Cooling device

Abstract

To provide a cooling device that can reduce an amount of a refrigerant used.SOLUTION: A cooling device includes: a storage tank that stores a first refrigerant in a liquid phase below a heating element; a refrigerant supply unit that pumps up the first refrigerant in the storage tank and supplies the first refrigerant to the heating element; and a refrigerant cooling unit that cools the first refrigerant by exchanging heat between the first refrigerant and the second refrigerant by supplying a second refrigerant that has a lower temperature than the first refrigerant, wherein the storage tank collects the first refrigerant supplied to the heating element.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses a cooling system that directly cools an electronic device having a heating element by immersing it in a liquid-phase refrigerant. The cooling system has a cooling tank filled with a refrigerant. The electronic device is immersed in the refrigerant in the cooling tank.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the cooling system described in Patent Document 1, it is necessary to immerse the entire electronic device in the refrigerant in the cooling tank. Therefore, this cooling system requires a large amount of refrigerant. Since the refrigerant is expensive, it is required to reduce the amount of refrigerant used.

[0005] The present disclosure has been made to solve the above problems, and an object thereof is to provide a cooling device capable of reducing the amount of refrigerant used.

Means for Solving the Problems

[0006] To solve the above problems, a cooling device according to the present disclosure includes a storage tank that stores a liquid-phase first refrigerant below a heating element, a refrigerant supply unit that pumps up the first refrigerant in the storage tank and supplies the first refrigerant to the heating element, and a refrigerant cooling unit that cools the first refrigerant by performing heat exchange between the first refrigerant and a second refrigerant that is supplied at a temperature lower than the first refrigerant. A fin that is thermally connected to the aforementioned heating element,The storage tank is equipped with a storage tank that recovers the first refrigerant supplied to the heating element. The refrigerant supply unit injects the first refrigerant toward the heating element, the refrigerant supply unit causes the first refrigerant to collide with the fins, the refrigerant supply unit injects the first refrigerant so that it spreads radially as it approaches the heating element, and the fins extend along the direction of the injection of the first refrigerant. . [Effects of the Invention]

[0007] The cooling device of this disclosure can reduce the amount of refrigerant used. [Brief explanation of the drawing]

[0008] [Figure 1] This is a perspective view showing the configuration of a cooling device according to the first embodiment of this disclosure. [Figure 2] This is a side view showing the configuration of a cooling device according to the first embodiment of this disclosure. [Figure 3] This is a perspective view showing the configuration of a cooling device according to a second embodiment of this disclosure. [Figure 4] This is a cross-sectional view of a cooling tube according to a second embodiment of the present disclosure. [Figure 5] This is a side view of a fin relating to a first modified example of the second embodiment of the present disclosure. [Figure 6] This is a perspective view showing the configuration of a cooling device according to a second modified example of the second embodiment of the present disclosure. [Modes for carrying out the invention]

[0009] <First Embodiment> Hereinafter, the cooling device 10 according to the first embodiment of this disclosure will be described with reference to Figures 1 and 2. The cooling device 10 is used to cool electronic equipment that performs high-speed calculations. As shown in Figure 1, in this embodiment, the cooling device 10 is used for a server 1 installed in a data center.

[0010] Server 1 has a printed circuit board on which components such as a CPU and a GPU are installed. Because the CPU and GPU are components responsible for high-speed computation, they are subjected to heavy loads. Therefore, the CPU and GPU generate more heat than other parts of Server 1.

[0011] Hereinafter, the printed circuit board of server 1 may be simply referred to as "substrate 2", and the elements that generate heat particularly at high temperatures in substrate 2 such as the CPU and GPU may be referred to as "heating elements 3".

[0012] Substrate 2 is formed in a rectangular plate shape. A heating element 3 is provided on the surface of substrate 2. Substrate 2 is arranged so as to extend in the vertical direction.

[0013] (Configuration of the cooling device) Subsequently, the configuration of the cooling device 10 will be described. As shown in FIGS. 1 and 2, the cooling device 10 includes a storage tank 20, a refrigerant supply unit 30, a refrigerant cooling unit 40, and fins 11.

[0014] (Storage tank) The storage tank 20 is arranged below the substrate 2. The storage tank 20 is a rectangular parallelepiped box-shaped container. The storage tank 20 is open upward. The storage tank 20 stores the liquid-phase first refrigerant R1 below the heating element 3. The first refrigerant R1 is an insulating refrigerant. Examples of the first refrigerant R1 include liquids based on fluorocarbons, etc. The first refrigerant R1 is supplied to the heating element 3 by the refrigerant supply unit 30 described later. The heating element 3 is cooled by exchanging heat with the first refrigerant R1. The storage tank 20 recovers the first refrigerant R1 supplied to the heating element 3.

