CO2 separation system

Abstract

A CO2 separation system (1) is provided with a CO2 separation element (20), a CO2 detection unit (8), an internal air fan (31), an external air fan (41), and a control unit (5). A CO2 separation element (20) separates carbon dioxide (CO2) from air (39a) in a target space (2) in a room and discharges the carbon dioxide to the outside of the room. The CO2 detection unit (8) detects the CO2 concentration in the target space (2). The internal air fan (31) and the external air fan (41) supply air to the CO2 separation element (20). The control unit (5) controls the internal air fan (31) and the external air fan (41), and determines the amount of air supplied to the CO2 separation element (20) by the internal air fan (31) and the external air fan (41) so as to achieve CO2 separation efficiency determined on the basis of the CO2 concentration detected by the CO2 detection unit (8).

Description

Technical Field

[0001] This invention relates to a CO2 separation system for separating CO2 from air in an object space. Background Art

[0002] Conventionally, CO2 separation systems are known to reduce the concentration of carbon dioxide (CO2) in the air of an enclosed object space (e.g., Patent Document 1). These CO2 separation systems have modules (CO2 separation elements) that preferentially separate CO2. When air from the object space is supplied to the CO2 separation system, the CO2 contained in that air is preferentially separated and released within the module, thus reducing the amount of CO2 remaining in the air. By returning this remaining air to the object space, the CO2 separation system can further reduce the concentration of CO2 in the object space.

[0003] In a CO2 separation system, the CO2 separation efficiency, which is an indicator of the performance of CO2 separation of the CO2 separation element, is defined by the following equation (1).

[0004] [Mathematical Expression 1]

[0005]

[0006] On the other hand, as a method to reduce the concentration of CO2 in the object space, a method is generally used to release the air (internal gas) of the object space inside the room to the outside at a certain flow rate (exhaust) and to take in an equal amount of air (external gas) from outside the object space (hereinafter referred to as "normal ventilation").

[0007] Here, refer to Figure 9A A comparison was made between a CO2 separation system that reduces the CO2 concentration in the target space and a conventional ventilation system. Figure 9A This is a graph showing the amount of CO2 removed per unit time and the power consumption required to remove that amount of CO2 for both CO2 separation systems and general ventilation. Figure 9A The vertical axis represents electricity consumption, and the horizontal axis represents CO2 removal per unit time. Additionally, Figure 9A Solid lines represent CO2 separation systems, and dashed lines represent normal ventilation.

[0008] When a CO2 separation system is to release a specified amount of CO2 outside per unit time, air needs to be drawn into the CO2 separation system at a rate greater than the normal ventilation rate, depending on the CO2 separation efficiency of the CO2 separation element.

[0009] However, as Figure 9AAs shown, if the CO2 removal rate per unit time is set below a specified range, the CO2 separation device has the advantage of significantly reducing power consumption compared to conventional ventilation. Conventional ventilation, because it draws in external gas, requires air conditioning of the target space based on the external gas temperature, resulting in significant power consumption for this air conditioning. In contrast, the CO2 separation device reduces the heat transfer from the internal gas to the external gas, thus minimizing the air conditioning burden. Therefore, from an energy-saving perspective, the CO2 separation system is advantageous as a system for reducing the CO2 concentration in the target space.

[0010] Existing technical documents

[0011] Patent Literature

[0012] Patent Document 1: Japanese Patent Publication No. 2006-512946 Summary of the Invention

[0013] Additionally, consider a method to increase the airflow rate (internal gas flow rate) of the air drawn from the object space into the CO2 separation system when the CO2 concentration in the object space is high. Here, refer to... Figure 9B The relationship between the internal gas supply volume and the CO2 separation efficiency mentioned above is explained. Figure 9B This is a graph showing the parameter dependence of the CO2 separation efficiency of the CO2 separation system.

[0014] Figure 9B The vertical axis represents the CO2 separation efficiency of the CO2 separation system, and the horizontal axis represents the value of the parameter shown in equation (2) below. Figure 9B The relationship between the values ​​of the parameters shown in equation (2) and the CO2 separation efficiency of the CO2 separation system is shown.

[0015] K / F×P·M / ρ…(2)

[0016] Here, K is the separation coefficient, and F is the internal gas supply volume (m³ / s). 3 / s), P is atmospheric pressure [kPa], M is the molecular weight of CO2 [g / mol], ρ is the density of CO2 [g / m³]. 3 ].in addition, Figure 9B Set the ratio of feed air volume to sweep air volume to 1:1.

[0017] As in equation (2), in Figure 9B In the parameters shown, the internal gas supply volume is in the denominator. Therefore, according to Figure 9BIt is known that the higher the internal gas supply volume, the lower the CO2 separation efficiency. This is believed to be because when the internal gas supply volume increases, the amount of CO2 returning to the object space increases before the air taken in from the object space is separated by the CO2 separation element.

[0018] Therefore, when a CO2 separation system aims to increase the CO2 removal rate per unit time, even increasing the internal gas flow rate will only result in a small increase in CO2 removal. Figure 9A As shown, the rate of increase in power consumption increases with the increase in CO2 removal per unit time. Furthermore, if the CO2 removal rate per unit time of the CO2 separation system is set to exceed a predetermined level, the power consumption is actually higher than that of normal ventilation. Therefore, CO2 separation systems require control for the efficient removal of CO2 from the target space.

[0019] The present invention was made in view of the above circumstances, and provides a CO2 separation system capable of efficiently removing CO2 from an object space.

[0020] To achieve this objective, a CO2 separation system according to a certain embodiment of the present invention includes a CO2 separation unit, a CO2 detection unit, an air supply unit, and a control unit. The CO2 separation unit separates carbon dioxide (CO2) from the air in the target space inside the building and releases it outside. The CO2 detection unit detects the CO2 concentration in the target space. The air supply unit supplies air to the CO2 separation unit. The control unit controls the air supply unit and determines the air volume supplied from the air supply unit to the CO2 separation unit in a manner that determines the CO2 separation efficiency based on the CO2 concentration detected by the CO2 detection unit.

[0021] The CO2 separation system according to the present invention can efficiently remove CO2 from the target space. Attached Figure Description

[0022] Figure 1 This is a schematic diagram illustrating an example of the setup of a CO2 separation system according to the first embodiment of the present invention.

[0023] Figure 2A This is a cross-sectional view showing a simplified structure of the CO2 separation element mounted on the CO2 separation system.

[0024] Figure 2B It shows that it will be used for comparison Figure 2A A simplified cross-sectional view of a CO2 separation element that efficiently performs CO2 separation.

[0025] Figure 3 This is a perspective view showing a stacked structure used as a CO2 separation element mounted in the CO2 separation system.

[0026] Figure 4This is a graph used to illustrate the CO2 separation efficiency determined by the control unit of the CO2 separation system based on the CO2 concentration in the object space.

[0027] Figure 5A This is a diagram showing an example of the internal gas flow rate of the internal gas fan and the external gas flow rate of the external gas fan, determined by the CO2 separation efficiency determined by the control unit (the internal gas flow rate and the external gas flow rate are "1:1").

[0028] Figure 5B This is a graph showing an example of the internal gas flow rate of the internal gas fan and the external gas flow rate of the external gas fan, determined by the CO2 separation efficiency specified by the control unit (the ratio of internal gas flow rate to external gas flow rate varies).

[0029] Figure 5C This is a diagram showing an example of the internal gas flow rate of the internal gas fan and the external gas flow rate of the external gas fan, determined for the CO2 separation efficiency determined by the control unit (the case where the internal gas flow rate is adjusted relative to the determined CO2 separation efficiency while keeping the external gas flow rate fixed).

