41 start operating. The indoor fan 31 draws air 39a from the indoor intake port 51 into the housing 10 as RA through the indoor air introduction duct 52 and into the indoor air port 33. The incoming air 39a passes through the indoor air filter 37, removing dirt and dust, and becoming purified air. After that, the air 39a flows into the CO2 separation element 20.

[0030] Meanwhile, the outside air fan 41 draws air 49a from the outdoor intake port 55 into the enclosure 10 via the outside air introduction duct 56 and the outside air port 43. The incoming air 49b passes through the outside air filter 47, removing dust and debris, and becoming purified air. Subsequently, the air 49a flows into the CO2 separation element 20.

[0031] Air 39a flowing into the CO2 separation element 20 circulates through the internal air passage 16, while air 49a circulates through the external air passage 17. During this process, the CO2 separation membrane 22, which selectively permeates CO2, causes CO2 to move from the air 39a with a high CO2 concentration to the air 49a with a relatively low CO2 concentration. As a result, the CO2 concentration in air 39a decreases, becoming air 39b. Conversely, the CO2 concentration in air 49a increases, becoming air 49b.

[0032] The indoor air (air 39b) with a reduced CO2 concentration reaches the indoor outlet 53 via the indoor air discharge duct 54 from the air intake 35 and is supplied to the target space as SA. On the other hand, the outdoor air (air 49b) with an increased CO2 concentration reaches the outdoor outlet 57 via the outdoor air discharge duct 58 from the exhaust vent 45 and is discharged outdoors as EA. In this way, the CO2 separation system 1 releases CO2 from the indoor air to the outdoor air, suppressing the rise in CO2 concentration in the target space.

[0033] A limit may be defined for when the control unit 5 controls at least one of the ambient temperature and ambient temperature so that the temperature control energy required for the operation of at least one of the first temperature control unit 4a and the second temperature control unit 4b is less than the heat exchange energy resulting from the heat exchange between the ambient and ambient air in the CO2 separation membrane 22. Figure 4 shows the data structure of a table held by the control unit 5. The temperature difference and the maximum control amount are shown in correspondence. The temperature difference indicates the difference between the ambient temperature detected by the ambient temperature detection unit 7 and the ambient temperature detected by the ambient temperature detection unit 8. The maximum control amount indicates the maximum value when controlling at least one of the first temperature control unit 4a and the second temperature control unit 4b. The control unit 5 obtains the maximum control amount corresponding to the derived temperature difference by first deriving the temperature difference between the ambient temperature and the ambient temperature and then referring to the table in Figure 4. The control unit 5 controls at least one of the first temperature control unit 4a and the second temperature control unit 4b with a value smaller than the maximum control amount.

[0034] According to this embodiment, the temperature difference between the temperature of the indoor air introduced into the CO2 separation element 20 and the temperature of the outdoor air is controlled to be smaller than the temperature difference between the temperature of the air in the target space and the temperature of the outdoor air. Therefore, even when indoor and outdoor air are used to separate CO2, heat loss due to heat exchange can be reduced. Furthermore, since the temperature control is performed on the outdoor air so that its temperature approaches the temperature of the indoor air, the control can be simplified. In addition, since the temperature control energy required for the operation of the temperature control unit 4 is controlled to be smaller than the heat exchange energy caused by heat exchange between the indoor and outdoor air in the CO2 separation element 20, energy loss can be reduced. Furthermore, since the temperature control unit 4 is controlled based on the temperature of the indoor air detected by the indoor air temperature detection unit 8 and the temperature of the outdoor air detected by the outdoor air temperature detection unit 7, the accuracy of the control can be improved.

