Cooling apparatus

Abstract

A cooling apparatus comprises: a housing (11) of a spacecraft; and a sealed container (21) that is provided inside the housing (11) and is filled with a refrigerant liquid in which electronic equipment (22) is immersed. The electronic equipment (22) is in contact with a bottom surface (21a) of the sealed container (21). A lower surface (21b) of the sealed container (21), which is positioned on the opposite side from the bottom surface (21a) that is contact with the electronic equipment (22), is in contact with a bottom surface (11a) of the housing (11).

Description

Cooling device

[0001] The present disclosure relates to a cooling device.

[0002] Various electronic devices are mounted on spacecraft operating in space. In a spacecraft, when an electronic device generates heat, heat control may be required to discharge the heat generated from the electronic device outside the spacecraft.

[0003] Therefore, Patent Document 1 discloses a liquid immersion type cooling device (hereinafter simply referred to as a cooling device) as one of the heat control methods in a spacecraft. The cooling device disclosed in Patent Document 1 cools an electronic device, which is a heat source, by immersing it in a refrigerant liquid in a sealed container.

[0004] Japanese Patent Application Laid-Open No. 2023-124520

[0005] Here, the cooling device disclosed in Patent Document 1 further has a support mechanism and a forced liquid flow generator. The support mechanism supports the electronic device and the forced liquid flow generator inside the sealed container. For this reason, the electronic device is fixed at a substantially central position inside the sealed container. Further, the forced liquid flow generator is fixed at a position facing the main surface of the electronic device. The forced liquid flow generator forces the refrigerant liquid to flow inside the sealed container, thereby flowing the refrigerant liquid on the electronic device toward the inner wall of the sealed container. Therefore, the cooling device disclosed in Patent Document 1 cools the electronic device by driving the forced liquid flow generator.

[0006] As described above, the cooling device disclosed in Patent Document 1 cools the electronic device by forcibly circulating the refrigerant liquid inside the sealed container. For this reason, the cooling device disclosed in Patent Document 1 has a problem that its structure becomes complicated and the manufacturing process becomes complicated because it includes a forced liquid flow generator.

[0007] The present disclosure has been made to solve the above problems, and an object thereof is to provide a cooling device that can cool an electronic device without generating a forced flow of a refrigerant liquid.

[0008] The cooling device according to this disclosure comprises a spacecraft housing and a sealed container provided inside the housing, which is filled with a coolant liquid in which electronic equipment is immersed. The electronic equipment is in contact with the inner wall surface of the sealed container, and the outer wall surface of the sealed container located on the opposite side of the inner wall surface in contact with the electronic equipment is in contact with the inner wall surface of the housing.

[0009] According to this disclosure, electronic equipment can be cooled without generating a forced flow of refrigerant liquid. Therefore, this disclosure does not require a forced liquid flow generator, resulting in a simpler configuration and easier manufacturing process.

[0010] This is a schematic diagram of a spacecraft to which the cooling device according to Embodiment 1 is applied. This is a block diagram showing the configuration of the cooling control device according to Embodiment 1. This is a flowchart showing the operation of the cooling control device according to Embodiment 1. Figures 4A and 4B show an example of the hardware configuration of the cooling control device according to Embodiment 1. This is a schematic diagram of a spacecraft to which the cooling device according to Embodiment 2 is applied. This is a block diagram showing the configuration of the cooling control device according to Embodiment 3. This is a flowchart showing the operation of the cooling control device according to Embodiment 3.

[0011] To provide a more detailed explanation of this disclosure, the forms for implementing this disclosure will be described below with reference to the attached drawings.

[0012] Embodiment 1. The cooling device according to Embodiment 1 will be described with reference to Figures 1 to 4.

[0013] First, the configuration of a spacecraft to which the cooling system according to Embodiment 1 is applied will be explained using Figure 1. Figure 1 is a schematic diagram of the configuration of a spacecraft to which the cooling system according to Embodiment 1 is applied.

[0014] The spacecraft according to Embodiment 1 shown in Figure 1 is operated in outer space. The spacecraft according to Embodiment 1 orbits the Earth 61, for example, and during its orbit, a portion of it is illuminated by light from the sun 62. The spacecraft according to Embodiment 1 is, for example, an artificial satellite or a probe. Furthermore, the spacecraft according to Embodiment 1 is equipped with a liquid immersion type cooling system. Details of this cooling system according to Embodiment 1 will be described later.

[0015] As shown in Figure 1, the spacecraft according to Embodiment 1 has a housing 11. The housing 11 is, for example, a hollow cube or rectangular parallelepiped. The housing 11 is made of a metallic material such as aluminum or tungsten alloy in order to protect or shield the electronic equipment 22, which will be described later, from cosmic radiation.

[0016] The housing 11 houses a sealed container 21, electronic equipment 22, cooling equipment 31, a temperature sensor 32, an attitude sensor 33, an attitude control device 34, and a cooling control device 40A. The housing 11, sealed container 21, electronic equipment 22, cooling equipment 31, temperature sensor 32, attitude sensor 33, attitude control device 34, and cooling control device 40A constitute the cooling system according to Embodiment 1.

[0017] The sealed container 21, like the housing 11, is, for example, a cube or rectangular parallelepiped and is made of a metallic material such as aluminum or a tungsten alloy. The sealed container 21 is housed and held in the lowest part of the housing 11. Furthermore, the inside of the sealed container 21 is filled with a refrigerant liquid and sealed.

