Air composition adjustment device and transport container

Abstract

To provide an air composition control device that can reduce the range of changes in the composition of the air inside a storage chamber. [Solution] The controller (110) performs flow rate control during the operation of the air transport unit (231, 291) to adjust the flow rate of the first air so that the concentration of components in the air inside the chamber reaches a set value.

Description

【Technical Field】 【0001】 The present disclosure relates to an air composition regulating device and a transportation container. 【Background Art】 【0002】 There is an air composition regulating device that regulates the composition of air in a storage such as a container. The air composition regulating device of Patent Document 1 adjusts the composition of outdoor air, specifically, the oxygen concentration, carbon dioxide concentration, etc., by an adsorption cylinder that is an air treatment unit. The treated gas whose composition has been adjusted by the air treatment unit is supplied to the in-store space. 【0003】 This air composition regulating device executes an oxygen concentration 5% mode, an oxygen concentration 8 mode, an outside air introduction mode, and a breathing mode. The oxygen concentration 5 mode and the oxygen concentration 8% mode are modes in which the treated gas adjusted to a low oxygen concentration by the air treatment unit is supplied to the in-store space. The outside air introduction mode is a mode in which outside air is supplied to the in-store space. The breathing mode is a mode in which the air pump is stopped, and the oxygen concentration of the air in the store is decreased and the carbon dioxide concentration is increased by the respiration of goods (fruits and vegetables, flowers, etc.). 【Prior Art Documents】 【Patent Documents】 【0004】 【Patent Document 1】 Japanese Unexamined Patent Application Publication No. 2023-58951 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0005】 In the air composition regulating device, the composition of the air in the store is made to approach the set value by switching between the above-described plurality of modes. However, by switching each mode, the composition of the in-store space, specifically, the oxygen concentration and carbon dioxide concentration, changes greatly. As a result, the quality of fruits and vegetables and flowers may be impaired. 【0006】 The purpose of this disclosure is to provide an air composition adjustment device that can reduce the range of change in the composition of the air inside the chamber. [Means for solving the problem] 【0007】 The first embodiment relates to an air composition adjustment device. The air composition adjustment device includes a supply passage (S) that connects the external space (6) and the internal space (5) inside the storage compartment (2), an air processing unit (95) provided in the supply passage (S) that adjusts the composition of the air, air conveying units (231, 291) that convey the processed gas whose composition has been adjusted by the air processing unit (95) to the internal space (5) as first air via the supply passage (S), and a controller (110) that controls the air processing unit (95) and the air conveying units (231, 291). The controller (110) performs flow rate control during the operation of the air conveying units (231, 291) to adjust the flow rate of the first air to at least a set value so that the concentration of components in the internal air reaches a set value. 【0008】 In the first embodiment, when the air conveying unit (231, 291) is in operation, the controller (110) adjusts the flow rate of the first air processed by the air processing unit (95) so that the concentration of components in the air inside the chamber becomes a set value. If the flow rate of the first air changes, the supply rate of components supplied to the space inside the chamber changes, so that the concentration of components in the air inside the chamber can be brought closer to the set value. Therefore, it is possible to suppress changes in the composition of the air inside the chamber that occur when switching modes. 【0009】 In the second embodiment, in the first embodiment, the controller (110) performs a concentration control mode in which it supplies first air from the supply path (S) to the storage space (5) in response to an operation command. The controller (110) performs flow rate control during the concentration control mode. The controller (110) performs flow rate control during the concentration control mode. 【0010】 In the second embodiment, in one concentration control mode, the concentration of components in the internal air is adjusted to a set value by flow rate control. Therefore, it is possible to suppress large changes in the composition of the internal air that occur when switching modes. 【0011】 In a third embodiment, in the first or second embodiment, the air transport unit includes a variable flow rate pump (231, 291). The controller (110) adjusts the flow rate of the first air by controlling the pump (231, 291) in flow rate control. 【0012】 In the third embodiment, the flow rate of the first air is adjusted by controlling the pumps (231, 291) so that the concentration of the components in the air inside the chamber reaches a set value. 【0013】 A fourth embodiment further comprises an outside air introduction unit (40) that, in the first or second embodiment, introduces outside air from the outside space (6) into the inside space (5) as second air without going through the supply path (S). In flow rate control, the controller (110) adjusts the flow rate of the first air and the flow rate of the second air so that the concentration of components in the inside air reaches a set value. 【0014】 In the fourth embodiment, in addition to the flow rate of the first air, the flow rate of the second air supplied to the interior space (5) by the outside air inlet (40) is controlled so that the concentration of components in the interior air reaches a set value. 【0015】 A fifth aspect, in the fourth aspect, includes a ventilation device (40) that supplies outside air into the interior space (5) of the storage unit, in which the outside air intake (40) is provided. 【0016】 In the fifth embodiment, in addition to the flow rate of the first air, the flow rate of the second air supplied to the interior space (5) by the ventilation device (40) is controlled so that the concentration of components in the interior air reaches a set value. 【0017】 The sixth embodiment is one of the first to fifth embodiments, in which the controller (110) performs concentration control to adjust the concentration of the components of the first air so that the concentration of the components in the air inside the chamber reaches a set value while the air conveying unit (231, 291) is in operation. 【0018】 In the sixth embodiment, when the air conveying unit (231, 291) is in operation, the controller (110) adjusts the concentration of the components in the first air processed by the air processing unit (95) so that the concentration of the components in the air inside the chamber becomes a set value. If the concentration of the components in the first air changes, the supply rate of the components supplied to the space inside the chamber changes, so that the concentration of the components in the air inside the chamber can be brought closer to the set value. Therefore, it is possible to suppress large changes in the composition of the air inside the chamber that occur when switching modes. 【0019】 The seventh aspect is the sixth aspect, wherein the air processing unit (95) includes two adsorption units (234, 235) that perform an adsorption operation to adsorb components in the air and a desorption operation to desorb the adsorbed components. The air composition adjustment device further includes a first flow path (244, 275) through which a processed gas whose composition has been adjusted by the adsorption units (234, 235) flows, a second flow path (281) for discharging the processed gas from the first flow path (244, 275) to the outside of the chamber, and an on-off valve (272) provided in the second flow path (281). The controller (110) adjusts the concentration of the components of the first air by controlling the timing of opening and closing the on-off valve (272) in concentration control. 【0020】 In the seventh embodiment, the concentration of the components in the first air is adjusted by controlling the timing of opening and closing the on-off valve (272). This is because the concentration of the components in the processed gas flowing from the adsorption section (234, 235) to the first flow path (244, 275) changes, for example, during the desorption operation. If the on-off valve (272) is opened at a time when the concentration of the components in the processed gas is high, the high-concentration processed gas is discharged into the space outside the chamber (6). As a result, the concentration of the components in the first air supplied to the space inside the chamber (5) can be adjusted to be low. If the on-off valve (272) is opened at a time when the concentration of the components in the processed gas is low, the low-concentration processed gas is discharged into the space outside the chamber (6). As a result, the concentration of the components in the first air supplied to the space inside the chamber (5) can be adjusted to be high. 【0021】 In the eighth aspect, in the sixth aspect, the air treatment unit (95) includes two adsorption units (234, 235) that perform an adsorption operation of adsorbing components in the air and a desorption operation of desorbing the adsorbed components. The air treatment apparatus further includes a first flow path (244, 275) through which the processed gas whose composition is adjusted by the adsorption unit (234, 235) flows, a third flow path (255) that introduces the outside-air in the outside-air space (6) into the first flow path (244, 275) by bypassing the air treatment unit (95), and a flow rate adjustment valve (256) that adjusts the flow rate of the outside-air flowing from the third flow path (255) into the first flow path (244, 275). In concentration control, the controller (110) adjusts the concentration of the components of the first air by controlling the flow rate adjustment valve (256). 【0022】 In the eighth aspect, by opening the flow rate adjustment valve (256) to a predetermined opening degree, the processed gas after the composition is adjusted by the air treatment unit (95) and the outside-air flowing through the second flow path (281) by bypassing the air treatment unit (95) are mixed in the first flow path (244, 275). By adjusting the opening degree of the flow rate adjustment valve (256), the mixing ratio of the two gases changes, so the concentration of the components of the first air can be adjusted. 【0023】 In the ninth aspect, in any one of the first to eighth aspects, the controller (110) obtains a target flow rate for setting the carbon dioxide concentration in the indoor air to a set value. In flow rate control, the controller (110) adjusts the flow rate of the first air to the target flow rate. 【0024】 In the ninth aspect, by adjusting the flow rate of the first air to the target flow rate, the carbon dioxide concentration in the indoor air becomes the set value. Here, since the carbon dioxide concentration in the first air is relatively low, the target flow rate can be obtained by ignoring the carbon dioxide concentration contained in the first air. 【0025】 In the tenth aspect, in the ninth aspect, the controller (110) estimates the carbon dioxide generation rate of the fruits or flowers in the indoor space (5). The controller (110) obtains the target flow rate based on the estimated carbon dioxide generation rate. 【0026】 In the tenth aspect, based on the carbon dioxide generation rate of fresh produce or flowers, a target flow rate for the carbon dioxide concentration in the storage air to reach the set value is determined. This is because the carbon dioxide concentration in the storage air is affected by the carbon dioxide generation rate of the goods. As a result, the carbon dioxide concentration in the storage air can be quickly brought close to the set value. 【0027】 In the eleventh aspect, in the tenth aspect, the controller (110) estimates the carbon dioxide generation rate based on the actual volume of the storage space (5) and the carbon dioxide concentration in the storage air. Here, the "actual volume" means the volume of the substantial space in the storage space, in other words, the actual volume of the storage air existing in the storage space. 【0028】 In the eleventh aspect, based on the actual volume (Vs) of the storage space (5) and the carbon dioxide concentration in the storage air, the carbon dioxide generation rate of fresh produce or flowers is estimated. The carbon dioxide concentration in the storage air is affected by the actual volume of the storage space (5) and the carbon dioxide generation rate. Therefore, by using the actual volume and the carbon dioxide concentration in the storage air, the carbon dioxide generation rate can be accurately estimated. 【0029】 In the twelfth aspect, in any one of the sixth to eighth aspects, the controller (110) determines a target concentration for setting the oxygen concentration in the storage air to the set value. In the concentration control, the controller (110) adjusts the oxygen concentration of the first air to the target concentration. 【0030】 In the twelfth aspect, by adjusting the oxygen concentration of the first air to the target concentration, the oxygen concentration in the storage air reaches the set value. 【0031】 In the thirteenth aspect, in the twelfth aspect, the controller (110) estimates the oxygen consumption rate of fresh produce or flowers in the storage space (5). The controller (110) determines the target concentration based on the oxygen consumption rate. 【0032】 In the 13th embodiment, the target oxygen concentration required for the oxygen concentration in the warehouse air to reach a set value is determined based on the oxygen consumption rate of fruits, vegetables, or flowers. This is because the oxygen concentration in the warehouse air is affected by the oxygen consumption rate of the cargo. This allows the oxygen concentration in the warehouse air to quickly approach the set value. 【0033】 In the 14th aspect, in the 13th aspect, the controller (110) estimates the oxygen consumption rate based on the actual volume of the interior space (5) and the oxygen concentration in the air inside the interior. 【0034】 In the 14th embodiment, the oxygen consumption rate of fruits, vegetables, or flowers is estimated based on the actual volume of the storage space (5) and the oxygen concentration in the air inside the storage space. The oxygen concentration in the air inside the storage space is affected by the actual volume of the storage space (5) and the oxygen consumption rate. Therefore, by using the actual volume and the oxygen concentration in the air inside the storage space, the oxygen consumption rate can be estimated with high accuracy. 【0035】 In the 15th aspect, in the 11th or 14th aspect, the air composition adjustment device (90) further comprises a pressure adjustment unit (231) for changing the pressure in the internal space (5) and a pressure detection unit (170) for detecting the internal pressure in the internal space (5). The controller (110) estimates the actual volume based on a first index indicating the rate of change of the internal pressure when the internal pressure changes. 【0036】 In the 15th embodiment, the pressure adjustment unit (231) changes the internal pressure (Pi). When cargo is loaded into the internal space (5) and the actual volume of the internal space (5) changes, the rate of change of the internal pressure (Pi) changes. Specifically, if the actual volume (Vs) increases, the rate of increase or decrease of the internal pressure (Pi) slows down, and if the actual volume (Vs) decreases, the rate of increase or decrease of the internal pressure (Pi) speeds up. Therefore, the controller (110) estimates the actual volume of the internal space (5) based on a first index that indicates the rate of change of the internal pressure (Pi). 【0037】 The sixteenth aspect is that, in the first to fifteenth aspects, the air composition adjustment device further comprises concentration sensors (161, 162) for detecting the carbon dioxide concentration or oxygen concentration in the air inside the chamber. The controller (110) adjusts the flow rate of the first air in flow rate control so that the concentration detected by the concentration sensors (161, 162) reaches a set value. 【0038】 In the 16th embodiment, the flow rate of the first air is adjusted in the flow control so that the concentration detected by the concentration sensors (161, 162) reaches a set value. As a result, the carbon dioxide concentration and oxygen concentration in the air inside the chamber can be brought closer to the set value with high accuracy. 【0039】 The 17th aspect is that, in the 6th to 8th aspects, the air composition control device further comprises concentration sensors (161, 162) for detecting the carbon dioxide concentration or oxygen concentration in the air inside the chamber. The controller (110) adjusts the concentration of the first air in concentration control so that the concentration detected by the concentration sensors (161, 162) becomes a set value. 