Container refrigeration equipment

Abstract

To restrain change of temperature of air in a container due to a ventilation operation.SOLUTION: A control part adjusts a cooling ability of a cooling unit 10A based on a ventilation cooling load which is a cooling load accompanied with a ventilation operation of a ventilation device 40. The control part controls the ventilation device so that a ventilation amount of the ventilation device approaches to a first ventilation amount, and adjusts the cooling ability of the cooling unit based on an indoor cooling load which is a cooling load in a container, and the ventilation cooling load corresponding to the first ventilation amount.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a container refrigeration system. [Background technology]

[0002] Patent Document 1 discloses a container refrigeration unit. The container refrigeration unit is applied to a container for transporting objects such as food, and performs a cooling operation to cool the interior of the container. Paragraph 0099 of Patent Document 1 discloses that when the temperature inside the container reaches a predetermined temperature through the cooling operation, the compressor stops and a ventilation device operates to introduce outside air into the container. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4609590 Summary of the Invention [Problem to be solved by the invention]

[0004] In the container refrigeration unit of Patent Document 1, a ventilation device performs a ventilation operation to supply outside air into the refrigerator. When the ventilation operation is performed, the temperature of the inside air changes due to the outside air being introduced into the refrigerator. As a result, the temperature control of the target items is impaired.

[0005] The present disclosure aims to suppress changes in the temperature of the air inside a refrigerator caused by ventilation operations. [Means for solving the problem]

[0006] The first aspect is a container refrigeration system. The container refrigeration system includes a cooling unit (10A) having a compressor (25), a radiator (26), an expansion mechanism (31), and an evaporator (29), and performing a cooling operation to cool the interior of the container (1) using the evaporator (29), a ventilation device (40) that supplies outside air to the interior of the container (1), and a control unit (100) that controls the cooling unit (10A) and the ventilation device (40). The control unit (100) adjusts the cooling capacity of the cooling unit (10A) based on a ventilation cooling load associated with the ventilation operation of the ventilation device (40).

[0007] In the first aspect, the control unit (100) adjusts the cooling capacity of the cooling unit (10A) based on the ventilation cooling load caused by the ventilation operation of the ventilation device (40). Therefore, when the cooling load of the cooling unit (10A) increases due to the ventilation operation, the cooling capacity increases in accordance with the cooling load. As a result, it is possible to prevent the temperature of the air inside the refrigerator from changing due to the ventilation operation.

[0008] In the second aspect, the control unit (100) controls the ventilation device (40) so that the ventilation rate of the ventilation device (40) approaches the first ventilation rate. The control unit (100) adjusts the cooling capacity of the cooling unit (10A) based on the interior cooling load, which is the cooling load inside the cabinet, and the ventilation cooling load corresponding to the first ventilation rate.

[0009] In the second aspect, the ventilation device (40) performs ventilation operation with a first ventilation rate as a target value. The control unit (100) of the cooling unit (10A) adjusts the cooling capacity of the cooling unit (10A) based on the ventilation cooling load corresponding to the first ventilation rate as well as the internal cooling load, which is the cooling load inside the storage compartment. This makes it possible to prevent changes in the temperature of the internal air caused by changes in the ventilation rate of the ventilation device (40) up to the first ventilation rate.

[0010] In the third aspect, in the second aspect, the control unit (100) executes a first control for determining a first cooling capacity of the cooling unit (10A) based on the inside cooling load and the ventilation cooling load corresponding to the first ventilation rate, a second control for bringing the ventilation rate of the ventilation device (40) closer to the first ventilation rate after the first control, and a third control for bringing the cooling capacity of the cooling unit (10A) closer to the first cooling capacity after the first control.

[0011] In the third aspect, in the first control, the first cooling capacity is determined based on the inside cooling load and the ventilation cooling load corresponding to the first ventilation rate. In the second control following the first control, the ventilation rate of the ventilation device (40) approaches the first ventilation rate. In addition, in the third control following the first control, the cooling capacity approaches the first cooling capacity. As a result, when the ventilation rate of the ventilation device (40) reaches the first ventilation rate, the cooling capacity is likely to already reach the first cooling capacity. This makes it possible to suppress changes in the temperature of the inside air caused by the ventilation rate of the ventilation device (40) changing to the first ventilation rate.

[0012] In a fourth aspect, in any one of the first to third aspects, the control unit (100) performs a first limiting operation to limit the rate of change in the ventilation rate of the ventilation device (40) so that an index indicating the rate of change in the cooling capacity of the cooling unit (10A) accompanying the ventilation operation of the ventilation device (40) becomes equal to or less than a predetermined value.

[0013] If the first cooling load changes significantly due to the ventilation operation of the ventilation device (40), the rate of change of the cooling capacity of the cooling unit (10A) may exceed a limited range, and changes in the temperature of the inside air may not be suppressed. Therefore, the control unit (100) limits the rate of change of the ventilation volume of the ventilation device (40) so that an index indicating a rate of change in the cooling capacity of the cooling unit (10A) due to the ventilation operation of the ventilation device (40) is equal to or less than a predetermined value. This prevents the cooling capacity of the cooling unit (10A) from being unable to follow changes in the second cooling load due to the ventilation operation. As a result, changes in the temperature of the inside air can be suppressed.

[0014] In a fifth aspect, in the fourth aspect, the control unit (100) executes a first limiting operation when a first mode is selected by operating the operation unit (110).

[0015] In the fifth aspect, the user or the like can select whether or not to perform the first restricting operation by operating the operation unit (110).

[0016] A sixth aspect is any one of the first to fifth aspects, wherein the control unit (100) controls the ventilation device (40) based on the cooling capacity of the cooling unit (10A).

[0017] In a sixth embodiment, the ventilation device (40) is controlled based on the cooling capacity of the cooling unit (10A).

[0018] In a seventh aspect, in the sixth aspect, the control unit (100) performs a second limiting operation to limit the ventilation rate of the ventilation device (40) when the index indicating the cooling capacity of the cooling unit (10A) is greater than a predetermined value.

[0019] In the seventh aspect, when the cooling capacity of the cooling unit (10A) is high, the ventilation volume of the ventilation device (40) is limited, thereby preventing the cooling unit (10A) from being unable to process the second cooling load associated with the ventilation operation.

[0020] In the eighth aspect, when the second mode is selected by operating the operating section (110) in the seventh aspect, the second limiting operation is performed.

[0021] In the eighth aspect, the user or the like can select whether or not to perform the second restricting operation by operating the operation unit (110). [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 is a perspective view of a container refrigeration unit according to an embodiment, as seen from the front. [Figure 2] FIG. 2 is a vertical cross-sectional view of a container refrigeration unit. [Figure 3] FIG. 3 is a piping diagram of a container refrigeration unit. [Figure 4] Figure 4 is a schematic front view of the ventilation device, with Figure 4(A) showing the lid in the closed position, Figure 4(B) showing the lid in the intermediate position, and Figure 4(C) showing the lid in the fully open position. [Figure 5] FIG. 5 is a block diagram of the main components of the container refrigeration system. [Figure 6] FIG. 6 is a flowchart for explaining switching between the normal mode, the ventilation load suppression mode, and the cooling priority mode of the cooling operation. [Figure 7] FIG. 7 is a flowchart for explaining the control in the normal mode. [Figure 8] FIG. 8 is a flowchart for explaining the control of the ventilation load suppression mode. [Figure 9] FIG. 9 is a flowchart for explaining the control in the cooling priority mode. DETAILED DESCRIPTION OF THE INVENTION

[0023] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the embodiments shown below, and various modifications are possible within the scope of the technical concept of the present disclosure. Since the drawings are intended to conceptually explain the present disclosure, dimensions, ratios, or numbers may be exaggerated or simplified as necessary to facilitate understanding.