[0018] Electronic device 22 is a heat source in the spacecraft. Electronic device 22 is immersed in a coolant liquid inside a sealed container 21. Electronic device 22 is housed in the lowest part of the sealed container 21, and its sides are covered with the coolant liquid. Electronic device 22 is, for example, an optical device such as a semiconductor or an optical fiber module having a small diode. In such a case, electronic device 22 becomes an electronic device with a high heat density.

[0019] Here, the housing 11 has an inner wall surface, which is a bottom surface 11a, and an outer wall surface, which is a bottom surface 11b. The bottom surface 11a and the bottom surface 11b are surfaces located on opposite sides of each other in the thickness direction of the housing 11. Similarly, the sealed container 21 has an inner wall surface, which is a bottom surface 21a, and an outer wall surface, which is a bottom surface 21b. The bottom surface 21a and the bottom surface 21b are surfaces located on opposite sides of each other in the thickness direction of the sealed container 21. Furthermore, the electronic device 22 has an outer wall surface, which is a bottom surface 22a.

[0020] The lower surface 22a of the electronic device 22 is in contact with the bottom surface 21a of the sealed container 21. That is, the electronic device 22 is submerged in the refrigerant liquid until its lower surface 22a contacts the bottom surface 21a of the sealed container 21. The lower surface 21b of the sealed container 21 is in contact with the bottom surface 11a of the housing 11.

[0021] Therefore, the lower surface 22a of the electronic device 22 is thermally connected to the lower surface 11b of the housing 11 via the sealed container 21. In other words, the path from the lower surface 22a to the bottom surface 21a, the lower surface 21b, and the path from the bottom surface 11a to the lower surface 11b is a heat conduction path for the heat emitted from the electronic device 22. At this time, the lower surface 11b of the housing 11 becomes a heat dissipation surface for releasing that heat into outer space.

[0022] Therefore, when the electronic device 22 is driven and generates heat, the refrigerant liquid filling the sealed container 21 absorbs the heat emitted from the electronic device 22. As a result, the electronic device 22 is cooled. Furthermore, the heat emitted from the electronic device 22 is transferred sequentially to the bottom surface 22a of the electronic device 22, the bottom surfaces 21a and 21b of the sealed container 21, and the bottom surfaces 11a and 11b of the housing 11, and is released into space from the bottom surface 11b, which acts as a heat dissipation surface. As a result, the electronic device 22 is cooled.

[0023] As described above, the cooling device according to Embodiment 1 can shorten the heat conduction path by overlapping the electronic device 22, the bottom wall consisting of the bottom surface 21a and the lower surface 21b of the sealed container 21, and the bottom wall consisting of the bottom surface 11a and the lower surface 11b of the housing 11. Nothing such as a refrigerant liquid is interposed between them. In this case, the cooling device according to Embodiment 1 can transfer the heat emitted from the electronic device 22 to the housing 11, which has the largest heat capacity in the spacecraft or cooling device. For this reason, the cooling device according to Embodiment 1 can efficiently release the heat emitted from the electronic device 22 from the housing 11.

[0024] In addition, in the cooling device according to Embodiment 1, when the electronic equipment 22, the sealed container 21, and the housing 11 are stacked on top of each other, the side walls of the electronic equipment 22 and the sealed container 21 may be stacked on top of the side walls of the housing 11.

[0025] The cooling device 31 is installed between the housing 11 and the sealed container 21. The cooling device 31 may be directly connected to the housing 11 and the sealed container 21, or it may be connected indirectly. The cooling device 31 cools the electronic device 22 by transferring the heat emitted from the electronic device 22 from the sealed container 21 to the housing 11. Such a cooling device 31 is controlled by a cooling control device 40A, which will be described later. The cooling device 31 is, for example, an active cooling device such as a Peltier element or a heat pipe.

[0026] Specifically, the housing 11 has an inner surface 11c, which is an inner wall surface, and an outer surface 11d, which is an outer wall surface. The inner surface 11c and the outer surface 11d are surfaces located on opposite sides of each other in the thickness direction of the housing 11. The sealed container 21 has an inner surface 21c, which is an inner wall surface, and an outer surface 21d, which is an outer wall surface. The inner surface 21c and the outer surface 21d are surfaces located on opposite sides of each other in the thickness direction of the sealed container 21. The electronic device 22 has a side surface 22b, which is an outer wall surface.

[0027] The side surface 22b of the electronic device 22 is not in contact with the inner surface 21c of the sealed container 21. However, the side surface 22b of the electronic device 22 may be in contact with the inner surface 21c of the sealed container 21. The cooling device 31 is provided between the inner surface 11c of the housing 11 and the outer surface 21d of the sealed container 21. Therefore, the outer surface 21d of the sealed container 21 is thermally connected to the inner surface 11c of the housing 11 via the cooling device 31. In other words, the path from the inner surface 21c to the outer surface 21d, the cooling device 31, and then to the outer surface 11d via the inner surface 11c is a heat conduction path for the heat emitted from the electronic device 22. At this time, the outer surface 11d of the housing 11 becomes a heat dissipation surface for releasing that heat into outer space.

[0028] Therefore, the heat emitted from the electronic device 22 is transferred to the coolant liquid surrounding the electronic device 22. Then, the heat from the coolant liquid is transferred sequentially to the inner surface 21c and outer surface 21d of the sealed container 21, the cooling device 31, and the inner surface 11c and outer surface 11d of the housing 11, and is released into space from the outer surface 11d, which acts as a heat dissipation surface. As a result, the electronic device 22 is cooled.