【0040】 In the 17th embodiment, in concentration control, the concentrations of the components of the first air are adjusted so that the concentrations detected by the concentration sensors (161, 162) reach the set values. This allows the carbon dioxide concentration and oxygen concentration in the air inside the chamber to be brought closer to the set values ​​with high accuracy. 【0041】 The 18th embodiment is an air composition adjustment device in any one embodiment of the 1st to 17th embodiments, further comprising a carbon dioxide sensor (162) for detecting the carbon dioxide concentration in the air inside the chamber. The controller (110) is configured to determine a target flow rate for setting the carbon dioxide concentration of the air inside the chamber to a set value. The controller (110) performs a first flow rate control, which adjusts the flow rate of the first air to a target flow rate, and a second flow rate control, which adjusts the flow rate of the first air so that the concentration detected by the carbon dioxide sensor (162) becomes a set value. 【0042】 In the 18th embodiment, in the first flow rate control, the flow rate of the first air is adjusted to a target flow rate that satisfies a set value. This allows the carbon dioxide concentration of the air inside the chamber to quickly approach the set value. In the second flow rate control, the flow rate of the first air is adjusted so that the concentration detected by the carbon dioxide concentration sensors (161, 162) becomes a set value. This allows the carbon dioxide concentration of the air inside the chamber to approach the set value with high accuracy. 【0043】 The 19th aspect is, in the 18th aspect, the controller (110) executes a first flow rate control when the first condition indicating that the carbon dioxide concentration in the air inside the chamber is close to a set value is not met. The controller (110) executes a second flow rate control when the first condition is met. 【0044】 In the 19th embodiment, if the first condition indicating that the carbon dioxide concentration in the air inside the storage chamber is close to the set value is not met, in other words, if the carbon dioxide concentration in the air inside the storage chamber is far from the set value, the controller (110) executes the first flow rate control. As a result, the carbon dioxide concentration can be quickly brought closer to the set value. If the first condition indicating that the carbon dioxide concentration in the air inside the storage chamber is close to the set value is met, the controller (110) executes the second flow rate control. As a result, the carbon dioxide concentration in the air inside the storage chamber can be brought even closer to the set value with greater accuracy. 【0045】 The 20th embodiment includes an oxygen sensor (161) for detecting the oxygen concentration in the air inside the chamber, in any one of the sixth to eighth embodiments. The controller (110) is configured to determine a target concentration for setting the oxygen concentration of the air inside the chamber to a set value. The controller (110) performs a first concentration control, which is a concentration control that adjusts the oxygen concentration of the first air to a target concentration, and a second concentration control, which is a concentration control that adjusts the oxygen concentration of the first air so that the detected concentrations of the oxygen concentration sensors (161, 162) reach a set value. 【0046】 In the 20th embodiment, in the first concentration control, the oxygen concentration of the first air is adjusted to a target concentration that satisfies the set value. This allows the oxygen concentration of the air inside the chamber to quickly approach the set value. In the second concentration control, the oxygen concentration of the first air is adjusted so that the concentration detected by the oxygen concentration sensors (161, 162) becomes the set value. This allows the oxygen concentration of the air inside the chamber to approach the set value with high accuracy. 【0047】 The 21st aspect is, in the 20th aspect, the controller (110) executes the first concentration control when the second condition, which indicates that the oxygen concentration in the air inside the chamber is close to a set value, is not met. The controller (110) executes the second concentration control when the second condition is met. 【0048】 In the 21st embodiment, if the second condition indicating that the oxygen concentration in the air inside the storage chamber is close to the set value is not met, in other words, if the oxygen concentration in the air inside the storage chamber is far from the set value, the controller (110) executes the first concentration control. As a result, the oxygen concentration can be quickly brought closer to the set value. If the second condition indicating that the oxygen concentration in the air inside the storage chamber is close to the set value is met, the controller (110) executes the second concentration control. As a result, the oxygen concentration in the air inside the storage chamber can be brought even closer to the set value with greater accuracy. 【0049】 The 22nd embodiment is a transport container comprising an air composition adjustment device (90) according to any one of claims 1 to 21. [Brief explanation of the drawing] 【0050】 [Figure 1] Figure 1 is a schematic perspective view of a transport refrigeration system according to an embodiment. [Figure 2] Figure 2 is a cross-sectional view of a transport container equipped with a transport refrigeration device according to an embodiment. [Figure 3] Figure 3 is a piping diagram showing the refrigerant circuit of the transport refrigeration system of the embodiment. [Figure 4]Figure 4 is a schematic front view of the ventilation system. Figure 4(A) shows the lid in the closed position, Figure 4(B) shows the lid in the intermediate position, and Figure 4(C) shows the lid in the fully open position. [Figure 5] Figure 5 is a piping diagram showing the configuration of the air composition adjustment device according to the embodiment. [Figure 6] Figure 6 is a diagram corresponding to Figure 5, showing the air composition adjustment device that performs the first operation of the gas supply operation. [Figure 7] Figure 7 is a diagram corresponding to Figure 5, showing the air composition adjustment device that performs the second operation of the gas supply operation. [Figure 8] Figure 8 corresponds to Figure 5, which shows an air composition adjustment device that performs outside air intake. [Figure 9] Figure 9 is a block diagram showing the configuration of the controller included in the air composition adjustment device of the embodiment. [Figure 10] Figure 10 is a table showing the timing of operation in the 8% oxygen concentration mode. [Figure 11] Figure 11 is a table showing the timing of operation in the 5% oxygen concentration mode. [Figure 12] Figure 12 is a basic flowchart of the preliminary steps. [Figure 13] Figure 13 shows a flowchart, timing chart, and formulas to explain the first airtightness measurement mode. [Figure 14] Figure 14 shows a flowchart, timing chart, and formulas to explain the second airtightness measurement mode. [Figure 15] Figure 15 shows a flowchart, timing chart, and formulas to explain the third airtightness measurement mode. [Figure 16] Figure 16 shows a flowchart, timing chart, and formulas to explain the first estimated operation. [Figure 17] Figure 17 shows a flowchart, timing chart, and formulas to explain the second estimated operation. [Figure 18]Figure 18 is a table showing the relationship between the operating modes of the air composition control device and the first estimated operation and the second estimated operation. [Figure 19] Figure 19 is a flowchart of the first respiratory volume estimation process. [Figure 20] Figure 20 is a flowchart of the second respiratory volume estimation process. [Figure 21] Figure 21 is a basic flowchart of the concentration adjustment mode. [Figure 22] Figure 22 is a flowchart of the flow rate control process. [Figure 23] Figure 23 is a flowchart of the concentration control process. [Figure 24] Figure 24 is a timing chart showing the changes in oxygen concentration of the processed gas during the first and second operations, and an example of control of the gas discharge valve and gas supply valve. [Figure 25] Figure 25 is a diagram corresponding to Figure 5 of the transport container in Modification Example 1. [Figure 26] Figure 26 is a diagram corresponding to Figure 5 of the transport container for modified example 3, in which concentration control is performed. [Modes for carrying out the invention] 【0051】 The embodiments of this disclosure will be described below with reference to the drawings. In the following description, the terms "front," "back," "up," "down," "right," and "left" refer to the directions indicated by the arrows in Figure 1. 【0052】 (1) Overview This disclosure relates to a transport container (1). This transport container (1) is a reefer container capable of controlling the internal temperature. This transport container (1) is used for transporting perishable goods (e.g., fruits, vegetables, flowers, etc.) that respire by taking in oxygen (O2) from the air and releasing carbon dioxide (CO2). 【0053】 As shown in Figures 1 and 2, the transport container (1) comprises a container body (2) and a transport refrigeration unit (10). The transport refrigeration unit (10) is attached to the container body (2). The transport container (1) is used for maritime transport. The transport container (1) is transported by a maritime transport vehicle such as a ship. 【0054】 The container body (2) is a storage unit for the fresh produce mentioned above. 【0055】 The container body (2) is formed in the shape of a hollow box. The container body (2) is formed in a horizontal shape. An opening is formed at one end of the container body (2) in the longitudinal direction. The opening of the container body (2) is closed by a transport refrigeration device (10). Inside the container body (2), an interior space (5) is formed for storing perishable goods. 【0056】 A floor plate (3) for loading cargo is placed at the bottom of the interior space (5). Between this floor plate (3) and the bottom plate of the container body (2), an underfloor passage (4) is formed for the air blown out by the transport refrigeration unit (10) to flow. The underfloor passage (4) is a passage that extends along the bottom plate of the container body (2) in the longitudinal direction of the container body (2). One end of the underfloor passage (4) is connected to the outlet (27) of the transport refrigeration unit (10), and the other end communicates with the space above the floor plate (3) (i.e., the space where the cargo is stored). 【0057】 (2) Basic configuration of transport refrigeration equipment The transport refrigeration unit (10) comprises a casing (20), a refrigerant circuit (11) that performs the refrigeration cycle, an external fan (34), and an internal fan (35). 【0058】 (2-1) Casing The casing (20) comprises an outer wall section (21), an inner wall section (22), a back panel (24), and a partition panel (25). As will be described later, the casing (20) is equipped with a refrigerant circuit (11), an outer fan (34), and an inner fan (35). 【0059】 The outer wall portion (21) is a plate-shaped member positioned to cover the open end of the container body (2). The lower part of the outer wall portion (21) bulges inward into the container body (2). The inner wall portion (22) is a plate-shaped member that follows the shape of the outer wall portion (21). The inner wall portion (22) is positioned to cover the inner surface of the outer wall portion (21) of the container body (2). The space between the outer wall portion (21) and the inner wall portion (22) is filled with insulation material (23). 【0060】 The casing (20) has a shape in which its lower part is recessed inward into the container body (2). The lower part of the casing (20) forms an external equipment room (28) that communicates with the external space of the transport container (1). An external fan (34) is located in this external equipment room (28). 【0061】 The back panel (24) is a generally rectangular, flat member. The back panel (24) is positioned inside the container body (2) relative to the interior wall (22), and forms an internal air passage (29) between the back panel (24) and the interior wall (22). The upper end of this internal air passage (29) constitutes the intake port (26) of the casing (20), and the lower end constitutes the outlet port (27) of the casing (20). 【0062】 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 internal 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). 【0063】 (2-2) 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 secondary flow path (29b) of the internal air flow path (29). The compressor (12) is located in the external equipment room (28). 【0064】 (2-3) Operation of transport refrigeration equipment The transport refrigeration unit (10) performs a cooling operation to cool the air inside the transport container (1). 【0065】 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. 【0066】 During cooling operation, the external fan (34) and the internal fan (35) operate. When the external fan (34) operates, 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) operates, the internal air from the internal 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. 【0067】 Let's explain the airflow inside the storage unit. The air present in the storage unit space (5) flows through the intake port (26) into the primary flow path (29a) of the storage unit airflow path (29), and is blown out into the secondary flow path (29b) by the storage unit fan (35). The air that flows into the secondary flow path (29b) is cooled as it passes through the storage unit heat exchanger (15), and is then blown out from the outlet (27) into the underfloor flow path (4), and flows back into the storage unit space (5) through the underfloor flow path (4). 【0068】 In the internal air passage (29), the primary passage (29a) is located on the intake side of the internal fan (35), and the secondary passage (29b) is located on the outlet side of the internal fan (35). Therefore, when the internal fan (35) is operating, the air pressure in the secondary passage (29b) is slightly higher than the air pressure in the primary passage (29a). 【0069】 (3) Ventilation system The transport refrigeration unit (10) is equipped with a ventilation unit (40). The ventilation unit (40) ventilates the interior space (5) of the container body (2). The ventilation unit (40) has an air supply function that supplies outside air to the interior space (5) and an exhaust function that discharges the interior air to the outside space (6). 【0070】 (3-1) Configuration of the ventilation system As shown in Figure 1, the ventilation device (40) is located in the upper left part of the casing (20) of the transport refrigeration device (10). As shown in Figure 2, the ventilation device (40) is installed in a ventilation opening (38) formed in the casing (20). The ventilation opening (38) penetrates the casing (20) in the front-to-back direction. 【0071】 As shown in Figure 2, an air supply passage (41) and an exhaust passage (42) are formed inside the ventilation device (40). The air supply passage (41) and the exhaust passage (42) connect the interior space (5) and the exterior space (6). 【0072】 Specifically, the air supply passage (41) connects the primary air passage (29a) of the internal air passage (29) to the external space (6). The end of the air supply passage (41) on the external space (6) side is the air supply port (41a). The air supply port (41a) is an air inlet that connects the external space (6) to the inside of the container body (2). The exhaust passage (42) connects the secondary air passage (29b) of the internal air passage (29) to the external space (6). The end of the exhaust passage (42) on the external space (6) side is the exhaust port (42a). The air supply port (41a) and the exhaust port (42a) are somewhat elongated openings that extend in the circumferential direction. 【0073】 The ventilation device (40) includes an opening / closing cover (45). The opening / closing cover (45) is a disc-shaped member. The opening / closing cover (45) is provided to cover the air supply port (41a) and the exhaust port (42a). The opening / closing cover (45) is driven by a motor (not shown) and is rotatable around its central axis. 【0074】 As shown in Figure 4, the opening / closing lid (45) has an air intake opening (46) and an exhaust opening (47). Each of the air intake opening (46) and the exhaust opening (47) penetrates the opening / closing lid (45) in the thickness direction. The shape of the air intake opening (46) is the same as the shape of the air intake port (41a). The shape of the exhaust opening (47) is the same as the shape of the exhaust port (42a). In the opening / closing lid (45), the air intake opening (46) and the exhaust opening (47) are formed in such a position that when the entire air intake opening (46) overlaps with the air intake port (41a), the entire exhaust opening (47) overlaps with the exhaust port (42a). 【0075】 (3-2) Operation of the ventilation system The ventilation device (40) is configured to adjust the flow rate of outside air supplied to the interior space (5) (supply air flow rate) and the flow rate of inside air discharged from the interior space (5) (exhaust air flow rate) by rotating the opening and closing lid (45). 