Container refrigeration equipment

Abstract

To reduce a cooling load at an initial cooling operation from a start of a freezer for a container.SOLUTION: A control part starts a ventilation operation for supplying air outside a container into the container by a ventilation device (40), when a first condition that the temperature of the air outside the container is lower than the temperature of the air in the container in a first period until an initial cooling operation starts from activation of a freezer (10) for a container, or a second period until a rotation number of a compressor (25) reaches a predetermined value from the start of the initial cooling operation.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 a container refrigeration unit such as that described in Patent Document 1, the cooling load inside the unit is large during the first cooling operation after the unit is started up. This is because the temperature of the air inside the unit is relatively high when the container refrigeration unit is started up, and it is necessary to lower the temperature of this air to a temperature sufficient to cool the object.

[0005] An object of the present disclosure is to reduce the cooling load during the initial cooling operation after starting up a container refrigeration system. [Means for solving the problem]

[0006] The first aspect relates to 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) supplying outside air to the interior of the container (1), and a control unit (100) controlling the cooling unit (10A) and the ventilation device (40). The control unit (100) starts a ventilation operation to supply outside air to the interior of the container (1) by the ventilation device (40) when a first condition is met, that is, the temperature of the outside air is lower than the temperature of the inside air, during a first period from the start of the container refrigeration system (10) to the start of the first cooling operation, or during a second period from the start of the first cooling operation to the time when the rotation speed of the compressor (25) reaches a predetermined value.

[0007] In a first aspect, the container refrigeration system (10) starts the ventilation operation of the ventilation device (40) when a first condition is met in a first period or a second period, that is, when the temperature of the outside air is lower than the temperature of the inside air. The first period is the period from start-up of the container refrigeration system to the start of the first cooling operation. During the first period, the air inside the container (1) has not yet been cooled, so the temperature of the inside air is relatively high. Therefore, the cooling load inside the container (1) is relatively high. Furthermore, during the first period, the temperature of the inside air may become higher than the outside air due to the influence of radiant heat on the container (1) caused by solar radiation, etc., and this increases the likelihood that the first condition will be met. Therefore, in the first aspect, the control unit (100) starts the ventilation operation to supply outside air into the container (1) when the first condition is met during the first period. This allows the cooling load inside the container (1) to be reduced by using the outside air before the cooling operation is started.

[0008] The second period is a period from the start of the first cooling operation after the container refrigeration system is started until the rotation speed of the compressor (25) reaches a predetermined value. During the second period, the air inside the container (1) is not yet sufficiently cooled, and therefore the temperature of the air inside the container (1) is relatively high. Therefore, the cooling load inside the container (1) is relatively high. Even during the second period, the temperature of the air inside the container (1) becomes higher than the air outside the container (1) due to the influence of radiant heat on the container (1) caused by solar radiation, and the like, making it more likely that the first condition will be met. Therefore, in the first aspect, when the first condition is met during the second period, the control unit (100) starts a ventilation operation to supply outside air into the container (1). This allows the cooling load inside the container (1) to be reduced by using the outside air after the start of the cooling operation and before the temperature of the air inside the container (1) has sufficiently decreased.

[0009] In the second aspect, in the first aspect, the control unit (100) stops the ventilation operation when a second condition is met, that is, the difference between the temperature of the air inside the refrigerator and the temperature of the air outside the refrigerator is equal to or less than a predetermined value during the first period or the second period.

[0010] In the second aspect, if the difference between the temperature of the air inside the refrigerator and the temperature of the air outside the refrigerator is equal to or smaller than a predetermined value during the first or second period, the control unit (100) stops the ventilation operation. This prevents excessive ventilation operation under conditions in which the inside of the refrigerator cannot be sufficiently cooled by the outside air.

[0011] In the third aspect, in the second aspect, when a second condition is met in the first period, the control unit (100) stops the ventilation operation and starts the first cooling operation.

[0012] In the third aspect, the cooling operation starts when the second condition is met, so the interior of the container can be cooled quickly. At this time, ventilation operation is not performed, so that an increase in the cooling load inside the container due to ventilation during the cooling operation can be suppressed.