[0030] Figure 6 This is a flowchart illustrating a portion of the air supply control process performed by the control unit.

[0031] Figure 7 This shows the control process of the air supply unit. Figure 6 The subsequent flowchart.

[0032] Figure 8A This is a diagram illustrating the power consumption determined by the control unit of the CO2 separation system according to the CO2 concentration in the target space in the second embodiment of the present invention.

[0033] Figure 8B This is a diagram showing an example of the internal air volume of the internal gas fan and the external air volume of the external gas fan, which are determined by the control unit based on the power consumption.

[0034] Figure 9A This is a graph showing the amount of CO2 removed per unit time and the power consumption required to remove that amount of CO2 for both CO2 separation systems and general ventilation.

[0035] Figure 9B This is a graph showing the parameter dependence of the CO2 separation efficiency of the CO2 separation system. Detailed Implementation

[0036] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that the embodiments described below are all preferred examples of the present invention. Therefore, the numerical values, shapes, materials, constituent elements, and the arrangement and connection methods of the constituent elements shown in the following embodiments are examples and are not intended to limit the present invention. Therefore, constituent elements not described in the independent technical solutions representing the highest concept of the present invention in the constituent elements of the following embodiments will be described as arbitrary constituent elements. Furthermore, in the figures, substantially identical structures are labeled with the same reference numerals, and repeated descriptions are omitted or simplified.

[0037] (First Implementation)

[0038] First, refer to Figure 1 The general structure of the CO2 separation system 1 according to the first embodiment of the present invention will be described. Figure 1 This is a schematic diagram showing an example of the installation of CO2 separation system 1. CO2 separation system 1 is a system installed inside a building such as a residence, which separates a target gas (such as carbon dioxide (CO2)) from the air 39a in the target space 2 inside the building and releases it outside.

[0039] The CO2 separation system 1 includes a housing 10, a CO2 separation element 20, an internal gas air passage 16, an internal gas fan 31, an internal gas filter 37, an external gas air passage 17, an external gas fan 41, an external gas filter 47, a control unit 5, and a CO2 detection unit 8.

[0040] The housing 10 is the outer frame of the CO2 separation system 1. The internal gas flow path 16 and the external gas flow path 17 are formed independently, dividing the internal space formed inside the housing 10. Furthermore, the CO2 separation element 20 is an element disposed inside the housing 10 within the range of the internal gas flow path 16 and the external gas flow path 17, separating CO2 from the air 39a flowing through the internal gas flow path 16 and releasing the separated CO2 to the air 49a flowing through the external gas flow path 17. This CO2 separation element 20 corresponds to an example of the CO2 separation section of the present invention. For details regarding the CO2 separation element 20, refer to... Figure 2A , Figure 2B as well as Figure 3 Then it will be discussed.

[0041] The internal gas duct 16 is a duct that allows air 39a, which is the target space 2 for CO2 removal, to be introduced and circulated, and allows air 39b, obtained by reducing the CO2 concentration from air 39a under the action of CO2 separation element 20, to flow back to the target space 2. In the following description, air 39a and air 39b will be collectively referred to as "internal gas".

[0042] External gas duct 17 is a duct that allows outdoor air 49a to be introduced and circulated, and allows air 49b, whose CO2 concentration has increased relative to air 49a due to CO2 separation element 20, to be released outside. In the following description, air 49a and air 49b will be collectively referred to as "external gas".

[0043] An internal gas inlet 33, an air supply inlet 35, an external gas inlet 43, and an exhaust inlet 45 are arranged on the outer periphery of the housing 10. The internal gas inlet 33 is an intake port that draws in the air 39a of the object space 2 inside the room as internal gas into the internal gas air passage 16 of the CO2 separation system 1. The internal gas inlet 33 is connected to the indoor intake port 51 through an internal gas introduction pipe 52.

[0044] The indoor intake vent 51 is an opening in the object space 2 within the room, drawing in air 39a from the object space 2 as RA (Return Air). The internal gas inlet duct 52 is a conduit that guides the air 39a from the object space 2 drawn in through the indoor intake vent 51 to the internal gas outlet 33. One end of the internal gas inlet duct 52 is connected to the indoor intake vent 51, and the air 39a from the object space 2 flows into the internal gas inlet duct 52 as RA. The other end of the internal gas inlet duct 52 is connected to the internal gas outlet 33, allowing RA to flow into the internal gas airflow path 16. In other words, the internal gas inlet duct 52 introduces and circulates the air 39a from the object space 2 within the room as internal gas into the internal gas airflow path 16.

[0045] The air supply port 35 is the outlet from which air 39b, which is internal gas with reduced CO2 concentration due to the action of the CO2 separation element 20, is discharged from the CO2 separation system 1. The air supply port 35 is connected to the indoor air outlet 53 through the internal gas outlet pipe 54.

[0046] The indoor air outlet 53 is an opening in the target space 2 located inside the room, supplying air 39b with reduced CO2 concentration as SA (Supply Air) to the target space 2. The internal gas outlet duct 54 is a conduit that guides the air 39b blown from the CO2 separation system 1 to the indoor air outlet 53. One end of the internal gas outlet duct 54 is connected to the air supply port 35, and under the action of the CO2 separation element 20, the air 39b with reduced CO2 concentration flows into the internal gas outlet duct 54. The other end of the internal gas outlet duct 54 is connected to the indoor air outlet 53, supplying the air 39b within the internal gas outlet duct 54 as SA to the target space 2. In other words, the internal gas outlet duct 54 causes the air 39b to flow back into the target space 2.

[0047] External gas inlet 43 is an intake port that draws in outdoor air 49a as external gas into the external gas duct 17 of the CO2 separation system 1. External gas inlet 43 is connected to outdoor intake port 55 through external gas inlet pipe 56.

[0048] The outdoor intake vent 55 is an opening located on the exterior wall of the building, drawing in outdoor air 49a as OA (Outside Air). The external air inlet duct 56 is a conduit that guides the air 49a drawn in from the outdoor intake vent 55 to the external air outlet 43. One end of the external air inlet duct 56 is connected to the outdoor intake vent 55, allowing outdoor air 49a to flow into the external air inlet duct 56 as OA. The other end of the external air inlet duct 56 is connected to the external air outlet 43, allowing OA to flow into the external air passage 17. In other words, the external air inlet duct 56 guides and circulates outdoor air 49a as external air into the external air passage 17.

[0049] Exhaust port 45 is the outlet from which air 49b, which is external gas that has risen due to the action of CO2 separation element 20, is discharged from CO2 separation system 1. Exhaust port 45 is connected to outdoor outlet 57 through external gas outlet pipe 58.

[0050] The outdoor exhaust outlet 57 is an opening located on the exterior wall of the building, which discharges the air 49b with increased CO2 concentration as EA (Exhaust Air) to the outside. The external gas exhaust duct 58 is a duct that guides the air 49b blown from the CO2 separation system 1 to the outdoor exhaust outlet 57. One end of the external gas exhaust duct 58 is connected to the exhaust port 45, and the air 49b with increased CO2 concentration flows into the external gas exhaust duct 58 under the action of the CO2 separation element 20. The other end of the external gas exhaust duct 58 is connected to the outdoor exhaust outlet 57, and the air 49b within the external gas exhaust duct 58 is discharged to the outside as EA. In other words, the external gas exhaust duct 58 releases air 49b to the outside.

[0051] It should be noted that the internal gas inlet pipe 52 and the internal gas outlet pipe 54 can also be combined with the internal gas air path 16 to form the "internal gas air path", and the external gas inlet pipe 56 and the external gas outlet pipe 58 can also be combined with the external gas air path 17 to form the "external gas air path".

