Air conditioning system, and building air conditioning system

Abstract

To provide an air conditioning system that recovers carbon dioxide, and can effectively utilize recovered carbon dioxide.SOLUTION: An air conditioning system 1 includes carbon dioxide increasing part 40 in which the concentration of carbon dioxide increases, an adsorption / desorption part 50, and a recovery part 60, where the adsorption / desorption part 50 has adsorbent having adsorption capability, supplies air to be treated containing carbon dioxide from the carbon dioxide increasing part 40 to the adsorption / desorption part 50, brings the air to be treated in contact with the adsorbent to allow the adsorbent to adsorb a part or all of carbon dioxide from the air to be treated into treated air, discharges the treated air from the adsorption / desorption part 50, desorbs carbon dioxide adsorbed to the adsorbent, discharges the desorbed carbon dioxide from the adsorption / desorption part 50, and supplies it to the recovery part 60.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an air conditioning system and a building air conditioning system. [Background technology]

[0002] The Building Environmental Sanitation Management Standards stipulate that the carbon dioxide content in rooms equipped with air conditioning equipment must be 1000 ppm (volume basis; the same applies hereinafter in this specification) or less. Thus, in buildings equipped with air conditioning equipment, technology to remove carbon dioxide from the air inside the rooms is desired.

[0003] For example, Patent Document 1 proposes an air conditioning system that includes a rotor partitioned into a treatment zone in which air to be treated that contains carbon dioxide is absorbed by an amine-supported solid absorbent, and a regeneration zone in which the carbon dioxide absorbed by the absorbent is desorbed into regeneration air, and that is configured so that the enthalpy difference between the air to be treated that is supplied to the treatment zone and the regeneration air that is supplied to the regeneration zone falls within a specific range. According to the invention of Patent Document 1, it is intended to remove carbon dioxide from indoor air and improve air quality. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-75715 A Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, carbon dioxide can be used to produce valuable materials if it is recovered using an appropriate method. However, in the technology of Patent Document 1, the removed carbon dioxide is discharged outdoors, and recovery of carbon dioxide is not taken into consideration.

[0006] Therefore, an object of the present invention is to provide an air conditioning system, or building air conditioning system, in an air conditioning system for a building that can capture carbon dioxide and effectively utilize the captured carbon dioxide. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention has the following aspects. [1] An air conditioning system that captures carbon dioxide and reuses the captured carbon dioxide, The system includes a carbon dioxide increasing section in which the concentration of carbon dioxide increases, an air supply section that supplies outside air to the carbon dioxide increasing section, a mixing section, an air conditioning section, an adsorption / desorption section, and a recovery section, The mixing section is located downstream of the adsorption / desorption section, The adsorption / desorption unit has an adsorbent having a carbon dioxide adsorption ability, The adsorption / desorption unit has two or more adsorption / desorption cylinders filled with the adsorbent, Two or more of the adsorption / desorption tubes are arranged in parallel, and air flow rate regulators are provided before and after the adsorption / desorption tubes, air to be treated that contains carbon dioxide is supplied from the carbon dioxide increasing section to the adsorption / desorption section, and adsorption of the carbon dioxide and desorption of the carbon dioxide are alternately switched between any one of the adsorption / desorption tubes and any other one of the adsorption / desorption tubes, and the air to be treated is brought into contact with the adsorbent in any one of the adsorption / desorption tubes, thereby adsorbing part or all of the carbon dioxide from the air to be treated onto the adsorbent to obtain treated air, the treated air is discharged from the adsorption / desorption section, and the treated air is supplied to the mixing section, The carbon dioxide adsorbed to the adsorbent is desorbed, the desorbed carbon dioxide is discharged from the adsorption / desorption section, and the carbon dioxide is supplied to the recovery section; The treated air discharged from the adsorption / desorption unit and the outside air supplied from the air supply unit are mixed in the mixing unit to obtain a mixed fluid; an air conditioning unit that purifies the mixed fluid supplied from the mixing unit and adjusts the temperature, and then supplies the mixed fluid from the air conditioning unit to the carbon dioxide increasing unit. [2] The air conditioning system according to [1], wherein the adsorption / desorption unit desorbs the carbon dioxide adsorbed in the adsorbent by reducing the internal pressure.

[0008] [3] A building air conditioning system having multiple air conditioning systems described in [1] or [2] on different floors. Effect of the Invention

[0009] According to the air conditioning system and building air conditioning system of the present invention, carbon dioxide can be captured in the air conditioning system in a building and the captured carbon dioxide can be effectively utilized. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic diagram showing an air conditioning system according to one embodiment of the present invention. [Diagram 2] 1 is a schematic diagram showing a building air conditioning system according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] <Air conditioning system> The air conditioning system of the present invention comprises a carbon dioxide increasing section in which the concentration of carbon dioxide increases, an adsorption / desorption section having an adsorbent, an air discharge section, a carbon dioxide discharge section, and a recovery section. An air conditioning system according to one embodiment of the present invention will be described in detail below with reference to FIG.

