Cooling device

Abstract

To provide a cooling device having excellent cooling characteristics while reducing the pressure loss of gas-phase primary refrigerant sealed in a container by preventing the occurrence of bridges in liquid-phase primary refrigerant.SOLUTION: A cooling device includes a container to the outer face of which at least one electrical heating element is thermally connected, a primary refrigerant sealed in the container, and a plurality of condenser tubes penetrating through a gas phase part in the container for secondary refrigerant to be distributed therein. An area of at least part of the outer face of the condenser tube having a site which is not dipped in the primary refrigerant is arranged with a distance L of 1.0 mm or longer away from the outer face of another adjacent condenser tube.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a cooling device for cooling electric / electronic components and the like, and more particularly to a cooling device that has excellent refrigerant flow characteristics and thereby excellent cooling characteristics for heat-generating bodies such as electric / electronic components. [Background technology]

[0002] As electronic devices become more sophisticated, they are increasingly equipped with a high density of heat-generating elements such as electric and electronic components, and the amount of heat generated by these elements is also increasing. If the temperature of these elements rises above a predetermined allowable temperature, it can cause the components to malfunction, so it is important to maintain the temperature of these elements below the allowable temperature. Therefore, cooling devices for cooling the electric and electronic components are installed inside electronic devices.

[0003] On the other hand, as mentioned above, heat-generating elements such as electric and electronic components are densely packed, which limits the space available for installing a cooling device. Therefore, there is a demand for cooling devices with improved cooling performance while avoiding enlargement. To address this issue, a cooling device has been proposed in which heat-generating elements such as electronic components are immersed in a liquid-phase primary refrigerant stored inside a container. The liquid-phase primary refrigerant receives heat from the heat-generating elements and changes phase from liquid to gas, rising inside the container. The gas-phase primary refrigerant changes phase to liquid on the outer surface of the condenser tube due to the heat exchange action of a condenser tube through which a secondary refrigerant flows, and the liquid-phase primary refrigerant drips from the outer surface of the condenser tube and circulates back into the liquid-phase primary refrigerant in which the heat-generating elements are immersed, thereby maintaining the temperature of the heat-generating elements below an allowable temperature (Patent Document 1).

[0004] In Patent Document 1, heat from the heating element is transferred to a secondary refrigerant via a primary refrigerant in which the heating element is immersed, and is then released to the external environment via a condenser tube through which the secondary refrigerant flows. In Patent Document 1, condensation fins and a wick structure are provided on the outer surface of the condenser tube. The primary refrigerant changes to a liquid phase due to the heat exchange action between the outer surface of the condenser tube and the condensation fins, and drips from the wick structure into the liquid primary refrigerant in which the heating element is immersed, causing the primary refrigerant to circulate.

[0005] In Patent Document 1, the condensation tubes and condensation fins are arranged at a high density in order to improve the heat exchange effect of the outer surfaces of the condensation tubes and the condensation fins. However, there is a problem in that the surface tension of the liquid primary refrigerant can cause bridges of the liquid primary refrigerant to form between adjacent condensation tubes and between adjacent condensation fins, particularly in the areas below in the direction of gravity.

[0006] When a bridge of the liquid-phase primary refrigerant occurs between adjacent condenser tubes and between adjacent condensing fins, the gas-phase primary refrigerant is prevented from smoothly diffusing inside the container. As described above, in Patent Document 1, the pressure loss of the gas-phase primary refrigerant is large, which prevents the gas-phase primary refrigerant from circulating smoothly, resulting in an insufficient cooling performance of the cooling device. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] US Patent Application Publication No. 2013 / 0105122 Summary of the Invention [Problem to be solved by the invention]

[0008] In view of the above circumstances, an object of the present invention is to provide a cooling device having excellent cooling characteristics by preventing the formation of a bridge of a liquid-phase primary refrigerant, thereby reducing pressure loss of a gas-phase primary refrigerant sealed inside a container. [Means for solving the problem]

[0009] The gist of the configuration of the cooling device of the present invention is as follows. [1] A container having at least one heating element thermally connected to an exterior surface thereof; a primary refrigerant sealed inside the container; a plurality of condensation pipes penetrating a gas phase portion inside the container and through which a secondary refrigerant flows; A cooling device in which at least a partial area of ​​the outer surface of at least one of the condenser tubes having a portion that is not immersed in the primary refrigerant is arranged with a distance L of 1.0 mm or more from the outer surface of another adjacent condenser tube. [2] The cooling device described in [1], wherein the portions of the outer surface of the condenser tube that are not immersed in the primary refrigerant are arranged at a distance L of 1.0 mm or more from the portions of the outer surface of the adjacent condenser tubes that are not immersed in the primary refrigerant. [3] The cooling device according to [1] or [2], wherein the distance L is a distance in a direction perpendicular to the extension direction of the condensation tube inside the container. [4] The cooling device according to [1] or [2], wherein the distance L is 1.0 mm or more and 5.0 mm or less. [5] The cooling device according to [1] or [2], wherein the radial shape of the condenser tube is a flat shape having a flat portion. [6] The cooling device according to [5], wherein the distance L is the distance between the flat portion of the condenser tube and the flat portion of another adjacent condenser tube. [7] The cooling device according to [5], wherein the distance L is the distance between a portion of the condenser tube other than the flat portion and a portion of another adjacent condenser tube other than the flat portion. [8] A cooling device according to [1] or [2], wherein the condenser tubes are arranged in a plurality in the direction of gravity. [9] A cooling device according to [1] or [2], further comprising a container inner surface area increasing portion on the inner surface of the container that increases the contact area with the liquid phase primary refrigerant.

[10] A cooling device according to [9], wherein the container inner surface area increasing portion is a plate-like fin, a pin fin and / or a depression.

[11] A cooling device according to [9], wherein a wick portion having capillary force is formed in at least a portion of the container inner surface area increasing portion.

[12] A cooling device as described in [1] or [2], wherein the heating element is thermally connected to a portion of the outer surface of the container where the liquid phase primary refrigerant is present or in the vicinity of a portion where the liquid phase primary refrigerant is present.

[13] A cooling device according to [1] or [2], wherein the outer surface of the condenser tube is formed with a condenser tube outer surface area increasing portion that increases the contact area with the gas phase primary refrigerant.

[14] A cooling device according to [1] or [2], wherein the inner surface of the condenser tube is formed with a condenser tube inner surface area increasing portion that increases the contact area with the secondary refrigerant.

[0010] In the cooling device described above, the primary refrigerant sealed inside the container changes phase from liquid to gas when it receives heat from a heating element. The primary refrigerant then changes phase from gas to liquid on the outer surface of the condenser tube due to heat exchange through the condenser tube, which penetrates the gas phase of the container and through which the secondary refrigerant flows. During this phase change, latent heat released from the primary refrigerant is transferred to the secondary refrigerant flowing through the condenser tube. The secondary refrigerant, having received latent heat from the primary refrigerant, flows through the condenser tube from the inside to the outside of the cooling device, transporting the latent heat to the outside of the cooling device. Furthermore, the primary refrigerant that changes phase from gas to liquid on the outer surface of the condenser tube returns from the gas phase to the downward direction of gravity, primarily due to gravity. As described above, the primary refrigerant repeatedly changes phase from liquid to gas and back to liquid within the interior space of the container. [Effects of the Invention]

[0011] Conventionally, the cooling performance of a cooling device has been improved by increasing the number of condenser tubes installed inside a container as much as possible to improve the heat exchange function of the condenser tubes. In contrast, in the cooling device of the present invention, adjacent condenser tubes are spaced apart from each other by a distance L of 1.0 mm or more between their outer surfaces. This reduces the number of condenser tubes installed inside the container, thereby suppressing the heat exchange function of the condenser tubes. However, the inventors have discovered that even if the number of condenser tubes installed inside the container is reduced, preventing the formation of bridges of the liquid-phase primary refrigerant between adjacent condenser tubes is important for improving the cooling performance.

[0012] That is, in this aspect of the cooling device of the present invention, among the condenser tubes having a portion not immersed in the primary refrigerant, at least a partial region of the outer surface of at least one condenser tube is arranged with a distance L of 1.0 mm or more from the outer surface of an adjacent condenser tube, thereby preventing the primary refrigerant that has changed phase from gas to liquid on the outer surface of the condenser tube from forming a bridge between the adjacent condenser tube and the other condenser tube due to its surface tension, particularly in the portion below in the direction of gravity. Therefore, this aspect of the cooling device of the present invention reduces the pressure loss of the gas-phase primary refrigerant sealed inside the container and facilitates the flow of the gas-phase primary refrigerant, resulting in reduced thermal resistance and excellent cooling characteristics.

