Boiling cooling device and method for cooling a heating element

Abstract

To provide evaporative cooling device capable of suppressing deterioration of a cooling performance.SOLUTION: An evaporative cooling device 1 comprises: a heat reception part 10; a heat discharge part 20 having a heat discharge container 21 arranged so as to be inclined to a vertical line A; a first pipe part 31 having a first flow channel S1 that transports a gas coolant to the heat discharge part 20; and a second pipe part 32 having a second coolant channel S2 that transports the liquid phase coolant to the heat reception part 10. Each of a center line A1 of the first flow channel S1 and a center line A2 of the second flow channel S2 extends in a liner state. The first pipe part 31 includes: a first open part 301 opened toward the heat reception part 10; and a second open part 302 opened toward the heat discharge part 20. The second pipe part 32 includes: a third open part 303 opened toward the heat reception part 10; and a fourth open part 304 opened toward the heat discharge part 110. A center O1 of the first open part 301 is positioned to an upper direction from a center O3 of the third open part 303. The center O2 of the second open part 302 is positioned to an upper direction from a center O4 of the fourth open part 304.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a boiling cooling device and a method for cooling a heating element.

Background Art

[0002] There is known a boiling cooling device that cools a heating element by utilizing heat transport by latent heat accompanying boiling of a refrigerant.

[0003] The cooling device described in Patent Document 1 includes a heat receiving part, a heat radiating part, and two connecting parts that connect these. The heat receiving part receives heat from an object to be cooled and vaporizes a refrigerant by the heat. The heat radiating part condenses and liquefies the refrigerant. One of the two connecting parts is a vapor pipe that transports the refrigerant vaporized in the heat receiving part to the heat radiating part. The other is a liquid pipe that transports the refrigerant condensed and liquefied in the heat radiating part to the heat receiving part.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the heat radiating part, a liquid film is formed as the refrigerant condenses. When the heat radiating part of a conventional cooling device is used with an inclination with respect to the vertical line, the thickness of the liquid film becomes non-uniform compared to the case where the heat radiating part is arranged along the vertical line. For this reason, in the heat radiating part, a portion where the thickness of the liquid film is thick occurs compared to the case where the heat radiating part is used without being inclined. In this portion, as the thickness increases, the thermal resistance of the liquid film increases. As a result, the efficiency of condensation heat transfer decreases. Therefore, there is a problem that it becomes difficult for the liquid to circulate, and thus the cooling performance deteriorates.

Means for Solving the Problems

[0006] In order to solve the above problems, a boiling cooling device according to one aspect of the present invention includes a heat receiving portion that stores a refrigerant and receives heat from a heating element, and a heat radiating container that is disposed inclined with respect to a horizontal plane, and has a heat radiating portion that radiates heat from the heat receiving portion, a first pipe portion having a first flow path that transports a vapor-phase refrigerant generated by vaporizing the refrigerant in the heat receiving portion to the heat radiating portion, and a second pipe portion having a second flow path that transports a liquid-phase refrigerant generated by condensing the vapor-phase refrigerant in the heat radiating portion to the heat receiving portion. The center line of the first flow path and the center line of the second flow path each extend linearly. The first pipe portion has a first opening that opens toward the heat receiving portion and a second opening that opens toward the heat radiating portion. The second pipe portion has a third opening that opens toward the heat receiving portion and a fourth opening that opens toward the heat radiating portion. The center of the first opening is located above the center of the third opening, and the center of the second opening is located above the center of the fourth opening.

[0007] A boiling cooling device according to one aspect of the present invention includes a heat receiving portion that stores a refrigerant and receives heat from a heating element, a heat radiating container, a heat radiating portion that radiates heat from the heat receiving portion, a first pipe portion having a first flow path that transports a vapor-phase refrigerant generated by vaporizing the refrigerant in the heat receiving portion to the heat radiating portion, and a second pipe portion having a second flow path that transports a liquid-phase refrigerant generated by condensing the vapor-phase refrigerant in the heat radiating portion to the heat receiving portion. A part of the first pipe portion is located in the heat radiating container. The first pipe portion has a first opening that opens toward the heat receiving portion, a second opening located in the heat radiating container, and a fifth opening located in the heat radiating container. The second pipe portion has a third opening that opens toward the heat receiving portion and a fourth opening that opens toward the heat radiating portion. Each of the second opening and the fifth opening opens to the side of the first pipe portion.

[0008] A method for cooling a heating element according to an aspect of the present invention uses a boiling cooling device including a heat receiving portion that stores a refrigerant and receives heat from the heating element, a heat radiating portion that has a heat radiating container and radiates heat from the heat receiving portion, a first pipe portion having a first flow path that transports a vapor-phase refrigerant generated by vaporization of the refrigerant in the heat receiving portion to the heat radiating portion, and a second pipe portion having a second flow path that transports a liquid-phase refrigerant generated by condensation of the vapor-phase refrigerant in the heat radiating portion to the heat receiving portion. The method includes arranging the heat radiating container to be inclined with respect to a horizontal plane, positioning the center of the first opening above the center of the third opening, and positioning the center of the second opening above the center of the fourth opening, wherein each of the center line of the first flow path and the center line of the second flow path extends linearly. The first pipe portion has a first opening that opens toward the heat receiving portion and a second opening that opens toward the heat radiating portion. The second pipe portion has a third opening that opens toward the heat receiving portion and a fourth opening that opens toward the heat radiating portion.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Embodiments for Carrying Out the Invention

[0010] Hereinafter, preferred embodiments according to the present invention will be described with reference to the accompanying drawings. Note that the dimensions or scales of each part in the drawings are appropriately different from the actual ones, and there are also parts schematically shown for easy understanding. Further, the scope of the present invention is not limited to these embodiments unless otherwise specified in the following description.