[0029] Furthermore, when the side surface 22b of the electronic device 22 is in contact with the inner surface 21c of the sealed container 21, the heat emitted from the electronic device 22 is transferred sequentially from the side surface 22b of the electronic device 22, to the inner surface 21c and outer surface 21d of the sealed container 21, to the cooling device 31, and to the inner surface 11c and outer surface 11d of the housing 11, and is released into space from the outer surface 11d, which acts as a heat dissipation surface. As a result, the electronic device 22 is cooled.

[0030] Thus, the cooling device according to Embodiment 1 shortens the heat conduction path by overlapping the side wall consisting of the inner surface 21c and outer surface 21d of the sealed container 21, the cooling device 31, and the side wall consisting of the inner surface 11c and outer surface 11d of the housing 11. Nothing such as a refrigerant liquid is interposed between them. In this case, the cooling device according to Embodiment 1 can transfer the heat emitted from the electronic equipment 22 to the housing 11, which has the largest heat capacity among the spacecraft or cooling device. For this reason, the cooling device according to Embodiment 1 can efficiently release the heat emitted from the electronic equipment 22 from the housing 11.

[0031] The temperature sensor 32 detects the temperature of the electronic device 22. The temperature sensor 32 transmits temperature information indicating the detected temperature of the electronic device 22 to the cooling control device 40A. The temperature sensor 32 is, for example, an infrared sensor, a thermocouple, or a thermistor. The temperature sensor 32 may also be installed inside the sealed container 21.

[0032] Here, when the temperature sensor 32 detects the temperature of the electronic device 22, the temperature sensor 32 may detect the temperature directly or indirectly. Furthermore, when the temperature sensor 32 directly detects the temperature of the electronic device 22, the temperature sensor 32 may be in contact with or not in contact with the electronic device 22. Also, when the temperature sensor 32 indirectly detects the temperature of the electronic device 22, the temperature sensor 32 may detect the temperature of the refrigerant liquid or the temperature of the sealed container 21 and estimate the temperature of the electronic device 22 from the detected temperature.

[0033] The attitude sensor 33 detects the attitude of the spacecraft's housing 11 relative to the Earth 61 or the Sun 62 (including the orientation of the housing 11). The attitude sensor 33 transmits the detected attitude information of the spacecraft to the cooling control device 40A. The attitude sensor 33 can be, for example, a solar sensor, a star tracker, a gyroscope, an Earth sensor, a magnetic sensor, etc.

[0034] The attitude control device 34 controls the attitude of the spacecraft based on the detection results of the attitude sensor 33. The attitude control device 34 is controlled by the cooling control device 40A. The attitude control device 34 is, for example, a reaction wheel, gimbal, or gyroscope.

[0035] Next, the configuration and operation of the cooling control device 40A according to Embodiment 1 will be explained with reference to Figures 2 and 3.

[0036] Figure 2 is a block diagram showing the configuration of the cooling control device 40A according to Embodiment 1.

[0037] As shown in Figure 2, the cooling control device 40A includes a temperature information acquisition unit 41, a temperature determination unit 42, a posture change determination unit 43, a cooling equipment control unit 44, a posture information acquisition unit 45, and a posture control unit 46.

[0038] The temperature information acquisition unit 41 acquires temperature information transmitted from the temperature sensor 32. The temperature information acquisition unit 41 transmits the acquired temperature information to the temperature determination unit 42.

[0039] The temperature determination unit 42 acquires temperature information transmitted from the temperature information acquisition unit 41. The temperature determination unit 42 determines whether the temperature of the electronic device 22 exceeds a threshold. If the temperature of the electronic device 22 exceeds the threshold, the temperature determination unit 42 transmits a command signal to the attitude change determination unit 43. The threshold is a temperature below the boiling point of the refrigerant liquid filling the sealed container 21.

[0040] The posture change determination unit 43 receives the command signal transmitted from the temperature determination unit 42. When the temperature determination unit 42 determines that the temperature of the electronic device 22 has exceeded the threshold value, the posture change determination unit 43 determines whether the attitude of the spacecraft can be changed. Here, when the posture change determination unit 43 determines that the attitude of the spacecraft cannot be changed, it transmits the command signal to the cooling device control unit 44. Further, when the posture change determination unit 43 determines that the attitude of the spacecraft can be changed, it transmits the command signal to the attitude control unit 46.

[0041] The reason why the cooling control device 40A requires the posture change determination unit 43, that is, the reason why the posture change determination unit 43 determines whether the attitude of the spacecraft can be changed when the temperature determination unit 42 determines that the temperature of the electronic device 22 has exceeded the threshold value, will be described.

[0042] The attitude of the spacecraft is not always in a state where it can be changed. Therefore, the cooling control device 40 according to the first embodiment requires the posture change determination unit 43 in order to change the cooling approach for the electronic device 22 depending on whether the attitude of the spacecraft can be changed, which is an important factor in the cooling operation.

[0043] The case where the attitude of the spacecraft can be changed is, for example, when the attitude control of the spacecraft is not required. Specifically, it is the case where the spacecraft does not need to maintain a specific attitude such as scientific observation or communication link establishment. Also, it is the case where the attitude control device 34 such as a reaction wheel or gyro operates normally. Further, it is the case where the attitude sensor 33 such as a star tracker or gyroscope, which is necessary for determining the attitude of the spacecraft, functions normally and can accurately obtain the attitude information of the spacecraft.

