Vehicle air conditioning method and vehicle air conditioning system

Abstract

To provide an air conditioning method for a vehicle, which is able to efficiently reduce carbon dioxide from air in a vehicle cabin containing not only carbon dioxide but also H20 at high concentrations, by using a gas separation film, and to provide a system therefor.SOLUTION: An air conditioning system 1 for a vehicle, according to the present invention, comprises: a film module 5 that has a gas separation film having a CO2 / N2 selectivity greater than 1, wherein air in a vehicle cabin is supplied to the gas separation film as a supply gas, and a gas passed through the gas separation film is discharged by a sweep gas; and a dehumidifier 3 that performs one or both of dehumidification of the supply gas and humidification of the sweep gas so that a partial pressure difference between a partial pressure of H2O of the supply gas and a partial pressure of H2O of the sweep gas is smaller than a partial pressure difference between a partial pressure of CO2 of the supply gas and a partial pressure of CO2 of the sweep gas.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a vehicle air conditioning method and a vehicle air conditioning system in which an air flow is extracted from a vehicle cabin, supplied to a membrane module, and carbon dioxide is reduced in the membrane module before the air flow is returned to the vehicle cabin. [Background technology]

[0002] In recent years, with the spread of electric vehicles, the importance of reducing the energy consumption required for heating and cooling the vehicle cabin has increased. In particular, in winter, heating is performed using exhaust heat from vehicles equipped with conventional internal combustion engines, so the additional energy required for heating is hardly an issue. Therefore, in the past, the airtightness of the vehicle cabin was generally poor, and even in the air conditioning system's internal air circulation mode, ventilation efficiency with outside air was high.

[0003] However, because electric vehicles generate almost no exhaust heat, they consume additional electricity for both cooling and heating. As a result, the driving range is reduced when the air conditioning system is in use. Therefore, in order to improve the air conditioning efficiency of electric vehicles and prevent the reduction in driving range, it was necessary to improve the airtightness of the vehicle interior and increase the efficiency of air circulation within the vehicle.

[0004] However, increasing the airtightness of the interior of a car can lead to problems such as increased humidity, which can cause windows to fog up, and increased carbon dioxide levels, which can cause drowsiness and reduce concentration.

[0005] Therefore, in electric vehicles, there is a need to dehumidify the interior of the vehicle to reduce carbon dioxide, and as a solution to this problem, Patent Document 1 proposes a method of reducing carbon dioxide using a gas separation membrane. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Special Publication No. 2006-512946 Summary of the Invention [Problem to be solved by the invention]

[0007] However, gas separation membranes generally have a higher H 2 O This tendency is particularly pronounced in polymer gas separation membranes, but the air inside a car contains not only carbon dioxide but also H 2 O Therefore, when carbon dioxide is removed from the air inside a vehicle using a gas separation membrane, H 2 O However, there was a problem in that carbon dioxide could not be removed efficiently.

[0008] Therefore, the present invention has been made in view of the above problems, and is directed to a method for treating not only carbon dioxide but also H 2 O The present invention aims to provide a vehicle air conditioning method and system that can efficiently remove carbon dioxide from the air in a vehicle cabin, which contains carbon dioxide at extremely high concentrations, using a gas separation membrane. [Means for solving the problem]

[0009] In a vehicle air conditioning method according to one aspect of the present invention, a membrane module includes a gas separation membrane having a CO2 / N2 selectivity greater than 1, and the air in the vehicle cabin is supplied to the gas separation membrane as a supply gas, and the gas that has permeated the gas separation membrane is discharged as a sweep gas. The supply gas is dehumidified and the sweep gas is humidified so that the partial pressure difference between the partial pressure of HO in the supply gas and the partial pressure of HO in the sweep gas is smaller than the partial pressure difference between the partial pressure of CO2 in the supply gas and the partial pressure of CO2 in the sweep gas. H 2 O The sweep gas is humidified using [Effects of the Invention]