[0011] 1. First Embodiment 1-1. Outline of the Boiling Cooling Device 1 FIG. 1 is a cross-sectional perspective view showing a schematic configuration of the boiling cooling device 1 according to the first embodiment. FIG. 2 is a plan view of the boiling cooling device 1 shown in FIG. 1. Note that in FIG. 1, a cross-section taken along line B-B in FIG. 2 is shown. Further, hereinafter, for convenience of explanation, the X-axis, Y-axis, and Z-axis orthogonal to each other will be appropriately used for explanation. Also, one direction along the X-axis is defined as the X1 direction, and the direction opposite to the X1 direction is defined as the X2 direction. One direction along the Y-axis is defined as the Y1 direction, and the direction opposite to the Y1 direction is defined as the Y2 direction. One direction along the Z-axis is defined as the Z1 direction, and the direction opposite to the Z1 direction is defined as the Z2 direction. Also, viewing in the Z1 direction or Z2 direction is referred to as a plan view.

[0012] The boiling cooling device 1 shown in FIGS. 1 and 2 is used, for example, for cooling power electronics products such as inverters or rectifiers mounted on railway vehicles, automobiles, or household electrical appliances. The power electronics product has, for example, a power semiconductor element such as a diode or an IGBT (Insulated Gate Bipolar Transistor). The power semiconductor element is an example of a heat-generating body that is an object to be cooled in the boiling cooling device 1.

[0013] Further, the boiling cooling device 1 is a cooler of a loop type thermosiphon that utilizes the density difference between the vaporized refrigerant RE and the liquefied refrigerant RE. The boiling cooling device 1 is used for cooling the heating element in an inclined state with respect to the horizontal plane. That is, the boiling cooling device 1 is used in an inclined state with respect to the vertical line.

[0014] The boiling cooling device 1 shown in FIG. 1 includes a heat receiving portion 10, a heat radiating portion 20, and a heat transport portion 30. The heat transport portion 30 includes a first pipe portion 31 and a second pipe portion 32. Further, the heat radiating portion 20 is located in the Z1 direction with respect to the heat receiving portion 10, and the heat receiving portion 10 and the heat radiating portion 20 are connected via the heat transport portion 30. Hereinafter, each portion will be described.

[0015] 1-1a. Heat receiving portion 10 The heat receiving portion 10 shown in FIG. 1 has a housing chamber S10 and is a structure that receives heat from a heating element (not shown). The housing chamber S10 is a space for housing the liquid refrigerant RE. In the heat receiving portion 10, a vapor-phase refrigerant is generated by vaporizing the refrigerant RE by the heat of a heating element (not shown).

[0016] In the example shown in FIG. 1, the heat receiving portion 10 has a box shape forming the housing chamber S10. The heat receiving portion 10 includes a bottom plate 11, a top plate 12, and side walls 13. The space surrounded by the bottom plate 11, the top plate 12, and the side walls 13 is the housing chamber S10. Each of the bottom plate 11 and the top plate 12 is a flat plate extending in a direction orthogonal to the Z axis. The side walls 13 are located between the bottom plate 11 and the top plate 12 and connect the outer peripheries of the bottom plate 11 and the top plate 12 over the entire circumference. Note that the bottom plate 11 and the side walls 13 are integral in the illustrated example. Further, the side walls 13 extend along the Z axis. In the illustrated example, the side walls 13 are orthogonal to the bottom plate 11, but they do not have to be orthogonal to the bottom plate 11. Also, the top plate 12 has a hole into which the aforementioned first pipe portion 31 of the heat transport portion 30 is inserted and a hole into which the second pipe portion 32 of the heat transport portion 30 is inserted.

[0017] The heat receiving part 10 is made of a material with excellent thermal conductivity. Specific materials for the bottom plate 11, the top plate 12, and the side wall 13 include, for example, metal materials such as copper, aluminum, or alloys of any of these. The materials of the bottom plate 11, the top plate 12, and the side wall 13 may be the same as or different from each other. Note that each of the bottom plate 11, the top plate 12, and the side wall 13 may be composed of separate members, or the bottom plate 11, the top plate 12, and the side wall 13 may be integrally formed.

[0018] Such a heat receiving part 10 is thermally connected to a heating element (not shown). "Thermally connected" means satisfying any one of the following conditions a, b, or c. Condition a: Two members are physically in direct contact. Condition b: Two members are arranged with a gap of 50 μm or less therebetween. Condition c: Two members are physically connected through another member with a thermal conductivity of 10 W·m -1 ·K -1 or more. Note that between the two members in each condition, heat transfer grease, an adhesive, etc. may be present. In this case, from the viewpoint of enhancing thermal conductivity, the adhesive preferably contains a thermally conductive filler or the like.

[0019] The refrigerant RE is not particularly limited, and examples thereof include water-based refrigerants such as water, alcohol-based refrigerants such as methanol, ketone-based refrigerants such as acetone, glycol-based refrigerants such as ethylene glycol, fluorocarbon-based refrigerants such as fluorinate, chlorofluorocarbon-based refrigerants such as HFC134a, and hydrocarbon-based refrigerants such as butane. Note that surfactants such as fluorine-based surfactants, silicone-based surfactants, or hydrocarbon-based surfactants may be added to the refrigerant RE as necessary. Also, the refrigerant RE may be a combination of two or more of the aforementioned refrigerants.

[0020] 1-1b. Heat dissipation part 20 The heat radiating part 20 shown in Fig. 1 is a structure that radiates heat from the heat receiving part 10. The heat radiating part 20 has a condensation chamber S20 which is a space for condensing and liquefying the refrigerant RE from a vaporized state. In the heat radiating part 20, the vapor-phase refrigerant generated in the heat receiving part 10 is condensed to generate a liquid-phase refrigerant. Specifically, in the heat radiating part 20, the refrigerant RE in the condensation chamber S20 exchanges heat with an external fluid to radiate the heat from the heat receiving part 10 to the outside, thereby condensing and liquefying the vapor-phase refrigerant. The external fluid is not particularly limited and may be a liquid or a gas, but typically, for example, it is air.

[0021] In the example shown in Fig. 1, the heat radiating part 20 has a heat radiating container 21 and a plurality of heat radiating fins 22. The heat radiating container 21 is a box-shaped member that forms the condensation chamber S20. In the illustrated example, the heat radiating container 21 is a vertically long container with the longitudinal direction in the Z1 direction. The cooling of the heating element by the boiling cooling device 1 is performed, for example, with the heat radiating container 21 inclined with respect to the horizontal plane.

