Cooling device and method for operating cooling device

Abstract

To provide a cooling device which can inhibit deterioration of performance caused by ice accumulation in a turbine when started while inhibiting increase in the size.SOLUTION: A cooling device for cooling a cooling chamber of a refrigeration container comprises: a turbine for expanding air drawn from the cooling chamber; and a control device for controlling operation of the turbine. The control device includes a start-up operation unit that, when the cooling device is started, operates the turbine at a first rotation speed until an inlet temperature of the turbine drops below a preset inlet-side prescribed temperature, and, when the inlet temperature of the turbine is lower than the inlet-side prescribed temperature, operates the turbine at a second rotation speed greater than the first rotation speed.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a cooling device for cooling a cooling chamber of a refrigerated container and a method of operating the cooling device.

Background Art

[0002] For example, Patent Document 1 discloses a cooling device using an air refrigerant cycle (a system that cools air sucked from a cooling chamber and sends the cooled air back to the cooling chamber). Such a cooling device includes a turbine that expands and cools the air sucked from the cooling chamber.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When starting the cooling device, if the rotational speed of the turbine is rapidly increased, the moisture contained in the air sucked from the cooling chamber may freeze inside the turbine. When ice forms inside the turbine, the flow rate of the air flowing through the turbine decreases, leading to a deterioration in the performance of the cooling device. In the cooling device described in Patent Document 1, since an ice catcher is installed on the air outlet side rather than the expander (turbine), there is a risk of ice formation inside the turbine when the cooling device is started. Furthermore, unlike a refrigerator having a large-capacity cooling chamber (for example, a large refrigerated warehouse), the size of the cooling device installed in a refrigerated container is limited, so it is desirable to suppress an increase in the size of the cooling device.

[0005] In view of the above problems, the present disclosure aims to provide a cooling device and a method of operating the cooling device that can suppress a decrease in performance due to ice formation inside the turbine when starting up while suppressing an increase in size.

Means for Solving the Problem

[0006] To achieve the above object, a cooling device according to the present disclosure is a cooling device for cooling a cooling chamber of a refrigerated container, and includes a turbine that expands air sucked from the cooling chamber, and a control device that controls the operation of the turbine. When the cooling device is started, the control device operates the turbine at a first rotational speed until the inlet temperature of the turbine drops below a preset inlet-side specified temperature, and includes a startup operation unit that operates the turbine at a second rotational speed greater than the first rotational speed when the inlet temperature of the turbine is less than the inlet-side specified temperature.

[0007] To achieve the above object, a cooling device according to the present disclosure is a cooling device for cooling a cooling chamber of a refrigerated container, and includes a turbine that expands air sucked from the cooling chamber, and a control device that controls the operation of the turbine. When the cooling device is started, the control device operates the turbine at a first rotational speed until the outlet temperature of the turbine drops below a preset outlet-side specified temperature, and includes a startup operation unit that operates the turbine at a second rotational speed greater than the first rotational speed when the outlet temperature of the turbine is less than the outlet-side specified temperature.

[0008] To achieve the above object, a cooling device according to the present disclosure is a cooling device for cooling a cooling chamber of a refrigerated container, and includes a turbine that expands air sucked from the cooling chamber, and a control device that controls the operation of the turbine. When the cooling device is started, the control device operates the turbine at a first rotational speed until the outlet temperature of the turbine drops below a preset outlet-side specified temperature, and operates the turbine at a second rotational speed greater than the first rotational speed when the outlet temperature of the turbine is less than the outlet-side specified temperature. The control device operates the turbine at the second rotational speed until the inlet temperature of the turbine drops below a preset inlet-side specified temperature, and includes a startup operation unit that operates the turbine at a third rotational speed greater than the second rotational speed when the inlet temperature of the turbine is less than the inlet-side specified temperature.

[0009] To achieve the above object, a method for operating a cooling device according to the present disclosure is a method for operating a cooling device for cooling a cooling chamber of a refrigerated container. The method for operating a cooling device including a turbine that expands air sucked from the cooling chamber is as follows: when the cooling device is started, the turbine is operated at a first rotational speed until the inlet temperature of the turbine drops below a preset inlet-side specified temperature. When the inlet temperature of the turbine is less than the inlet-side specified temperature, the turbine is operated at a second rotational speed greater than the first rotational speed.

[0010] To achieve the above object, a method for operating a cooling device according to the present disclosure is a method for operating a cooling device for cooling a cooling chamber of a refrigerated container. The method for operating a cooling device including a turbine that expands air sucked from the cooling chamber is as follows: when the cooling device is started, the turbine is operated at a first rotational speed until the outlet temperature of the turbine drops below a preset outlet-side specified temperature. When the outlet temperature of the turbine is less than the outlet-side specified temperature, the turbine is operated at a second rotational speed greater than the first rotational speed.

[0011] To achieve the above object, a method for operating a cooling device according to the present disclosure is a method for operating a cooling device for cooling a cooling chamber of a refrigerated container. The method for operating a cooling device including a turbine that expands air sucked from the cooling chamber is as follows: when the cooling device is started, the turbine is operated at a first rotational speed until the outlet temperature of the turbine drops below a preset outlet-side specified temperature. When the outlet temperature of the turbine is less than the outlet-side specified temperature, the turbine is operated at a second rotational speed greater than the first rotational speed. When the inlet temperature of the turbine drops below a preset inlet-side specified temperature, the turbine is operated at the second rotational speed. When the inlet temperature of the turbine is less than the inlet-side specified temperature, the turbine is operated at a third rotational speed greater than the second rotational speed.

Advantages of the Invention

[0012] According to the cooling device and the operation method of the cooling device of the present disclosure, it is possible to suppress a decrease in performance due to icing in the turbine when starting up while suppressing an increase in size.

Brief Description of the Drawings

[0013]

Figure 1

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Mode for Carrying Out the Invention

[0014] Hereinafter, a cooling device and an operation method of the cooling device according to an embodiment of the present disclosure will be described with reference to the drawings. Such an embodiment shows one aspect of the present disclosure, does not limit this disclosure, and can be arbitrarily changed within the scope of the technical idea of this disclosure.

[0015] The cooling device according to the present disclosure cools the cooling chamber of a refrigerated container. This cooling device applies a method (air refrigerant cycle) of cooling the air extracted from the cooling chamber and sending the cooled air back to the cooling chamber.

[0016] FIG. 1 is a diagram schematically showing an example of the configuration of a refrigerated container 100. As illustrated in FIG. 1, the refrigerated container 100 includes a main body 102 and a cooling device 1 according to the present disclosure.

[0017] The main body 102 has a rectangular tube shape and includes an upper wall, a lower wall, a left wall, a right wall, and a rear wall, with an opening at the front. The cooling device 1 is fitted into the front surface of the main body 102. The inside of the main body 102 is surrounded by the upper wall, the lower wall, the left wall, the right wall, the rear wall, and the cooling device 1 to define a cooling chamber 101. Although not shown, the cooling chamber 101 may be provided with an openable door on at least one of the left wall, the right wall, and the rear wall so that an operator can enter and exit the cooling chamber 101. In some embodiments, the main body 102 includes a front wall, and the cooling device 1 is fitted into the front wall.

[0018] The cooling device 1 applies an air refrigerant cycle as described above, cools the air sucked from the cooling chamber 101 (hereinafter referred to as the suction air A2) with a turbine 2 (expansion turbine) to generate cooling air A1, and sends this cooling air A1 to the cooling chamber 101. In the embodiment illustrated in FIG. 1, the cooling device 1 is configured to be able to maintain the temperature of the cooling chamber 101 in the range of -40 degrees or more and less than 20 degrees. That is, the refrigerated container 100 illustrated in FIG. 1 is a low-temperature container (so-called reefer container). In some embodiments, the refrigerated container 100 is an ultra-low temperature container or a cryogenic container capable of maintaining the internal temperature of the cooling chamber 101 lower than -40 degrees.

[0019] <Cooling device> (Configuration) The configuration of the cooling device 1A (1) according to the first embodiment will be described. FIG. 2 is a diagram schematically showing the configuration of the cooling device 1A according to the first embodiment. As shown in FIG. 2, the cooling device 1A includes a turbine 2 and a control device 4. In the form illustrated in FIG. 2, the cooling device 1A further includes an air line 6, a heat exchanger 8, a compressor 10, and an air cooler 12.