【0076】 Specifically, when the opening / closing lid (45) is rotated, the area of ​​the portion of the air supply port (41a) that overlaps with the air supply opening (46) and the area of ​​the portion of the exhaust port (42a) that overlaps with the exhaust opening (47) change. Outside air flows into the air supply passage (41) through the portion of the air supply port (41a) that overlaps with the air supply opening (46), and then flows into the interior space (5). Inside air flowing through the exhaust passage (42) flows out into the exterior space (6) through the portion of the exhaust port (42a) that overlaps with the exhaust opening (47). 【0077】 Increasing the area of ​​the portion of the air supply port (41a) that overlaps with the air supply opening (46) increases the air supply flow rate, while decreasing the area of ​​that portion decreases the air supply flow rate. Increasing the area of ​​the portion of the exhaust port (42a) that overlaps with the exhaust opening (47) increases the exhaust flow rate, while decreasing the area of ​​that portion decreases the exhaust flow rate. 【0078】 When the opening / closing cover (45) is in the position shown in Figure 4(A), the entire air supply port (41a) is covered by the opening / closing cover (45), and the entire exhaust port (42a) is also covered by the opening / closing cover (45). As a result, the area of ​​the portion of the air supply port (41a) that overlaps with the air supply opening (46) and the area of ​​the portion of the exhaust port (42a) that overlaps with the exhaust opening (47) become zero. In other words, the air supply passage (41) and the exhaust passage (42) become completely closed. Therefore, in this state, both the air supply flow rate and the exhaust flow rate become zero. 【0079】 When the opening / closing cover (45) is in the position shown in Figure 4(C), the entire air intake port (41a) overlaps with the air intake opening (46), and the entire exhaust port (42a) overlaps with the exhaust opening (47). Therefore, the area of ​​the portion of the air intake port (41a) that overlaps with the air intake opening (46) (the dotted portion in Figure 4(C)) and the area of ​​the portion of the exhaust port (42a) that overlaps with the exhaust opening (47) (the dotted portion in Figure 4(C)) are both maximized. In other words, the air intake passage (41) and the exhaust passage (42) are fully open. Consequently, in this state, both the air intake flow rate and the exhaust flow rate reach their maximum flow rates. 【0080】 When the opening / closing cover (45) is in the position shown in Figure 4(B), a portion of the air intake port (41a) overlaps with the air intake opening (46), and a portion of the exhaust port (42a) overlaps with the exhaust opening (47). As a result, the area of ​​the portion of the air intake port (41a) that overlaps with the air intake opening (46) (the dotted portion in Figure 4(B)) and the area of ​​the portion of the exhaust port (42a) that overlaps with the exhaust opening (47) (the dotted portion in Figure 4(B)) are both intermediate areas smaller than the maximum. Therefore, in this state, both the air intake flow rate and the exhaust flow rate are intermediate flow rates that are greater than zero and less than the maximum flow rate. 【0081】 (4) Air composition adjustment device The air composition adjustment device (100) processes the ambient air outside the container to generate a treated gas with a different composition from the outside air. The air composition adjustment device (100) supplies the generated treated gas to the interior space (5) of the container body (2). 【0082】 (4-1) Basic configuration of an air composition control device The air composition control device (100) is installed in the transport refrigeration unit (10) to perform so-called CA (Controlled Atmosphere) transport. The air composition control device (100) adjusts the air composition in the interior space (5) of the transport container (1). 【0083】 As shown in Figure 5, the air composition adjustment 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 air composition adjustment device (100) is a so-called PSA (Pressure Swing Adsorption) type gas separation device. 【0084】 The air composition adjustment device (100) generates the gas to be treated by processing the outside air, which is the ambient air. Specifically, the air composition adjustment device (100) separates the outside air into a nitrogen-enriched gas, which has a higher nitrogen concentration and a lower oxygen concentration than the outside air, and an oxygen-enriched gas, which has a lower nitrogen concentration and a higher oxygen concentration than the outside air. 【0085】 The air composition adjustment device (90) includes a supply passage (S) that connects the external space (6) and the internal space (5) inside the container body (2), which is a storage compartment; an air processing unit (95) that adjusts the composition of the external air; and an air pump (231) that transports the air in the supply passage (S) to the internal space (5) as first air. The supply passage (S) is composed of multiple pipes that connect the external space (6) and the internal space (5). The multiple pipes include an external air pipe (241), an inlet pipe (242), a first gas pipe (244), a bypass connecting pipe (255), and a gas supply pipe (275). The air pump (231) is an example of an air transport unit. The first gas pipe (244) and the gas supply pipe (275) are examples of a first flow path. 【0086】 (4-2) Filter unit, outside air pipe The filter unit (220) is a box-shaped component. The filter unit (220) is installed in the external 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. 【0087】 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). 【0088】 (4-3) 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). 【0089】 (4-4) 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). 【0090】 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). 【0091】 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). 【0092】 The air pump (231) in this embodiment is of variable flow rate. Specifically, the air pump (231) is configured so that the rotational speed of the motor that rotates the pump body can be changed. The motor is an inverter type with adjustable operating frequency, but it may also be a geared motor with multi-stage rotational speed adjustment. 【0093】 (4-5) Introduction 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). 【0094】 (4-6) Suction tube 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). 【0095】 (4-7) First gas pipe The first gas pipe (244) is the piping through which nitrogen-enriched gas discharged from the pressure-reducing pump (231b) 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). 【0096】 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. 【0097】 (4-8) Switching valve 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. 【0098】 The first switching valve (232) has its first port connected to one end of the first suction cylinder (234). The first switching valve (232) 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 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). 【0099】 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). 【0100】 (4-9) Adsorption cylinder Each of the first adsorption cylinder (234) and the second adsorption cylinder (235) is an adsorption unit comprising a cylindrical container with both ends closed and an adsorbent filled in the container. The adsorption cylinders (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. 【0101】 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 a pressurized state where the pressure is higher than atmospheric pressure, and desorbing nitrogen and water under a reduced pressure state 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). 【0102】 The first suction cylinder (234) and the second suction cylinder (235), together with the first switching valve (232) and the second switching valve (233), constitute an air processing unit (95). 【0103】 (4-10) 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 the first passage through which oxygen-enriched gas flows. The first branch pipe (247a) is a pipe connecting 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 connecting 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. 【0104】 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 of the main pipe (246) to the other, and blocks air to flow in the reverse direction. 【0105】 (4-11) 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 suction 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 suction cylinder (235) and the check valve (261) in the second branch pipe (247b). 【0106】 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). 【0107】 (4-12) Exhaust connection pipe An exhaust connecting pipe (271) is connected to the first gas pipe (244). The exhaust connecting pipe (271) is an example of a second flow path. One end of the exhaust connecting 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 connecting 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 connecting pipe (271) is connected to one end of the gas discharge pipe (276). 【0108】 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). 【0109】 (4-13) 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). 【0110】 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. 【0111】 (4-14) 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 into 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). 【0112】 (4-15) Measurement piping A measuring pipe (281) is connected to the first gas pipe (244). The measuring pipe (281) is the pipe that connects the first gas pipe (244) to the sensor unit (160). One end of the measuring pipe (281) is connected to the downstream side of the check valve (264) in the first gas pipe (244). The other end of the measuring pipe (281) is connected to the sensor unit (160). 【0113】 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). 【0114】 (4-16) 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 interior space (5) of the transport container (1). The bypass connecting pipe (255) is an example of a third flow path. 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). 【0115】 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 inside space (5) of the storage unit without changing its composition. 【0116】 (4-17) 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). 【0117】 The oxygen sensor (161) is a zirconia current type concentration sensor that measures the oxygen concentration of a mixed gas such as air. The carbon dioxide sensor (162) is a non-dispersive infrared (NDIR) type concentration sensor that measures the carbon dioxide concentration of a mixed gas such as air. The oxygen sensor (161) and the carbon dioxide sensor (162) are housed in a sensor case (163). 【0118】 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). 【0119】 A measuring pipe (281) is connected to the sensor case (163). An outlet pipe (165) is 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). The outlet end of the outlet pipe (165) opens into the primary passage (29a) of the internal air passage (29). 【0120】 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. 【0121】 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 flows 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 flows from the measuring pipe (281) into the sensor case (163). 【0122】 (4-18) 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. 【0123】 (4-19) Differential pressure sensor and internal temperature sensor The air composition adjustment device (100) has a differential pressure sensor (170) as a pressure detection unit. The differential pressure sensor (170) is used to detect the pressure in the internal space (5). The differential pressure sensor (170) detects the differential pressure (ΔP) between the internal pressure (Pi) in the internal space (5) and the external pressure (Po) in the external space (6). As shown in Figures 2 and 5, the differential pressure sensor (170) is placed in the internal space (5). Specifically, the differential pressure sensor (170) is placed in the primary flow path (29a) of the internal air flow path (29). The differential pressure sensor (170) comprises a main body case (171), a sensor unit (172) located inside the main body case (171), an internal communication passage (173) connecting the inside of the main body case (171) to the internal storage space (5), and an external communication passage (174) connecting the inside of the main body case (171) to the external storage space (6). 【0124】 The internal communication passage (173) is composed of a communication hole formed in the main body case (171). In this embodiment, the internal communication passage (173) opens toward the primary flow path (29a). More specifically, the internal communication passage (173) opens toward the primary flow path (29a) so as to face away from the intake side of the internal fan (35). This suppresses the influence of the dynamic pressure of the internal air flowing through the internal air passage (29) on the detection value of the differential pressure sensor (170). The external communication passage (174) is formed inside the tube. The tube extends from the main body case (171) to the external space (6). The differential pressure sensor (170) detects the differential pressure ΔP between the internal space (5) and the external space (6). 【0125】 The air composition adjustment device (100) has an internal temperature sensor (51). The internal temperature sensor (51) detects the temperature of the air inside the chamber. The internal temperature sensor (51) is positioned in the primary flow path (29a) of the internal air flow path (29). 【0126】 (5) Operation of the air composition control device (5-1) Gas supply operation The air composition control device (100) performs a gas supply operation. The gas supply operation generates nitrogen-enriched gas by processing the outside air and supplies this nitrogen-enriched gas to the inside space (5). During the gas supply operation, the ventilation exhaust valve (151) is opened. 【0127】 During the gas supply operation, the air composition adjustment device (100) repeatedly performs the first operation and the second operation alternately. The air composition adjustment device (100) repeatedly performs the first operation and the second operation alternately for a predetermined switching time (for example, 14 seconds). As a result, in the air processing unit (95) of the air composition adjustment device (100), the outside air is separated into nitrogen-enriched gas and oxygen-enriched gas. 【0128】 (5-1-1) 1st action 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 adsorption operation is performed on the first adsorption cylinder (234) and a detachment operation is performed on the second adsorption cylinder (235). 【0129】 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). 【0130】 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 interior space (5) through the gas supply pipe (275). 【0131】 (5-1-2)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 adsorption operation targeting the second suction cylinder (235) are performed. 【0132】 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). 【0133】 Meanwhile, the depressurization 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 depressurization pump (231b). The depressurization 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 interior space (5) through the gas supply pipe (275). 【0134】 (5-2) Open air intake operation The air composition adjustment device (100) performs an outside air intake operation. The outside air intake operation is the operation of supplying outside air, which is the atmosphere, to the interior space (5) of the storage facility without changing its composition. 【0135】 As shown in Figure 8, during the outside air intake operation, both the first switching valve (232) and the second switching valve (233) are set to the second state. Also, during the outside air intake 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 intake operation, the air pump (231) is activated and the ventilation exhaust valve (151) is opened. 【0136】 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 the outside air intake operation, air with the same composition as the atmosphere is supplied to the internal space (5) of the transport container (1). 【0137】 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). 【0138】 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 intake 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. 【0139】 (6) Controller The air composition adjustment device (100) has a controller (110). As shown in Figure 9, 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. 【0140】 The controller (110) controls the components of the air composition control device (100). The controller (110) receives the measured values ​​from the oxygen sensor (161) and the carbon dioxide sensor (162). The controller (110) controls the air pump (231), the first switching valve (136), and the second switching valve (137). The controller (110) also controls the ventilation exhaust valve (151), the purge valve (251), the bypass valve (256), the gas discharge valve (272), the gas supply valve (273), and the measuring on / off valve (282). 【0141】 The controller (110) controls the ventilation device (40). Specifically, the controller (110) adjusts the opening of the supply air port (41a) and the exhaust air port (42a) by rotating the opening / closing cover (45) of the ventilation device (40). Changing the opening of the supply air port (41a) changes the flow rate of outside air supplied to the interior space (5) through the supply air passage (41). Changing the opening of the exhaust air port (42a) changes the flow rate of inside air discharged to the exterior space (6) through the exhaust passage (42). 