Air conditioning system

Abstract

To provide an air conditioning system which recovers carbon dioxide, and can effectively utilize the recovered carbon dioxide.SOLUTION: An air conditioning system 1 has a carbon dioxide increase part 40 in which a concentration of carbon dioxide increases, an adsorption / desorption part 50, and a recover part 60. The adsorption / desorption part 50 has an adsorbent with carbon dioxide adsorption capacity. According to this system, processing object air containing carbon dioxide is supplied to the adsorption / desorption part 50 from the carbon dioxide increase part 40 and the processing object air is brought into contact with the adsorbent, whereby a part or all of carbon dioxide is adsorbed to the adsorbent from the processing object air to produce processed air, the processed air is discharged from the adsorption / desorption part 50, carbon dioxide adsorbed to the adsorbent is desorbed, the desorbed carbon dioxide is discharged from the adsorption / desorption part 50, and is supplied to the recovery part 60.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an air conditioning system to the mud .

Background Art

[0002] In the building environmental sanitation management standards, it is stipulated that in a living room where air conditioning equipment is installed, the carbon dioxide content should be 1000 ppm or less (volume basis; the same shall apply hereinafter in this specification). Thus, in the interior of a building equipped with air conditioning equipment, a technique for removing carbon dioxide from the indoor air is desired.

[0003] For example, Patent Document 1 discloses a rotor divided into a treatment zone for absorbing air to be treated containing carbon dioxide into an amine-supported solid absorbent and a regeneration zone for desorbing the carbon dioxide absorbed by the absorbent into regeneration air, and an air conditioning system configured such that the enthalpy difference between the air to be treated supplied to the treatment zone and the regeneration air supplied to the regeneration zone is within a specific range. According to the invention of Patent Document 1, it is intended to remove carbon dioxide in the indoor air and improve the air quality.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, carbon dioxide can be used for the production of valuable substances by being recovered by an appropriate method. However, in the technique of Patent Document 1, the removed carbon dioxide is discharged outdoors, and no consideration is given to recovering carbon dioxide.

[0006] Therefore, an object of the present invention is to provide an air conditioning system, a building air conditioning system, and a carbon dioxide recovery method in a building that can recover carbon dioxide and effectively utilize the recovered carbon dioxide.

Means for Solving the Problems

[0007] In order to solve the above problems, the present invention has the following aspects. [1] An air conditioning system that recovers carbon dioxide and reuses the recovered carbon dioxide, comprising: a carbon dioxide increasing part where the concentration of carbon dioxide increases, an air supply part that supplies outside air to the carbon dioxide increasing part, a mixing part, an air conditioning part, an adsorption / desorption part, and a recovery part; the mixing part is located downstream of the adsorption / desorption part; the adsorption / desorption part includes a first adsorption / desorption cylinder that adsorbs carbon dioxide, or attachment / detachment a second adsorption / desorption cylinder that desorbs carbon dioxide, and an adsorbent carried on the first adsorption / desorption cylinder and the second adsorption / desorption cylinder and having carbon dioxide adsorption ability; adsorption or while adsorbing carbon dioxide in the first adsorption / desorption cylinder, desorb carbon dioxide in the second adsorption / desorption cylinder, while adsorbing carbon dioxide in the second adsorption / desorption cylinder, desorb carbon dioxide in the first adsorption / desorption cylinder, Treating air to be processed containing carbon dioxide is supplied from the carbon dioxide increasing part to the adsorption / desorption part, and the air to be processed is brought into contact with the adsorbent, so that part or all of the carbon dioxide in the air to be processed is adsorbed by the adsorbent to obtain treated air. The treated air is discharged from the adsorption / desorption part and supplied to the mixing part. The first adsorption / desorption cylinder and The second adsorption / desorption cylinder is , reduce the internal pressure or lower the partial pressure of carbon dioxide By doing so, the carbon dioxide adsorbed on the adsorbent is desorbed, and the desorbed carbon dioxide is discharged from the adsorption / desorption part of two and supplied to the recovery part. two The treated air discharged from the adsorption / desorption part and the outside air supplied from the air supply part are mixed in the mixing part to form a mixed fluid. two by , the recovery unit recovers carbon dioxide and uses the recovered carbon dioxide as a carbon source, An air conditioning system that cleans the mixed fluid supplied from the mixing section in the air conditioning section, adjusts the temperature, and then supplies the mixed fluid from the air conditioning section to the carbon dioxide increasing section.