[0013] Furthermore, according to an embodiment of the cooling device of the present invention, the portions of the outer surfaces of the condensing tubes that are not immersed in the primary refrigerant are spaced a distance L of 1.0 mm or more from the portions of the adjacent condensing tubes that are not immersed in the primary refrigerant, thereby more reliably preventing the primary refrigerant that has changed to a liquid phase on the outer surfaces of the condensing tubes from forming a bridge between the adjacent condensing tubes.

[0014] Furthermore, according to an aspect of the cooling device of the present invention, the distance L is a distance perpendicular to the direction in which the condenser tubes extend inside the container, thereby more reliably preventing the primary refrigerant that has changed into a liquid phase on the outer surface of a condenser tube from forming a bridge with another adjacent condenser tube.

[0015] In addition, in this aspect of the cooling device of the present invention, the distance L is 1.0 mm or more and 5.0 mm or less, which prevents the primary refrigerant that has changed to a liquid phase on the outer surfaces of the condenser tubes from forming a bridge between the condenser tubes and adjacent condenser tubes, while minimizing the need to reduce the number of condenser tubes installed inside the container. Therefore, this aspect of the cooling device of the present invention allows the condenser tubes to exhibit excellent heat exchange performance while smoothing the flow of the gas-phase primary refrigerant.

[0016] Furthermore, according to an aspect of the cooling device of the present invention, the radial shape of the condenser tube is a flat shape having a flat portion, so that even if the interior of the container is a small space, many condenser tubes can be arranged, thereby further improving the cooling characteristics of the cooling device.

[0017] Furthermore, according to an aspect of the cooling device of the present invention, the inner surface of the container is further provided with a container inner surface surface area increasing portion that increases the contact area with the primary refrigerant in liquid phase, thereby facilitating heat transfer from the heating element to the primary refrigerant via the container, thereby enabling the cooling device to exhibit excellent cooling characteristics.

[0018] In addition, according to an aspect of the cooling device of the present invention, a wick portion having capillary force is formed in at least a portion of the container inner surface increased surface area portion, and the capillary force of the wick portion promotes the reflux of the liquid phase stored inside the container from the container inner surface increased surface area portion to the primary refrigerant, thereby further improving the reflux characteristics of the primary refrigerant.

[0019] Furthermore, in accordance with an embodiment of the present invention, the condenser tubes are provided with increased surface area portions on their outer surfaces that increase the contact area with the gaseous primary refrigerant, thereby improving the heat exchange effect of the condenser tubes and accelerating the phase change of the primary refrigerant from gaseous to liquid phase. This further accelerates heat transfer from the primary refrigerant to the secondary refrigerant, thereby further improving the cooling characteristics of the chiller.

[0020] Furthermore, according to an aspect of the cooling device of the present invention, the condenser tube has an inner surface area increasing portion formed on the inner surface thereof, which increases the contact area with the secondary refrigerant. This improves the heat exchange function of the condenser tube, thereby further accelerating heat transfer from the primary refrigerant to the secondary refrigerant. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a perspective view illustrating an outline of a cooling device according to a first embodiment of the present invention. [Figure 2] 1 is a front cross-sectional view illustrating an outline of a cooling device according to a first embodiment of the present invention. [Figure 3] 2 is an explanatory diagram showing an enlarged view of the outer surface of a condenser pipe provided in the cooling device according to the first embodiment of the present invention. FIG. [Figure 4] 3 is an explanatory diagram showing an enlarged view of the inner surface of a condenser pipe provided in the cooling device according to the first embodiment of the present invention. FIG. [Figure 5] FIG. 10 is a front cross-sectional view illustrating an outline of a cooling device according to a second embodiment of the present invention. [Figure 6] FIG. 10 is a front cross-sectional view illustrating an outline of a cooling device according to a third embodiment of the present invention. [Figure 7] FIG. 10 is a front cross-sectional view illustrating an outline of a cooling device according to a fourth embodiment of the present invention. [Figure 8] FIG. 10 is a front cross-sectional view illustrating an outline of a cooling device according to a fifth embodiment of the present invention. [Figure 9] FIG. 10 is a front cross-sectional view illustrating an outline of a cooling device according to a sixth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0022] First, a cooling device according to a first embodiment of the present invention will be described. FIG. 1 is a perspective view illustrating an outline of the cooling device according to the first embodiment of the present invention. FIG. 2 is a front cross-sectional view illustrating an outline of the cooling device according to the first embodiment of the present invention. FIG. 3 is an explanatory enlarged view of the outer surface of a condenser pipe provided in the cooling device according to the first embodiment of the present invention. FIG. 4 is an explanatory enlarged view of the inner surface of a condenser pipe provided in the cooling device according to the first embodiment of the present invention.

[0023] 1 and 2, a cooling device 1 according to a first embodiment of the present invention includes a container 10, a primary refrigerant 20 sealed inside the container 10, and a condenser pipe 40 penetrating a gas phase portion 11 inside the container 10 and through which a secondary refrigerant 30 flows. A heating element 100 to be cooled is thermally connected to an outer surface 12 of the container 10, thereby cooling the heating element 100.

[0024] A hollow cavity 13 is formed inside the container 10. The cavity 13 is a space sealed from the external environment and is depressurized by a degassing process. The shape of the container 10 is not particularly limited, but in the cooling device 1, it is a low rectangular parallelepiped.

[0025] 1 and 2, a predetermined amount of liquid-phase primary refrigerant 20 is stored in cavity 13. The liquid-phase primary refrigerant 20 is stored in a volume that allows a gas phase portion 11 to be formed inside container 10. The liquid-phase primary refrigerant 20 stored in cavity 13 of container 10 is present on the lower side of cavity 13 in the direction of gravity, and a gas phase portion 11 in which no liquid-phase primary refrigerant 20 is stored is formed on the upper side of cavity 13 in the direction of gravity.

[0026] The connection position of the heating element 100 is not particularly limited, but in the cooling device 1, the heating element 100 is thermally connected to a portion of the outer surface 12 of the container 10 where the liquid phase primary refrigerant 20 is present or near the portion where the liquid phase primary refrigerant 20 is present, specifically, to the bottom surface 16 of the container 10. By connecting the heating element 100 to the container 10 at the above-mentioned portion, heat transfer from the heating element 100 to the liquid phase primary refrigerant 20 stored in the hollow portion 13 of the container 10 is facilitated, and the thermal resistance from the heating element 100 to the primary refrigerant 20 can be reduced.

[0027] The condenser tube 40 is a tubular member, and the secondary refrigerant 30 flows through the internal space of the condenser tube 40. The condenser tube 40 has a portion that penetrates the gas phase portion 11 inside the container 10. The internal space of the condenser tube 40 does not communicate with the interior of the container 10 (hollow portion 13). In other words, the internal space of the condenser tube 40 does not communicate with the gas phase portion 11 and is a space independent from the gas phase portion 11. Inside the container 10, a plurality of condenser tubes 40, 40, 40... are arranged in parallel at predetermined intervals. Furthermore, inside the container 10, the plurality of condenser tubes 40, 40, 40... extend in a direction approximately perpendicular to the direction of gravity.

[0028] The plurality of condenser tubes 40, 40, 40... include a plurality of first condenser tubes 40-1, 40-1, 40-1... located above in the direction of gravity, and a plurality of second condenser tubes 40-2, 40-2, 40-2... located below in the direction of gravity relative to the first condenser tube 40-1. As described above, in the cooling device 1, a plurality of condenser tubes 40 are arranged in the direction of gravity.

[0029] The plurality of first condenser pipes 40-1, 40-1, 40-1... are arranged in parallel to one another on approximately the same plane inside container 10, and the plurality of second condenser pipes 40-2, 40-2, 40-2... are arranged in parallel to one another on approximately the same plane inside container 10. Furthermore, as will be described later, cooling device 1 is provided with container inner surface area increased section 50 which serves as an evaporator, and the plurality of first condenser pipes 40-1, 40-1, 40-1... are located in areas which overlap with container inner surface area increased section 50 in a plan view, and the plurality of second condenser pipes 40-2, 40-2, 40-2... are located in areas which do not overlap with container inner surface area increased section 50 in a plan view.