[0022] The heat radiating container 21 has a bottom plate 211, a top plate 212, and a cylindrical part 213. The space surrounded by the bottom plate 211, the top plate 212, and the cylindrical part 213 is the condensation chamber S20. The bottom plate 211 and the top plate 212 are arranged parallel to each other. Each of the bottom plate 211 and the top plate 212 is a flat plate that extends in a direction perpendicular to the Z-axis. The cylindrical part 213 is located between the bottom plate 211 and the top plate 212 and connects the outer peripheries of the bottom plate 211 and the top plate 212 over the entire circumference. The cylindrical part 213 extends along the Z-axis. In the illustrated example, the cylindrical part 213 is perpendicular to the bottom plate 211, but it does not have to be perpendicular. Also, the bottom plate 211 has a hole into which the first pipe part 31, which will be described later, of the heat transport part 30 is inserted, and a hole into which the second pipe part 32 of the heat transport part 30 is inserted.

[0023] The shape of the condensation chamber S20 of the heat radiating container 21 is cylindrical, but it may be, for example, prismatic. Also, as shown in FIG. 2, the shape of the condensation chamber S20 in plan view is circular, but it may be, for example, polygonal. Further, the heat radiating container 21 is made of a material having excellent thermal conductivity. Specific examples of the material of the heat radiating container 21 include metal materials such as copper, aluminum, or an alloy of any of these. In the illustrated example, the bottom plate 11, the top plate 12, and the side wall 13 are integrally formed, but each of the bottom plate 11, the top plate 12, and the side wall 13 may be formed of separate members.

[0024] Each heat radiating fin 22 shown in FIG. 1 is thermally connected to the heat radiating container 21. Each heat radiating fin 22 is a flat plate-like member. In the illustrated example, each heat radiating fin 22 extends in a direction perpendicular to the Z axis. Also, the plurality of heat radiating fins 22 are arranged at intervals in the thickness direction. Each heat radiating fin 22 of the present embodiment is arranged so as to overlap substantially the entire range of the heat receiving portion 10 in plan view. Further, each heat radiating fin 22 has a hole for inserting a plurality of heat radiating containers 21. Each heat radiating fin 22 is made of a material having excellent thermal conductivity. Specific examples of the material of the heat radiating fin 22 include metal materials such as copper, aluminum, or an alloy of any of these. Also, for example, the heat radiating fin 22 is fixed to the heat radiating container 21 by means of tube expansion, press fitting, adhesive, screwing, brazing, or welding.

[0025] Note that the shape of the heat radiating fin 22 is not limited to the example shown in FIG. 1 and is arbitrary. Also, the heat radiating fin 22 may be provided as necessary or may be omitted. However, by having a plurality of heat radiating fins 22 in the heat radiating portion 20, the gas of the refrigerant RE can be efficiently condensed and liquefied.

[0026] 1-1c. Heat transport section 30 The heat transport section 30 shown in FIG. 1 is a structure that transports heat from the heat receiving portion 10 to the heat radiating portion 20 using the movement of the refrigerant RE. In the example shown in FIG. 1, the heat transport section 30 has a first pipe section 31 and a second pipe section 32. Note that the top plate 12 of the heat receiving portion 10 described above may also serve as a part of the heat transport section 30.

[0027] The first pipe portion 31 transports the vapor-phase refrigerant generated by vaporizing the refrigerant RE in the heat receiving portion 10 to the heat radiating portion 20. In the present embodiment, the first pipe portion 31 is composed of a pipe linearly extending along the Z axis. Further, the first pipe portion 31 is connected to each of the heat receiving portion 10 and the heat radiating portion 20. Specifically, the first pipe portion 31 is connected to the top plate 12 of the heat receiving portion 10 and the bottom plate 211 of the heat radiating portion 20, respectively.

[0028] The second pipe portion 32 transports the liquid-phase refrigerant generated by condensing the vapor-phase refrigerant in the heat radiating portion 20 to the heat receiving portion 10. In the present embodiment, the second pipe portion 32 is composed of a pipe linearly extending along the Z axis. Further, the second pipe portion 32 is connected to each of the heat receiving portion 10 and the heat radiating portion 20. Specifically, the second pipe portion 32 is connected to the top plate 12 of the heat receiving portion 10 and the bottom plate 211 of the heat radiating portion 20, respectively. Also, in the example shown in FIG. 2, the first pipe portion 31 and the second pipe portion 32 are arranged side by side in the direction along the X axis.

[0029] The first pipe portion 31 and the second pipe portion 32 are made of a material having excellent thermal conductivity. Specific constituent materials of the first pipe portion 31 and the second pipe portion 32 include, for example, metal materials such as copper, aluminum, or an alloy of any of these. Further, the first pipe portion 31 and the second pipe portion 32 are fixed to the top plate 12 by brazing or the like. Note that the first pipe portion 31 and the second pipe portion 32 may be made of the same material as each other, or may be made of different materials from each other.

[0030] The boiling cooling device 1 having the above-described schematic configuration is a cooler of a thermosiphon as described above. In the boiling cooling device 1, the vapor-phase refrigerant generated by vaporizing the refrigerant RE in the heat-receiving part 10 is introduced from the first pipe part 31 to the heat-radiating part 20 due to the density difference between the gas and the liquid. The vapor-phase refrigerant is condensed and liquefied in the heat-radiating part 20 to generate a liquid-phase refrigerant. The liquid-phase refrigerant is introduced from the second pipe part 32 to the heat-receiving part 10 by gravity. Then, the liquid-phase refrigerant is vaporized again to become a vapor-phase refrigerant. By forming a circulation flow involving the phase change of the refrigerant RE in this way, heat transport by latent heat is performed from the heat-receiving part 10 to the heat-radiating part 20. According to such a cooler of a thermosiphon, the refrigerant RE can be circulated without using a pump.