[0024] (1) Overall configuration of container refrigeration unit The container refrigeration unit 10 will now be described. In the following description, terms such as "front," "rear," "up," "down," "right," and "left" are based on the directions indicated by the arrows in FIG.

[0025] As shown in Figures 1 and 2, the container refrigeration unit (10) is provided in a container (1). The container (1) is used for marine transportation. The container (1) is a refrigerated container that cools the air inside the container (1). The container (1) has a container body (2) and a container refrigeration unit (10). The container body (2) stores objects such as food and plants. The container refrigeration unit (10) cools the air in an interior space (3) of the container body (2). As shown in Figure 2, a front opening (4) is formed in the front of the container body (2). The container refrigeration unit (10) is attached to the container body (2) so as to close the front opening (4) of the container body (2).

[0026] As shown in FIG. 5, the container refrigeration system (10) includes a cooling unit (10A) for cooling the interior space (3) and a ventilation device (40) for ventilating the interior space (3).

[0027] (2) Cooling unit As shown in FIGS. 1 and 2, the cooling unit (10A) has a casing (11). The casing (11) forms a lid for the front opening (4) of the container body (2). The casing (11) has a casing main body (12) and a partition plate (13). The casing main body (12) separates the container body (2) into an external space (5), which is an external space, and the internal space (3). The partition plate (13) is located on the back side (rear side) of the casing (11).

[0028] The cooling unit (10A) includes, as components arranged outside the refrigerator, a compressor (25), an external heat exchanger (26), and an external fan (27). The cooling unit (10A) includes, as components arranged inside the refrigerator, an internal heat exchanger (29) and an internal fan (30).

[0029] (2-1) Casing body As shown in Fig. 2, the casing body (12) has a flat plate portion (12a) and a recessed portion (12b). The flat plate portion (12a) is formed on the upper part of the casing body (12) so as to be substantially flush with the front opening (4) of the casing (11). As shown in Fig. 1, the flat plate portion (12a) is provided with an inspection window (22). The inspection window (22) is located on the right side of the flat plate portion (12a). The inspection window (22) is a transparent window through which the inside of the casing body (12) can be seen.

[0030] The recess (12b) is formed in the lower part of the casing (11). The recess (12b) is recessed rearward from the lower end of the flat plate portion (12a). An external storage space (14) is formed in front of the recess (12b). An internal storage space (15) is formed above the recess (12b) and between the flat plate portion (12a) and the partition plate (13). The lower end of the recess (12b) forms a bottom plate (12c). The bottom plate (12c) extends to both the left and right ends of the casing body (12).

[0031] The casing body (12) is formed by laminating an external casing (16), a heat insulating layer (17), and an internal casing (18) in the thickness direction (front-rear direction). The external casing (16) faces the external space (5). The internal casing (18) faces the interior of the refrigerator. The heat insulating layer (17) is provided between the external casing (16) and the internal casing (18). The external casing (16) is made of aluminum material. The internal casing (18) is made of fiber-reinforced plastic (FRP). The heat insulating layer (17) is made of foamed resin.

[0032] (2-2) Partition plate and air passage As shown in FIG. 2, the partition plate (13) is a plate-like member located on the rear side of the recessed portion (12b). The partition plate (13) extends in the vertical direction so as to be spaced a predetermined distance from the rear surface of the recessed portion (12b). An internal passage (19) through which internal air flows is formed between the casing body (12) and the partition plate (13). An inlet (20) is formed between the upper end of the partition plate (13) and the upper wall (2a) of the container body (2). The inlet (20) connects the internal space (3) with the inlet end of the internal passage (19). An outlet (21) is formed between the lower end of the partition plate (13) and the lower wall (2b) of the container body (2). The outlet (21) connects the internal space (3) with the outlet end of the internal passage (19).

[0033] (2-3) Equipment in the external space The external storage space (14) is provided with a compressor (25), an external heat exchanger (26), and an external fan (27). The compressor (25) is installed on the bottom plate (12c) of the casing (11). The compressor (25) is disposed near the bottom of the external storage space (14). The compressor (25) is disposed near the right of the external storage space (14).

[0034] The external fan (27) is located near the upper part of the external storage space (14). The external fan (27) is a propeller fan. As shown in FIG. 2, an external passage (28) through which outside air flows is formed behind the external fan (27).

[0035] The external heat exchanger (26) is provided in the external storage space (14) at a height position between the external fan (27) and the compressor (25). The external heat exchanger (26) is located in the external passage (28). The external heat exchanger (26) is a fin-and-tube heat exchanger.

[0036] (2-4) Equipment in the storage space An internal heat exchanger (29) and an internal fan (30) are provided in the internal storage space (15). The internal heat exchanger (29) is supported by the casing (11) so as to span the casing body (12) and the partition plate (13). The internal heat exchanger (29) is a fin-and-tube heat exchanger.

[0037] (2-5) Refrigerant circuit As shown in FIG. 3, the cooling unit (10A) has a refrigerant circuit (R). The refrigerant circuit (R) is filled with a refrigerant. The refrigerant circuit (R) performs a vapor compression refrigeration cycle by circulating the refrigerant. The refrigerant circuit (R) uses, for example, natural refrigerants such as propane and carbon dioxide.

[0038] The refrigerant circuit (R) mainly includes a compressor (25), an external heat exchanger (26), an expansion valve (31), and an internal heat exchanger (29).

[0039] The compressor (25) compresses the drawn refrigerant. The compressor (25) discharges the compressed refrigerant. A discharge pipe (32) is connected to a discharge portion of the compressor (25). A suction pipe (33) is connected to a suction portion of the compressor (25). An accumulator (34) is provided in the suction pipe (33). The accumulator (34) is a container for storing liquid refrigerant.

[0040] The external heat exchanger (26) exchanges heat between the refrigerant flowing therethrough and the external air. The gas end of the external heat exchanger (26) communicates with the discharge pipe (32). The liquid end of the external heat exchanger (26) is connected to the liquid end of the internal heat exchanger (29) via a liquid pipe (35). The external heat exchanger (26) functions as a radiator (condenser) that radiates heat from the refrigerant to the air.

[0041] The expansion valve (31) is provided in the liquid pipe (35). The expansion valve (31) is an expansion mechanism that reduces the pressure of high-pressure refrigerant to low-pressure refrigerant. The expansion valve (31) is an electronic expansion valve with an adjustable opening. The expansion mechanism may be a capillary tube or an expander. A receiver (36) is provided in the liquid pipe (35) between the external heat exchanger (26) and the expansion valve (31). The receiver (36) is a container that stores excess refrigerant in the refrigerant circuit (R).