Advantages of the Invention

[0009] According to the air conditioning system, building air conditioning system, and carbon dioxide recovery method of the present invention, in an air conditioning system in a building, carbon dioxide can be recovered and the recovered carbon dioxide can be effectively utilized.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0011] ≪Air Conditioning System≫ The air conditioning system of the present invention includes a carbon dioxide increasing section where 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. Hereinafter, an air conditioning system according to an embodiment of the present invention will be described in detail with reference to FIG. 1.

[0012] As shown in FIG. 1, the air conditioning system 1 of the present embodiment includes 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 increasing unit 40 are connected by a pipe L3. A pipe L4 is connected to the carbon dioxide increasing unit 40. The pipe L4 is connected to the adsorption / desorption unit 50 at a branch 101. A blower A2 is provided in the pipe L4. 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 represent the moving direction of fluids such as air.

[0013] <Air supply unit> The air supply unit 10 supplies outside air to the carbon dioxide increasing unit 40. The air supply unit 10 of the present embodiment includes 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 mixing unit 20 via the pipe L1. For example, a blower (fan) or the like that gives energy to the gas by the rotational movement of an impeller may be provided in the pipes L0 and L1.

[0014] Examples of the outside air intake 12 include a gallery or the like with a rain cover or the like that can introduce outside air and prevent the intrusion of rainwater. Examples of the damper D1 include an air volume regulator that can adjust the flow rate by opening and closing a valve, a fire damper having a fire spread prevention function for use in an opening portion facing the outer wall, and the like. Examples of the pipe L0 include a duct made of metal or resin. Examples of the pipe L1 include a duct similar to the pipe L0.

[0015] <Mixing unit> The mixing unit 20 mixes outside air and treated air. Examples of the mixing unit 20 include a chamber made of metal or resin. As the pipe L2, ducts or the like similar to the pipe L0 can be mentioned.

[0016] <Air conditioning unit> The air conditioning unit 30 cleans the mixed fluid of outside air and treated air, adjusts the temperature, and then supplies the mixed fluid to the carbon dioxide increasing section 40. The air conditioning unit 30 includes a filter 32 and a blower A1. As the air conditioning unit 30, for example, devices such as an air handling unit (AHU) can be mentioned. As the filter 32, for example, filters or the like that can remove dust in the atmosphere can be mentioned. As the blower A1, for example, blowers or the like that give energy to the gas by the rotational motion of the impeller can be mentioned.

[0017] <Carbon dioxide increasing section> As the carbon dioxide increasing section 40, for example, living rooms where people are active indoors such as offices can be mentioned. In the carbon dioxide increasing section 40, the concentration of carbon dioxide increases as people breathe. In addition, as the carbon dioxide increasing section 40, for example, rooms equipped with combustion-type heaters, firing devices, etc. can be mentioned. In this specification, the carbon dioxide increasing 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 increasing section 40 shall include moments when the concentration of carbon dioxide decreases. The carbon dioxide increasing section 40 has air supply ports 41, 42 and an exhaust port 43. A pipe L3 is connected to the air supply ports 41 and 42. A pipe L4 is connected to the exhaust port 43. As the air supply ports 41, 42, for example, air vents made of metal or resin can be mentioned. As the exhaust port 43, for example, air vents made of metal or resin can be mentioned. As the pipe L4, for example, return air ducts made of metal or resin can be mentioned.