[0012] As shown in FIG. 1, the air conditioning system 1 of the present embodiment has an air supply section 10, a mixing section 20, an air conditioning section 30, a carbon dioxide increasing section 40, an adsorption / desorption section 50, and a recovery section 60. The air supply unit 10 and the mixing unit 20 are connected by a pipe L1. The mixing unit 20 and the air conditioning unit 30 are connected by a pipe L2. The air conditioning unit 30 and the carbon dioxide increase unit 40 are connected by a pipe L3. The carbon dioxide increase unit 40 is connected to a pipe L4. The pipe L4 is connected to the adsorption / desorption unit 50 at a branch 101. The pipe L4 is provided with a blower A2. The adsorption / desorption unit 50 is connected to a pipe L11 at a branch 102. The pipe L11 is connected to a pipe L13 at a branch 104. The adsorption / desorption unit 50 is connected to a pipe L12 at a branch 103. The pipe L12 is connected to a pipe L14 at a branch 105. The pipe L13 is connected to the mixing unit 20. The pipe L14 is connected to the recovery unit 60. The arrows in the figure indicate the direction of movement of a fluid such as air.

[0013] <Air supply section> The air supply unit 10 supplies outside air to the carbon dioxide increasing unit 40. The air supply unit 10 of this embodiment has an outside air intake 12, a pipe L0, and a damper D1. The outside air intake 12 and the damper D1 are connected by the pipe L0. The damper D1 is connected to the mixer 20 via the pipe L1. The pipes L0 and L1 may be provided with, for example, a blower that imparts energy to the gas by the rotational motion of an impeller.

[0014] The outside air intake 12 may be, for example, a louver that can introduce outside air and has a rain guard that prevents rainwater from entering. Examples of the damper D1 include an air flow regulator that can adjust the flow rate by opening and closing a valve, and a fire damper that has a fire spread prevention function and is used in an opening facing an outer wall. The pipe L0 may be, for example, a duct made of metal or resin, etc. The pipe L1 may be, for example, a duct similar to the pipe L0, etc.

[0015] <Mixing section> The mixer 20 mixes the outside air with the treated air. The mixing section 20 may be, for example, a chamber made of metal or resin. The pipe L2 may be a duct similar to the pipe L0.

[0016] <Air Conditioning Department> The air conditioning section 30 purifies the mixture of outside air and the treated air, adjusts the temperature, and supplies the mixture to the carbon dioxide increasing section 40 . The air conditioning unit 30 includes a filter 32 and a blower A1. An example of the air conditioning section 30 is an air handling unit (AHU) or other such device. The filter 32 may be, for example, a filter capable of removing dust particles and the like from the air. The blower A1 may be, for example, a blower that imparts energy to gas by the rotational motion of an impeller.

[0017] <Carbon Dioxide Increase Section> An example of the carbon dioxide increasing section 40 is a room in an office or the like where people are active indoors. In the carbon dioxide increasing section 40, the concentration of carbon dioxide increases as people breathe. Other examples of the carbon dioxide increasing section 40 include a room equipped with a combustion type heater, a baking device, or the like. In this specification, the carbon dioxide increase section 40 means a space where the concentration of carbon dioxide can increase compared to the atmosphere, etc., and does not necessarily mean a space where the concentration of carbon dioxide continues to increase. The carbon dioxide increase section 40 also includes the moment when the concentration of carbon dioxide decreases. The carbon dioxide increasing section 40 has air inlets 41 and 42 and an exhaust port 43. A pipe L3 is connected to the air inlets 41 and 42. A pipe L4 is connected to the exhaust port 43. The air inlets 41 and 42 may be, for example, air vents made of metal or resin. The exhaust port 43 may be, for example, a metal or resin air vent. An example of the pipe L4 is a return air duct made of metal or resin.