[0042] The internal heat exchanger (29) exchanges heat between the refrigerant flowing therethrough and the internal air. The gas end of the internal heat exchanger (29) communicates with the suction pipe (33). The internal heat exchanger (29) functions as an evaporator in which the refrigerant absorbs heat from the air.

[0043] The refrigerant circuit (R) has a bypass pipe (37). An inflow end of the bypass pipe (37) communicates with the discharge pipe (32), and an outflow end of the bypass pipe (37) communicates with the liquid pipe (35). The bypass pipe (37) sends the refrigerant discharged from the compressor (25) to the internal heat exchanger (29), bypassing the external heat exchanger (26).

[0044] The refrigerant circuit (R) is provided with a first valve (38) and a second valve (39). The first valve (38) is provided between the discharge side of the compressor (25) and the gas end of the external heat exchanger (26), and downstream of the connection portion of the bypass pipe (37). The second valve (39) is provided in the bypass pipe (37). The first valve (38) and the second valve (39) are formed by solenoid on-off valves. The first valve (38) and the second valve (39) may be flow control valves whose opening degrees are adjustable.

[0045] (3) Ventilation equipment The configuration of the ventilation device (40) will be described with reference to Figures 1, 2, and 4. The ventilation device (40) ventilates the interior space (3) of the container body (2). The ventilation device (40) of this embodiment has an air supply function of supplying outside air, which is outdoor air, to the interior space (3) and an exhaust function of discharging the interior air to the exterior space (5).

[0046] As shown in Fig. 1, the ventilation device (40) is disposed in a left-side portion of the flat plate portion (12a) of the casing body (12). As shown in Fig. 2, the ventilation device (40) is provided in a ventilation mounting opening (6) formed in the front surface of the casing body (12). The ventilation mounting opening (6) penetrates the casing body (12) from front to rear. The ventilation mounting opening (6) is formed through the exterior casing (16), the heat insulating layer (17), and the interior casing (18).

[0047] 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) communicate between the internal space (3) and the external space (5). Specifically, the inflow end of the air supply passage (41) communicates with the external space (5). The outflow end of the air supply passage (41) communicates with the primary side (upstream side) of the internal fan (30) in the internal passage (19). The inflow end of the exhaust passage (42) communicates with the secondary side (downstream side) of the internal fan (30) in the internal passage (19). The outflow end of the exhaust passage (42) communicates with the external space (5).

[0048] The ventilation device (40) has a ventilation fan. The ventilation fan is configured by the above-described internal fan (30). In this embodiment, the internal fan (30) serves both as the ventilation device (40) and the cooling unit (10A). When the internal fan (30) is driven, outside air from the external space (5) is supplied to the internal space (3) through the air supply passage (41). At the same time, inside air from the internal space (3) is discharged to the external space (5) through the air exhaust passage (42).

[0049] 2 and 4, an air supply communication port (41a) is formed at an end of the air supply passage (41) on the side of the external space (5). An air exhaust communication port (42a) is formed at an end of the air exhaust passage (42) on the side of the external space (5).

[0050] As shown in FIG. 2, the ventilation device (40) includes a motor (43), a drive shaft (44) that is rotationally driven by the motor (43), and an open / close lid (45) that is connected to the drive shaft (44). The motor (43) and the drive shaft (44) are housed in a casing of the ventilation device (40). The motor (43) is a stepping motor. The drive shaft (44) is directly connected to the motor (43). The drive shaft (44) may also be indirectly connected to the motor (43) via a pinion or gear.

[0051] The open-close lid (45) is provided in front of the drive shaft (44). The open-close lid (45) is configured to be rotatable about the axis of the drive shaft (44). The open-close lid (45) opens and closes the air supply passage (41) and the exhaust passage (42) depending on the angle of rotation of the open-close lid (45). The open-close lid (45) constitutes an opening adjustment mechanism that adjusts the opening degrees of the air supply passage (41) and the exhaust passage (42).

[0052] 4, the open / close cover (45) is formed with an air intake opening (46) and an exhaust opening (47). The air intake opening (46) is configured to be able to communicate with the air intake communication port (41 a). The exhaust opening (47) is configured to be able to communicate with the exhaust communication port (42 a).

[0053] Specifically, when the open-close lid (45) is at the first rotation angle (closed position) shown in Fig. 4(A), the air supply communication opening (41a) is entirely covered by the open-close lid (45), and the exhaust communication opening (42a) is entirely covered by the open-close lid (45). As a result, the air supply passage (41) and the exhaust passage (42) are fully closed.

[0054] When the open-close cover (45) is at the second rotation angle (fully open position) shown in Fig. 4(C), the entire air supply communication port (41a) overlaps with the air supply opening (46), and the entire air exhaust communication port (42a) overlaps with the air exhaust opening (47). As a result, the air supply passage (41) and the air exhaust passage (42) are fully open.

[0055] When the open-close cover (45) is at the third rotation angle (intermediate position) shown in Fig. 4(B), a portion of the air supply communication port (41a) overlaps with the air supply opening (46) in the axial direction, and a portion of the exhaust communication port (42a) overlaps with the exhaust opening (47) in the axial direction. The intermediate position is a position between the closed position and the fully open position. Therefore, the opening degrees of the air supply passage (41) and the exhaust passage (42) are smaller than in the fully open state.

[0056] By adjusting the rotation angle of the opening / closing lid (45) between the closed position and the fully open position, the opening degrees of the air supply passage (41) and the air exhaust passage (42) are adjusted, and further, the ventilation volume of the ventilation device (40) is adjusted.

[0057] (4) Sensor The container refrigeration system (10) has a plurality of sensors, including an inside temperature sensor (51), an outside temperature sensor (52), and an oxygen concentration sensor (53), as shown in Figures 2 and 5.

[0058] The internal temperature sensor (51) detects the temperature of the internal air in the container (1) (hereinafter also referred to as the internal temperature (Ti)). The internal temperature sensor (51) is arranged in the internal passage (19) upstream of the internal fan (30) in the air flow direction. The internal temperature sensor (51) is arranged near the inlet (20) of the internal passage (19).

[0059] The outside-compartment temperature sensor (52) detects the temperature of the outside air outside the container (1) (hereinafter also referred to as the outside-compartment temperature (To)). The outside-compartment temperature sensor (52) is arranged in the external passage (28) upstream of the external heat exchanger (26) in the air flow direction. The outside-compartment temperature sensor (52) is arranged near the inlet of the external passage (28).

[0060] The oxygen concentration sensor (53) is an air quality sensor that detects the concentration of components in the interior air. The oxygen concentration sensor (53) detects the oxygen concentration in the interior air. The oxygen concentration sensor (53) is arranged in the internal passage (19) upstream of the interior fan (30) in the air flow direction. The oxygen concentration sensor (53) is arranged near the inlet (20) of the internal passage (19).

