Air composition adjustment system, refrigeration device, and transport container

Abstract

A gas discharge device (300) has an adsorbent that adsorbs carbon dioxide. The gas discharge device (300) performs an adsorption operation and a desorption operation. In the adsorption operation, carbon dioxide contained in the interior air is adsorbed by the adsorbent. In the adsorption operation, the interior air having a temperature equal to or higher than a reference temperature is supplied to the adsorbent. In the desorption operation, carbon dioxide desorbed from the adsorbent is discharged to the outside of a storage space (5).

Description

Air Composition Adjustment System, Refrigeration Apparatus, and Transport Container

[0001] The present disclosure relates to an air composition adjustment system, a refrigeration apparatus, and a transport container.

[0002] Patent Document 1 discloses an indoor air adjustment apparatus that adjusts the composition of indoor air in a transport container. The indoor air adjustment apparatus adjusts the composition of indoor air to maintain the freshness of fruits and vegetables and the like stored in the transport container, which serves as a storage. The indoor air adjustment apparatus generates nitrogen-enriched gas by processing outdoor air, and supplies the generated nitrogen-enriched gas to the indoor space. The nitrogen-enriched gas is a gas having a higher nitrogen concentration and a lower oxygen concentration than outdoor air. The indoor air adjustment apparatus also performs an operation of supplying outdoor air (atmosphere) directly to the indoor space.

[0003] Japanese Unexamined Patent Application Publication No. 2018-148877

[0004] The respiration rate of fruits, vegetables and the like stored in a storage varies depending on the type and state of the fruits, vegetables and the like. For example, when the respiration rate of fruits, vegetables and the like is high, the amount of carbon dioxide generated by respiration of the fruits, vegetables and the like is also large. Therefore, there has been a risk that the carbon dioxide concentration of indoor air cannot be lowered to a target value by the operation of the indoor air adjustment apparatus.

[0005] An object of the present disclosure is to appropriately adjust the carbon dioxide concentration of indoor air.

[0006] A first aspect of the present disclosure is a gas discharge device (300) that discharges carbon dioxide contained in indoor air inside a storage (2) to the outside of the storage (2), the gas discharge device comprising an adsorbent that adsorbs carbon dioxide, performs an adsorption operation of supplying the indoor air to the adsorbent and causing the adsorbent to adsorb carbon dioxide contained in the indoor air, and a desorption operation of discharging carbon dioxide desorbed from the adsorbent by depressurizing the adsorbent to the outside of the storage (2), wherein in the adsorption operation, a temperature of the indoor air supplied to the adsorbent is equal to or higher than a reference temperature.

[0007] The gas exhaust device (300) of the first embodiment adsorbs carbon dioxide contained in the air inside the storage compartment onto an adsorbent and discharges the carbon dioxide desorbed from the adsorbent to the outside of the storage compartment. Therefore, the carbon dioxide concentration in the air inside the storage compartment can be appropriately adjusted. In this embodiment, the gas exhaust device (300) supplies air inside the storage compartment at a temperature above a standard temperature to the adsorbent during the adsorption operation. Therefore, the temperature of the adsorbent during the adsorption operation is maintained at a certain level or higher, and the adsorbent's capacity is exerted.

[0008] A second aspect of the present disclosure is the first aspect, further comprising a heating unit (350) for heating the internal air supplied to the adsorbent, wherein in the adsorption operation, the internal air heated by the heating unit (350) is supplied to the adsorbent.

[0009] In the second embodiment, the heating unit (350) heats the air supplied to the adsorbent during the adsorption operation.

[0010] A third aspect of this disclosure is, in the second aspect described above, the heating unit (350) is a pressurizing pump (311) that heats the air inside the chamber by compressing it.

[0011] In the third embodiment, the heating unit (350), which is a pressurizing pump (311), heats the air inside the chamber supplied to the adsorbent during the adsorption operation by compressing it.

[0012] A fourth aspect of the present disclosure is, in the third aspect described above, a preparatory operation is performed in which the pressurizing pump (311) discharges the air inside the storage chamber and sends it back into the storage chamber (2) without supplying it to the adsorbent, the preparatory operation is started when the pressurizing pump (311) is started, and the adsorption operation is started after the completion of the preparatory operation.

[0013] In the fourth embodiment, the gas discharge device (300) performs a preparatory operation when the pressurizing pump (311) is started. During the preparatory operation, the air inside the chamber is not supplied to the adsorbent. The gas discharge device (300) starts the adsorption operation after the preparatory operation is completed.

[0014] A fifth aspect of the present disclosure is the fourth aspect, wherein the preparation operation is performed until the temperature of the air inside the chamber discharged by the pressurizing pump (311) is equal to or greater than the reference temperature.

[0015] In the fifth embodiment, the gas discharge device (300) starts the adsorption operation after the temperature of the air inside the chamber discharged by the pressurizing pump (311) during the preparation operation has reached or exceeded the reference temperature. Therefore, during the adsorption operation, air inside the chamber at or above the reference temperature is supplied to the adsorbent.

[0016] A sixth aspect of the present disclosure is, in the second aspect described above, the heating unit (350) is an electric heater (351) that heats the air inside the chamber.

[0017] In the sixth embodiment, the heating unit (350), which is an electric heater (351), heats the air inside the chamber that is supplied to the adsorbent during the adsorption operation.

[0018] A seventh aspect of the present disclosure, in the first, second, or sixth aspect described above, includes a supply unit that, in the adsorption operation, sucks in the air inside the storage and supplies it to the adsorbent, and a discharge unit (312) that, in the desorption operation, sucks in the carbon dioxide desorbed from the adsorbent and discharges it to the outside of the storage unit (2).

[0019] An eighth aspect of the present disclosure, in any one of the third to fifth aspects described above, comprises a supply unit that sucks in the air inside the storage chamber and supplies it to the adsorbent during the adsorption operation, and a discharge unit (312) that sucks in the carbon dioxide desorbed from the adsorbent and discharges it to the outside of the storage chamber (2) during the desorption operation, wherein the pressurizing pump (311) also serves as the supply unit.

[0020] In the seventh and eighth embodiments, the gas exhaust device (300) comprises a supply unit (311) and a discharge unit (312). During the adsorption operation of the gas exhaust device (300), the supply unit (311) draws in air from inside the storage and supplies it to the adsorbent. During the desorption operation of the gas exhaust device (300), the discharge unit (312) draws in carbon dioxide desorbed from the adsorbent and discharges it to the outside of the storage unit (2).

[0021] In the eighth aspect, the pressure pump (311) constituting the heating unit (350) also serves as the supply unit. The pressure pump (311) functions as both the heating unit (350) and the supply unit. During the adsorption operation, the pressure pump (311) heats the inhaled outside air by compressing it and supplies the compressed outside air to the adsorbent.

[0022] A ninth aspect of the present disclosure, in the seventh or eighth aspect, comprises an adsorption cylinder (321, 322) filled with the adsorbent, wherein the discharge unit (312) is a depressurizing pump that sucks carbon dioxide from the adsorption cylinder (321, 322) and depressurizes the adsorption cylinder (321, 322).

[0023] In the ninth embodiment, the gas discharge device (300) includes adsorption cylinders (321, 322). During the attachment and detachment operation of the gas discharge device (300), a depressurizing pump, which is the discharge unit (312), depressurizes the adsorption cylinders (321, 322) by drawing carbon dioxide from them.

[0024] A tenth aspect of this disclosure is that, in any one of the first to ninth aspects, the reference temperature is 40°C.

[0025] In the tenth embodiment, during the adsorption operation of the gas exhaust device (300), air inside the chamber at 40°C or higher is supplied to the adsorbent.

[0026] An eleventh aspect of this disclosure is that, in any one of the first to tenth aspects described above, the adsorbent is a metal-organic structure.

[0027] In the eleventh embodiment, the gas exhaust device (300) includes an adsorbent made of a metal-organic structure.

[0028] A twelfth aspect of the present disclosure is that, in any one of the first to eleventh aspects described above, the adsorbent is installed inside the storage compartment (2).

[0029] In the twelfth embodiment, a gas discharge device (300) is installed inside the storage compartment (2).

[0030] A thirteenth aspect of the present disclosure is an air composition adjustment system (90) for adjusting the composition of the internal air inside a storage compartment (2), comprising a gas discharge device (300) according to any one of the first to twelfth aspects described above, and a gas supply device (100) having a processing unit (95) that processes external air outside the storage compartment (2) to generate a supply gas with a different composition from the external air, and supplying the supply gas generated in the processing unit (95) to the inside of the storage compartment (2).

[0031] In the thirteenth embodiment, the air composition adjustment system (90) comprises a gas discharge device (300) and a gas supply device (100). In this embodiment of the air composition adjustment system (90), the gas supply device (100) supplies supply gas into the storage compartment (2), and the gas discharge device (300) discharges carbon dioxide contained in the air inside the compartment to the outside of the storage compartment (2).

[0032] A fourteenth aspect of this disclosure is a refrigeration device (10) comprising the air composition adjustment system (90) of the thirteenth aspect described above and a refrigerant circuit (11) that performs a refrigeration cycle to adjust the temperature of the air inside the chamber.

[0033] The refrigeration apparatus (10) of the 14th embodiment comprises an air composition adjustment system (90) and a refrigerant circuit (11).

[0034] A fifteenth aspect of the present disclosure is a refrigeration device (10) comprising the air composition adjustment system (90) of the thirteenth aspect, a refrigerant circuit (11) that performs a refrigeration cycle having an internal heat exchanger (15) that exchanges heat between the refrigerant and the internal air, and an internal air passage (29) through which the internal air flows and through which the internal heat exchanger (15) is provided, wherein the gas discharge device (300) of the air composition adjustment system (90) is a refrigeration device (10) installed in a position that is inside the storage compartment (2) and outside the internal air passage (29).