[0015] (Refrigerant supply unit) The refrigerant supply unit 30 pumps up the first refrigerant R1 in the storage tank 20 and supplies the first refrigerant R1 to the heating element 3. The refrigerant supply unit 30 of the present embodiment flows the first refrigerant R1 downward on the substrate 2 and forms a liquid film M of the first refrigerant R1 in the region including the heating element 3 on the substrate 2. The refrigerant supply unit 30 has a circulation pipe 31, a pump 32, and a header pipe 33.

[0016] (Circulation pipe) The circulation pipe 31 is provided outside the storage tank 20. One end 31a of the circulation pipe 31 is connected to the bottom 21 of the storage tank 20. The circulation pipe 31 communicates with the inside of the storage tank 20. The circulation pipe 31 extends upward from the bottom 21 of the storage tank 20. The other end 31b of the circulation pipe 31 is located above the substrate 2. The first refrigerant R1 flows through the circulation pipe 31.

[0017] (Pump) The pump 32 is provided in the circulation pipe 31. In the present embodiment, the pump 32 is provided below the bottom 21 of the storage tank 20. The pump 32 pumps the first refrigerant R1 and causes the first refrigerant R1 to flow from one end 31a to the other end 31b of the circulation pipe 31.

[0018] (Header pipe) The header pipe 33 is provided at the other end 31b of the circulation pipe 31. The header pipe 33 communicates with the circulation pipe 31. The header pipe 33 is arranged directly above the substrate 2. The header pipe 33 is along the upper edge of the substrate 2. A plurality of supply holes 34 are provided in the header pipe 33. The plurality of supply holes 34 are arranged in a row at equal intervals. Each supply hole 34 opens downward. The first refrigerant R1 supplied from the circulation pipe 31 flows through the header pipe 33.

[0019] (Refrigerant cooling part) The refrigerant cooling part 40 supplies a second refrigerant R2 that is cooler than the first refrigerant R1, performs heat exchange between the first refrigerant R1 and the second refrigerant R2, and cools the first refrigerant R1. In the present embodiment, the refrigerant cooling part 40 supplies the second refrigerant R2 to the liquid film M of the first refrigerant R1 formed on the substrate 2.

[0020] In the present embodiment, the refrigerant cooling part 40 is installed at a position facing the heating element 3 on the substrate 2. The location where the heating element 3 is provided on the substrate 2 has a higher heat generation density than other locations on the substrate 2. That is, the refrigerant cooling part 40 supplies the second refrigerant R2 to the region on the substrate 2 where the heat generation density is high.

[0021] In this embodiment, the refrigerant cooling unit 40 is a cooling fan 41, and the second refrigerant R2 is air R21. The cooling fan 41 cools the first refrigerant R1 by directly supplying air R21 to the liquid film M of the first refrigerant R1 formed on the substrate 2. The cooling fan 41 also directly supplies air R21 to the heat-generating element 3 in a spot manner.

[0022] (fin) The fins 11 are provided in the region on the substrate 2 where a liquid film M of the first refrigerant R1 is formed. Multiple fins 11 are provided on the heating element 3 in this embodiment. The fins 11 are formed in a pin shape that extends perpendicularly from the heating element 3 to the surface of the substrate 2. Multiple fins 11 are arranged regularly in the vertical and horizontal directions. When viewed from the direction normal to the surface of the substrate 2, the multiple fins 11 are arranged in a zigzag pattern in each row in the vertical and horizontal directions, alternating between each other.

[0023] (Circulation of the first refrigerant) Next, we will explain the circulation of the first refrigerant R1 within the cooling device 10. First, the first refrigerant R1 stored at the bottom 21 of the storage tank 20 flows into the circulation pipe 31. The first refrigerant R1 that has flowed into the circulation pipe 31 is pumped by the pump 32 from one end 31a to the other end 31b of the circulation pipe 31. After that, the first refrigerant R1 is supplied to the header pipe 33. The first refrigerant R1 flows out downward from the supply hole 34 of the header pipe 33.

[0024] The first refrigerant R1 that flows out from the supply hole 34 is supplied to the upper edge of the substrate 2. The first refrigerant R1 flows from the upper edge to the lower edge of the substrate 2 due to its own gravity. At this time, a liquid film M of the first refrigerant R1 is formed on the substrate 2. The first refrigerant R1 flows in the state of liquid film M. Therefore, the first refrigerant R1 flows more slowly on the substrate 2 compared to the circulation piping 31 and the header pipe 33. Also, the flow velocity of the first refrigerant R1 is constant on the substrate 2.