[0061] As shown in Figures 3 and 5, the plurality of sensors includes a high-pressure pressure sensor (54), a low-pressure pressure sensor (55), and an intake temperature sensor (56). The high-pressure pressure sensor (54) is provided in a high-pressure line of the refrigerant circuit (R), for example, in the discharge pipe (32) of the compressor (25). The high-pressure pressure sensor (54) detects the pressure of the high-pressure refrigerant in the refrigerant circuit (R). The low-pressure pressure sensor (55) is provided in a low-pressure line of the refrigerant circuit (R), for example, in the suction pipe (33) of the compressor (25). The low-pressure pressure sensor (55) detects the pressure of the low-pressure refrigerant in the refrigerant circuit (R). The suction temperature sensor (56) detects the temperature of the refrigerant sucked into the compressor (25).

[0062] (5) Control unit and operation unit As shown in FIG. 5, the container refrigeration system (10) has a control unit (100). The control unit (100) controls the cooling unit (10A) and the ventilation system (40). The control unit (100) includes a microprocessor, an electric circuit, and an electronic circuit. The microprocessor includes a CPU (Central Processing Unit), a memory, a communication interface, an analog input / output, and a contact input / output interface. The memory stores various programs to be executed by the CPU and data used by the programs.

[0063] The control unit (100) controls each component of the cooling unit (10A). Specifically, the control unit (100) controls the rotation speed of the compressor (25), the rotation speed of the internal fan (30), the rotation speed of the external fan (27), the opening of the expansion valve (31), etc. The control unit (100) controls the motor (43) of the ventilation device (40). The control unit (100) adjusts the opening of the air supply passage (41) and the air exhaust passage (42) of the ventilation device (40), and further adjusts the ventilation volume of the ventilation device (40).

[0064] As shown in FIG. 5, the container refrigeration unit (10) has an operation unit (110). The operation unit (110) is configured with, for example, a touch panel, a remote controller, a switch, or the like provided in the container refrigeration unit (10). The operation unit (110) may be a communication terminal connected to the container refrigeration unit (10) via a network. A user can operate the operation unit (110) to switch the operation mode of the container refrigeration unit (10) or change the set values of each operation mode. The set values include a target temperature of the interior space (3).

[0065] (6) Driving behavior The container refrigeration system (10) performs a cooling operation and a defrosting operation. The cooling operation is an operation mode that is executed by a user or the like operating the operation unit (110).

[0066] During the cooling operation, a refrigeration cycle is performed in which refrigerant compressed by the compressor (25) is condensed in the external heat exchanger (26), reduced in pressure by the expansion valve (31), and evaporated in the internal heat exchanger (29). Air flowing out from the internal space (3) into the internal passage (19) is cooled by the internal heat exchanger (29) functioning as an evaporator. The cooled air is sent to the internal space (3).

[0067] In the cooling operation, the control unit (100) basically controls the rotation speed of the compressor (25) based on the difference between the temperature of the air in the internal space (3) and a target temperature. In the cooling operation, the control unit (100) basically controls the opening of the expansion valve (31) based on the suction superheat of the refrigerant circuit (R). The suction superheat is determined by the difference between the saturation temperature corresponding to the low pressure detected by the low-pressure pressure sensor (55) and the refrigerant temperature detected by the suction temperature sensor (56).

[0068] During the defrosting operation, the refrigerant compressed by the compressor (25) flows through the bypass pipe (37) and then through the internal heat exchanger (29). The frost on the surface of the internal heat exchanger (29) melts due to the heat of the refrigerant flowing through the internal heat exchanger (29).

[0069] (7) Control of ventilation during cooling operation (7-1) Overview In the cooling operation described above, the interior of the container (1) is cooled by the internal heat exchanger (29), which serves as an evaporator. During the cooling operation, when the ventilation device (40) performs a ventilation operation to supply outside air into the container, the temperature of the inside air changes due to the influence of heat input from the outside air. As a result, the temperature of the object cannot be maintained at a desired temperature. Therefore, the container refrigeration system (10) of this embodiment adjusts the cooling capacity of the cooling unit (10A) based on the ventilation cooling load associated with the ventilation operation. Specifically, the control unit (100) adjusts the cooling capacity based on the internal cooling load and the ventilation cooling load. Here, the internal cooling load is the current internal cooling load. The ventilation cooling load is a cooling load that changes with the operation of the ventilation device (40). If the ventilation rate of the ventilation device (40) increases, the ventilation cooling load increases, and if the ventilation rate of the ventilation device (40) decreases, the ventilation cooling load decreases.

[0070] (7-2) Switching between modes The switching between the modes of the cooling operation will now be described. The user can select a normal mode, a first mode (ventilation load reduction mode), or a second mode (cooling priority mode) by operating the operation unit (110). The normal mode is a mode in which ventilation takes priority over cooling the refrigerator interior. The ventilation load reduction mode is a mode in which changes in the ventilation / cooling load are suppressed. The cooling priority mode is a mode in which cooling the refrigerator interior takes priority over ventilation.

[0071] 6, when a command to start the cooling operation is input to the control unit (100) in step S11, the cooling operation is started in step S12. In step S13, if the ventilation load reduction mode is selected by operating the operation unit (110), a first command to execute the ventilation load reduction mode is output from the operation unit (110) to the control unit (100). The control unit (100), to which the first command is input, executes the ventilation load reduction mode in step S17.

[0072] In step S14, if the cooling priority mode is selected by operation of the operation unit (110), a second command is output from the operation unit (110) to the control unit (100). The control unit (100), to which the second command has been input, executes the cooling priority mode in step S16. If the ventilation load reduction mode has not been selected in step S13 and the cooling priority mode has not been selected in step S14, a third command is output from the operation unit (110) to the control unit (100) to execute the normal mode. The control unit (100), to which the third command has been input, executes the normal mode in step S15.

[0073] In step S18, a command to end the cooling operation is input to the control unit (100), and in step S19, the cooling operation is ended.

[0074] (7-3) Normal mode The normal mode will be described with reference to FIG.

[0075] When the normal mode starts, in step S21, the control unit (100) determines a target ventilation rate (Vt) (first ventilation rate) of the ventilation device (40) based on the current oxygen concentration (Ci) of the air inside the container and the target oxygen concentration (Ct). Here, the current oxygen concentration (Ci) of the air inside the container is detected by the oxygen concentration sensor (53). The target oxygen concentration (Ct) is set by a user operating the operation unit (110) depending on the type of object stored in the container (1), the storage period, etc. If the current oxygen concentration (Co) is lower than the target oxygen concentration (Ct), the target ventilation rate (Vt) of the ventilation device (40) is increased. If the current oxygen concentration (Ci) is higher than the target oxygen concentration (Ct), the target ventilation rate (Vt) becomes zero.

[0076] The control unit (100) determines the target ventilation volume (Vt) using the following equation (1):

[0077] Vt=(Ct-Ci)×A / (t1×Co)···(1) formula Here, Ct is the target oxygen concentration [%], Ci is the current oxygen concentration [%] of the inside air, A is the volume of the inside space (3) in the container (1), t1 is the execution time [h] of the ventilation operation for converging the oxygen concentration to the target oxygen concentration, and Co is the oxygen concentration [%] of the outside air. The volume (A) of the inside space (3) is set by a user or the like operating the operation unit (110). The oxygen concentration (Co) of the outside air is set to, for example, 21%.