【0142】 (7) Operating Mode The operating modes of the air composition control device (100) are described below. The controller (110) causes the air composition control device (100) to perform five operating modes. These operating modes include an 8% oxygen concentration mode, a 5% oxygen concentration mode, an outside air intake mode, a breathing mode, and a concentration control mode. 【0143】 The 8% oxygen concentration mode is an operating mode in which the air composition control device (100) supplies nitrogen-enriched gas with an average oxygen concentration of 8% to the interior space (5). The 5% oxygen concentration mode is an operating mode in which the air composition control device (100) supplies nitrogen-enriched gas with an average oxygen concentration of 5% to the interior space (5). The outside air introduction mode is an operating mode in which the air composition control device (100) supplies outside air directly to the interior space (5). The breathing mode is an operating mode in which the air composition control device (100) stops supplying nitrogen-enriched gas and outside air to the interior space (5) in order to change the composition of the air inside the storage unit due to the breathing of the cargo inside the unit. The concentration adjustment mode is an operating mode in which the oxygen concentration and carbon dioxide concentration in the interior space (5) are brought closer to the set values ​​without stopping the air pump (231). ) adjusts the air composition in the interior space (5) by switching between these operating modes. 【0144】 (7-1) Oxygen concentration 8% mode As shown in Figure 10, in the 8% oxygen concentration mode, the air composition adjuster (100) repeatedly performs the first and second operations alternately. Between the first and second operations, the air composition adjuster (100) performs a pressure equalization operation. During the pressure equalization operation, the controller (110) opens the purge valve (251). This quickly equalizes the internal pressures of the first adsorption cylinder (234) and the second adsorption cylinder (235). 【0145】 In the 8% oxygen concentration mode, the controller (110) keeps the gas discharge valve (272) closed and the gas supply valve (273) open at all times. As a result, low-oxygen gas is supplied to the interior space (5) from the start of the first and second operations. In each operation, the oxygen concentration in the nitrogen-enriched gas changes over time. Specifically, at the beginning of each operation, nitrogen-enriched gas with a relatively high oxygen concentration is generated because outside air remains in the adsorption cylinders (234, 235) and piping, and at the end of each operation, the pressure inside the adsorption cylinders (234, 235) decreases from the initial state, so more nitrogen components are desorbed, and nitrogen-enriched gas with a relatively high oxygen concentration is generated. In the 8% oxygen concentration mode, nitrogen-enriched gas is supplied to the interior space (5) from the start of the first and second operations, so the average oxygen concentration of the nitrogen-enriched gas over the entire duration of each operation is relatively high at 8%. 【0146】 (7-2) Oxygen concentration 5% mode As shown in Figure 11, in the 5% oxygen concentration mode, the air composition adjuster (100) repeatedly performs the first and second operations alternately, similar to the 8% oxygen concentration mode. Between the first and second operations, the air composition adjuster (100) performs a pressure equalization operation. 【0147】 In the 5% oxygen concentration mode, the controller (110) causes the air composition adjuster (100) to perform a gas discharge operation for a predetermined time (e.g., 4 seconds) from the start of the first operation. During the gas discharge operation, the controller (110) opens the gas discharge valve (272) and closes the gas supply valve (273). As described above, a nitrogen-enriched gas with a relatively high oxygen concentration is generated at the beginning of each operation. By performing the gas discharge operation, the nitrogen-enriched gas with a relatively high oxygen concentration is not supplied to the interior space (5) but is discharged to the exterior space (6) via the gas discharge pipe (276). Thereafter, for the remainder of each operation, the controller (110) closes the gas discharge valve (272) and opens the gas supply valve (273). Thus, in the 5% oxygen concentration mode, nitrogen-enriched gas is discharged into the space outside the chamber (6) from the start of the first or second operation until a predetermined time has elapsed. As a result, the average oxygen concentration of the nitrogen-enriched gas over the entire duration of each operation is relatively low at 5%. 【0148】 (7-3) Outdoor air intake mode In the outside air intake mode, outside air from the outside space (6) is supplied directly to the inside space (5). In the outside air intake mode, the controller (110) causes the air composition adjustment device (100) to perform the outside air intake operation described above. The oxygen concentration of the outside air is approximately 21%. The outside air intake mode can increase the oxygen concentration of the air inside the storage unit. 【0149】 (7-4) Breathing Modes In breathing mode, the controller (110) stops the air pump (231) and closes the gas discharge valve (272) and the measuring on / off valve (282). In breathing mode, nitrogen-enriched gas and outside air are not supplied to the interior space (5). As a result, the oxygen concentration in the interior air decreases and the carbon dioxide concentration increases as the cargo breathes. 【0150】 (7-5) Concentration adjustment mode (overview) In concentration adjustment mode, the controller (110) performs flow rate control and concentration control so that the oxygen concentration and carbon dioxide concentration in the air inside the chamber reach the set values. Here, the set values ​​include the oxygen concentration set value (SP_O2) and the carbon dioxide concentration set value (SP_CO2). The oxygen concentration set value (SP_O2) and the carbon dioxide concentration set value (SP_CO2) are input to the controller (110) by the user. That is, the user sets any set value to the controller (110) according to the type of produce and flowers to be loaded into the chamber space (5). Details of the concentration adjustment mode will be explained later. 【0151】 (8) Preparatory actions The air composition control device (90) of this embodiment performs preliminary operations to estimate the respiration rate of the cargo (fruits and vegetables and flowers) before the concentration control mode is executed. This is because the respiration rate of the cargo is greatly affected by the oxygen concentration and carbon dioxide in the storage space (5). As shown in Figure 12, the preliminary operations sequentially perform the measurement of the Cv value in step ST10, the estimation of the actual volume (Vs) in step ST11, and the estimation of the respiration rate in step ST12. 【0152】 (8-1) Measurement of Cv value The Cv value is an indicator of the airtightness of a transport container (1). A smaller Cv value indicates higher airtightness, making it less likely for the air inside the container (5) to leak into the outside space (6). A larger Cv value indicates higher airtightness, making it easier for the air inside the container (5) to leak into the outside space (6). For example, if the Cv value is 3.33 or less, the transport container (1) is relatively airtight, allowing the transport refrigeration unit (10) to sufficiently cool the air inside, and allowing the air composition adjustment device (100) to sufficiently adjust the composition of the air inside. For example, if the Cv value is greater than 3.33 and less than 4.12, the transport refrigeration unit (10) can sufficiently cool the air inside, but it becomes difficult to adjust the composition of the air inside using the air composition adjustment device (100). For example, if the Cv value is 4.12 or higher, it becomes difficult to cool the internal air by the transport refrigeration unit (10) and to adjust the composition of the internal air by the air composition adjustment unit (100). Thus, the Cv value is useful for evaluating the airtightness performance of the transport container (1). 【0153】 The controller (110) executes an airtightness measurement mode for measuring the Cv value of the transport container (1). The airtightness measurement mode of this embodiment includes a first airtightness measurement mode, a second airtightness measurement mode, and a third airtightness measurement mode. The first airtightness estimation mode is a mode that measures the Cv value using the depressurization method. The second airtightness estimation mode is a mode that measures the Cv value using the pressure boosting method. The third airtightness estimation mode is a mode that measures the Cv value using the constant pressure method. 【0154】 (8-1-1) First airtightness measurement mode (depressurization method) In the first airtightness measurement mode, the Cv value is automatically measured by the depressurization method. The controller (110) increases the internal pressure of the storage space (5) by operating the air pump (231) as a pressure regulating unit. The controller (110) then determines the Cv value based on the rate of decrease in the internal pressure. 【0155】 Specifically, as shown in Figure 13, in step ST11, the controller (110) operates the air pump (231) as a pressure regulating unit. In step ST11, the controller (110) closes the gas discharge valve (272), the measuring on / off valve (282), and the ventilation exhaust valve (151), and completely closes the supply air passage (41) and exhaust passage (42) of the ventilation device (40). In step ST11, the air composition adjustment device (100) opens the bypass valve (256) and the gas supply valve (273) in the same manner as the outside air introduction operation described above, and supplies outside air directly into the interior space (5) by the pressurizing pump (231a). However, as will be described in detail later, the air composition adjustment device (100) may close the bypass valve (256), open the gas supply valve (273), and supply the gas processed in the air processing unit (95) to the chamber space (5) by the pressure reducing pump (231b), similar to the gas supply operation described above. 【0156】 When air is introduced into the internal space (5), the internal pressure (Pi) increases in step ST12. In step ST13, the controller (110) stops the air pump (231) when the internal pressure (Pi) exceeds the first pressure (P1). The internal pressure (Pi) is determined by the differential pressure (ΔP) detected by the differential pressure sensor (170). The differential pressure (ΔP) is the difference between the internal pressure (Pi) and the external pressure (Po) (ΔP = Pi - Po). In this embodiment, the external pressure (Po) is set to atmospheric pressure (101.3 [kPa]). The controller (110) calculates the internal pressure (Pi) by adding the external pressure (Po) (atmospheric pressure) to the differential pressure (ΔP). 【0157】 In step ST14, the controller (110) measures the first time (Δt1) until the internal pressure (Pi) decreases from the first pressure (P1) to the second pressure (P2). In the first airtightness measurement mode, the first pressure (P1) is greater than the second pressure (P2). For example, the first pressure (P1) is set to 300 [kPa] and the second pressure (P2) is set to 100 [kPa]. As shown in Figure 13, the controller (110) measures the first time (Δt1) from the first time point (t1) when the internal pressure (Pi) is the first pressure (P1) to the second time point (t2) when the internal pressure (Pi) is the second pressure (P2). If the airtightness of the transport container (1) is low, the rate of decrease in internal pressure (Pi) increases, so the first time (Δt1) becomes shorter. If the airtightness of the transport container (1) is high, the rate of decrease in internal pressure (Pi) will be low, and the first time (Δt1) will be longer. Thus, the rate of decrease in internal pressure, or more precisely, the time it takes for the internal pressure to decrease to a predetermined pressure, serves as an indicator of the airtightness of the transport container (1). 【0158】 Next, in step ST15, the controller (110) obtains the internal pressure (Pi), external pressure (Po), differential pressure (ΔP), and internal air temperature (Tr) when the internal pressure (Pi) reaches the second pressure (P2). Next, in step ST16, the controller (110) calculates the Cv value based on equations (1), (2), and (3) in Figure 13. Here, Qo is the outflow rate of gas [m³] flowing out of the internal space (5) at the first time (Δt1). 3 Qi is the flow rate of gas flowing into the storage space (5) at the first time (Δt1) [m 3The formula is [ / h]. G is the specific gravity of the gas (air) (=1.0). Tr is the internal air temperature, i.e., the temperature detected by the internal temperature sensor (51). P1 is the internal pressure at the first time point (t1) (first pressure (P1)). P2 is the internal pressure at the second time point (t2) (second pressure (P2)). V1 is the volume of gas present in the internal space (5) at the first time point (t1). If no cargo is loaded into the internal space (5), V1 corresponds to the total volume when the internal space (5) is empty. V2 is the volume of gas in the internal space (5) at the second time point (t2). Δt1 is the first hour. Equation (1) is the basic formula for calculating the Cv value, equation (2) is a theoretical formula based on the equation of state in constant volume and isothermal change, and equation (3) is a theoretical formula for calculating V2. 【0159】 In the depressurization method, the air pump (231) is stopped at the first time (Δt1), so Qi becomes zero. Therefore, Qo can be determined based on equations (2) and (3). By substituting Qo and other parameters into equation (1), the Cv value can be obtained. The controller (110) may determine the Cv value using a function that includes these equations, or it may determine the Cv value based on a data table that includes these relationships. 【0160】 (8-1-2) Second airtightness measurement mode (pressure boosting method) In the second airtightness measurement mode, the Cv value is automatically measured using the pressure boosting method. The controller (110) increases the internal pressure of the storage space (5) by operating the air pump (231) as a pressure regulating unit. The controller (110) then determines the Cv value based on the rate at which the internal pressure increases. 【0161】 Specifically, as shown in Figure 14, in step ST21, the controller (110) operates the air pump (231) as a pressure regulating unit. The details of the control in step ST21 are the same as in step ST11. 【0162】 In step ST22, the controller (110) measures the first time (Δt1) until the internal pressure (Pi) rises from the first pressure (P1) to the second pressure (P2). In the second airtightness measurement mode, the first pressure (P1) is lower than the second pressure (P2). For example, the first pressure (P1) is set to 100 [kPa] and the second pressure (P2) is set to 300 [kPa]. As shown in Figure 14, the controller (110) measures the first time (Δt1) from the first time point (t1) when the internal pressure (Pi) is the first pressure (P1) to the second time point (t2) when the internal pressure (Pi) is the second pressure (P2). If the airtightness of the transport container (1) is low, the rate of increase of the internal pressure (Pi) will be lower, and the first time (Δt1) will be longer. If the airtightness of the transport container (1) is high, the rate of increase in internal pressure (Pi) will be high, and the first time (Δt1) will be shorter. Thus, the rate of increase in internal pressure, or more precisely, the time it takes for the internal pressure to increase to a predetermined pressure, serves as an indicator of the airtightness of the transport container (1). 【0163】 Next, in step ST23, the controller (110) obtains the internal pressure (Pi), external pressure (Po), differential pressure (ΔP), internal air temperature (Tr), and inflow flow rate (Qi) when the internal pressure (Pi) reaches the second pressure (P2). In the pressure boosting method, the inflow flow rate (Qi) corresponds to the control flow rate of the air pump (231). More precisely, the inflow flow rate (Qi) is the control flow rate of the pressurizing pump (231a) when air is transported into the internal space (5) by the pressurizing pump (231a), and the control flow rate of the depressurizing pump (231b) when air is transported by the depressurizing pump (231b). Alternatively, a flow meter may be installed in the flow path supplying air to the internal space (5) to directly measure the inflow flow rate (Qi). 【0164】 Next, in step ST24, the controller (110) calculates the Cv value based on equations (1), (2), and (3) in Figure 14. The details of the method for calculating the Cv value are the same as in the first airtightness measurement mode. 