[0030] Of the multiple condenser tubes 40, 40, 40..., the first condenser tube 40-1 is not in contact with the liquid-phase primary refrigerant 20 stored on the lower side in the direction of gravity (i.e., the liquid-phase primary refrigerant 20 stored in the hollow portion 13 of the container 10). In other words, the liquid-phase primary refrigerant 20 stored in the hollow portion 13 of the container 10 is not in contact with the first condenser tube 40-1. From the above, the entire outer surface 41 of the first condenser tube 40-1, including the end portion on the lower side in the direction of gravity, is not immersed in the liquid-phase primary refrigerant 20.

[0031] On the other hand, in the cooling device 1, of the multiple condenser tubes 40, 40, 40..., the second condenser tube 40-2 is in contact with the liquid-phase primary refrigerant 20 stored in the cavity 13 of the container 10. In the cooling device 1, the lower side of the second condenser tube 40-2 in the direction of gravity is in contact with the liquid-phase primary refrigerant 20 stored in the cavity 13 of the container 10, and the upper side of the second condenser tube 40-2 in the direction of gravity is not in contact with the liquid-phase primary refrigerant 20 stored in the cavity 13 of the container 10. From the above, the lower side of the outer surface 41 of the second condenser tube 40-2 in the direction of gravity is immersed in the liquid-phase primary refrigerant 20, and the upper side in the direction of gravity is not immersed in the liquid-phase primary refrigerant 20.

[0032] 1 and 2, in the cooling device 1, of the condenser tubes 40 having a portion that is not immersed in the liquid-phase primary refrigerant 20, at least a partial region of the outer surface 41 of at least one condenser tube 40 is disposed with a distance L of 1.0 mm or more from the outer surface 41 of an adjacent condenser tube 40. In the cooling device 1, at least a partial region of the outer surface 41 of a first condenser tube 40-1 that overlaps with the container inner surface area increased portion 50 in a plan view is disposed with a distance L of 1.0 mm or more from the outer surface 41 of an adjacent first condenser tube 40-1. In the cooling device 1, the first condenser tube 40-1 is disposed in parallel inside the container 10 with the entire outer surface 41 of the adjacent first condenser tube 40-1 being spaced apart by a distance L of 1.0 mm or more. Therefore, in the first condenser tube 40-1, the portion of the outer surface 41 of the first condenser tube 40-1 that is not immersed in the liquid phase primary refrigerant 20 is arranged at a distance L of 1.0 mm or more from the portion of the outer surface 41 of another adjacent first condenser tube 40-1 that is not immersed in the liquid phase primary refrigerant 20.

[0033] As described above, outer surface 41 of first condenser tube 40-1 is disposed opposite outer surface 41 of another adjacent first condenser tube 40-1 with a gap therebetween, distance L being 1.0 mm or more.

[0034] In the cooling device 1, the distance L between the outer surfaces 41 of adjacent first condenser tubes 40-1 is a distance in a direction approximately perpendicular to the extension direction of the first condenser tubes 40-1 inside the container 10 and is also a distance in a direction approximately perpendicular to the direction of gravity. In the cooling device 1, the outer surfaces 41 of adjacent first condenser tubes 40-1 are arranged with a distance L of 1.0 mm or more between them, and therefore, the primary refrigerant 20 that has changed phase from gas to liquid on the outer surface 41 of one first condenser tube 40-1 can be prevented from forming a bridge due to surface tension between the outer surfaces 41 of adjacent first condenser tubes 40-1, particularly in a portion lower in the direction of gravity.

[0035] The cross-sectional shape of first condenser pipe 40-1 in the width direction (i.e., radial direction) is not particularly limited, but in cooling device 1, it has a flat shape having flat portions 46 facing each other and end portions 45 connecting both flat portions 46. In cooling device 1, first condenser pipe 40-1 is arranged in a vertically flat state with flat portions 46 extending in the height direction of container 10.

[0036] Furthermore, in the cooling device 1, for ease of explanation, the distance L between the outer surfaces 41 of adjacent first condenser tubes 40-1 is defined as the distance between the flattened portions 46 of one first condenser tube 40-1 and the flattened portions 46 of another adjacent first condenser tube 40-1. That is, the plurality of first condenser tubes 40-1, 40-1, 40-1, ... are arranged in parallel such that the distance L between the flattened portions 46 of the outer surfaces 41 of adjacent first condenser tubes 40-1 is equal to the distance L. From the above, the flattened portions 46 of the outer surfaces 41 of one first condenser tube 40-1 are arranged opposite the flattened portions 46 of the outer surfaces 41 of another adjacent first condenser tube 40-1 with a gap L of 1.0 mm or more between them.

[0037] Note that instead of the positional relationship in which the flat portions 46 of the outer surfaces 41 of adjacent first condenser tubes 40-1 are spaced apart by distance L, the plurality of first condenser tubes 40-1, 40-1, 40-1... may be arranged in parallel such that the flat portions 46 of one first condenser tube 40-1 are spaced apart by distance L from the end portions 45 of adjacent first condenser tubes 40-1. Furthermore, as will be described later, the plurality of first condenser tubes 40-1, 40-1, 40-1... may be arranged in parallel such that the end portions 45 of one first condenser tube 40-1 are spaced apart by distance L from the end portions 45 of adjacent first condenser tubes 40-1.

[0038] 1 and 2, in cooling device 1, second condenser tubes 40-2 are arranged in parallel such that the entire outer surface 41 of each second condenser tube 40-2 is spaced a distance L of 1.0 mm or more from the entire outer surface 41 of an adjacent second condenser tube 40-2. Therefore, in each second condenser tube 40-2, the portion of the outer surface 41 of the second condenser tube 40-2 that is not immersed in liquid-phase primary refrigerant 20 is spaced a distance L of 1.0 mm or more from the portion of the outer surface 41 of the adjacent second condenser tube 40-2 that is not immersed in liquid-phase primary refrigerant 20. Furthermore, the portion of the outer surface 41 of each second condenser tube 40-2 that is immersed in liquid-phase primary refrigerant 20 is spaced a distance L of 1.0 mm or more from the portion of the outer surface 41 of the adjacent second condenser tube 40-2 that is immersed in liquid-phase primary refrigerant 20.

[0039] As described above, outer surface 41 of second condenser tube 40-2 is disposed opposite outer surface 41 of another adjacent second condenser tube 40-2 with a gap therebetween, distance L being 1.0 mm or more.

[0040] In the cooling device 1, the distance L between the outer surfaces 41 of adjacent second condenser tubes 40-2 is a distance in a direction approximately perpendicular to the extension direction of the second condenser tubes 40-2 inside the container 10 and is also a distance in a direction approximately perpendicular to the direction of gravity. In the cooling device 1, the portions of the outer surfaces 41 of adjacent second condenser tubes 40-2 that are not immersed in the liquid-phase primary refrigerant 20 and located on the upper side in the direction of gravity are spaced apart by a distance L of 1.0 mm or more. Therefore, the primary refrigerant 20 that has changed from the gas phase to the liquid phase at the portion of the outer surface 41 of the second condenser tube 40-2 that is not immersed in the liquid-phase primary refrigerant 20 (the portion on the upper side in the direction of gravity) can be prevented from forming a bridge between the portion of the outer surface 41 of the adjacent second condenser tube 40-2 that is not immersed in the liquid-phase primary refrigerant 20 (the portion on the upper side in the direction of gravity) and the portion of the outer surface 41 of the adjacent second condenser tube 40-2 that is not immersed in the liquid-phase primary refrigerant 20 (the portion on the upper side in the direction of gravity) due to its surface tension.

[0041] The cross-sectional shape of second condenser pipe 40-2 in the width direction (i.e., radial direction) is not particularly limited, but in cooling device 1, it has a flat shape having flat portions 46 facing each other and end portions 45 connecting both flat portions 46. In cooling device 1, second condenser pipe 40-2 is arranged in a horizontally flat state with flat portions 46 extending in the width direction of container 10.