[0018] <Adsorption and desorption section> The adsorption / desorption section 50 includes two adsorption / desorption cylinders 51, 52, pipes L5, L6, air discharge sections L7, L8, dampers D3 to D6, and carbon dioxide discharge sections L9, 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 hand and desorbed on the other hand. In this specification, "adsorption" means that a liquid or gas is adsorbed on the surface of another solid or liquid. "Desorption" means that the adsorbed substance leaves the adsorption interface. It is also called desorption. "Adsorption / desorption" means both or either one of adsorption and desorption. The pipe L5 is provided with a damper D3. The pipe L6 is provided with a damper D4. The air discharge section L7 is provided with a damper D5. The air discharge section L8 is provided with a damper D6. That is, dampers are provided before and after the adsorption / desorption cylinders 51, 52. The pipe L5 and the pipe L6 are connected by a branch 101. The air discharge section L7 and the air discharge section L8 are connected by a branch 102. The carbon dioxide discharge section L9 is provided with a valve B1. The carbon dioxide discharge section L10 is provided with a valve B2. The dampers D3 to D6, the valves B1, B2 are connected to the control unit C1. The adsorption / desorption cylinders 51, 52 are filled with an adsorbent having carbon dioxide adsorption ability. The adsorption / desorption cylinders 51, 52 are cylindrical members capable of supporting the adsorbent. Examples of the adsorption / desorption cylinders 51, 52 include cylindrical members made of metal or resin, and cylindrical members obtained by corrugating (rippling) incombustible sheets such as ceramic fiber paper and glass fiber paper. The adsorbent is not particularly limited as long as it has carbon dioxide adsorption ability. Examples of the adsorbent include zeolite, silica gel, activated carbon, solid absorbents carrying amines such as triethanolamine and monoethanolamine, and amine-based weakly basic anion exchange resins. As the adsorbent, zeolite, silica gel, and activated carbon are preferred, and zeolite and silica gel are more preferred.

[0019] Examples of the dampers D3, D4, D5, and D6 include air volume regulators that can be controlled to open and close by the control unit C1. Examples of the valves B1 and B2 include solenoid valves that can be controlled to open and close by the control unit C1. Examples of the control unit C1 include a computer that can adjust the opening and closing of the dampers D3, D4, D5, D6, and the valves B1 and B2. By adjusting the opening and closing of the dampers D3, D4, D5, D6, and the valves B1 and B2 with the control unit C1, the adsorption of carbon dioxide and the desorption of carbon dioxide can be controlled to be alternately switched between the adsorption / desorption cylinder 51 and the adsorption / desorption cylinder 52.

[0020] Examples of the pipe L5 include ducts similar to the pipe L0. Examples of the pipe L6 include ducts similar to the pipe L0.

[0021] The air discharge parts L7 and L8 discharge the treated air in which part or all of the carbon dioxide has been adsorbed by the adsorbent from the air to be treated. Examples of the air discharge parts L7 and L8 include ducts made of metal or resin. A blower, a suction pump, or the like may be provided in the air discharge parts L7 and L8. The air discharge parts L7 and L8 of the present embodiment are connected to the pipe L11 at the branch 102. A damper D7 is provided in the pipe L11. The pipe L11 is connected to the pipe L13 at the branch 104. A damper D8 is provided in the pipe L13. Examples of the pipe L11 include ducts similar to the pipe L0. Examples of the pipe L13 include ducts similar to the pipe L0. Examples of the damper D7 include air volume regulators that can adjust the flow rate by opening and closing the valve. As the damper D8, an air volume regulator or the like similar to the damper D7 can be mentioned. 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. As the carbon dioxide discharge parts L9 and L10, for example, pipes made of metal or resin can be mentioned. The carbon dioxide discharge parts L9 and L10 may be provided with a blower, a suction pump or the like. The carbon dioxide discharge parts L9 and L10 of the present embodiment are connected to the pipe L12 at the branch 103. The pipe L12 is connected to the pipe L14 at the branch 105. A pump P1 is provided in the pipe L14. As the pipe L12, a duct or the like similar to the pipe L0 can be mentioned. As the pipe L14, a duct or the like similar to the pipe L0 can be mentioned. As the pump P1, a vacuum pump, a suction pump or the like can be mentioned.