[0013] In a fourth aspect, in the third aspect, the ventilation device (40) includes an air supply passage (41) for supplying outside air into the refrigerator and an opening adjustment mechanism (45) for adjusting the opening of the air supply passage (41), and the control unit (100) controls the opening adjustment mechanism (45) to open the air supply passage (41) close to full opening during ventilation operation.

[0014] In the fourth aspect, the ventilation rate can be finely adjusted by adjusting the opening of the air supply passageway (41) using the opening adjustment mechanism (45). When the first condition is met in the first period, the control unit (100) performs the ventilation operation. At this time, the opening of the air supply passageway (41) is increased, thereby ensuring the maximum amount of outside air supplied to the refrigerator. As a result, the second condition is met quickly, and the first cooling operation can be started quickly. [Brief explanation of the drawings]

[0015] [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 control flowchart from when the container refrigeration unit is started up until the cooling operation starts. [Figure 7] FIG. 7 is a control flowchart during cooling operation. [Figure 8] FIG. 8 is a control flowchart relating to the ventilation operation of the first modification. DETAILED DESCRIPTION OF THE INVENTION

[0016] 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.

[0017] (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.

[0018] 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).

[0019] 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).

[0020] (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).

[0021] 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).

[0022] (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.

[0023] 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).

[0024] 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.

[0025] (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).

[0026] (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).

[0027] 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).

[0028] 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.

[0029] (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 external heat exchanger (26) is supported by the casing (11) so as to extend across the casing body (12) and the partition plate (13). The internal heat exchanger (29) is a fin-and-tube heat exchanger.

[0030] (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.

[0031] The refrigerant circuit (R) mainly includes a compressor (25), an external heat exchanger (26), an expansion valve (31), and an internal heat exchanger (29).

[0032] 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.

[0033] 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.

[0034] 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).

[0035] 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.

[0036] 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).

[0037] 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.

[0038] (2-6) 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).

[0039] 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).

[0040] 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).

[0041] (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).

[0042] 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).

[0043] 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).

[0044] 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).

[0045] 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).

[0046] 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.

[0047] 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).

[0048] 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).

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] (4) Sensor The container refrigeration system (10) has a plurality of sensors, including an inside temperature sensor (51) and an outside temperature sensor (52), as shown in Figures 2 and 5 .

[0054] 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).

[0055] 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).

[0056] (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.

[0057] 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 rotation angle of the opening / closing lid (45), i.e., the opening of the air supply passage (41) and the air exhaust passage (42) of the ventilation device (40).

[0058] 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).

[0059] (6) Power supply As shown in FIG. 5, the container refrigeration unit (10) has a power supply (120). The power supply (120) is a main power supply for starting the container refrigeration unit (10). The power supply (120) may be a battery built into the container refrigeration unit (10) or a secondary power supply to which power is supplied from a power source of a vehicle or a commercial power source. When the power supply (120) is turned on, the container refrigeration unit (10) starts up. When the container refrigeration unit (10) starts up, the power supply (120) and each component of the container refrigeration unit (10) become electrically conductive. The components here include the compressor (25), the internal fan (30), the external fan (27), the expansion valve (31), the motor (43) of the ventilation device (40), the control unit (100), and the operating unit (110). In this state, an operation command is input to the control unit (100), and the above-mentioned cooling operation and the like are started.

[0060] (7) Cooling load issues during pull-down operation In the cooling operation described above, a cooling operation is performed by the internal heat exchanger (29) serving as an evaporator to cool the interior of the container (1). In the first cooling operation after the container refrigeration system (10) is started, it is necessary to lower the relatively high temperature of the internal air to a target temperature for storing the object. Hereinafter, the first cooling operation is also referred to as a "pull-down operation." When the temperature of the internal air reaches the target temperature through the pull-down operation, the pull-down operation ends and the system enters a so-called thermo-off state. Thereafter, when the temperature of the internal air rises, the cooling operation is performed again. The pull-down operation can be considered to be the first cooling operation performed after the object is placed in the internal space (3) of the container (1). The pull-down operation can also be considered to be the cooling operation performed until the container refrigeration system (10) is first started and enters a thermo-off state.