[0031] 1-1d. Detailed configuration of the heat transport part 30 FIG. 3 is a longitudinal sectional view showing the heat transport part 30 shown in FIG. 1, that is, a sectional view taken along line B-B in FIG. 2. For example, as shown in FIG. 3, when the boiling cooling device 1 is used for cooling a heating element, the boiling cooling device 1 is placed at a predetermined position such that the center line A0 of the heat-radiating container 21 is inclined with respect to the vertical line A. In this specification, each of the vertically upward direction and the vertically obliquely upward direction is referred to as "upward". Each of the vertically downward direction and the vertically obliquely downward direction is referred to as "downward".

[0032] As shown in FIG. 3, the first pipe part 31 and the second pipe part 32 are arranged parallel to each other. Specifically, the center line A1 of the first flow path S1 of the first pipe part 31 and the center line A2 of the second flow path S2 of the second pipe part 32 are parallel to each other.

[0033] The first pipe part 31 is connected to each of the heat-receiving part 10 and the heat-radiating part 20, and opens into each of the accommodation chamber S10 and the condensation chamber S20. The first pipe part 31 has a first inner wall surface 310 that forms the first flow path S1. The first flow path S1 is a space for transporting the vapor-phase refrigerant generated by vaporizing the refrigerant RE in the heat-receiving part 10 to the heat-radiating part 20. Each condensation chamber S20 communicates with the accommodation chamber S10 of the heat-receiving part 10 via the first flow path S1.

[0034] In the illustrated example, the thickness of the first pipe portion 31 is constant. The first inner wall surface 310 of the first pipe portion 31 is a cylindrical surface parallel to the center line A1 of the first flow path S1. The inner diameter of the first inner wall surface 310 is constant. Therefore, the cross-sectional area of the first flow path S1 is constant.

[0035] The first pipe portion 31 has a first opening 301 that opens toward the heat receiving portion 10 and a second opening 302 that opens toward the heat radiating portion 20. The first opening 301 is a space surrounded by the end of the first inner wall surface 310 in the Z2 direction. The second opening 302 is a space surrounded by the end of the first inner wall surface 310 in the Z1 direction. The shapes of the first opening 301 and the second opening 302 in plan view are circular.

[0036] The position of the first opening 301 in the Z1 direction is the same as the position of the lower surface of the top plate 12 in the Z1 direction. However, the first opening 301 may be located in the Z2 direction with respect to the lower surface of the top plate 12, for example. Also, the first opening 301 is located above the liquid level RE0 of the refrigerant RE present in the storage chamber S10. In other words, the first opening 301 is located between the liquid level RE0 and the heat radiating portion 20. Therefore, the first opening 301 is not in contact with the liquid level RE0.

[0037] The position of the second opening 302 in the Z1 direction is the same as the position of the upper surface of the bottom plate 211 in the Z1 direction. However, the second opening 302 may be located in the Z1 direction with respect to the bottom plate 211 of the heat radiating container 21.

[0038] As shown in FIG. 3, the second pipe portion 32 is connected to each of the heat receiving portion 10 and the heat radiating portion 20 and opens into each of the storage chamber S10 and the condensation chamber S20. Each second pipe portion 32 has a second inner wall surface 320 that forms a second flow path S2. The second flow path S2 is a space for transporting the liquid-phase refrigerant generated by condensing the vapor-phase refrigerant in the heat radiating portion 20 to the heat receiving portion 10. Through the second flow path S2, the condensation chamber S20 of each heat radiating container 21 communicates with the storage chamber S10 of the heat receiving portion 10.

[0039] In the illustrated example, the thickness of the second pipe portion 32 is constant. The second inner wall surface 320 of the second pipe portion 32 is a cylindrical surface parallel to the center line A2 of the second flow path S2. The inner diameter of the second inner wall surface 320 is constant. Therefore, the cross-sectional area of the second flow path S2 is constant.

[0040] The second pipe portion 32 has a third opening 303 that opens toward the heat receiving portion 10 and a fourth opening 304 that opens toward the heat radiating portion 20. The third opening 303 is a space surrounded by the end of the second inner wall surface 320 in the Z2 direction. The fourth opening 304 is a space surrounded by the end of the second inner wall surface 320 in the Z1 direction. The shapes of the third opening 303 and the fourth opening 304 in plan view are circular.

[0041] The position of the third opening 303 in the Z1 direction is the same as the position of the lower surface of the top plate 12 in the Z1 direction. However, the third opening 303 may be located in the Z2 direction with respect to the lower surface of the top plate 12, for example. In the present embodiment, the third opening 303 is located above the liquid level RE0 of the refrigerant RE existing in the accommodation chamber S10. In other words, the third opening 303 is located between the liquid level RE0 and the heat radiating portion 20. Therefore, the third opening 303 does not contact the liquid level RE0.

[0042] The position of the fourth opening 304 in the Z1 direction is the same as the position of the upper surface of the bottom plate 211 in the Z1 direction, for example. However, the fourth opening 304 may be located in the Z1 direction with respect to the bottom plate 211 of the heat radiating container 21.

[0043] Also, in the illustrated example, the average cross-sectional area of the first flow path S1 of the first pipe portion 31 described above is larger than the average cross-sectional area of the second flow path S2 of the second pipe portion 32. For this reason, compared with the case where the cross-sectional areas of the first flow path S1 and the second flow path S2 are the same, the vapor-phase refrigerant easily flows through the first flow path S1, and the liquid-phase refrigerant easily flows through the second flow path S2. Therefore, the boiling cooling device 1 can function suitably as a loop-type thermosiphon.

[0044] Also, as described above, the first pipe portion 31 and the second pipe portion 32 are pipes extending linearly. Therefore, each of the center line A1 of the first flow path S1 and the center line A2 of the second flow path S2 extends linearly. For this reason, compared with the case where the first pipe portion 31 and the second pipe portion 32 are bent, the flow path resistance in the first flow path S1 and the second flow path S2 can be reduced. Thus, it becomes difficult to inhibit the circulation of the refrigerant RE. Therefore, the refrigerant RE can be circulated smoothly. Also, processing such as bending is not required during the manufacture of each of the first pipe portion 31 and the second pipe portion 32. For this reason, each of the first pipe portion 31 and the second pipe portion 32 can be manufactured at low cost.