[0023] <Recovery section> One end of the pipe L14 is connected to the recovery section 60. The other end of the pipe L14 is connected to, for example, the carbon dioxide discharge part of another air conditioning system (not shown). The carbon dioxide desorbed from the adsorbent is supplied to the recovery section 60. As the recovery section 60, for example, a container such as a tank capable of storing carbon dioxide can be mentioned.

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

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

[0026] In the adsorption process, 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 the air to be treated, and the air to be treated is supplied to the adsorption / desorption cylinder 51 via the pipe L4. The air to be treated in the present embodiment is the air discharged from the carbon dioxide increasing section 40. In the carbon dioxide increasing section 40, the post-activity air with an increased carbon dioxide concentration due to human activities is included. Examples of the air to be treated include, in addition to the post-activity air, the post-combustion air generated by combustion, etc.

[0027] The concentration of carbon dioxide in the air to be treated is preferably, for example, 100 to 5000 ppm, more preferably 200 to 4000 ppm, still more preferably 300 to 3000 ppm, still 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 above lower limit value, more carbon dioxide can be adsorbed by the adsorbent, and more carbon dioxide can be desorbed in the desorption process. When the concentration of carbon dioxide in the air to be treated is equal to or lower than the above upper limit value, it is difficult to deteriorate the adsorption capacity of the adsorbent. In addition, when the concentration of carbon dioxide in the air to be treated is equal to or lower than the above upper limit value, cleaner treated air can be discharged from the air discharge section L7.

[0028] 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 cylinder 51 (adsorption process). As a result, treated air with a reduced carbon dioxide concentration is obtained.

[0029] The treated air flows from the air discharge section L7 to the pipe L11 via the damper D5. The carbon dioxide concentration in the treated air is lower than that in the air to be treated. The carbon dioxide concentration in the treated air is preferably, for example, 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 below the above upper limit value, the carbon dioxide concentration that meets the building environmental sanitation management standards can be achieved, and cleaner treated air can be supplied to the carbon dioxide increasing section 40. The lower limit value 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 cylinder 51 in the adsorption process is preferably, for example, 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 cylinder 51 is above the above lower limit value, treated air at a comfortable temperature can be supplied to the carbon dioxide increasing section 40. When the temperature inside the adsorption / desorption cylinder 51 is below the above upper limit value, the adsorption capacity of the adsorbent can be further enhanced. The temperature inside the adsorption / desorption cylinder 51 can be adjusted by introducing a cooling device or the like (not shown) inside the adsorption / desorption cylinder 51 and using that cooling device.

[0031] The pressure inside the adsorption / desorption cylinder 51 in the adsorption process is not particularly limited, but is, for example, normal pressure. In this specification, "normal pressure" refers to the pressure when neither special decompression nor pressurization is performed, and is, for example, 0.1 MPa.

[0032] Next, the damper D3 is closed and the damper D4 is opened. The damper D6 is opened and the valve B2 is closed. The blower A2 is operated to suck the air to be treated, and the air to be treated is supplied to the adsorption / desorption cylinder 52 via the pipe L4. The air to be treated is the same as the air to be treated supplied to the adsorption / desorption cylinder 51. 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 cylinder 52 (adsorption process). As a result, treated air with a reduced carbon dioxide concentration is obtained. The treated air flows from the air discharge section L8 to the pipe L11 via the damper D6. The carbon dioxide concentration in the processed air is the same as that of the processed 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 process is the same as the temperature inside the adsorption / desorption cylinder 51. The temperature inside the adsorption / desorption cylinder 52 in the adsorption process may be the same as or different from the temperature inside the adsorption / desorption cylinder 51. The pressure inside the adsorption / desorption cylinder 52 in the adsorption process is the same as the pressure inside the adsorption / desorption cylinder 51. The pressure inside the adsorption / desorption cylinder 52 in the adsorption process may be the same as or different from the pressure inside the adsorption / desorption cylinder 51.