[0044] On the other hand, the case where the attitude of the spacecraft cannot be changed is, for example, when the attitude control of the spacecraft is required. Specifically, it is the case where some mission is being executed and earth observation, communication, or data transfer with the ground is being performed. Also, it is the case where the attitude sensor 33 or the attitude control device 34 malfunctions due to some reason, and the attitude information of the spacecraft cannot be appropriately obtained, and the spacecraft cannot safely change its attitude.

[0045] When the cooling device control unit 44 receives the command signal transmitted from the temperature determination unit 42, it controls the cooling device 31. That is, the cooling device control unit 44 drives the cooling device 31. Therefore, since the temperature of the refrigerant liquid decreases due to the driving of the cooling device 31, the electronic device 22 is cooled by contact with the refrigerant liquid.

[0046] The attitude information acquisition unit 45 acquires the attitude information transmitted from the attitude sensor 33. The attitude information acquisition unit 45 transmits the acquired attitude information to the attitude control unit 46.

[0047] The attitude control unit 46 acquires the command signal transmitted from the attitude change determination unit 43 and the attitude information transmitted from the attitude information acquisition unit 45. Then, the attitude control unit 46 controls the attitude control device 34 by transmitting a command signal indicating that the current attitude of the spacecraft is to be changed to a predetermined attitude to the attitude control device 34. In contrast, the attitude control device 34 drives so that the attitude of the spacecraft becomes a predetermined attitude.

[0048] Here, the predetermined attitude is the attitude of the spacecraft such that the lower surface 11b and the outer surface 11d, which are the heat dissipation surfaces of the housing 11, face the deep space in a direction where the Earth 61 and the Sun 62 do not exist. Therefore, the cooling control device 40A can suppress the direct sunlight from the Sun 62 and the reflected sunlight from the Earth 61 from irradiating the lower surface 11b and the outer surface 11d of the housing 11. As a result, the cooling control device 40A can improve the heat dissipation effect from the lower surface 11b and the outer surface 11d of the housing 11.

[0049] FIG. 3 is a flowchart showing the operation of the cooling control device 40A according to the first embodiment.

[0050] As shown in FIG. 3, first, in step ST11, the electronic device 22 is driven. At this time, the electronic device 22 is driven while being cooled by the refrigerant liquid.

[0051] In step ST12, the temperature information acquisition unit 41 acquires the temperature information transmitted from the temperature sensor 32.

[0052] In step ST13, the temperature determination unit 42 determines whether the temperature of the electronic device 22 has exceeded a threshold. If the temperature determination unit 42 determines that the temperature of the electronic device 22 has exceeded the threshold (YES), the operation of the cooling control device 40A proceeds to step ST14. On the other hand, if the temperature determination unit 42 determines that the temperature of the electronic device 22 has not exceeded the threshold (NO), the operation of the cooling control device 40A returns to step ST12.

[0053] In step ST14, the attitude change determination unit 43 determines whether or not the attitude of the spacecraft can be changed. If the attitude change determination unit 43 determines that the attitude of the spacecraft cannot be changed (NO), the operation of the cooling control device 40A proceeds to step ST15. On the other hand, if the attitude change determination unit 43 determines that the attitude of the spacecraft can be changed (YES), the operation of the cooling control device 40A proceeds to step ST18.

[0054] In step ST15, the cooling equipment control unit 44 drives the cooling equipment 31. As a result, the heat emitted from the electronic equipment 22 is transferred to the coolant liquid, and then sequentially to the side wall of the sealed container 21, the cooling equipment 31, and the side wall of the housing 11. Consequently, the heat emitted from the electronic equipment 22 is released into space from the outer surface 11d of the housing 11. Thus, the electronic equipment 22 is cooled by radiation.

[0055] In step ST16, the temperature determination unit 42 determines whether the temperature of the electronic device 22 is below a threshold. If the temperature determination unit 42 determines that the temperature of the electronic device 22 is below the threshold (YES), the operation of the cooling control device 40A proceeds to step ST17. On the other hand, if the temperature determination unit 42 determines that the temperature of the electronic device 22 is not below the threshold (NO), the operation of the cooling control device 40A returns to step ST14.

[0056] In step ST17, the cooling equipment control unit 44 stops the operation of the cooling equipment 31. As a result, the electronic equipment 22 is operated while being cooled only by the refrigerant liquid. Then, the operation of the cooling control device 40A ends.

[0057] Furthermore, in step ST18, the posture information acquisition unit 45 acquires posture information transmitted from the posture sensor 33.

[0058] In step ST19, the attitude control unit 46 drives the attitude control device 34. As a result, the attitude control device 34 is driven so that the attitude of the spacecraft becomes a predetermined attitude. Consequently, the bottom surface 11b and the outer surface 11d of the housing 11, which are heat dissipation surfaces, face deep space, which is the direction in which the Earth 61 and the Sun 62 do not exist. Therefore, heat dissipation from the bottom surface 11b and the outer surface 11d of the housing 11 is promoted.

[0059] In step ST20, the temperature determination unit 42 determines whether the temperature of the electronic device 22 is below a threshold. If the temperature determination unit 42 determines that the temperature of the electronic device 22 is below the threshold (YES), the operation of the cooling control device 40A ends. On the other hand, if the temperature determination unit 42 determines that the temperature of the electronic device 22 is not below the threshold (NO), the operation of the cooling control device 40A returns to step ST14.