[0045] Also, as described above, when the boiling cooling device 1 is used for cooling the heating element, the boiling cooling device 1 is placed at a predetermined location such that the heat radiation container 21 is arranged to be inclined with respect to the vertical line A. Specifically, the boiling cooling device 1 is placed at a predetermined location such that the bottom plate 211, the top plate 212, and the cylindrical portion 213 of the heat radiation container 21 are each inclined with respect to the vertical line A or the horizontal plane G0. Also, along with the inclination of the heat radiation container 21, the first pipe portion 31, the second pipe portion 32, and the bottom plate 11, the top plate 12, and the side wall 13 of the heat receiving portion 10 are inclined in the same direction as the heat radiation container 21 with respect to the vertical line A.

[0046] Here, the vapor-phase refrigerant in the heat radiation container 21 is cooled on the inner wall surface of the heat radiation container 21 by contact with the heat radiation container 21 cooled by the outside air, and becomes a liquid-phase refrigerant while releasing latent heat. The liquid-phase refrigerant becomes a liquid film F0 in the heat radiation container 21. The liquid film F0 flows downward along the upper surface of the bottom plate 211 and the inner wall surface of the cylindrical portion 213. As a result, the thickness of the liquid film F0 increases as it goes downward in the heat radiation container 21. The thicker the liquid film F0, the greater the thermal resistance. For this reason, in the thick portion of the liquid film F0, the cooling performance deteriorates due to a decrease in the efficiency of condensation heat transfer compared to the thin portion of the liquid film F0.

[0047] In this embodiment, in order to suppress the decrease in the cooling performance due to the influence of such a liquid film F0, the heat radiating container 21 is in an inclined state with respect to the vertical line A, and the second opening 302 is located above the fourth opening 304. Specifically, the center O2 of the second opening 302 is located above the center O4 of the fourth opening 304.

[0048] Since the center O2 is located above the center O4, the second opening 302 is less likely to be blocked by the liquid film F0 than when the center O2 is located below the center O4. Therefore, a decrease in the momentum of the vapor flow due to the vapor-phase refrigerant ejected from the second opening 302 is suppressed. Therefore, the liquid film F0 in the heat radiating container 21 can be efficiently disturbed by the vapor flow. As a result, thickening of the liquid film F0 can be suppressed, and thus an increase in the thermal resistance of the liquid film F0 can be suppressed. Therefore, a decrease in the efficiency of the condensation heat transfer can be suppressed, and thus a decrease in the cooling performance can be suppressed. In particular, since the entire second opening 302 is located above the entire fourth opening 304, a decrease in the cooling performance can be effectively suppressed.

[0049] Furthermore, since the center O4 is located below the center O2, the liquid-phase refrigerant in the heat radiating container 21 is more likely to flow into the fourth opening 304 than when the center O4 is located above the center O2. Therefore, the refrigerant RE can be circulated smoothly.

[0050] Also, in a state where the heat radiating container 21 is inclined with respect to the vertical line A, the center O1 of the first opening 301 is located above the center O3 of the third opening 303. For this reason, compared with the case where the center O1 is located below the center O3, the first opening 301 is less likely to be blocked by the liquid refrigerant RE, so the vapor-phase refrigerant is more likely to flow into the first opening 301. Therefore, the refrigerant RE can be circulated smoothly. Also, since the entire first opening 301 is located above the entire third opening 303, the vapor-phase refrigerant is particularly likely to flow into the first opening 301

[0051] Note that the inclination angle θ of the heat dissipation container 21 is not particularly limited. For example, it is greater than 0° and less than 45°. The inclination angle θ is the angle formed by the center line A0 of the heat dissipation container 21 and the vertical line A.

[0052] Also, the center line A1 of the first flow path S1 is located above the center line A2 of the second flow path S2. Therefore, it is easier to position the second opening 302 above the fourth opening 304 than when the center line A1 is located below the center line A2.

[0053] Also, as described above, the heat dissipation part 20 has heat dissipation fins 22 that are thermally connected to the heat dissipation container 21. And the heat dissipation fins 22 are inclined with respect to the vertical line A. Therefore, compared with the case where the heat dissipation fins 22 are arranged along the horizontal plane G0 orthogonal to the vertical line A, the heat dissipation container 21 can be cooled efficiently. If the heat dissipation fins 22 are parallel to the horizontal plane G0, even if the air heated between the heat dissipation fins 22 tries to rise, the movement of the air is hindered by the heat dissipation fins 22. Thus, heat is likely to stay between the heat dissipation fins 22, and natural retention is difficult to occur. On the other hand, since the heat dissipation fins 22 are inclined with respect to the horizontal plane G0, compared with the case where they are not inclined, the air heated between the heat dissipation fins 22 can be easily moved upward along the heat dissipation fins 22, so that the retention of heat between the heat dissipation fins 22 can be suppressed. Therefore, the cooling performance inside the heat dissipation container 21 can be enhanced.

[0054] Note that the heat dissipation fins 22 may be inclined with respect to the plane orthogonal to the center line A0. However, from the viewpoint of ease of assembly of the heat dissipation part 20, it is preferable that the heat dissipation fins 22 are inclined with respect to the vertical line A along with the inclination of the heat dissipation container 21. Specifically, it is preferable that the heat dissipation fins 22 are parallel to the plane orthogonal to the center line A0, that is, parallel to the bottom plate 211. Thereby, the assembly of the heat dissipation container 21 and the heat dissipation fins 22 is easy, and the heat dissipation fins 22 can be easily inclined along with the inclination of the heat dissipation container 21.

[0055] 2. Second Embodiment Next, a second embodiment of the present invention will be described. For elements whose operations and functions are the same as those in the first embodiment in the forms exemplified below, the reference numerals used in the description of the first embodiment are reused, and the detailed description of each is omitted as appropriate.

[0056] FIG. 4 is a longitudinal sectional view showing the boiling cooling device 1A of the second embodiment. FIG. 5 is a cross-sectional view of the boiling cooling device 1A of the second embodiment and corresponds to the cross-section taken along line C-C in FIG. 4. The boiling cooling device 1A shown in FIGS. 4 and 5 is the same as the heat transport section 30 of the first embodiment, except that it has a heat transport section 30A instead of the heat transport section 30 of the first embodiment. Hereinafter, the differences between the heat transport section 30A and the heat transport section 30 will be described, and the description of the same matters as those of the heat transport section 30 will be omitted.