[0052] The internal gas fan 31 is a blower that is installed, for example, downstream of the CO2 separation element 20 in the internal gas air passage 16, and draws internal gas from the target space 2 through the internal gas port 33 and discharges it into the target space 2 through the air supply port 35, thereby supplying air to the internal gas passage 16. The internal gas fan 31 is a specific example of the air supply unit of the present invention.

[0053] Internal gas drawn in from the object space 2 via internal gas port 33 by driving internal gas fan 31 is sent to CO2 separation element 20 via internal gas filter 37, and further discharged to the object space 2 via air supply port 35.

[0054] It should be noted that the internal gas fan 31 can also be installed on the upstream side of the CO2 separation element 20, and further, it can be installed on the downstream side of the internal gas filter 37 and the upstream side of the CO2 separation element 20.

[0055] The internal gas filter 37 is a filter that removes debris and dust from the internal gas flowing into the housing 10 and supplies the cleaned air 39a to the CO2 separation element 20. The internal gas filter 37 may be, for example, a HEPA (High Efficiency Particulate Air) filter.

[0056] The external gas fan 41 is a blower installed in the external gas duct 17, which draws in external gas from outside through the external gas inlet 43 and discharges it to the outside through the exhaust outlet 45, thereby supplying external gas to the external gas duct 17. The external gas fan 41 is a specific example of the air supply unit of the present invention.

[0057] External air drawn in from outside through external air inlet 43 by driving external air fan 41 is sent to CO2 separation element 20 through external air filter 47 and further discharged outside through exhaust port 45.

[0058] An external gas fan 41 is installed, for example, upstream of the CO2 separation element 20, preferably downstream of the external gas filter 47 and upstream of the CO2 separation element 20. This configuration allows the external gas to be heated using the heat generated by the operation of the external gas fan 41, reducing heat loss due to heat exchange between the external and internal gases when the external gas is colder than the internal gas. However, the external gas fan 41 can also be installed downstream of the CO2 separation element 20.

[0059] The external gas filter 47 is a filter that removes debris and dust from the external gas flowing into the housing 10 and supplies the cleaned air 49a to the CO2 separation element 20, such as using a HEPA filter.

[0060] Here, refer to Figure 2A , Figure 2B as well as Figure 3 A summary of the CO2 separation performed by the CO2 separation element 20 will be provided. First, Figure 2A This is a cross-sectional view showing a simplified structure of the CO2 separation element 20. Figure 2A In the diagram, the internal gas passage 16, which allows internal gas to flow from left to right, and the external gas passage 17, which allows external gas to flow from left to right, are arranged overlapping in the vertical direction.

[0061] The CO2 separation element 20 has a CO2 separation membrane 22 disposed between the internal gas flow path 16 and the external gas flow path 17. The internal gas introduced into the internal gas flow path 16 contains carbon dioxide (CO2) 18 and nitrogen (N2) 19. In actual air, oxygen (O2) and the like are also mixed in, but O2 and the like are omitted here for clarity.

[0062] When the internal gas flows along the CO2 separation membrane 22 within the internal gas airflow path 16, the CO2 separation membrane 22 selectively separates (permeates) CO2 18 in the internal gas and releases CO2 18 into the external gas airflow path 17. As a result, the concentration of CO2 18 in the internal gas decreases, and the concentration of CO2 18 in the external gas increases.

[0063] Figure 2B It shows that it will be used for comparison Figure 2A A simplified cross-sectional view of the CO2 separation element 20, which efficiently performs CO2 separation. Figure 2B The CO2 separation element 20 shown includes a first internal gas airway 16a to a third internal gas airway 16c collectively referred to as internal gas airways 16, a first external gas airway 17a to a third external gas airway 17c collectively referred to as external gas airways 17, and a first CO2 separation membrane 22a to a fifth CO2 separation membrane 22e collectively referred to as CO2 separation membrane 22. It should be noted that the number of internal gas airways 16 and external gas airways 17 is not limited to "3".

[0064] exist Figure 2B In the middle, the first external gas air passage 17a, the first internal gas air passage 16a, the second external gas air passage 17b, the second internal gas air passage 16b, the third external gas air passage 17c, and the third internal gas air passage 16c are arranged sequentially from the top to the bottom.

[0065] Furthermore, a first CO2 separation membrane 22a is disposed between the first external gas flow path 17a and the first internal gas flow path 16a. A second CO2 separation membrane 22b is disposed between the first internal gas flow path 16a and the second external gas flow path 17b. A third CO2 separation membrane 22c is disposed between the second external gas flow path 17b and the second internal gas flow path 16b. A fourth CO2 separation membrane 22d is disposed between the second internal gas flow path 16b and the third external gas flow path 17c. A fifth CO2 separation membrane 22e is disposed between the third external gas flow path 17c and the third internal gas flow path 16c.

[0066] and Figure 2A Similarly, the CO2 18 of the internal gas flowing in the internal gas passage 16 is selectively separated (permeated) in the CO2 separation membrane 22 and released into the external gas passage 17.

[0067] Figure 3 This is a perspective view showing a stacked structure 6 used as a CO2 separation element 20 mounted in a CO2 separation system 1. Hereinafter, the stacking direction of the stacked structure 6 will be described as the vertical direction, but it does not necessarily represent the direction of the stacked structure 6 when mounted in the CO2 separation system 1.

[0068] The stacked structure 6 is a structure in which a rectangular frame 14 and a rectangular CO2 separation element 21 composed of a CO2 separation membrane 22 are alternately stacked in the vertical direction, thereby alternating the internal gas air passage 16 and the external gas air passage 17 that intersects with the internal gas air passage 16.

[0069] More specifically, the stacked structure 6 is constructed by repeatedly stacking the CO2 separating element portion 21 with the frame 14 while fitting the CO2 separating element portion 21 from both the top and bottom sides at the ends of the frame 14.

[0070] When the CO2 separating element 21 is fitted into the frame 14 from both the top and bottom, the frame 14 is orthogonally stacked in a staggered manner. By adopting this structure, as... Figure 2B As shown, an internal gas ventilation path 16 for ventilating internal gases and an external gas ventilation path 17 for ventilating external gases are alternately formed. Furthermore, air 39a drawn in from the object space 2 circulates in the internal gas ventilation path 16, and air 49a drawn in from outside circulates in the external gas ventilation path 17, so that the internal gas flow and the external gas flow alternate and orthogonally in each ventilation path.

[0071] Thus, the stacked structure 6 allows the internal and external gases to flow alternately and orthogonally in the stacking direction of the CO2 separation element section 21. As a result, the CO2 separation element 20 allows CO2 to selectively permeate from the internal gas side to the external gas side via the CO2 separation membrane 22 of the CO2 separation element section 21.

[0072] The CO2 separation element portion 21 is a sheet-like component consisting of a CO2 separation membrane 22 that allows CO2 to pass through from the internal gas to the external gas when the internal gas and the external gas flow through the CO2 separation element portion 21. The CO2 separation element portion 21 is fitted and bent by the frame 14, so it is preferable to use a component with elasticity and strength that can withstand this situation.

[0073] return Figure 1 The description of CO2 separation system 1 will continue. A CO2 detection unit 8 is installed in the internal gas inlet pipe 52 and detects the CO2 concentration in the air 39a flowing through the internal gas inlet pipe 52. The air 39a flowing through the internal gas inlet pipe 52 is air drawn in from the target space 2. Therefore, the CO2 concentration detected by the CO2 detection unit 8 corresponds to the CO2 concentration within the target space 2.