[0010] According to the present invention, it is possible to efficiently remove carbon dioxide using a gas separation membrane from the air inside a vehicle cabin that contains not only carbon dioxide but also H2O at high concentrations. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram showing the configuration of a vehicle air conditioning system according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing the configuration of a vehicle air conditioning system according to the first embodiment of the present invention. [Figure 3] FIG. 3 is a diagram showing the results of membrane separation evaluation using the membrane module of the vehicle air conditioning system according to the first embodiment of the present invention. [Figure 4] FIG. 4 is a diagram showing the relationship between the partial pressure difference of H 2 O and the partial pressure difference of CO2 in the vehicle air conditioning system according to the first embodiment of the present invention. [Figure 5] FIG. 5 is a flowchart showing the procedure of the air conditioning process performed by the vehicle air conditioning system according to the first embodiment of the present invention. [Figure 6] FIG. 6 is a diagram showing the configuration of a vehicle air conditioning system according to a first modification of the first embodiment of the present invention. [Figure 7] FIG. 7 is a diagram showing the configuration of a vehicle air conditioning system according to a second modification of the first embodiment of the present invention. [Figure 8] FIG. 8 is a diagram showing the configuration of a vehicle air conditioning system according to a second modification of the first embodiment of the present invention. [Figure 9] FIG. 9 is a diagram showing the configuration of a vehicle air conditioning system according to a third modification of the first embodiment of the present invention. [Figure 10] FIG. 10 is a diagram showing the configuration of a vehicle air conditioning system according to a second embodiment of the present invention. [Figure 11] FIG. 11 is a diagram showing the configuration of a vehicle air conditioning system according to a modified example of the second embodiment of the present invention. [Figure 12] FIG. 12 is a diagram showing the configuration of a vehicle air conditioning system according to a modified example of the second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the description of the drawings, the same parts are given the same reference numerals and detailed description will be omitted.

[0013] [First embodiment] [Configuration of vehicle air conditioning system] FIG. 1 is a diagram showing the configuration of a vehicle air conditioning system according to this embodiment. As shown in FIG. 1, the vehicle air conditioning system 1 according to this embodiment includes a dehumidifier 3 and a membrane module 5, and is installed in a vehicle such as an electric vehicle. The vehicle air conditioning system 1 extracts air from a vehicle interior (cabin) 7 and purifies it with carbon dioxide and H 2 O The air conditioning is operated in an inside air circulation mode in which the temperature is reduced and the air is returned to the passenger compartment 7.

[0014] In the internal air circulation mode, the airflow extracted from the vehicle compartment 7 is circulated through the circulation path 9, and is first dehumidified by the dehumidifier 3. The dehumidified airflow is then sent as supply gas to the membrane module 5, where carbon dioxide is reduced. The airflow with reduced carbon dioxide is then returned to the vehicle compartment 7 through the circulation path 9. Meanwhile, the exhaust path 11 introduces a mixture of the air in the vehicle compartment 7 and outside air, or only outside air, and the air is dehumidified by the dehumidifier 3. H 2 O After being humidified using the above-mentioned method, the gas is supplied as a sweep gas to the membrane module 5. Thereafter, the gas discharged from the membrane module 5 is released into the outside air.

[0015] The dehumidifier 3 is an example of a dehumidification device that dehumidifies the supply gas of the membrane module 5 and / or humidifies the sweep gas. In this embodiment, the dehumidifier 3 humidifies the air flow extracted from the casing 7. H 2 O Since the dehumidifier 3 removes the humidified gas, the gas supplied to the membrane module 5 is dehumidified. H 2 OSince the gas flowing through the exhaust line 11 is humidified using the above, the sweep gas of the membrane module 5 is also humidified. In other words, both the supply gas and the sweep gas are dehumidified.

[0016] At this time, the dehumidifier 3 dehumidifies the supply gas and humidifies the sweep gas so that the partial pressure difference between the partial pressure of H2O in the supply gas and the partial pressure of H2O in the sweep gas is smaller than the partial pressure difference between the partial pressure of CO2 in the supply gas and the partial pressure of CO2 in the sweep gas.

[0017] An air conditioning system installed in a vehicle may be used as the dehumidifier 3. As shown in Fig. 2, an H2O separation membrane 13 may be used instead of the dehumidifier 3 to dehumidify the airflow extracted from the vehicle interior 7 and humidify the gas flowing through the exhaust path 11.