[0078] Next, in step S22, the control unit (100) predicts a ventilation cooling load (L1) corresponding to the target ventilation rate (Vt) calculated in step S21. In this embodiment, the ventilation cooling load (L1) corresponds to a sensible heat load imparted to the interior space (3) by the ventilation operation of the ventilation device (40). The control unit (100) calculates the ventilation cooling load (L1) using the following equation (2):

[0079] L1=α×Vt×(To-Ti)...Equation (2) Here, L1 is the ventilation cooling load [W], which corresponds to the sensible heat load (Ls) associated with ventilation in this example. Vt is the target ventilation volume [m 3 / h], and α is a coefficient (for example, 0.33) taking into account the specific heat and density of air. To is the temperature of the air outside the cabinet (hereinafter also referred to as the outside cabinet temperature) [°C], and Ti is the temperature of the air inside the cabinet (hereinafter also referred to as the inside cabinet temperature) [°C]. The outside cabinet temperature (To) is detected by the outside cabinet temperature sensor (52). The inside cabinet temperature (Ti) is detected by the inside cabinet temperature sensor (51).

[0080] In step S23, the control unit (100) estimates the internal cooling load (L2). The internal cooling load (L2) [W] corresponds to the current cooling capacity of the cooling unit (10A). The internal cooling load (L2) is calculated from the current rotation speed of the compressor (25), the high-pressure pressure of the refrigerant circuit (R), and the low-pressure pressure of the refrigerant circuit (R). The current rotation speed of the compressor (25) is determined by the temperature difference between the internal temperature (Ti) and the target temperature (Ts) of the internal space (3). As the temperature difference increases, the target evaporation temperature of the internal heat exchanger (29) decreases, which in turn increases the rotation speed of the compressor (25). As the temperature difference decreases, the target evaporation temperature of the internal heat exchanger (29) increases, which in turn decreases the rotation speed of the compressor (25). The high-pressure pressure is detected by the high-pressure pressure sensor (54). The low pressure is detected by a low pressure sensor (55).

[0081] The control unit (100) estimates the internal cooling load (L2) from the performance characteristics of the compressor (25) based on the current rotation speed of the compressor (25), the high-pressure pressure, and the low-pressure pressure. The control unit (100) may estimate the internal cooling load (L2) using a function or a table.

[0082] The control unit (100) may execute the process of step S23 before the process of step S22.

[0083] In step S24, the control unit (100) determines a target cooling capacity (first cooling capacity) of the cooling unit (10A) based on the ventilation cooling load (L1) determined in step S22 and the inside cooling load (L2) estimated in step S23. The process in step S24 corresponds to the first control. Specifically, the control unit (100) determines the target rotation speed (Nt) [rps] of the compressor (25) using the following equation (3):

[0084] Nt = Nc × (L1 + L2) / L2 (3) Here, Nc is the current rotation speed [rps] of the compressor (25).

[0085] According to equation (3), as the target ventilation rate (Vt) of the ventilation device (40) and further the ventilation cooling load (L1) increase, the target rotation speed (Nt) of the compressor (25) increases. As the target ventilation rate (Vt) of the ventilation device (40) and further the ventilation cooling load (L1) decrease, the target rotation speed (Nt) of the compressor (25) decreases.

[0086] Next, in step S25, the ventilation device (40) is controlled so that the current ventilation volume of the ventilation device (40) approaches the target ventilation volume (Vt). The process of step S25 corresponds to the second control. If the target ventilation volume (Vt) is large, the opening of the ventilation port (VO) of the ventilation device (40) is increased, and the ventilation volume increases. If the target ventilation volume (Vt) is small, the opening of the ventilation port (VO) of the ventilation device (40) is decreased, and the ventilation volume decreases. If the target ventilation volume (Vt) is zero, the ventilation port (VO) of the ventilation device (40) is fully closed, and the ventilation volume becomes zero.

[0087] In step S26, the control unit (100) controls the cooling unit (10A) so that the cooling capacity of the cooling unit (10A) approaches the first cooling capacity. The process in step S26 corresponds to the third control. The first cooling capacity corresponds to the sum of the inside cooling load and the ventilation cooling load. Specifically, the control unit (100) controls the compressor (25) so that the rotation speed of the compressor (25) approaches the target rotation speed (Nt) determined in step S25.

[0088] In this manner, the control unit (100) of this embodiment determines the rotation speed of the compressor (25), and therefore the cooling capacity of the cooling unit (10A), based on the ventilation cooling load (L1) in addition to the current internal cooling load (L2). In other words, the control unit (100) performs feedforward control using the ventilation cooling load (L1) corresponding to the target ventilation rate (Vt) of the ventilation device (40) as a control index. Therefore, when the ventilation rate of the ventilation device (40) reaches the target ventilation rate (Vt), the cooling capacity of the cooling unit (10A) approaches the cooling capacity capable of processing the ventilation cooling load (L1). As a result, it is possible to prevent the internal air temperature of the internal space (3) from changing significantly due to the ventilation operation of the ventilation device (40). As a result, it is possible to prevent the temperature of the target object from being poorly controlled.

[0089] The control unit (100) may start the second control in step S25 and the third control in step S26 simultaneously, or may start the third control in step S26 before the second control in step S25.

[0090] (7-4) Ventilation load suppression mode As described above, in the normal mode, the cooling capacity of the cooling unit (10A) is determined based on the ventilation cooling load. On the other hand, in the normal mode, if the ventilation rate of the ventilation device (40) changes significantly, the cooling capacity of the cooling unit (10A) may not be able to adequately keep up with the change. Specifically, in the normal mode, if there is a large difference between the target rotation speed of the compressor (25) calculated by equation (3) and the current rotation speed of the compressor (25), the third control in step S26 increases the rate of change of the rotation speed of the compressor (25). Here, the rate of change refers to the amount of change of the compressor over a predetermined period. If the rate of change of the rotation speed of the compressor (25) exceeds a predetermined limit, the compressor (25) may not be adequately controlled or may cause a breakdown of the compressor (25) or other devices. Therefore, in the ventilation load reduction mode, such a problem is resolved by suppressing the fluctuation of the ventilation cooling load.

[0091] The ventilation load reduction mode will be described in detail with reference to FIG.

[0092] When the ventilation load reduction mode starts, the processes of steps S31 to S34 are executed. These processes are the same as the processes of steps S21 to S24 in the normal mode, so a detailed description thereof will be omitted.

[0093] Next, in step S35, the control section (100) determines whether the absolute value of the difference between the rotation speed of the compressor (25) and the target rotation speed of the compressor (25) is greater than a first value. This absolute value is an index indicating the rate of change in the cooling capacity of the cooling unit (10A). The first value is a limit value for the rate of change in the rotation speed of the compressor (25).

[0094] If the absolute value of the difference between the target rotation speed (Nt) and the current rotation speed (Nc) is smaller than the first value, the process proceeds to normal operation in steps S36 and S37. In this case, the control unit (100) does not limit the ventilation rate of the ventilation device (40). In step S36, the control unit (100) controls the ventilation device (40) so that the ventilation rate approaches the target ventilation rate (Vt). In step S37, the control unit (100) controls the cooling unit (10A) so that the cooling capacity of the cooling unit (10A) approaches the target cooling capacity, specifically, so that the rotation speed of the compressor (25) approaches the target rotation speed (Nt). In normal operation, the rate of change of the rotation speed of the compressor (25) is smaller than the first value, and therefore the above-mentioned problem does not occur.