[0074] Information related to the CO2 concentration within the object space 2 detected by the CO2 detection unit 8 is sent to the control unit 5. It should be noted that the CO2 detection unit 8 can also be directly installed in the object space 2 to detect the CO2 concentration within the object space 2 and send the detected CO2 concentration within the object space 2 to the control unit 5.

[0075] The control unit 5 controls the internal gas fan 31 and the external gas fan 41. Specifically, the control unit 5 determines the CO2 separation efficiency of the CO2 separation element 20, which is used to reduce the CO2 concentration from the object space 2 having that CO2 concentration, based on the CO2 concentration detected by the detection unit 8. The control unit 5 determines the air volume (internal gas supply volume) of the internal gas fan 31 and the air volume (external gas supply volume) of the external gas fan 41 in a manner that becomes the determined CO2 separation efficiency. Furthermore, the control unit 5 controls the internal gas fan 31 in a manner that becomes the determined internal gas supply volume, and controls the external gas fan 41 in a manner that becomes the determined external gas supply volume.

[0076] Here, refer to Figure 4 as well as Figures 5A to 5C This section describes an example of a control method in which the control unit 5 controls the internal gas flow rate of the internal gas fan 31 and the external gas flow rate of the external gas fan 41 based on the CO2 separation efficiency. Figure 4 It is used to explain the use of control unit 5 Figure 9AThe graph shown is a graph of CO2 separation efficiency determined based on the CO2 concentration in object space 2.

[0077] Control unit 5, etc. Figure 4 As shown, for example, the CO2 separation efficiency of a CO2 separation element 20 is determined from three options—CO2 separation efficiency A, CO2 separation efficiency B, and CO2 separation efficiency C—based on the CO2 concentration within the object space 2. That is, when the CO2 concentration within the object space 2 is high, a CO2 separation efficiency with a higher CO2 removal rate per unit time is determined. Conversely, when the CO2 concentration within the object space 2 is low, a CO2 separation efficiency with a lower CO2 removal rate per unit time is determined.

[0078] CO2 separation efficiencies A, B, and C are preset during the design phase of CO2 separation system 1. For example, CO2 separation efficiency B is set to 20%, and CO2 separation efficiency C is set to 40%. Furthermore, CO2 separation efficiency A is set to the same CO2 separation efficiency as conventional ventilation systems with equivalent power consumption (CO2 removal rate per unit time). Figure 4 In the example shown, it is set to 18%.

[0079] Here, CO2 separation efficiencies B and C are set to be higher than CO2 separation efficiency A. (Refer to the above...) Figure 9A as well as Figure 9B In the CO2 separation system 1, the higher the CO2 separation efficiency, the smaller the required internal gas flow rate is, thus suppressing power consumption. The control unit 5 sets the CO2 separation efficiency of the CO2 separation element 20 to be A or higher, thereby enabling the CO2 separation system 1 to achieve energy savings compared to conventional ventilation.

[0080] It should be noted that the CO2 separation efficiency A to CO2 separation efficiency C are appropriately set according to the characteristics of the CO2 separation element 20, and are not limited to the values ​​mentioned above.

[0081] The relationship between CO2 separation efficiency and CO2 concentration in target space 2 is determined during the design phase of CO2 separation system 1 as follows. First, the amount of CO2 removed per unit time at CO2 separation efficiency B is determined as "the amount of CO2 that can maintain a baseline concentration of 1000 ppm when there are N people in target space 2".

[0082] Therefore, the membrane size of the CO2 separation membrane 22 of the CO2 separation element 20 is also determined during the design phase of the CO2 separation system 1. Furthermore, the CO2 concentration within the target space 2, from CO2 separation efficiency C to CO2 separation efficiency B, is also determined. Figure 7The fourth concentration in step S12 of the flowchart described later is determined to be 1000 ppm. Additionally, the CO2 concentration in the target space 2 where the CO2 separation efficiency is switched from A to B (…) Figure 6 The first concentration in step S3 of the flowchart described later is determined to be 1000 ppm.

[0083] On the other hand, the CO2 concentration in object space 2 where the CO2 separation efficiency is switched from B to C ( Figure 7 The second concentration in step S8 of the flowchart described later can also be determined to be 1000 ppm. However, if the CO2 concentration in the target space 2 when switching from CO2 separation efficiency C to CO2 separation efficiency B and the CO2 concentration in the target space 2 when switching from CO2 separation efficiency B to CO2 separation efficiency C are both set to the same 1000 ppm, the following problem may occur. That is, if the CO2 concentration in the target space 2 is around 1000 ppm, the CO2 separation efficiency determined by the control unit 5 may frequently switch between CO2 separation efficiency B and CO2 separation efficiency C.

[0084] Therefore, the CO2 concentration in object space 2 where the CO2 separation efficiency changes from B to C ( Figure 7 The second concentration of step S8 in the flowchart shown below can also be determined according to the following equation (3).

[0085] [Mathematical formula 2]

[0086]

[0087] Here, the internal gas supply volume B is the internal gas supply volume of the internal gas fan 31 determined by the CO2 separation element 20 achieving a CO2 separation efficiency B. Similarly, the internal gas supply volume C is the internal gas supply volume of the internal gas fan 31 determined by the CO2 separation element 20 achieving a CO2 separation efficiency C. Furthermore, the external gas concentration is the CO2 concentration in the external gas, for example, 400 ppm.

[0088] Additionally, the CO2 concentration within object space 2 where the CO2 separation efficiency is switched from B to A ( Figure 7 The third concentration in step S10 of the flowchart shown below is, for example, determined to be 1200 ppm.

[0089] The control unit 5 compares the first to fourth concentrations determined as described above with the CO2 concentration in the target space 2 to determine the CO2 separation efficiency of the CO2 separation element 20 from CO2 separation efficiency A to CO2 separation efficiency C. Furthermore, the control unit 5 determines the internal gas flow rate of the internal gas fan 31 and the external gas flow rate of the external gas fan 41 in a manner consistent with the determined CO2 separation efficiency, and controls the internal gas fan 31 and the external gas fan 41 in a manner consistent with the determined internal and external gas flow rates.

[0090] Figures 5A to 5C This is a diagram illustrating an example of the internal gas flow rate of the internal gas fan 31 and the external gas flow rate of the external gas fan 41, determined by the CO2 separation efficiency specified by the control unit 5. For example, Figure 5A This example illustrates how control unit 5 determines the internal and external gas flow rates in a 1:1 ratio between the internal gas flow rate of internal gas fan 31 and the external gas flow rate of external gas fan 41. In this example, control unit 5 sets both the internal and external gas flow rates to 1000 L / min for a CO2 separation efficiency C (40%). Furthermore, control unit 5 sets both the internal and external gas flow rates to 3000 L / min for a CO2 separation efficiency B (20%). Additionally, control unit 5 sets both the internal and external gas flow rates to 4000 L / min for a CO2 separation efficiency A (18%).

[0091] It should be noted that, in this example, the CO2 concentration in object space 2 during the switch from CO2 separation efficiency B (20%) to CO2 separation efficiency C (40%) is... Figure 7 The second concentration in step S8 of the flowchart described later can also be set to 800 ppm using the above formula (3).

[0092] The control unit 5 does not need to fix the ratio of the internal gas flow rate of the internal gas fan 31 to the external gas flow rate of the external gas fan 41, which is determined for the CO2 separation efficiency, to "1:1", or it can be fixed to another ratio (e.g., "2:1").