[0035] In the refrigeration system (10) of the 15th embodiment, the air inside the storage compartment flows through an internal air passage (29) and exchanges heat with a refrigerant in an internal heat exchanger (15). This embodiment of the refrigeration system (10) includes an air composition control system (90). Within the internal space of the storage compartment (2), the gas discharge device (300) of the air composition control system (90) is installed outside the internal air passage (29) of the refrigeration system (10).

[0036] A sixteenth aspect of this disclosure is a transport container (1) comprising a refrigeration device (10) according to the fifteenth aspect and a container body constituting the storage compartment (2).

[0037] In the sixteenth embodiment, the transport container (1) comprises a refrigeration unit (10) and a container body (2).

[0038] Figure 1 is a schematic perspective view of a transport refrigeration system according to an embodiment. Figure 2 is a cross-sectional view of a transport container equipped with the transport refrigeration system according to an embodiment. Figure 3 is a piping diagram showing the refrigerant circuit of the transport refrigeration system according to an embodiment. Figure 4 is a block diagram showing the configuration of the transport refrigeration system according to an embodiment. Figure 5 is a piping diagram showing the configuration of the gas supply device according to an embodiment. Figure 6 is a diagram corresponding to Figure 5 showing the gas supply device that performs the first operation of the gas supply operation. Figure 7 is a diagram corresponding to Figure 5 showing the gas supply device that performs the second operation of the gas supply operation. Figure 8 is a diagram corresponding to Figure 5 showing the gas supply device that performs the outside air supply operation. Figure 9 is a piping diagram showing the configuration of the gas discharge device according to an embodiment. Figure 10 is a diagram corresponding to Figure 9 showing the gas discharge device that performs the first operation of the gas discharge operation. Figure 11 is a diagram corresponding to Figure 9 showing the gas discharge device that performs the second operation of the gas discharge operation. Figure 12 is a diagram corresponding to Figure 9 showing the gas discharge device that performs the preparation operation. Figure 13 is a cross-sectional view of a transport container showing the installation location of the gas discharge device in the transport container. Figure 14 is a block diagram showing the configuration of the controller of the air composition adjustment system. Figure 15 is a flow chart showing the operation of the controller in controlling the gas exhaust device. Figure 16 is an adsorption isotherm diagram showing an example of the adsorbent's properties. Figure 17 is a piping diagram showing the configuration of the gas exhaust device in the first modified example of another embodiment.

[0039] Embodiments will be described with reference to the drawings. In the following description, the terms "front", "rear", "upper", "lower", "right", and "left" refer to the directions shown in FIG. 1.

[0040] The present embodiment relates to a shipping container (1). This shipping container (1) is a reefer container capable of temperature control inside the container. This shipping container (1) is configured to handle oxygen (O ２ ) in the air, and is used for transporting perishable products that undergo respiration which takes in oxygen and releases carbon dioxide (CO ２ ). Examples of perishable products include fruits and vegetables (vegetables and fruits) and flowers.

[0041] As shown in FIG. 1 and FIG. 2, the shipping container (1) includes a container body (2) and a transport refrigeration device (10). The transport refrigeration device (10) is attached to the container body (2). The shipping container (1) is used for marine transportation, and is conveyed by ships or the like.

[0042] - Container Body - The container body (2) is a storage that accommodates the aforementioned perishable products.

[0043] The container body (2) is formed into a hollow box shape, and is formed to be horizontally elongated. An opening is formed at one longitudinal end of the container body (2), and the opening of the container body (2) is closed by the transport refrigeration device (10). A storage space (5) for storing cargo that is perishable products is formed inside the container body (2).

[0044] A floor panel (3) for placing cargo is disposed at the bottom of the storage space (5). An underfloor channel (4) for flowing air blown out from the transport refrigeration device (10) is formed between the floor panel (3) and the bottom plate of the container body (2). The underfloor channel (4) is a channel extending along the bottom plate of the container body (2) in the longitudinal direction of the container body (2). One end of the underfloor channel (4) is connected to the air outlet (27) of the transport refrigeration device (10), and the other end communicates with the space above the floor panel (3), that is, the space where cargo is stored.

[0045] -Refrigeration unit for transport- A transport refrigeration unit (10) includes a casing (20), a refrigerant circuit (11) that performs a refrigeration cycle, an outside compartment fan (34), and an inside compartment fan (35).

[0046] <Casing> The casing (20) includes an outer compartment wall (21), an inner compartment wall (22), a back plate (24), and a partition plate (25). As will be described later, this casing (20) is provided with the refrigerant circuit (11), the outside compartment fan (34), and the inside compartment fan (35).

[0047] The outer compartment wall (21) is a plate-shaped member disposed so as to cover the open end of the container body (2). A lower portion of the outer compartment wall (21) bulges toward the inside of the container body (2). The inner compartment wall (22) is a plate-shaped member having a shape along the outer compartment wall (21). The inner compartment wall (22) is disposed so as to cover the inner surface of the outer compartment wall (21) facing the inside of the container body (2). A space between the outer compartment wall (21) and the inner compartment wall (22) is filled with a heat insulating material (23).

[0048] The casing (20) has a shape where a lower portion thereof is recessed toward the inside of the container body (2). The lower portion of the casing (20) forms an outdoor equipment compartment (28) that communicates with the external space of the transport container (1). The outdoor fan (34) is disposed in this outdoor equipment compartment (28).

[0049] The back plate (24) is a substantially rectangular flat plate-shaped member. The back plate (24) is disposed more inward of the container body (2) than the inner compartment wall (22), and forms an indoor air flow path (29) between the back plate and the inner compartment wall (22). An upper end of this indoor air flow path (29) forms a suction port (26) of the casing (20), and a lower end thereof forms an air outlet (27) of the casing (20).

[0050] The partition plate (25) is a plate-shaped member positioned to divide the internal air passage (29) vertically. The partition plate (25) is positioned above the internal air passage (29). This partition plate (25) divides the internal air passage (29) into a primary passage (29a) above the partition plate (25) and a secondary passage (29b) below the partition plate (25). The primary passage (29a) communicates with the storage space (5) via an intake port (26). The secondary passage (29b) communicates with the underfloor passage (4) via an outlet port (27). An internal fan (35) is attached to the partition plate (25). The internal fan (35) is positioned to draw in air from the primary passage (29a) and blow it out into the secondary passage (29b).

[0051] <Refrigerant Circuit> As shown in Figure 3, the refrigerant circuit (11) is a closed circuit formed by connecting the compressor (12), the external heat exchanger (13), the expansion valve (14), and the internal heat exchanger (15) with piping. When the compressor (12) is operated, the refrigerant circulates through the refrigerant circuit (11), and a vapor compression refrigeration cycle is performed. As shown in Figure 2, the external heat exchanger (13) is located in the external equipment room (28), and the internal heat exchanger (15) is located in the internal air passage (29). The compressor (12) is also located in the external equipment room (28).

[0052] - Operation of the transport refrigeration system - The transport refrigeration system (10) performs a cooling operation to cool the air inside the transport container (1).

[0053] During cooling operation, the compressor (12) of the refrigerant circuit (11) operates, and the refrigerant circulates in the refrigerant circuit (11), performing a vapor compression refrigeration cycle. In the refrigerant circuit (11), the refrigerant discharged from the compressor (12) passes sequentially through the external heat exchanger (13), the expansion valve (14), and the internal heat exchanger (15), and is then drawn into the compressor (12) and compressed.

[0054] During cooling operation, both the external fan (34) and the internal fan (35) are activated. When the external fan (34) is activated, outside air from the outside of the transport container (1) is drawn into the external equipment room (28) and passes through the external heat exchanger (13). In the external heat exchanger (13), the refrigerant releases heat to the outside air and condenses. When the internal fan (35) is activated, the internal air from the storage space (5) of the transport container (1) is drawn into the internal air passage (29) and passes through the internal heat exchanger (15). In the internal heat exchanger (15), the refrigerant absorbs heat from the internal air and evaporates.

[0055] Let's explain the airflow inside the storage compartment. The air present in the storage space (5) flows through the intake port (26) into the primary airflow channel (29a) of the storage compartment airflow channel (29), and is blown out into the secondary airflow channel (29b) by the storage compartment fan (35). The air that flows into the secondary airflow channel (29b) is cooled as it passes through the storage compartment heat exchanger (15), and is then blown out from the outlet (27) into the underfloor airflow channel (4), and flows back into the storage space (5) through the underfloor airflow channel (4).

[0056] During cooling operation, the cooling capacity of the transport refrigeration unit (10) is adjusted so that the temperature of the air blown out from the outlet (27) of the transport refrigeration unit (10) falls within the target temperature range. The cooling capacity of the transport refrigeration unit (10) is adjusted by changing the rotational speed of the compressor (12). Increasing the rotational speed of the compressor (12) increases the cooling capacity of the transport refrigeration unit (10), while decreasing the rotational speed of the compressor (12) decreases the cooling capacity of the transport refrigeration unit (10).

[0057] The target temperature range is a temperature range that includes the internal set temperature Ts. In this embodiment, the target temperature range is (Ts - β) or greater and (Ts + β) or less. β is, for example, "1°C". The internal set temperature Ts is the set value of the ambient temperature in the storage space (5). The internal set temperature Ts is set to a temperature suitable for preserving the items stored in the storage space (5). For example, if the items stored in the storage space (5) are mangoes, the internal set temperature Ts is set to 14°C.

[0058] -Air Composition Adjustment System- The transport refrigeration unit (10) is equipped with an air composition adjustment system (90). The air composition adjustment system (90) also includes a gas supply device (100), a gas discharge device (300), and a controller (110).

[0059] The air composition control system (90) is installed in the transport refrigeration unit (10) to perform so-called CA (Controlled Atmosphere) transport. The air composition control system (90) adjusts the air composition in the storage space (5) of the transport container (1).