[0018] <Adsorption / desorption part> The adsorption / desorption section 50 has two adsorption / desorption cylinders 51 and 52, pipes L5 and L6, air discharge sections L7 and L8, dampers D3 to D6, and carbon dioxide discharge sections L9 and L10. The adsorption / desorption cylinder 51 is connected to the pipe L5, the air discharge section L7, and the carbon dioxide discharge section L9. The adsorption / desorption cylinder 52 is connected to the pipe L6, the air discharge section L8, and the carbon dioxide discharge section L10. The air discharge section L7 and the air discharge section L8 are connected by a branch 102. That is, the adsorption / desorption cylinder 51 and the adsorption / desorption cylinder 52 are arranged in parallel. By arranging the adsorption / desorption cylinder 51 and the adsorption / desorption cylinder 52 in parallel, carbon dioxide can be adsorbed on one side and desorbed on the other side. As used herein, "adsorption" refers to the adsorption of a liquid or gas onto the surface of another solid or liquid. "Desorption" refers to the separation of an adsorbed substance from the adsorption interface, also called desorption. "Adsorption-desorption" refers to both or either adsorption and desorption. A damper D3 is provided in the pipe L5. A damper D4 is provided in the pipe L6. A damper D5 is provided in the air discharge section L7. A damper D6 is provided in the air discharge section L8. That is, dampers are provided before and after the adsorption / desorption cylinders 51 and 52. The pipes L5 and L6 are connected to each other at a branch 101. The air discharge section L7 and the air discharge section L8 are connected to each other at a branch 102. The carbon dioxide discharge part L9 is provided with a valve B1, and the carbon dioxide discharge part L10 is provided with a valve B2. The dampers D3 to D6 and the valves B1 and B2 are connected to the control unit C1. The adsorption / desorption cylinders 51 and 52 are filled with an adsorbent capable of adsorbing carbon dioxide. The adsorption / desorption cylinders 51 and 52 are cylindrical members capable of carrying an adsorbent. Examples of the adsorption / desorption cylinders 51 and 52 include cylindrical members made of metal or resin, and cylindrical members obtained by corrugating a non-flammable sheet such as ceramic fiber paper or glass fiber paper. The adsorbent is not particularly limited as long as it has the ability to adsorb carbon dioxide. Examples of the adsorbent include zeolite, silica gel, activated carbon, solid absorbents carrying amines such as triethanolamine and monoethanolamine, amine-based weakly basic anion exchange resins, etc. As the adsorbent, zeolite, silica gel, and activated carbon are preferred, and zeolite and silica gel are more preferred.

[0019] The dampers D3, D4, D5, and D6 include air volume regulators whose opening and closing can be controlled by the control unit C1. The valves B1 and B2 include electromagnetic valves whose opening and closing can be controlled by the control unit C1. The control unit C1 may be a computer that can adjust the opening and closing of dampers D3, D4, D5, and D6 and valves B1 and B2. By adjusting the opening and closing of dampers D3, D4, D5, and D6 and valves B1 and B2 with the control unit C1, the adsorption of carbon dioxide and the desorption of carbon dioxide can be controlled so that the adsorption and desorption tubes 51 and 52 can be alternately switched.

[0020] The pipe L5 may be a duct similar to the pipe L0. The pipe L6 may be a duct similar to the pipe L0.

[0021] The air exhaust units L7 and L8 exhaust treated air in which a part or all of the carbon dioxide has been adsorbed by the adsorbent from the air to be treated. Examples of the air exhaust units L7 and L8 include ducts made of metal or resin. The air exhaust units L7 and L8 may be provided with a blower, a suction pump, or the like. In this embodiment, the air discharge parts L7 and L8 are connected to a pipe L11 at a branch 102. The pipe L11 is provided with a damper D7. The pipe L11 is connected to a pipe L13 at a branch 104. The pipe L13 is provided with a damper D8. The pipe L11 may be a duct similar to the pipe L0. The pipe L13 may be a duct similar to the pipe L0. An example of the damper D7 is an air volume regulator that can adjust the flow rate by opening and closing a valve. The damper D8 may be an air volume regulator similar to the damper D7. The pipe L11 may be provided with a fire damper or the like other than the damper D7. The pipe L13 may be provided with a fire damper or the like other than the damper D8.

[0022] The carbon dioxide discharge parts L9 and L10 discharge the carbon dioxide desorbed from the adsorbent. Examples of the carbon dioxide discharge parts L9 and L10 include metal or resin pipes. The carbon dioxide discharge parts L9 and L10 may be provided with a blower, a suction pump, or the like. In this embodiment, the carbon dioxide discharge parts L9 and L10 are connected to a pipe L12 at a branch 103. The pipe L12 is connected to a pipe L14 at a branch 105. The pipe L14 is provided with a pump P1. The pipe L12 may be a duct similar to the pipe L0. The pipe L14 may be a duct similar to the pipe L0. The pump P1 may be a vacuum pump or a suction pump.

[0023] <Collection Department> One end of a pipe L14 is connected to the recovery unit 60. The other end of the pipe L14 is connected to, for example, a carbon dioxide discharge unit of another air conditioning system (not shown). The recovery section 60 is supplied with the carbon dioxide desorbed from the adsorbent. The recovery unit 60 may be, for example, a container such as a tank that can store carbon dioxide.

[0024] <Carbon dioxide recovery method (air conditioning method)> The carbon dioxide capture method of the present invention includes an adsorption step, a desorption step, and a capture step. The carbon dioxide recovery method of the present invention will be described using an air conditioning method that utilizes an air conditioning system 1 as an example. Each step will be described in detail below with reference to FIG.

[0025] <Adsorption process> The adsorption step is a step in which the air to be treated that contains carbon dioxide and is discharged from the carbon dioxide increasing section 40 is brought into contact with the adsorbent, thereby causing the adsorbent to adsorb part or all of the carbon dioxide. In the adsorption / desorption unit 50, the opening and closing of the dampers D3, D4, D5, and D6 and the valves B1 and B2 are adjusted by a control unit C1.