[0042] Furthermore, in the cooling device 1, for ease of explanation, the distance L between the outer surfaces 41 of adjacent second condenser tubes 40-2 is the distance in terms of the positional relationship between the end 45 (a portion other than the flattened portion 46) of one second condenser tube 40-2 and the end 45 (a portion other than the flattened portion 46) of another adjacent second condenser tube 40-2. In other words, the multiple second condenser tubes 40-2, 40-2, 40-2... are arranged in parallel in a positional relationship such that the distance L is between the ends 45 of the outer surfaces 41 of adjacent second condenser tubes 40-2. From the above, the end 45 of the outer surface 41 of a second condenser tube 40-2 is arranged opposite the end 45 of the outer surface 41 of an adjacent second condenser tube 40-2 with a gap of 1.0 mm or more between them.

[0043] Note that instead of the positional relationship in which the ends 45 of the outer surfaces 41 of adjacent second condenser tubes 40-2 are spaced apart by distance L, the plurality of second condenser tubes 40-2, 40-2, 40-2... may be arranged in parallel such that the end 45 of one second condenser tube 40-2 is spaced apart by distance L from the flattened portion 46 of another adjacent second condenser tube 40-2. Furthermore, the plurality of second condenser tubes 40-2, 40-2, 40-2... may be arranged in parallel such that the flattened portion 46 of one second condenser tube 40-2 is spaced apart by distance L from the flattened portion 46 of another adjacent second condenser tube 40-2.

[0044] 1 and 2 , cooling device 1 has a portion where first condenser pipe 40-1 and second condenser pipe 40-2 are adjacent to each other, and in the portion where first condenser pipe 40-1 and second condenser pipe 40-2 are adjacent to each other, it is not necessary for them to be arranged in parallel inside container 10 with the entire outer surface 41 of first condenser pipe 40-1 separated from the entire outer surface 41 of the adjacent second condenser pipe 40-2 by a distance L of 1.0 mm or more. In other words, in the portion where first condenser pipe 40-1 and second condenser pipe 40-2 are adjacent to each other, it is acceptable for the outer surface 41 of first condenser pipe 40-1 to be separated from the outer surface 41 of the adjacent second condenser pipe 40-2 by a distance L of 1.0 mm or more inside container 10, or it is not necessary for the distance L to be 1.0 mm or more.

[0045] In cooling device 1, the distance between outer surface 41 of first condenser tube 40-1 and outer surface 41 of adjacent second condenser tube 40-2 is a distance in a direction oblique to the direction of gravity. In cooling device 1, the portion of outer surface 41 of second condenser tube 40-2 that is not immersed in liquid-phase primary refrigerant 20 and located on the upper side in the direction of gravity may be spaced apart from outer surface 41 of adjacent first condenser tube 40-1 by a distance L of 1.0 mm or more, or may not be spaced apart from outer surface 41 of adjacent first condenser tube 40-1 by a distance L of less than 1.0 mm. When the outer surface 41 of the second condenser tube 40-2 is positioned with a distance L of 1.0 mm or more from the outer surface 41 of the adjacent first condenser tube 40-1, the primary refrigerant 20 that has changed phase from gas to liquid at the portion of the outer surface 41 of the second condenser tube 40-2 that is not immersed in the liquid phase primary refrigerant 20 (the portion above in the direction of gravity) can be prevented from forming a bridge between the outer surface 41 of the adjacent first condenser tube 40-1 and the second condenser tube 40-2 due to its surface tension. On the other hand, the primary refrigerant 20 that has changed to liquid phase on the outer surface 41 of the first condenser tube 40-1, which overlaps with the container inner surface area increasing section 50 in a planar view, may have a reduced rate of returning to the container inner surface area increasing section 50. However, when the outer surface 41 of the second condenser tube 40-2 is positioned with a distance of less than 1.0 mm from the outer surface 41 of the adjacent first condenser tube 40-1, the primary refrigerant 20 that has changed to liquid phase on the outer surface 41 of the second condenser tube 40-2 can be smoothly returned to the liquid phase primary refrigerant 20 stored in the hollow section 13. As a result, the liquid phase primary refrigerant 20 can be smoothly returned to the container inner surface area increasing section 50.

[0046] Furthermore, in the cooling device 1, the outer surface 41 of the first condenser tube 40-1 does not need to be spaced a distance L of 1.0 mm or more from a portion of the outer surface 41 of the adjacent second condenser tube 40-2 that is located above in the direction of gravity and that is not immersed in liquid-phase primary refrigerant 20. When the outer surface 41 of the first condenser tube 40-1 is spaced a distance L of 1.0 mm or more from the outer surface 41 of the adjacent second condenser tube 40-2, the primary refrigerant 20 that has changed phase from gas to liquid on the outer surface 41 of the first condenser tube 40-1 can be prevented from forming a bridge due to its surface tension between the portion of the outer surface 41 of the adjacent second condenser tube 40-2 that is not immersed in liquid-phase primary refrigerant 20 that is not immersed in liquid-phase primary refrigerant 20 (the portion above in the direction of gravity). On the other hand, the primary refrigerant 20 that has changed to liquid phase on the outer surface 41 of the first condensing tube 40-1 may flow back at a slower rate to the container inner surface area increased portion 50. However, if the outer surface 41 of the first condensing tube 40-1 is positioned less than 1.0 mm away from the outer surface 41 of the adjacent second condensing tube 40-2, the primary refrigerant 20 that has changed to liquid phase on the outer surface 41 of the second condensing tube 40-2 can flow back smoothly to the liquid phase primary refrigerant 20 stored in the hollow portion 13. As a result, the liquid phase primary refrigerant 20 can be flowed back smoothly to the container inner surface area increased portion 50.

[0047] The distance L between the outer surfaces 41 of adjacent first condenser tubes 40-1 and the distance L between the outer surfaces 41 of adjacent second condenser tubes 40-2 are not particularly limited as long as they are 1.0 mm or more, but is preferably 2.0 mm or more in order to reliably prevent the formation of bridges in the primary refrigerant 20. Furthermore, the distance L is preferably 5.0 mm or less, more preferably 4.0 mm or less, and particularly preferably 3.0 mm or less, in order to prevent a reduction in the number of condenser tubes 40 installed inside the container 10 and to allow the condenser tubes to exhibit excellent heat exchange properties.

[0048] Note that, in the portion of the condenser tube 40 immersed in the liquid-phase primary refrigerant 20, there is no problem of bridging of the primary refrigerant 20, and therefore, in the portion immersed in the liquid-phase primary refrigerant 20, the condenser tube 40 does not need to be arranged so that the distance L is 1.0 mm or more.

[0049] 1 and 2, in the cooling device 1, a container inner surface area increasing portion 50 is formed on the inner surface 15 of the container 10, which increases the contact area with the liquid-phase primary refrigerant 20 stored in the cavity 13 of the container 10. In the cooling device 1, the container inner surface area increasing portion 50, which is a portion that increases the surface area of ​​the inner surface 15 of the container 10, such as unevenness, is formed in a region of the inner surface 15 of the container 10 that corresponds to a portion that is thermally connected to the heating element 100. As described above, the container inner surface area increasing portion 50 functions as an evaporator portion (heat receiving portion) of the cooling device 1. In the cooling device 1, the container inner surface area increasing portion 50 is formed in the center of the bottom surface 16 of the inner surface 15 of the container 10.

[0050] The formation of the container inner surface area increasing portion 50 increases the contact area between the liquid-phase primary refrigerant 20 stored in the cavity 13 of the container 10 and the inner surface 15 of the container 10 in a region of the inner surface 15 of the container 10 that corresponds to the portion thermally connected to the heating element 100. Therefore, the container inner surface area increasing portion 50 facilitates heat transfer from the heating element 100 to the liquid-phase primary refrigerant 20 via the container 10. As a result, the phase change of the primary refrigerant 20 from liquid to gas is promoted, further improving the cooling characteristics of the cooling device 1.

[0051] The container inner surface area increased portion 50, which is an evaporation portion, is immersed in the liquid phase primary refrigerant 20 stored in the cavity 13 of the container 10. Therefore, the container inner surface area increased portion 50 is in direct contact with the liquid phase primary refrigerant 20 stored in the cavity 13 of the container 10. In the cooling device 1, a region 52 below the container inner surface area increased portion 50 in the direction of gravity is immersed in the liquid phase primary refrigerant 20 stored in the cavity 13 of the container 10. On the other hand, a region 51 above the container inner surface area increased portion 50 in the direction of gravity is not immersed in the liquid phase primary refrigerant 20 stored in the cavity 13 of the container 10, but is located in the gas phase portion 11 inside the container 10.