[0018] The membrane module 5 is equipped with a gas separation membrane (CO2 separation membrane) having a CO2 / N2 selectivity greater than 1, and removes CO2 from the air flow extracted from the casing 7. Air from the casing 7 is supplied to the gas separation membrane as a feed gas, and the gas that permeates the gas separation membrane is discharged as a sweep gas. In this embodiment, as shown in FIG. 1, the feed gas is dehumidified by the dehumidifier 3, and the sweep gas is humidified by the dehumidifier 3. That is, both the feed gas and the sweep gas are dehumidified; however, it is also possible to perform only one of the two. For example, if outside air is used as the sweep gas for the membrane module 5, the sweep gas is not humidified, and only the feed gas is dehumidified. A case in which only the sweep gas is humidified will be described in Modification 2.

[0019] In this way, by supplying the dehumidified feed gas and the humidified sweep gas to the membrane module 5, the feed gas in the membrane module 5 can be H 2 O The partial pressure of the sweep gas H 2 O The partial pressure difference between the partial pressure of the

[0020] For example, in Figure 1, the air inside the vehicle is H 2 O However, since it is dehumidified by dehumidifier 3, the concentration of H 2 O The partial pressure of decreases from a high value. On the other hand, the sweep gas is made of outside air or mixed gas introduced and humidified by the dehumidifier 3. H 2 O As a result, the partial pressure of the supply gas increases from a low value. H 2 O The partial pressure of the sweep gas H 2 O The partial pressures of are close to each other, H 2 O The partial pressure difference can be reduced.

[0021] And it got smaller H 2 O If the partial pressure difference between the supply gas and the sweep gas is smaller than the partial pressure difference between the supply gas and the sweep gas, H 2 O Using a gas separation membrane, CO2 can be efficiently reduced from the air inside a vehicle, where CO2 concentrations are high.

[0022] Specifically, gas separation membranes generally have a higher H 2 O The air inside a car is not only contaminated by CO2 but also by the breathing of passengers. H 2 O Therefore, if we try to reduce CO2 from the air inside a vehicle using a gas separation membrane, H 2 O is removed, making it impossible to reduce CO2 efficiently.

[0023] However, the supply gas H 2 O The partial pressure of the sweep gas H 2 O If the partial pressure difference between the partial pressure of CO2 in the supply gas and the partial pressure of CO2 in the sweep gas is smaller than the partial pressure difference between the partial pressure of CO2 in the supply gas and the partial pressure of CO2 in the sweep gas, H 2 Ois no longer preferentially removed, allowing for efficient CO2 reduction.

[0024] Here, the results of CO2 removal by the vehicle air conditioning system 1 according to this embodiment will be described with reference to Fig. 3. Fig. 3 shows the results of membrane separation evaluation using the membrane module 5 for a mixed gas of 21% O2-5000 ppm CO2-bal.N2 at 17°C. The flow rate of the supply gas was 0.05 m / sec, and the sweep gas was also supplied at a similar flow rate. A hollow fiber polyimide gas separation membrane module was used as the membrane module 5.

[0025] As shown in Figure 3, in Experimental Example 1, the relative humidity of the supply gas and the sweep gas were adjusted to 100% and 80%, respectively. H 2 O The partial pressure difference between the supply gas and the sweep gas is 0.37 kPa. In Experimental Example 2, the relative humidity of both the supply gas and the sweep gas is adjusted to 15%. H 2 O The partial pressure difference is 0 kPa. Furthermore, as a comparative example, the relative humidity of the supply gas and the sweep gas is adjusted to 100% and 15%, respectively. H 2 O The partial pressure difference of CO2 was 0.5 kPa in both cases.

[0026] When comparing the CO2 recovery rates of Experimental Examples 1 and 2 with those of the Comparative Example, as shown in Figure 3, H 2 O In Experiment 2, where the partial pressure difference was the smallest, the CO2 recovery rate was 65%, and the most CO2 was removed. H 2 O In Experimental Example 1, where the partial pressure difference between the CO2 and the CO2 was small, the CO2 recovery rate was 58%, which was a good recovery rate. H 2 O In the comparative example in which the partial pressure difference of CO2 was 1.61 kPa, which was larger than the partial pressure difference of CO2, the recovery rate of CO2 was 47%, which was not a good result as the recovery rate was less than 50%.