【0165】 (8-1-3) Third airtightness measurement mode (constant pressure method) In the third airtightness measurement mode, the Cv value is automatically measured using the constant pressure method. The controller (110) operates the air pump (231) as a pressure regulator. When the air pump (231) reaches a steady state, the internal pressure in the storage space (5) becomes constant. The controller (110) uses parameters such as the internal pressure (Pi) at this time to determine the Cv value. 【0166】 Specifically, as shown in Figure 15, in step ST31, the controller (110) operates the air pump (231) as a pressure regulating unit. The details of the control in step ST31 are the same as in step ST11. 【0167】 Next, in step ST32, the controller (110) determines whether the internal pressure (Pi) is constant. Here, "constant" means not only that the internal pressure (Pi) is maintained at a single value, but also that the internal pressure (Pi) is maintained within a predetermined range. In step ST32, the controller (110) determines whether the internal pressure (Pi) is within a predetermined range over a predetermined second time (Δt2). If the internal pressure (Pi) is constant over the predetermined second time (Δt2), the process proceeds to step ST33. 【0168】 In step ST33, the controller (110) obtains the internal pressure (Pi), external pressure (Po), differential pressure (ΔP), internal air temperature (Tr), and inflow rate (Qi) at the second time (Δt2). Here, these parameters may be values ​​at a specific point in the second time (Δt2) or may be average values ​​over the entire second time (Δt2). Then, in step ST34, the controller (110) calculates the Cv value based on equation (1) shown in Figure 14. When the internal pressure (Pi) is constant, the inflow rate (Qi) and outflow rate (Qo) are balanced. Therefore, the inflow rate (Qi) and outflow rate (Qo) at the second time (Δt2) are equal. Therefore, the Cv value can be determined by substituting the internal pressure (Pi), external pressure (Po), differential pressure (ΔP), internal air temperature (Tr), and inflow rate (Qi) at the second time (Δt2) into equation (4). Here, the inflow rate (Qi) is the control flow rate of the pressurizing pump (231a) when air is transported into the internal space (5) by the pressurizing pump (231a), and the control flow rate of the depressurizing pump (231b) when air is transported by the depressurizing pump (231b). Alternatively, a flow meter may be installed in the flow path supplying air to the internal space (5) to directly measure the inflow rate (Qi). 【0169】 (8-2) Estimation of the actual volume of the interior space After the Cv value is measured, the controller (110) performs an estimation operation to estimate the actual volume (Vs) of the internal space (5). In the estimation operation of this embodiment, the controller (110) estimates the actual volume (Vs) of the internal space (5) based on the Cv value obtained in one of the airtightness measurement modes described above and a first index indicating the rate of change of the internal pressure (Pi). The estimation operation includes a first estimation operation based on the depressurization method and a second estimation operation based on the pressure boosting method. 【0170】 (8-2-1) First estimated operation The first estimation operation estimates the actual volume (Vs) of the internal space (5) based on a first indicator that shows the rate of change in the decrease of the internal pressure. For example, when cargo is loaded into the internal space (5) and the actual volume (Vs) decreases, the rate of decrease of the internal pressure (Pi) in the depressurization method increases. Conversely, for example, when the amount of cargo in the internal space (5) decreases and the actual volume (Vs) increases, the rate of decrease of the internal pressure (Pi) in the depressurization method decreases. Therefore, in the first estimation operation, the actual volume (Vs) is estimated using the first time (Δt1) in the depressurization method for the internal pressure (Pi) as the first indicator. The controller (110) performs the first estimation operation shown in Figure 16 after the airtightness measurement mode described above. 【0171】 The processing in steps ST41 to ST45 of the first estimation operation is the same as steps ST11 to ST15 of the first airtightness measurement mode described above. That is, in steps ST41 to ST44, the controller (110) measures the first time (Δt1) until the internal pressure (Pi) decreases from the first pressure (P1) to the second pressure (P2). In step ST45, the controller (110) obtains the internal pressure (Pi), external pressure (Po), differential pressure (ΔP), and internal air temperature (Tr). 【0172】 Next, in step ST46, the controller (110) refers to the Cv value obtained in the airtightness measurement mode. This Cv value may be the value obtained in the first airtightness measurement mode, the second airtightness measurement mode, or the third airtightness measurement mode. 【0173】 Next, in step ST47, the controller (110) uses the parameters obtained in steps ST44 to ST46 to determine the actual volume (Vs) based on equations (1), (2), and (3). In equation (1), the Cv value measured in airtightness measurement mode is used. Therefore, the outflow rate (Qo) can be determined from equation (1). By substituting this outflow rate (Qo) and the other parameters into equations (2) and (3), V1 can be determined. V1 is the gas volume of the storage space (5), that is, the actual volume (Vs) obtained by subtracting the volume of the cargo from the total volume of the storage space (5). 【0174】 (8-2-2) Second estimated operation The second estimation operation estimates the actual volume (Vs) of the internal space (5) based on a first indicator that shows the rate of increase in the internal pressure. For example, when cargo is loaded into the internal space (5) and the actual volume (Vs) decreases, the rate of increase in the internal pressure (Pi) in the pressure-boosting method increases. Conversely, for example, when the amount of cargo in the internal space (5) decreases and the actual volume (Vs) increases, the rate of increase in the internal pressure (Pi) in the pressure-boosting method decreases. Therefore, in the second estimation operation, the actual volume (Vs) is estimated using the first time (Δt1) in the pressure-boosting method for the internal pressure (Pi) as the first indicator. The controller (110) performs the second estimation operation shown in Figure 17 after the airtightness measurement mode described above. 【0175】 The processing in steps ST51 to ST53 of the second estimation operation is the same as steps ST21 to ST23 of the second airtightness measurement mode described above. That is, in steps ST51 and ST52, the controller (110) measures the first time (Δt1) until the internal pressure (Pi) increases from the first pressure (P1) to the second pressure (P2). In step ST53, the controller (110) obtains the internal pressure (Pi), external pressure (Po), differential pressure (ΔP), internal air temperature (Tr), and inflow flow rate (Qi). 【0176】 Next, in step ST54, the controller (110) refers to the Cv value obtained in the airtightness measurement mode. This Cv value may be the value obtained in the first airtightness measurement mode, the second airtightness measurement mode, or the third airtightness measurement mode. Next, in step ST55, the controller (110) uses the parameters obtained in steps ST53 and ST54 to determine the actual volume (Vs) based on equations (1), (2), and (3) in the same manner as in the first estimation operation. 【0177】 (8-2-3) Timing of estimated operation The controller (110) can perform estimated operations in conjunction with the operating mode of the air composition adjustment device (100). 【0178】 As shown in Figure 18(a), the controller (110) performs the first estimation operation after switching from the above-described outside air introduction operation (more precisely, outside air introduction mode) to the breathing mode. In the outside air introduction operation, outside air is supplied to the interior space (5) by the pressurizing pump (231a), increasing the internal pressure (Pi). Subsequently, in breathing mode, the pressurizing pump (231a) stops. Therefore, in breathing mode, the first time (Δt1) until the internal pressure (Pi) decreases from the first pressure (P1) to the second pressure (P2) can be measured, and furthermore, the actual volume (Vs) can be determined. 【0179】 As shown in Figure 18(b), the controller (110) performs the first estimation operation after switching from the gas supply operation (more precisely, the 5% oxygen mode or the oxygen outside air introduction mode) to the breathing mode. In the gas supply operation, nitrogen-enriched gas is supplied to the interior space (5) by the depressurization pump (231b), increasing the interior pressure (Pi). Subsequently, in breathing mode, the depressurization pump (231b) stops. Therefore, in breathing mode, the first time (Δt1) until the interior pressure (Pi) decreases from the first pressure (P1) to the second pressure (P2) can be measured, and furthermore, the actual volume (Vs) can be determined. 【0180】 As shown in Figure 18(c), the controller (110) performs a second estimation operation after switching from the breathing mode described above to the outside air introduction operation (more precisely, the outside air introduction mode). At the start of the outside air introduction operation, outside air is supplied to the interior space (5) by the pressurizing pump (231a), increasing the internal pressure (Pi). Therefore, at the start of the outside air introduction operation, the first time (Δt1) until the internal pressure (Pi) increases from the first pressure (P1) to the second pressure (P2) can be measured, and furthermore, the actual volume (Vs) can be determined. 【0181】 As shown in Figure 18(d), the controller (110) performs a second estimation operation after switching from the breathing mode described above to a gas supply operation (more precisely, the 5% oxygen mode or the oxygen outside air introduction mode). At the start of the gas supply operation, nitrogen-enriched gas is supplied to the interior space (5) by the depressurization pump (231b), increasing the interior pressure (Pi). Therefore, at the start of the gas supply operation, the first time (Δt1) until the interior pressure (Pi) increases from the first pressure (P1) to the second pressure (P2) can be measured, and furthermore, the actual volume (Vs) can be determined. 【0182】 (8-3) Estimation of respiratory volume The controller (110) performs a respiration rate estimation operation to determine the respiration rate of the cargo (more precisely, fruits, vegetables, flowers, etc.) based on the actual volume (Vs). The respiration rate estimation operation includes a first respiration rate estimation operation and a second respiration rate estimation operation. In the first respiration rate estimation operation, the controller (110) estimates the oxygen consumption rate (Ro) as the respiration rate of the fruits, vegetables, or flowers. In the second respiration rate estimation operation, the controller (110) estimates the carbon dioxide production rate (Rc) as the respiration rate of the fruits, vegetables, or flowers. 【0183】 (8-3-1) First respiratory volume estimation operation In the first respiratory volume estimation operation shown in Figure 19, in step ST61, the controller (110) causes the gas supply operation to be performed. In step ST61, the controller (110) causes nitrogen-enriched gas with adjusted oxygen concentration to be supplied to the chamber space (5) by the gas supply operation. The gas supply operation may be in 8% oxygen concentration mode or 5% oxygen concentration mode. 【0184】 Next, in step ST62, the controller (110) measures the oxygen concentration (first oxygen concentration (Ca)) at the fifth time point (t5) in the interior space (5) and the oxygen concentration (second oxygen concentration (Cb)) at the sixth time point (t6) in the interior space (5) using the oxygen sensor (161). 【0185】 Next, in step ST63, the controller (110) estimates the oxygen consumption rate (Ro) using equation (4) in Figure 19. Here, equation (4) is the theoretical formula for the second oxygen concentration (Cb) at the sixth time step (t6). In equation (4), Vs is the actual volume of the internal space (5), and corresponds to the actual volume of internal air present in the internal space (5). Δt3 is the time (third hour) between the fifth time step (t5) and the sixth time step (t6). Qi is the inflow rate of nitrogen-enriched gas supplied to the internal space (5). Co is the oxygen concentration of the nitrogen-enriched gas supplied to the internal space (5), which is 8% in the 8% oxygen concentration mode and 5% in the 5% oxygen concentration mode. By substituting each parameter into equation (4), the controller (110) can determine the oxygen consumption rate (Ro). 【0186】 In step ST61, the controller (110) may perform an outside air introduction operation instead of a gas supply operation. In this case, the inflow rate (Qi) in equation (4) becomes the flow rate of outside air supplied to the interior space (5), and the supplied oxygen concentration (Co) in equation (4) becomes the oxygen concentration of the outside air (approximately 21%). If outside air flows into the interior space (5) from another route, the flow rate of this incoming air and its oxygen concentration (21%) may be added to the numerator of equation (4), and the flow rate of this incoming air may be added to the denominator. The controller (110) can estimate this air flow rate based on the Cv value or the first index. 【0187】 (8-3-2) Second respiratory volume estimation operation In the second respiratory volume estimation operation shown in Figure 20, in step ST71, the controller (110) initiates a gas supply operation. In step ST71, the controller (110) supplies nitrogen-enriched gas with adjusted oxygen concentration into the chamber space (5) through the gas supply operation. The gas supply operation may be in 8% oxygen concentration mode or 5% oxygen concentration mode. 【0188】 Next, in step ST72, the controller (110) measures the carbon dioxide concentration (first carbon dioxide concentration (Cc)) at the seventh time point (t7) in the interior space (5) and the carbon dioxide concentration (second carbon dioxide concentration (Cd)) at the eighth time point (t8) in the interior space (5) using the carbon dioxide sensor (162). 【0189】 Next, in step ST73, the controller (110) estimates the carbon dioxide generation rate (Rc) using equation (5) in Figure 20. Here, equation (5) is the theoretical formula for the second carbon dioxide concentration (Cd) at time 8 (t8). In equation (5), Δt4 is the time (4th hour) between time 7 (t7) and time 8 (t8). In the numerator of equation (5), the carbon dioxide supplied to the interior space (5) by the supply of nitrogen-enriched gas is ignored because the carbon dioxide concentration is extremely low, approximately 300 ppm. By substituting each parameter into equation (5), the controller (110) can determine the carbon dioxide generation rate (Rc). 【0190】 In step ST71, the controller (110) may perform an outside air introduction operation instead of a gas supply operation. In this case as well, in equation (4), carbon dioxide in the outside air supplied to the interior space (5) can be ignored. If outside air flows into the interior space (5) from another route, the flow rate of this incoming air may be added to the denominator of equation (5). The controller (110) can estimate this air flow rate based on the Cv value or the first index. 【0191】 (10) Details of concentration adjustment mode Next, the details of the concentration control mode will be explained with reference to Figures 21 to 24. In the concentration control mode, the controller (110) coordinately performs flow rate control, which adjusts the flow rate of the first air supplied from the supply path (S) to the interior space (5), and concentration control, which adjusts the composition of this first air. In flow rate control, the controller (110) adjusts the flow rate of the first air (hereinafter also referred to as the first flow rate (Q1)) while the air pump (231) is operating, so that the carbon dioxide concentration of the components in the interior air reaches the set carbon dioxide concentration (SP2). In concentration control, the controller (110) adjusts the oxygen concentration of the first air (hereinafter also referred to as the first oxygen concentration (C1)) while the air pump (231) is operating, so that the oxygen concentration of the components in the interior air reaches the set oxygen concentration (SP1). 【0192】 (10-1) Basic Flow Figure 21 shows the basic flow of the concentration control mode. When a command to operate the concentration control mode is input to the controller (110) in response to user operation (YES in step ST81), in step ST82 the controller (110) starts the concentration control mode. 【0193】 In step ST83, the controller (110) calculates the target flow rate (Qt) to satisfy the set carbon dioxide concentration (SP2) based on equation (6) in Figure 21. Here, Rc is the carbon dioxide generation rate of the cargo, obtained in the second respiration volume estimation operation, and Qt is the target flow rate of the first air. By controlling the first flow rate (Q1) of the first air to the target flow rate (Qt), the carbon dioxide concentration in the storage space (5) converges to the set carbon dioxide concentration (SP2). Note that equation (6) ignores the carbon dioxide concentration contained in the first air. This is because the carbon dioxide concentration contained in the first air is extremely low, for example, about 300 ppm. 