[0052] The container inner surface area increasing portion 50 can be provided, for example, by molding the container 10 using a mold or by attaching a separate member to the inner surface 15 of the container 10. The container inner surface area increasing portion 50 can be provided, for example, by concave and convex portions formed on the inner surface 15 of the container 10. Specific examples of the container inner surface area increasing portion 50 include plate fins or pin fins erected on the bottom surface 16 of the container 10, and depressions formed in the bottom surface 16 of the container 10. Examples of methods for forming the plate fins or pin fins include attaching separately prepared plate fins or pin fins to the bottom surface 16 of the container 10 by soldering, brazing, sintering, or the like, or by cutting, extruding, or etching the bottom surface 16 of the container 10. Examples of methods for forming the depressions include cutting, extruding, or etching the bottom surface 16 of the container 10.

[0053] In the cooling device 1, a plurality of square or rectangular thin plate-like fins 56, 56, 56... are arranged in parallel at predetermined intervals as the container inner surface area increasing portion 50. For ease of explanation, in the cooling device 1, the heights of the plurality of thin plate-like fins 56, 56, 56... are all approximately the same. From the above, in the cooling device 1, the tips 53 in the region 51 above the direction of gravity of the container inner surface area increasing portion 50, i.e., the tips 53 of the plurality of thin plate-like fins 56, 56, 56... are approximately the same height.

[0054] 1 and 2, a plurality of first condenser pipes 40-1, 40-1, 40-1... are arranged above, in the direction of gravity, container inner surface area increasing section 50. In cooling device 1, tips 53 of region 51 above, in the direction of gravity, container inner surface area increasing section 50 are arranged opposite to the plurality of first condenser pipes 40-1, 40-1, 40-1...

[0055] A wick portion 57 having capillary force is formed in at least a partial region of the container inner surface area increased portion 50. In the cooling device 1, the wick portion 57 is provided in at least a partial region of the surface of the container inner surface area increased portion 50, i.e., in at least a partial region of the surface of the thin plate-like fin 56. Specifically, the wick portion 57 is formed at the tip 53 of the container inner surface area increased portion 50. As described above, the wick portion 57 is formed at the tip 53 of the multiple thin plate-like fins 56, 56, 56...

[0056] In the cooling device 1, the wick portion 57 is formed continuously from the tip 53 of the container inner surface area increasing portion 50 to the bottom surface 16 of the container 10. At the tip 53 of the container inner surface area increasing portion 50, the wick portion 57 is not in contact with the liquid phase primary refrigerant 20 stored in the cavity 13 of the container 10. A region 52 below the wick portion 57 in the direction of gravity is immersed in the liquid phase primary refrigerant 20 stored in the cavity 13 of the container 10, while a region 51 above the wick portion 57 in the direction of gravity is not immersed in the liquid phase primary refrigerant 20 stored in the cavity 13 of the container 10, and is located in the gas phase portion 11 inside the container 10.

[0057] The primary refrigerant 20 that has changed from a gas phase to a liquid phase on the outer surface 41 of the condenser tube 40 (first condenser tube 40-1) flows back from the outer surface 41 of the condenser tube 40 (first condenser tube 40-1) to the container inner surface increased surface area portion 50, which is an evaporation portion. At this time, the wick portion 57 promotes the return of the primary refrigerant 20 that has changed from a gas phase to a liquid phase on the outer surface 41 of the condenser tube 40 (first condenser tube 40-1) from the outer surface 41 of the condenser tube 40 (first condenser tube 40-1) to the container inner surface increased surface area portion 50 by the action of capillary force.

[0058] Furthermore, the primary refrigerant 20 that has returned from the outer surface 41 of the condenser tube 40 (first condenser tube 40-1) to the container inner surface increased surface area section 50 returns from the container inner surface increased surface area section 50 to the liquid-phase primary refrigerant 20 stored in the cavity 13 of the container 10. At this time, the wick section 57, by the action of capillary force, promotes the return of the primary refrigerant 20 that has changed to the liquid phase from the container inner surface increased surface area section 50 to the liquid-phase primary refrigerant 20 stored in the cavity 13 of the container 10. This further improves the return characteristics of the liquid-phase primary refrigerant 20.

[0059] Examples of the structure of the wick portion 57 include a sintered metal body, a metal mesh, a metal braid, an edging portion, etc. Examples of the sintered metal body include a sintered metal powder such as copper powder, a sintered metal fiber, a sintered metal mesh, and a sintered metal braid.

[0060] The material of the thin plate-like fins 56 is not particularly limited, and may be, for example, a thermally conductive material. Specific examples of the material of the thin plate-like fins 56 include metal members (for example, copper, copper alloy, aluminum, aluminum alloy, stainless steel, etc.).

[0061] The material of the container 10 is not particularly limited and may be, for example, copper, copper alloy, aluminum, aluminum alloy, nickel, nickel alloy, stainless steel, titanium, titanium alloy, etc. The material of the condenser tube 40 is not particularly limited and may be, for example, copper, copper alloy, aluminum, aluminum alloy, nickel, nickel alloy, stainless steel, titanium, titanium alloy, etc. The primary refrigerant 20 is not particularly limited and may be, for example, an electrically insulating refrigerant. Specific examples include water, fluorocarbons, cyclopentane, ethylene glycol, and mixtures thereof. The secondary refrigerant is not particularly limited and may be, for example, water, antifreeze (main component of which is, for example, ethylene glycol), etc.

[0062] On the other hand, the primary refrigerant 20 that has changed phase from gas to liquid on the outer surface 41 of the second condensing pipe 40-2 on the upper side in the direction of gravity flows downward in the direction of gravity along the outer surface 41 of the second condensing pipe 40-2 due to the action of gravity, and returns to the liquid-phase primary refrigerant 20 stored in the hollow portion 13 of the container 10.

[0063] 3, the outer surfaces 41 of the condenser tubes 40 may be provided with increased surface area portions 43, such as irregularities, on the outer surfaces 41 of the condenser tubes 40, thereby increasing the surface area of ​​the condenser tubes 40 and increasing the contact area with the gaseous primary refrigerant. The increased surface area portions 43 on the outer surfaces 41 of the condenser tubes 40 improve the heat exchange performance of the condenser tubes 40 and accelerate the phase change of the primary refrigerant from the gaseous phase to the liquid phase. This further accelerates heat transfer from the gaseous primary refrigerant to the secondary refrigerant 30, further improving the cooling characteristics of the cooling device 1. The increased surface area portions 43 may be formed on the entire outer surfaces 41 that come into contact with the gaseous primary refrigerant, or may be formed only on a partial region of the outer surfaces 41 (for example, the downward side of the outer surfaces 41 in the direction of gravity that faces the liquid primary refrigerant 20 stored in the container 10).

[0064] The condenser tube outer surface area increasing portion 43 can be provided, for example, by molding the condenser tube 40 using a mold or by attaching a member separate from the condenser tube 40 to the outer surface 41 of the condenser tube 40. The form of the condenser tube outer surface area increasing portion 43 is not particularly limited, and examples thereof include a plurality of protrusions formed on the outer surface 41 of the condenser tube 40, a plurality of grooves or depressions formed on the outer surface 41 of the condenser tube 40, etc.

[0065] The method for forming the protrusions that constitute the condenser tube outer surface area increased portion 43 is not particularly limited, and examples thereof include methods of attaching separately prepared protrusions to the outer surface 41 of the condenser tube 40 by soldering, brazing, sintering, etc. Furthermore, the method for forming the recesses and grooves that constitute the condenser tube outer surface area increased portion 43 is not particularly limited, and examples thereof include methods of cutting or etching the outer surface 41 of the condenser tube 40.