[0020] The air line 6 is constituted by, for example, a pipe or a duct, and a flow path is formed inside from sucking the suction air A2 from the cooling chamber 101 to sending the cooled cooling air A1 to the cooling chamber 101. The heat exchanger 8, the compressor 10, the air cooler 12, and the turbine 2 are provided in the air line 6. The suction air A2 flows through the heat exchanger 8, the compressor 10, the air cooler 12, the heat exchanger 8, and the turbine 2 in this order from the upstream side in the flow direction through the air line 6.

[0021] The heat exchanger 8 cools the suction air A2 compressed by the compressor 10 using the suction air A2 immediately after being sucked from the cooling chamber 101 as a refrigerant through a heat transfer wall (not shown). The suction air A2 cooled by the heat exchanger 8 is supplied to the turbine 2. The suction air A2 used as a refrigerant becomes normal temperature (15 degrees to 30 degrees) and is supplied to the compressor 10.

[0022] The compressor 10 compresses the suction air A2 that has been brought to room temperature by the heat exchanger 8, and raises the temperature and pressure of this suction air A2. In the form illustrated in FIG. 2, the cooling device 1 further includes a motor 14 and a pair of drive shafts 15a and 15b that extend coaxially from the motor 14. The compressor 10 is connected to the motor 14 by one of the drive shafts 15a and is driven by the motor 14. Further, the power generated by the turbine 2 is transmitted via the pair of drive shafts 15a and 15b, and the power of the turbine 2 can be used as auxiliary power for driving.

[0023] The air cooler 12 cools (pre-cools) the suction air A2 that has been heated to a high temperature and high pressure by the compressor 10. The air cooler 12 is, for example, a fin-tube type heat exchanger and includes a cooling water flow path through which cooling water flows. The air cooler 12 exchanges heat between the suction air A2 that has been heated to a high temperature and high pressure and the cooling water, and cools this suction air A2 to about room temperature. Note that the air cooler 12 may have any configuration as long as it can cool the suction air A2 to about room temperature. For example, the air cooler 12 may cool the suction air A2 that has been heated to a high temperature and high pressure to about room temperature by cooling air instead of cooling water.

[0024] The suction air A2 that has been brought to about room temperature by the air cooler 12 is supplied to the heat exchanger 8. Then, the heat exchanger 8 exchanges heat between this suction air A2 at about room temperature and the suction air A2 immediately after being sucked from the cooling chamber 101 (the suction air A2 that has been brought to about room temperature by the air cooler 12 is pre-cooled).

[0025] The turbine 2 expands the suction air A2 that has been pre-cooled by the heat exchanger 8, and reduces the temperature and pressure of this suction air A2 (generates the cooling air A1). The turbine 2 is connected to the motor 14 by the other drive shaft 15b and is driven by the motor 14. The cooling air A1 generated by the turbine 2 flows through the air line 6 and is sent to the cooling chamber 101. The turbine 2 operates at a rotational speed corresponding to the rotational speed of the motor 14. In the present disclosure, it is described that the rotational speed of the turbine 2 is equal to the rotational speed of the motor 14.

[0026] The control device 4 controls the operation of the turbine 2. In one embodiment, the control device 4 is electrically connected to the motor 14 and controls the rotational speed of the turbine 2 via the motor 14. The control device 4 is a computer such as an electronic control unit, and includes a processor such as a CPU or GPU (not shown), a memory such as a ROM or RAM, and an I / O interface. The control device 4 realizes each functional unit included in the control device 4 by the processor operating (performing calculations, etc.) according to the instructions of the program loaded in the memory. With reference to FIG. 3, each functional unit of the control device 4 according to the first embodiment will be described. In some embodiments, the control device 4 is a cloud server provided in a cloud environment.

[0027] FIG. 3 is a schematic functional block diagram of the control device 4 according to the first embodiment. As shown in FIG. 3, the control device 4 includes a startup operation unit 20A.

[0028] In the first embodiment, as illustrated in FIG. 2, the cooling device 1A further includes an inlet temperature sensor 16 that measures the inlet temperature T1 of the turbine 2. The control device 4 is electrically connected to the inlet temperature sensor 16 and acquires the inlet temperature T1. When the cooling device 1A starts up, the startup operation unit 20A operates the turbine 2 at the first rotational speed X1 until the inlet temperature T1 of the turbine 2 drops below a preset inlet-side specified temperature TA. Then, when the inlet temperature T1 of the turbine 2 is less than the inlet-side specified temperature TA, the startup operation unit 20A operates the turbine 2 at a second rotational speed X2 that is greater than the first rotational speed X1. Note that the startup operation unit 20A can detect the startup of the cooling device 1A, and for example, detects that a power supply (not shown) has been turned on.

[0029] The operation of the startup operation unit 20A will be specifically described. When the cooling device 1A starts up, the startup operation unit 20A instructs the motor 14 to rotate at the first rotation speed X1. When the motor 14 receives the instruction PA including the first rotation speed X1 from the startup operation unit 20A, it rotates at the first rotation speed X1. Then, the turbine 2 also operates at the first rotation speed X1, and the cooling chamber 101 is gradually cooled. Then, when the inlet temperature T1 becomes lower than the inlet-side specified temperature TA, the startup operation unit 20A instructs the motor 14 to rotate at the second rotation speed X2. When the motor 14 receives the instruction PA including the second rotation speed X2 from the startup operation unit 20A, it rotates at the second rotation speed X2. Then, the turbine 2 also operates at the second rotation speed X2, and the cooling chamber 101 is further cooled. In the first embodiment, the second rotation speed X2 is, for example, the rated rotation speed of the turbine 2. The first rotation speed X1 is a low rotation speed such that the moisture contained in the suction air A2 supplied to the turbine 2 does not freeze. The inlet-side specified temperature TA is a temperature of -5 degrees or more and 10 degrees or less, for example, 0 degrees.

[0030] (Function and Effect) Before the cooling device 1 starts up, the air in the cooling chamber 101 may contain moisture. For this reason, when the cooling device 1 is started up, if the rotation speed of the turbine 2 is suddenly increased, the moisture contained in the air (suction air A2) sucked from the cooling chamber 101 may freeze inside the turbine 2. If icing occurs inside the turbine 2, the flow rate of the suction air A2 flowing through the turbine 2 decreases, leading to a performance degradation of the cooling device 1.

[0031] According to the first embodiment, when the cooling device 1A is started, the turbine 2 operates at the first rotational speed X1 until the inlet temperature T1 drops below the inlet-side specified temperature TA, and operates at the second rotational speed X2 when the inlet temperature T1 is less than the inlet-side specified temperature TA. Therefore, even if moisture contained in the suction air A2 condenses to form droplets in the turbine 2 while the turbine 2 is operating at the first rotational speed X1, these droplets can be arbitrarily processed before freezing. After the suction air A2 is dehydrated, the turbine 2 is operated at the second rotational speed X2 (rated operating speed). Therefore, the occurrence of icing in the turbine 2 is suppressed. Thus, it is possible to suppress a decrease in the performance of the cooling device 1A due to icing in the turbine 2 when starting.

[0032] Incidentally, as a method for processing droplets, for example, there is a method of guiding the droplets to the downstream side of the nozzle flow path 25 (described later) of the turbine 2 or the cooling chamber 101 by the suction air A2 or the cooling air A1 to freeze them. In some embodiments, the cooling device 1A is provided on the downstream side of the air line 6 with respect to the turbine 2 and includes an ice former that freezes moisture contained in the cooling air A1. In some embodiments, the turbine 2 is configured to drain droplets formed in the turbine 2.

[0033] Furthermore, according to the first embodiment, icing in the turbine 2 is suppressed by controlling the operation of the turbine 2, and no additional device for suppressing icing is provided. Therefore, it is possible to suppress an increase in the size of the cooling device 1A while suppressing a decrease in performance due to icing in the turbine 2 when starting. In particular, since the refrigerated container 100 limits the size of the cooling device 1A, the cooling device 1A according to the present disclosure is advantageous.

[0034] Furthermore, according to the cooling device 1A illustrated in FIG. 2, the cooling chamber 101 can be cooled more quickly compared to the cooling device 1C described later.

[0035] <Cooling device> (Configuration) The cooling device 1B(1) according to the second embodiment will be described. FIG. 4 is a diagram schematically showing the configuration of the cooling device 1B according to the second embodiment. FIG. 5 is a schematic functional block diagram of the control device 4 according to the second embodiment. The cooling device 1B according to the second embodiment is different from the cooling device 1A according to the first embodiment described above in that the operation of the turbine 2 is controlled based on the outlet temperature T2 of the turbine 2. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the detailed description thereof is omitted.