【0194】 In step ST84, the controller (110) calculates the target oxygen concentration (C1) to satisfy the set oxygen concentration (SP1) based on equations (6) and (7) in Figure 21. Here, Ro is the oxygen consumption rate of the cargo obtained in the first respiration volume estimation operation, and Ct is the target oxygen concentration of the first air. By controlling the oxygen concentration of the first air (C1) to the target concentration (Ct), the oxygen concentration of the air inside the warehouse converges to the set oxygen concentration (SP1). 【0195】 Next, the controller (110) coordinately performs the flow rate control in step ST85 and the concentration control in step ST86. When a command to terminate the concentration adjustment mode is input to the controller (110) in response to user operation (YES in step ST87), the controller (110) terminates the concentration adjustment mode in step ST88. 【0196】 (10-2) Flow control The flow rate control of this embodiment includes a first flow rate control and a second flow rate control. The first flow rate control is a control mode that brings the first flow rate (Q1) of the first air closer to the target flow rate (Qt) determined in step ST83. In the first flow rate control, the first flow rate (Q1) of the first air is set to the target flow rate (Qt) required to satisfy the set carbon dioxide concentration (SP2). Therefore, in the first flow rate control, the carbon dioxide concentration of the air inside the chamber can be quickly brought closer to the set value. The second flow rate control increases or decreases the first flow rate (Q1) so that the carbon dioxide concentration of the air inside the chamber approaches the set carbon dioxide concentration (SP2). In the second flow rate control, the carbon dioxide concentration of the air inside the chamber can be brought closer to the set value with high accuracy. The controller (110) switches between the first flow rate control and the second flow rate control based on a first condition. The first condition is a condition that indicates that the carbon dioxide concentration in the air inside the chamber is close to the set value. 【0197】 Specifically, as shown in Figure 22, in step ST101, the controller (110) determines whether or not the first condition is met. The first condition in this embodiment is whether or not the carbon dioxide concentration in the internal space (5) (hereinafter also referred to as the internal carbon dioxide concentration (Cs2)) is within a predetermined first range that includes a set value. The first range is within the range of the set carbon dioxide concentration (SP2) ± α%. More precisely, the first range is within the range of SP2 - SP2 × α% or more and SP2 + SP_CO2 × α% or less. α is set to, for example, 0.1. The internal carbon dioxide concentration (Cs2) is detected by the carbon dioxide sensor (162). 【0198】 In step ST101, if the first condition is not met, that is, if the carbon dioxide concentration (Cs2) inside the chamber is not within the first range, the controller (110) performs the first flow rate control in step ST102. In the first flow rate control, the controller (110) controls the first flow rate (Q1) of the first air to the target flow rate (Qt). As a result, the carbon dioxide concentration (Cs2) inside the chamber can be quickly brought closer to the set carbon dioxide concentration (SP2). Details of the specific method for adjusting the flow rate of the first air will be described later. 【0199】 In step ST101, if the first condition is met, that is, if the carbon dioxide concentration (Cs2) inside the chamber is within the first range, the controller (110) performs second flow rate control. In second flow rate control, the controller (110) adjusts the first flow rate (Q1) of the first air so that the carbon dioxide concentration (Cs2) inside the chamber becomes the set carbon dioxide concentration (SP2). Specifically, in step ST103, if the carbon dioxide concentration (Cs2) inside the chamber is greater than the set carbon dioxide concentration (SP2), the controller (110) increases the current first flow rate (Q1) by a predetermined amount in step ST105. As the first flow rate (Q1) increases, the carbon dioxide concentration (Cs2) inside the chamber decreases. In step ST104, if the carbon dioxide concentration (Cs2) inside the chamber is less than the set carbon dioxide concentration (SP2), the controller (110) decreases the current first flow rate (Q1) by a predetermined amount in step ST106. As the first flow rate (Q1) decreases, the carbon dioxide concentration (Cs2) inside the warehouse increases due to the respiration of the cargo. 【0200】 Thus, in this embodiment, when the difference between the carbon dioxide concentration inside the chamber (Cs2) and the set carbon dioxide concentration (SP2) is large, the first flow rate control is executed, and when the difference between the carbon dioxide concentration inside the chamber (Cs2) and the set carbon dioxide concentration (SP2) is small, the second flow rate control is executed. As a result, the carbon dioxide concentration inside the chamber (Cs2) can be quickly and accurately brought to the set carbon dioxide concentration (SP2). 【0201】 (10-3) Concentration control The concentration control in this embodiment includes a first concentration control and a second concentration control. The first concentration control is a control mode that brings the oxygen concentration (C1) of the first air closer to the target concentration (Ct) determined in step ST84. In the first concentration control, the oxygen concentration (C1) of the first air is set to the target concentration (Ct) that satisfies the set oxygen concentration (SP1). Therefore, in the first concentration control, the oxygen concentration of the air inside the chamber can be quickly brought closer to the set value. In the second concentration control, the oxygen concentration (C1) of the first air is increased or decreased so that the oxygen concentration of the air inside the chamber approaches the set oxygen concentration (SP1). In the second concentration control, the oxygen concentration of the air inside the chamber can be brought closer to the set value with high accuracy. The controller (110) switches between the first concentration control and the second concentration control based on a second condition. The second condition is a condition that indicates that the oxygen concentration in the air inside the chamber is close to the set value. 【0202】 Specifically, as shown in Figure 23, in step ST111, the controller (110) determines whether the second condition is met. The second condition in this embodiment is whether the oxygen concentration in the internal space (5) (hereinafter also referred to as the internal oxygen concentration (Cs1)) is within a predetermined second range that includes a set value. The second range is within the range of the set oxygen concentration (SP1) ± β%. More precisely, the second range is within the range of SP1 - SP1 × β% or more and SP1 + SP1 × β% or less. β is set to, for example, 0.1. The internal oxygen concentration (Cs1) is detected by the oxygen sensor (161). 【0203】 If the second condition is not met in step ST111, that is, if the oxygen concentration inside the chamber (Cs1) is not within the second range, the controller (110) performs the first concentration control in step ST112. In the first concentration control, the controller (110) controls the oxygen concentration of the first air (C1) to the target concentration (Ct). As a result, the oxygen concentration inside the chamber (Cs1) can be quickly brought closer to the set oxygen concentration (SP1). Details of the specific method for adjusting the oxygen concentration of the first air (C1) will be described later. 【0204】 In step ST113, if the second condition is met, that is, if the oxygen concentration inside the chamber (Cs1) is within the second range, the controller (110) performs the second concentration control. In the second concentration control, the controller (110) adjusts the oxygen concentration (C1) of the first air so that the oxygen concentration inside the chamber (Cs1) becomes the set oxygen concentration (SP1). Specifically, in step ST113, if the oxygen concentration inside the chamber (Cs1) is greater than the set oxygen concentration (SP1), in step ST115, the controller (110) decreases the current oxygen concentration (C1) by a predetermined amount. As a result, the oxygen concentration inside the chamber (Cs1) decreases and approaches the set oxygen concentration (SP1). In step ST114, if the oxygen concentration inside the chamber (Cs1) is less than the set oxygen concentration (SP1), in step ST116, the controller (110) increases the current oxygen concentration (C1) of the first air by a predetermined amount. As a result, the oxygen concentration inside the chamber (Cs1) increases and approaches the set oxygen concentration (SP1). 【0205】 Thus, in this embodiment, a first concentration control is performed when the oxygen concentration inside the chamber (Cs1) is far from the set oxygen concentration (SP1), and a second concentration control is performed when the oxygen concentration inside the chamber (Cs1) is close to the set oxygen concentration (SP1). As a result, the oxygen concentration inside the chamber (Cs1) can be quickly and accurately brought to the set oxygen concentration (SP1). 【0206】 (10-4) Specific examples of flow rate control In this embodiment, the controller (110) controls the air pump (231) to adjust the flow rate of the first air supplied from the supply path (S) to the storage space (5) (first flow rate (Q1)). Specifically, the controller (110) controls the rotational speed of the air pump (231), specifically the motor's operating frequency. This allows the first flow rate (Q1) to be controlled to a target flow rate (Qt) in the first flow rate control. In the second flow rate control, the first flow rate (Q1) can be increased or decreased by a predetermined amount. 【0207】 Furthermore, in order to improve the controllability of the first flow rate (Q1), the first flow rate (Q1) may be measured. To measure the first flow rate (Q1), a flow meter may be installed in the supply path (S), specifically in the gas supply pipe (275). The controller (110) performs feedback control of the first flow rate (Q1) based on the value detected by the flow meter. 【0208】 Alternatively, the controller (110) can estimate the first flow rate (Q1) based on the Cv value. Specifically, when the internal pressure (Pi) is constant during the operation of the air pump (231), the inflow flow rate (Qi) of the first air can be determined using equation (1) by the constant pressure method shown in Figure 15. In this case, the controller (110) can estimate the inflow flow rate (Qi), i.e., the first flow rate (Q1), using equation (1) with the previously determined Cv value, internal air temperature (Tr), differential pressure (ΔP), internal pressure (Pi), and external pressure (Po). 【0209】 (10-5) Specific examples of concentration control In the concentration control described above, the controller (110) adjusts the oxygen concentration (C1) of the first air. The specific method of concentration control will now be explained. The controller (110) adjusts the oxygen concentration (C1) of the first air by controlling the timing of opening and closing the gas discharge valve (272) for discharging the processed gas (nitrogen-enriched gas) processed in the air processing unit (95) to the space outside the chamber (6). 【0210】 Figure 24 is a timing chart showing the oxygen concentration of the processed gas immediately after switching between the first and second operations described above, and the timing of opening and closing of the gas discharge valve (272) and gas supply valve (273). In Figure 24, ts indicates the time of switching between the first and second operations. At the beginning of the first and second operations, the oxygen concentration of the processed gas is high. This is because, as described above, at the beginning of each operation, outside air remains in the adsorption cylinders (234, 235) and piping, etc., so a nitrogen-enriched gas with a relatively high oxygen concentration is generated. On the other hand, at the end of the first and second operations, the oxygen concentration of the processed gas decreases rapidly. This is because the pressure inside the adsorption cylinders (234, 235) decreases from the initial stage, causing more nitrogen components to be desorbed and the oxygen concentration to decrease. In this embodiment, the oxygen concentration (C1) of the first air is adjusted by utilizing the change in oxygen concentration during the period of each operation. 【0211】 In the first control example shown in Figure 24(a), the oxygen concentration (C1) of the first air is adjusted to a low concentration. In this example, the controller (110) opens the gas discharge valve (272) and closes the gas supply valve (273) during the period TA when the oxygen concentration of the process gas is high. As a result, the process gas with a high oxygen concentration is discharged to the outside space (6). During the period TB when the oxygen concentration of the process gas is low, the controller (110) closes the gas discharge valve (272) and opens the gas supply valve (273). As a result, the process gas with a low oxygen concentration is supplied to the inside space (5) as the first air. Thus, in the first control example, the process gas with a high oxygen concentration is discharged to the outside space (6) during period TA, and the process gas with a low oxygen concentration is supplied to the inside space (5) during period TB. This adjusts the oxygen concentration (C1) of the first air to a low concentration as an average over the entire period of each operation. 【0212】 In the second control example shown in Figure 24(b), the oxygen concentration (C1) of the first air is adjusted to a medium concentration. In this example, the controller (110) opens the gas discharge valve (272) and closes the gas supply valve (273) during a portion of period TA (for example, the first half). As a result, during the first half of period TA, a process gas with a high oxygen concentration is discharged to the outside space (6). During the remainder of period TA (the second half), the controller (110) closes the gas discharge valve (272) and opens the gas supply valve (273). As a result, during the remainder of period TA, a process gas with a high oxygen concentration is supplied to the inside space (5) as the first air. During period TB, the controller (110) closes the gas discharge valve (272) and opens the gas supply valve (273). As a result, during period TB, a process gas with a low oxygen concentration is supplied to the inside space (5) as the first air. In this second control example, during a portion of period TA, a process gas with a high oxygen concentration is discharged into the space outside the chamber (6), during the remainder of period TA, a process gas with a high oxygen concentration is supplied into the space inside the chamber (5), and during period TB, a process gas with a low oxygen concentration is supplied to the space inside the chamber (5). As a result, the oxygen concentration of the first air (C1) is adjusted to a medium concentration as an average over the entire period of each operation. 【0213】 In the third control example shown in Figure 24(c), the oxygen concentration (C1) of the first air is adjusted to a high concentration. In this example, the controller (110) closes the gas discharge valve (272) and opens the gas supply valve (273) during period TA. As a result, during period TA, a process gas with a high oxygen concentration is supplied to the interior space (5) as the first air. During period TB, the controller (110) closes the gas discharge valve (272) and opens the gas supply valve (273). As a result, a process gas with a low oxygen concentration is discharged to the exterior space (6). Thus, in the third control example, during period TA, a process gas with a high oxygen concentration is supplied to the interior space (5), and during period TB, a process gas with a low oxygen concentration is discharged to the exterior space (6). This adjusts the oxygen concentration (C1) of the first air to a high concentration on average over the entire duration of each operation. 【0214】 As described above, the controller (110) switches the timing of opening and closing the gas discharge valve (272) in at least three patterns. In each control example, the controller (110) may also keep the gas supply valve (273) open at all times during each operation. In this case, by opening the gas discharge valve (272), some of the processed gas is discharged to the space outside the chamber (6), and the remaining processed gas is supplied to the space inside the chamber (5). 