[0057] As shown in FIG. 4, the heat transport section 30A has a first pipe section 31A and a second pipe section 32. A part of the first pipe section 31A is located in the heat dissipation container 21 such that the end of the first pipe section 31A in the Z1 direction is located in the Z1 direction relative to the bottom plate 211 of the heat dissipation container 21. The first pipe section 31A has a plurality of openings. Specifically, the first pipe section 31A has a second opening 302A and a fifth opening 305. Each of the second opening 302A and the fifth opening 305 is a hole penetrating the pipe wall of the first pipe section 31A. Note that no opening is provided at the end of the first pipe section 31A in the Z1 direction, and the end is closed.

[0058] As shown in FIG. 5, each of the second opening 302A and the fifth opening 305 opens to the side of the first pipe section 31A. Specifically, the second opening 302A opens in the X2 direction. The fifth opening 305 opens in the X1 direction. Therefore, the second opening 302A and the fifth opening 305 open in opposite directions. In a state where the heat dissipation container 21 is inclined, the center O5 of the fifth opening 305 is located below the center O2 of the second opening 302A. Also, each of the center O2 of the second opening 302A and the center O5 of the fifth opening 305 is located above the center O4 of the fourth opening 304.

[0059] Also in this embodiment, similar to the first embodiment, the center O2 of the second opening 302A is located above the center O4 of the fourth opening 304. Therefore, compared with the case where the center O2 is located below the center O4, the second opening 302A is less likely to be blocked by the liquid film F0. Thus, the liquid film F0 in the heat radiating container 21 can be efficiently disturbed by the vapor flow. Therefore, a decrease in the efficiency of condensation heat transfer can be suppressed, and a decrease in cooling performance can be suppressed.

[0060] Further, as described above, a part of the first pipe portion 31A is located inside the heat radiating container 21. In other words, a part of the first pipe portion 31A protrudes from the bottom plate 211 in the Z1 direction. Therefore, compared with the case where a part of the first pipe portion 31A does not protrude from the bottom plate 211, the second opening 302A is less likely to be blocked by the liquid film F0. Therefore, the liquid film F0 in the heat radiating container 21 can be efficiently disturbed by the vapor flow.

[0061] Furthermore, as described above, in addition to the second opening 302A, the first pipe portion 31A has a fifth opening 305. By having a plurality of openings in the first pipe portion 31A, the liquid film F0 in the heat radiating container 21 can be efficiently disturbed by the vapor flow generated by the gaseous refrigerant ejected from the first pipe portion 31A, compared with the case where only one opening is provided.

[0062] Also, the second opening 302A and the fifth opening 305 open to the side of the first pipe portion 31A. Therefore, compared with the case where the upper end of the first pipe portion 31A opens, the liquid film F0 in the heat radiating container 21 can be efficiently disturbed by the vapor flow.

[0063] Also, when the second opening 302A and the fifth opening 305 open to the side of the first pipe portion 31A, it is preferable that no opening is provided at the upper end of the first pipe portion 31A. By not providing an opening at the upper end, the liquid film F0 in the heat radiating container 21 can be efficiently disturbed by the vapor flow generated by the gaseous refrigerant ejected from the second opening 302A and the fifth opening 305.

[0064] Since the second opening 302A and the fifth opening 305 open to the side of the first pipe portion 31A, the liquid film F0 can be efficiently disturbed by the vapor flow regardless of whether the heat dissipation container 21 is inclined with respect to the vertical line A or not. Therefore, even when the heat dissipation container 21 is not inclined with respect to the vertical line A, the cooling performance can be improved.

[0065] Further, in a state where the heat dissipation container 21 is inclined with respect to the vertical line A, the second opening 302A faces downward. Specifically, the second opening 302A faces obliquely downward in the vertical direction. Since the second opening 302A faces downward, the vapor-phase refrigerant can be injected from the second opening 302A toward the lower portion in the heat dissipation container 21 where the thickness of the liquid film F0 is the thickest. For this reason, the liquid film F0 in the heat dissipation container 21 can be more efficiently disturbed by the vapor flow generated by the vapor-phase refrigerant.

[0066] On the other hand, in a state where the heat dissipation container 21 is inclined with respect to the vertical line A, the fifth opening 305 faces upward. Specifically, the fifth opening 305 faces obliquely upward in the vertical direction. For this reason, while the second opening 302A faces downward, the fifth opening 305 faces upward, so that the liquid film F0 in the heat dissipation container 21 can be more efficiently disturbed by the vapor flow than when the fifth opening 305 faces downward. That is, since the fifth opening 305 and the second opening 302A face in opposite directions, the liquid film F0 in the heat dissipation container 21 can be more efficiently disturbed by the vapor flow than when they face in the same direction.

[0067] The fifth opening 305 is located below the second opening 302A. And the opening area, i.e., the cross-sectional area, of the fifth opening 305 is larger than the opening area, i.e., the cross-sectional area, of the second opening 302A. Therefore, since the cross-sectional area of the fifth opening 305 is larger than that of the second opening 302A, the amount of the vapor flow caused by the vapor-phase refrigerant jetted from the fifth opening 305 can be increased as compared with the case where the cross-sectional area of the fifth opening 305 is smaller. Also, since the fifth opening 305 is located below the second opening 302A, the vapor-phase refrigerant can be jetted from the fifth opening 305 toward the lower portion in the heat radiating container 21 where the thickness of the liquid film F0 is the thickest.

[0068] Note that since the cross-sectional area of the fifth opening 305 is larger than that of the second opening 302A, the liquid film F0 in the heat radiating container 21 can be efficiently disturbed by the vapor flow not only when the heat radiating container 21 is inclined with respect to the vertical line A but also when it is not inclined. Therefore, even when the heat radiating container 21 is not inclined with respect to the vertical line A, the cooling performance can be improved.