[0061] In the pull-down operation, the temperature of the air inside the container is lowered by a large amount, so the cooling load is larger than in the second and subsequent cooling operations. In addition, because the container (1) is installed outdoors, the temperature of the air inside the container may rise further due to the influence of radiant heat caused by sunlight. This poses a problem in that the power consumption required to process the cooling load during the pull-down operation is large.

[0062] (8) Ventilation operation To solve the above-described problems, the control unit (100) of this embodiment performs a ventilation operation to supply outside air into the compartment using the ventilation device (40) when a first condition is met that the temperature of the outside air is lower than the temperature of the inside air during a first period from the start of the container refrigeration system (10) to the start of the first cooling operation. This control will be described in detail. Fig. 6 is a flowchart showing an outline of the control from the start of the container refrigeration system (10) to the start of the cooling operation, and Fig. 7 is a flowchart showing an outline of the control of the cooling operation.

[0063] As shown in Fig. 6, in step S11, the container refrigeration unit (10) is started up. Specifically, when a user or the like operates the operation unit (110) to turn on the power supply (120) of the container refrigeration unit (10), the container refrigeration unit (10) is started up. In step S11, the pull-down operation of the container refrigeration unit (10) has not yet been performed.

[0064] In step S12, the control unit (100) determines whether or not a command to start the cooling operation has been issued. When the user operates the operation unit (110) to select the cooling operation, a command to start the cooling operation is input from the operation unit (110) to the control unit (100). As a result, the process proceeds to step S13.

[0065] In step S13, the outside-compartment temperature (To) is compared with the inside-compartment temperature (Ti). The outside-compartment temperature (To) is detected by the outside-compartment temperature sensor (52). The inside-compartment temperature (Ti) is detected by the inside-compartment temperature sensor (51). The control section (100) determines whether or not a first condition is met, that is, the outside-compartment temperature (To) is lower than the inside-compartment temperature (Ti). If the first condition is not met, the outside-compartment temperature (To) is equal to or higher than the inside-compartment temperature (Ti). Therefore, in this case, the ventilation operation is not performed, and the process proceeds to step S17, where the cooling operation is started. As a result, the first cooling operation (pull-down operation) is performed.

[0066] If the first condition is met in step S13, that is, the outside-compartment temperature (To) is lower than the inside-compartment temperature (Ti), the process proceeds to step S14. In step S14, the control unit (100) starts the ventilation operation of the ventilation device (40). Specifically, the control unit (100) operates the inside fan (30). At the same time, the control unit (100) controls the opening / closing cover (45) to approach the fully open position shown in FIG. 4(C). In other words, the control unit (100) controls the opening / closing cover (45) to approach the fully open position of the air supply passage (41) and the air exhaust passage (42) of the ventilation device (40). As a result, the outside air in the outside space (5) is supplied to the inside space (3) through the air supply passage (41). The inside air in the inside space (3) is discharged to the outside space (5) through the air supply passage (41). As a result, the air inside the internal space (3) is cooled by the air outside the internal space (3), and the temperature of the air inside the internal space (3) decreases.

[0067] In step S15, the control unit (100) determines whether a second condition is met, that is, the difference (ΔT=Ti-To) between the inside temperature (Ti) and the outside temperature (To) is equal to or less than a predetermined value A. If the second condition is met, the process proceeds to step S16, and the control unit (100) terminates the ventilation operation. If the difference between the inside temperature (Ti) and the outside temperature (To) becomes small, the ventilation operation cannot sufficiently cool the inside air. Therefore, by terminating the ventilation operation when ΔT is equal to or less than the predetermined value A, excessive ventilation can be suppressed. The predetermined value A may be 0°C. In this case, the second condition can be said to be a condition that the inside temperature (Ti) is equal to or less than the outside temperature (To).

[0068] Next, in step S17, the control section (100) starts the cooling operation. The timing of the end of the ventilation operation in step S16 and the start of the cooling operation in step S17 are the same. Therefore, after the second condition is met, the cooling operation can be started promptly.