[0025] The first refrigerant R1 flowing over the substrate 2 exchanges heat with the heating element 3 and the substrate 2. As a result, the heating element 3 and the substrate 2 are cooled, and the first refrigerant R1 is heated.

[0026] The liquid film M of the first refrigerant R1 formed on the substrate 2 is supplied with the second refrigerant R2 from the refrigerant cooling unit 40. The first refrigerant R1 exchanges heat with the second refrigerant R2. As a result, the first refrigerant R1 is cooled. In this embodiment, the refrigerant cooling unit 40 is a cooling fan 41, which directly supplies air R21 to the liquid film M of the first refrigerant R1.

[0027] Furthermore, the air R21 supplied by the cooling fan 41 exchanges heat with both the heat-generating element 3 and the substrate 2. This further cools the heat-generating element 3 and the substrate 2.

[0028] When the first refrigerant R1 reaches the lower edge of the substrate 2, it flows down from the substrate 2 towards the storage tank 20. The first refrigerant R1 is stored in the storage tank 20 in a liquid phase. After that, the first refrigerant R1 flows back into the circulation piping 31. In this way, the first refrigerant R1 circulates within the cooling device 10.

[0029] (Effects and Benefits) The cooling device 10 of this embodiment provides the following effects and benefits. In this embodiment, the cooling device 10 comprises a storage tank 20, a refrigerant supply unit 30, and a refrigerant cooling unit 40. The storage tank 20 stores liquid-phase first refrigerant R1 below the heating element 3. The refrigerant supply unit 30 pumps up the first refrigerant R1 from the storage tank 20 and supplies it to the heating element 3. The refrigerant cooling unit 40 cools the first refrigerant R1 by supplying a second refrigerant R2, which is at a lower temperature than the first refrigerant R1, thereby performing heat exchange between the first refrigerant R1 and the second refrigerant R2. Furthermore, the storage tank 20 recovers the first refrigerant R1 supplied to the heating element 3.

[0030] As a result, the first refrigerant R1 supplied to the heating element 3 moves downward due to its own weight and returns to the storage tank 20. The first refrigerant R1 that has returned to the storage tank 20 is supplied again to the heating element 3 by the refrigerant supply unit 30. Therefore, the storage tank 20 only needs to be able to temporarily store the first refrigerant R1 before it is supplied to the heating element 3. Thus, the cooling device 10 does not need to fill the storage tank 20 with the first refrigerant R1 to the extent that the heating element 3 can be immersed in it. Consequently, the cooling device 10 of this embodiment can reduce the amount of first refrigerant R1 used.

[0031] In this embodiment, the heating element 3 is provided on a substrate 2 that extends vertically above the storage tank 20. The refrigerant supply unit 30 flows the first refrigerant R1 downward onto the substrate 2, forming a liquid film M of the first refrigerant R1 in the region of the substrate 2 that includes the heating element 3.

[0032] As a result, the cooling device 10 can flow the first refrigerant R1 at a constant speed. Therefore, the cooling device 10 can suppress the occurrence of stagnant areas of the first refrigerant R1 on the substrate 2. Consequently, the first refrigerant R1 can flow uniformly over the substrate 2. As a result, the cooling device 10 can uniformly cool the entire substrate 2 and the heat-generating element 3 installed on the substrate 2.

[0033] In this embodiment, the refrigerant cooling unit 40 supplies the second refrigerant R2 to the liquid film M of the first refrigerant R1 formed on the substrate 2.

[0034] As a result, the refrigerant cooling unit 40 can directly cool the liquid film M of the first refrigerant R1. Therefore, the cooling device 10 can efficiently cool the first refrigerant R1. Consequently, the amount of first refrigerant R1 required by the cooling device 10 is further reduced.

[0035] In this embodiment, the refrigerant cooling unit 40 supplies a second refrigerant R2 to a region on the substrate 2, such as the heating element 3, where the heat generation density is high.

[0036] As a result, the cooling device 10 can cool the areas on the substrate 2, including the heat-generating element 3, that have a high heat density, using both the first refrigerant R1 and the second refrigerant R2. Therefore, the cooling efficiency of the cooling device 10 can be improved.

[0037] Furthermore, in this embodiment, the cooling device 10 is provided with fins 11 in the region on the substrate 2 where a liquid film M of the first refrigerant R1 is formed.