[0069] FIG. 6 is a diagram showing another example of the first pipe portion 31A shown fifth. The first pipe portion 31A shown in FIG. 6 has three or more openings. Specifically, the first pipe portion 31A has a sixth opening 306 and a seventh opening 307 in addition to the second opening 302A and the fifth opening 305. The sixth opening 306 opens in the Y1 direction. The seventh opening 307 opens in the Y2 direction. By having a plurality of openings, the liquid film F0 in the heat radiating container 21 can be more efficiently disturbed by the vapor flow. Also, in the example shown in FIG. 6, the directions in which the plurality of openings open in a plan view are different from each other. Therefore, the liquid film F0 can be more efficiently disturbed as compared with the case where the plurality of openings open in the same direction as each other. Also, the positions of the plurality of openings on the vertical line A and in the Z1 direction are different from each other. Therefore, the liquid film F0 can be more efficiently disturbed as compared with the case where the positions of the plurality of openings on the vertical line A and in the Z1 direction are the same as each other.

[0070] 3. Third Embodiment Hereinafter, a third embodiment of the present invention will be described. For elements whose operations and functions are the same as those in the first embodiment in the forms exemplified below, the reference numerals used in the description of the first embodiment are reused, and the detailed descriptions of each are appropriately omitted.

[0071] FIG. 7 is a longitudinal sectional view showing a boiling cooling device 1B according to the third embodiment. The boiling cooling device 1B shown in FIG. 7 is the same as the heat transport section 30 of the first embodiment, except that it has a heat transport section 30B instead of the heat transport section 30 of the first embodiment. Hereinafter, the differences between the heat transport section 30B and the heat transport section 30 will be described, and the description of the same matters as those of the heat transport section 30 will be omitted.

[0072] As shown in FIG. 7, the heat transport section 30B has a first pipe section 31B and a second pipe section 32B. A part of the first pipe section 31B is located inside the heat dissipation container 21. In other words, a part of the first pipe section 31B protrudes upward with respect to the bottom plate 211.

[0073] A part of the second pipe section 32B is located inside the heat receiving section 10. In other words, a part of the second pipe section 32B protrudes downward with respect to the top plate 12. Further, the third opening 303B is located below the liquid level RE0 of the refrigerant RE existing in the accommodation chamber S10. In other words, the third opening 303B is in contact with the liquid refrigerant RE.

[0074] Also in this embodiment, similar to the first embodiment, the center O2 of the second opening 302B is located above the center O4 of the fourth opening 304B of the second pipe section 32B. For this reason, compared with the case where the center O2 is located below the center O4, the second opening 302B is less likely to be blocked by the liquid film F0. Therefore, the liquid film F0 in the heat dissipation container 21 can be efficiently disturbed by the vapor flow caused by the injection of the vapor-phase refrigerant from the second opening 302B. Therefore, a decrease in cooling performance can be suppressed.

[0075] Also, as described above, a part of the first pipe portion 31B is located within the heat dissipation container 21. Since a part of the first pipe portion 31B protrudes from the bottom plate 211 in the Z1 direction, the second opening 302B is less likely to be blocked by the liquid film F0 than when a part of the first pipe portion 31B does not protrude from the bottom plate 211. Therefore, the steam flow can more efficiently disturb the liquid film F0.

[0076] Also, in the present embodiment, the cross-sectional area of the first flow path S1 of the first pipe portion 31B is substantially equal to the cross-sectional area of the second flow path S2 of the second pipe portion 32B. In this case, since a part of the first pipe portion 31B is located within the heat dissipation container 21, it is easier to position the position of the second opening 302B on the vertical line A upward than when a part is not located within the heat dissipation container 21. Therefore, the inflow of the liquid-phase refrigerant into the first pipe portion 31B is more suppressed. For this reason, compared with the fourth opening 304, it is more difficult for the liquid-phase refrigerant to flow into the second opening 302B.

[0077] Also, as described above, the third opening 303B of the second pipe portion 32B is located below the first opening 301 of the first pipe portion 31. Therefore, the third opening 303B is more likely to come into contact with the refrigerant RE than the first opening 301. On the other hand, the first opening 301 of the first pipe portion 31B is less likely to come into contact with the refrigerant RE. For this reason, compared with the first pipe portion 31B, the liquid-phase refrigerant from the heat dissipation portion 20 is more likely to flow down to the second pipe portion 32B, and the vapor-phase refrigerant of the heat receiving portion 10 is more likely to flow into the first pipe portion 31B. Therefore, the refrigerant RE can be circulated more smoothly.

[0078] 4. Modification The embodiments illustrated above can be variously modified. Specific modification modes applicable to the above-described embodiments are illustrated below. Two or more modes arbitrarily selected from the following illustrations can be appropriately combined within a range that does not conflict with each other. Also, the following modification examples regarding the first embodiment can be appropriately combined with the second or third embodiment within a non-conflicting range.

[0079] 4-1. First Modification In the first embodiment, the first pipe portion 31 and the second pipe portion 32 are arranged in the X1 direction, but they may be arranged in a direction intersecting the Z axis, and they may be arranged in a direction other than the X1 direction.

[0080] FIG. 8 is a cross-sectional view showing the first pipe portion 31 and the second pipe portion 32 in the first modification. The first pipe portion 31 and the second pipe portion 32 shown in FIG. 8 are arranged in a direction intersecting both the X1 direction and the Y1 direction in a plan view. Note that the second opening 302 and the fourth opening 304 are arranged in a direction intersecting both the X1 direction and the Y1 direction in a plan view. Also, the first pipe portion 31 and the second pipe portion 32 shown in FIG. 8 do not overlap each other in the X1 direction and the Y1 direction. Also in the example shown in FIG. 8, similar to the first embodiment, with the heat dissipation container 21 inclined with respect to the vertical line A, by positioning the center line A1 of the first pipe portion 31 above the center line A2 of the second pipe portion 32 on the vertical line A, a decrease in cooling performance can be suppressed.

[0081] FIG. 9 is a view showing another example of the first pipe portion 31 in FIG. 8. The first pipe portion 31 and the second pipe portion 32 shown in FIG. 9 have portions overlapping each other in the Y1 direction. Note that the second opening 302 and the fourth opening 304 have portions overlapping each other in the Y1 direction. Also in the example shown in FIG. 9, similar to the first embodiment, with the heat dissipation container 21 inclined with respect to the vertical line A, by positioning the center line A1 of the first pipe portion 31 above the center line A2 of the second pipe portion 32 on the vertical line A, a decrease in cooling performance can be suppressed.