[0093] In addition, if Figure 5BAs shown, the control unit 5 can also change the ratio of the internal airflow of the internal gas fan 31 to the external airflow of the external gas fan 41. For example, for a CO2 separation efficiency C (40%), the control unit 5 sets the ratio of the internal airflow to the external airflow to "2:1", the internal airflow to 500 L / min, and the external airflow to 250 L / min. Furthermore, for a CO2 separation efficiency B (20%), the control unit 5 sets the ratio of the internal airflow to the external airflow to "2:1", the internal airflow to 3900 L / min, and the external airflow to 1950 L / min. On the other hand, for a CO2 separation efficiency A (18%), the control unit 5 sets the ratio of the internal airflow to the external airflow to "1:1", the internal airflow to 4000 L / min, and the external airflow to 4000 L / min.

[0094] It should be noted that, in this example, the CO2 concentration in object space 2 during the switch from CO2 separation efficiency B (20%) to CO2 separation efficiency C (40%) is... Figure 7 The second concentration in step S8 of the flowchart described later can also be set to 554 ppm using the above formula (3).

[0095] In addition, if Figure 5C As shown, the control unit 5 can also, while keeping the external gas flow rate of the external gas fan 41 fixed at 1000 L / min, adjust only the internal gas flow rate of the internal gas fan 31 for the determined CO2 separation efficiency. For example, the control unit 5 sets the internal gas flow rate to 1000 L / min for CO2 separation efficiency C (40%). Furthermore, the control unit 5 sets the internal gas flow rate to 2400 L / min for CO2 separation efficiency B (20%). Additionally, the control unit 5 sets the internal gas flow rate to 2400 L / min for CO2 separation efficiency A (40%). Figure 5C The example shows a 15% case where the internal gas supply volume is set to 4900 L / min.

[0096] It should be noted that, in this example, the CO2 concentration in object space 2 during the switch from CO2 separation efficiency B (20%) to CO2 separation efficiency C (40%) is... Figure 7 The second concentration in step S8 of the flowchart described later can also be set to 900 ppm using the above formula (3).

[0097] Control unit 5 has such Figures 5A to 5CThe table shown corresponds to the CO2 separation efficiency that the control unit 5 can determine, illustrating the internal gas flow rate of the internal gas fan 31 and the external gas flow rate of the external gas fan 41 used to achieve this CO2 separation efficiency. Furthermore, when the control unit 5 determines the CO2 separation efficiency based on the CO2 concentration within the target space 2, it determines the internal gas flow rate of the internal gas fan 31 and the external gas flow rate of the external gas fan 41 corresponding to the determined CO2 separation efficiency according to the table. The control unit 5 controls the internal gas fan 31 and the external gas fan 41 in a manner that determines the internal gas flow rate and the external gas flow rate.

[0098] It should be noted that, in Figure 5C In the example shown, the external gas flow rate of the external gas fan 41 is fixed. Therefore, the control unit 5 can also be a table that only represents the internal gas flow rate of the internal gas fan 31 used to achieve the determined CO2 separation efficiency, corresponding to a known CO2 separation efficiency. Furthermore, when the control unit 5 determines the CO2 separation efficiency based on the CO2 concentration in the target space 2, it determines the internal gas flow rate of the internal gas fan 31 corresponding to that determined CO2 separation efficiency according to the table. The control unit 5 controls the internal gas fan 31 with the determined internal gas flow rate. Additionally, the control unit 5 controls the external gas fan 41 with a pre-fixed external gas flow rate.

[0099] Next, refer to Figure 6 as well as Figure 7 This describes the control process of the control unit 5 for the internal gas fan 31 and the external gas fan 41. Figure 6 This is a flowchart illustrating a portion of the air supply unit control process executed by control unit 5. Figure 7 This shows the control process of the air supply unit. Figure 6 The following is a flowchart of the subsequent process. It should be noted that in the following description of the air supply control process, "below" can be replaced with "less than", "greater than" can be replaced with "above", "above" can be replaced with "greater than", and "less than" can be replaced with "below".

[0100] The air supply control process is performed by the control unit 5 when there is an instruction from the user to remove CO2 from the target space 2 of the CO2 separation system 1. This air supply control process controls the internal air volume of the internal gas fan 31 and the external air volume of the external gas fan 41 based on the CO2 concentration within the target space 2.

[0101] When the control unit 5 begins executing the air supply control process, it first determines, as an initial setting, the internal air supply volume of the internal air fan 31 and the external air supply volume of the external air fan 41, such that the CO2 separation efficiency of the CO2 separation element 20 is CO2 separation efficiency B (20%) (step S1). Then, the control unit 5 controls the internal air fan 31 and the external air fan 41 to achieve the determined internal and external air supply volumes.

[0102] Here, control unit 5 is used in the air supply unit control process. Figures 5A to 5C The table shown determines the internal gas flow rate of the internal gas fan 31 and the external gas flow rate of the external gas fan 41, which correspond to the CO2 separation efficiency.

[0103] It should be noted that in step S1, the CO2 separation efficiency can also be determined based on the CO2 concentration detected by the CO2 detection unit 8 within the target space 2 as an initial setting. For example, if the CO2 concentration within the target space 2 is less than 1000 ppm, the CO2 separation efficiency can be determined as CO2 separation efficiency C (40%). Furthermore, if the CO2 concentration within the target space 2 is 1000 ppm or more but less than 1200 ppm, the CO2 separation efficiency can be determined as CO2 separation efficiency B (20%). Additionally, if the CO2 concentration within the target space 2 is 1200 ppm or more, the CO2 separation efficiency can be determined as CO2 separation efficiency A (18%). Furthermore, the control unit 5 can determine the internal gas flow rate of the internal gas fan 31 and the external gas flow rate of the external gas fan 41 in a manner consistent with the determined CO2 separation efficiency.

[0104] Next, the control unit 5 determines whether the current CO2 separation efficiency of the CO2 separation element 20 is CO2 separation efficiency A (18%) (step S2). If the result is that the control unit 5 determines that the CO2 separation efficiency is CO2 separation efficiency A (step S2: yes), then the CO2 concentration in the target space 2 detected by the CO2 detection unit 8 is obtained, and it is determined whether the CO2 concentration is below the first concentration (e.g., 1000 ppm) (step S3).

[0105] If the result is that the control unit 5 determines that the CO2 concentration is below the first concentration (step S3: Yes), then the CO2 separation efficiency of the CO2 separation element 20 corresponding to the CO2 concentration is determined to be CO2 separation efficiency B (20%), and the amount of CO2 removed per unit time is reduced (step S4). Furthermore, the control unit 5 determines the internal gas flow rate of the internal gas fan 31 and the external gas flow rate of the external gas fan 41 corresponding to the CO2 separation efficiency B (20%), and controls the internal gas fan 31 and the external gas fan 41 in a manner that determines the internal gas flow rate and the external gas flow rate. Afterwards, the control unit 5 returns to the processing of step S2.

[0106] On the other hand, if the result of the judgment in step S3 is that the control unit 5 determines that the CO2 concentration is greater than the first concentration (e.g., 1000 ppm) (step S3: No), then the judgment in step S5 is performed while maintaining the CO2 separation efficiency of the CO2 separation element 20 corresponding to the CO2 concentration at CO2 separation efficiency A (18%). In the judgment in step S5, the control unit 5 determines the operating duration at CO2 separation efficiency A (18%) and determines whether the operating duration is greater than or equal to the first time (e.g., 30 minutes) (step S5).

[0107] If the result is that the operating duration at CO2 separation efficiency A (18%) is determined to be a first time (e.g., 30 minutes) or more (step S5: Yes), then it means the following: That is, it means that even if CO2 separation system 1 operates at CO2 separation efficiency A (18%) for a first time or more, the CO2 concentration in the target space 2 does not decrease to below the first concentration. In addition, the operation at CO2 separation efficiency A (18%) is the operating mode with the highest CO2 removal per unit time compared to CO2 separation efficiencies B and C.