[0066] In the condenser tube outer surface area increased portion 43 shown in FIG. 3, conical protrusions 47 are arranged in a staggered pattern on the outer surface 41. More specifically, in the condenser tube outer surface area increased portion 43 shown in FIG. 5, the protrusions 47 are shaped like square pyramids. In the condenser tube outer surface area increased portion 43, a plurality of protrusions 47 are arranged linearly in parallel in the longitudinal direction of the condenser tube 40 to form a protrusion row 48, and a plurality of protrusion rows 48 are also arranged in parallel along the circumferential direction of the condenser tube 40. In addition, the positions of the protrusions 47 in adjacent protrusion rows 48 are offset by a predetermined amount, so that the protrusions 47 are arranged in a staggered pattern. The condenser tube outer surface area increased portion 43 described above reduces the surface tension of the outer surface 41 of the condenser tube 40, further accelerating the phase change of the primary refrigerant from the gas phase to the liquid phase.

[0067] The protrusions 47 of the condenser tube outer surface area increasing portion 43 may be formed by rolling, forging, cutting, or etching the outer surface 41. In the above-described method, the condenser tube outer surface area increasing portion 43 is integral with the condenser tube 40. By forming the condenser tube outer surface area increasing portion 43 by rolling, forging, cutting, or etching the outer surface 41 of the condenser tube 40, the condenser tube 40 can be made smaller and more space-saving than in a configuration in which separately manufactured protrusions are attached to the outer surface 41 of the condenser tube 40, thereby enabling the cooling device 1 to be made smaller and more space-saving. Furthermore, by making the condenser tube 40 smaller and more space-saving, more protrusions 47 can be provided per unit area of ​​the outer surface 41 of the condenser tube 40, thereby further accelerating the phase change of the primary refrigerant from the gas phase to the liquid phase.

[0068] 4, the cooling device 1 may have an inner surface 42 of the condenser tube 40 formed with an increased surface area portion 44, such as an uneven surface, to increase the surface area of ​​the inner surface 42 of the condenser tube 40 and thereby increase the contact area between the inner surface 42 of the condenser tube 40 and the secondary refrigerant 30. The formation of the increased surface area portion 44 improves the heat exchange function of the condenser tube 40, further facilitating heat transfer from the gaseous primary refrigerant to the secondary refrigerant 30.

[0069] The condenser tube inner surface area increasing portion 44 can be provided, for example, by molding the condenser tube 40 using a mold or by attaching a member separate from the condenser tube 40 to the inner surface 42 of the condenser tube 40. The form of the condenser tube inner surface area increasing portion 44 is not particularly limited, and examples thereof include a plurality of protrusions formed on the inner surface 42 of the condenser tube 40, a plurality of grooves or depressions formed on the inner surface 42 of the condenser tube 40, etc.

[0070] Examples of methods for forming the protrusions that constitute the condenser tube inner surface area increased portion 44 include attaching separately manufactured protrusions to the inner surface 42 of the condenser tube 40 by soldering, brazing, sintering, etc., or cutting or etching the inner surface 42 of the condenser tube 40. Examples of methods for forming the recesses and grooves include cutting or etching the inner surface 42 of the condenser tube 40. In the condenser tube inner surface area increased portion 44 of FIG. 6, multiple grooves are formed spirally on the inner surface 42.

[0071] Next, the operation of the cooling device 1 according to the first embodiment will be described.

[0072] When the liquid-phase primary refrigerant 20 stored in the cavity 13 of the container 10 receives heat from the heating element 100, the liquid-phase primary refrigerant 20 changes phase from liquid to gas and absorbs the heat from the heating element 100 as latent heat. The primary refrigerant that has changed phase to gas moves upward in the direction of gravity within the internal space of the container 10 and flows into the gas phase section 11 of the container 10. Meanwhile, low-temperature secondary refrigerant 30 flows through the condenser tubes 40 (first condenser tube 40-1 and second condenser tube 40-2) that penetrate the gas phase section 11. With the low-temperature secondary refrigerant 30 flowing through the condenser tubes 40, the condenser tubes 40 arranged in the gas phase section 11 exhibit a heat exchange effect. When the primary refrigerant that has changed phase to gas comes into contact with or close to the outer surface 41 of the condenser tube 40, it releases latent heat due to the heat exchange effect of the condenser tube 40 and changes phase from gas to liquid at the outer surface of the condenser tube 40. The latent heat released when the primary refrigerant changes phase from gas phase to liquid phase is transferred to the secondary refrigerant 30 flowing through the condenser tube 40 .

[0073] Of the multiple condenser tubes 40, 40, 40..., the primary refrigerant 20 that has changed phase from gas to liquid on the outer surface 41 of the first condenser tube 40-1 returns from the outer surface 41 of the first condenser tube 40-1 to the container inner surface increased surface area section 50, which is the evaporation section, as described above. The liquid-phase primary refrigerant 20 that has returned from the outer surface 41 of the first condenser tube 40-1 to the container inner surface increased surface area section 50 further returns from the container inner surface increased surface area section 50 to the liquid-phase primary refrigerant 20 stored in the cavity 13 of the container 10. Furthermore, the primary refrigerant 20 that has changed phase from gas to liquid on the outer surface 41 of the second condenser tube 40-2 among the multiple condenser tubes 40, 40, 40... is in contact with the liquid-phase primary refrigerant 20 stored in the hollow portion 13 of the container 10 on the downward side in the direction of gravity of the second condenser tube 40-2, and therefore flows downward in the direction of gravity along the outer surface of the second condenser tube 40-2 due to the action of gravity, as described above, and thereby returns to the liquid-phase primary refrigerant 20 stored in the hollow portion 13 of the container 10. From the above, the primary refrigerant 20 repeatedly changes phase from liquid to gas and from gas to liquid in the internal space of the container 10.

[0074] The secondary refrigerant 30, which has received heat from the gas-phase primary refrigerant, circulates from the inside to the outside of the cooling device 1 along the extension direction of the condensation pipe 40, thereby transporting the heat of the heating element 100 to the outside of the cooling device 1.

[0075] In the cooling device 1, among the condenser tubes 40 having a portion not immersed in the liquid-phase primary refrigerant 20, at least a partial region of the outer surface 41 of at least one condenser tube is disposed with a distance L of 1.0 mm or more from the outer surface 41 of an adjacent condenser tube 40, so that the primary refrigerant 20 that has changed phase from gas to liquid on the outer surface 41 of the condenser tube 40 can be prevented from forming a bridge between the adjacent condenser tube 40 due to surface tension, particularly in the portion below in the direction of gravity. Therefore, in the cooling device 1, the pressure loss of the gas-phase primary refrigerant sealed inside the container 10 is reduced, and the flow of the gas-phase primary refrigerant is smoothed, resulting in reduced thermal resistance and excellent cooling characteristics.

[0076] Furthermore, in the cooling device 1, the outer surfaces 41 of adjacent condenser tubes 40 are spaced apart by a distance L of 1.0 mm or more, which reduces the number of condenser tubes 40 installed inside the container 10. Therefore, when multiple condenser tubes 40, 40, 40, ... are connected in series inside the container 10, it is possible to reduce the pressure loss of the secondary refrigerant 30 flowing through the condenser tubes 40. Therefore, in the cooling device 1, it is possible to reduce the power consumption required to circulate the secondary refrigerant 30 through the condenser tubes 40.

[0077] Furthermore, in the cooling device 1, the portions of the outer surface 41 of the condenser tubes 40 that are not immersed in the primary refrigerant 20 are arranged at a distance L of 1.0 mm or more from the portions of the adjacent condenser tubes 40 that are not immersed in the primary refrigerant 20, which further reliably prevents the primary refrigerant 20 that has changed into a liquid phase on the outer surface 41 of the condenser tube 40 from forming a bridge with the outer surface 41 of the adjacent condenser tube 40.

[0078] Furthermore, in the cooling device 1, the above-mentioned distance L is a distance perpendicular to the extension direction of the condenser tubes 40 inside the container 10, and is also a distance approximately perpendicular to the direction of gravity, so that it is possible to more reliably prevent the primary refrigerant 20 that has changed into a liquid phase on the outer surface 41 of the condenser tube 40 from forming a bridge with the outer surface 41 of another adjacent condenser tube 40.

[0079] Furthermore, in the cooling device 1, the radial shape of the condenser tubes 40 is a flat shape having flat portions 46, so that even if the interior of the container 10 is a small space, many condenser tubes 40 can be arranged, further improving the cooling characteristics of the cooling device 1.

[0080] Next, a cooling device according to a second embodiment of the present invention will be described. Note that the cooling device according to the second embodiment has the same main components as the cooling device according to the first embodiment, and therefore the same components as those in the cooling device according to the first embodiment will be described using the same reference numerals. Note that Fig. 5 is a front cross-sectional view illustrating the outline of the cooling device according to the second embodiment of the present invention.