[0069] As shown in FIG. 7, when the cooling operation is performed, the first cooling operation, i.e., the pull-down operation, is started in step S21. In the cooling operation, the control unit (100) controls the rotation speed of the compressor (25) according to the difference between the inside temperature (Ti) and the target temperature (Ts). The larger the difference between the inside temperature (Ti) and the target temperature (Ts), the higher the rotation speed of the compressor (25). Conversely, the smaller this difference, the lower the rotation speed of the compressor (25). As described above, in the first period, when the inside temperature (Ti) is higher than the outside temperature (To), the ventilation operation reduces the temperature of the inside air. Therefore, in the pull-down operation, the rotation speed of the compressor (25) can be reduced, thereby reducing the input power of the compressor (25) and, consequently, the power consumption.

[0070] Thereafter, when the internal temperature (Ti) reaches the target temperature (Ts) in step S22, the control unit (100) ends the pull-down operation in step S23. Specifically, in step S23, the control unit (100) stops the compressor (25) and puts the internal heat exchanger (29) into a sleep state. In other words, the control unit (100) puts the cooling unit (10A) into a thermo-off state.

[0071] Next, in step S24, when the internal temperature (Ti) becomes greater than the target temperature (Ts) plus the predetermined value B, the process proceeds to step S21, and the control unit (100) executes a second cooling operation. In other words, the control unit (100) puts the cooling unit (10A) into the thermo-on state. In the second and subsequent cooling operations, the difference between the internal temperature (Ti) and the target temperature (Ts) is relatively small. Therefore, the cooling load of the second and subsequent cooling operations is extremely small compared to the pull-down operation.

[0072] If a command to end the cooling operation is input to the control unit (100) during the cooling operation or when the cooling unit (10A) is in the thermo-off state (YES in step S25 or step S27), the process proceeds to step S26, where the cooling operation is ended.

[0073] (9) Effects of the embodiment In this embodiment, when a first condition is met that the temperature of the outside air is lower than the temperature of the inside air during a first period from the start of the container refrigeration unit (10) to the start of the first cooling operation, the control unit (100) causes the ventilation device (40) to start a ventilation operation of supplying outside air into the inside of the container. Note that the "first period" here includes the time when the container refrigeration unit (10) is started and the time when the first cooling operation starts.

[0074] By performing the ventilation operation in the first period, the temperature inside the refrigerator (Ti) at the start of the pull-down operation is lowered, thereby reducing the cooling load inside the refrigerator. As a result, the input power of the compressor (25) during the pull-down operation and the power consumption can be reduced. As a result, the energy efficiency of the container refrigeration system (10) can be improved. When the ventilation operation is performed in the first period, the so-called cold energy generated by the cooling operation of the cooling unit (10A) is not discharged to the outside of the refrigerator.

[0075] In this embodiment, the control unit (100) stops the ventilation operation when a second condition is met in the first period, that is, the difference between the temperature of the air inside the refrigerator and the temperature of the air outside the refrigerator is equal to or less than a predetermined value A. This makes it possible to prevent excessive ventilation operation under conditions in which the cooling effect of the air outside the refrigerator is low. In particular, under conditions in which the temperature of the air outside the refrigerator is lower than the temperature of the air inside the refrigerator, it is possible to prevent an increase in the cooling load inside the refrigerator due to ventilation.

[0076] In this embodiment, when the second condition is satisfied during the first period, the control unit (100) stops the ventilation operation and starts the initial cooling operation. This allows the pull-down operation to start quickly. Since the ventilation operation is not performed during the pull-down operation, an increase in the cooling load due to ventilation can be avoided.

[0077] In this embodiment, the control unit (100) controls the opening / closing cover (45) in the ventilation operation so that the air supply passage (41) and the air exhaust passage (42) of the ventilation device (40) are nearly fully open. This increases the ventilation volume of the ventilation device (40) in the ventilation operation, thereby quickly reducing the temperature of the air inside the refrigerator. As a result, the cooling load inside the refrigerator can be quickly reduced, and the pull-down operation can be quickly started.