【0215】 (11) Characteristics of the embodiment (11-1) The controller (110) performs flow control during the operation of the air pump (231), which is the air transport unit, by adjusting the flow rate of the first air to at least so that the concentration of components in the air inside the storage unit reaches a set value. Specifically, in concentration adjustment mode, the controller (110) adjusts the first flow rate (Q1) of the first air so that the carbon dioxide concentration in the air inside the storage unit reaches a set carbon dioxide concentration (SP2). Therefore, the carbon dioxide concentration in the air inside the storage unit can be brought to the set carbon dioxide concentration (SP2) without switching modes between multiple modes, such as a 5% oxygen concentration mode, an 8% oxygen concentration mode, an outside air introduction mode, and a breathing mode. Consequently, the range of change in the carbon dioxide concentration in the air inside the storage unit can be reduced when switching modes, thus maintaining the freshness of fruits, vegetables, and flowers. 【0216】 The controller (110) performs concentration control during the operation of the air pump (231), which is the air transport unit, by adjusting the concentration of the components in the first air so that the concentration of the components in the air inside the storage unit reaches a set value. Specifically, in concentration adjustment mode, the controller (110) adjusts the oxygen concentration (C1) of the first air so that the oxygen concentration in the air inside the storage unit reaches the set oxygen concentration (SP1). Therefore, the oxygen concentration of the air inside the storage unit can be brought to the set oxygen concentration (SP1) without switching modes. Consequently, the range of change in the oxygen concentration of the air inside the storage unit can be reduced when switching modes, thus maintaining the freshness of fruits, vegetables, and flowers. 【0217】 In concentration control mode, the air pump (231) is not stopped, for example, as in breathing mode. In other words, in concentration control mode, the controller (110) keeps the air pump (231) running at all times. Therefore, the operation of the air pump (231) can maintain positive pressure in the storage space (5). Consequently, the intrusion of outside air into the storage space (5) can be suppressed. As a result, changes in the carbon dioxide concentration and oxygen concentration in the storage space (5) caused by the intrusion of outside air can be suppressed. In addition, an increase in the cooling load of the transport refrigeration unit (10) caused by the intrusion of outside air can be suppressed. 【0218】 (11-2) The controller (110) adjusts the first flow rate (Q1) of the first air by controlling a variable flow rate air pump (231) in flow control. Therefore, the first flow rate (Q1) can be easily and precisely adjusted. 【0219】 The controller (110) adjusts the oxygen concentration (C1) of the first air by adjusting the opening and closing timing of the gas discharge valve (272) in concentration control. Therefore, the oxygen concentration (C1) of the first air can be easily adjusted without using other oxygen sources. 【0220】 (11-3) The controller (110) determines the target flow rate to bring the carbon dioxide concentration in the air inside the chamber to the set oxygen concentration (SP1). In the first flow rate control, the controller (110) adjusts the first flow rate of the first air to the target flow rate (Qt). This control allows the carbon dioxide concentration in the chamber space (5) to quickly converge to the set carbon dioxide concentration (SP2). Since the carbon dioxide concentration in the first air is extremely low, the target flow rate (Qt) of the first air can be determined without considering the carbon dioxide concentration in the first air. 【0221】 The controller (110) estimates the carbon dioxide generation rate (Rc) of fruits, vegetables, or flowers in the storage space (5) and determines the target flow rate (Qt) based on the estimated carbon dioxide generation rate (Rc). By determining the target flow rate (Qt) while considering the carbon dioxide generation rate (Rc) of fruits, vegetables, or flowers, the carbon dioxide concentration in the storage space (5) can be maintained at a more appropriate value. 【0222】 The controller (110) estimates the carbon dioxide generation rate (Rc) based on the actual volume (Vs) of the internal space (5) and the carbon dioxide concentration in the internal air. Therefore, the carbon dioxide generation rate (Rc) can be accurately estimated. 【0223】 (11-4) The controller (110) determines the target concentration (Ct) required to bring the oxygen concentration in the air inside the chamber to the set oxygen concentration (SP1). In concentration control, the controller (110) adjusts the oxygen concentration of the first air to the target concentration (Ct). This control allows the oxygen concentration in the chamber space (5) to quickly converge to the set oxygen concentration (SP1). 【0224】 The controller (110) estimates the oxygen consumption rate (Ro) of fruits, vegetables, or flowers in the storage space (5) and determines the target flow rate (Qt) based on the estimated oxygen consumption rate (Ro). This control allows the oxygen concentration in the storage space (5) to quickly converge to the set oxygen concentration (SP1). 【0225】 The controller (110) estimates the oxygen consumption rate (Ro) of fruits, vegetables, or flowers in the storage space (5) and determines the target flow rate (Qt) based on the estimated oxygen consumption rate (Ro). By determining the target flow rate (Qt) while considering the oxygen consumption rate (Ro) of fruits, vegetables, or flowers, the oxygen concentration in the storage space (5) can be maintained at a more appropriate value. 【0226】 The controller (110) estimates the oxygen consumption rate (Ro) based on the actual volume (Vs) of the interior space (5) and the oxygen concentration in the air inside the interior. Therefore, the oxygen consumption rate can be accurately estimated. 【0227】 (11-5) The air composition adjustment device (90) includes an air pump (231) as a pressure adjustment unit that changes the pressure in the internal space (5), and a differential pressure sensor (170) as a pressure detection unit that detects the internal pressure (Pi) in the internal space (5). When the internal pressure (Pi) changes, the controller (110) estimates the actual volume (Vs) based on a first index that indicates the rate of change of the internal pressure (Pi). Therefore, the actual volume (Vs) can be automatically estimated using the air pump (231) used for transporting the first air and the differential pressure sensor (170) used for managing the transport container (1). 【0228】 In particular, the controller (110) estimates the actual volume (Vs) using the Cv value. Therefore, the actual volume (Vs) can be estimated with high accuracy. Furthermore, the Cv value can also be used for the management and evaluation of the transport container (1). 【0229】 (11-6) The controller (110) performs a first flow rate control, which adjusts the flow rate of the first air to a target flow rate (Qt), and a second flow rate control, which adjusts the flow rate of the first air so that the carbon dioxide concentration (Cs2) inside the chamber, detected by the carbon dioxide concentration sensors (161, 162), becomes a set carbon dioxide concentration (SP2). The first flow rate control can quickly bring the carbon dioxide concentration of the air inside the chamber closer to the set carbon dioxide concentration (SP2), and the second flow rate control can accurately bring the carbon dioxide concentration of the air inside the chamber closer to the set carbon dioxide concentration (SP2). 【0230】 The controller (110) executes the first flow rate control when the first condition, which indicates that the carbon dioxide concentration in the air inside the chamber is close to the set carbon dioxide concentration (SP2), is not met. The controller (110) executes the second flow rate control when the first condition is met. This allows the carbon dioxide concentration in the air inside the chamber to converge to the set carbon dioxide concentration (SP2) quickly and accurately. 【0231】 (11-7) The controller (110) performs a first concentration control, which adjusts the oxygen concentration (C1) of the first air to a target concentration (Ct), and a second concentration control, which adjusts the oxygen concentration (C1) of the first air so that the oxygen concentration (Cs1) inside the chamber detected by the oxygen concentration sensors (161, 162) becomes the set oxygen concentration (SP1). The first concentration control can quickly bring the carbon dioxide concentration of the inside air closer to the set carbon dioxide concentration (SP2), and the second concentration control can accurately bring the oxygen concentration of the inside air closer to the set oxygen concentration (SP1). 【0232】 The controller (110) executes the first concentration control when the second condition, which indicates that the oxygen concentration (C1) in the air inside the chamber is close to the set oxygen concentration (SP1), is not met. The controller (110) executes the second concentration control when the second condition is met. This allows the oxygen concentration in the air inside the chamber to converge to the set oxygen concentration (SP1) quickly and accurately. 【0233】 (12) Modified examples of embodiments The above-described embodiment may also have the following modified configuration. In principle, the differences from the above embodiment will be explained below. 【0234】 (12-1) Variation 1 The air composition adjustment device (90) of Modification 1 shown in Figure 25 has a gas storage tank (290) and an auxiliary pump (291). The gas storage tank (290) and the auxiliary pump (291) are installed in the supply passage (S), specifically in the gas supply pipe (275). The gas storage tank (290) stores nitrogen-enriched gas (low-concentration oxygen gas) after treatment in the air processing unit (95). The auxiliary pump (291) transports the nitrogen-enriched gas stored in the gas storage tank (290) and supplies it to the interior space (5). The auxiliary pump (291) is a variable flow rate pump. The air pump (231) in Modification 1 is a fixed flow rate pump. The gas storage tank (290) and the auxiliary pump (291) are located outside the unit case (201). 【0235】 In Modification 1, the processed gas, whose composition has been adjusted in the air processing unit (95) by the air pump (231), flows through the gas supply path (S). At this time, the controller (110) adjusts the first flow rate (Q1) of the first air by controlling the auxiliary pump (291) in flow rate control. The gas storage tank (290) and the auxiliary pump (291) may be provided in a flow path provided in parallel with the gas supply pipe (275) in the supply path (S). 【0236】 (12-2) Variation 2 The air composition adjustment device (90) of Modified Example 2 has an outside air inlet that introduces outside air into the interior space (5) as second air without going through the supply passage (S). The outside air inlet of Modified Example 2 is a ventilation device (40). The ventilation device (40) supplies outside air to the interior space (5) through the supply air communication port (41a). The ventilation device (40) has an interior fan (35) that constitutes the supply air fan. In flow rate control, the controller (110) adjusts the flow rate of the first air introduced into the interior space (5) from the supply passage (S) and the flow rate of the second air supplied to the interior space (5) by the ventilation device (40) so that the components in the interior air (e.g., carbon dioxide concentration) become set values. The outside air inlet may also be an air pump that supplies outside air to the interior space (5) via a flow path different from the supply passage (S). 【0237】 (12-3) Variation 3 In the air composition adjustment device (90) of Modified Example 3, the bypass valve (256) of the bypass connecting pipe (255) is configured as a flow control valve. The bypass valve (256) is an electrically operated valve with an adjustable opening. As shown in Figure 26, in the concentration control of Modified Example 3, the processed gas (nitrogen-enriched gas) processed in the air processing unit (95) and the outside air flowing through the bypass connecting pipe (255) are mixed in the gas supply pipe (275), which is the second flow path. The mixing ratio of the processed gas and the outside air corresponds to the opening of the bypass valve (256). In concentration control, the controller (110) adjusts the opening of the bypass valve (256), or in other words, the mixing ratio, so that the oxygen concentration of the air inside the chamber becomes a set value. In flow control, the controller (110) may also adjust the flow rate of the first air by adjusting the opening of the bypass valve (256). 【0238】 (12-4) Modification 4 The controller (110) may also consider the amount of outside air introduced from the outside space (6) into the inside space (5) in equations (6) and (7) of Figure 21 for estimating the respiration rate. In this case, in equation (6), the inflow rate of outside air is added to the denominator. In equation (7), the product of the inflow rate of outside air and the oxygen concentration (21%) is added to the numerator, and the inflow rate of outside air is added to the denominator. The inflow rate of outside air can be determined, for example, by subtracting the flow rate of the first air (Q1), which is determined by the control value of the air pump (231), from the inflow rate (Qi) obtained by equation (1), using the previously determined Cv value, the internal air temperature (Tr), the differential pressure (ΔP), the internal pressure (Pi), and the external pressure (Po). The controller (110) performs the control described above if the internal pressure (Pi) detected by the differential pressure sensor (170), which is a pressure detection unit, is positive, and performs the control described in Modification 4 if the internal pressure (Pi) is negative. 【0239】 (12-5) Variation 5 In Modification 5, the first condition for switching between the first flow rate control and the second flow rate control differs from that of the embodiment. The first condition in Modification 5 is that the elapsed time since the start of operation in concentration adjustment mode is longer than a predetermined time. Specifically, the controller (110) executes the first flow rate control when the concentration adjustment mode starts. This is because the carbon dioxide concentration in the air inside the chamber is far from the set value when the concentration adjustment mode starts. Subsequently, when the elapsed time becomes longer than the predetermined time, the first condition is met, and the controller (110) executes the second flow rate control. 【0240】 In Modification 5, the second condition for switching between the first concentration control and the second concentration control differs from that of the embodiment. The second condition in Modification 5 is that the elapsed time since the start of operation in concentration adjustment mode is longer than a predetermined time. Specifically, the controller (110) executes the first concentration control at the start of concentration adjustment mode. This is because at the start of concentration adjustment mode, the carbon dioxide concentration in the air inside the chamber is far from the set value. Subsequently, when the elapsed time becomes longer than the predetermined time, the second condition is met, and the controller (110) executes the second concentration control. 【0241】 (13) Other embodiments The controller (110) may adjust the flow rate of the first air in flow rate control so that the concentration of other components in the chamber air reaches a set value. The controller (110) may adjust the concentration of the first air in concentration control so that the concentration of other components in the chamber air reaches a set value. The controller may perform only flow rate control and not concentration control. The controller (110) may perform only either the first flow rate control or the second flow rate control. The controller (110) may perform only either the first concentration control or the second concentration control. 【0242】 The air composition adjustment device (90) may supply the processed gas, after adsorbing predetermined components in the air processing unit (95), as first air to the chamber space (5). In this case, the controller (110) can adjust the concentration of the components in the first air by adjusting the opening and closing timing of the gas discharge valve (272). This is because the concentration of the components in the gas processed by the adsorption operation also changes during that period. 【0243】 The air composition adjustment device (90) may have a flow path for mixing the first gas desorbed from the adsorption cylinders (234, 235) during the desorption operation with the second gas that has passed through the adsorption cylinders (234, 235), which are the adsorption parts during the adsorption operation, and a control valve for adjusting the mixing ratio of these gases. The controller (110) may adjust the concentration of the components of the first air by adjusting this mixing ratio. 【0244】 The air composition control device (90) may be configured not to perform any modes other than the concentration control mode. 【0245】 The controller (110) may estimate the carbon dioxide generation rate and oxygen consumption rate by other means, such as by the values ​​detected by the sensor. 【0246】 The air composition adjustment device (90) may measure the actual volume (Vs) of the internal space (5) using, for example, an ultrasonic sensor or a camera that images the internal space (5). 