[0034] <Desorption process> While the adsorption / desorption cylinder 52 is adsorbing carbon dioxide, close the damper D5 and open the valve B1. Operate the pump P1 to reduce the pressure inside the adsorption / desorption cylinder 51. When the pressure inside the adsorption / desorption cylinder 51 is reduced, due to the pressure difference, the carbon dioxide adsorbed on the adsorbent inside the adsorption / desorption cylinder 51 is desorbed (desorption process). The desorbed carbon dioxide is supplied from the carbon dioxide discharge part L9 through the branch 103 to the pipe L12.

[0035] The pressure inside the adsorption / desorption cylinder 51 in the desorption process is preferably lower than the atmospheric pressure. For example, the pressure inside the adsorption / desorption cylinder 51 in the desorption process is preferably 100 kPa or less, more preferably 100 Pa or less, and even more preferably 0.1 Pa or less. When the pressure inside the adsorption / desorption cylinder 51 in the desorption process is below the above upper limit value, more carbon dioxide can be desorbed more easily. The lower the lower limit value of the pressure inside the adsorption / desorption cylinder 51 in the desorption process, the more preferable it is. In theory, it is absolute vacuum (0 Pa), but substantially, it is ultra-high vacuum (10 -5 Pa or less). Note that the principle of desorbing carbon dioxide by utilizing the pressure difference in the desorption process is also called pressure swing adsorption (PSA). The principle of reducing the pressure inside the adsorption / desorption cylinder 51 to 100 kPa or less in the desorption process to desorb carbon dioxide is also called vacuum swing adsorption (VSA).

[0036] In the adsorption / desorption cylinder 51, the carbon dioxide adsorbed on the adsorbent may be desorbed by reducing the partial pressure of carbon dioxide. In this case, the partial pressure of carbon dioxide is preferably, for example, 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 lower than the above upper limit value, more carbon dioxide can be more easily desorbed. The lower limit value of the partial pressure of carbon dioxide is not particularly limited, and for example, 0.1 Pa can be mentioned. The partial pressure of carbon dioxide is obtained by measuring the concentration of carbon dioxide inside the adsorption / desorption cylinder 51. As a method for reducing the partial pressure of carbon dioxide, in addition to the method of reducing the pressure inside the adsorption / desorption cylinder 51, there is a method of supplying a gas other than carbon dioxide to the adsorption / desorption cylinder 51. Examples of the 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 to the outside of the system, as the gas other than carbon dioxide, outside air or air discharged from the room is preferable, and outside air is more preferable.

[0037] When the carbon dioxide adsorbed on the adsorbent in the adsorption / desorption cylinder 51 is sufficiently desorbed, the valve B1 is closed and the dampers D3 and D5 are opened. The pressure inside the adsorption / desorption cylinder 51 returns to normal pressure, and the air to be treated flows in. Part 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 cylinder 51. The treated air with a reduced carbon dioxide concentration flows from the air discharge part L7 through the damper D5 to the pipe L11.

[0038] While the adsorption / desorption cylinder 51 is adsorbing carbon dioxide, 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 cylinder 52. When the pressure inside the adsorption / desorption cylinder 52 is reduced, the carbon dioxide adsorbed on the adsorbent in the adsorption / desorption cylinder 52 is desorbed due to the pressure difference (desorption step). The desorbed carbon dioxide is supplied from the carbon dioxide discharge part L10 through the branch 103 to the pipe L12. In the case of corresponding to the building air conditioning system (entire building, all floors) described later, the pump P1 may be in an operating state at all times.