[0060] Next, an example of the hardware configuration of the cooling control device 40A according to Embodiment 1 will be described with reference to Figure 4. Figures 4A and 4B are diagrams showing an example of the hardware configuration of the cooling control device 40A according to Embodiment 1.

[0061] As shown in Figure 4A, the cooling control device 40A is composed of a computer, which has a processor 51 and a memory 52. ​​The memory 52 stores programs that cause the computer to function as a temperature information acquisition unit 41, a temperature determination unit 42, a posture change determination unit 43, a cooling equipment control unit 44, a posture information acquisition unit 45, and a posture control unit 46. The processor 51 reads and executes the programs stored in the memory 52, thereby realizing the functions of the temperature information acquisition unit 41, the temperature determination unit 42, the posture change determination unit 43, the cooling equipment control unit 44, the posture information acquisition unit 45, and the posture control unit 46.

[0062] Alternatively, as shown in Figure 4B, the cooling control device 40A may have a processing circuit 53. In this case, the processing circuit 53 may be implemented by a temperature information acquisition unit 41, a temperature determination unit 42, a posture change determination unit 43, a cooling equipment control unit 44, a posture information acquisition unit 45, and a posture control unit 46.

[0063] Alternatively, the cooling control device 40A may have a processor 51, a memory 52, and a processing circuit 53 (not shown). In this case, some of the functions of the temperature information acquisition unit 41, temperature determination unit 42, attitude change determination unit 43, cooling equipment control unit 44, attitude information acquisition unit 45, and attitude control unit 46 may be implemented by the processor 51 and memory 52, and the remaining functions may be implemented by the processing circuit 53.

[0064] The processor 51 uses, for example, at least one of the following: a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), a microprocessor, a microcontroller, or a DSP (Digital Signal Processor).

[0065] The memory 52 uses, for example, at least one of semiconductor memory or magnetic disk. More specifically, the memory 52 uses at least one of RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), SSD (Solid State Drive), or HDD (Hard Disk Drive).

[0066] The processing circuit 53 uses, for example, at least one of the following: ASIC (Application Specific Integrated Circuit), PLD (Programmable Logic Device), FPGA (Field-Programmable Gate Array), SoC (System-on-a-Chip), or System LSI (Large-Scale Integration).

[0067] As described above, the cooling device according to Embodiment 1 comprises a spacecraft housing 11 and a sealed container 21 provided inside the housing 11 and filled with a refrigerant liquid in which the electronic equipment 22 is immersed. The electronic equipment 22 is in contact with the bottom surface 21a of the sealed container 21, and the lower surface 21b of the sealed container 21, located on the opposite side of the bottom surface 21a in contact with the electronic equipment 22, is in contact with the bottom surface 11a of the housing 11. Therefore, the cooling device according to Embodiment 1 can cool the electronic equipment 22 without generating a forced flow of refrigerant liquid. As a result, the cooling device according to Embodiment 1 does not need to be equipped with a forced flow generator for generating a forced flow of refrigerant liquid, its configuration is simplified, and the manufacturing process can be made easier.

[0068] The cooling device according to Embodiment 1 includes a cooling device 31 provided between the inner surface 11c of the housing 11 and the outer surface 21d of the sealed container 21. Therefore, the cooling device according to Embodiment 1 can release the heat emitted from the electronic device 22 into outer space from the outer surface 11d of the housing 11.

[0069] In the cooling device according to Embodiment 1, the lower surface 21b located on the opposite side of the bottom surface 21a in which the electronic device 22 abuts the sealed container 21, and the outer surface 21d in which the cooling device 31 abuts the sealed container 21, are different surfaces. Therefore, the cooling device according to Embodiment 1 can release the heat emitted from the electronic device 22 using two heat conduction paths.

[0070] The cooling device according to Embodiment 1 includes a cooling control device 40A. The cooling control device 40A includes a temperature determination unit 42 that determines whether the temperature of the electronic equipment 22 exceeds a threshold, an attitude change determination unit 43 that determines whether the attitude of the spacecraft can be changed if the temperature of the electronic equipment 22 is determined to have exceeded the threshold, a cooling equipment control unit 44 that drives the cooling device 31 if the attitude change determination unit 43 determines that the attitude of the spacecraft cannot be changed, and an attitude control unit 46 that drives an attitude control device 34 capable of controlling the attitude of the spacecraft if the attitude change determination unit 43 determines that the attitude of the spacecraft can be changed.Therefore, the cooling device according to Embodiment 1 can cool the electronic equipment 22 without generating a forced flow of refrigerant liquid.

[0071] In the cooling device according to Embodiment 1, the cooling device control unit 44 drives the cooling device 31, and if the temperature determination unit 42 determines that the temperature of the electronic device 22 is below a threshold, it stops driving the cooling device 31. Therefore, the cooling device according to Embodiment 1 can save energy in the cooling device 31.

[0072] In the cooling device according to Embodiment 1, the attitude control unit 46 controls the attitude control device 34 so that the lower surface 11b of the housing 11 facing the electronic equipment 22, and the outer surface 11d of the housing 11 facing the cooling device, face directions where the Earth 61 and the Sun 62 do not exist. The cooling device according to Embodiment 1 can improve the heat dissipation effect from the lower surface 11b and the outer surface 11d of the housing 11.