[0060] The gas supply device (100) generates a supply gas with a different composition from the outside air by processing the outside air, which is the ambient air. The gas supply device (100) supplies the generated supply gas to the storage space (5) of the storage compartment (2).

[0061] The gas exhaust device (300) draws in the air present in the storage space (5) and separates carbon dioxide from the drawn-in air. The gas exhaust device (300) then discharges the carbon dioxide separated from the air outside the transport container (1).

[0062] -Gas supply device- As shown in Figure 5, the gas supply device (100) comprises a filter unit (220), a main unit (200), a gas supply pipe (275), a gas discharge pipe (276), a sensor unit (160), and a ventilation exhaust pipe (150). The gas supply device (100) is a so-called PSA (Pressure Swing Adsorption) type gas separation device.

[0063] The gas supply device (100) generates supply gas by processing the outside air, which is the ambient air. Specifically, the gas supply device (100) separates the outside air into nitrogen-enriched gas, which has a higher nitrogen concentration and a lower oxygen concentration than the outside air, and oxygen-enriched gas, which has a lower nitrogen concentration and a higher oxygen concentration than the outside air. The gas supply device (100) supplies the nitrogen-enriched gas to the storage space (5) as supply gas. The oxygen concentration of the nitrogen-enriched gas is, for example, about 3%.

[0064] <Filter Unit, Outside Air Pipe> The filter unit (220) is a box-shaped component. The filter unit (220) is installed in the outside equipment room (28) of the transport refrigeration unit (10). The filter unit (220) includes an air filter (221). The air filter (221) is a filter for capturing dust, salt, and other particles contained in the outside air. The air filter (221) in this embodiment is a membrane filter that has both breathability and waterproofing properties.

[0065] The filter unit (220) is connected to the main unit (200) via an outside air pipe (241). One end of the outside air pipe (241) is connected to the filter unit (220). The other end of the outside air pipe (241) is connected to an air pump (231), which will be described later. The outside air pipe (241) guides the outside air (atmosphere) that has passed through the air filter (221) to the air pump (231).

[0066] <Main Unit> The main unit (200) is installed in the external equipment room (28) of the transport refrigeration system (10). The main unit (200) comprises an air pump (231), a first suction cylinder (234), a second suction cylinder (235), a first switching valve (232), a second switching valve (233), and a unit case (201) that houses these components. The unit case (201) houses an inlet pipe (242), a suction pipe (243), a first gas pipe (244), and a second gas pipe (245).

[0067] <Air Pump> The air pump (231) comprises a pressurizing pump (231a), a depressurizing pump (231b), and a drive motor (231c). The pressurizing pump (231a) and the depressurizing pump (231b) each draw in and discharge air. The pressurizing pump (231a) and the depressurizing pump (231b) are connected to the drive shaft of a single drive motor (231c). In the air pump (231), both the pressurizing pump (231a) and the depressurizing pump (231b) are driven by a single drive motor (231c).

[0068] The other end of the outside air pipe (241) is connected to the intake port of the pressurizing pump (231a). One end of the inlet pipe (242) is connected to the discharge port of the pressurizing pump (231a). The pressurizing pump (231a) supplies the air to be treated, drawn in from the outside air pipe (241), to the first adsorption cylinder (234) and the second adsorption cylinder (235) through the inlet pipe (242).

[0069] A suction tube (243) is connected to the inlet of the pressure reducing pump (231b). A first gas pipe (244) is connected to the discharge port of the pressure reducing pump (231b). The pressure reducing pump (231b) discharges the gas drawn in from the first adsorption cylinder (234) and the second adsorption cylinder (235) through the suction tube (243) into the first gas pipe (244).

[0070] <Inlet Pipe> The inlet pipe (242) is a pipe that guides the air to be treated discharged by the pressurizing pump (231a) to the first adsorption cylinder (234) and the second adsorption cylinder (235). One end of the inlet pipe (242) is connected to the discharge port of the pressurizing pump (231a). The other end of the inlet pipe (242) branches into two branch pipes, one of which is connected to the first switching valve (232), and the other branch pipe is connected to the second switching valve (233).

[0071] <Suction Pipe> The suction pipe (243) is a pipe that guides the gas flowing out from the first adsorption cylinder (234) and the second adsorption cylinder (235) to the pressure reducing pump (231b). One end of the suction pipe (243) is connected to the suction port of the pressure reducing pump (231b). The other end of the suction pipe (243) branches into two branch pipes, one of which is connected to the first switching valve (232), and the other branch pipe is connected to the second switching valve (233).

[0072] <First Gas Pipe> The first gas pipe (244) is a pipe through which nitrogen-enriched gas discharged from the pressure-reducing pump (231b) flows. The first gas pipe (244) constitutes the first gas passage through which nitrogen-enriched gas flows. One end of the first gas pipe (244) is connected to the discharge port of the pressure-reducing pump (231b). The other end of the first gas pipe (244) is connected to the gas supply pipe (275).

[0073] A check valve (264) is provided in the first gas pipe (244). This check valve (264) allows gas to flow only in the direction from one end to the other of the first gas pipe (244), and blocks gas flow in the reverse direction.

[0074] <Switching Valves> The first switching valve (232) and the second switching valve (233) are each switching valves having three ports. The first switching valve (232) and the second switching valve (233) are configured to switch between a first state (shown by a solid line in Figure 3) in which the first port communicates with the second port and is blocked from the third port, and a second state (shown by a dashed line in Figure 3) in which the first port communicates with the third port and is blocked from the second port.

[0075] The first switching valve (232) has a first port connected to one end of the first suction cylinder (234). The first switching valve (232) also has a second port connected to a branch pipe of the inlet pipe (242) and a third port connected to a branch pipe of the suction pipe (243). The first switching valve (232) switches the first suction cylinder (234) between being connected to the pressurizing pump (231a) and being connected to the depressurizing pump (231b).

[0076] The second switching valve (233) has its first port connected to one end of the second suction cylinder (235). The second switching valve (233) also has a branch pipe of the inlet pipe (242) connected to its second port and a branch pipe of the suction pipe (243) connected to its third port. The second switching valve (233) switches the second suction cylinder (235) between being connected to the pressurizing pump (231a) and being connected to the depressurizing pump (231b).

[0077] <Adsorption Tubes> Each of the first adsorption tube (234) and the second adsorption tube (235) is a component comprising a cylindrical container with both ends closed and an adsorbent filled in the container. The adsorption tubes (234, 235) use the adsorbent to separate the air to be treated (in this embodiment, outside air) into oxygen-enriched gas and nitrogen-enriched gas. The first adsorption tube (234) and the second adsorption tube (235) constitute a processing unit (95) for processing outside air.

[0078] The adsorbent packed into the adsorption cylinders (234, 235) has the property of adsorbing nitrogen and water (water vapor) from the air to be treated under pressurized conditions where the pressure is higher than atmospheric pressure, and desorbing nitrogen and water under reduced pressure conditions where the pressure is lower than atmospheric pressure. An example of an adsorbent with such properties is a porous zeolite having pores with a diameter smaller than the molecular diameter of a nitrogen molecule (3.0 angstroms) and larger than the molecular diameter of an oxygen molecule (2.8 angstroms).

[0079] <Second Gas Pipe> The second gas pipe (245) comprises a main pipe (246), a first branch pipe (247a), and a second branch pipe (247b). The second gas pipe (245) constitutes a second gas passage through which oxygen-enriched gas flows.

[0080] The first branch pipe (247a) is a pipe that connects the other end of the first adsorption cylinder (234) to one end of the main pipe (246). The second branch pipe (247b) is a pipe that connects the other end of the second adsorption cylinder (235) to one end of the main pipe (246). Each of the first branch pipe (247a) and the second branch pipe (247b) is provided with one check valve (261). Each check valve (261) allows airflow in the direction of outflow from the corresponding adsorption cylinder (234, 235) and blocks airflow in the reverse direction.

[0081] As described above, the first branch pipe (247a) and the second branch pipe (247b) are connected to one end of the main pipe (246). The other end of the main pipe (246) is connected to the gas discharge pipe (276), which will be described later. The main pipe (246) is provided with an orifice (263) and a check valve (262) in that order from one end to the other. The check valve (262) allows air to flow from one end to the other of the main pipe (246) and blocks air to flow in the reverse direction.

[0082] <Purge Pipe> A purge pipe (250) is connected to each of the first branch pipe (247a) and the second branch pipe (247b) of the second gas pipe (245). One end of the purge pipe (250) is connected to the first branch pipe (247a), and the other end is connected to the second branch pipe (247b). One end of the purge pipe (250) is connected between the first adsorption cylinder (234) and the check valve (261) in the first branch pipe (247a). The other end of the purge pipe (250) is connected between the second adsorption cylinder (235) and the check valve (261) in the second branch pipe (247b).

[0083] A purge valve (251) is provided in the purge pipe (250). The purge valve (251) is an on / off valve consisting of a solenoid valve. The purge valve (251) is opened when equalizing the pressure between the first adsorption cylinder (234) and the second adsorption cylinder (235). In addition, one orifice (252) is provided on each side of the purge valve (251) in the purge pipe (250).

[0084] <Exhaust Connection Pipe> An exhaust connection pipe (271) is connected to the first gas pipe (244). One end of the exhaust connection pipe (271) is connected to the first gas pipe (244), and the other end is connected to the second gas pipe (245). One end of the exhaust connection pipe (271) is connected between the pressure reducing pump (231b) and the check valve (264) in the first gas pipe (244). The other end of the exhaust connection pipe (271) is connected to one end of the gas discharge pipe (276).