[0035] An outline of one aspect of the present disclosure is as follows: A CO2 separation system (1) in one aspect of the present disclosure includes: an indoor air passage (52, 16, 54) through which air from a target space indoors is introduced as indoor air, circulated, and returned to the target space; an outdoor air passage (56, 17, 58) through which outdoor air is introduced as outdoor air, circulated, and released to the outdoors; a CO2 separation unit (20) that separates CO2 from the indoor air circulating in the indoor air passage (16) and introduces it into the outdoor air circulating in the outdoor air passage (17); a temperature control unit (4) that adjusts at least one of the temperature of the indoor air introduced into the CO2 separation unit (20) and the temperature of the outdoor air introduced into the CO2 separation unit (20); and a control unit (5) that controls the temperature control unit (4). The control unit (5) controls the temperature control unit (4) so ​​that the temperature difference between the temperature of the indoor air introduced into the CO2 separation unit (20) and the temperature of the outdoor air introduced into the CO2 separation unit (20) is smaller than the temperature difference between the temperature of the air in the target space and the temperature of the outdoor air.

[0036] The control unit (5) may instruct the temperature control unit (4) to perform temperature control on the outside air so that the outside air temperature approaches the inside air temperature.

[0037] When the temperature control unit (4) is operating, the control unit (5) may control the temperature control unit (4) so ​​that the temperature control energy required for the operation of the temperature control unit (4) is less than the heat exchange energy resulting from the heat exchange between the internal and external air in the CO2 separation unit (20).

[0038] The system may further include an internal air temperature detection unit (7) for detecting the temperature of the internal air in the internal air passage (52), and an external air temperature detection unit (8) for detecting the temperature of the external air in the external air passage (56). The control unit (5) may control the temperature control unit (4) based on the internal air temperature detected by the internal air temperature detection unit (7) and the external air temperature detected by the external air temperature detection unit (8).

[0039] (Example 2) Next, we will describe Example 2. Example 2 relates to a CO2 separation system 1 similar to that in Example 1. In Example 2, in order to reduce the temperature difference between the indoor and outdoor air before temperature control is implemented, air from spaces other than the target space within the building 2 (hereinafter referred to as "additional air") is mixed with the outdoor air. Here, we will mainly explain the differences from Example 1.

[0040] Figure 5 shows the configuration of the CO2 separation system 1. In addition to the configuration shown in Figure 1, the CO2 separation system 1 includes an additional duct 60 and a damper 62. The additional duct 60, also called an additional air passage, opens outside the target space inside the building 2 (for example, in the attic). The additional duct 60 is connected to the outside air intake duct 56 upstream of the CO2 separation element 20. The additional duct 60 circulates additional air into the outside air intake duct 56, thereby performing heat exchange between the additional air flowing into the outside air intake duct 56 and the outside air. If the temperature of the additional air is closer to the temperature of the indoor air than the temperature of the outside air, the heat exchange between the additional air and the outside air will cause the temperature of the mixed air (outside air and additional air) to be closer to the temperature of the indoor air than the temperature of the outside air. A damper 62 is provided at the point where the additional duct 60 connects to the outside air intake duct 56. The opening and closing of the damper 62 is controlled by the control unit 5. By controlling the opening and closing of the damper 62, the amount of additional air flowing from the additional duct 60 into the outside air intake duct 56 is controlled.

[0041] In this embodiment, by connecting the additional duct 60 to the outside air intake duct 56 upstream of the CO2 separation element 20, heat exchange is performed between the additional air flowing into the outside air intake duct 56 and the outside air, thereby bringing the temperature of the mixed air of outside air and additional air closer to the temperature of the inside air. Furthermore, since the temperature of the mixed air of outside air and additional air is brought closer to the temperature of the inside air, thermal loss due to heat exchange can be reduced.

[0042] An outline of one aspect of this disclosure is as follows: The system may further include an additional air passage (60) through which air from outside the target space indoors flows as additional air. The additional air passage (60) is connected to an outside air passage (56) upstream of the CO2 separation unit (20), and the additional air passage (60) may perform heat exchange between the additional air flowing into the outside air passage (56) and the outside air by circulating the additional air into the outside air passage (56).