[0081] In the cooling device 1 according to the first embodiment, a plurality of condenser tubes 40 are arranged in the direction of gravity, and the plurality of second condenser tubes 40-2, 40-2, 40-2... are positioned lower in the direction of gravity than the plurality of first condenser tubes 40-1, 40-1, 40-1.... However, as shown in Fig. 5, in the cooling device 2 according to the second embodiment, the plurality of second condenser tubes 40-2, 40-2, 40-2... are arranged at approximately the same position in the direction of gravity as the plurality of first condenser tubes 40-1, 40-1, 40-1.... In other words, the plurality of second condenser tubes 40-2, 40-2, 40-2... are arranged at approximately the same height as the plurality of first condenser tubes 40-1, 40-1, 40-1....

[0082] As described above, in the cooling device of the present invention, the relationship between the height of first condenser pipe 40-1 and the height of second condenser pipe 40-2 can be selected as appropriate.

[0083] Furthermore, in the cooling device 1 according to the first embodiment, the second condenser pipes 40-2 are arranged in a horizontally flat state with the flat portions 46 extending in the width direction of the container 10, and the plurality of second condenser pipes 40-2, 40-2, 40-2... are arranged in parallel in a positional relationship where the distance between the ends 45 of adjacent second condenser pipes 40-2 is L. Instead, as shown in Fig. 5 , in the cooling device 2, like the first condenser pipe 40-1, the second condenser pipes 40-2 are arranged in a vertically flat state with the flat portions 46 extending in the height direction of the container 10, and the plurality of second condenser pipes 40-2, 40-2, 40-2... are arranged in parallel in a positional relationship where the distance between the flat portions 46 of adjacent second condenser pipes 40-2 is L.

[0084] In the cooling device 2, at least a partial region of at least one of the outer surfaces 41 of the condenser tubes 40 having a portion not immersed in the liquid-phase primary refrigerant 20 is disposed at a distance L of 1.0 mm or more from the outer surface 41 of an adjacent condenser tube 40, so that the primary refrigerant 20 that has changed phase from gas to liquid on the outer surface 41 of the condenser tube 40 can be prevented from forming a bridge between the adjacent condenser tube 40 due to surface tension, particularly in the portion below in the direction of gravity. Therefore, in the cooling device 2, the pressure loss of the gas-phase primary refrigerant sealed inside the container 10 is reduced, and the flow of the gas-phase primary refrigerant is smoothed, resulting in reduced thermal resistance and excellent cooling characteristics.

[0085] Next, a cooling device according to a third embodiment of the present invention will be described. Note that the cooling device according to the third embodiment has the same main components as the cooling devices according to the first and second embodiments, and therefore the same components as those of the cooling devices according to the first and second embodiments will be described using the same reference numerals. Note that Fig. 6 is a front cross-sectional view illustrating the outline of the cooling device according to the third embodiment of the present invention.

[0086] In the cooling devices 1 and 2 according to the first and second embodiments, at least a partial area of ​​the outer surface 41 of a condenser tube 40 having a portion not immersed in the liquid-phase primary refrigerant 20 is disposed with a distance L of 1.0 mm or more from the outer surface 41 of an adjacent condenser tube 40. However, as shown in Fig. 6, in the cooling device 3 according to the third embodiment, the distance L is even larger than that of the cooling devices 1 and 2 according to the first and second embodiments. In the cooling device 3, at least a partial area of ​​the outer surface 41 of a condenser tube 40 having a portion not immersed in the liquid-phase primary refrigerant 20 is disposed with a distance L of 3.0 mm or more from the outer surface 41 of an adjacent condenser tube 40.

[0087] In cooling device 3, first condenser pipe 40-1 is arranged in parallel with the entire outer surface 41 of another adjacent first condenser pipe 40-1, with a distance L of 3.0 mm or more between them. Furthermore, second condenser pipe 40-2 is arranged in parallel with the entire outer surface 41 of another adjacent second condenser pipe 40-2, with a distance L of 3.0 mm or more between them. Furthermore, first condenser pipe 40-1 is arranged in parallel with the entire outer surface 41 of another adjacent second condenser pipe 40-2, with a distance L of 3.0 mm or more between them. In cooling device 3, both first condenser pipe 40-1 and second condenser pipe 40-2 are arranged in a vertically flat state, with flat portions 46 extending in the height direction of container 10.

[0088] In the cooling device 3, the primary refrigerant 20 that has changed phase from gas to liquid on the outer surfaces 41 of the condenser tubes 40 (the first condenser tube 40-1 and the second condenser tube 40-2) can more reliably prevent the formation of bridges of the liquid-phase primary refrigerant 20 between the outer surfaces 41 of adjacent condenser tubes 40 due to its surface tension, particularly in the portion on the lower side in the direction of gravity.

[0089] Next, a cooling device according to a fourth embodiment of the present invention will be described. Note that the cooling device according to the fourth embodiment has the same main components as the cooling devices according to the first to third embodiments, and therefore the same components as those of the cooling devices according to the first to third embodiments will be described using the same reference numerals. Note that Fig. 7 is a front cross-sectional view illustrating the outline of the cooling device according to the fourth embodiment of the present invention.

[0090] In the cooling device 1 according to the first embodiment, the first condenser pipes 40-1 are arranged in a vertically flat state with the flat portions 46 extending in the height direction of the container 10, and the plurality of first condenser pipes 40-1, 40-1, 40-1... are arranged in parallel with each other in a positional relationship in which the distance between the flat portions 46 of adjacent first condenser pipes 40-1 is L. Instead, as shown in Fig. 7 , in the cooling device 4 according to the fourth embodiment, the first condenser pipes 40-1 are arranged in a state in which the flat portions 46 extend in a direction oblique to the height direction and width direction of the container 10, and the plurality of first condenser pipes 40-1, 40-1, 40-1... are arranged in parallel with each other in a positional relationship in which the distance between the boundary portion 49 of the flat portion 46 and the end portion 45 is L.

[0091] As described above, boundary portion 49 of first condenser tube 40-1 is disposed opposite boundary portion 49 of another adjacent first condenser tube 40-1 via a gap having a distance L of 1.0 mm or more. As described above, in the cooling device of the present invention, the extension direction of the flat portion of condenser tube 40, which has a flat shape, can be selected as appropriate.

[0092] In the cooling device 4, at least a partial region of at least one of the outer surfaces 41 of the condenser tubes 40 having a portion not immersed in the liquid-phase primary refrigerant 20 is disposed at a distance L of 1.0 mm or more from the outer surface 41 of an adjacent condenser tube 40, so that the primary refrigerant 20 that has changed phase from gas to liquid on the outer surface 41 of the condenser tube 40 can be prevented from forming a bridge between the adjacent condenser tube 40 due to surface tension, particularly in the portion below in the direction of gravity. Therefore, in the cooling device 4, the pressure loss of the gas-phase primary refrigerant sealed inside the container 10 is reduced, and the flow of the gas-phase primary refrigerant is smoothed, resulting in reduced thermal resistance and excellent cooling characteristics.

[0093] Next, a cooling device according to a fifth embodiment of the present invention will be described. Note that the cooling device according to the fifth embodiment has the same main components as the cooling devices according to the first to fourth embodiments, and therefore the same components as those of the cooling devices according to the first to fourth embodiments will be described using the same reference numerals. Note that Fig. 8 is a front cross-sectional view illustrating the outline of the cooling device according to the fifth embodiment of the present invention.

[0094] In the cooling system 1 according to the first embodiment, the first condenser pipes 40-1 are arranged in a vertically flat state with the flat portions 46 extending in the height direction of the container 10, and the plurality of first condenser pipes 40-1, 40-1, 40-1... are arranged in parallel in a positional relationship where the distance between the flat portions 46 of adjacent first condenser pipes 40-1 is L. Instead, as shown in Fig. 8 , in the cooling system 5 according to the fifth embodiment, the plurality of first condenser pipes 40-1, 40-1, 40-1... are arranged in parallel in a positional relationship where the distance between the end 45 of one first condenser pipe 40-1 and the end 45 of another adjacent first condenser pipe 40-1 is L.