[0085] A gas discharge valve (272) is provided in the exhaust connecting pipe (271). The gas discharge valve (272) is an on / off valve consisting of a solenoid valve. When the gas discharge valve (272) is opened, the nitrogen-enriched gas flowing through the first gas pipe (244) is discharged to the outside of the container body (2).

[0086] <Gas Supply Pipe> As described above, the first gas pipe (244) is connected to one end of the gas supply pipe (275). The gas supply pipe (275) extends to the outside of the unit case (201). The other end of the gas supply pipe (275) opens downstream of the internal fan (35) in the internal air passage (29) of the transport refrigeration unit (10). The gas supply pipe (275) is a pipe for introducing the gas that flows in from one end into the inside of the container body (2).

[0087] A gas supply valve (273) is provided in the gas supply pipe (275). The gas supply valve (273) is an on / off valve consisting of a solenoid valve.

[0088] <Gas discharge pipe> As described above, one end of the gas discharge pipe (276) is connected to the main pipe (246) of the second gas pipe (245) and the exhaust connecting pipe (271). The gas discharge pipe (276) extends to the outside of the unit case (201). The other end of the gas discharge pipe (276) opens to the external equipment room (28) of the transport container (1). The gas discharge pipe (276) is a pipe for discharging the gas that has flowed in from one end to the outside of the container body (2).

[0089] <Measuring Piping> Measuring piping (281) is connected to the first gas pipe (244). Measuring piping (281) is the piping that connects the first gas pipe (244) to the sensor unit (160). One end of measuring piping (281) is connected to the downstream side of the check valve (264) in the first gas pipe (244). The other end of measuring piping (281) is connected to the sensor unit (160).

[0090] A measuring valve (282) is provided in the measuring piping (281). The measuring valve (282) is a solenoid valve. The measuring valve (282) is opened when air flowing through the first gas pipe (244) is sent to the sensor unit (160).

[0091] <Bypass Pipe> A bypass connecting pipe (255) is connected to the inlet pipe (242). The bypass connecting pipe (255) is a pipe that bypasses the first adsorption cylinder (234) and the second adsorption cylinder (235) to supply outside air to the storage space (5) of the transport container (1). One end of the bypass connecting pipe (255) is connected between the branching point of the inlet pipe (242) and the pressurizing pump (231a). The other end of the bypass connecting pipe (255) is connected to one end of the gas supply pipe (275).

[0092] A bypass valve (256) is provided in the bypass connecting pipe (255). The bypass valve (256) is an on / off valve consisting of a solenoid valve. This bypass valve (256) is opened when the outside air discharged by the pressurizing pump (231a) is supplied to the storage space (5) without changing its composition.

[0093] <Sensor Unit> The sensor unit (160) comprises an oxygen sensor (161), a carbon dioxide sensor (162), and a sensor case (163). The sensor unit (160) is a detector that detects the concentration of components in the air inside the chamber. The sensor unit (160) is installed in the secondary flow path (29b) of the internal air flow path (29).

[0094] The oxygen sensor (161) is a zirconia current type sensor that measures the oxygen concentration of a gas mixture such as air. The carbon dioxide sensor (162) is a non-dispersive infrared (NDIR) type sensor that measures the carbon dioxide concentration of a gas mixture such as air. The oxygen sensor (161) and the carbon dioxide sensor (162) are housed in a sensor case (163).

[0095] The sensor case (163) is a box-shaped component. The sensor case (163) is equipped with an air filter (164). The air filter (164) is a membrane filter for capturing dust and other particles contained in the air inside the chamber. The air filter (164) filters the air inside the chamber that flows into the sensor case (163).

[0096] A measuring pipe (281) is connected to the sensor case (163). An outlet pipe (165) is also connected to the sensor case (163). The outlet pipe (165) has an inlet end connected to the sensor case (163) and an outlet end that opens upstream of the internal fan (35) in the internal air passage (29). In other words, the outlet end of the outlet pipe (165) opens into the primary passage (29a) of the internal air passage (29).

[0097] When the measuring valve (282) is closed, the air inside the storage chamber flows through the sensor case (163). Specifically, the air inside the storage chamber flows through the secondary flow path (29b) of the storage chamber air passage (29), passes through the air filter (164) and flows into the sensor case (163), then passes through the sensor case (163) and flows through the outlet pipe (165) and into the primary flow path (29a) of the storage chamber air passage (29). Therefore, when the measuring valve (282) is closed, the oxygen sensor (161) measures the oxygen concentration of the air inside the storage chamber, and the carbon dioxide sensor (162) measures the carbon dioxide concentration of the air inside the storage chamber.

[0098] On the other hand, when the measuring valve (282) is open, the gas flowing through the measuring pipe (281) flows inside the sensor case (163). Specifically, the gas flowing through the first gas pipe (244) or the bypass connecting pipe (255) flows through the measuring pipe (281) into the sensor case (163), passes through the sensor case (163), flows through the outlet pipe (165), and flows into the primary flow path (29a) of the internal air passage (29). Therefore, when the measuring valve (282) is open, the oxygen sensor (161) measures the oxygen concentration of the gas that has flowed from the measuring pipe (281) into the sensor case (163), and the carbon dioxide sensor (162) measures the carbon dioxide concentration of the gas that has flowed from the measuring pipe (281) into the sensor case (163).

[0099] <Ventilation Exhaust Pipe> The ventilation exhaust pipe (150) is a pipe for discharging the internal air of the transport container (1) to the outside space. The ventilation exhaust pipe (150) penetrates the external wall (21) and internal wall (22) of the transport refrigeration unit (10). A ventilation exhaust valve (151) is provided in the ventilation exhaust pipe (150). The ventilation exhaust valve (151) is an on / off valve consisting of a solenoid valve.

[0100] -Gas supply operation of the gas supply device- The gas supply device (100) performs a gas supply operation. The gas supply operation is the operation of generating supply gas by processing the outside air and supplying the generated supply gas to the storage space (5) of the storage compartment (2). During the gas supply operation, the ventilation exhaust valve (151) is opened.

[0101] In the gas supply operation, the gas supply device (100) repeatedly alternates between the first operation and the second operation. The gas supply device (100) repeatedly alternates between the first operation and the second operation with a predetermined switching time (for example, 14 seconds). As a result, in the processing unit (95) of the gas supply device (100), the outside air is separated into nitrogen-enriched gas and oxygen-enriched gas. In the gas supply operation, the gas supply device (100) supplies the nitrogen-enriched gas as the supply gas to the storage space (5) of the storage compartment (2).

[0102] <First Operation> As shown in Figure 6, in the first operation, the first switching valve (232) is set to the first state and the second switching valve (233) is set to the second state. Also in the first operation, the purge valve (251), the bypass valve (256), and the measuring on / off valve (282) are held in the closed state. In the first operation, the air pump (231) is activated and an suction operation is performed on the first suction cylinder (234) and a detachment operation is performed on the second suction cylinder (235).

[0103] The pressurizing pump (231a) draws in outside air (atmosphere) from the outside air pipe (241), pressurizes it, and supplies the pressurized outside air to the first adsorption cylinder (234). In the first adsorption cylinder (234), nitrogen and water (water vapor) contained in the supplied outside air are adsorbed by the adsorbent. As a result, oxygen-enriched gas with a lower nitrogen concentration and a higher oxygen concentration than the outside air is produced in the first adsorption cylinder (234). The oxygen-enriched gas flows out from the first adsorption cylinder (234) to the first branch pipe (247a) of the second gas pipe (245), and is then discharged to the outside space (6) through the gas discharge pipe (276).

[0104] Meanwhile, the depressurizing pump (231b) draws gas from the second adsorption cylinder (235). In the second adsorption cylinder (235), the internal pressure decreases, causing nitrogen and water to desorb from the adsorbent. As a result, nitrogen-enriched gas is generated in the second adsorption cylinder (235) with a higher nitrogen concentration and lower oxygen concentration than the outside air. The nitrogen-enriched gas flows from the second adsorption cylinder (235) into the suction pipe (243) and is drawn into the depressurizing pump (231b). The depressurizing pump (231b) pressurizes the drawn-in nitrogen-enriched gas and discharges it into the first gas pipe (244). The nitrogen-enriched gas flowing through the first gas pipe (244) is supplied to the storage space (5) of the storage unit (2) through the gas supply pipe (275).

[0105] <Second Operation> As shown in Figure 7, in the second operation, the first switching valve (232) is set to the second state and the second switching valve (233) is set to the first state. Also in the second operation, the purge valve (251), the bypass valve (256), and the measuring on / off valve (282) are held in the closed state. Then, in the second operation, the air pump (231) is activated and a detachment operation targeting the first suction cylinder (234) and an suction operation targeting the second suction cylinder (235) are performed.

[0106] The pressurizing pump (231a) draws in outside air (atmosphere) from the outside air pipe (241), pressurizes it, and supplies the pressurized outside air to the second adsorption cylinder (235). In the second adsorption cylinder (235), nitrogen and water (water vapor) contained in the supplied outside air are adsorbed by the adsorbent. As a result, oxygen-enriched gas with a lower nitrogen concentration and a higher oxygen concentration than the outside air is produced in the second adsorption cylinder (235). The oxygen-enriched gas flows out from the second adsorption cylinder (235) to the second branch pipe (247b) of the second gas pipe (245), and is then discharged to the outside space (6) through the gas discharge pipe (276).

[0107] Meanwhile, the depressurizing pump (231b) draws gas from the first adsorption cylinder (234). In the first adsorption cylinder (234), the internal pressure decreases, causing nitrogen and water to desorb from the adsorbent. As a result, nitrogen-enriched gas is generated in the first adsorption cylinder (234) with a higher nitrogen concentration and lower oxygen concentration than the outside air. The nitrogen-enriched gas flows from the first adsorption cylinder (234) into the suction pipe (243) and is drawn into the depressurizing pump (231b). The depressurizing pump (231b) pressurizes the drawn-in nitrogen-enriched gas and discharges it into the first gas pipe (244). The nitrogen-enriched gas flowing through the first gas pipe (244) is supplied to the storage space (5) of the storage unit (2) through the gas supply pipe (275).