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

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

[0041] In the present embodiment, since the adsorption / desorption cylinder 51 and the adsorption / desorption cylinder 52 are arranged in parallel, 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 continuously treated, and the efficiency of treating the air to be treated can be further improved. In addition, carbon dioxide can be stably supplied. In the present embodiment, by controlling the opening and closing of the damper and the valve, it is possible to alternately switch between the adsorption process and the desorption process. In the present embodiment, the air to be treated (return air) with a high carbon dioxide concentration discharged from the carbon dioxide increasing part 40 can be supplied to the adsorption / desorption cylinders 51 and 52. Therefore, it is possible to more easily adsorb more carbon dioxide to the adsorbent.

[0042] The treated air flowing into the pipe L11 is discharged to the outside of the system of the air conditioning system 1 by opening the damper D7. The treated air flowing into the pipe L11 is supplied to the mixing section 20 via the branch 104 and the pipe L13 by closing the damper D7 and opening the damper D8.

[0043] From the air supply section 10, outside air is supplied to the mixing section 20 via the pipes L0 and L1 by opening the damper D1.

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

[0045] The carbon dioxide concentration in the mixed fluid is preferably, for example, 100 to 5000 ppm, more preferably 200 to 4000 ppm, still more preferably 300 to 3000 ppm, still 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 above lower limit value, more carbon dioxide can be adsorbed by the adsorbent, and more carbon dioxide can be desorbed in the desorption process. When the carbon dioxide concentration in the mixed fluid is equal to or lower than the above upper limit value, cleaner air can be supplied to the carbon dioxide increasing section 40.

[0046] The mixed fluid supplied to the air conditioning section 30 is cleaned of dirt such as dust by the filter 32, and then the temperature and humidity are adjusted in the air conditioning section 30. The mixed fluid with adjusted temperature and humidity is supplied to the carbon dioxide increasing section 40 as clean air via the pipe L3 and the air supply ports 41 and 42 by operating the blower A1.

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

[0048] The humidity inside the air conditioner 30 is not particularly limited. For example, a humidity range of 5 to 95% RH is preferable, a range of 10 to 80% RH is more preferable, and a range of 20 to 70% RH is even more preferable. When the humidity inside the air conditioner 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 conditioner 30 can be adjusted, for example, by a humidifier, a dehumidifier, or the like.

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

[0050] In this embodiment, the adsorption / desorption unit 50 is located downstream of the carbon dioxide increasing unit 40. Therefore, the air to be treated with an increased carbon dioxide concentration can be supplied to the adsorption / desorption unit 50. As a result, more carbon dioxide can be adsorbed by the adsorbent in the adsorption cylinders 51 and 52. In addition, conventionally, the post-activity air (air to be treated) that was simply discharged is not exhausted outdoors, and the carbon dioxide emission amount can be reduced.

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

[0052] The recovered carbon dioxide is stored in a cylinder or the like and can be effectively used as a carbon source (carbon recycling). Thus, in the recovery step, carbon dioxide with a higher concentration can be recovered.

[0053] The concentration of the recovered carbon dioxide may be, for example, 1000 ppm or more, preferably 1000 - 750000 ppm, 1000 - 500000 ppm, 1000 - 250000 ppm, 1000 - 100000 ppm, more preferably 1000 - 10000 ppm, even more preferably 2000 - 10000 ppm, and particularly preferably 2000 - 5000 ppm. When the concentration of the recovered carbon dioxide is at least the above lower limit, more carbon dioxide can be effectively utilized. When the concentration of the recovered carbon dioxide is at most the above upper limit, management becomes easier. The concentration of the recovered carbon dioxide can be adjusted by the type and amount of the adsorbent, the pressure inside the adsorption / desorption unit 50, the temperature inside the adsorption / desorption unit 50, the time in the desorption step, and combinations thereof.