[0036] In the second embodiment, as illustrated in FIG. 4, the cooling device 1B includes an outlet temperature sensor 17 that measures the outlet temperature T2 of the turbine 2. The control device 4 is electrically connected to the outlet temperature sensor 17 and acquires the outlet temperature T2. As shown in FIG. 5, the control device 4 includes a startup operation unit 20B. When the cooling device 1 starts up, the startup operation unit 20B operates the turbine 2 at the first rotational speed X1 until the outlet temperature T2 drops below a preset outlet-side specified temperature TB, and operates the turbine 2 at the second rotational speed X2 when the outlet temperature T2 is less than the outlet-side specified temperature TB. Note that the startup operation unit 20B can detect the startup of the cooling device 1B. For example, it detects that a power source (not shown) has been turned on.

[0037] The operation of the startup operation unit 20B will be specifically described. When the cooling device 1A starts up, the startup operation unit 20B instructs the motor 14 to rotate at the first rotational speed X1. When the motor 14 receives the instruction PB including the first rotational speed X1 from the startup operation unit 20B, it rotates at the first rotational speed X1. Then, the turbine 2 also operates at the first rotational speed X1, and the cooling chamber 101 is gradually cooled. Then, when the outlet temperature T2 becomes lower than the outlet-side specified temperature TB, the startup operation unit 20B instructs the motor 14 to rotate at the second rotational speed X2. When the motor 14 receives the instruction PB including the second rotational speed X2 from the startup operation unit 20B, it rotates at the second rotational speed X2. Then, the turbine 2 also operates at the second rotational speed X2, and the cooling chamber 101 is further cooled. In the second embodiment, the second rotational speed X2 is, for example, the rated rotational speed of the turbine 2. The first rotational speed X1 is a low rotational speed such that the moisture contained in the suction air A2 supplied to the turbine 2 does not freeze. The outlet-side specified temperature TB is a temperature of -5 degrees or more and 10 degrees or less, for example, 0 degrees.

[0038] (Function and Effect) According to the second embodiment, when the cooling device 1B starts up, the turbine 2 operates at the first rotational speed X1 until the outlet temperature T2 drops below the outlet-side specified temperature TB, and operates at the second rotational speed X2 when the outlet temperature T2 is lower than the outlet-side specified temperature TB. Therefore, even if droplets are formed in the turbine 2 due to the condensation of the moisture contained in the suction air A2 while the turbine 2 is operating at the first rotational speed X1, these droplets can be arbitrarily processed before freezing. After the suction air A2 is dehydrated, the turbine 2 is operated at the second rotational speed X2 (rated operating speed). Therefore, the occurrence of icing in the turbine 2 is suppressed. Thus, it is possible to suppress a decrease in the performance of the cooling device 1B due to icing in the turbine 2 when starting up. Note that a specific example of the method for processing the droplets has been described above.

[0039] Furthermore, according to the cooling device 1B illustrated in FIG. 4, icing inside the turbine 2 is suppressed by controlling the operation of the turbine 2, and no additional device for suppressing new icing is provided. Therefore, while suppressing an increase in the size of the cooling device 1B, it is possible to suppress a decrease in performance due to icing inside the turbine 2 when starting up. In particular, since the refrigerated container 100 limits the size of the cooling device 1B, the cooling device 1B according to the present disclosure is advantageous.

[0040] Furthermore, according to the cooling device 1B illustrated in FIG. 4, compared with the cooling device 1C described later, the cooling chamber 101 can be cooled rapidly.

[0041] <Cooling device> (Configuration) The cooling device 1C(1) according to the third embodiment will be described. FIG. 6 is a diagram schematically showing the configuration of the cooling device 1C according to the third embodiment. FIG. 7 is a schematic functional block diagram of the control device 4 according to the third embodiment. In the cooling device 1C according to the third embodiment, the operation of the turbine 2 is controlled based on each of the inlet temperature T1 of the turbine 2 and the outlet temperature T2 of the turbine 2, which is different from the cooling device 1A according to the first embodiment and the cooling device 1B according to the second embodiment described above. In the third embodiment, the same components as those in the first embodiment and the second embodiment are denoted by the same reference numerals, and detailed descriptions thereof are omitted.

[0042] In the third embodiment, as illustrated in FIG. 6, the cooling device 1C includes an inlet temperature sensor 16 and an outlet temperature sensor 17. The control device 4 is electrically connected to each of the inlet temperature sensor 16 and the outlet temperature sensor 17, and acquires the inlet temperature T1 and the outlet temperature T2. As shown in FIG. 7, the control device 4 includes a startup operation unit 20C. When the cooling device 1C starts up, the startup operation unit 20C operates the turbine 2 at the first rotational speed X1 until the outlet temperature T2 drops below the outlet-side specified temperature TB. Then, when the outlet temperature T2 is less than the outlet-side specified temperature TB, the turbine 2 is operated at the second rotational speed X2. Then, until the inlet temperature T1 drops below the inlet-side specified temperature TA, the turbine 2 is operated at the second rotational speed X2, and when the inlet temperature T1 is less than the inlet-side specified temperature TA, the turbine is operated at the third rotational speed X3, which is greater than the second rotational speed X2. Note that the startup operation unit 20C can detect the startup of the cooling device 1C. For example, the startup operation unit 20C detects that a power supply (not shown) has been turned on.

[0043] The operation of the startup operation unit 20C will be specifically described. When the cooling device 1A starts up, the startup operation unit 20C instructs the motor 14 to rotate at the first rotational speed X1. When the motor 14 receives the instruction PC including the first rotational speed X1 from the startup operation unit 20C, the motor 14 rotates at the first rotational speed X1. Then, the turbine 2 is also operated at the first rotational speed X1, and the cooling chamber 101 is gradually cooled. Then, when the outlet temperature T2 becomes less than the outlet-side specified temperature TB, the startup operation unit 20C instructs the motor 14 to rotate at the second rotational speed X2. When the motor 14 receives the instruction PC including the second rotational speed X2 from the startup operation unit 20C, the motor 14 rotates at the second rotational speed X2. Then, the turbine 2 is also operated at the second rotational speed X2, and the cooling chamber 101 is further cooled. The startup operation unit 20C maintains a state in which the turbine 2 is operated at the second rotational speed X2 until the inlet temperature T1 drops below the inlet-side specified temperature TA. Then, when the inlet temperature T1 becomes less than the inlet-side specified temperature TA, the startup operation unit 20C instructs the motor 14 to rotate at the third rotational speed X3. When the motor 14 receives the instruction PC including the third rotational speed X3 from the startup operation unit 20C, the motor 14 rotates at the third rotational speed X3. Then, the turbine 2 is also operated at the third rotational speed X3, and the cooling chamber 101 is further cooled.

[0044] In the third embodiment, the third rotational speed X3 is, for example, the rated rotational speed of the turbine 2. The first rotational speed X1 is a low rotational speed such that the moisture contained in the suction air A2 supplied to the turbine 2 does not freeze. The second rotational speed X2 is a medium rotational speed that is smaller than the third rotational speed X3 and larger than the first rotational speed X1. The inlet-side specified temperature TA is a temperature of -5 degrees or more and 10 degrees or less, for example, 0 degrees. The outlet-side specified temperature TB is a temperature of -5 degrees or more and 10 degrees or less, for example, 0 degrees.

[0045] (Function and Effect) According to the cooling device 1C (third embodiment) illustrated in FIG. 6, when the cooling device 1C is started, the turbine 2 operates at the first rotational speed X1 until the outlet temperature T2 drops below the outlet-side specified temperature TB, and operates at the second rotational speed X2 when the outlet temperature T2 is less than the outlet-side specified temperature TB. Further, the turbine 2 maintains operation at the second rotational speed X2 until the inlet temperature T1 drops below the inlet-side specified temperature TA, and operates at the third rotational speed X3 when the inlet temperature T1 is less than the inlet-side specified temperature TA. For this reason, even if moisture contained in the suction air A2 condenses to form droplets in the turbine 2 while the turbine 2 is operating at the first rotational speed X1 or the second rotational speed X2, these droplets can be arbitrarily treated before freezing. Then, after the suction air A2 is dehydrated, the turbine 2 is operated at the third rotational speed X3 (rated operating speed). For this reason, the occurrence of icing in the turbine 2 is suppressed. Therefore, it is possible to suppress a decrease in the performance of the cooling device 1C due to icing in the turbine 2 when starting. Note that a specific example of the method for treating droplets has been described above.