[0095] As described above, in cooling device 5, first condenser pipe 40-1 and second condenser pipe 40-2 are both arranged in a horizontally flat state with flat portions 46 extending in the width direction of container 10.

[0096] In the cooling device 5, at least a partial region of at least one of the outer surfaces 41 of the condenser tubes 40 having a portion not immersed in the liquid-phase primary refrigerant 20 is disposed at a distance L of 1.0 mm or more from the outer surface 41 of an adjacent condenser tube 40, so that the primary refrigerant 20 that has changed phase from gas to liquid on the outer surface 41 of the condenser tube 40 can be prevented from forming a bridge between the adjacent condenser tube 40 due to surface tension, particularly in the portion below in the direction of gravity. Therefore, in the cooling device 5, the pressure loss of the gas-phase primary refrigerant sealed inside the container 10 is reduced, and the flow of the gas-phase primary refrigerant is smoothed, resulting in reduced thermal resistance and excellent cooling characteristics.

[0097] Next, a cooling device according to a sixth embodiment of the present invention will be described. Note that the cooling device according to the sixth embodiment has the same main components as the cooling devices according to the first to fifth embodiments, and therefore the same components as those of the cooling devices according to the first to fifth embodiments will be described using the same reference numerals. Note that Fig. 9 is a front cross-sectional view illustrating the outline of the cooling device according to the sixth embodiment of the present invention.

[0098] In the cooling device 1 according to the first embodiment, the multiple first condensation pipes 40-1, 40-1, 40-1... were arranged parallel to one another on approximately the same plane inside the container 10. However, instead, as shown in FIG. 9, in the cooling device 6 according to the sixth embodiment, the multiple first condensation pipes 40-1, 40-1, 40-1... are arranged in the direction of gravity.

[0099] The cooling device 6 has a plurality of first condensation tubes 40-1, 40-1, 40-1..., including a plurality of first condensation tubes 40-11, 40-11, 40-11... located on the lower side in the direction of gravity, and a plurality of first condensation tubes 40-12, 40-12, 40-12... located on the upper side in the direction of gravity.

[0100] The plurality of first condenser tubes 40-11, 40-11, 40-11... located on the lower side in the direction of gravity are arranged in parallel to one another on approximately the same plane. The first condenser tubes 40-11 are arranged in a vertically flat state with their flat portions 46 extending in the height direction of the container 10, and the plurality of first condenser tubes 40-11, 40-11, 40-11... are arranged in parallel to one another in a positional relationship such that the distance L is between the flat portions 46 of adjacent first condenser tubes 40-11.

[0101] The plurality of first condenser tubes 40-12, 40-12, 40-12... located on the upper side in the direction of gravity are arranged in parallel to one another on approximately the same plane. The first condenser tubes 40-12 are arranged in a vertically flat state with flat portions 46 extending in the height direction of the container 10, and the plurality of first condenser tubes 40-12, 40-12, 40-12... are arranged in parallel in a positional relationship such that the distance L is between the flat portions 46 of adjacent first condenser tubes 40-12.

[0102] In addition, the multiple first condenser tubes 40-11, 40-11, 40-11... and the multiple first condenser tubes 40-12, 40-12, 40-12... are arranged in a staggered pattern, and the distance L is between the boundary portion 49 of the first condenser tube 40-11 and the boundary portion 49 of the adjacent first condenser tube 40-12 on the upper side in the direction of gravity.

[0103] As described above, in the cooling device of the present invention, the number of condenser pipes 40 arranged in the direction of gravity can be selected as appropriate.

[0104] In the cooling device 6, at least a partial region of at least one of the outer surfaces 41 of the condenser tubes 40 having a portion not immersed in the liquid-phase primary refrigerant 20 is disposed at a distance L of 1.0 mm or more from the outer surface 41 of an adjacent condenser tube 40, so that the primary refrigerant 20 that has changed phase from gas to liquid on the outer surface 41 of the condenser tube 40 can be prevented from forming a bridge between the adjacent condenser tube 40 due to surface tension, particularly in the portion below in the direction of gravity. Therefore, in the cooling device 6, the pressure loss of the gas-phase primary refrigerant sealed inside the container 10 is reduced, and the flow of the gas-phase primary refrigerant is smoothed, resulting in reduced thermal resistance and excellent cooling characteristics.

[0105] Next, a cooling device according to another embodiment of the present invention will be described. In the cooling device according to each of the above embodiments, the condenser tube has a flat cross-sectional shape in the radial direction, but the cross-sectional shape is not particularly limited and may be, for example, a circular shape. [Industrial Applicability]

[0106] The cooling device of the present invention can reduce thermal resistance by facilitating the flow of gaseous primary refrigerant, and therefore can be used in a wide range of fields, and is highly useful, for example, in cooling electronic components that generate a large amount of heat and are mounted on circuit boards, such as central processing units (CPUs). [Explanation of symbols]

[0107] 1, 2, 3, 4, 5, 6 Cooling device 10 containers 11 Gas phase section 20 Primary refrigerant 30 Secondary Refrigerant 40 Condenser tube 41 Exterior

Claims

1. a container having at least one heating element thermally connected to an exterior surface thereof; a primary refrigerant sealed inside the container; a plurality of condensation pipes penetrating a gas phase portion inside the container and through which a secondary refrigerant flows; at least one of the condensing tubes having a portion not immersed in the primary refrigerant has an outer surface at least partially spaced from an outer surface of another adjacent condensing tube by a distance L of 1.0 mm or more; The container further includes an inner surface area increasing portion on the inner surface of the container that increases a contact area with the primary refrigerant in a liquid phase, the plurality of condensing tubes include a plurality of first condensing tubes that do not come into contact with the primary refrigerant in a liquid phase stored on a lower side in a direction of gravity inside the container, and a plurality of second condensing tubes that come into contact with the primary refrigerant in a liquid phase stored on a lower side in a direction of gravity inside the container, on the lower side in the direction of gravity, but do not come into contact with the primary refrigerant in a liquid phase on an upper side in the direction of gravity, an upper region of the container inner surface increased surface area portion in the direction of gravity is not immersed in the primary refrigerant in a liquid phase stored in the lower side of the container in the direction of gravity, and is located in the gas phase portion; a cooling device in which the first condenser pipe is positioned so as to overlap the container inner surface increased surface area portion when viewed from above in the direction of gravity, and the second condenser pipe is positioned so as not to overlap the container inner surface increased surface area portion when viewed from above in the direction of gravity.

2. 2. The cooling device according to claim 1, wherein a portion of the outer surface of each condenser tube that is not immersed in the primary refrigerant is disposed with a distance L of 1.0 mm or more between adjacent portions of the outer surface of each condenser tube that are not immersed in the primary refrigerant.

3. 3. The cooling device according to claim 1, wherein the distance L is a distance in a direction perpendicular to the direction in which the condenser tube extends inside the container.

4. 3. The cooling device according to claim 1, wherein the distance L is equal to or greater than 1.0 mm and equal to or less than 5.0 mm.

5. 3. The cooling device according to claim 1, wherein the condenser tube has a flattened shape in the radial direction, the flattened shape having a flat portion.

6. The cooling device according to claim 5 , wherein the distance L is a distance between the flat portion of the condenser tube and the flat portion of another adjacent condenser tube.

7. The cooling device according to claim 5 , wherein the distance L is a distance between a portion of the condenser tube other than the flat portion and another portion of an adjacent condenser tube other than the flat portion.

8. The cooling device according to claim 1 or 2, wherein a plurality of the condenser tubes are arranged in the direction of gravity.

9. 3. The cooling device according to claim 1, wherein the surface area increasing portion of the container inner surface is a plate-like fin, a pin fin, and / or a depression.

10. 3. The cooling device according to claim 1, wherein a wick portion having capillary force is formed in at least a partial region of the container inner surface area increasing portion.

11. 3. The cooling device according to claim 1, wherein the heating element is thermally connected to a portion of the outer surface of the container where the liquid phase primary refrigerant is present or near a portion where the liquid phase primary refrigerant is present.

12. 3. The cooling device according to claim 1, wherein the condenser tube has an outer surface area increasing portion formed on the outer surface thereof for increasing the contact area with the primary refrigerant in a gas phase.

13. 3. The cooling device according to claim 1, wherein the condenser tube has an inner surface formed with an increased surface area portion for increasing the contact area with the secondary refrigerant.

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