[0108] -Outside air supply operation of the gas supply device- The gas supply device (100) performs an outside air supply operation. The outside air supply operation is the operation of supplying outside air, which is the atmosphere, to the storage space (5) of the storage compartment (2) without changing its composition.

[0109] As shown in Figure 8, during the outside air supply operation, both the first switching valve (232) and the second switching valve (233) are set to the second state. Also, during the outside air supply operation, the gas supply valve (273) and the bypass valve (256) are held in the open state, and the remaining on-off valves (251, 272, 282) are held in the closed state. In addition, during the outside air supply operation, the air pump (231) is activated and the ventilation exhaust valve (151) is opened.

[0110] The pressurizing pump (231a) draws in outside air (atmosphere) from the outside air pipe (241), pressurizes it, and discharges the pressurized outside air to the inlet pipe (242). The outside air discharged from the pressurizing pump (231a) flows sequentially through the inlet pipe (242), the bypass connecting pipe (255), and the gas supply pipe (275) and is supplied to the internal air passage (29). In this way, during outside air supply operation, the outside air discharged from the pressurizing pump (231a) is supplied to the storage space (5) without passing through the first adsorption cylinder (234) and the second adsorption cylinder (235). Therefore, during outside air supply operation, air with the same composition as the atmosphere is supplied to the storage space (5) of the transport container (1).

[0111] The pressure reducing pump (231b) draws gas from both the first adsorption cylinder (234) and the second adsorption cylinder (235), and discharges the drawn-in gas to the first gas pipe (244). The gas discharged by the pressure reducing pump (231b) to the first gas pipe (244) flows into the gas supply pipe (275) and, together with the outside air that flows into the gas supply pipe (275) from the bypass connecting pipe (255), is supplied to the internal air passage (29).

[0112] When the depressurizing pump (231b) draws gas from the first adsorption cylinder (234) and the second adsorption cylinder (235), the pressure in the first adsorption cylinder (234) and the second adsorption cylinder (235) gradually decreases. Then, once the duration of the outside air supply operation exceeds a certain period of time (for example, 45 seconds), the flow rate of gas drawn in by the depressurizing pump (231b) becomes virtually zero.

[0113] - Shutdown operation of the gas supply device - The gas supply device (100) performs a shutdown operation. The shutdown operation is an operation in which the supply of gas and outside air to the storage space (5) is stopped, and the oxygen concentration of the air inside the storage space is monitored.

[0114] During the pause operation, the air pump (231) stops, and the gas supply valve (273) and ventilation exhaust valve (151) are kept closed. Because the air pump (231) is stopped, the gas supply device (100) does not supply either supply gas or outside air to the storage space (5). When fresh produce stored in the storage space (5) respires, the oxygen concentration of the air inside the storage space gradually decreases. Therefore, during the pause operation, the gas supply device (100) monitors the readings of the oxygen sensor (161).

[0115] -Gas Separation Device- The gas discharge device (300) will be explained with reference to Figure 9. The gas discharge device (300) is a so-called PSA (Pressure Swing Adsorption) type gas separation device.

[0116] The gas discharge device (300) comprises an air filter (305), an air pump (310), a pair of switching valves (316, 317), and a pair of suction cylinders (321, 322). Although not shown in the illustration, the air filter (305), air pump (310), pair of switching valves (316, 317), and pair of suction cylinders (321, 322) are housed in a single casing. The gas discharge device (300) also comprises an internal pipe (331), an inlet pipe (332), an outlet pipe (334), a gas supply pipe (341), a gas discharge pipe (342), and a bypass pipe (345).

[0117] The gas exhaust device (300) separates carbon dioxide from the air inside the storage space (5) by processing the air inside the storage space. Specifically, the gas exhaust device (300) separates the air inside the storage space into exhaust gas and return gas. The exhaust gas is a gas that contains almost only carbon dioxide. The return gas is a gas that mainly contains nitrogen and oxygen.

[0118] <Air filter, internal air pipe> The air filter (305) is a filter for capturing dust and other particles contained in the air inside the chamber. The air filter (305) in this embodiment is a membrane filter that has breathability and waterproofing properties.

[0119] The internal air pipe (331) is a pipe that sends internal air to the air filter (305). One end of the internal air pipe (331) opens to, for example, the primary air passage (29a) of the internal air passage (29) of the transport refrigeration unit (10) and communicates with the storage space (5) of the container body (2). The other end of the internal air pipe (331) is connected to the air filter (305).

[0120] <Air Pump> The air pump (310) comprises a pressure pump (311), a pressure reducing pump (312), and a drive motor (313). The pressure pump (311) and the pressure reducing pump (312) each draw in and discharge air. The pressure pump (311) and the pressure reducing pump (312) are connected to the drive shaft of a single drive motor (313). In the air pump (310), both the pressure pump (311) and the pressure reducing pump (312) are driven by a single drive motor (313). The maximum discharge flow rate of the pressure reducing pump (312) is less than the maximum discharge flow rate of the pressure reducing pump (231b) of the air pump (231) of the gas supply device (100).

[0121] An air filter (305) is connected to the intake port of the pressure pump (311) via piping. One end of an inlet pipe (332) is connected to the discharge port of the pressure pump (311). The pressure pump (311) is the supply unit. The pressure pump (311) supplies the air drawn in from the air filter (305) to the first adsorption cylinder (321) and the second adsorption cylinder (322) through the inlet pipe (332).

[0122] During the process in which the pressurizing pump (311) compresses the air inside the chamber, the temperature of the air inside the chamber rises. Therefore, the pressurizing pump (311) also functions as a heating unit (350) that heats the air inside the chamber supplied to the suction cylinders (321, 322). In the pressurizing pump (311), which is the heating unit (350), the temperature of the air drawn in rises to above the reference temperature. In this embodiment, the reference temperature is 40°C.

[0123] A suction pipe (333) is connected to the inlet of the pressure reducing pump (312). A gas discharge pipe (342) is connected to the outlet of the pressure reducing pump (312). The pressure reducing pump (312) is the discharge section. The pressure reducing pump (312) discharges the exhaust gas, which has been drawn in from the first adsorption cylinder (321) and the second adsorption cylinder (322) through the suction pipe (333), to the gas discharge pipe (342).

[0124] <Inlet pipe> The inlet pipe (332) is a pipe that guides the air inside the chamber discharged by the pressurizing pump (311) to the first suction cylinder (321) and the second suction cylinder (322). One end of the inlet pipe (332) is connected to the discharge port of the pressurizing pump (311). The other end of the inlet pipe (332) branches into two branch pipes, one of which is connected to the first switching valve (316) and the other branch pipe is connected to the second switching valve (317).

[0125] <Suction Pipe> The suction pipe (333) is a pipe that guides the exhaust gas flowing out from the first adsorption cylinder (321) and the second adsorption cylinder (322) to the pressure reducing pump (312). One end of the suction pipe (333) is connected to the suction port of the pressure reducing pump (312). The other end of the suction pipe (333) branches into two branch pipes, one of which is connected to the first switching valve (316), and the other branch pipe is connected to the second switching valve (317).

[0126] <Switching Valves> The first switching valve (316) and the second switching valve (317) are each switching valves having three ports. The first switching valve (316) and the second switching valve (317) are configured to switch between a first state (shown by a solid line in Figure 9) in which the first port communicates with the second port and is blocked from the third port, and a second state (shown by a dashed line in Figure 9) in which the first port communicates with the third port and is blocked from the second port.

[0127] The first switching valve (316) has a first port connected to one end of the first suction cylinder (321). The first switching valve (316) also has a second port to which a branch pipe of the inlet pipe (332) is connected, and a third port to which a branch pipe of the suction pipe (333) is connected. The first switching valve (316) switches the first suction cylinder (321) between being connected to the pressure pump (311) and being connected to the pressure reducing pump (312).

[0128] The second switching valve (317) has its first port connected to one end of the second suction cylinder (322). The second switching valve (317) also has a branch pipe of the inlet pipe (332) connected to its second port and a branch pipe of the suction pipe (333) connected to its third port. The second switching valve (317) switches the second suction cylinder (322) between being connected to the pressure pump (311) and being connected to the pressure reducing pump (312).

[0129] <Adsorption Tubes> Each of the first adsorption tube (321) and the second adsorption tube (322) is a component comprising a cylindrical container with both ends closed and an adsorbent filled in the container. The adsorption tubes (321, 322) use the adsorbent to separate the air inside the chamber, which is the air to be treated, into exhaust gas and return gas.

[0130] The adsorbent packed into the adsorption cylinders (321, 322) has the property of adsorbing carbon dioxide from the air inside the chamber when the pressure is above atmospheric pressure, and desorbing carbon dioxide when the pressure is below atmospheric pressure. The adsorbent in this embodiment is a metal-organic framework (MOF). A metal-organic framework is a porous material containing metal ions and organic ligands. Generally, the two-dimensional and three-dimensional structures of metal-organic frameworks can be freely designed. The metal-organic framework used as the adsorbent in this embodiment is designed to have a structure suitable for carbon dioxide adsorption.

[0131] <Outlet Pipe> The outlet pipe (334) is the piping through which the return gas flowing out from the first adsorption cylinder (321) and the second adsorption cylinder (322) flows. One end of the outlet pipe (334) is connected to the gas supply pipe (341). The outlet pipe (334) branches into two branch pipes at the other end, with one branch pipe connected to the other end of the first adsorption cylinder (321) and the other branch pipe connected to the other end of the second adsorption cylinder (322). Each branch pipe of the outlet pipe (334) is provided with one check valve (335). Each check valve (335) allows the flow of gas flowing out from the corresponding adsorption cylinder (321, 322) and prevents the flow of gas in the reverse direction.