[0095] If the absolute value of the difference between the target rotation speed (Nt) and the current rotation speed (Nc) is greater than the first value, the process proceeds to the first limiting operation of steps S41 to S45.

[0096] In step S41, the control unit (100) determines the restricted ventilation volume (Vl). The restricted ventilation volume (Vl) is a ventilation volume for preventing the rate of change (the above-mentioned absolute value) of the rotation speed (Nc) of the compressor (25) from exceeding a first value. In step S41, the control unit (100) determines the restricted ventilation volume (Vl) in the following manner.

[0097] In step S41, first, the control section (100) calculates the cooling capacity limit change amount (ΔW) using equation (4).

[0098] Cooling capacity limit change amount (ΔW) = R2 / Rc × L2-L2 (4) The cooling capacity limit change amount (ΔW) is the amount of change in cooling capacity obtained when the rotational speed of the compressor (25) is limited by a limit width (ΔR1) [rps]. R2 is the limit rotational speed [rps] after the current rotational speed of the compressor (25) is changed by the limit width (ΔR1) during the operating time (t2). The limit width (ΔR1) is the fluctuation width [rps] of the rotational speed of the compressor (25) that can be controlled during the operating time (t2). ΔR1 is set to, for example, 5 [rps], and the operating time (t2) is set to, for example, 20 seconds. If the current ventilation volume is smaller than the target ventilation volume (Vt), the ventilation volume of the ventilation device (40) increases, and therefore the rotational speed of the compressor (25) needs to be increased. Therefore, if the current ventilation volume is smaller than the target ventilation volume (Vt), the limit rotational speed (R2) is equal to the current rotational speed (Nc) of the compressor (25) plus ΔR1. If the current ventilation volume is greater than the target ventilation volume (Vt), the ventilation volume of the ventilation device (40) decreases, and therefore it is necessary to decrease the rotation speed (Nc) of the compressor (25). Therefore, if the current ventilation volume is greater than the target ventilation volume (Vt), the limit rotation speed (R2) becomes the current rotation speed (Nc) of the compressor (25) minus the limit width (ΔR1).

[0099] Next, in step S41, the control section (100) determines the ventilation restriction volume (Vl) using equation (5).

[0100] Limited ventilation (Vl) = Vc + ΔW / L1' (5) where Vc is the current ventilation rate [m 3 / h], and ΔW is the cooling capacity limit change amount [W] calculated by equation (4). L1' is the ventilation volume 1 m 3 This is the ventilation / cooling load per unit of room temperature, and is the ventilation / cooling load (L1) divided by the target ventilation volume (Vt).

[0101] In step S42, the control section (100) controls the ventilation device (40) so that the ventilation volume of the ventilation device (40) approaches the limit ventilation volume (Vl).

[0102] In step S43, the control unit (100) controls the cooling unit (10A) so that the cooling capacity of the cooling unit (10A) approaches the limited cooling capacity. Here, the limited cooling capacity is a target value of the cooling capacity for limiting the fluctuation range of the cooling capacity of the cooling unit (10A) to a first value or less. Specifically, in step S43, the control unit (100) controls the cooling unit (10A) so that the rotation speed of the compressor (25) approaches the above-mentioned limited rotation speed (R2).

[0103] Next, when the ventilation rate of the ventilation device (40) has not reached the target ventilation rate (Vt) (NO in step S44) and the operation time (t2) has elapsed (YES in step S45), the control unit (100) repeats the processes of steps S41 to S43. When the ventilation rate of the ventilation device (40) reaches the target ventilation rate (Vt) in step S44, the first limiting operation ends.

[0104] Thus, in the first limiting operation, the control unit (100) performs feedforward control using the ventilation cooling load corresponding to the limited ventilation rate (Vl) of the ventilation device (40) as a control index. Therefore, at the time when the ventilation rate of the ventilation device (40) reaches the limited ventilation rate (Vl), the cooling capacity of the cooling unit (10A) approaches the cooling capacity capable of processing the ventilation cooling load (L1). As a result, it is possible to prevent the temperature of the inside air in the inside space (3) from changing significantly due to the ventilation operation of the ventilation device (40). As a result, it is possible to adequately control the ambient temperature of the object.

[0105] In addition, in the first limiting operation, the rate of change of the cooling capacity of the cooling unit (10A) is limited to a first value or less. Specifically, during the operation time (t2), the fluctuation range of the rotation speed of the compressor (25) is limited to a limit value (ΔR1). This makes it possible to avoid problems such as insufficient control of the compressor (25) or breakdowns of the compressor (25) or other devices due to an excessively large fluctuation range of the rotation speed of the compressor (25).

[0106] (7-5) Cooling Priority Mode As described above, in the normal mode, the cooling capacity of the cooling unit (10A) is determined based on the ventilation cooling load. On the other hand, if the ventilation rate of the ventilation device (40) changes significantly in the normal mode, the cooling capacity of the cooling unit (10A) may become excessively large, potentially making it impossible to sufficiently cool the interior of the refrigerator. In this case, the temperature of the air inside the refrigerator may rise, potentially impairing the temperature control of the target items. Therefore, in the cooling priority mode, if the cooling capacity of the cooling unit (10A) exceeds a predetermined value, the control unit (100) limits the ventilation rate of the ventilation device (40).

[0107] The cooling priority mode will be described with reference to FIG.

[0108] In the cooling priority mode, the process is basically the same as in the normal operation mode. In steps S51 to S56, the control section (100) performs the same process as in steps S21 to S26.

[0109] If the index indicating the cooling capacity of the cooling unit (10A) is greater than a predetermined value in step S57, the control unit (100) limits the ventilation rate of the ventilation device (40) in step S58. Specifically, if the rotation speed of the compressor (25) is greater than a second value in step S57, the control unit (100) controls the ventilation device (40) in step S58 so that the ventilation rate of the ventilation device (40) approaches a predetermined value that is smaller than the target ventilation rate (Vt). The control unit (100) may set the ventilation rate of the ventilation device (40) to zero in step S58. As a result, the heat input of the outside air due to the ventilation operation into the internal space (3) can be suppressed, thereby suppressing a temperature rise in the internal space (3). Thereafter, when the difference between the internal temperature (Ti) and the target temperature (Ts) becomes smaller, the rotation speed of the compressor (25) is reduced.

[0110] If the index indicating the cooling capacity of the cooling unit (10A) is smaller than the predetermined value in step S59, the control unit (100) releases the restriction on the ventilation rate of the ventilation device (40) in step S60. Specifically, if the rotation speed of the compressor (25) is smaller than the third value, the control unit (100) releases the restriction on the ventilation rate of the ventilation device (40). Therefore, thereafter, the processes of steps S51 to S56 are executed again. In other words, the control unit (100) controls the ventilation device (40) so that the ventilation rate of the ventilation device (40) approaches the target ventilation rate.