【0247】 The pressure adjustment unit used to estimate the actual volume (Vs) may be configured other than an air pump. Means for increasing the internal pressure (Pi) include a heating unit that heats the internal air and an air supply device that supplies outside air to the internal space (5). The heating unit may be an internal heat exchanger (15) or an electric heater. Means for reducing the internal pressure (Pi) include a cooling unit that cools the internal air and an exhaust device that discharges the internal air to the outside space (6). The cooling unit may be an internal heat exchanger (15) or a Peltier element or the like. 【0248】 The pressure detection unit does not have to be a differential pressure sensor (170), and may consist only of an internal pressure sensor located in the internal space (5) to detect the internal pressure (Pi). The pressure detection unit may also have both an external pressure sensor located in the external space (6) to detect the external pressure (Po) and an internal pressure sensor. 【0249】 The air processing unit (95) may be configured to separate the outside air (atmosphere) into nitrogen-enriched gas and oxygen-enriched gas using a gas separation membrane. The gas separation membrane has the characteristic that the nitrogen permeation rate is lower than both the oxygen permeation rate and the carbon dioxide permeation rate. Therefore, in the air processing unit (95), the outside air is separated into oxygen-enriched gas that has permeated through the gas separation membrane and nitrogen-enriched gas that has not permeated through the gas separation membrane. 【0250】 The transport container (1) may be a land transport container transported by a truck, railway, or the like. The transport container (1) does not necessarily have to have an air cooling function. 【0251】 The air composition adjustment device (90) may be applied to a stationary storage where fresh fruits and flowers are stored, rather than the storage of the transport container. 【0252】 The controller (110) may be provided in a transport refrigeration device (10), a server device, a terminal device operated by a user, or the like. The controller (110) may be composed of two or more physically separated control elements. 【0253】 Although the embodiments and modification examples have been described above, it will be understood that various changes in form and details are possible without departing from the spirit and scope of the claims. Also, the above embodiments, modification examples, and other embodiments may be appropriately combined or replaced as long as the functions of the objects of the present disclosure are not impaired. 【0254】 The above descriptions of "first", "second", "third", etc. are used to distinguish the clauses to which these descriptions are attached, and do not limit the number or order of those clauses. 【Industrial Applicability】 【0255】 As described above, the present disclosure is useful for an air composition adjustment device and a transport container. 【Explanation of Reference Numerals】 【0256】 2 Container body (storage) 5 Interior space 6 Exterior space 40 Ventilation device (outside air introduction part) 90 Air composition adjustment device 95 Air treatment part 110 Controller 161 Oxygen sensor (concentration sensor) 162 Carbon dioxide sensor (concentration sensor) 170 Differential pressure sensor (pressure detection unit) 231 Air pump (air conveying section, pump, pressure regulating section) 234,235 Adsorption part (adsorption tube) 241 First gas pipe (first flow path) 255 Bypass connecting pipe (third channel) 256 Bypass valve (flow control valve) 272 Gas discharge valve (on / off valve) 275 Gas supply pipe (first channel) 281 Measuring piping (second channel) 291 Auxiliary pump (air conveying section, pump) S supply path

Claims

[Claim 1] A supply path (S) connects the external space (6) and the internal space (5) inside the storage compartment (2), An air processing unit (95) is provided in the supply passage (S) and adjusts the composition of the air, An air transport unit (231, 291) transports the processed gas, whose composition has been adjusted in the air processing unit (95), to the interior space (5) as first air via the supply passage (S), The system includes an air processing unit (95) and a controller (110) that controls the air transport unit (231, 291), The controller (110) performs flow rate control during the operation of the air transport unit (231, 291) to adjust the flow rate of the first air to at least a target flow rate so that the concentration of the components in the air inside the chamber reaches a set value. The controller (110) determines the target flow rate based on the respiration rate of fruits, vegetables or flowers in the storage space (5). Air composition adjustment device. [Claim 2] The controller (110) executes a concentration adjustment mode in which it supplies the first air from the supply path (S) to the interior space (5) in response to an operation command. The controller (110) performs the flow rate control during the concentration adjustment mode. The air composition adjustment device according to claim 1. [Claim 3] The aforementioned air transport unit includes a variable flow rate pump (231, 291), The controller (110) controls the flow rate of the first air by controlling the pumps (231, 291) in the flow rate control. The air composition adjustment device according to claim 1. [Claim 4] The system further includes an outside air introduction unit (40) that introduces outside air from the outside space (6) into the inside space (5) as second air without passing through the supply path (S), The controller (110) adjusts the flow rate of the first air and the flow rate of the second air in the flow rate control so that the concentration of the component in the air inside the chamber reaches the set value. The air composition adjustment device according to claim 1. [Claim 5] The aforementioned outside air intake section (40) includes a ventilation device (40) that supplies the outside air into the interior space (5) of the storage unit. The air composition adjustment device according to claim 4. [Claim 6] The controller (110) performs concentration control during the operation of the air transport unit (231, 291) to adjust the concentration of the components in the first air so that the concentration of the components in the air inside the chamber reaches the set value. The air composition adjustment device according to claim 1. [Claim 7] The air processing unit (95) includes two adsorption units (234, 235) that perform an adsorption operation to adsorb components from the air and a desorption operation to desorb the adsorbed components. A first flow path (244, 275) through which a processed gas whose composition has been adjusted in the adsorption section (234, 235) flows, A second flow path (281) discharges the processing gas from the first flow path (244, 275) to the outside of the chamber, The system further includes an on / off valve (272) provided in the second flow path (281), The controller (110) controls the timing of opening and closing the on-off valve (272) in the concentration control, thereby adjusting the concentration of the components of the first air. The air composition adjustment device according to claim 6. [Claim 8] The air processing unit (95) includes two adsorption units (234, 235) that perform an adsorption operation to adsorb components from the air and a desorption operation to desorb the adsorbed components. A first flow path (244, 275) through which a processed gas whose composition has been adjusted in the adsorption section (234, 235) flows, A third flow path (255) introduces the outside air from the outside space (6) into the first flow path (244, 275) by bypassing the air processing unit (95), The system further includes a flow control valve (256) that adjusts the flow rate of the outside air flowing from the third flow path (255) into the first flow path (244, 275), The controller (110) controls the concentration of the components of the first air by controlling the flow control valve (256) in the concentration control. The air composition adjustment device according to claim 6. [Claim 9] The controller (110) determines the target flow rate to bring the carbon dioxide concentration in the air inside the chamber to the set value, and in the flow rate control, adjusts the flow rate of the first air to the target flow rate. The air composition adjustment device according to claim 1. [Claim 10] A supply passage (S) that connects the external space (6) and the internal space (5) inside the storage compartment (2), An air processing unit (95) is provided in the supply passage (S) and adjusts the composition of the air, An air transport unit (231, 291) transports the processed gas, whose composition has been adjusted in the air processing unit (95), to the interior space (5) as first air via the supply passage (S), The system includes an air processing unit (95) and a controller (110) that controls the air transport unit (231, 291), The controller (110) performs flow rate control during the operation of the air transport unit (231, 291) to adjust the flow rate of the first air so that the concentration of the components in the air inside the chamber reaches a set value. The controller (110) determines a target flow rate to bring the carbon dioxide concentration in the air inside the chamber to the set value, and in the flow rate control, adjusts the flow rate of the first air to the target flow rate. The controller (110) is The carbon dioxide generation rate of fruits, vegetables or flowers in the aforementioned storage space (5) is estimated. The target flow rate is determined based on the estimated carbon dioxide generation rate. Air composition adjustment device. [Claim 11] The controller (110) estimates the carbon dioxide generation rate based on the actual volume of the interior space (5) and the carbon dioxide concentration in the air inside the interior. The air composition adjustment device according to claim 10. [Claim 12] The controller (110) determines a target concentration to bring the oxygen concentration in the air inside the chamber to the set value, and in the concentration control, adjusts the oxygen concentration of the first air to the target concentration. The air composition adjustment device according to claim 6. [Claim 13] A supply passage (S) that connects the external space (6) and the internal space (5) inside the storage compartment (2), An air processing unit (95) is provided in the supply passage (S) and adjusts the composition of the air, An air transport unit (231, 291) transports the processed gas, whose composition has been adjusted in the air processing unit (95), to the interior space (5) as first air via the supply passage (S), The system includes an air processing unit (95) and a controller (110) that controls the air transport unit (231, 291), The controller (110) performs flow rate control during the operation of the air transport unit (231, 291) to adjust the flow rate of the first air so that the concentration of the components in the air inside the chamber reaches a set value. The controller (110) performs concentration control to adjust the concentration of the components in the first air so that the concentration of the components in the air inside the chamber reaches the set value while the air transport unit (231, 291) is in operation. The controller (110) determines a target concentration to bring the oxygen concentration in the air inside the chamber to the set value, and in the concentration control, adjusts the oxygen concentration of the first air to the target concentration. The controller (110) is The oxygen consumption rate of fruits, vegetables or flowers in the aforementioned storage space (5) is estimated. The target concentration is determined based on the oxygen consumption rate. Air composition adjustment device. [Claim 14] The controller (110) estimates the oxygen consumption rate based on the actual volume of the interior space (5) and the oxygen concentration in the air inside the interior. The air composition adjustment device according to claim 13. [Claim 15] A pressure adjustment unit (231) that changes the pressure in the internal space (5) of the chamber, The system further comprises a pressure detection unit (170) for detecting the internal pressure of the internal space (5) of the storage chamber, The controller (110) estimates the actual volume based on a first indicator showing the rate of change of the internal pressure when the internal pressure changes. The air composition adjustment device according to claim 11 or 14. [Claim 16] The chamber further comprises concentration sensors (161, 162) for detecting the carbon dioxide concentration or oxygen concentration in the air inside the chamber, The controller (110) adjusts the flow rate of the first air so that the concentration detected by the concentration sensors (161, 162) reaches the set value in the flow rate control. An air composition adjustment device according to any one of claims 1 to 14. [Claim 17] The chamber further comprises concentration sensors (161, 162) for detecting the carbon dioxide concentration or oxygen concentration in the air inside the chamber, The controller (110) adjusts the concentration of the components of the first air so that the concentration detected by the concentration sensors (161, 162) reaches the set value in the concentration control. An air composition adjustment device according to any one of claims 6 to 8. [Claim 18] A supply passage (S) that connects the external space (6) and the internal space (5) inside the storage compartment (2), An air processing unit (95) is provided in the supply passage (S) and adjusts the composition of the air, An air transport unit (231, 291) transports the processed gas, whose composition has been adjusted in the air processing unit (95), to the interior space (5) as first air via the supply passage (S), The system includes an air processing unit (95) and a controller (110) that controls the air transport unit (231, 291), The controller (110) performs flow rate control during the operation of the air transport unit (231, 291) to adjust the flow rate of the first air so that the concentration of the components in the air inside the chamber reaches a set value. The storage chamber is further equipped with a carbon dioxide sensor (162) for detecting the carbon dioxide concentration in the air inside the chamber. The controller (110) is configured to determine the target flow rate in order to set the carbon dioxide concentration of the air inside the chamber to the set value. The controller (110) is The first flow rate control, which adjusts the flow rate of the first air to the target flow rate, The flow rate of the first air is adjusted so that the carbon dioxide sensor (162) detects the set value, and a second flow rate control is performed as the flow rate control. Air composition adjustment device. [Claim 19] The controller (110) is If the first condition indicating that the carbon dioxide concentration in the air inside the chamber is close to the set value is not met, the first flow rate control is executed. If the first condition is met, the second flow rate control is executed. The air composition adjustment device according to claim 18. [Claim 20] A supply passage (S) that connects the external space (6) and the internal space (5) inside the storage compartment (2), An air processing unit (95) is provided in the supply passage (S) and adjusts the composition of the air, An air transport unit (231, 291) transports the processed gas, whose composition has been adjusted in the air processing unit (95), to the interior space (5) as first air via the supply passage (S), The system includes an air processing unit (95) and a controller (110) that controls the air transport unit (231, 291), The controller (110) performs flow rate control during the operation of the air transport unit (231, 291) to adjust the flow rate of the first air so that the concentration of the components in the air inside the chamber reaches a set value. The controller (110) performs concentration control to adjust the concentration of the components in the first air so that the concentration of the components in the air inside the chamber reaches the set value while the air transport unit (231, 291) is in operation. The chamber is equipped with an oxygen sensor (161) for detecting the oxygen concentration in the air inside the chamber. The controller (110) is configured to determine a target concentration for bringing the oxygen concentration of the air inside the chamber to the set value. The controller (110) is The first concentration control, which adjusts the oxygen concentration of the first air to the target concentration, The oxygen concentration of the first air is adjusted so that the concentration detected by the oxygen sensor (161) reaches the set value, and a second concentration control is performed as the concentration control. Air composition adjustment device. [Claim 21] The controller (110) executes the first concentration control when the second condition indicating that the oxygen concentration in the air inside the chamber is close to the set value is not met. If the second condition is met, the second concentration control is executed. The air composition adjustment device according to claim 20. [Claim 22] A transport container comprising an air composition adjustment device (90) according to any one of claims 1 to 14.

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