[0046] Furthermore, according to the cooling device 1C illustrated in FIG. 6, icing in the turbine 2 is suppressed by controlling the operation of the turbine 2, and no additional device for newly suppressing icing is provided. For this reason, it is possible to suppress an increase in the size of the cooling device 1C and suppress a decrease in performance due to icing in the turbine 2 when starting. In particular, since the refrigerated container 100 limits the size of the cooling device 1C, the cooling device 1C according to the present disclosure is advantageous.

[0047] Furthermore, according to the cooling device 1C illustrated in FIG. 6, the turbine 2 is operated in three stages (low speed, medium speed, and high speed) from the first rotational speed X1 to the third rotational speed X3 according to the outlet temperature T2 and the inlet temperature T1. Therefore, as compared with each of the cooling device 1A according to the first embodiment and the cooling device 1B according to the second embodiment, the amount of droplets formed by the condensation of the moisture contained in the suction air A2 can be increased. That is, it is possible to further suppress the performance degradation due to icing in the turbine 2 when starting.

[0048] <turbine> (Configuration) An example of the specific configuration of the turbine 2 will be described. FIG. 8 is a diagram schematically showing the configuration of the turbine 2 according to one embodiment. As illustrated in FIG. 8, the turbine 2 includes a turbine rotor 22, a scroll flow path forming portion 24 that forms a scroll flow path 23 on the outer peripheral side of the turbine rotor 22, and a nozzle flow path forming portion 26 that forms a nozzle flow path 25 for guiding the suction air A2 from the scroll flow path 23 to the turbine rotor 22.

[0049] In the form illustrated in FIG. 8, the turbine 2 includes a casing 21 that rotatably houses the turbine rotor 22. This casing 21 has a scroll flow path forming portion 24, a nozzle flow path forming portion 26, and a discharge flow path forming portion 44. The turbine rotor 22 includes a plurality of moving blades 35 that rotate by receiving the flow of the suction air A2. The turbine rotor 22 is connected to the drive shaft 15b.

[0050] Hereinafter, the direction in which the axis O of the turbine rotor 22 extends is defined as the axial direction D1, the side on the drive shaft 15b side in the axial direction D1 is defined as the rear end side of the axial direction D1, and the side opposite to the rear end side is defined as the front end side of the axial direction D1. Further, the direction orthogonal to the axis O is defined as the radial direction D2, the direction approaching the axis O in the radial direction D2 is defined as the inner side of the radial direction D2, and the direction away from the axis O is defined as the outer side of the radial direction D2.

[0051] The scroll flow path forming portion 24 has a scroll flow path surface 30 which is the surface facing the scroll flow path 23. The scroll flow path 23 is a spiral flow path for guiding the suction air A2 flowing into the turbine 2 to the turbine rotor 22. The scroll flow path 23 extends along the circumferential direction D3 around the axis O on the outer side in the radial direction D2 (the outer peripheral side of the turbine rotor 22) than the turbine rotor 22.

[0052] The nozzle flow path forming portion 26 has a nozzle flow path surface 32 which is the surface facing the nozzle flow path 25. The nozzle flow path 25 is a flow path for guiding the suction air A2 from the scroll flow path 23 to the turbine rotor 22 disposed on the inner side in the radial direction D2 than the scroll flow path 23. The nozzle flow path 25 is formed between the scroll flow path 23 and the turbine rotor 22 so as to surround the outer side in the radial direction D2 of the turbine rotor 22. The suction air A2 flowing into the turbine 2 is guided to the turbine rotor 22 from the outer side in the radial direction D2 of the turbine rotor 22 after flowing through the scroll flow path 23 and the nozzle flow path 25 in this order.

[0053] The discharge flow path forming portion 44 has an outlet 46 formed at the end on the tip side in the axial direction D1 for discharging the cooling air A1 from the turbine 2. The discharge flow path forming portion 44 has a discharge flow path 45 formed inside for sending the suction air A2 (cooling air A1) that has rotationally driven the turbine rotor 22 to the outlet 46.

[0054] In one embodiment, each of the scroll flow path forming portion 24 and the nozzle flow path forming portion 26 has water repellency. FIG. 9 is a diagram for explaining "having water repellency" in the present disclosure. As shown in FIG. 9, in a state where a pure water droplet 202 adheres to an object 200 to be measured (evaluated) for water repellency, when a tangent line L of the surface 203 of the droplet 202 passing through a point P1 where the surface 201 of the object 200 and the surface 203 of the droplet 202 are in contact is defined, an angle on the side where the droplet 202 exists among the angles formed by the tangent line L and the surface 201 of the object 200 is defined as a contact angle θ. "Having water repellency" in the present disclosure means that the contact angle θ is 90 degrees or more. Note that the method for measuring this contact angle θ is not particularly limited, and for example, it may be measured using a contact angle meter (manufactured by Kyowa Interface Science Co., Ltd., product name: fully automatic contact angle meter DMo-902).

[0055] In one embodiment, each of the scroll flow path forming portion 24 and the nozzle flow path forming portion 26 is made of an aluminum alloy. In one embodiment, the scroll flow path forming portion 24 is subjected to a water repellent coating treatment on the scroll flow path surface 30, and a water repellent layer M is formed. Further, the nozzle flow path forming portion 26 is subjected to a water repellent coating treatment on the nozzle flow path surface 32, and a water repellent layer M is formed. The casing 21 is subjected to a water repellent coating treatment on the entire surface facing the flow path through which the suction air A2 flows, and a water repellent layer M is formed. That is, the water repellent layer M is also formed on the surface facing the discharge flow path 45 of the discharge flow path forming portion 44.

[0056] FIG. 10 is an enlarged perspective view of a part of the scroll flow path forming portion 24 according to an embodiment. In one embodiment, as illustrated in FIG. 10, the scroll flow path forming portion 24 is formed with a scroll flow path groove 36 extending along the flow direction Da of the suction air A2 flowing through the scroll flow path 23 on the scroll flow path surface 30. And the scroll flow path groove 36 has a width W1 of 0.01 mm or more and 0.5 mm or less. This scroll flow path groove 36 is formed so as to extend while being inclined at an angle within ±45 degrees with respect to the flow direction Da of the suction air A2 flowing through the scroll flow path 23. In the form illustrated in FIG. 10, the scroll flow path forming portion 24 is formed with a plurality of scroll flow path grooves 36 on the scroll flow path surface 30. The plurality of scroll flow path grooves 36 are arranged at intervals along a direction intersecting the flow direction Da of the suction air A2 flowing through the scroll flow path 23. If the size (pitch) of this interval is W3, then 0.9×W1 < W3 < 1.1×W1 is satisfied.

[0057] FIG. 11 is an enlarged perspective view of a part of the nozzle flow path forming portion 26 according to an embodiment. In one embodiment, as illustrated in FIG. 11, the nozzle flow path forming portion 26 is formed with a nozzle flow path groove 38 extending along the flow direction Db of the suction air A2 flowing through the nozzle flow path 25 on the nozzle flow path surface 32. And the nozzle flow path groove 38 has a width W2 of 0.01 mm or more and 0.5 mm or less. This nozzle flow path groove 38 is formed so as to extend while being inclined at an angle within ±45 degrees with respect to the flow direction Db of the suction air A2 flowing through the nozzle flow path 25. In the form illustrated in FIG. 11, the nozzle flow path forming portion 26 is formed with a plurality of nozzle flow path grooves 38 on the nozzle flow path surface 32. The plurality of nozzle flow path grooves 38 are arranged at intervals along a direction intersecting the flow direction Db of the suction air A2 flowing through the nozzle flow path 25. If the size (pitch) of this interval is W4, then 0.9×W2 < W4 < 1.1×W4 is satisfied.

[0058] FIG. 12 is a diagram schematically showing the internal configuration of the turbine 2 according to one embodiment, and is a view seen from the tip side in the axial direction D1. In one embodiment, as illustrated in FIG. 12, the turbine 2 further includes a plurality of nozzle vanes 40 arranged at intervals in the circumferential direction D3 in the nozzle flow path 25. The nozzle vane 40 is subjected to a water-repellent coating treatment on the surface 42 facing the nozzle flow path 25, and a water-repellent layer M is formed. However, the nozzle vane 40 is not subjected to groove processing for forming grooves on the surface 42 facing the nozzle flow path 25. In one embodiment, the number of the plurality of nozzle vanes 40 is smaller than the number of the plurality of rotor blades 35.