[0027] As a result, as shown in FIG. 4, H 2 O In Experimental Examples 1 and 2 located in the region above the straight line A where the relationship of the partial pressure difference <CO2 partial pressure difference holds, it was found that a good CO2 recovery rate could be achieved. On the other hand, in the Comparative Example located in the region below the straight line A, a good CO2 recovery rate could not be obtained. Also, since the CO2 recovery rate is higher in Experimental Example 2 than in Experimental Example 1, H 2 O it was found that the smaller the partial pressure difference of <CO2, the better the CO2 recovery rate.

[0028] Thus, H 2 O by making the partial pressure difference of <CO2 smaller than the partial pressure difference of CO2, not only carbon dioxide but also H 2 O can be efficiently reduced from the air in the passenger compartment containing <CO2 at a high concentration. Therefore, in the vehicle air conditioning method according to the present embodiment, by performing either or both of dehumidification of the supply gas and humidification of the sweep gas, H 2 O the partial pressure difference of <CO2 is made smaller than the partial pressure difference of CO2.

[0029] [Vehicle air conditioning method] FIG. 5 is a flowchart showing the processing procedure of the air conditioning treatment by the vehicle air conditioning system 1 according to the present embodiment. The air conditioning treatment by the vehicle air conditioning system 1 according to the present embodiment starts when the air conditioning of the vehicle equipped with the system is turned on by the occupant.

[0030] As shown in FIG. 5, in step S1, the dehumidifier 3 performs either or both of dehumidification of the supply gas and humidification of the sweep gas. At this time, the dehumidifier 3 is preset regarding the method of performing dehumidification of the supply gas and humidification of the sweep gas, and performs dehumidification so that the partial pressure difference of H2O in the membrane module 5 becomes smaller than the partial pressure difference of CO2. Also, by controlling the air conditioning system by a controller not shown, dehumidification of the supply gas and humidification of the sweep gas may be performed.

[0031] As shown in FIG. 2, when an H2O separation membrane 13 is installed instead of the dehumidifier 3, the H2O separation membrane 13 is installed so that the partial pressure difference of H2O in the membrane module 5 is smaller than the partial pressure difference of CO2, and is capable of dehumidifying the supply gas and humidifying the sweep gas.

[0032] Next, in step S3, carbon dioxide is removed by the membrane module 5. The membrane module 5 is equipped with a CO2 separation membrane with a CO2 / N2 selectivity greater than 1, and therefore removes carbon dioxide from the supply gas sent from the dehumidifier 3, thereby reducing the carbon dioxide in the air flowing through the circulation path 9. Then, while the air conditioning of the vehicle equipped with the system is turned on, the air conditioning process continues, and when the air conditioning is turned off by the occupant, the air conditioning process by the vehicle air conditioning system 1 according to this embodiment ends.

[0033] [Variation 1] Next, modified examples of the vehicle air conditioning system according to this embodiment will be described with reference to the drawings. Fig. 6 is a diagram showing the configuration of a vehicle air conditioning system according to Modification 1. As shown in Fig. 6, the vehicle air conditioning system 1 according to Modification 1 differs from the system shown in Fig. 1 in that the flow direction of the sweep gas supplied to the membrane module 5 is opposite to the flow direction of the supply gas flowing through the circulation path 9. The supply gas and sweep gas supplied to the membrane module 5 may flow in the same direction as shown in Fig. 1, or may flow in opposite directions as shown in Fig. 6.

[0034] [Variation 2] Fig. 7 is a diagram showing the configuration of a vehicle air conditioning system according to Modification 2. As shown in Fig. 7, the vehicle air conditioning system 1 according to Modification 2 differs from the system shown in Fig. 1 in that the positions of the dehumidifier 3 and the membrane module 5 are interchanged.

[0035] That is, the air flow extracted from the casing 7 is first sent to the membrane module 5, where carbon dioxide is reduced, and then dehumidified by the dehumidifier 3. The dehumidified air flow is then returned to the casing 7 via the circulation path 9. Meanwhile, a mixed gas of the air in the casing 7 and outside air, or only outside air, is introduced into the exhaust path 11, where it is humidified by the dehumidifier 3 and then supplied as a sweep gas for the membrane module 5. The gas discharged from the membrane module 5 is then released into the outside air. Therefore, in the membrane module 5, the sweep gas and the supply gas flow in opposite directions, and the sweep gas is humidified, but the supply gas is the air from the casing 7 that is supplied as is.