[0054] In this embodiment, the desorption step by pressure difference has been described, but the present invention is not limited to the above-described embodiment. The desorption step may be desorption based on the principle of temperature swing adsorption (TSA) using a temperature difference, or desorption by both a pressure difference and a temperature difference. By performing desorption by both a pressure difference and a temperature difference, carbon dioxide can be desorbed more efficiently. As the temperature difference, for example, 10 - 200°C is preferable, 20 - 180°C is more preferable, and 30 - 160°C is even more preferable. When the temperature difference is at least the above lower limit, more carbon dioxide can be desorbed. When the temperature difference is at most the above 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 includes a plurality of the above-described air conditioning systems on different floors. In the building air conditioning system, there may be one or more air conditioning systems of the present invention on one floor. For example, by providing an air conditioning system on two or more floors, the amount of carbon dioxide recovered can be increased. In this case, the carbon dioxide discharged from the air conditioning systems on different floors may be stored floor by floor, or may 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] An example of the building air conditioning system of the present invention will be described. The building air conditioning system 200 in FIG. 2 includes a plurality of air conditioning units 210, a carbon dioxide discharge section L20, a pipe L21, and a recovery section 60. The air conditioning units 210 are provided on each above-ground floor A of the building 201. The pipe L21 extends vertically within the building 201 and reaches from the top above-ground floor to the basement floor B. The pipe 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 above-ground floor A are connected to the pipe L21 via the carbon dioxide discharge section L20. Examples of the carbon dioxide discharge section L20 include pipes similar to the carbon dioxide discharge sections L9 and L10. Examples of the pipe L21 include ducts similar to the pipe L14.

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

[0058] In the building air conditioning system 200 of the present embodiment, the carbon dioxide discharged from the air conditioning units 210 on each above-ground 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 recovering carbon dioxide on each floor and aggregating it, more carbon dioxide can be recovered.

[0059] As described above, according to the air conditioning system of the present embodiment, carbon dioxide can be removed from outside air and indoor air. Therefore, treated air with a reduced carbon dioxide concentration can be supplied to the living 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, since the treated air can be circulated and used, it is not necessary to rely on outside air for the air supplied to the living room. Therefore, the outside air load, which is said to account for 40% of the air conditioning load, can be reduced. According to the air conditioning system of the present embodiment, since the air conditioning load can be reduced, the air conditioning cost can be reduced and the energy consumed for air conditioning can be reduced. This leads to a reduction in the amount of carbon dioxide emissions from power plants. According to the air conditioning system of the present embodiment, since carbon dioxide in outside air can be directly recovered, if it is widely used, it will lead to a reduction in carbon dioxide throughout the world. In addition, since carbon dioxide in outside air can be directly recovered, a larger and more stable amount of carbon dioxide can be recovered compared to the conventional technology that absorbs carbon dioxide only from indoor exhaust. The carbon dioxide adsorbed and recovered by the air conditioning system, building air conditioning system or carbon dioxide recovery method of the present embodiment can stably supply the amount required for industrial use. Therefore, the recovered carbon dioxide is suitable as a material for synthesizing C1 compounds such as carbon monoxide, methane, methanol and formic acid, C2 compounds such as ethane, ethylene and ethanol, or olefin compounds such as propylene and butene by chemical engineering processes such as artificial photosynthesis. Thus, the technology of the present invention is beneficial to the global environment.

[0060] As described above, the preferred embodiments of the present invention have been described in detail. However, the present invention is not limited to such specific embodiments, and various modifications are possible within the scope of the gist of the present invention described in the claims.