[0073] Embodiment 2. The cooling device according to Embodiment 2 will be described with reference to Figure 5. Figure 5 is a schematic diagram of a spacecraft to which the cooling device according to Embodiment 2 is applied. Components having the same function as those described in the above-described embodiments are denoted by the same reference numerals, and their descriptions are omitted.

[0074] The cooling device according to Embodiment 2 shown in Figure 5 is modified by adding a bubble adhesion prevention member 23 to the configuration of the cooling device according to Embodiment 1 shown in Figure 1.

[0075] As shown in Figure 5, the bubble-preventing member 23 is provided on the surface of the electronic device 22. The bubble-preventing member 23 prevents bubbles from adhering to the surface of the electronic device 22. Specifically, the bubble-preventing member 23 is provided on the area of ​​the entire surface of the electronic device 22 that comes into contact with the refrigerant liquid.

[0076] The bubble-preventing member 23 is formed, for example, in the form of a sheet. In this case, the bubble-preventing member 23 is made of a highly hydrophilic material. Alternatively, the bubble-preventing member 23 may be a surface coating made of a highly hydrophilic material.

[0077] Thus, the cooling device according to Embodiment 2, by providing a bubble adhesion prevention member 23 on the surface of the electronic device 22, prevents bubbles from adhering to the surface of the electronic device 22, thereby allowing for greater contact with the refrigerant liquid. As a result, the cooling device according to Embodiment 2 can sufficiently cool the electronic device 22 with the refrigerant liquid even if bubbles accidentally enter the refrigerant liquid filling the sealed container 21.

[0078] As described above, the cooling device according to Embodiment 2 includes a bubble adhesion prevention member 23 provided on the surface of the electronic device 22. Therefore, even if bubbles accidentally enter the refrigerant liquid filling the sealed container 21, the cooling device according to Embodiment 2 can sufficiently cool the electronic device 22 with the refrigerant liquid.

[0079] Embodiment 3. The cooling device according to Embodiment 3 will be described with reference to Figures 6 and 7. Components having the same function as those described in the above-described embodiments are denoted by the same reference numerals, and their descriptions are omitted.

[0080] Figure 6 is a block diagram showing the configuration of the cooling control device 40C according to Embodiment 3. As shown in Figure 6, the cooling device according to Embodiment 3 is equipped with a cooling control device 40C instead of the cooling control device 40A of the cooling device according to Embodiment 1 shown in Figure 2. The cooling control device 40C according to Embodiment 3 has an electronic equipment control unit 47 compared to the configuration of the cooling control device 40A according to Embodiment 1.

[0081] When the electronic equipment control unit 47 receives a command signal transmitted from the temperature determination unit 42, it controls the electronic equipment 22. Specifically, if the temperature determination unit 42 determines that the temperature of the electronic equipment 22 exceeds a threshold, the electronic equipment control unit 47 stops the operation of the electronic equipment 22. After stopping the operation of the electronic equipment 22, the electronic equipment control unit 47 transmits a command signal to the attitude change determination unit 43.

[0082] The attitude change determination unit 43 receives a command signal transmitted from the electronic equipment control unit 47. The attitude change determination unit 43 determines whether the attitude of the spacecraft can be changed if the electronic equipment control unit 47 stops the operation of the electronic equipment 22. If the attitude change determination unit 43 determines that the attitude of the spacecraft cannot be changed, it transmits a command signal to the cooling equipment control unit 44. If the attitude change determination unit 43 determines that the attitude of the spacecraft can be changed, it transmits a command signal to the attitude control unit 46.

[0083] Figure 7 is a flowchart showing the operation of the cooling control device 40C according to Embodiment 3.

[0084] As shown in Figure 7, first, in step ST31, the electronic device 22 is driven. At this time, the electronic device 22 is driven while being cooled by the refrigerant liquid.

[0085] In step ST32, the temperature information acquisition unit 41 acquires the temperature information transmitted from the temperature sensor 32.

[0086] In step ST33, the temperature determination unit 42 determines whether the temperature of the electronic device 22 has exceeded a threshold. If the temperature determination unit 42 determines that the temperature of the electronic device 22 has exceeded the threshold (YES), the operation of the cooling control device 40C proceeds to step ST34. On the other hand, if the temperature determination unit 42 determines that the temperature of the electronic device 22 has not exceeded the threshold (NO), the operation of the cooling control device 40C returns to step ST32.

[0087] In step ST34, the electronic equipment control unit 47 stops the operation of the electronic equipment 22. By stopping the operation of the electronic equipment 22, which is a heat source, the conduction of heat emitted from the electronic equipment 22 is eliminated.

[0088] In step ST35, the attitude change determination unit 43 determines whether or not the attitude of the spacecraft can be changed. If the attitude change determination unit 43 determines that the attitude of the spacecraft cannot be changed (NO), the operation of the cooling control device 40C proceeds to step ST36. On the other hand, if the attitude change determination unit 43 determines that the attitude of the spacecraft can be changed (YES), the operation of the cooling control device 40C proceeds to step ST40.

[0089] In step ST36, the cooling equipment control unit 44 drives the cooling equipment 31. As a result, the heat emitted from the electronic equipment 22 is transferred to the coolant liquid, and then sequentially to the side wall of the sealed container 21, the cooling equipment 31, and the side wall of the housing 11. Consequently, the heat emitted from the electronic equipment 22 is released into space from the outer surface 11d of the housing 11. Thus, the electronic equipment 22 is cooled by radiation.