[0036] In this way, by switching the positions of the dehumidifier 3 and the membrane module 5, in the second modification, only the sweep gas is humidified, and the supply gas is not dehumidified. If the sweep gas is humidified, the dehumidification of the membrane module 5 can be achieved even if the supply gas is not dehumidified. H 2 O It is possible to make the partial pressure difference between the two smaller than the partial pressure difference between the two, and carbon dioxide can be efficiently reduced from the air in the vehicle cabin using a gas separation membrane. Also, as shown in Figure 8, the flow direction of the sweep gas supplied to the membrane module 5 may be made the same as the flow direction of the supply gas.

[0037] [Variation 3] Fig. 9 is a diagram showing the configuration of a vehicle air conditioning system according to Modification 3. As shown in Fig. 9, in the vehicle air conditioning system 1 according to Modification 3, a compressor 20 is provided at a position where airflow is extracted from the vehicle compartment 7 to the circulation path 9. This makes it possible to pressurize the airflow flowing through the circulation path 9, thereby facilitating the removal of CO2 in the membrane module 5. Alternatively, a blower 20 may be provided instead of the compressor 20.

[0038] [Effects of the first embodiment] As described above in detail, in the vehicle air conditioning method according to this embodiment, the membrane module 5 includes a gas separation membrane with a CO2 / N2 selectivity greater than 1. The gas separation membrane is supplied with air from the vehicle cabin as a feed gas, and the gas that permeates the gas separation membrane is discharged as a sweep gas. The feed gas is dehumidified, the sweep gas is humidified, or both, so that the partial pressure difference between the HO partial pressures of the feed gas and the HO partial pressures of the sweep gas is smaller than the partial pressure difference between the CO2 partial pressures of the feed gas and the CO2 partial pressures of the sweep gas. This allows the gas separation membrane to efficiently remove carbon dioxide from the air from the vehicle cabin, which contains high concentrations of not only carbon dioxide but also HO.

[0039] Furthermore, in the vehicle air conditioning method according to this embodiment, the supply gas is dehumidified using the H2O separation membrane 13, which makes it possible to reduce the weight compared to when an adsorbent is used, and to reduce the temperature change compared to when dehumidifying by cooling.

[0040] Furthermore, in the vehicle air conditioning method according to this embodiment, the supply gas is dehumidified by the air conditioning system installed in the vehicle. This allows both temperature regulation and dehumidification processes to be performed by a single means during cooling, making it possible to achieve a compact, lightweight, and energy-efficient system.

[0041] Furthermore, in the vehicle air conditioning method according to this embodiment, a blower or compressor 20 is provided in the path through which air flows out of the vehicle compartment. This allows the air flowing through the circulation path 9 to be pressurized, thereby facilitating the removal of CO2 in the membrane module 5.

[0042] [Second embodiment] A second embodiment of the present invention will be described below with reference to the drawings. In the description of the drawings, the same parts are given the same reference numerals and detailed description will be omitted.

[0043] [Configuration of vehicle air conditioning system] Fig. 10 is a diagram showing the configuration of a vehicle air conditioning system according to this embodiment. As shown in Fig. 10, in a vehicle air conditioning system 1 according to this embodiment, an oxygen-enriched gas is generated from outside air by an oxygen separation membrane 22. The generated oxygen-enriched gas is mixed with an air flow in which carbon dioxide has been reduced by a membrane module 5, and the temperature of the mixed gas is adjusted by a temperature adjuster 24 before being returned to the vehicle interior 7, which is different from the first embodiment.

[0044] The oxygen separation membrane 22 can extract high-concentration oxygen from the outside air, generating an oxygen-enriched gas and mixing it with the air flow in the circulation path 9. The temperature regulator 24 is an air conditioning system or heater installed in the vehicle, and changes the temperature of the air flowing through the circulation path 9 using a refrigerant.

[0045] In an electric vehicle, when outside air is introduced to replenish the oxygen consumed inside the vehicle cabin, the air is at a different temperature from the inside of the vehicle, which means that energy is consumed to regulate the temperature. To reduce this energy consumption, it is important to reduce the amount of air introduced into the vehicle cabin as much as possible and to reduce the amount of air circulated to the temperature regulator 24.