[0078] (10) Variation The above embodiment may be configured as the following modified examples. Below, the differences from the above embodiment will be basically described.

[0079] (10-1) Variation 1 The control unit (100) of the first modification performs a ventilation operation when a first condition is satisfied in a first period, as in the above-described embodiment. Additionally, the control unit (100) of the first modification performs a ventilation operation in which the ventilation device (40) supplies outside air to the inside of the refrigerator when a first condition is satisfied in a second period, that is, when the temperature of the outside air is lower than that of the inside air. This period is from the start of the first cooling operation after startup of the container refrigeration system until the rotational speed of the compressor (25) reaches a predetermined value C. The predetermined value C is a target value for gradually increasing the rotational speed of the compressor (25) after starting the pull-down operation. The target value may be a rotational speed corresponding to the rated capacity of the cooling unit (10A) or the maximum value within the control range of the rotational speed of the compressor (25). The control unit (100) may not perform a ventilation operation in the first period as in the above-described embodiment, but may perform a ventilation operation only in the second period.

[0080] The ventilation operation of the first modification will be described with reference to Fig. 8. In step S31, when the pull-down operation is started, the control unit (100) starts the compressor (25). At this time, the control unit (100) gradually increases the rotation speed of the compressor (25) so that the rotation speed reaches a target value.

[0081] In step S32, the control unit (100) determines whether a first condition is met, that is, the outside temperature (To) is lower than the inside temperature (Ti). If the first condition is not met, the process proceeds to the cooling operation shown in FIG. 7. If the first condition is met, the process proceeds to step S33. If the rotation speed of the compressor (25) is not equal to or higher than the predetermined value C (NO in step S33), in step S34, the control unit (100) executes a ventilation operation, as in the above embodiment. This reduces the cooling load inside the refrigerator due to ventilation.

[0082] Next, in step S35, if the difference between the inside temperature (Ti) and the outside temperature (ΔT=Ti−To) is equal to or less than a predetermined value A, the control unit (100) terminates the ventilation operation in step S36. Here, the predetermined value A is preferably zero. That is, the control unit (100) of the first modification terminates the ventilation operation when the inside temperature (Ti) is equal to or less than the outside temperature (To). This makes it possible to avoid an increase in the cooling load due to the ventilation operation at the start of the cooling operation.

[0083] During a second period from the start of the pull-down operation until the rotational speed of the compressor (25) reaches the predetermined value C, the inside of the refrigerator is not sufficiently cooled, and the cooling load inside the refrigerator is high. Furthermore, there is a possibility that the inside temperature (Ti) will be higher than the outside temperature (To). Therefore, by performing a ventilation operation when the first condition is satisfied during the second period, the cooling load inside the refrigerator during the pull-down operation can be reduced. As a result, the power consumption of the container refrigeration system (10) can be reduced. When the ventilation operation is performed during the second period, the so-called cold energy produced by the cooling operation of the cooling unit (10A) is hardly discharged to the outside of the refrigerator.

[0084] (10-2) Variation 2 In this embodiment, the control unit (100) performs the ventilation operation when the outside temperature (To) is lower than the inside temperature (Ti) after the command to start the cooling operation in the first period is input. However, the control unit (100) may also perform the ventilation operation when the outside temperature (To) is lower than the inside temperature (Ti) before the command to start the cooling operation in the first period is input. In this case, when the command to start the cooling operation is subsequently issued, the inside temperature (Ti) can be lowered by the ventilation operation. As a result, the second condition is quickly established after the command to start the cooling operation is issued, and the control unit (100) can quickly end the ventilation operation and start the cooling operation.

[0085] (10-3) Variation 3 When the second condition is satisfied in the first period, the control unit (100) may first terminate the ventilation operation and then start the pull-down operation after a predetermined time has elapsed since the end of the ventilation operation. In this case, it is possible to reliably prevent the cooling load inside the refrigerator from increasing due to the influence of ventilation during the pull-down operation.