[0059] (Function and Effect) Among the flow paths through which the suction air A2 flows, the nozzle flow path 25 has a relatively narrow flow path cross-section, and the influence when droplets freeze is large. Therefore, it is desirable to actively suppress icing on the nozzle flow path 25. The discharge flow path 45 has a larger flow path cross-section than the nozzle flow path 25. Therefore, according to the turbine 2 according to one embodiment, since each of the scroll flow path forming portion 24 and the nozzle flow path forming portion 26 has water repellency, even if moisture contained in the suction air A2 condenses and droplets are formed in the scroll flow path 23 and the nozzle flow path 25, these droplets can be guided to the discharge flow path 45, and icing on the nozzle flow path 25 can be suppressed.

[0060] According to the turbine 2 according to one embodiment, since each of the scroll flow path forming portion 24 and the nozzle flow path forming portion 26 is made of an aluminum alloy, it can have water repellency. Note that the present disclosure is not limited to the case where each of the scroll flow path forming portion 24 and the nozzle flow path forming portion 26 is made of an aluminum alloy. In some embodiments, one of the scroll flow path forming portion 24 and the nozzle flow path forming portion 26 is made of an aluminum alloy. Each of the scroll flow path forming portion 24 and the nozzle flow path forming portion 26 may be made of a material other than an aluminum alloy and have water repellency.

[0061] According to the turbine 2 according to one embodiment, a water-repellent layer M is formed on each of the scroll flow path surface 30 and the nozzle flow path surface 32. Therefore, each of the scroll flow path surface 30 and the nozzle flow path surface 32 can have water repellency. Note that the present disclosure is not limited to the formation of the water-repellent layer M on each of the scroll flow path surface 30 and the nozzle flow path surface 32. In some embodiments, the water-repellent layer M is formed on one of the scroll flow path surface 30 and the nozzle flow path surface 32.

[0062] According to the turbine 2 according to one embodiment, the scroll flow path forming portion 24 is made of an aluminum alloy, and a water-repellent layer M is formed on the scroll flow path surface 30, so that it can have higher water repellency compared with the case of having either one. However, the present disclosure is not limited to this form. In some embodiments, the scroll flow path forming portion 24 is made of an aluminum alloy, but the water-repellent layer M is not formed on the scroll flow path surface 30. In some embodiments, the scroll flow path forming portion 24 is made of a material having lower water repellency than the aluminum alloy, and the water-repellent layer M is formed on the scroll flow path surface 30. The same applies to the nozzle flow path forming portion 26.

[0063] Generally, it is known that by forming grooves on a water-repellent surface, the water repellency can be enhanced (to have super water repellency). According to the turbine 2 according to one embodiment, scroll flow path grooves 36 are formed on the scroll flow path surface 30, and nozzle flow path grooves 38 are formed on the nozzle flow path surface 32. Therefore, each of the scroll flow path surface 30 and the nozzle flow path surface 32 can enhance the water repellency.

[0064] When the turbine 2 has the nozzle vanes 40, if grooves are formed on the surface of the nozzle vanes 40 to enhance the water repellency of the nozzle vanes 40, there is a risk of causing a performance degradation of the nozzle vanes 40. According to the turbine 2 according to one embodiment, the nozzle vanes 40 are not grooved but are subjected to a water-repellent coating treatment, so that they can have water repellency while suppressing performance degradation and an increase in manufacturing cost.

[0065] According to the turbine 2 according to an embodiment, the number of the plurality of nozzle vanes 40 is smaller than the number of the plurality of rotor blades 35. Therefore, the number of the nozzle vanes 40 to be subjected to the water-repellent coating treatment can be reduced, and the manufacturing cost can be reduced. Further, the total area (splash area) of the nozzle vanes 40 facing the nozzle flow path 25 can be reduced, and icing in the nozzle flow path 25 can be further suppressed.

[0066] In the turbine 2 according to an embodiment, both the scroll flow path forming portion 24 and the nozzle flow path forming portion 26 are configured to have water repellency, but the present disclosure is not limited to this form. Only the nozzle flow path forming portion 26 may be configured to have water repellency. In some embodiments, the nozzle flow path forming portion 26 is made of an aluminum alloy, and a nozzle flow path groove 38 having a width extending along the flow direction Db of the suction air A2 flowing through the nozzle flow path 25 on the nozzle flow path surface 32 and having a size of 0.01 mm or more and 0.5 mm or less is formed, and the nozzle flow path surface 32 is subjected to a water-repellent coating treatment. Further, the nozzle vane 40 is subjected to a water-repellent coating treatment on the surface facing the nozzle flow path 25, and no grooving is performed on the surface facing the nozzle flow path 25.

[0067] The nozzle flow path 25 has a narrower flow path cross section than other flow paths formed in the turbine 2. Therefore, it is important to guide the droplets in the nozzle flow path 25 to the downstream side of the nozzle flow path 25 to suppress icing in the nozzle flow path 25. According to the above-described configuration, since the nozzle flow path forming portion 26 is made of an aluminum alloy and the nozzle flow path surface 32 is subjected to a water-repellent coating treatment, the nozzle flow path surface 32 has high water repellency. Further, since the nozzle vane 40 is not grooved but is subjected to a water-repellent coating treatment, it has water repellency while suppressing a decrease in performance and an increase in manufacturing cost. Therefore, the droplets in the nozzle flow path 25 can be guided to the downstream side of the nozzle flow path 25, and icing in the nozzle flow path 25 can be suppressed.

[0068] <Operation method of the cooling device> FIG. 13 is a flowchart showing an operation method of the cooling device 1 according to an embodiment. The cooling device 1 includes a turbine 2 that expands the air sucked from the cooling chamber 101 to cool the cooling chamber 101 of the refrigerated container 100. As shown in FIG. 13, in the operation method of the cooling device 1 according to an embodiment, when the cooling device 1 starts up, the turbine 2 is operated at the first rotational speed X1 until the inlet temperature T1 of the turbine 2 drops below the inlet-side specified temperature TA (0 degrees), and when the inlet temperature T1 of the turbine 2 is less than the inlet-side specified temperature TA, the turbine is operated at the second rotational speed X2, including a first startup operation step SA. The operation method of the cooling device 1 according to this embodiment starts when the cooling device 1 starts up and ends when the turbine 2 is operated at the second rotational speed X2.

[0069] The first startup operation step SA includes a low-speed operation step SA1, an inlet temperature determination step SA2, and a high-speed operation step SA3. In the low-speed operation step SA1, the turbine 2 is operated at the first rotational speed X1. When the cooling device 1 starts up, the low-speed operation step SA1 is executed. In the inlet temperature determination step SA2, after the execution of the low-speed operation step SA1, it is determined whether the inlet temperature T1 of the turbine 2 is less than the inlet-side specified temperature TA. If the inlet temperature T1 of the turbine 2 is less than the inlet-side specified temperature TA (SA2: Yes), the process proceeds to the high-speed operation step SA3. If the inlet temperature T1 of the turbine 2 is greater than or equal to the inlet-side specified temperature TA (SA2: No), the process returns to the low-speed operation step SA1. In the high-speed operation step SA3, the turbine 2 is operated at the second rotational speed X2. When the high-speed operation step SA3 is executed, the operation method of the cooling device 1 according to an embodiment ends.

[0070] FIG. 14 is a flowchart showing a method of operating the cooling device 1 according to another embodiment. The cooling device 1 includes a turbine 2 that expands the air sucked from the cooling chamber 101 to cool the cooling chamber 101 of the refrigerated container 100. As shown in FIG. 14, in the method of operating the cooling device 1 according to another embodiment, when the cooling device 1 starts up, the turbine 2 is operated at the first rotational speed X1 until the outlet temperature T2 of the turbine 2 drops below the outlet-side specified temperature TB (0 degrees), and when the outlet temperature T2 of the turbine 2 is less than the outlet-side specified temperature TB, the turbine 2 is operated at the second rotational speed X2 in a second startup operation step SB. The method of operating the cooling device 1 according to this another embodiment starts when the cooling device 1 starts up and ends when the turbine 2 is operated at the second rotational speed X2.

[0071] The second startup operation step SB includes a low-speed operation step SB1, an outlet temperature determination step SB2, and a high-speed operation step SB3. In the low-speed operation step SB1, the turbine 2 is operated at the first rotational speed X1. When the cooling device 1 starts up, the low-speed operation step SB1 is executed. In the outlet temperature determination step SB2, after the execution of the low-speed operation step SB1, it is determined whether the outlet temperature T2 of the turbine 2 is less than the outlet-side specified temperature TB. If the outlet temperature T2 of the turbine 2 is less than the outlet-side specified temperature TB (SB2: Yes), the process proceeds to the high-speed operation step SB3. If the outlet temperature T2 of the turbine 2 is greater than or equal to the outlet-side specified temperature TB (SA2: No), the process returns to the low-speed operation step SB1. In the high-speed operation step SB3, the turbine 2 is operated at the second rotational speed X2. When the high-speed operation step SB3 is executed, the method of operating the cooling device 1 according to another embodiment ends.