[0108] Therefore, in this situation (step S5: Yes), the control unit 5 reports a window ventilation warning to the user (step S6) and transfers the process to step S2. The window ventilation warning can be reported via voice, or by illuminating an LED installed in the CO2 separation system 1, or by displaying a message on an LCD screen. Furthermore, the CO2 separation system 1 can also communicate with portable information terminals such as smartphones, and the window ventilation warning can also be issued by displaying a notification on that portable information terminal.

[0109] On the other hand, if the result of the judgment in step S5 is that the operating duration under the CO2 separation efficiency A (18%) is less than the first time (step S5: no), then the control unit 5 directly returns to the processing of step S2.

[0110] Furthermore, if the result of the judgment in step S2 is that the control unit 5 determines that the current CO2 separation efficiency of the CO2 separation element 20 is not the CO2 separation efficiency A (step S2: No), then... Figure 7 The judgment transition in step S7 is shown. In the judgment in step S7, it is determined whether the current CO2 separation efficiency of CO2 separation element 20 is CO2 separation efficiency B (20%) (step S7).

[0111] If the result is that the control unit 5 determines that the CO2 separation efficiency is CO2 separation efficiency B (step S7: yes), then the CO2 concentration in the object space 2 detected by the CO2 detection unit 8 is obtained, and it is determined whether the CO2 concentration is below the second concentration (e.g., 800 ppm) (step S8).

[0112] If the result is that the control unit 5 determines that the CO2 concentration is below the second concentration (step S8: Yes), then the CO2 separation efficiency of the CO2 separation element 20 corresponding to the CO2 concentration is determined to be CO2 separation efficiency C (40%), and the amount of CO2 removed per unit time is reduced (step S9). Furthermore, the control unit 5 determines the internal gas flow rate of the internal gas fan 31 and the external gas flow rate of the external gas fan 41 corresponding to the CO2 separation efficiency C (40%), and controls the internal gas fan 31 and the external gas fan 41 in a manner that determines the internal gas flow rate and external gas flow rate. Afterwards, the control unit 5 returns to... Figure 6 The process shown is step S2.

[0113] On the other hand, if the result of the judgment in step S8 is that the control unit 5 determines that the CO2 concentration is greater than the second concentration (step S8: no), then it is determined whether the CO2 concentration detected by the CO2 detection unit 8 in the object space 2 is greater than the third concentration (e.g., 1000 ppm) (step S10).

[0114] If the result is that the control unit 5 determines that the CO2 concentration is greater than the third concentration (step S10: Yes), then the CO2 separation efficiency of the CO2 separation element 20 corresponding to the CO2 concentration is determined to be CO2 separation efficiency A (18%), and the CO2 removal amount per unit time is increased (step S11). Furthermore, the control unit 5 determines the internal gas flow rate of the internal gas fan 31 and the external gas flow rate of the external gas fan 41 corresponding to the CO2 separation efficiency A (18%), and controls the internal gas fan 31 and the external gas fan 41 in a manner that determines the internal gas flow rate and external gas flow rate. Afterwards, the control unit 5 returns to... Figure 6 The process shown is step S2.

[0115] On the other hand, if the result of the judgment in step S10 is that the CO2 concentration is below the third concentration (step S10: Yes), then the CO2 concentration in the object space 2 is greater than the second concentration and below the third concentration. Therefore, the control unit 5 maintains the CO2 separation efficiency of the CO2 separation element 20 corresponding to the CO2 concentration at the CO2 separation efficiency B (20%), and returns to the previous state. Figure 6 The process shown is step S2.

[0116] Furthermore, if the determination in step S7 indicates that the current CO2 separation efficiency of the CO2 separation element 20 is not CO2 separation efficiency B (step S7: No), then the current CO2 separation efficiency of the CO2 separation element 20 is CO2 separation efficiency C (40%). Therefore, in this case, the control unit 5 obtains the CO2 concentration in the target space 2 detected by the CO2 detection unit 8 and determines whether the CO2 concentration is greater than the fourth concentration (e.g., 1000 ppm) (step S12).

[0117] If the result is that the control unit 5 determines that the CO2 concentration is greater than the fourth concentration (step S12: Yes), then the CO2 separation efficiency of the CO2 separation element 20 corresponding to the CO2 concentration is determined to be CO2 separation efficiency B (20%), and the CO2 removal amount per unit time is increased (step S12). Furthermore, the control unit 5 determines the internal gas flow rate of the internal gas fan 31 and the external gas flow rate of the external gas fan 41 corresponding to the CO2 separation efficiency B (20%), and controls the internal gas fan 31 and the external gas fan 41 in a manner that determines the internal gas flow rate and external gas flow rate. Afterwards, the control unit 5 returns to... Figure 6 The process shown is step S2.

[0118] Furthermore, if the result of the judgment in step S12 is that the CO2 concentration is below the fourth concentration (step S12: Yes), then the control unit 5, while maintaining the CO2 separation efficiency of the CO2 separation element 20 corresponding to the CO2 concentration at the CO2 separation efficiency C (40%), returns to the previous state. Figure 6 The process shown is step S2.

[0119] The CO2 separation system 1 of the first embodiment described above has the following effects.

[0120] (1) The CO2 separation system 1 uses a CO2 separation element 20 to separate CO2 from the air 39a inside the target space 2 and release it outside, thereby reducing the CO2 concentration in the target space 2. The air supply to the CO2 separation element 20 is provided by an internal gas fan 31 and an external gas fan 41. The CO2 separation efficiency of the CO2 separation element 20 is determined, for example, by the air supply volume to the CO2 separation element 20. Here, the CO2 separation system 1 uses a CO2 detection unit 8 to detect the CO2 concentration in the target space 2, and uses a control unit 5 to determine the required CO2 separation efficiency based on the detected CO2 concentration. Furthermore, the CO2 separation system 1 uses the control unit 5 to determine the air supply volume of the internal gas fan 31 and the external gas fan 41 in a manner that becomes the determined CO2 separation efficiency. Thus, the CO2 separation system 1 determines the sufficient CO2 separation efficiency required to reduce the CO2 concentration in the target space 2, and can determine the air supply volume of the internal gas fan 31 and the external gas fan 41 to the CO2 separation element 20 in a manner that becomes the CO2 separation efficiency. Therefore, CO2 separation system 1 can remove CO2 from object space 2 without consuming more electricity. Thus, CO2 separation system 1 can efficiently remove CO2 from object space 2.

[0121] (2) In the CO2 separation system 1, air 39a from the target space 2 is introduced and circulated into the internal gas duct 16 as internal gas, and after being separated from CO2 by the CO2 separation element 20, it is returned to the target space 2 as air 39b. The internal gas in the internal gas duct 16 is supplied by the internal gas fan 31. In addition, in the CO2 separation system 1, outdoor air 49a is introduced and circulated into the external gas duct 17 as external gas, and after being introduced into CO2 by the CO2 separation element 20, it is released to the outside as air 49b. The external gas in the external gas duct 17 is supplied by the external gas fan 41. Furthermore, the CO2 separation system 1 uses the control unit 5 to adjust at least the internal gas supply volume of the internal gas fan 31 in a manner that determines the CO2 separation efficiency based on the CO2 concentration in the target space 2, thereby determining the supply volume to the CO2 separation element 20. Therefore, the CO2 separation system 1 can remove CO2 from the object space 2 without consuming more electricity, thus enabling efficient removal of CO2 from the object space 2.