[0026] In the adsorption step, first, the damper D3 is opened and the damper D4 is closed. The damper D5 is opened and the valve B1 is closed. The blower A2 is operated to suck in the air to be treated and supply the air to the adsorption / desorption cylinder 51 via the pipe L4. The air to be treated in this embodiment is air discharged from the carbon dioxide increasing section 40. The carbon dioxide increasing section 40 contains post-activity air in which the carbon dioxide concentration has been increased by human activity. Examples of the air to be treated include post-activity air, as well as post-combustion air generated by combustion.

[0027] The concentration of carbon dioxide in the air to be treated is, for example, preferably 100 to 5000 ppm, more preferably 200 to 4000 ppm, even more preferably 300 to 3000 ppm, even more preferably 400 to 2000 ppm, particularly preferably 500 to 1500 ppm, and most preferably 600 to 1000 ppm. When the concentration of carbon dioxide in the air to be treated is equal to or higher than the lower limit, more carbon dioxide can be adsorbed by the adsorbent, and more carbon dioxide can be desorbed in the desorption step. When the concentration of carbon dioxide in the air to be treated is equal to or lower than the upper limit, the adsorption ability of the adsorbent is less likely to deteriorate. In addition, when the concentration of carbon dioxide in the air to be treated is equal to or lower than the upper limit, cleaner treated air can be discharged from the air discharge section L7.

[0028] A part or all of the carbon dioxide in the air to be treated that has come into contact with the adsorbent is adsorbed by the adsorbent in the adsorption / desorption tube 51 (adsorption step). As a result, treated air with a reduced concentration of carbon dioxide is obtained.

[0029] The treated air flows from the air discharge section L7 through the damper D5 to the pipe L11. The carbon dioxide concentration in the treated air is lower than the carbon dioxide concentration in the air to be treated. The carbon dioxide concentration in the treated air is, for example, preferably 1000 ppm or less, more preferably 800 ppm or less, and even more preferably 500 ppm or less. When the carbon dioxide concentration in the treated air is equal to or less than the above upper limit, the carbon dioxide concentration can be made to satisfy the building environmental sanitation management standard, and cleaner treated air can be supplied to the carbon dioxide increasing section 40. The lower limit of the carbon dioxide concentration in the treated air is not particularly limited, but is substantially 10 ppm, and may be 0 ppm.

[0030] The temperature inside the adsorption / desorption tube 51 in the adsorption step is, for example, preferably 0 to 60°C, more preferably 0 to 40°C, even more preferably 5 to 35°C, and particularly preferably 10 to 30°C. When the temperature inside the adsorption / desorption tube 51 is equal to or higher than the above-mentioned lower limit, treated air at a comfortable temperature can be supplied to the carbon dioxide increasing section 40. When the temperature inside the adsorption / desorption tube 51 is equal to or lower than the above-mentioned upper limit, the adsorption ability of the adsorbent can be further improved. The temperature inside the adsorption / desorption tube 51 can be adjusted by a cooling device or the like (not shown) introduced inside the adsorption / desorption tube 51.

[0031] The pressure inside the adsorption / desorption cylinder 51 in the adsorption step is not particularly limited, but is, for example, normal pressure. In this specification, the term "normal pressure" refers to pressure when no particular reduced or increased pressure is applied, for example, 0.1 MPa.

[0032] Next, damper D3 is closed and damper D4 is opened. Damper D6 is opened and valve B2 is closed. Blower A2 is operated to suck in the air to be treated and supply the air to be treated to adsorption / desorption cylinder 52 via pipe L4. The air to be treated is the same as the air to be treated supplied to adsorption / desorption cylinder 51. A part or all of the carbon dioxide in the air to be treated that has come into contact with the adsorbent is adsorbed by the adsorbent in the adsorption / desorption tube 52 (adsorption step). As a result, treated air with a reduced concentration of carbon dioxide is obtained. The treated air flows from the air discharge section L8 through a damper D6 to a pipe L11. The carbon dioxide concentration in the treated air is the same as that of the treated air that has passed through the adsorption / desorption cylinder 51, and flowed from the air discharge part L7 through the damper D5 to the pipe L11.

[0033] The temperature inside the adsorption / desorption cylinder 52 in the adsorption step is the same as the temperature inside the adsorption / desorption cylinder 51. The temperature inside the adsorption / desorption cylinder 52 in the adsorption step may be the same as the temperature inside the adsorption / desorption cylinder 51, or may be different. The internal pressure of the adsorption / desorption cylinder 52 in the adsorption step is the same as the internal pressure of the adsorption / desorption cylinder 51. The internal pressure of the adsorption / desorption cylinder 52 in the adsorption step may be the same as the internal pressure of the adsorption / desorption cylinder 51, or may be different.