[0043] The present disclosure has been explained above with reference to examples. These examples are illustrative, and it will be understood by those skilled in the art that various modifications are possible for each component or combination of processing steps, and that such modifications are also within the scope of the present disclosure.

[0044] In Example 1, the system was configured to introduce outdoor (outside the building) air as air 49a, but it is not limited to this. For example, the system may be configured to introduce air from the ceiling inside the building as air 49a, or to introduce indoor air from an adjacent room where no people are present. In this way, air with a lower carbon dioxide concentration than the air 39a in the target space where people are present and the carbon dioxide concentration has risen can be introduced into the CO2 separation element 20 as air 49a. Therefore, the same effect can be enjoyed in which CO2 moves from the air 39a with a high CO2 concentration to the air 49a with a relatively low CO2 concentration, thereby suppressing the rise in CO2 concentration in the target space. [Explanation of Symbols]

[0045] 1 CO2 separation system, 2 Building, 4 Temperature control unit, 5 Control unit, 6 Laminated structure, 7 Outside air temperature detection unit, 8 Inside air temperature detection unit, 10 Housing, 14 Frame, 16 Inside air passage, 17 Outside air passage, 18 CO2, 19 N2, 20 CO2 separation element, 21 CO2 separation element piece, 22 CO2 separation membrane, 31 Inside fan, 33 Inside air vent, 35 Intake vent, 37 Inside air filter, 39 Air, 41 Outside fan, 43 Outside air vent, 45 Exhaust vent, 47 Outside air filter, 49 Air, 51 Indoor intake, 52 Inside air introduction duct, 53 Indoor outlet, 54 Inside air discharge duct, 55 Outdoor intake, 56 57 Outdoor air intake duct, 58 Outdoor air outlet duct.

Claims

1. An indoor air passage through which air from a target space is introduced as indoor air, circulated, and returned to the target space, An outside air passage through which outdoor air is introduced as outside air, circulated, and released to the outside, CO2 is released from the recirculating recirculating air through the recirculating air passage. ２ CO2 is separated and introduced into the outside air flowing through the outside air passage. ２ Separation section and The aforementioned CO ２ The temperature of the internal air introduced into the separation unit, and the CO ２ A temperature control unit that adjusts at least one of the temperatures of the outside air introduced into the separation unit, A control unit that controls the temperature control unit, Equipped with, The control unit is the CO ２ The temperature of the internal air introduced into the separation unit, and the CO ２ The temperature control unit is controlled such that the temperature difference between the temperature of the outside air introduced into the separation unit and the temperature of the outside air is smaller than the temperature difference between the temperature of the air in the target space and the temperature of the outside air. CO ２ Separation system.

2. The control unit causes the temperature control unit to perform temperature control on the outside air so that the temperature of the outside air approaches the temperature of the inside air, according to claim 1 of the CO2 ２ Separation system.

3. When the temperature control unit is operating, The control unit, The temperature adjustment energy required for the operation of said temperature adjustment unit is less than the heat exchange energy resulting from the heat exchange of said indoor air and said outdoor air in the CO ２ separation unit, wherein said temperature adjustment unit is controlled accordingly. The CO according to claim 1 ２ separation system.

4. An internal air temperature detection unit that detects the temperature of the internal air in the internal air passage, The system further includes an outside air temperature detection unit that detects the temperature of the outside air in the outside air passage, The control unit controls the temperature control unit based on the temperature of the indoor air detected by the indoor air temperature detection unit and the temperature of the outdoor air detected by the outdoor air temperature detection unit, according to claim 1 of the CO2 control unit. ２ Separation system.

5. The indoors further comprises an additional air passage through which air from outside the target space flows as additional air, The aforementioned additional air passage is the CO ２ Upstream of the separation section, it is connected to the outside air passage. The CO2 according to claim 1, wherein the additional air passage allows the additional air to flow into the outside air passage, thereby performing heat exchange between the additional air flowing into the outside air passage and the outside air. ２ Separation system.

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