[0122] (3) Control unit 5, for example, has a CO2 concentration in object space 2 that is a second concentration (refer to...). Figure 7 In the case of a first CO2 concentration below step S8), the CO2 separation efficiency is determined as CO2 separation efficiency C (equivalent to the first CO2 separation efficiency of the present invention). Furthermore, the CO2 concentration in the target space 2 of the control unit 5 is greater than the fourth concentration (refer to...). Figure 7In step S12), when the CO2 concentration is the second concentration, the CO2 separation efficiency is determined to be a CO2 separation efficiency B (equivalent to the second CO2 separation efficiency of the present invention), which is lower than the CO2 separation efficiency C. That is, when the CO2 concentration in the target space 2 is a second CO2 concentration that is higher than the first CO2 concentration, the control unit 5 determines a CO2 separation efficiency that is lower than the CO2 separation efficiency determined for the first CO2 concentration. Furthermore, the control unit 5 determines the air volume supplied to the CO2 separation element 20 in a manner that becomes the determined CO2 separation efficiency. Thus, when the CO2 concentration in the target space 2 is low, the CO2 separation system 1 can achieve power saving by setting the CO2 separation efficiency to a high level and reducing the air volume supplied to the CO2 separation element 20 in accordance with the CO2 separation efficiency. In addition, when the CO2 concentration in the target space 2 is high, the CO2 separation system 1 can remove CO2 from the target space 2 without consuming more electricity by setting the CO2 separation efficiency to a low level and increasing the air volume supplied to the CO2 separation element 20 in accordance with the CO2 separation efficiency. Therefore, CO2 separation system 1 can efficiently remove CO2 from object space 2.

[0123] Furthermore, as described above, the CO2 separation system 1 can achieve the effect corresponding to each structure.

[0124] (Second Implementation)

[0125] Next, refer to Figure 8A as well as Figure 8B The CO2 separation system 1 of the second embodiment will be described.

[0126] In the CO2 separation system 1 of the first embodiment, the control unit 5 determines the CO2 separation efficiency based on the CO2 concentration in the target space 2 detected by the CO2 detection unit 8, and determines the air volume of the internal gas fan 31 and the external gas fan 41 in a manner that becomes the determined CO2 separation efficiency.

[0127] In contrast, in the CO2 separation system 1 of the second embodiment, the control unit 5 determines the power consumption of the CO2 separation system 1 required to reduce the CO2 concentration based on the CO2 concentration detected by the CO2 detection unit 8 within the target space 2. The control unit 5 determines the internal gas flow rate of the internal gas fan 31 and the external gas flow rate of the external gas fan 41 in a manner consistent with the determined power consumption. Furthermore, the control unit 5 controls the internal gas fan 31 and the external gas fan 41 in a manner consistent with the determined internal and external gas flow rates.

[0128] Figure 8AThe control unit 5 of the CO2 separation system 1 described in the second embodiment utilizes... Figure 9A The graph shown is a graph of power consumption determined based on the CO2 concentration within object space 2.

[0129] like Figure 8A As shown, the control unit 5 determines the power consumption of the CO2 separation system 1 from three power consumptions—power consumption A, power consumption B, and power consumption C—based on the CO2 concentration within the target space 2. That is, it determines the power consumption with a higher CO2 removal rate per unit time when the CO2 concentration within the target space 2 is high, and determines the power consumption with a lower CO2 removal rate per unit time when the CO2 concentration within the target space 2 is low.

[0130] The power consumption A, power consumption B, and power consumption C are predetermined during the design phase of CO2 separation system 1. For example, power consumption B is 50% of power consumption A, and power consumption C is 5% of power consumption A. In addition, power consumption A is set to achieve the same CO2 removal performance (CO2 removal rate per unit time) with the same power consumption in normal ventilation and CO2 separation system 1.

[0131] Here, power consumption B and power consumption C are set to be lower than power consumption A. Therefore, the control unit 5 determines the power consumption of the CO2 separation element 20 to be below power consumption A, thus enabling the CO2 separation system 1 to achieve energy savings compared to normal ventilation.

[0132] It should be noted that the power consumption B and power consumption C are appropriately set according to the characteristics of the CO2 separation element 20, and are not limited to the values ​​mentioned above.

[0133] The relationship between power consumption and CO2 concentration in target space 2 is determined during the design phase of CO2 separation system 1 as follows. First, the amount of CO2 removed per unit time under power consumption B is determined in a way that "the amount of CO2 removed can maintain a baseline concentration of 1000 ppm when there are N people in target space 2".

[0134] Therefore, during the design phase of the CO2 separation system 1, the membrane size of the CO2 separation membrane 22 of the CO2 separation element 20 is also determined. Furthermore, the CO2 concentration (equivalent to...) within the target space 2 where the power consumption shifts from C to B... Figure 7 The fourth concentration in step S12 of the flowchart shown is determined to be 1000 ppm. Additionally, the CO2 concentration (equivalent to...) in the object space 2 where power consumption shifts from A to B... Figure 6 The first concentration in step S3 of the flowchart shown is determined to be 1000 ppm.

[0135] On the other hand, the CO2 concentration (equivalent to) in object space 2 where power consumption shifts from B to C Figure 7 The second concentration in step S8 of the flowchart shown can also be determined to be 1000 ppm. However, if the CO2 concentration in the target space 2 where power consumption C is switched to power consumption B and the CO2 concentration in the target space 2 where power consumption B is switched to power consumption C are both set to 1000 ppm, the following problem may occur. That is, if the CO2 concentration in the target space 2 is around 1000 ppm, the power consumption determined by the control unit 5 may frequently switch between power consumption B and power consumption C.

[0136] Therefore, the CO2 concentration (equivalent to) in object space 2 where power consumption shifts from B to C is... Figure 7 The second concentration in step S8 of the flowchart shown can also be determined as follows. The CO2 removal rate per unit time under power consumption C can be determined relative to the CO2 removal rate per unit time under power consumption B as "the removal rate that can maintain a baseline CO2 concentration of 1000 ppm when there are n people in object space 2 (n < N)". Therefore, the CO2 concentration in object space 2 when switching from power consumption B to power consumption C (equivalent to Figure 7 The second concentration of step S8 in the flowchart shown can be determined according to equation (4).

[0137] Second concentration = (n / N) × (Fourth concentration - external gas concentration) + external gas concentration... (4) Equation

[0138] Here, the external gas concentration is the CO2 concentration in the external gas, for example, 400 ppm. Assuming that the CO2 removal per unit time under power consumption B is determined to be "the removal amount that can maintain the baseline CO2 concentration of 1000 ppm when there are 4 people in object space 2" (i.e., N=4), and the CO2 removal per unit time under power consumption C is determined to be "the removal amount that can maintain the baseline CO2 concentration of 1000 ppm when there are 3 people in object space 2" (i.e., n=3), the CO2 concentration (second concentration) in object space 2 when switching from power consumption B to power consumption C is 850 ppm according to equation (4).

[0139] The control unit 5 compares the first to fourth concentrations determined as described above with the CO2 concentration in the target space 2 to determine the power consumption of the CO2 separation element 20 from the power consumption A to power consumption C. Furthermore, the control unit 5 determines the internal gas flow rate of the internal gas fan 31 and the external gas flow rate of the external gas fan 41 based on the determined power consumption, and controls the internal gas fan 31 and the external gas fan 41 based on the determined internal and external gas flow rates.

[0140] Figure 8B This is a diagram illustrating an example of the internal airflow rate of the internal air fan 31 and the external airflow rate of the external air fan 41, determined by the power consumption as determined by the control unit 5. For example, Figure 8B This is an example where the control unit 5 determines the internal air volume and the external air volume by making the internal air volume of the internal air fan 31 and the external air volume of the external air fan 41 a ratio of "1:1".