[0090] In step ST37, the temperature determination unit 42 determines whether the temperature of the electronic device 22 is below a threshold. If the temperature determination unit 42 determines that the temperature of the electronic device 22 is below the threshold (YES), the operation of the cooling control device 40C proceeds to step ST38. On the other hand, if the temperature determination unit 42 determines that the temperature of the electronic device 22 is not below the threshold (NO), the operation of the cooling control device 40C returns to step ST35.

[0091] In step ST38, the cooling equipment control unit 44 stops the operation of the cooling equipment 31.

[0092] In step ST39, the electronic equipment control unit 47 drives the electronic equipment 22. Therefore, the electronic equipment 22 is driven while being cooled only by the refrigerant liquid. Then, the operation of the cooling control device 40C ends.

[0093] Furthermore, in step ST40, the posture information acquisition unit 45 acquires posture information transmitted from the posture sensor 33.

[0094] In step ST41, the attitude control unit 46 drives the attitude control device 34. As a result, the attitude control device 34 is driven so that the attitude of the spacecraft becomes a predetermined attitude. Consequently, the bottom surface 11b and the outer surface 11d of the housing 11, which are heat dissipation surfaces, face deep space, which is the direction in which the Earth 61 and the Sun 62 do not exist. Therefore, heat dissipation from the bottom surface 11b and the outer surface 11d of the housing 11 is promoted.

[0095] In step ST42, the temperature determination unit 42 determines whether the temperature of the electronic device 22 is below a threshold. If the temperature determination unit 42 determines that the temperature of the electronic device 22 is below the threshold (YES), the operation of the cooling control device 40C ends. On the other hand, if the temperature determination unit 42 determines that the temperature of the electronic device 22 is not below the threshold (NO), the operation of the cooling control device 40C returns to step ST35.

[0096] As described above, the cooling device according to Embodiment 3 includes a cooling control device 40C. The cooling control device 40C includes a temperature determination unit 42 that determines whether the temperature of the electronic equipment 22 exceeds a threshold, an electronic equipment control unit 47 that stops the operation of the electronic equipment 22 if the temperature determination unit 42 determines that the temperature of the electronic equipment 22 has exceeded the threshold, an attitude change determination unit 43 that determines whether the attitude of the spacecraft can be changed if the operation of the electronic equipment 22 has been stopped by the electronic equipment control unit 47, a cooling equipment control unit 44 that drives the cooling equipment 31 if the attitude change determination unit 43 determines that the attitude of the spacecraft cannot be changed, and an attitude control unit 46 that drives an attitude control device 34 capable of controlling the attitude of the spacecraft if the attitude change determination unit 43 determines that the attitude of the spacecraft can be changed.Therefore, the cooling device according to Embodiment 3 can cool the electronic equipment 22 without generating a forced flow of refrigerant liquid.

[0097] Embodiment 4. The cooling device according to Embodiment 4 will be described.

[0098] In the fourth embodiment of the cooling device, the attitude control unit 46 controls the attitude control device 34 to change the current attitude of the spacecraft to a predetermined attitude. This control rotates the spacecraft's housing 11 at least once before changing the spacecraft's attitude to the predetermined attitude. As a result, convection occurs in the refrigerant liquid, which had an uneven temperature distribution within the sealed container 21. Consequently, heat in the refrigerant liquid becomes more easily diffused into the sealed container 21.

[0099] As described above, in the cooling device according to Embodiment 4, the attitude control unit 46 rotates the housing 11 by one or more rotations, and then controls the attitude control device 34 so that the lower surface 11b of the housing 11 facing the electronic equipment 22 and the outer surface 11d of the housing 11 facing the cooling device 31 face directions where the Earth 61 and the Sun 62 do not exist. Therefore, the cooling device according to Embodiment 4 can diffuse the heat in the refrigerant liquid into the sealed container 21 and improve the heat dissipation effect.

[0100] Embodiment 5. The cooling device according to Embodiment 5 will be described.

[0101] The cooling device according to Embodiment 5 has one temperature sensor 32. The temperature sensor 32 according to Embodiment 5 is capable of detecting the temperature of the entire electronic device 22, rather than detecting the temperature of only a part of the electronic device 22. In this case, the temperature sensor 32 is preferably an infrared sensor, for example. Therefore, since the cooling device according to Embodiment 5 can detect the overall temperature distribution of the electronic device 22, it can respond quickly even if the electronic device 22 generates heat at an abnormally high temperature locally.

[0102] As described above, the cooling device according to Embodiment 5 is provided inside the housing 11 and includes a temperature sensor 32 that detects the overall temperature of the electronic device 22. Therefore, the cooling device according to Embodiment 5 can respond quickly even if the electronic device 22 generates heat at an abnormally high temperature locally.

[0103] Embodiment 6. The cooling device according to Embodiment 6 will be described.

[0104] The cooling device according to Embodiment 6 has a plurality of temperature sensors 32. Each temperature sensor 32 according to Embodiment 5 is capable of detecting different points on the electronic device 22. In this case, if the temperature detected by at least one of the plurality of temperature sensors 32 exceeds a threshold, the temperature determination unit 42 transmits a command signal to the attitude change determination unit 43 or the electronic device control unit 47. Therefore, the cooling device according to Embodiment 6 can efficiently detect the temperature of the electronic device 22.

[0105] As described above, the cooling device according to Embodiment 6 is provided within the housing 11 and includes a plurality of temperature sensors 32 that detect different points in the electronic device 22. Therefore, the cooling device according to Embodiment 6 can efficiently detect the temperature of the electronic device 22.