[0086] (10-4) Variation 4 At the start of the cooling operation, before the pull-down operation, the control unit (100) may execute a preliminary operation such as a refrigerant recovery operation for recovering refrigerant remaining in the refrigerant circuit (R) or an oil recovery operation for recovering oil remaining in the refrigerant circuit (R). In the preliminary operation, the control unit (100) sets the rotation speed of the compressor (25) to a predetermined value lower than the maximum rotation speed, and returns the refrigerant and oil to the compressor (25) and the like.

[0087] The control unit (100) may start the ventilation operation when a first condition is satisfied during the preliminary operation. The period of the preliminary operation is included in a first period from the start of the container refrigeration system (10) to the start of the first cooling operation.

[0088] (10-5) Variation 5 The control unit (100) may start the ventilation operation when a condition is met in the first period or the second period that the outside air temperature (To) is lower than the temperature (Ti-E) obtained by subtracting a predetermined value E from the inside air temperature (Ti). When this condition is met, the outside air temperature (To) becomes lower than the inside air temperature (Ti). In other words, this condition is included in the first condition.

[0089] (11) Other embodiments The above-described embodiment and each of the modifications may be configured as follows.

[0090] 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.

[0091] 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.

[0092] 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).

[0093] The ventilation fan of the ventilation device (40) may be a dedicated ventilation fan separate from the interior fan.

[0094] 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).

[0095] In the ventilation operation of the above-described embodiment and each modified example, the control unit (100) controls the opening adjustment mechanism (45) to open the air supply passage (41) nearly fully during the ventilation operation. In this case, the opening of the air supply passage (41) may be fully opened or may be set to a predetermined opening smaller than fully opened during the ventilation operation. The opening of the air supply passage (41) is preferably 50% or more, more preferably 90% or more, of the total flow path area. Furthermore, the control unit (100) preferably controls the opening adjustment mechanism (45) to open the air supply passage (41) fully during the ventilation operation. This maximizes the ventilation volume of the ventilation device (40) during the ventilation operation, thereby quickly reducing the temperature of the air inside the refrigerator. As a result, the cooling load inside the refrigerator can be quickly reduced, and the pull-down operation can be quickly initiated.

[0096] 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.

[0097] 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]

[0098] As described above, the present disclosure is useful for container refrigeration systems. [Explanation of symbols]

[0099] 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 41 Air supply passage 45 Opening / closing lid (opening adjustment mechanism) 100 control section

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), the control unit (100) is configured to increase the rotation speed of the compressor (25) as the difference between the inside temperature and the target temperature increases during the cooling operation; The control unit (100) The container refrigeration system (10) is configured to perform a pull-down operation, which is the first cooling operation after the container refrigeration system (10) is started and is a cooling operation that is performed until the temperature of the inside air reaches a target temperature and reaches a thermo-off state. during a first period from when the container refrigeration unit (10) is started until the pull-down operation is started, when a first condition is met that the temperature of the outside air is lower than the temperature of the inside air, the ventilation unit (40) starts a ventilation operation of supplying the outside air into the inside of the container, The ventilation operation is not performed during the pull-down operation. Refrigeration equipment for containers.

2. 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) that supplies 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) starts a ventilation operation of supplying outside air into the container by the ventilation device (40) when a first condition is met that the temperature of the outside air is lower than the temperature of the inside air during a second period from the start of the first cooling operation after the container refrigeration unit is started until the rotation speed of the compressor (25) reaches a predetermined value; The predetermined value is a target value when the cooling operation is started and the rotation speed of the compressor (25) is increased. Refrigeration equipment for containers.

3. The control unit (100) stops the ventilation operation when a second condition is met, that is, the difference between the temperature of the air inside the compartment and the temperature of the air outside the compartment is equal to or less than a predetermined value during the first period or the second period.

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

4. When the second condition is satisfied during the first period, the control unit (100) stops the ventilation operation and starts the first cooling operation.

4. A container refrigeration system according to claim 3.

5. The ventilation device (40) an air supply passageway (41) for supplying outside air into the refrigerator; an opening adjustment mechanism (45) that adjusts the opening of the air supply passage (41); In the ventilation operation, the control section (100) controls the opening adjustment mechanism (45) so as to bring the air supply passage (41) close to full opening.

5. A container refrigeration system according to claim 4.

Images