[0061] In the above-described embodiment, two adsorption / desorption cylinders are provided, but the present invention is not limited thereto. For example, the number of adsorption / desorption cylinders may be one or three or more. When the number of adsorption / desorption cylinders is one, carbon dioxide can be adsorbed and desorbed using a single adsorption / desorption cylinder. When the number of adsorption / desorption cylinders is three or more, carbon dioxide can be adsorbed using any one of the adsorption / desorption cylinders and desorbed using any other one of the adsorption / desorption cylinders. After switching between carbon dioxide adsorption and desorption, carbon dioxide can be desorbed using any one of the adsorption / desorption cylinders and adsorbed using any other one of the adsorption / desorption cylinders. The number of any one of the adsorption / desorption cylinders and the number of any other one of the adsorption / desorption cylinders are not particularly limited, but considering the balance between carbon dioxide adsorption and desorption, it is preferable that the number of any one of the adsorption / desorption cylinders and the number of any other one of the adsorption / desorption cylinders are equal. The number of adsorption / desorption cylinders is preferably two because it can make the air conditioning system more compact.

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

Explanation of Reference Numerals

[0063] 1…Air conditioning system, 10…Air supply unit, 12…Outdoor air intake, A1, A2…Blowers, 20…Mixing unit, 30…Air conditioning unit, 32…Filter, 40…Carbon dioxide increasing unit, 41, 42…Air supply ports, 43…Exhaust port, 50…Adsorption / desorption unit, 51, 52…Adsorption / desorption cylinders, 60…Recovery unit, D1, D3, D4, D5, D6, D7, D8…Dampers, L7, L8…Air discharge section, L9, L10, L20…Carbon dioxide discharge section, L0, L1, L2, L3, L4, L5, L6, L11, L12, L13, L14, L21…Pipes, P1…Pump, 101, 102, 103, 104, 105…Branches, 200…Building air conditioning system, 201…Building, 210…Air conditioning unit, 212…Vacuum pump

Claims

【Claim 1】 An air conditioning system that recovers carbon dioxide and reuses the recovered carbon dioxide, comprising: a carbon dioxide increasing portion where the concentration of carbon dioxide increases, an air supply portion that supplies outside air to the carbon dioxide increasing portion, a mixing portion, an air conditioning portion, an adsorption / desorption portion, and a recovery portion; the mixing portion is located downstream of the adsorption / desorption portion; the adsorption / desorption portion includes a first adsorption / desorption cylinder that adsorbs or desorbs carbon dioxide, a second adsorption / desorption cylinder that adsorbs or desorbs carbon dioxide, and an adsorbent carried on the first adsorption / desorption cylinder and the second adsorption / desorption cylinder and having carbon dioxide adsorption ability; while carbon dioxide is being adsorbed in the first adsorption / desorption cylinder, carbon dioxide is being desorbed in the second adsorption / desorption cylinder; while carbon dioxide is being adsorbed in the second adsorption / desorption cylinder, carbon dioxide is being desorbed in the first adsorption / desorption cylinder; processing target air containing carbon dioxide is supplied from the carbon dioxide increasing portion to the adsorption / desorption portion, and the processing target air is brought into contact with the adsorbent, so that part or all of the carbon dioxide in the processing target air is adsorbed by the adsorbent to obtain processed air, the processed air is discharged from the adsorption / desorption portion, and the processed air is supplied to the mixing portion; the first adsorption / desorption cylinder and the second adsorption / desorption cylinder desorb the carbon dioxide adsorbed by the adsorbent by reducing the internal pressure or reducing the partial pressure of carbon dioxide, the desorbed carbon dioxide is discharged from the adsorption / desorption portion, the carbon dioxide is supplied to the recovery portion, the recovery portion recovers the carbon dioxide, and the recovered carbon dioxide is used as a carbon source; the processed air discharged from the adsorption / desorption portion and the outside air supplied from the air supply portion are mixed in the mixing portion to form a mixed fluid; an air conditioning system that cleans the mixed fluid supplied from the mixing portion in the air conditioning portion, adjusts the temperature, and then supplies the mixed fluid from the air conditioning portion to the carbon dioxide increasing portion.

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