[0038] As a result, the cooling device 10 can control the thickness of the liquid film M of the first refrigerant R1 by passing the fins 11 over the liquid film M of the first refrigerant R1. For example, by installing the fins 11 near areas of the substrate 2 with high heat density, such as where the heat-generating element 3 is installed, the thickness of the liquid film M of the first refrigerant R1 can be increased in these areas of the substrate 2. Therefore, the cooling device 10 can concentrate the cooling of areas of the substrate 2 with high heat density. In addition, the fins 11 increase the contact area between the substrate 2 and the first refrigerant R1. That is, the heat transfer area between the substrate 2 and the first refrigerant R1 is increased. Therefore, the cooling device 10 can cool the substrate 2 efficiently.

[0039] In the first embodiment described above, the case in which the first refrigerant R1 is in the liquid phase and cools the heating element 3 and the substrate 2 was explained, but the invention is not limited to this. For example, the first refrigerant R1 may partially evaporate on the substrate 2. In this case, the cooling device 10 can cool the region on the substrate 2 including the heating element 3 by utilizing the latent heat of vaporization when the first refrigerant R1 evaporates.

[0040] In the first embodiment described above, the fins 11 were formed in a pin shape, but this is not the only way. The fins 11 may be formed in a plate shape, a comb shape, or a block shape. The fins 11 may also be formed in a porous manner. Furthermore, the fins 11 do not have to be provided on the heating element 3. For example, the fins 11 may be provided on the substrate 2 at locations other than the heating element 3. In addition, multiple types of fins 11 with different shapes may be provided on the substrate 2.

[0041] In the first embodiment described above, the refrigerant cooling unit 40 supplied air R21 as the second refrigerant R2 to the first refrigerant R1, but this is not limited to this. For example, the refrigerant supply unit 30 may supply a second refrigerant R2 other than air R21 to prevent deterioration of the first refrigerant R1.

[0042] In the first embodiment described above, the refrigerant cooling unit 40 is a cooling fan 41, and this cooling fan 41 directly supplies air R21 to the first refrigerant R1, but it is not limited to this. The refrigerant cooling unit 40 may be located in the circulation path of the first refrigerant R1 and may cool the first refrigerant R1 with a refrigerant other than a gas.

[0043] In the first embodiment described above, the refrigerant supply unit 30 supplied the first refrigerant R1 to the entire substrate 2 by flowing it from the upper edge of the substrate 2, but this is not limited to this. The refrigerant supply unit 30 may also supply the first refrigerant R1 to a specific area of ​​the substrate 2 that needs to be cooled. Furthermore, the refrigerant supply unit 30 may supply the first refrigerant R1 in an impingement manner, or it may supply the first refrigerant R1 in a spray manner.

[0044] <Second Embodiment> Hereinafter, the cooling device 210 according to the second embodiment of this disclosure will be described with reference to Figures 3 and 4. For configurations similar to those of the first embodiment described above, the same names and reference numerals will be used, and the description will be omitted as appropriate.

[0045] (cooling device) As shown in Figure 3, the cooling device 210 includes a storage tank 220, a relief valve 211, a refrigerant supply unit 230, a refrigerant cooling unit 240, and a fan 212.

[0046] (Storage tank) The storage tank 220 is a rectangular box-shaped container. Unlike the first embodiment, the upper part 222 of the storage tank 220 is closed. The storage tank 220 houses the entire substrate 2 and the heating element 3 inside. In this embodiment, as in the first embodiment, the substrate 2 is arranged vertically so as to extend in the vertical direction. The storage tank 220 also stores the liquid phase and gaseous phase of the first refrigerant R1 inside. The liquid phase of the first refrigerant R1 is stored at the bottom 221 of the storage tank 220. The liquid level of the liquid phase of the first refrigerant R1 stored in the storage tank 220 is located below the heating element 3. The gaseous phase of the first refrigerant R1 is stored at the upper part 222 of the storage tank 220.

[0047] (Relief valve) The relief valve 211 is installed on the upper part 222 of the storage tank 220. The relief valve 211 communicates with the inside of the storage tank 220. The relief valve 211 opens when the internal pressure of the storage tank 220 rises. When the relief valve 211 opens, the internal pressure of the storage tank 220 decreases.

[0048] (Refrigerant supply unit) The refrigerant supply unit 230 is housed inside the storage tank 220. The refrigerant supply unit 230 pumps up the first refrigerant R1 stored at the bottom 221 of the storage tank 220 and injects the first refrigerant R1 toward the heating element 3. The refrigerant supply unit 230 includes a circulation pipe 231, a pump 232, a filter 233, and an injection unit 234.

[0049] (circulation piping) The circulation pipe 231 extends from the bottom 221 to the top 222 within the storage tank 220. One end 231a of the circulation pipe 231 is immersed in the liquid phase first refrigerant R1 stored in the storage tank 220. The other end 231b of the circulation pipe 231 is located in the same vertical position as the heating element 3.