[0034] <Desorption process> While the carbon dioxide is being adsorbed in the adsorption / desorption tube 52, the damper D5 is closed and the valve B1 is opened. The pump P1 is operated to reduce the pressure inside the adsorption / desorption tube 51. When the pressure inside the adsorption / desorption tube 51 is reduced, the carbon dioxide adsorbed to the adsorbent inside the adsorption / desorption tube 51 is desorbed due to the pressure difference (desorption step). The desorbed carbon dioxide is supplied from the carbon dioxide discharge part L9 via the branch 103 to the pipe L12.

[0035] The internal pressure of the adsorption / desorption tube 51 in the desorption step is preferably lower than normal pressure. The internal pressure of the adsorption / desorption tube 51 in the desorption step is, for example, preferably 100 kPa or less, more preferably 100 Pa or less, and even more preferably 0.1 Pa or less. When the internal pressure of the adsorption / desorption tube 51 in the desorption step is equal to or less than the above upper limit, a larger amount of carbon dioxide can be desorbed more easily. The lower limit of the pressure inside the adsorption / desorption cylinder 51 in the desorption step is preferably as low as possible. In theory, it is an absolute vacuum (0 Pa), but in practice, it is an ultra-high vacuum (10 -5 Pa or less). The principle of desorbing carbon dioxide using the pressure difference in the desorption process is also called pressure swing adsorption (PSA). The principle of desorbing carbon dioxide by lowering the internal pressure of the adsorption / desorption tube 51 to 100 kPa or less in the desorption step is also called vacuum swing adsorption (VSA).

[0036] In the adsorption / desorption cylinder 51, the partial pressure of carbon dioxide may be reduced to desorb the carbon dioxide adsorbed to the adsorbent. In this case, the partial pressure of carbon dioxide is, for example, preferably 40 Pa or less, more preferably 20 Pa or less, and even more preferably 10 Pa or less. When the partial pressure of carbon dioxide is equal to or less than the above upper limit, a larger amount of carbon dioxide can be desorbed more easily. The lower limit of the partial pressure of carbon dioxide is not particularly limited, but may be, for example, 0.1 Pa. The partial pressure of carbon dioxide is obtained by measuring the concentration of carbon dioxide inside the adsorption / desorption cylinder 51 . Methods for lowering the partial pressure of carbon dioxide include a method of reducing the pressure inside the adsorption / desorption tube 51, and a method of supplying a gas other than carbon dioxide to the adsorption / desorption tube 51. Examples of gas other than carbon dioxide include helium gas, hydrogen gas, argon gas, outside air, and air discharged from the room. Since it can be discharged outside the system, outside air and air discharged from the room are preferable as gas other than carbon dioxide, and outside air is more preferable.

[0037] When the carbon dioxide adsorbed to the adsorbent in the adsorption / desorption tube 51 has been sufficiently desorbed, the valve B1 is closed and the dampers D3 and D5 are opened. The pressure inside the adsorption / desorption tube 51 returns to normal pressure, and the air to be treated flows in. Some or all of the carbon dioxide in the air to be treated comes into contact with the adsorbent and is adsorbed by the adsorbent in the adsorption / desorption tube 51. The treated air, with its reduced carbon dioxide concentration, flows from the air discharge part L7 through the damper D5 to the pipe L11.

[0038] While carbon dioxide is being adsorbed in the adsorption / desorption tube 51, the dampers D4 and D6 are closed and the valve B2 is opened. The pump P1 is operated to reduce the pressure inside the adsorption / desorption tube 52. When the pressure inside the adsorption / desorption tube 52 is reduced, the carbon dioxide adsorbed to the adsorbent inside the adsorption / desorption tube 52 is desorbed due to the pressure difference (desorption step). The desorbed carbon dioxide is supplied from the carbon dioxide discharge section L10 via the branch 103 to the pipe L12. When a building air conditioning system (for the entire building and all floors) is used, which will be described later, the pump P1 may be in a constant operating state.

[0039] The internal pressure of the adsorption / desorption tube 52 in the desorption process is the same as the internal pressure of the adsorption / desorption tube 51 in the desorption process. The internal pressure of the adsorption / desorption tube 52 in the desorption process may be the same as or different from the internal pressure of the adsorption / desorption tube 51 in the desorption process.

[0040] In the adsorption / desorption cylinder 52, the partial pressure of carbon dioxide may be reduced to desorb the carbon dioxide adsorbed to the adsorbent. In this case, the partial pressure of carbon dioxide is the same as that in the adsorption / desorption tube 51. The partial pressure of carbon dioxide in the adsorption / desorption tube 52 may be the same as the partial pressure of carbon dioxide in the adsorption / desorption tube 51, or may be different. The method of reducing the partial pressure of carbon dioxide in the adsorption / desorption tube 52 is the same as that in the adsorption / desorption tube 51. When a gas other than carbon dioxide is supplied to the adsorption / desorption tube 52, the type of the gas other than carbon dioxide is the same as that in the adsorption / desorption tube 51.