[0132] <Gas supply pipe> An outlet pipe (334) is connected to one end of the gas supply pipe (341). One end of the gas supply pipe (341) opens to, for example, the secondary flow path (29b) of the internal air passage (29) of the transport refrigeration unit (10), and communicates with the storage space (5) of the container body (2). The gas supply pipe (341) supplies the gas that flows in from one end to the storage space (5).

[0133] <Gas discharge pipe> As described above, one end of the gas discharge pipe (342) is connected to the discharge port of the pressure reducing pump (312). The other end of the gas discharge pipe (342) opens to the external equipment room (28) of the transport container (1). The gas discharge pipe (342) discharges the exhaust gas discharged from the pressure reducing pump (312) to the outside of the transport container (1).

[0134] <Bypass Pipe> A bypass pipe (345) is connected to the inlet pipe (332). One end of the bypass pipe (345) is connected to the inlet pipe (332). The other end of the bypass pipe (345) is connected downstream of the check valve (335) in the gas supply pipe (341). The bypass pipe (345) is a pipe that allows the air inside the chamber discharged from the pressurizing pump (311) to flow directly into the gas supply pipe (341). The air inside the chamber flowing through the bypass pipe (345) flows into the gas supply pipe (341) without passing through the first adsorption cylinder (321) and the second adsorption cylinder (322).

[0135] A bypass valve (346) is provided in the bypass pipe (345). The bypass valve (346) is an on / off valve consisting of a solenoid valve. When the bypass valve (346) is open, air from inside the storage unit flows through the bypass pipe (345), and when the bypass valve (346) is closed, air from inside the storage unit does not flow through the bypass pipe (345).

[0136] -Gas discharge operation of the gas discharge device- The gas discharge device (300) performs a gas discharge operation. The gas discharge operation is the operation of discharging the exhaust gas (carbon dioxide) separated from the air inside the container to the outside of the transport container (1). During the gas discharge operation, the bypass valve (346) is held in the closed position.

[0137] During the gas discharge operation, the gas discharge device (300) repeatedly alternates between the first operation and the second operation. The gas discharge device (300) repeatedly alternates between the first operation and the second operation with a predetermined switching time (for example, 14 seconds). As a result, the gas discharge device (300) separates the air inside the storage into discharge gas and return gas. During the gas discharge operation, the gas discharge device (300) discharges the discharge gas to the outside of the transport container (1) and sends the return gas back to the storage space (5).

[0138] <First Operation> As shown in Figure 10, in the first operation, the first switching valve (316) is set to the first state and the second switching valve (317) is set to the second state. In the first operation, the air pump (310) is activated and performs an suction operation targeting the first suction cylinder (321) and a detachment operation targeting the second suction cylinder (322).

[0139] The pressurizing pump (311) draws in air from the internal air pipe (331) and pressurizes it. As described above, the temperature of the air inside the chamber rises during the process in which the pressurizing pump (311) compresses the air inside the chamber. In the gas discharge device (300) of this embodiment, the pressurizing pump (311) draws in air inside the chamber at a temperature approximately equal to the set temperature inside the chamber (14°C in this embodiment) and discharges air inside the chamber at a temperature above the reference temperature (for example, 50°C). In the gas discharge device (300) of this embodiment, it is desirable that the temperature of the air inside the chamber discharged by the pressurizing pump (311) is between 40°C and 60°C.

[0140] Air discharged from the pressurizing pump (311) flows into the first adsorption cylinder (321) through the first switching valve (316). The first adsorption cylinder (321) becomes pressurized, with an internal pressure higher than atmospheric pressure. In the first adsorption cylinder (321), carbon dioxide contained in the incoming air is adsorbed by the adsorbent. As a result, a return gas with a lower carbon dioxide concentration than the air inside the chamber is generated in the first adsorption cylinder (321). The return gas flows out of the first adsorption cylinder (321) into the outlet pipe (334), and is then sent back to the storage space (5) through the gas supply pipe (341).

[0141] Meanwhile, the depressurizing pump (312) communicates with the second adsorption cylinder (322) via the second switching valve (317). The depressurizing pump (312) draws gas from the second adsorption cylinder (322). The second adsorption cylinder (322) becomes a depressurized state with an internal pressure lower than atmospheric pressure. Carbon dioxide is released from the adsorbent in the second adsorption cylinder (322). As a result, exhaust gas with a higher carbon dioxide concentration than the air inside the container is generated in the second adsorption cylinder (322). The exhaust gas flows from the second adsorption cylinder (322) into the suction pipe (333) and is drawn into the depressurizing pump (312). Subsequently, the exhaust gas is discharged from the depressurizing pump (312) to the gas discharge pipe (342) and discharged to the outside of the transport container (1) through the gas discharge pipe (342).

[0142] <Second Operation> As shown in Figure 11, in the second operation, the first switching valve (316) is set to the second state and the second switching valve (317) is set to the first state. In the second operation, the air pump (310) is activated and performs an suction operation targeting the second suction cylinder (322) and a detachment operation targeting the first suction cylinder (321).

[0143] The pressurizing pump (311) draws in air from the internal air pipe (331) and pressurizes it. Similar to the first operation, as the pressurizing pump (311) compresses the air inside the chamber, the temperature of the air inside the chamber rises to above the reference temperature.

[0144] Air discharged from the pressurizing pump (311) flows into the second adsorption cylinder (322) through the second switching valve (317). The second adsorption cylinder (322) becomes pressurized, with an internal pressure higher than atmospheric pressure. In the second adsorption cylinder (322), carbon dioxide contained in the incoming air is adsorbed by the adsorbent. As a result, a return gas with a lower carbon dioxide concentration than the air inside the chamber is generated in the second adsorption cylinder (322). The return gas flows out of the second adsorption cylinder (322) into the outlet pipe (334), and is then sent back to the storage space (5) through the gas supply pipe (341).

[0145] Meanwhile, the depressurizing pump (312) communicates with the first adsorption cylinder (321) via the first switching valve (316). The depressurizing pump (312) draws gas from the first adsorption cylinder (321). The first adsorption cylinder (321) becomes a depressurized state with an internal pressure lower than atmospheric pressure. Carbon dioxide is desorbed from the adsorbent in the first adsorption cylinder (321). As a result, exhaust gas with a higher carbon dioxide concentration than the air inside the chamber is generated in the first adsorption cylinder (321). The exhaust gas flows from the first adsorption cylinder (321) into the suction pipe (333) and is drawn into the depressurizing pump (312). Subsequently, the exhaust gas is discharged from the depressurizing pump (312) to the gas discharge pipe (342) and discharged to the outside of the transport container (1) through the gas discharge pipe (342).

[0146] -Preparation Operation of Gas Discharge Device- The gas discharge device (300) performs a preparatory operation. The preparatory operation is the operation of returning the air drawn in by the air pump (310) to the storage space (5) of the storage compartment (2) without sending it to the adsorption cylinders (321, 322). As will be described in more detail later, the gas discharge device (300) performs a preparatory operation when the air pump (310) is started, and performs a gas discharge operation after the preparatory operation is completed.

[0147] As shown in Figure 12, during the preparation operation, both the first switching valve (316) and the second switching valve (317) are set to the second state. Also, during the preparation operation, the bypass valve (346) is held in the open state.

[0148] The pressurizing pump (311) draws in air from the internal air pipe (331), pressurizes it, and discharges the pressurized air into the inlet pipe (332). The air discharged from the pressurizing pump (311) flows sequentially through the inlet pipe (332), the bypass pipe (345), and the gas supply pipe (341), and is supplied to the internal air passage (29) of the transport refrigeration unit (10). In this way, during the preparation operation, the air discharged from the pressurizing pump (311) is sent back to the storage space (5) without passing through the first adsorption cylinder (321) and the second adsorption cylinder (322).

[0149] The pressure reducing pump (312) draws in gas from both the first adsorption cylinder (321) and the second adsorption cylinder (322), and discharges the drawn-in gas to the gas discharge pipe (342). The gas discharged by the pressure reducing pump (312) is discharged to the outside of the transport container (1) through the gas discharge pipe (342).

[0150] -Characteristics of the Adsorbent- The characteristics of the adsorbent filled in the adsorption cylinders (321, 322) will be explained with reference to Figure 16. Figure 16 is an example of an adsorption isotherm of the adsorbent.

[0151] Generally, the amount of gas adsorbed by an adsorbent increases as the pressure of the gas in contact with the adsorbent increases. Furthermore, the amount of gas adsorbed by an adsorbent also increases as the temperature of the adsorbent increases. In Figure 16, Ta, Tb, and Tc represent the temperatures of the adsorbent, increasing in the order Ta, Tb, and Tc (Ta < Tb < Tc).

[0152] As shown in Figure 16, the trend of changes in adsorption amount in response to pressure changes differs depending on the temperature of the adsorbent. Therefore, there is an appropriate temperature range for the adsorbent during the gas discharge operation of the gas discharge device (300). This point will be explained.

[0153] In Figure 16, pressure P1 is the internal pressure of the adsorption cylinders (321, 322) being subjected to the adsorption operation, and is substantially equal to the pressure of the internal air discharged by the pressurizing pump (311). Pressure P2 is the internal pressure of the adsorption cylinders (321, 322) being subjected to the detachment operation, and is substantially equal to the pressure of the exhaust gas (carbon dioxide) drawn in by the decompression pump (312).