[0072] FIG. 15 is a flowchart showing a method of operating the cooling device 1 according to still another embodiment. The cooling device 1 includes a turbine 2 that expands the air sucked from the cooling chamber 101 to cool the cooling chamber 101 of the refrigerated container 100. As shown in FIG. 15, the method of operating the cooling device 1 according to still another embodiment is such that when the cooling device 1 is started, the turbine 2 is operated at the first rotational speed X1 until the outlet temperature T2 of the turbine 2 drops below the outlet-side specified temperature TB (0 degrees), and when the outlet temperature T2 of the turbine 2 is less than the outlet-side specified temperature TB, the turbine 2 is operated at the second rotational speed X2. The turbine 2 is operated at the second rotational speed X2 until the inlet temperature T1 of the turbine 2 drops below the inlet-side specified temperature TA (0 degrees), and when the inlet temperature T1 of the turbine 2 is less than the inlet-side specified temperature TA, the turbine 2 is operated at the third rotational speed X3. The method includes a third startup operation step SC of operating the turbine 2 at the third rotational speed X3.

[0073] The third startup operation step SC includes a low-speed operation step SC1, an outlet temperature determination step SC2, a medium-speed operation step SC3, an inlet temperature determination step SC4, and a high-speed operation step SC5. In the low-speed operation step SC1, the turbine 2 is operated at the first rotational speed X1. When the cooling device 1 is started, the low-speed operation step SC1 is executed. In the outlet temperature determination step SC2, after the execution of the low-speed operation step SC1, it is determined whether the outlet temperature T2 of the turbine 2 is less than the outlet-side specified temperature TB. If the outlet temperature T2 of the turbine 2 is less than the outlet-side specified temperature TB (SC2: Yes), the process proceeds to the medium-speed operation step SC3. If the outlet temperature T2 of the turbine 2 is greater than or equal to the outlet-side specified temperature TB (SC2: No), the process returns to the low-speed operation step SC1. In the medium-speed operation step SC3, the turbine 2 is operated at the second rotational speed X2. In the inlet temperature determination step SC4, after the execution of the medium-speed operation step SC3, it is determined whether the inlet temperature T1 of the turbine 2 is less than the inlet-side specified temperature TA. If the inlet temperature T1 of the turbine 2 is less than the inlet-side specified temperature TA (SC4: Yes), the process proceeds to the high-speed operation step SC5. If the inlet temperature T1 of the turbine 2 is greater than or equal to the inlet-side specified temperature TA (SC4: No), the process returns to the medium-speed operation step SC3. In the high-speed operation step SC5, the turbine 2 is operated at the third rotational speed X3. When the high-speed operation step SC5 is executed, the operation method of the cooling device 1 according to another embodiment ends.

[0074] The content described in each of the above embodiments is understood as follows, for example.

[0075] [1] The cooling device (1A) according to the present disclosure is a cooling device for cooling the cooling chamber (101) of the refrigerated container (100), a turbine (2) that expands the air (A2) sucked from the cooling chamber, and a control device (4) that controls the operation of the turbine, wherein the control device When the cooling device is activated, the turbine is operated at a first rotational speed (X1) until the inlet temperature (T1) of the turbine drops below a preset inlet-side specified temperature (TA), and when the inlet temperature of the turbine is lower than the inlet-side specified temperature, the turbine is operated at a second rotational speed (X2) greater than the first rotational speed. The starting operation unit (20A) is included.

[0076] Before the cooling device is activated, the air in the cooling chamber may contain moisture. Therefore, when the cooling device is activated, if the rotational speed of the turbine is suddenly increased, the moisture contained in the air sucked from the cooling chamber may freeze inside the turbine. When ice forms inside the turbine, the flow rate of the air flowing through the turbine decreases, leading to a deterioration in the performance of the cooling device. According to the configuration described in [1] above, when the cooling device is activated, the turbine operates at the first rotational speed until the inlet temperature of the turbine drops below the inlet-side specified temperature, and operates at the second rotational speed when the inlet temperature of the turbine is lower than the inlet-side specified temperature. Therefore, by appropriately setting the inlet-side specified temperature, even if the moisture contained in the air sucked from the cooling chamber condenses to form droplets, icing inside the turbine can be suppressed. Thus, it is possible to suppress a deterioration in the performance of the cooling device due to icing inside the turbine when it is activated.

[0077] Furthermore, according to the configuration described in [1] above, icing inside the turbine is suppressed by controlling the operation of the turbine, and no additional device for suppressing icing is provided. Therefore, while suppressing an increase in the size of the cooling device, it is possible to suppress a deterioration in performance due to icing inside the turbine when it is activated. In particular, since a refrigerated container limits the size of the cooling device, the cooling device according to the present disclosure is advantageous.

[0078] [2] The cooling device (1B) according to the present disclosure is a cooling device for cooling the cooling chamber (101) of a refrigerated container (100), a turbine (2) that expands the air (A2) sucked from the cooling chamber, and a control device (4) that controls the operation of the turbine, and is provided with the control device is When the cooling device is activated, the turbine is operated at a first rotational speed (X1) until the outlet temperature (T2) of the turbine drops below a preset outlet-side specified temperature (TB), and when the outlet temperature of the turbine is less than the outlet-side specified temperature, the turbine is operated at a second rotational speed (X2) greater than the first rotational speed. It includes a startup operation unit (20B).

[0079] According to the configuration described in [2] above, when the cooling device is activated, the turbine operates at the first rotational speed until the outlet temperature of the turbine drops below the outlet-side specified temperature, and operates at the second rotational speed when the outlet temperature of the turbine is less than the outlet-side specified temperature. Therefore, by appropriately setting the outlet-side specified temperature, even if moisture contained in the air sucked from the cooling chamber condenses to form droplets, icing inside the turbine can be suppressed. Thus, it is possible to suppress a decrease in the performance of the cooling device due to icing inside the turbine when starting up.

[0080] Furthermore, according to the configuration described in [2] above, icing inside the turbine is suppressed by controlling the operation of the turbine, and no additional device for suppressing icing is installed. Therefore, while suppressing an increase in the size of the cooling device, it is possible to suppress a decrease in performance due to icing inside the turbine when starting up. In particular, since a refrigerated container limits the size of the cooling device, the cooling device according to the present disclosure is advantageous.

[0081] [3] The cooling device (1C) according to the present disclosure is a cooling device for cooling a cooling chamber (101) of a refrigerated container (100), a turbine (2) that expands air (A2) sucked from the cooling chamber, and a control device (4) that controls the operation of the turbine, wherein the control device, When the cooling device is started, the turbine is operated at a first rotational speed (X1) until the outlet temperature (T2) of the turbine drops below a preset outlet-side specified temperature (TB). When the outlet temperature of the turbine is less than the outlet-side specified temperature, the turbine is operated at a second rotational speed (X2) greater than the first rotational speed. The turbine is operated at the second rotational speed until the inlet temperature (T1) of the turbine drops below a preset inlet-side specified temperature (TA). When the inlet temperature of the turbine is less than the inlet-side specified temperature, the turbine is operated at a third rotational speed (X3) greater than the second rotational speed. The starting operation unit (20C) is included.

[0082] According to the configuration described in [3] above, when the cooling device is started, the turbine is operated at the first rotational speed until the outlet temperature of the turbine drops below the outlet-side specified temperature, and is operated at the second rotational speed when the outlet temperature of the turbine is less than the outlet-side specified temperature. Further, the turbine is operated at the second rotational speed until the inlet temperature of the turbine drops below the inlet-side specified temperature, and is operated at the third rotational speed when the inlet temperature of the turbine is less than the inlet-side specified temperature. Therefore, by appropriately setting each of the outlet-side specified temperature and the inlet-side specified temperature, even if moisture contained in the air sucked from the cooling chamber condenses to form droplets, icing inside the turbine can be suppressed. Thus, it is possible to suppress a decrease in the performance of the cooling device due to icing inside the turbine when starting.

[0083] Furthermore, according to the configuration described in [3] above, icing inside the turbine is suppressed by controlling the operation of the turbine, and no additional device for suppressing icing is provided. Therefore, it is possible to suppress an increase in the size of the cooling device and suppress a decrease in performance due to icing inside the turbine when starting. In particular, since the refrigerated container limits the size of the cooling device, the cooling device according to the present disclosure is advantageous.