[0046] Therefore, in the vehicle air conditioning system 1 according to this embodiment, only the amount of outside air that is exhausted from the vehicle interior is taken in, adjusted to a predetermined temperature by the temperature regulator 24, and then circulated into the vehicle interior. This minimizes the amount of air introduced into the vehicle interior, thereby minimizing temperature changes within the vehicle interior and preventing excessive circulation of air within the vehicle interior for temperature adjustment.

[0047] Furthermore, to compensate for the amount of exhausted air and supply oxygen, it is possible to simply take in outside air, but if an oxygen-enriched gas is supplied, a predetermined oxygen concentration can be maintained with a smaller amount of air, thereby reducing the energy required for temperature control. Furthermore, if an oxygen separation membrane 22 is used to generate the oxygen-enriched gas, it is possible to make the system smaller and lighter than when other methods are used, making it more suitable for an in-vehicle system.

[0048] [Variations] Next, a modified example of the vehicle air conditioning system according to this embodiment will be described with reference to the drawings. Fig. 11 is a diagram showing the configuration of a vehicle air conditioning system according to the modified example. As shown in Fig. 11, the vehicle air conditioning system 1 according to the modified example differs from the system shown in Fig. 10 in that a compressor 26 blows outside air to the oxygen separation membrane 22. Furthermore, a blower 26 may be provided instead of the compressor 26.

[0049] 11, an HO separation membrane 13 is provided instead of the dehumidifier 3, and the positions of the HO separation membrane 13 and the membrane module 5 are interchanged. The nitrogen-enriched gas discharged when the oxygen-enriched gas is produced by the oxygen separation membrane 22 is humidified by the HO separation membrane 13 and then supplied to the membrane module 5 as a sweep gas.

[0050] In this way, by blowing outside air against the oxygen separation membrane 22 using the compressor 26 or the blower 26, it becomes possible to introduce the oxygen-enriched gas into the circulation path 9 at a high speed and efficiently. Furthermore, by humidifying the nitrogen-enriched gas obtained when generating the oxygen-enriched gas with the HO separation membrane 13 and then using it as a sweep gas for the membrane module 5, it is possible to increase the flow rate of the sweep gas and the rate at which CO2 is removed.

[0051] Furthermore, the flow rate of the sweep gas in each module can be changed by changing the cross-sectional area of ​​the exhaust path 11 through which the sweep gas flows in the membrane module 5 and the HO separation membrane 13. This allows the flow rate of the sweep gas to be set to a flow rate suitable for removing HO and CO.

[0052] 12, instead of the compressor 26, a pump 28 may be provided in the path for discharging the sweep gas from the membrane module 5. This allows the pressure to be reduced on the side of the membrane module 5 that has permeated the gas separation membrane, thereby increasing the partial pressure difference between the CO2 partial pressure in the supply gas and the CO2 partial pressure in the sweep gas, and thereby increasing the CO2 removal rate.

[0053] [Effects of the second embodiment] As described above in detail, in the vehicle air conditioning method according to this embodiment, oxygen-enriched gas is generated from outside air, the generated oxygen-enriched gas is mixed with the air flow after carbon dioxide reduction by the membrane module 5, and the temperature is adjusted before being returned to the vehicle cabin. This minimizes temperature changes in the vehicle cabin and prevents excessive circulation of air in the vehicle cabin for temperature adjustment. Furthermore, supplying oxygen-enriched gas allows a predetermined oxygen concentration to be maintained with a smaller amount of air, thereby reducing the energy required for temperature adjustment.

[0054] Furthermore, in the vehicle air conditioning method according to this embodiment, the oxygen-enriched gas is generated by the oxygen separation membrane 22, which allows for a reduction in size and weight, making it possible to realize a suitable vehicle-mounted system.

[0055] Furthermore, in the vehicle air conditioning method according to this embodiment, an oxygen-enriched gas is generated by blowing outside air through the oxygen separation membrane 22 by the compressor 26. This allows the generated oxygen-enriched gas to be introduced into the circulation path 9 efficiently and at a high speed.

[0056] Furthermore, in the vehicle air conditioning method according to this embodiment, a pump 28 is provided in the path for discharging the sweep gas from the membrane module 5, and the gas that has permeated the gas separation membrane of the membrane module 5 is depressurized. This allows the membrane module 5 to increase the partial pressure difference between the CO2 partial pressure of the supply gas and the CO2 partial pressure of the sweep gas, thereby increasing the CO2 removal rate.