[0041] In this embodiment, the adsorption / desorption tube 51 and the adsorption / desorption tube 52 are arranged in parallel, so that the flow of the air to be treated and the discharge of carbon dioxide can be performed simultaneously. Therefore, the air to be treated can be treated continuously, and the efficiency of the treatment of the air to be treated can be further improved. In addition, carbon dioxide can be supplied stably. In this embodiment, it is possible to alternate between the adsorption process and the desorption process by controlling the opening and closing of dampers and valves. In this embodiment, the air to be treated (return air) having a high carbon dioxide concentration, which is discharged from the carbon dioxide increasing section 40, can be supplied to the adsorption / desorption columns 51 and 52. This makes it easier to adsorb a larger amount of carbon dioxide into the adsorbent.

[0042] The treated air that has flowed into the pipe L11 is discharged outside the air conditioning system 1 by opening the damper D7. The treated air that has flowed into the pipe L11 is supplied to the mixer 20 via the branch 104 and the pipe L13 by closing the damper D7 and opening the damper D8.

[0043] By opening the damper D1, outside air is supplied from the air supply unit 10 to the mixer 20 via the pipes L0 and L1.

[0044] In the mixer 20, the outside air and the treated air are mixed to form a mixed fluid. By providing the mixing section 20, the amount of outside air introduced from the air supply section 10 can be reduced, and the air conditioning load due to the outside air load can be reduced. In this embodiment, the mixer 20 is located after the adsorption / desorption section 50. Therefore, a mixed fluid with a reduced carbon dioxide concentration is obtained. The mixed fluid is supplied to the air conditioning unit 30 via the pipe L2.

[0045] The carbon dioxide concentration in the mixed fluid is, for example, preferably 100 to 5000 ppm, more preferably 200 to 4000 ppm, even more preferably 300 to 3000 ppm, even more preferably 400 to 2000 ppm, particularly preferably 500 to 1500 ppm, and most preferably 600 to 1000 ppm. When the carbon dioxide concentration in the mixed fluid is equal to or higher than the lower limit, more carbon dioxide can be adsorbed by the adsorbent, and more carbon dioxide can be desorbed in the desorption step. When the carbon dioxide concentration in the mixed fluid is equal to or lower than the upper limit, cleaner air can be supplied to the carbon dioxide increasing section 40.

[0046] The mixed fluid supplied to the air conditioning unit 30 has dust and other contaminants removed by the filter 32, and then the temperature and humidity are adjusted within the air conditioning unit 30. The mixed fluid whose temperature and humidity have been adjusted is supplied as clean air to the carbon dioxide increase unit 40 via the pipe L3 and the air intakes 41 and 42 by operating the blower A1.

[0047] The temperature inside the air conditioning unit 30 is not particularly limited, but is preferably 0 to 60°C, more preferably 0 to 40°C, further preferably 5 to 35°C, and particularly preferably 10 to 30°C, for example. When the temperature inside the air conditioning section 30 is within the above numerical range, air at a comfortable temperature can be supplied to the carbon dioxide increasing section 40 . The temperature inside the air conditioning unit 30 can be adjusted by, for example, a heater (not shown) or a refrigerant.

[0048] The humidity inside the air conditioning unit 30 is not particularly limited, but is preferably 5 to 95% RH, more preferably 10 to 80% RH, and even more preferably 20 to 70% RH. If the humidity inside the air conditioning unit 30 is within the above numerical range, the humidity inside the carbon dioxide increasing unit 40 can be made more comfortable. The humidity inside the air conditioning unit 30 can be adjusted by, for example, a humidifier or a dehumidifier.

[0049] The mixed fluid supplied to the carbon dioxide increasing section 40 has its carbon dioxide concentration increased, for example, by human activity, and is then supplied as the air to be treated from the exhaust port 43 through the pipe L4 to the adsorption / desorption section 50.

[0050] In this embodiment, the adsorption / desorption section 50 is located after the carbon dioxide increase section 40. Therefore, the air to be treated with an increased carbon dioxide concentration can be supplied to the adsorption / desorption section 50. As a result, more carbon dioxide can be adsorbed by the adsorbent in the adsorption / desorption tubes 51 and 52. In addition, the post-activity air (air to be treated) is no longer simply discharged outdoors as was the case in the past, and carbon dioxide emissions can be reduced.

[0051] <Recovery process> The carbon dioxide supplied to the pipe L12 is supplied to the recovery section 60 via the branch 105 and the pipe L14 (recovery step). At this time, the carbon dioxide may be merged with carbon dioxide discharged from another air conditioning system and passed through the pipe L14.

[0052] The captured carbon dioxide is stored in a cylinder or the like and can be effectively reused as a carbon source (carbon recycling). In this way, the recovery step can recover carbon dioxide with a higher concentration.