[0111] (8) Effects of the embodiment In this embodiment, the control unit (100) adjusts the cooling capacity of the cooling unit (10A) based on the ventilation / cooling load, which is the cooling load caused by the ventilation operation of the ventilation device (40).

[0112] This can prevent the temperature of the air inside the refrigerator from changing due to an increase or decrease in the ventilation rate caused by the ventilation operation of the ventilation device (40). As a result, the ambient temperature of the interior space (3) can be easily maintained at a target temperature, and the objects can be adequately managed. This can reduce the frequency with which the compressor (25) starts and stops due to changes in the temperature of the air inside the refrigerator, thereby extending the life of the compressor (25).

[0113] In the present embodiment, the control unit (100) controls the ventilation device (40) so that the ventilation rate of the ventilation device (40) approaches a first ventilation rate (target ventilation rate), and adjusts the cooling capacity of the cooling unit (10A) based on the inside cooling load, which is the cooling load inside the refrigerator, and the ventilation cooling load corresponding to the first ventilation rate.

[0114] Therefore, when the ventilation rate converges to the target ventilation rate, the cooling capacity of the cooling unit (10A) reaches a level that can process the ventilation cooling load corresponding to the target ventilation rate, thereby suppressing changes in the temperature of the air inside the refrigerator due to the ventilation operation.

[0115] In the present embodiment, the control unit (100) executes a first control (e.g., step S24) for determining a first cooling capacity (target cooling capacity) of the cooling unit (10A) based on the inside cooling load and the ventilation cooling load corresponding to the first ventilation rate (target ventilation rate), a second control (e.g., step S25) for bringing the ventilation rate of the ventilation device (40) closer to the first ventilation rate (target capacity) after the first control, and a third control (e.g., step S26) for bringing the cooling capacity of the cooling unit (10A) closer to the first cooling capacity (target cooling capacity) after the first control.

[0116] This allows the timing at which the cooling capacity of the cooling unit (10A) reaches the target cooling capacity to be closer to the timing at which the ventilation rate of the ventilation device (40) reaches the target ventilation rate, thereby preventing the temperature of the air inside the refrigerator from changing due to the ventilation operation.

[0117] In the present embodiment, in the ventilation load reduction mode, which is the first mode, the control unit (100) performs a first limiting operation to limit the rate of change of the ventilation rate of the ventilation device (40) so that an index indicating the rate of change of the cooling capacity of the cooling unit (10A) accompanying the ventilation operation of the ventilation device (40) becomes equal to or less than a predetermined value. Specifically, in the first limiting operation, the rate of change of the ventilation rate of the ventilation device (40) is limited so that the rate of change of the rotation speed of the compressor (25) becomes equal to or less than a predetermined value.

[0118] This prevents the fluctuation range of the rotational speed of the compressor (25) from exceeding the limit value, thereby preventing insufficient control of the compressor (25) and preventing breakdowns in the compressor (25) or other devices, thereby ensuring the reliability of the container refrigeration unit (10).

[0119] In this embodiment, the control unit (100) executes the first restriction operation when the first mode is selected by operating the operation unit (110).

[0120] Therefore, depending on the user's operation of the operation unit (110), it is possible to arbitrarily select whether to prioritize ventilation by the ventilation device (40) or suppression of changes in the cooling load of the ventilation device (40).

[0121] In this embodiment, when the index indicating the cooling capacity of the cooling unit (10A) is greater than a predetermined value, the control unit (100) performs the second limiting operation to limit the ventilation rate of the ventilation device (40). Specifically, when the rotation speed of the compressor (25) is greater than a predetermined value, the control unit (100) performs the second limiting operation to limit the ventilation rate of the ventilation device (40).

[0122] Therefore, when the rotation speed of the compressor (25) becomes excessively high due to the ventilation operation of the ventilation device (40) and the inside of the refrigerator cannot be sufficiently cooled, the ventilation cooling load can be reduced, and as a result, the temperature of the air inside the refrigerator can be prevented from rising excessively due to the ventilation operation.

[0123] (9) Variations The above embodiment may be configured as the following modified examples. Below, the differences from the above embodiment will be basically described.

[0124] (9-1) Variation 1 In the first control of step S26 in the normal mode, the control unit (100) of the first modification determines not only the target rotation speed (Nt) of the compressor (25) but also the target opening (Dt) of the expansion valve (31). Specifically, the control unit (100) determines the target opening (Dt) of the expansion valve (31) using the following equation (5):

[0125] Dt=Dc×Nt / Nc...(6) formula Here, Dt is the target opening [pls] of the expansion valve (31), and Nt is the target rotation speed [rps] of the compressor (25) determined in the first control of step S24 as described above, and is the current rotation speed [rps] of the compressor (25).

[0126] In the third control of step S26, the control unit (100) of the first modified example controls the expansion valve (31) so that the rotation speed (Nc) of the compressor (25) approaches the target rotation speed (Nt) and the opening degree of the expansion valve (31) approaches the target opening degree (Dt).

[0127] This allows the opening of the expansion valve (31) to be adjusted in accordance with the control of the rotation speed of the compressor (25), thereby preventing the evaporation temperature of the internal heat exchanger (29) from changing due to the ventilation operation, thereby preventing the temperature of the internal air from changing due to the ventilation operation.

[0128] The control of the expansion valve in the first modification may be applied in the ventilation load suppression mode or the cooling priority mode.

[0129] (9-2) Variation 2 When estimating the ventilation cooling load in step S22, the control unit (100) of the second modification sets the sum of the sensible heat load (Ls) and the sensible heat load (Ls) as the ventilation cooling load (L1). Here, the control unit (100) calculates the latent heat load (LL) using the following equation (7):

[0130] LL=β×Vt×(ho-hi)···(7) formula Here, LL is the latent heat load [W] imparted from the outside air to the inside space (3) by the ventilation operation. Vt is the target ventilation volume [m 3 / h], and β is a coefficient (e.g., 830) that takes into account the latent heat of vaporization of water and the density of air. ho is the absolute humidity of the air outside the cabinet [kg / kg (DA)], and hi is the absolute humidity of the air inside the cabinet [kg / kg (DA)]. The absolute humidity of the air outside the cabinet (Ro) is detected by an outside humidity sensor placed outside the cabinet. The absolute humidity of the air inside the cabinet (Ri) is detected by an inside humidity sensor placed inside the cabinet.

[0131] By calculating the ventilation cooling load in this way, it is possible to determine the target cooling capacity according to the latent heat load, thereby preventing changes in the inside air temperature due to the influence of the latent heat load caused by ventilation operation.

[0132] The control of the second modification may be applied to the ventilation load suppression mode or the cooling priority mode.

[0133] (10) Other embodiments The above-described embodiment and each of the modifications may be configured as follows.

[0134] The container (1) does not have to be for marine transport, but may be for land transport carried by a vehicle such as a trailer or by rail.

[0135] The ventilation device (40) may have only an air supply function of supplying outside air from the exterior space (5) to the interior space (3), and may not have an exhaust function. In other words, the ventilation device (40) may have only an air supply passage (41), and exhaust air may be naturally discharged through an exhaust port provided in the container body (2).