[0154] When the adsorbent temperature is Ta, the difference between the adsorbent amount Ma2 at pressure P2 and the adsorbent amount Ma1 at pressure P1 is ΔMa (ΔMa = Ma2 - Ma1). When the adsorbent temperature is Tb, the difference between the adsorbent amount Mb2 at pressure P2 and the adsorbent amount Mb1 at pressure P1 is ΔMb (ΔMb = Mb2 - Mb1). When the adsorbent temperature is Tc, the difference between the adsorbent amount Mc2 at pressure P2 and the adsorbent amount Mc1 at pressure P1 is ΔMc (ΔMc = Mc2 - Mc1). The adsorption difference ΔMb when the adsorbent temperature is Tb is greater than the adsorption difference ΔMa when the adsorbent temperature is Ta (ΔMb > ΔMa), and is greater than the adsorption difference ΔMc when the adsorbent temperature is Tc (ΔMb > ΔMc).

[0155] The larger the difference ΔM between the amount of adsorption at pressure P2 and the amount of adsorption at pressure P1, the greater the amount of exhaust gas (carbon dioxide) that the decompression pump (312) draws from the adsorption cylinders (321, 322) in a single first or second operation. Therefore, the larger the difference ΔM between the amount of adsorption at pressure P2 and the amount of adsorption at pressure P1, the greater the amount of carbon dioxide that the gas exhaust device (300) discharges from the storage space (5) per unit time during the gas discharge operation. Consequently, in the example shown in Figure 16, the capacity of the gas exhaust device (300) to discharge carbon dioxide is higher when the adsorbent temperature is Tb than when the adsorbent temperature is Ta or when the adsorbent temperature is Tc.

[0156] Thus, in a gas discharge device (300) equipped with an adsorbent, there is an appropriate range for the temperature of the adsorbent during gas discharge operation. In the gas discharge device (300) of this embodiment, it is desirable to maintain the temperature of the adsorbent during gas discharge operation in a range of, for example, 40°C to 60°C. Therefore, in the gas discharge device (300) of this embodiment, the temperature of the air inside the chamber discharged by the pressurizing pump (311) is set to a range of 40°C to 60°C.

[0157] -Location of the gas discharge device- As shown in Figure 13, the gas discharge device (300) is installed in the interior space of the transport container (1). The gas discharge device (300) is also installed outside the casing (20) of the transport refrigeration unit (10). Specifically, the gas discharge device (300) is installed between the side of the casing (20) of the transport refrigeration unit (10) and the side wall of the container body (2).

[0158] As described above, in order for the gas exhaust device (300) to stably exhibit its carbon dioxide emission capacity, it is desirable to maintain the temperature of the adsorbent within an appropriate temperature range. Therefore, the gas exhaust device (300) is installed in the space between the side of the casing (20) of the transport refrigeration device (10) and the side wall of the container body (2).

[0159] The space in which this gas exhaust device (300) is installed has relatively little airflow and a relatively stable temperature. In this embodiment, the gas exhaust device (300) is installed in a location where temperature fluctuations are smaller than in the space outside the storage area. As a result, the temperature of the adsorbent can be kept within an appropriate temperature range, and the gas exhaust device (300) can reliably perform to its full potential.

[0160] -Controller- As shown in Figure 14, the controller (110) comprises a microcomputer (111) mounted on a control board and a memory device (112) that stores software for operating the microcomputer (111). The memory device (112) is a semiconductor memory.

[0161] The controller (110) receives the measured values ​​from the oxygen sensor (161) and the carbon dioxide sensor (162). The controller (110) uses these input measured values ​​to control the gas supply device (100) and the gas discharge device (300).

[0162] -Control of the gas supply device by the controller- The operation of the controller (110) in controlling the gas supply device (100) will be described below.

[0163] The controller (110) controls the gas supply device (100) based on the measurement value from the oxygen sensor (161). Specifically, the controller (110) controls the gas supply device (100) so that the measurement value C1m from the oxygen sensor (161) is maintained within the target oxygen concentration range.

[0164] The target oxygen concentration range is a numerical range that includes the set oxygen concentration C1s. In this embodiment, the target oxygen concentration range is between (C1s - γ) and (C1s + γ). γ is, for example, "1%". The set oxygen concentration C1s is the set value for the oxygen concentration of the air inside the storage chamber. The set oxygen concentration C1s is set to a value suitable for preserving the items stored in the storage space (5). For example, if the items stored in the storage space (5) are mangoes, the set oxygen concentration C1s is set to 5%.

[0165] If the measured value C1m from the oxygen sensor (161) is higher than the maximum value of the target oxygen concentration range (C1s + γ < C1m), the controller (110) causes the gas supply device (100) to perform a gas supply operation. During the gas supply operation, the gas supply device (100) supplies nitrogen-enriched gas to the storage space (5). As a result, the oxygen concentration of the air inside the storage space (5) decreases. When the measured value C1m from the oxygen sensor (161) drops to the maximum value of the target oxygen concentration range, the controller (110) switches the operation performed by the gas supply device (100) from gas supply operation to pause operation.

[0166] When the gas supply device (100) is in a paused state, the oxygen concentration inside the storage space (5) gradually decreases as the fresh food stored inside the storage space respires. When the measurement value C1m of the oxygen sensor (161) falls below the minimum value of the target oxygen concentration range (C1m < C1s - γ), the controller (110) switches the operation performed by the gas supply device (100) from paused state to outside air supply state.

[0167] During the outside air supply operation, the gas supply device (100) supplies outside air to the storage space (5) in its original state (in other words, without changing its composition). As a result, the oxygen concentration of the air inside the storage space increases. When the measured value C1m of the oxygen sensor (161) reaches the maximum value of the target oxygen concentration range, the controller (110) switches the operation performed by the gas supply device (100) from outside air supply operation to pause operation.

[0168] Furthermore, the controller (110) may switch the operation performed by the gas supply device (100) from pause operation to gas supply operation when the measured value C1m of the oxygen sensor (161) falls below the minimum value of the target oxygen concentration range (C1m < C1s - γ). However, in this case, the oxygen concentration of the supplied gas must be higher than the maximum value of the target oxygen concentration range.

[0169] -Control of the gas exhaust device by the controller- The operation of the controller (110) in controlling the gas exhaust device (300) will be explained.

[0170] The controller (110) controls the gas exhaust device (300) based on the measurement value from the carbon dioxide sensor (162). Specifically, the controller (110) controls the gas exhaust device (300) so that the measurement value C2m from the carbon dioxide sensor (162) is kept within the target carbon dioxide concentration range.

[0171] The target carbon dioxide concentration range is a numerical range that includes the set carbon dioxide concentration C2s. In this embodiment, the target carbon dioxide concentration range is (C2s - α) or more and (C2s + α) or less. α is, for example, "1%". The set carbon dioxide concentration C2s is set to a value suitable for the preservation of the items stored in the storage space (5). For example, if the items stored in the storage space (5) are mangoes, the set carbon dioxide concentration C2s is set to 5%.

[0172] Furthermore, the controller (110) permits the gas discharge operation of the gas discharge device (300) when the gas supply device (100) is performing a gas supply operation or an outside air supply operation, and prohibits the gas discharge operation of the gas discharge device (300) when the gas supply device (100) is performing a pause operation.

[0173] Here, the operation of the controller (110) in controlling the gas exhaust device (300) will be explained with reference to the flowchart in Figure 15. The controller (110) repeatedly performs the processes from step ST1 to step ST7 at predetermined intervals.

[0174] <Step ST1> In step ST1, the controller (110) determines whether the permission condition is met. The permission condition is that "the gas supply device (100) is performing a gas supply operation or an outside air supply operation."

[0175] The controller (110) determines the operation being performed by the gas supply device (100) based on the status of the air pump (231) of the gas supply device (100). Specifically, the controller (110) determines that the gas supply device (100) is performing a gas supply operation or an outside air supply operation when the air pump (231) of the gas supply device (100) is operating. The controller (110) also determines that the gas supply device (100) is performing a pause operation when the air pump (231) of the gas supply device (100) is stopped.

[0176] If the controller (110) determines that the permit conditions are met, it performs the process in step ST2. On the other hand, if the controller (110) determines that the permit conditions are not met, it temporarily terminates control of the gas discharge device (300).

[0177] <Step ST2> In the process of step ST2, the controller (110) determines whether the condition that "the measured value C2m of the carbon dioxide sensor (162) is higher than the maximum value of the target carbon dioxide concentration range (C2m > C2s + α)" is met. If this condition is met, the controller (110) performs the process of step ST3. On the other hand, if this condition is not met, the carbon dioxide concentration of the air inside the chamber is kept sufficiently low. Therefore, if this condition is not met, the controller (110) temporarily terminates control of the gas exhaust device (300).

[0178] <Step ST3> In the process of step ST3, the controller (110) causes the gas discharge device (300) to start a preparatory operation. The gas discharge device (300) receives a command signal from the controller (110) and starts the air pump (310). In the preparatory operation, the gas discharge device (300) does not send the air drawn in by the air pump (310) to the adsorption cylinders (321, 322), but instead sends it back to the storage space (5) in the same state.

[0179] <Step ST4> In the next step ST4, the controller (110) determines whether the condition "time t has elapsed since the gas discharge device (300) started its preparatory operation" is met. "Time t" is the time required for the temperature of the air inside the chamber discharged by the pressurizing pump (311) to reach a predetermined temperature (for example, 50°C). "Time t" is, for example, 20 minutes.

[0180] Until this condition is met, the controller (110) causes the gas discharge device (300) to continue its preparatory operation. Once this condition is met, the controller (110) performs the process of step ST5.

[0181] <Step ST5> In the process of step ST5, the controller (110) instructs the gas discharge device (300) to complete the preparation operation and start the gas discharge operation. The gas discharge device (300) receives a command signal from the controller (110) and switches the operation to be performed from the preparation operation to the gas discharge operation.

[0182] During the gas discharge operation, the gas discharge device (300) discharges carbon dioxide separated from the air inside the storage space to the outside of the transport container (1). Therefore, while the gas discharge device (300) is performing the gas discharge operation, the carbon dioxide concentration in the air inside the storage space (5) gradually decreases.