[0050] (pump) Pump 232 is installed in the circulation piping 231. In this embodiment, pump 232 is immersed in the liquid phase first refrigerant R1 stored in the storage tank 220. Pump 232 pumps the first refrigerant R1 in the storage tank 220, circulating the first refrigerant R1 from one end 231a to the other end 231b of the circulation piping 231.

[0051] (filter) The filter 233 is installed in the circulation piping 231. The filter 233 is located on the other end 231b side of the circulation piping 231, relative to the pump 232. The filter 233 is, for example, an activated carbon filter.

[0052] (Injection part) The injection unit 234 is located at the other end 231b of the circulation pipe 231. The injection unit 234 is supplied with the first refrigerant R1 from the circulation pipe 231. The injection unit 234 faces the heating element 3. The injection unit 234 injects the first refrigerant R1 toward the heating element 3. The first refrigerant R1 is injected in a so-called spray-like manner, spreading radially as it approaches the heating element 3.

[0053] (Refrigerant cooling section) The refrigerant cooling unit 240 is provided at the bottom 221 of the storage tank 220. In this embodiment, the refrigerant cooling unit 240 is a cooling tube 241 that penetrates the bottom 221 of the storage tank 220. Multiple cooling tubes 241 are provided at intervals in the vertical and horizontal directions. The multiple cooling tubes 241 extend parallel to each other within the storage tank 220. The cooling tubes 241 also extend in one direction along the horizontal plane and penetrate a pair of opposing side walls of the storage tank 220. The second refrigerant R2 flows through the cooling tubes 241. The cooling tubes 241 exchange heat between the second refrigerant R2 and the liquid phase first refrigerant R1 stored in the storage tank 220, thereby cooling the liquid phase first refrigerant R1.

[0054] Furthermore, as shown in Figure 4, the cooling tube 241 is formed in a rectangular cylindrical shape. Multiple tube fins 242 are provided on the inner circumferential surface of the cooling tube 241. The tube fins 242 are provided at the corners of the inner circumferential surface of the cooling tube 241 in a cross-sectional view perpendicular to the extending direction of the cooling tube 241. Each tube fin 242 is formed to extend linearly toward the center of the cooling tube 241.

[0055] (fan) The fan 212 is located inside the storage tank 220. The fan 212 is positioned in the upper part 222 inside the storage tank 220. The fan 212 is located above the liquid level of the liquid phase first refrigerant R1 stored in the bottom 221 of the storage tank 220. The fan 212 circulates the gas phase first refrigerant R1 inside the storage tank 220.

[0056] (Circulation of the first refrigerant) Next, we will explain the circulation of the first refrigerant R1 within the cooling device 210. First, the first refrigerant R1 stored at the bottom 221 of the storage tank 220 flows into the circulation pipe 231. The first refrigerant R1 that has flowed into the circulation pipe 231 is pumped by the pump 232 from one end 231a to the other end 231b of the circulation pipe 231. After that, the first refrigerant R1 is supplied to the injection unit 234. The injection unit 234 injects the first refrigerant R1 radially toward the heating element 3.

[0057] The first refrigerant R1 exchanges heat with the heat-generating element 3. As a result, the heat-generating element 3 is cooled, and the first refrigerant R1 is heated.

[0058] The first refrigerant R1 flows down from the heating element 3 towards the storage tank 220. The first refrigerant R1 is recovered in the storage tank 220 in a liquid phase. The cooling tube 241 exchanges heat between the first refrigerant R1 and the second refrigerant R2 recovered at the bottom 221 of the storage tank 220, cooling the first refrigerant R1. The cooled first refrigerant R1 flows back into the circulation pipe 231. In this way, the first refrigerant R1 circulates within the cooling device 210.

[0059] Furthermore, as the first refrigerant R1 circulates within the cooling device 210, some of it evaporates. As a result, gaseous first refrigerant R1 is stored in the upper part 222 of the storage tank 220. The gaseous first refrigerant R1 stored in the storage tank 220 has a greater heat content the higher it is located.

[0060] Fan 212 circulates the first refrigerant R1 in the gas phase inside the storage tank 220. As a result, the gaseous first refrigerant R1 at the top 222 of the storage tank 220 comes into contact with the liquid first refrigerant R1, and heat exchange occurs between the gaseous and liquid first refrigerant R1. As a result, a portion of the gaseous first refrigerant R1 condenses and is recovered as liquid first refrigerant R1 at the bottom 221 of the storage tank 220. The first refrigerant R1 recovered at the bottom 221 of the storage tank 220 flows back into the circulation pipe 231.