[0053] The concentration of the recovered carbon dioxide may be, for example, 1000 ppm or more, preferably 1000 to 750000 ppm, 1000 to 500000 ppm, 1000 to 250000 ppm, 1000 to 100000 ppm, more preferably 1000 to 10000 ppm, further preferably 2000 to 10000 ppm, and particularly preferably 2000 to 5000 ppm. When the concentration of the recovered carbon dioxide is equal to or higher than the lower limit, more carbon dioxide can be effectively used. When the concentration of the recovered carbon dioxide is equal to or lower than the upper limit, management becomes easier. The concentration of the recovered carbon dioxide can be adjusted by the type and amount of the adsorbent, the internal pressure of the adsorption / desorption unit 50, the internal temperature of the adsorption / desorption unit 50, the time in the desorption step, and combinations of these.

[0054] In this embodiment, the desorption process using a pressure difference has been described, but the present invention is not limited to the above embodiment. The desorption step may be performed based on the principle of temperature swing adsorption (TSA) using a temperature difference, or may be performed based on both a pressure difference and a temperature difference. By desorption due to both pressure difference and temperature difference, carbon dioxide can be desorbed more efficiently. The temperature difference is, for example, preferably 10 to 200°C, more preferably 20 to 180°C, and even more preferably 30 to 160°C. When the temperature difference is equal to or greater than the lower limit, a larger amount of carbon dioxide can be desorbed. When the temperature difference is equal to or less than the upper limit, deterioration of the adsorbent can be suppressed. In addition, energy can be saved.

[0055] <Building air conditioning system> The building air conditioning system of the present invention is provided with a plurality of the above-mentioned air conditioning systems on different floors. In the building air conditioning system, it is sufficient for one floor to have one or more air conditioning systems of the present invention. For example, by installing air conditioning systems on two or more floors, the amount of carbon dioxide captured can be increased. In this case, the carbon dioxide emitted from the air conditioning systems on different floors can be stored on each floor, or it can be stored together in one place. The amount of carbon dioxide that can be stored can be increased according to the number of air conditioning systems.

[0056] The present invention will be described below by taking an example of a building air conditioning system. The building air conditioning system 200 in FIG. 2 has a plurality of air conditioning units 210, a carbon dioxide exhaust section L20, a pipe L21, and a recovery section 60. The air conditioning units 210 are provided on each ground floor A of the building 201. The piping L21 extends vertically within the building 201, reaching from the top floor above ground to the basement floor B. The piping L21 is connected to the recovery section 60 on the basement floor B via a vacuum pump 212. The air conditioning units 210 on each ground floor A are connected to the piping L21 via a carbon dioxide exhaust section L20. The carbon dioxide discharge part L20 may be, for example, the same pipe as the carbon dioxide discharge parts L9 and L10. The pipe L21 may be, for example, a duct similar to the pipe L14.

[0057] The air conditioning unit 210 is a device in which the pipe L12, the pipe L14, and the recovery section 60 in the air conditioning system 1 of FIG.

[0058] In the building air conditioning system 200 of this embodiment, carbon dioxide discharged from the air conditioning units 210 on each upper floor A flows through the carbon dioxide discharge section L20 and reaches the pipe L21. The carbon dioxide that has reached the pipe L21 flows down the pipe L21 and is filled into the recovery section 60 by the vacuum pump 212. In this way, by capturing carbon dioxide on each floor and collecting it, more carbon dioxide can be captured.

[0059] As described above, the air conditioning system of the present embodiment can remove carbon dioxide from the outside air and the air in the room. Therefore, treated air with a reduced carbon dioxide concentration can be supplied to the room. According to the air conditioning system of the present embodiment, the removed carbon dioxide can be recovered. Therefore, the recovered carbon dioxide can be used as an energy source such as a carbon source. According to the air conditioning system of the present embodiment, the treated air can be circulated and reused, so there is no need to rely on outside air to supply air to rooms. This reduces the outside air load, which is said to account for 40% of the air conditioning load. According to the air conditioning system of the present embodiment, the air conditioning load can be reduced, which in turn reduces the air conditioning cost and the energy required for air conditioning, which leads to a reduction in carbon dioxide emissions from the power plant. According to the air conditioning system of this embodiment, since it can directly capture carbon dioxide from the outside air, if it is widely used, it will lead to a reduction in carbon dioxide emissions worldwide. In addition, since it can directly capture carbon dioxide from the outside air, it can capture carbon dioxide in large quantities and stably compared to conventional technologies that absorb carbon dioxide only from indoor exhaust. The carbon dioxide adsorbed and captured by the air conditioning system, building air conditioning system, or carbon dioxide capture method of this embodiment can be stably supplied in the amount necessary for industrial use. Therefore, the captured carbon dioxide is suitable as a material for synthesizing C1 compounds such as carbon monoxide, methane, methanol, and formic acid, a material for synthesizing C2 compounds such as ethane, ethylene, and ethanol, or a material for synthesizing olefin compounds such as propylene and butene, by chemical engineering processes such as artificial photosynthesis. In this way, the technology of the present invention is beneficial to the global environment.