[0183] <Step ST6> In the next step ST6, the controller (110) determines whether the condition that "the measured value C2m of the carbon dioxide sensor (162) is lower than the minimum value of the target carbon dioxide concentration range (C2m < C2s - α)" is met. If this condition is met, the controller (110) performs the process of step ST7. On the other hand, if this condition is not met, the carbon dioxide concentration of the air inside the chamber has not reached the minimum value of the target carbon dioxide concentration range. Therefore, if this condition is not met, the controller (110) instructs the gas discharge device (300) to continue the gas discharge operation.

[0184] <Step ST7> In step ST7, the controller (110) stops the gas discharge device (300). As a result, the gas discharge operation of the gas discharge device (300) is completed. After that, the controller (110) temporarily terminates control of the gas discharge device (300).

[0185] -Features of the Embodiment (1)- In the gas discharge operation of the gas discharge device (300) of this embodiment, a pressurizing pump (311) that functions as a heating unit (350) discharges air from inside the chamber at a temperature above the reference temperature, and the air discharged from the pressurizing pump (311) is supplied to the adsorption cylinders (321, 322) which are the target of the adsorption operation.

[0186] Therefore, the adsorbent in the adsorption cylinders (321, 322) that are subjected to the adsorption operation is kept at a temperature suitable for separating carbon dioxide from the air inside the chamber. Specifically, the temperature of the adsorbent is kept at a temperature such that the difference between the amount of carbon dioxide adsorbed at the pressure during the adsorption operation and the amount of carbon dioxide adsorbed at the pressure during the desorption operation is relatively large. Accordingly, according to this embodiment, the temperature of the adsorbent can be kept within an appropriate range, and as a result, the amount of carbon dioxide emitted by the gas exhaust device (300) can be improved.

[0187] -Features of the Embodiment (2)- When the gas discharge device (300) is stopped for a certain period of time, the temperature of the air pump (310) of the gas discharge device (300) becomes about the same as the ambient temperature around the gas discharge device (300). The gas discharge device (300) of this embodiment is installed in the internal space of the transport container (1). Therefore, the temperature of the air pump (310) of the gas discharge device (300) becomes about the same as the ambient temperature of the storage space (5) (for example, 14°C).

[0188] Therefore, when the pressurizing pump (311) of the gas discharge device (300) is started, the temperature of the air inside the chamber discharged by the pressurizing pump (311) is relatively low. In this state, the temperature of the air inside the chamber may fall below its dew point temperature as it flows through the inlet pipe (332), and there is a risk that the water vapor contained in the air inside the chamber will condense. If the condensed water that flows into the adsorption cylinders (321, 322) along with the air inside the chamber adheres to the adsorbent, there is a risk that the adsorption performance of the adsorbent will be impaired.

[0189] In contrast, the gas discharge device (300) of this embodiment first performs a preparatory operation when started, and starts the gas discharge operation after the temperature of the air inside the chamber discharged by the pressurizing pump (311) reaches a certain level (for example, 50°C). Therefore, even at the time the gas discharge operation starts, the temperature of the air inside the chamber flowing into the adsorption cylinders (321, 322) through the introduction pipe (332) is higher than the dew point temperature of the air inside the chamber. Accordingly, according to this embodiment, it is possible to prevent condensed water from adhering to the adsorbent when the gas discharge device (300) is started, and a deterioration in the performance of the adsorbent can be avoided.

[0190] - Modifications of the Embodiment - The following modifications may be applied to the air composition adjustment system (90) of the above embodiment. The following modifications may be combined or substituted as appropriate, as long as they do not impair the function of the air composition adjustment system (90).

[0191] <First Modification> As shown in Figure 17, the gas discharge device (300) of the above embodiment may be equipped with a blower (355) instead of a pressurizing pump (311). The blower (355) is driven by a motor separate from the drive motor (313) that drives the pressure reducing pump (312). The blower (355) sucks in and blows out the air inside the chamber that has passed through the air filter (305).

[0192] The gas exhaust device (300) in this modified example includes an electric heater (351). The electric heater (351) is a heating unit (350). The electric heater (351) is installed in the inlet pipe (332) and heats the air inside the chamber blown out from the blower (355) to a standard temperature or higher.

[0193] In this modified gas exhaust device (300), the air inside the chamber, blown out from the blower (355) and heated by the electric heater (351), is supplied to the adsorption cylinders (321, 322). The pressure of the air inside the chamber supplied by the blower (355) to the adsorption cylinders (321, 322) is approximately the same as atmospheric pressure.

[0194] <Second Modification> In the air composition adjustment system (90) of the above embodiment, the gas discharge device (300) may be installed outside the container body (2). In this modification, the gas discharge device (300) is installed, for example, in the external equipment room (28) of the transport refrigeration system (10).

[0195] While embodiments and modifications have been described above, it will be understood that a variety of changes in form and details are possible without departing from the spirit and scope of the claims. Furthermore, these embodiments and modifications may be combined or substituted as appropriate, as long as they do not impair the function of the subject matter of this disclosure. In addition, the designations "first," "second," etc. in the specification and claims are used to distinguish the phrases to which these designations are attached, and do not limit the number or order of such phrases.

[0196] As described above, this disclosure is useful for air composition control systems, refrigeration equipment, and transport containers.

[0197] 1 Transport container 2 Container body (storage compartment) 10 Refrigeration unit 11 Refrigerant circuit 90 Air composition adjustment system 95 Processing unit 100 Gas supply unit 300 Gas discharge unit 311 Pressure pump (supply unit) 312 Pressure pump (discharge unit) 321 First adsorption cylinder 322 Second adsorption cylinder 350 Heating unit 351 Electric heater

Claims

1. A gas discharge device (300) for discharging carbon dioxide contained in the internal air of a storage compartment (2) to the outside of the storage compartment (2), comprising an adsorbent for adsorbing carbon dioxide, which supplies the internal air to the adsorbent and performs an adsorption operation in which carbon dioxide contained in the internal air is adsorbed onto the adsorbent, and a desorption operation in which carbon dioxide desorbed from the adsorbent is discharged to the outside of the storage compartment (2) by reducing the pressure of the adsorbent, wherein in the adsorption operation, the temperature of the internal air supplied to the adsorbent is at or above a reference temperature.

2. The gas discharge device according to claim 1, further comprising a heating unit (350) for heating the internal air supplied to the adsorbent, wherein in the adsorption operation, the internal air heated by the heating unit (350) is supplied to the adsorbent.

3. The gas discharge device according to claim 2, wherein the heating unit (350) is a pressurizing pump (311) that heats the air inside the chamber by compressing it.

4. The gas discharge device according to claim 3, wherein the pressurizing pump (311) discharges the air inside the storage chamber and performs a preparatory operation to send it back into the storage chamber (2) without supplying it to the adsorbent, the preparatory operation is started when the pressurizing pump (311) is started, and the adsorption operation is started after the completion of the preparatory operation.

5. The gas discharge device according to claim 4, wherein the above preparation operation is performed until the temperature of the air inside the chamber discharged by the pressurizing pump (311) reaches or exceeds the reference temperature.

6. The gas discharge device according to claim 2, wherein the heating unit (350) is an electric heater (351) that heats the air inside the chamber.

7. The gas discharge device according to claim 1, 2, or 6, further comprising: a supply unit that sucks in the air inside the storage chamber and supplies it to the adsorbent during the adsorption operation; and a discharge unit (312) that sucks in the carbon dioxide desorbed from the adsorbent and discharges it to the outside of the storage chamber (2) during the desorption operation.

8. The gas discharge device according to any one of claims 3 to 5, comprising: a supply unit that sucks in the air inside the chamber and supplies it to the adsorbent during the adsorption operation; and a discharge unit (312) that sucks in the carbon dioxide desorbed from the adsorbent and discharges it to the outside of the storage chamber (2) during the desorption operation, wherein the pressurizing pump (311) also serves as the supply unit.

9. The gas discharge device according to claim 7 or 8, comprising an adsorption cylinder (321, 322) filled with the above-mentioned adsorbent, wherein the discharge unit (312) is a depressurizing pump that sucks carbon dioxide from the adsorption cylinder (321, 322) and depressurizes the adsorption cylinder (321, 322).

10. The gas discharge device according to any one of claims 1 to 9, wherein the above reference temperature is 40°C.

11. The gas discharge device according to any one of claims 1 to 10, wherein the adsorbent is a metal-organic structure.

12. The gas discharge device according to any one of claims 1 to 11, wherein the adsorbent is installed inside the storage compartment (2).

13. An air composition adjustment system (90) for adjusting the composition of the internal air inside a storage compartment (2), comprising: a gas discharge device (300) according to any one of claims 1 to 12; and a gas supply device (100) having a processing unit (95) that processes external air outside the storage compartment (2) to generate a supply gas with a different composition from the external air, and supplying the supply gas generated in the processing unit (95) to the inside of the storage compartment (2).

14. A refrigeration apparatus comprising an air composition adjustment system (90) according to claim 13, and a refrigerant circuit (11) that performs a refrigeration cycle to adjust the temperature of the air inside the chamber.

15. A refrigeration device comprising: an air composition adjustment system (90) according to claim 13; a refrigerant circuit (11) that performs a refrigeration cycle having an internal heat exchanger (15) that exchanges heat between the refrigerant and the internal air; and an internal air passage (29) through which the internal heat exchanger (15) is provided and the internal air flows, wherein the gas discharge device (300) of the air composition adjustment system (90) is installed in a position that is inside the storage compartment (2) and outside the internal air passage (29).

16. A transport container comprising a refrigeration device (10) as described in claim 15 and a container body constituting the storage compartment (2) described above.

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