[0061] (Effects and Benefits) The cooling device 210 of this embodiment provides the following effects. In this embodiment, the refrigerant supply unit 230 injects the first refrigerant R1 toward the heating element 3.

[0062] This allows the cooling device 210 to collide the first refrigerant R1 with the heat-generating element 3. Therefore, the cooling device 210 can perform so-called impingement cooling on the heat-generating element 3. Thus, the cooling efficiency of the cooling device 210 can be improved.

[0063] In this embodiment, the cooling device 210 is equipped with a fan 212 inside the storage tank 220. The fan 212 circulates the gaseous first refrigerant R1 inside the storage tank 220.

[0064] This allows the fan 212 to circulate the gaseous first refrigerant R1 inside the storage tank 220. Therefore, the cooling device 210 can transfer the high-temperature heat accumulated above the storage tank 220 to the liquid phase first refrigerant R1 stored at the bottom 221 of the storage tank 220. As a result, a portion of the gaseous first refrigerant R1 condenses and is recovered as liquid first refrigerant R1 at the bottom 221 of the storage tank 220. In other words, the cooling device 210 can return the first refrigerant R1 that has evaporated back into the liquid phase. Therefore, the cooling efficiency of the cooling device 210 can be further improved.

[0065] Furthermore, in this embodiment, the cooling tube 241 is formed in a rectangular cylindrical shape.

[0066] This allows the cooling tubes 241 to be installed densely within the storage tank 220. Therefore, the cooling efficiency of the cooling device 210 can be further improved.

[0067] Furthermore, in this embodiment, multiple tube fins 242 are provided on the inner circumferential surface of the cooling tube 241.

[0068] This increases the contact area between the cooling tube 241 and the second refrigerant R2. As a result, heat exchange between the first refrigerant R1 and the second refrigerant R2 becomes more efficient. Therefore, the cooling efficiency of the cooling device 210 can be further improved. For this reason, even if the second refrigerant R2 circulating in the cooling tube 241 has low heat transfer efficiency, such as being a gas, the cooling device 210 can sufficiently cool the first refrigerant R1.

[0069] In the second embodiment described above, the tube fins 242 inside the cooling tube 241 are assumed to extend linearly toward the center of the cooling tube 241, but this is not the only possible configuration. The shape of the tube fins 242, such as their thickness and length, can be changed as appropriate. In a cross-sectional view perpendicular to the direction of extension of the cooling tube 241, the tube fins 242 may extend in a curve toward the center of the cooling tube 241, and four adjacent tube fins 242 may be formed in a spiral shape as a whole.

[0070] In the second embodiment described above, the substrate 2 was positioned vertically so as to extend in the vertical direction, but this is not the only configuration. The substrate 2 may also be positioned horizontally so as to extend in the horizontal direction.

[0071] In the second embodiment described above, the cooling device 210 is operated when the first refrigerant R1 in the storage tank 220 is in a gas-liquid two-phase state, but this is not the only option. The cooling device 210 may be operated when the first refrigerant R1 in the storage tank 220 is in a liquid single-phase state.

[0072] (First modified example of the second embodiment) Next, a first modified example of the second embodiment will be described with reference to Figure 5. As shown in Figure 5, in this modified example, fins 213 are provided on the surface of the heating element 3 facing the injection section 234. A heat transfer plate 214 is provided between the fins 213 and the heating element 3. The heat transfer plate 214 is thermally connected to the heating element 3. Functionality may be improved by sealing ammonia or an alcohol-based liquid throughout the entire interior of the heat transfer plate 214. The fins 213 are formed in a pin shape extending from the heat transfer plate 214 toward the injection section 234. The fins 213 are thermally connected to the heating element 3 via the heat transfer plate 214.

[0073] The refrigerant supply unit 230 causes the first refrigerant R1 to collide with the fins 213. The refrigerant supply unit 230 sprays the first refrigerant R1 toward the heating element 3 in a so-called spray manner, so that it spreads radially as it approaches the heating element 3. The fins 213 extend along the direction of the spray of the first refrigerant R1.

[0074] In this modified example, the cooling device 210 includes fins 213 that are thermally connected to the heat-generating element 3. The refrigerant supply unit 230 causes the first refrigerant R1 to collide with the fins 213.

[0075] This increases the contact area between the heat-generating element 3 and the first refrigerant R1. In other words, the heat transfer area between the heat-generating element 3 and the first refrigerant R1 is increased. Therefore, the first refrigerant R1 can exchange heat more effectively with the heat-generating element 3. Thus, the cooling efficiency of the cooling device 210 can be further improved.