[0082] 4-2. Second Modification In the above-described first embodiment, one heat receiving portion 10 is provided with one heat dissipation container 21, one first pipe portion 31, and one second pipe portion 32. However, a plurality of heat dissipation containers 21, a plurality of first pipe portions 31, and a plurality of second pipe portions 32 may be provided for one heat receiving portion 10.

[0083] FIG. 10 is a cross-sectional perspective view showing a schematic configuration of the boiling cooling device 1C in the second modification. As shown in FIG. 10, the boiling cooling device 1C includes a heat receiving part 10, a heat radiating part 20C, and a heat transport part 30C. The heat radiating part 20C has a plurality of heat radiating containers 21. The heat transport part 30C has a plurality of first pipe parts 31C and a plurality of second pipe parts 32C. Each of the first pipe part 31C and the second pipe part 32C is provided for each heat radiating container 21. The plurality of first pipe parts 31C and the plurality of second pipe parts 32C are connected to a common heat receiving part 10.

[0084] FIG. 11 is a plan view of the boiling cooling device 1C shown in FIG. 10. In the example shown in FIG. 11, the plurality of heat radiating containers 21 are arranged in a staggered pattern in a plan view. Note that the arrangement of the heat radiating containers 21 is not limited to the staggered arrangement, and may be other regular arrangements such as a matrix arrangement, or an irregular arrangement. Also, the number of the heat radiating containers 21 is not limited to the number shown in the example shown in FIG. 11 and is arbitrary. Further, the volumes of the plurality of condensation chambers S20 are equal to each other, but may be different from each other.

[0085] In the second modification, the heat receiving part 10 has one container forming the accommodation chamber S10, but may have a plurality of containers forming the accommodation chamber S10. The container may be provided for each heat radiating container 21.

[0086] The present invention has been described based on the preferred embodiments as above, but the present invention is not limited to the foregoing embodiments. Any configurations of the foregoing embodiments may be combined with each other. Further, the configuration of each part of the present invention can be replaced with any configuration that exhibits the same function as that of the foregoing embodiments, and any configuration can be added.

Explanation of Reference Numerals

[0087] 1…Boiling cooling device, 10…Heating part, 11…Bottom plate, 12…Top plate, 13…Side wall, 20…Heat radiating part, 21…Heat radiating container, 22…Heat radiating fins, 30…Heat transport part, 31…First pipe part, 32…Second pipe part, 211…Bottom plate, 212…Top plate, 213…Cylindrical part, 301…First opening, 302…Second opening, 303…Third opening, 304…Fourth opening, 305…Fifth opening, 306…Sixth opening, 307…Seventh opening, 310…First inner wall surface, 320…Second inner wall surface, A…Vertical line, A0…Center line, A1…Center line, A2…Center line, F0…Liquid film, G0…Horizontal plane, O1…Center, O2…Center, O3…Center, O4…Center, O5…Center, RE…Refrigerant, RE0…Liquid level, S1…First flow path, S10…Containment chamber, S2…Second flow path, S20…Condensation chamber, θ…Inclination angle.

Claims

1. A heat receiving part that contains a refrigerant and receives heat from a heating element, A heat radiating part that has a heat radiating container arranged obliquely with respect to the vertical line and radiates heat from the heat receiving part, A first pipe part having a first flow path that transports the vapor-phase refrigerant generated by vaporizing the refrigerant in the heat receiving part to the heat radiating part, A second pipe part having a second flow path that transports the liquid-phase refrigerant generated by condensing the vapor-phase refrigerant in the heat radiating part to the heat receiving part, and is provided with, The center line of each of the first flow path and the second flow path extends linearly, The first pipe part has a first opening that opens toward the heat receiving part and a second opening that opens toward the heat radiating part, The second pipe part has a third opening that opens toward the heat receiving part and a fourth opening that opens toward the heat radiating part, The center of the first opening is located above the center of the third opening, The center of the second opening is located above the center of the fourth opening, A part of the first pipe part is located in the heat radiating container, A boiling cooling device.

2. The center line of the first flow path is located above the center line of the second flow path, The boiling cooling device according to claim 1.

3. The cross-sectional area of the first flow path is larger than the cross-sectional area of the second flow path, The boiling cooling device according to claim 1 or 2.

4. The first pipe part further has a fifth opening located in the heat radiating container, Each of the second opening and the fifth opening opens to the side of the first pipe part, The boiling cooling device according to any one of claims 1 to 3.

5. The second opening faces downward, The boiling cooling device according to claim 4.

6. The fifth opening faces upward, The boiling cooling device according to claim 5.

7. The fifth opening is located below the second opening, The opening area of the fifth opening is larger than the opening area of the second opening, The boiling cooling device according to any one of claims 4 to 6.

8. The heat radiating part further has heat radiating fins that are thermally connected to the heat radiating container, The heat radiating fins are inclined with respect to the vertical line, The boiling cooling device according to any one of claims 1 to 7.

9. A cooling method for a heating element using a boiling cooling device, the boiling cooling device including: a heat receiving portion that contains a refrigerant and receives heat from the heating element; a heat radiating portion that has a heat radiating container and radiates heat received from the heat receiving portion; a first pipe portion that has a first flow path for transporting a vapor-phase refrigerant generated by vaporizing the refrigerant in the heat receiving portion to the heat radiating portion; and a second pipe portion that has a second flow path for transporting a liquid-phase refrigerant generated by condensing the vapor-phase refrigerant in the heat radiating portion to the heat receiving portion. The center line of the first flow path and the center line of the second flow path each extend linearly. The first pipe portion has a first opening that opens toward the heat receiving portion and a second opening that opens toward the heat radiating portion. The second pipe portion has a third opening that opens toward the heat receiving portion and a fourth opening that opens toward the heat radiating portion. Arranging the heat radiating container to be inclined with respect to a horizontal plane. Positioning the center of the first opening above the center of the third opening and positioning the center of the second opening above the center of the fourth opening. A cooling method for a heating element.

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