[0141] In this example, control unit 5 sets both the internal and external air supply volumes to 1000 L / min for power consumption C (5% of power consumption A). Additionally, control unit 5 sets both the internal and external air supply volumes to 2550 L / min for power consumption B (50% of power consumption A). Furthermore, control unit 5 sets both the internal and external air supply volumes to 4000 L / min for power consumption A (100%).

[0142] It should be noted that the control unit 5 does not need to fix the ratio of the internal air volume of the internal air fan 31 to the external air volume of the external air fan 41 to "1:1" based on the determined power consumption. It can be fixed to another ratio (e.g., "2:1"), or the ratio can be changed according to the power consumption. In addition, the control unit 5 can also adjust only the internal air volume of the internal air fan 31 based on the determined power consumption, while keeping the external air volume of the external air fan 41 fixed.

[0143] The control unit 5 of the CO2 separation system 1 in the second embodiment, configured as described above, performs... Figure 6 as well as Figure 7 The air supply unit control process shown in the flowchart is the same as that in the second embodiment. However, the air supply unit control process in the second embodiment is executed differently than... Figure 6 as well as Figure 7 The air supply unit control process shown replaces "CO2 separation efficiency A" with "power consumption A", "CO2 separation efficiency B" with "power consumption B", and "CO2 separation efficiency C" with "power consumption C".

[0144] The CO2 separation system 1 of the second embodiment described above has the following effects.

[0145] (4) The CO2 separation system 1 uses the CO2 detection unit 8 to detect the CO2 concentration in the target space 2, and the control unit 5 determines the power consumption required to remove CO2 based on the detected CO2 concentration. Furthermore, the CO2 separation system 1 uses the control unit 5 to determine the airflow rate of the internal gas fan 31 and the external gas fan 41 in a manner consistent with the determined power consumption. Thus, the CO2 separation system 1 determines the sufficient power consumption required to reduce the CO2 concentration in the target space 2, and can determine the airflow rate of the internal gas fan 31 and the external gas fan 41 to the CO2 separation element 20 in a manner consistent with the CO2 separation efficiency. Therefore, the CO2 separation system 1 can remove CO2 from the target space 2 without consuming the above amount of power. Therefore, the CO2 separation system 1 can efficiently remove CO2 from the target space 2.

[0146] Furthermore, the CO2 separation system 1 of the second embodiment achieves the same effect through the same structure as the CO2 separation system 1 of the first embodiment.

[0147] The present invention has been described above based on various embodiments, but the present invention is not limited to any of the above embodiments, and various modifications and variations can be easily deduced without departing from the spirit of the present invention. For example, each embodiment, including the variations described below, can also be modified by adding or replacing one or more parts of the structure of other embodiments to the embodiment or by replacing one or more parts of the structure of the embodiment. In addition, the values ​​given in each embodiment are examples, and other values ​​can certainly be used.

[0148] In the above embodiments, the structure is designed to introduce outdoor (outside the building) air as air 49a, but it is not limited to this. For example, it can be configured to introduce air from the roof of the building as air 49a, or it can be configured to introduce air from an adjacent room where no one is present. Even so, air with a lower CO2 concentration than the air 39a in the target space 2 where the CO2 concentration is higher due to the presence of people can be introduced into the CO2 separation element 20 as air 49a. Therefore, the same effect of CO2 moving from the air 39a with a higher CO2 concentration to the air 49a with a relatively lower CO2 concentration can be achieved, and the increase in CO2 concentration in the target space 2 can be suppressed.

[0149] Industrial applicability

[0150] This invention is useful as a CO2 separation system capable of efficiently removing CO2 from object spaces with a large number of people.

[0151] Explanation of reference numerals in the attached figures

[0152] 1 CO2 separation system

[0153] 2 Object Space

[0154] 5. Control Department

[0155] 6-layer structure

[0156] 8 CO2 Detection Department

[0157] 10. Shell

[0158] 14 Framework

[0159] 16 Internal gas ventilation path

[0160] 16a First internal gas ventilation path

[0161] 16b Second internal gas ventilation path

[0162] 16c Third Internal Gas Ventilation Path

[0163] 17 External gas ventilation path

[0164] 17a First external gas ventilation path

[0165] 17b Second external gas ventilation path

[0166] 17c Third External Gas Ventilation Path

[0167] 20 CO2 separation element

[0168] 21 CO2 Separation Element Section

[0169] 22 CO2 separation membrane

[0170] 22a First CO2 separation membrane

[0171] 22b Second CO2 separation membrane

[0172] 22c Third CO2 separation membrane

[0173] 22d Fourth CO2 separation membrane

[0174] 22e Fifth CO2 separation membrane

[0175] 31 Internal gas fan

[0176] 33 Internal gas inlet

[0177] 35 Gas supply port

[0178] 37 Internal Gas Filter

[0179] 39a Air

[0180] 39b Air

[0181] 41 External gas fan

[0182] 43 External gas inlet

[0183] 45 Exhaust port

[0184] 47 External Gas Filter

[0185] 49a Air

[0186] 49b Air

[0187] 51 Intake inlet inside the house

[0188] 52 Internal gas inlet pipe

[0189] 53. Indoor air outlet

[0190] 54 Internal gas exhaust pipe

[0191] 55 Outdoor suction inlet

[0192] 56 External gas inlet pipe

[0193] 57. Outdoor air outlet

[0194] 58. External gas is blown out of the pipe.

Claims

1. A CO2 separation system, wherein, The CO2 separation system includes: The CO2 separation unit separates carbon dioxide (CO2) from the air in the indoor space and releases it outside; The CO2 detection unit detects the CO2 concentration within the object space; The air supply unit supplies air to the CO2 separator; and The control unit controls the air supply unit. The control unit determines the air volume supplied by the air supply unit to the CO2 separation unit in a manner that determines the CO2 separation efficiency based on the CO2 concentration detected by the CO2 detection unit.

2. The CO2 separation system according to claim 1, wherein, The CO2 separation system includes: An internal gas ventilation system that introduces and circulates air from the object space as internal gas, and returns it to the object space; and An external air duct allows outside air to be drawn in and circulated, and then released to the outside. The air supply unit includes: an internal gas fan for supplying internal gas in the internal gas airflow path; and an external gas fan for supplying external gas in the external gas airflow path. The CO2 separation unit separates CO2 from the internal gas flowing through the internal gas duct and introduces it into the external gas flowing through the external gas duct. The control unit determines the air volume supplied to the CO2 separator by adjusting at least the internal gas supply volume of the internal gas fan.

3. The CO2 separation system according to claim 1, wherein, The control unit determines the CO2 separation efficiency as a first CO2 separation efficiency when the CO2 concentration is a first CO2 concentration, and determines the CO2 separation efficiency as a second CO2 separation efficiency that is lower than the first CO2 separation efficiency when the CO2 concentration is a second CO2 concentration that is higher than the first CO2 concentration. The control unit determines the air volume supplied to the CO2 separation unit in a manner that corresponds to the determined CO2 separation efficiency.

4. The CO2 separation system according to claim 2, wherein, The control unit determines the CO2 separation efficiency as a first CO2 separation efficiency when the CO2 concentration is a first CO2 concentration, and determines the CO2 separation efficiency as a second CO2 separation efficiency that is lower than the first CO2 separation efficiency when the CO2 concentration is a second CO2 concentration that is higher than the first CO2 concentration. The control unit determines the air volume supplied to the CO2 separation unit in a manner that corresponds to the determined CO2 separation efficiency.

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