[0136] The ventilation fan of the ventilation device (40) may be a dedicated ventilation fan separate from the interior fan.

[0137] The opening adjustment mechanism for adjusting the opening of the air supply passage (41) or the exhaust passage (42) does not necessarily have to be the open / close lid (45). The opening adjustment mechanism may be a damper or a valve mechanism provided in the air supply passage (41) or the exhaust passage (42).

[0138] The control unit (100) may determine a target ventilation rate for the ventilation device (40) based on the carbon dioxide concentration detected by the carbon dioxide concentration sensor and the target carbon dioxide concentration.

[0139] The container refrigeration system (10) may have an air composition adjusting device that adjusts the composition of oxygen, carbon dioxide, nitrogen, etc., of the air in the interior space (3). The air composition adjusting device adjusts the air in the interior space (3) using, for example, a PSA (Pressure Swing Adsorption) or a gas separation membrane.

[0140] The control unit (100) may adjust the cooling capacity of the cooling unit (10A) based on the ventilation / cooling load corresponding to the current ventilation volume of the ventilation device (40) rather than on the ventilation / cooling load corresponding to the target ventilation volume of the ventilation device (40).

[0141] The control parameters for adjusting the cooling capacity of the cooling unit (10A) are not the rotation speed of the compressor (25), but include the operating frequency of the compressor (25), the evaporation temperature of the internal heat exchanger (29), the air volume of the internal fan (30), the air volume of the external fan (27), and the like.

[0142] Indicators indicating the rate of change in the cooling capacity for determining whether or not to perform the first limiting operation include not only the rotation speed of the compressor (25) but also the operating frequency of the compressor (25), the evaporation temperature of the internal heat exchanger (29), the evaporation pressure of the internal heat exchanger (29), etc.

[0143] In the second limiting operation, the control unit (100) may control the ventilation device (40) based on not only the rotation speed of the compressor (25), but also the operating frequency of the compressor (25), the evaporation temperature of the internal heat exchanger (29), and the evaporation pressure of the internal heat exchanger (29).

[0144] Indicators indicating the cooling capacity of the cooling unit (10A) for determining whether to perform the second limiting operation include not only the rotation speed of the compressor (25) but also the operating frequency of the compressor (25), the evaporation temperature of the internal heat exchanger (29), the evaporation pressure of the internal heat exchanger (29), etc.

[0145] (11) Reference form In a reference embodiment, the control unit (100) adjusts the cooling capacity of the cooling unit (10A) based on the cooling load inside the refrigerator, not on the ventilation cooling load. The cooling load inside the refrigerator is the refrigerator temperature and a target temperature. The control unit (100) controls the ventilation device (40) based on the cooling capacity of the cooling unit (10A) when the ventilation device (40) simultaneously performs a ventilation operation and a cooling operation for cooling the refrigerator interior using the cooling unit (10A). Specifically, the control unit (100) limits the ventilation rate of the ventilation device (40) when an index indicating the cooling capacity of the cooling unit (10A) is greater than a predetermined value. This reduces the cooling load caused by the introduction of outside air when the ventilation operation causes the cooling capacity of the cooling unit (10A) to become excessive. As a result, fluctuations in the temperature of the refrigerator air can be suppressed.

[0146] Although the embodiments and modifications have been described above, it will be understood that various modifications in form and details are possible without departing from the spirit and scope of the claims. Furthermore, the above embodiments, modifications, and other embodiments may be combined or substituted as appropriate as long as the functionality of the subject matter of the present disclosure is not impaired.

[0147] The terms "first," "second," "third," etc. mentioned above are used to distinguish the terms to which these terms are attached, and do not limit the number or order of the terms. [Industrial Applicability]

[0148] As described above, the present disclosure is useful for container refrigeration systems. [Explanation of symbols]

[0149] 1 container 10 Container refrigeration equipment 10A Cooling Unit 25 Compressor 26 External heat exchanger (radiator) 29 Internal heat exchanger (evaporator) 31 Expansion valve (expansion mechanism) 40 Ventilation Equipment 100 control section 110 Operation section L1 ventilation cooling load L2 Cooling load inside the storage

Claims

1. a cooling unit (10A) including a compressor (25), a radiator (26), an expansion mechanism (31), and an evaporator (29), and configured to perform a cooling operation of cooling the interior of the container (1) by the evaporator (29); a ventilation device (40) for supplying outside air into the container (1); a control unit (100) that controls the cooling unit (10A) and the ventilation device (40); a sensor (53) for detecting an oxygen concentration or a carbon dioxide concentration inside the container (1); The control unit (100) adjusts the cooling capacity of the cooling unit (10A) based on a ventilation cooling load, which is a cooling load associated with the ventilation operation of the ventilation device (40); The control unit (100) determining a first ventilation volume, which is a target ventilation volume for the ventilation device, based on the detected value of the sensor; The ventilation device (40) is controlled so that the ventilation volume of the ventilation device (40) approaches a first ventilation volume, and at the same time, the cooling capacity of the cooling unit (10A) is adjusted based on an internal cooling load, which is a cooling load inside the storage compartment, and the ventilation cooling load corresponding to the first ventilation volume. Refrigeration equipment for containers.

2. The control unit (100) a first control that determines a first cooling capacity of the cooling unit (10A) based on the inside cooling load and the ventilation cooling load corresponding to the first ventilation rate; after the first control, a second control for bringing the ventilation volume of the ventilation device (40) closer to the first ventilation volume; After the first control, a third control is performed to bring the cooling capacity of the cooling unit (10A) closer to the first cooling capacity.

2. The container refrigeration system of claim 1.

3. a cooling unit (10A) including a compressor (25), a radiator (26), an expansion mechanism (31), and an evaporator (29), and configured to perform a cooling operation of cooling the interior of the container (1) by the evaporator (29); a ventilation device (40) for supplying outside air into the container (1); a control unit (100) that controls the cooling unit (10A) and the ventilation device (40), the control unit (100) adjusts the cooling capacity of the cooling unit (10A) by adjusting the rotation speed of the compressor (25) based on a ventilation cooling load, which is a cooling load associated with the ventilation operation of the ventilation device (40); The control unit (100) performs a first limiting operation to limit the rate of change in the ventilation volume of the ventilation device (40) so that an index indicating the rate of change in the rotation speed of the compressor (25) due to the ventilation operation of the ventilation device (40) becomes equal to or less than a predetermined value. Refrigeration equipment for containers.

4. The control unit (100) executes the first limiting operation when a first mode is selected by operating an operation unit (110).

4. A container refrigeration system according to claim 3.

5. The control unit (100) controls the ventilation device (40) based on the cooling capacity of the cooling unit (10A).

3. A container refrigeration system according to claim 1 or 2.

6. The control unit (100) performs a second limiting operation to limit the ventilation rate of the ventilation device (40) when the index indicating the cooling capacity of the cooling unit (10A) is greater than a predetermined value.

6. A container refrigeration system according to claim 5.

7. The control unit (100) performs the second limiting operation when the second mode is selected by operating the operation unit (110).

7. A container refrigeration system according to claim 6.

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