[0084] Furthermore, according to the configuration described in [3] above, since the turbine is operated in three stages from the first rotational speed to the third rotational speed according to the outlet temperature and the inlet temperature of the turbine, compared with each of [1] and [2] above, the amount of droplets (hereinafter referred to as droplets) formed by the condensation of moisture contained in the air sucked from the cooling chamber can be increased.

[0085] [4] In some embodiments, in the configuration described in any one of [1] to [3] above, the turbine is, a turbine rotor (22), a scroll flow path forming portion (24) that forms a scroll flow path (23) on the outer peripheral side of the turbine rotor, and a nozzle flow path forming portion (26) that forms a nozzle flow path (25) for guiding the air from the scroll flow path to the turbine rotor, and each of the scroll flow path forming portion and the nozzle flow path forming portion has water repellency.

[0086] The nozzle flow path has a narrow flow path cross section, and the influence when droplets freeze is large. For this reason, it is desirable to actively suppress ice adhesion to the nozzle flow path. According to the configuration described in [4] above, since each of the scroll flow path forming portion and the nozzle flow path forming portion has water repellency, droplets can be guided to the downstream side of the turbine rather than the nozzle flow path, and ice adhesion to the nozzle flow path can be suppressed.

[0087] [5] In some embodiments, in the configuration described in [4] above, each of the scroll flow path forming portion and the nozzle flow path forming portion is made of an aluminum alloy.

[0088] According to the configuration described in [5] above, each of the scroll flow path forming portion and the nozzle flow path forming portion can have water repellency.

[0089] [6] In some embodiments, in the configuration described in [4] or [5] above, The scroll flow path forming portion is subjected to a water-repellent coating treatment on the surface (30) facing the scroll flow path. The nozzle flow path forming portion is subjected to a water-repellent coating treatment on the surface (32) facing the nozzle flow path.

[0090] According to the configuration described in [6] above, each of the surface facing the scroll flow path and the surface facing the nozzle flow path can have water repellency.

[0091] [7] In some embodiments, in the configuration described in any one of [4] to [6] above, the scroll flow path forming portion has a scroll flow path groove (36) formed on the surface facing the scroll flow path and extending along the flow direction (Da) of the air flowing through the scroll flow path. The scroll flow path groove has a width (W1) of 0.01 mm or more and 0.5 mm or less.

[0092] Generally, it is known that by forming grooves on a water-repellent surface, the water repellency can be enhanced (to have super water repellency). According to the configuration described in [7] above, the water repellency of the surface facing the scroll flow path can be further enhanced.

[0093] [8] In some embodiments, in the configuration described in any one of [4] to [7] above, the nozzle flow path forming portion has a nozzle flow path groove (38) formed on the surface facing the nozzle flow path and extending along the flow direction (Db) of the air flowing through the nozzle flow path. The nozzle flow path groove has a width (W2) of 0.01 mm or more and 0.5 mm or less.

[0094] According to the configuration described in [8] above, the water repellency of the surface facing the nozzle flow path can be further enhanced.

[0095] [9] In some embodiments, in the configuration described in any one of [4] to [8] above, The turbine further includes a plurality of nozzle vanes (40) arranged at intervals in the circumferential direction (D3) of the turbine rotor in the nozzle flow path. The nozzle vanes are subjected to a water-repellent coating treatment on the surface facing the nozzle flow path and are not subjected to grooving for forming grooves on the surface facing the nozzle flow path.

[0096] According to the configuration described in [9] above, a turbine having nozzle vanes can be employed. Further, since the nozzle vanes are not grooved but are subjected to a water-repellent coating treatment, water repellency can be achieved while suppressing a decrease in performance and an increase in manufacturing cost.

[0097]

[10] In some embodiments, in the configuration described in [9] above, The turbine rotor includes a plurality of moving blades (35), The number of the plurality of nozzle vanes is smaller than the number of the plurality of moving blades.

[0098] According to the configuration described in

[10] above, the number of nozzle vanes to be subjected to the water-repellent coating treatment can be reduced, and the manufacturing cost can be reduced. Further, the total area (wetted area) of the nozzle vanes facing the nozzle flow path can be reduced, and icing on the nozzle flow path can be further suppressed.

[0099]

[11] In some embodiments, in the configuration described in any one of [1] to [3] above, The turbine is a turbine rotor, a scroll flow path forming portion that forms a scroll flow path on the outer peripheral side of the turbine rotor, a nozzle flow path forming portion that forms a nozzle flow path for guiding the air from the scroll flow path to the turbine rotor, and a plurality of nozzle vanes arranged at intervals in the circumferential direction of the turbine rotor in the nozzle flow path. The nozzle flow path forming portion is made of an aluminum alloy. The nozzle flow path forming portion is formed with a nozzle flow path groove having a width extending along the flow direction of the air flowing through the nozzle flow path and having a size of 0.01 mm or more and 0.5 mm or less on the surface facing the nozzle flow path, and the surface facing the nozzle flow path is subjected to a water repellent coating treatment. The nozzle vane is subjected to a water repellent coating treatment on the surface facing the nozzle flow path, and groove processing for forming a groove is not performed on the surface facing the nozzle flow path.

[0100] The nozzle flow path has a narrower flow path cross section compared to other flow paths formed in the turbine. For this reason, it is important to guide the droplets in the nozzle flow path to the downstream side of the nozzle flow path and suppress icing on the nozzle flow path. According to the configuration described in the above

[11] , the nozzle flow path forming portion is made of an aluminum alloy and the surface facing the nozzle flow path is subjected to a water repellent coating treatment, so it has high water repellency. Furthermore, although the nozzle vane is not subjected to groove processing but is subjected to a water repellent coating treatment, it has water repellency while suppressing a decrease in performance and an increase in manufacturing cost. For this reason, the droplets in the nozzle flow path can be guided to the downstream side of the nozzle flow path, and icing on the nozzle flow path can be suppressed.

[0101]

[12] The operation method of the cooling device according to the present disclosure is An operation method of a cooling device for cooling a cooling chamber of a refrigerated container, the operation method of a cooling device including a turbine that expands the air sucked from the cooling chamber, is When the cooling device is started, the turbine is operated at a first rotational speed until the inlet temperature of the turbine drops below a preset inlet side specified temperature, and when the inlet temperature of the turbine is less than the inlet side specified temperature, the turbine is operated at a second rotational speed greater than the first rotational speed (step SA).

[0102] According to the method described in the above

[12] , the same effect as that of the above [1] is obtained.

[0103]

[13] The operation method of the cooling device according to the present disclosure is A method for operating a cooling device for cooling a cooling chamber of a refrigerated container, the method for operating a cooling device comprising a turbine that expands air sucked from the cooling chamber, When the cooling device is started, the turbine is operated at a first rotational speed until the outlet temperature of the turbine drops below a preset outlet-side specified temperature, and when the outlet temperature of the turbine is less than the outlet-side specified temperature, the turbine is operated at a second rotational speed greater than the first rotational speed, comprising step (SB).

[0104] According to the method described in

[13] above, the same effect as in [2] above is achieved.

[0105]

[14] The method for operating a cooling device according to the present disclosure is A method for operating a cooling device for cooling a cooling chamber of a refrigerated container, the method for operating a cooling device comprising a turbine that expands air sucked from the cooling chamber, When the cooling device is started, the turbine is operated at a first rotational speed until the outlet temperature of the turbine drops below a preset outlet-side specified temperature, and when the outlet temperature of the turbine is less than the outlet-side specified temperature, the turbine is operated at a second rotational speed greater than the first rotational speed. When the inlet temperature of the turbine drops below a preset inlet-side specified temperature, the turbine is operated at the second rotational speed, and when the inlet temperature of the turbine is less than the inlet-side specified temperature, the turbine is operated at a third rotational speed greater than the second rotational speed, comprising step (SC).

[0106] According to the method described in

[14] above, the same effect as in [3] above is achieved.