[0057] Furthermore, in the vehicle air conditioning method according to this embodiment, the nitrogen-enriched gas discharged when the oxygen-enriched gas is produced by the oxygen separation membrane 22 is supplied as a sweep gas to the membrane module 5. This allows the nitrogen-enriched gas accelerated by the air blown by the compressor 26 or the suction of the pump 28 to be used as the sweep gas, thereby increasing the flow rate of the sweep gas and the rate at which CO2 is removed.

[0058] The above-described embodiment is merely an example of the present invention, and therefore the present invention is not limited to the above-described embodiment, and various modifications can be made to the design and other aspects of the present invention without departing from the technical concept of the present invention. [Explanation of symbols]

[0059] 1. Vehicle air conditioning system 3 Dehumidifier 5. Membrane module 7 Cabin 9 Circulation Route 11 Exhaust route 13 H2O separation membrane 20, 26 Compressor or blower 22 Oxygen separation membrane 24 Temperature controller 28 Pump

Claims

1. A vehicle air conditioning method comprising: extracting an air flow from a vehicle cabin, supplying the air flow to a membrane module, reducing carbon dioxide in the membrane module, and then returning the air flow to the vehicle cabin, the method comprising: The membrane module ２ / N ２ a gas separation membrane having a selectivity of greater than 1, wherein the air in the vehicle cabin is supplied to the gas separation membrane as a feed gas, and the gas that has permeated the gas separation membrane is discharged as a sweep gas; H of the supply gas ２ The partial pressure of O and the H of the sweep gas ２ The partial pressure difference between the supply gas and the supply gas ２ and the partial pressure of CO in the sweep gas ２ dehumidifying the supply gas and humidifying the sweep gas so that the partial pressure difference between the supply gas and the sweep gas is smaller than the partial pressure difference between the supply gas and the sweep gas; The H 2 O obtained by dehumidifying the supply gas is used to humidify the sweep gas. A vehicle air conditioning method comprising:

2. 2. The vehicle air conditioning method according to claim 1, further comprising: generating an oxygen-enriched gas from outside air; mixing the generated oxygen-enriched gas with the air flow from which carbon dioxide has been reduced by the membrane module; and adjusting the temperature of the mixed gas before returning it to the vehicle interior.

3. 3. The vehicle air conditioning method according to claim 2, wherein the oxygen-enriched gas is produced by an oxygen separation membrane.

4. 4. The vehicle air conditioning method according to claim 3, wherein the oxygen-enriched gas is generated by blowing outside air through the oxygen separation membrane using a compressor or a blower.

5. 4. The vehicle air conditioning method according to claim 3, further comprising providing a pump in a path for discharging the sweep gas from the membrane module, and reducing the pressure of the gas that has permeated the gas separation membrane.

6. 6. The vehicle air conditioning method according to claim 4, wherein nitrogen-enriched gas discharged when the oxygen-enriched gas is produced by the oxygen separation membrane is supplied to the membrane module as a sweep gas.

7. 7. The vehicle air conditioning method according to claim 1, wherein the supply gas is dehumidified by a gas separation membrane.

8. 7. The vehicle air conditioning method according to claim 1, wherein the supply gas is dehumidified by an air conditioning system mounted on the vehicle.

9. 9. The vehicle air conditioning method according to claim 1, further comprising providing a blower or a compressor in a path for extracting air from the passenger compartment.

10. A vehicle air conditioning system that extracts air from a vehicle cabin, reduces carbon dioxide in the air, and then returns the air to the vehicle cabin, CO ２ / N ２ a membrane module comprising a gas separation membrane having a selectivity of greater than 1, wherein the air in the vehicle cabin is supplied to the gas separation membrane as a feed gas, and the gas that has permeated the gas separation membrane is discharged as a sweep gas; H of the supply gas ２ The partial pressure of O and the H of the sweep gas ２ The partial pressure difference between the supply gas and the supply gas ２ and the partial pressure of CO in the sweep gas ２ a dehumidifier that dehumidifies the supply gas and humidifies the sweep gas so that the partial pressure difference between the supply gas and the sweep gas is smaller than the partial pressure difference between the supply gas and the sweep gas; Equipped with The dehumidifier humidifies the sweep gas using H 2 O obtained by dehumidifying the supply gas. A vehicle air conditioning system comprising:

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