[0060] Although the preferred embodiment of the present invention has been described in detail above, the present invention is not limited to such a specific embodiment, and various modifications are possible within the scope of the gist of the present invention described in the claims.

[0061] In the above embodiment, two adsorption / desorption cylinders are provided, but the present invention is not limited to this. For example, the number of adsorption / desorption cylinders may be one, or three or more. When the number of the adsorption / desorption cylinders is one, the adsorption and desorption of carbon dioxide can be performed in one adsorption / desorption cylinder. When the number of adsorption / desorption cylinders is three or more, carbon dioxide adsorption can be performed in any of the adsorption / desorption cylinders, and carbon dioxide desorption can be performed in any of the other adsorption / desorption cylinders. After switching between adsorption and desorption of carbon dioxide, carbon dioxide desorption can be performed in any of the adsorption / desorption cylinders, and carbon dioxide adsorption can be performed in any of the other adsorption / desorption cylinders. The number of the optional adsorption / desorption cylinders and the number of the other optional adsorption / desorption cylinders are not particularly limited, but considering the balance between adsorption and desorption of carbon dioxide, it is preferable that the number of the optional adsorption / desorption cylinders is equal to the number of the other optional adsorption / desorption cylinders. The number of adsorption / desorption cylinders is preferably two, since this allows the air conditioning system to be made more compact.

[0062] In the above-described embodiment, the adsorption / desorption unit has an adsorption / desorption tube, but the adsorption / desorption unit may not have an adsorption / desorption tube and may be, for example, an apparatus such as an air handling unit having a regeneration zone and a treatment zone. In the above embodiment, the carbon dioxide increase section 40 has two air inlets, but the number of air inlets may be one, or three or more. In the above embodiment, the carbon dioxide increase section 40 has one exhaust port, but the number of exhaust ports may be two or more. In the above embodiment, one air conditioning system is installed on one floor, but the number of air conditioning systems on one floor may be two or more. [Explanation of symbols]

[0063] 1...air conditioning system, 10...air supply section, 12...outdoor air intake, A1, A2...blower, 2 0...mixing section, 30...air conditioning section, 32...filter, 40...carbon dioxide increase section, 41,4 2...air inlet, 43...exhaust port, 50...adsorption / desorption section, 51, 52...adsorption / desorption tube, 60...recovery section, D 1, D3, D4, D5, D6, D7, D8…Damper, L7, L8…Air exhaust section, L9, L 10,L20...Carbon dioxide discharge part, L0,L1,L2,L3,L4,L5,L6,L11 ,L12,L13,L14,L21...piping, P1...pump, 101,102,103,1 04,105…Branch, 200…Building air conditioning system, 201…Building, 210…Air conditioning unit 212...Vacuum pump

Claims

1. An air conditioning system that captures carbon dioxide and reuses the captured carbon dioxide, The system includes a carbon dioxide increasing section in which the concentration of carbon dioxide increases, an air supply section that supplies outside air to the carbon dioxide increasing section, a mixing section, an air conditioning section, an adsorption / desorption section, and a recovery section, The mixing section is located downstream of the adsorption / desorption section, The adsorption / desorption unit has an adsorbent having a carbon dioxide adsorption ability, The adsorption / desorption unit has two or more adsorption / desorption cylinders filled with the adsorbent, Two or more of the adsorption / desorption tubes are arranged in parallel, and air flow rate regulators are provided before and after the adsorption / desorption tubes, air to be treated that contains carbon dioxide is supplied from the carbon dioxide increasing section to the adsorption / desorption section, and adsorption of the carbon dioxide and desorption of the carbon dioxide are alternately switched between any one of the adsorption / desorption tubes and any other one of the adsorption / desorption tubes, and the air to be treated is brought into contact with the adsorbent in any one of the adsorption / desorption tubes, thereby adsorbing part or all of the carbon dioxide from the air to be treated onto the adsorbent to obtain treated air, the treated air is discharged from the adsorption / desorption section, and the treated air is supplied to the mixing section, The carbon dioxide adsorbed to the adsorbent is desorbed, the desorbed carbon dioxide is discharged from the adsorption / desorption section, and the carbon dioxide is supplied to the recovery section; The treated air discharged from the adsorption / desorption unit and the outside air supplied from the air supply unit are mixed in the mixing unit to obtain a mixed fluid; an air conditioning unit that purifies the mixed fluid supplied from the mixing unit and adjusts the temperature, and then supplies the mixed fluid from the air conditioning unit to the carbon dioxide increasing unit.

2. The air conditioning system according to claim 1 , wherein the adsorption / desorption unit desorbs the carbon dioxide adsorbed to the adsorbent by reducing an internal pressure.

3. A building air conditioning system comprising a plurality of the air conditioning systems according to claim 1 or 2 on different floors.

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