[0076] Furthermore, in this modified example, the refrigerant supply unit 230 injects the first refrigerant R1 so that it spreads radially as it approaches the heating element 3, and the fins 213 extend along the injection direction of the first refrigerant R1.

[0077] As a result, the cooling device 210 can suppress the scattering of the first refrigerant R1 sprayed onto the fins 213. Therefore, the cooling efficiency of the cooling device 210 can be further improved.

[0078] (Second modified example of the second embodiment) Next, a second modified example of the second embodiment will be described with reference to Figure 6. As shown in Figure 6, in this modified example, a portion of the circulation piping 231 of the refrigerant supply unit 230, between one end 231a and the other end 231b, is extended outside the storage tank 220. The refrigerant supply unit 230 is provided on this externally extended circulation piping 231.

[0079] The refrigerant cooling unit 240A is located outside the storage tank 220. The refrigerant cooling unit 240A comprises a casing 243, a heat exchanger (not shown), and a propeller fan 244. The casing 243 is formed in the shape of a rectangular plate. The casing 243 is attached to the side wall of the storage tank 220. The heat exchanger of the refrigerant cooling unit 240A is located inside the casing 243. The first refrigerant R1, which is drawn out from the storage tank 220, is supplied to this heat exchanger. The propeller fan 244 blows air into the heat exchanger inside the casing 243. As a result, heat exchange occurs between the air supplied by the propeller fan 244 and the first refrigerant R1, and the first refrigerant R1 is cooled.

[0080] Furthermore, the cooling device 210 is equipped with a pan 245 below the storage tank 220. The pan 245 is a rectangular box-shaped container that extends horizontally. The pan 245 is open at the top. The pan 245 prevents leakage of the first refrigerant R1.

[0081] Furthermore, a configuration in which the refrigerant cooling unit 240A is provided outside the storage tank 220, as shown in this modified example, may also be applied to the first embodiment.

[0082] Although each embodiment of this disclosure has been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments and may include design changes and the like that do not depart from the gist of this disclosure.

[0083] <Note> The cooling devices 10 and 210 described in each embodiment can be understood, for example, as follows.

[0084] (1) The cooling devices 10 and 210 according to the first embodiment include storage tanks 20 and 220 for storing liquid-phase first refrigerant R1 below the heating element 3, refrigerant supply units 30 and 230 for pumping up the first refrigerant R1 from the storage tanks 20 and 220 and supplying the first refrigerant R1 to the heating element 3, and refrigerant cooling units 40, 240 and 240A for cooling the first refrigerant R1 by supplying a second refrigerant R2 which is at a lower temperature than the first refrigerant R1, thereby performing heat exchange between the first refrigerant R1 and the second refrigerant R2, and the storage tanks 20 and 220 recover the first refrigerant R1 supplied to the heating element 3.

[0085] As a result, the first refrigerant R1 supplied to the heating element 3 moves downward due to its own weight and returns to the storage tanks 20 and 220. The first refrigerant R1 that has returned to the storage tanks 20 and 220 is then supplied again to the heating element 3 by the refrigerant supply units 30 and 230. Therefore, the storage tanks 20 and 220 only need to be able to temporarily store the first refrigerant R1 before it is supplied to the heating element 3. Thus, the cooling devices 10 and 210 do not need to fill the storage tanks 20 and 220 with the first refrigerant R1 to the extent that the heating element 3 can be immersed in them.

[0086] (2) The cooling device 10 according to the second embodiment is the cooling device 10 of (1), wherein the heating element 3 is provided on a substrate 2 that extends vertically above the storage tank 20, and the refrigerant supply unit 30 flows the first refrigerant R1 downward on the substrate 2, forming a liquid film M of the first refrigerant R1 in the region of the substrate 2 including the heating element 3.

[0087] This allows the cooling device 10 to flow the first refrigerant R1 at a constant speed.

[0088] (3) The cooling device 10 of the third embodiment is the cooling device 10 of (2), wherein the refrigerant cooling unit 40 may supply the second refrigerant R2 to the liquid film M of the first refrigerant R1 formed on the substrate 2.

[0089] As a result, the refrigerant cooling unit 40 can directly cool the liquid film M of the first refrigerant R1.

[0090] (4) The cooling device 10 of the fourth embodiment is the cooling device 10 of (3), wherein the refrigerant cooling unit 40 may supply the second refrigerant R2 to a region on the substrate 2 where the heat generation density is high.

[0091] As a result, the cooling device 10 can cool the region on the substrate 2 containing the heat-generating element 3 with high heat density using both the first refrigerant R1 and the second refrigerant R2.