[0106] Embodiment 7. The cooling device according to Embodiment 7 will be described.

[0107] The refrigerant liquid used in the cooling device according to Embodiment 7 is a mixture of two or more high-boiling-point insulated media. The high-boiling-point insulated media have a high boiling point, are insulated, and are chemically stable, meaning that they do not chemically react with each other when mixed. Examples of high-boiling-point insulated media include silicone oil and fluorocarbons. Therefore, the cooling device according to Embodiment 7 can improve heat transfer efficiency while utilizing the characteristics of each high-boiling-point insulated medium by using a refrigerant liquid that is a mixture of high-boiling-point insulated media of different types.

[0108] As described above, in the cooling device according to Embodiment 7, the refrigerant liquid is composed of multiple media of different types. Therefore, the cooling device according to Embodiment 7 can improve heat transfer efficiency while making use of the characteristics of each medium.

[0109] Within the scope of this disclosure, it is possible to freely combine the embodiments, modify any component in each embodiment, or omit any component in each embodiment.

[0110] The cooling device according to this disclosure can cool electronic equipment without generating a forced flow of refrigerant liquid by bringing the bottom surface of the sealed container, located on the opposite side of the bottom surface to which the electronic equipment is in contact, into contact with the bottom surface of the housing, and is therefore suitable for use in cooling devices.

[0111] 11 Housing, 11a Bottom, 11b Bottom, 11c Inner surface, 11d Outer surface, 21 Sealed container, 21a Bottom, 21b Bottom, 21c Inner surface, 21d Outer surface, 22 Electronic equipment, 22a Bottom, 22b Side, 23 Bubble adhesion prevention member, 31 Cooling equipment, 32 Temperature sensor, 33 Attitude sensor, 34 Attitude control device, 40A, 40C Cooling control device, 41 Temperature information acquisition unit, 42 Temperature determination unit, 43 Attitude change determination unit, 44 Cooling equipment control unit, 45 Attitude information acquisition unit, 46 Attitude control unit, 47 Electronic equipment control unit, 51 Processor, 52 Memory, 53 Processing circuit, 61 Earth, 62 Sun.

Claims

1. A cooling device comprising a spacecraft housing and a sealed container provided inside the housing and filled with a refrigerant liquid in which electronic equipment is immersed, wherein the electronic equipment is in contact with the inner wall surface of the sealed container, and the outer wall surface of the sealed container located on the opposite side of the inner wall surface in contact with the electronic equipment is in contact with the inner wall surface of the housing.

2. The cooling device according to claim 1, characterized in that it comprises a cooling device provided between the inner wall surface of the housing and the outer wall surface of the sealed container.

3. The cooling device according to claim 2, characterized in that the outer wall surface located on the opposite side of the inner wall surface in which the electronic device abuts the sealed container and the outer wall surface in which the cooling device abuts the sealed container are different surfaces from each other.

4. The cooling device according to any one of claims 1 to 3, characterized by comprising a bubble adhesion prevention member provided on the surface of the electronic device.

5. The cooling device according to claim 2 or 3, further comprising: a temperature determination unit that determines whether the temperature of the electronic device exceeds a threshold; an attitude change determination unit that determines whether the attitude of the spacecraft can be changed if the temperature of the electronic device has determined that the temperature of the electronic device has exceeded a threshold; a cooling device control unit that drives the cooling device if the attitude change determination unit has determined that the attitude of the spacecraft cannot be changed; and an attitude control unit that drives an attitude control device capable of controlling the attitude of the spacecraft if the attitude change determination unit has determined that the attitude of the spacecraft can be changed.

6. The cooling device according to claim 2 or 3, further comprising: a temperature determination unit that determines whether the temperature of the electronic device exceeds a threshold; an electronic device control unit that stops the operation of the electronic device if the temperature of the electronic device is determined to have exceeded a threshold; an attitude change determination unit that determines whether the attitude of the spacecraft can be changed if the operation of the electronic device is stopped by the electronic device control unit; a cooling device control unit that drives the cooling device if the attitude change determination unit determines that the attitude of the spacecraft cannot be changed; and an attitude control unit that drives an attitude control device capable of controlling the attitude of the spacecraft if the attitude change determination unit determines that the attitude of the spacecraft can be changed.

7. The cooling device according to claim 5 or 6, characterized in that, after driving the cooling device, the cooling device control unit stops driving the cooling device if the temperature determination unit determines that the temperature of the electronic device is below a threshold.

8. The cooling device according to any one of claims 5 to 7, characterized in that the attitude control unit controls the attitude control device such that the outer wall surface of the housing facing the electronic equipment and the outer wall surface of the housing facing the cooling equipment face directions in which the Earth and the Sun do not exist.

9. The cooling device according to claim 8, characterized in that the attitude control unit rotates the housing by one or more rotations and then controls the attitude control unit so that the outer wall surface of the housing facing the electronic equipment and the outer wall surface of the housing facing the cooling equipment face directions in which the Earth and the Sun do not exist.

10. The cooling device according to any one of claims 5 to 9, further comprising a temperature sensor provided within the housing for detecting the overall temperature of the electronic device.

11. The cooling device according to any one of claims 5 to 9, further comprising a plurality of temperature sensors provided within the housing, each detecting a different point in the electronic device.

12. The cooling device according to any one of claims 1 to 11, characterized in that the refrigerant liquid is composed of a plurality of media of different types.

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