Explanation of reference numerals

[0107] 1 Cooling device 1A Cooling device (first embodiment) 1B Cooling device (second embodiment) 1C Cooling device (third embodiment) 2 Turbine 4 Control device 6 Air line 8 Heat exchanger 10 Compressor 12 Air cooler 14 Motor 15a Drive shaft 15b Drive shaft 16 Inlet temperature sensor 17 Outlet temperature sensor 20A Start-up operation unit (First embodiment) 20B Start-up operation unit (Second embodiment) 20C Start-up operation unit (Third embodiment) 21 Casing 22 Turbine rotor 23 Scroll flow path 24 Scroll flow path forming part 25 Nozzle flow path 26 Nozzle flow path forming part 30 Scroll flow path surface 32 Nozzle flow path surface 35 Moving blade 36 Scroll flow path groove 38 Nozzle flow path groove 40 Nozzle vane 42 Surface of nozzle vane 45 Discharge flow path 44 Discharge flow path forming part 46 Outlet 100 Refrigerated container 101 Cooling chamber 102 Main body part 200 Object 201 Surface of object 202 Droplet 203 Surface of droplet A1 Cooling air A2 Suction air D1 Axial direction D2 Radial direction D3 Circumferential direction Da Flow direction of suction air (scroll flow path) Db Flow direction of suction air (nozzle flow path) L Tangent line M Water-repellent layer O Axis P1 Point PA Instruction (First Embodiment) PB Instruction (Second Embodiment) PC Instruction (Third Embodiment) T1 Inlet Temperature T2 Outlet Temperature TA Specified Temperature on the Inlet Side TB Specified Temperature on the Outlet Side W1 Width of Scroll Flow Path Groove W2 Width of Nozzle Flow Path Groove X1 First Rotation Speed (Low Speed) X2 Second Rotation Speed (Medium Speed) X3 Third Rotation Speed (High Speed) SA First Start - up Operation Step SA1 Low - speed Operation Step SA2 Inlet Temperature Judgment Step SA3 High - speed Operation Step SB Second Start - up Operation Step SB1 Low - speed Operation Step SB2 Outlet Temperature Judgment Step SB3 High - speed Operation Step SC Third Start - up Operation Step SC1 Low - speed Operation Step SC2 Outlet Temperature Judgment Step SC3 Medium - speed Operation Step SC4 Inlet Temperature Judgment Step SC5 High - speed Operation Step

Claims

1. A cooling device for cooling a cooling chamber of a refrigerated container, comprising: a turbine that expands air sucked from the cooling chamber; a control device that controls the operation of the turbine, wherein the control device when the cooling device is started, operates the turbine at a first rotational speed until the inlet temperature of the turbine drops below a preset inlet-side specified temperature, and when the inlet temperature of the turbine is below the inlet-side specified temperature, operates the turbine at a second rotational speed greater than the first rotational speed, and includes a start-up operation unit for operating the turbine at the second rotational speed until the inlet temperature of the turbine drops below a preset inlet-side specified temperature, and when the inlet temperature of the turbine is below the inlet-side specified temperature, operates the turbine at a third rotational speed greater than the second rotational speed; Cooling device.

2. A cooling device for cooling a cooling chamber of a refrigerated container, comprising: a turbine that expands air sucked from the cooling chamber; a control device that controls the operation of the turbine, wherein the control device when the cooling device is started, operates the turbine at a first rotational speed until the outlet temperature of the turbine drops below a preset outlet-side specified temperature, and when the outlet temperature of the turbine is below the outlet-side specified temperature, operates the turbine at a second rotational speed greater than the first rotational speed, and includes a start-up operation unit for operating the turbine at the second rotational speed until the outlet temperature of the turbine drops below a preset outlet-side specified temperature, and when the outlet temperature of the turbine is below the outlet-side specified temperature, operates the turbine at a third rotational speed greater than the second rotational speed; Cooling device.

3. A cooling device for cooling a cooling chamber of a refrigerated container, comprising: a turbine that expands air sucked from the cooling chamber; a control device that controls the operation of the turbine, wherein the control device when the cooling device is started, operates the turbine at a first rotational speed until the outlet temperature of the turbine drops below a preset outlet-side specified temperature, and when the outlet temperature of the turbine is below the outlet-side specified temperature, operates the turbine at a second rotational speed greater than the first rotational speed, and when the inlet temperature of the turbine drops below a preset inlet-side specified temperature, operates the turbine at the second rotational speed until the inlet temperature of the turbine drops below a preset inlet-side specified temperature, and when the inlet temperature of the turbine is below the inlet-side specified temperature, operates the turbine at a third rotational speed greater than the second rotational speed, and includes a start-up operation unit for operating the turbine at the third rotational speed; Cooling device.

4. The turbine includes a turbine rotor; a scroll flow path forming portion that forms a scroll flow path on the outer peripheral side of the turbine rotor; a nozzle flow path forming portion that forms a nozzle flow path for guiding the air from the scroll flow path to the turbine rotor, wherein each of the scroll flow path forming portion and the nozzle flow path forming portion has water repellency; The cooling device according to any one of Claims 1 to 3.

5. Each of the scroll flow path forming portion and the nozzle flow path forming portion is made of an aluminum alloy. The cooling device according to claim 4.

6. The scroll flow path forming portion is subjected to a water-repellent coating treatment on the surface facing the scroll flow path. The nozzle flow path forming portion is subjected to a water-repellent coating treatment on the surface facing the nozzle flow path. The cooling device according to claim 4.

7. The scroll flow path forming portion has scroll flow path grooves formed on the surface facing the scroll flow path and extending along the flow direction of the air flowing through the scroll flow path. The scroll flow path grooves have a width of 0.01 mm or more and 0.5 mm or less. The cooling device according to claim 4.

8. The nozzle flow path forming portion has nozzle flow path grooves formed on the surface facing the nozzle flow path and extending along the flow direction of the air flowing through the nozzle flow path. The nozzle flow path grooves have a width of 0.01 mm or more and 0.5 mm or less. The cooling device according to claim 4.

9. The turbine further includes a plurality of nozzle vanes arranged at intervals in the circumferential direction of the turbine rotor in the nozzle flow path. The nozzle vanes are subjected to a water-repellent coating treatment on the surface facing the nozzle flow path and are not subjected to groove machining for forming grooves on the surface facing the nozzle flow path. The cooling device according to claim 4.

10. The turbine rotor includes a plurality of moving blades. The number of the nozzle vanes is smaller than that of the plurality of moving blades. The cooling device according to claim 9.

11. The turbine a turbine rotor, a scroll flow path forming portion that forms a scroll flow path on the outer peripheral side of the turbine rotor, a nozzle flow path forming portion that forms a nozzle flow path for guiding the air from the scroll flow path to the turbine rotor, and a plurality of nozzle vanes arranged at intervals in the circumferential direction of the turbine rotor in the nozzle flow path. The nozzle flow path forming portion is made of an aluminum alloy. The nozzle flow path forming portion has nozzle flow path grooves with a width of 0.01 mm or more and 0.5 mm or less formed on the surface facing the nozzle flow path and extending along the flow direction of the air flowing through the nozzle flow path, and the surface facing the nozzle flow path is subjected to a water-repellent coating treatment. The nozzle vane is subjected to a water-repellent coating treatment on the surface facing the nozzle flow path, and is not subjected to groove processing for forming grooves on the surface facing the nozzle flow path. The cooling device according to any one of claims 1 to 3.

12. A method for operating a cooling device for cooling a cooling chamber of a refrigerated container, the method for operating a cooling device including a turbine that expands air sucked from the cooling chamber, When the cooling device starts up, the turbine is operated at a first rotational speed until the inlet temperature of the turbine drops below a preset inlet-side specified temperature, and when the inlet temperature of the turbine is less than the inlet-side specified temperature, the turbine is operated at a second rotational speed greater than the first rotational speed. A method for operating a cooling device.

13. A method for operating a cooling device for cooling a cooling chamber of a refrigerated container, the method for operating a cooling device including a turbine that expands air sucked from the cooling chamber, When the cooling device starts up, the turbine is operated at a first rotational speed until the outlet temperature of the turbine drops below a preset outlet-side specified temperature, and when the outlet temperature of the turbine is less than the outlet-side specified temperature, the turbine is operated at a second rotational speed greater than the first rotational speed. A method for operating a cooling device.

14. A method for operating a cooling device for cooling a cooling chamber of a refrigerated container, the method for operating a cooling device including a turbine that expands air sucked from the cooling chamber, When the cooling device starts up, the turbine is operated at a first rotational speed until the outlet temperature of the turbine drops below a preset outlet-side specified temperature, and when the outlet temperature of the turbine is less than the outlet-side specified temperature, the turbine is operated at a second rotational speed greater than the first rotational speed. When the inlet temperature of the turbine drops below a preset inlet-side specified temperature, the turbine is operated at the second rotational speed, and when the inlet temperature of the turbine is less than the inlet-side specified temperature, the turbine is operated at a third rotational speed greater than the second rotational speed. A method for operating a cooling device.

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