[0092] (5) The cooling device 10 of the fifth embodiment is any of the cooling devices 10 of (2) to (4), wherein the first refrigerant R1 may partially evaporate on the substrate 2.

[0093] As a result, the cooling device 10 can cool the region on the substrate 2, including the heat-generating element 3, by utilizing the latent heat of vaporization when the first refrigerant R1 evaporates.

[0094] (6) The cooling device 10 of the sixth embodiment is any cooling device 10 of (2) to (5), which may be provided with fins 11 in the region on the substrate 2 where the liquid film M of the first refrigerant R1 is formed.

[0095] As a result, the cooling device 10 can control the thickness of the liquid film M of the first refrigerant R1 by passing the fins 11 over the liquid film M of the first refrigerant R1. In addition, the fins 11 increase the contact area between the substrate 2 and the first refrigerant R1. That is, the heat transfer area between the substrate 2 and the first refrigerant R1 is increased.

[0096] (7) The cooling device 210 of the seventh embodiment is the cooling device 210 of (1), wherein the refrigerant supply units 30 and 230 may inject the first refrigerant R1 toward the heating element 3.

[0097] This allows the cooling device 210 to collide the first refrigerant R1 with the heat-generating element 3.

[0098] (8) The cooling device 210 of the eighth embodiment is the cooling device 210 of (7), further comprising fins 213 that are thermally connected to the heating element 3, and the refrigerant supply unit 230 may cause the first refrigerant R1 to collide with the fins 213.

[0099] This increases the contact area between the heating element 3 and the first refrigerant R1. In other words, the heat transfer area between the heating element 3 and the first refrigerant R1 is increased.

[0100] (9) The cooling device 210 of the ninth embodiment is the cooling device 210 of (8), wherein the refrigerant supply unit 230 injects the first refrigerant R1 so as it approaches the heating element 3, and the fins 213 may extend along the injection direction of the first refrigerant R1.

[0101] As a result, the cooling device 210 can suppress the scattering of the first refrigerant R1 sprayed onto the fins 213.

[0102] (10) The cooling device 210 of the tenth embodiment is any cooling device 210 of (1) to (9), wherein the storage tank 220 is equipped with a fan 212, the storage tank 220 houses the heating element 3 inside and stores the first refrigerant R1 in gas phase inside, and the fan 212 circulates the first refrigerant R1 in gas phase inside the storage tank 220.

[0103] This allows the fan 212 to circulate the gaseous first refrigerant R1 inside the storage tank 220. Therefore, the cooling device 210 can transfer the high-temperature heat accumulated above the storage tanks 20 and 220 to the liquid phase first refrigerant R1 stored at the bottom 221 of the storage tank 220. [Explanation of symbols]

[0104] 1…Server 2…Circulation board 3…Heating element 10…Cooling device 11…Fin 20…Storage tank 21…Bottom 30…Refrigerant supply unit 31…Circulation piping 31a…One end 31b…Other end 32…Pump 33…Header pipe 34…Supply port 40…Refrigerant cooling unit 41…Cooling fan 210…Cooling device 220…Storage tank 221…Bottom 222…Top 211…Relief valve 212…Fan 213…Fin 214…Heat transfer plate 230…Refrigerant supply unit 231…Circulation piping 231a…One end 231b…Other end 232…Pump 233…Filter 234…Injection unit 240…Refrigerant cooling unit 240A…Refrigerant cooling unit 241…Cooling tube 242…Tube fin 243…Casing 244...Propeller fan 245...Pan M...Liquid film R1...Primary refrigerant R2...Secondary refrigerant R21...Air

Claims

1. A storage tank for storing the liquid phase first refrigerant below the heating element, A refrigerant supply unit that pumps up the first refrigerant from the storage tank and supplies the first refrigerant to the heating element, A refrigerant cooling unit that cools the first refrigerant by supplying a second refrigerant at a lower temperature than the first refrigerant, thereby performing heat exchange between the first refrigerant and the second refrigerant, A fin that is thermally connected to the aforementioned heating element, Equipped with, The storage tank recovers the first refrigerant supplied to the heating element. The refrigerant supply unit injects the first refrigerant toward the heating element. The refrigerant supply unit causes the first refrigerant to collide with the fins, The refrigerant supply unit injects the first refrigerant so that it spreads radially as it approaches the heating element. The fins extend along the injection direction of the first refrigerant. Cooling device.

2. The storage tank is equipped with a fan, The storage tank houses the heating element inside and stores the first refrigerant in gaseous phase inside, The cooling device according to claim 1, wherein the fan circulates the first refrigerant in gaseous phase within the storage tank.

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