Cooling device

Abstract

A cooling device according to the present invention is provided with: a hollow housing having a bottom plate on which a heating element is placed, a top plate facing the bottom plate, and a side plate connecting the bottom plate and the top plate on the outer peripheral side; the heat exchange body is arranged on a bottom plate in the shell, so that a refrigerant can circulate in the heat exchange body; a supply unit for supplying a refrigerant from the outside into the housing; a discharge part for discharging the refrigerant from the inside of the housing to the outside; and a stirring unit that stirs the refrigerant in the heat exchanger.

Description

Technical Field

[0001] The invention relates to a cooling device.

[0002] This application claims priority based on patent application No. 2023-018433 filed in Japan on February 9, 2023, and incorporates the contents thereof herein. Background Art

[0003] In recent years, the high-density packaging of semiconductors has progressed, leading to an increasing trend in the amount of heat generated by CPUs and GPUs. Consequently, air cooling is insufficient to adequately cool heat-generating elements such as CPUs and GPUs. For example, a cold plate, such as the one disclosed in Patent Document 1, has been used to locally cool the heat-generating elements. The cold plate in Patent Document 1 includes a plate body that forms a refrigerant flow path. This cold plate boils the refrigerant within the plate body, extracting heat from the heat-generating element and cooling it.

[0004] Previous technical literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent No. 4410065 Summary of the Invention

[0007] Technical issues to be solved by the invention

[0008] In cooling devices that utilize refrigerant boiling, as semiconductors are increasingly densely packed, the heat flux on the heating surface of the cooling device increases, making the transition from nucleate boiling to film boiling more likely. In film boiling, a vapor film with low thermal conductivity forms between the heating element and the liquid refrigerant, reducing cooling efficiency. Consequently, the cooling device must be designed to be somewhat larger to prevent the transition from nucleate boiling to film boiling, which naturally limits the high-density packaging.

[0009] In view of this situation, it is required to suppress the transition from nucleate boiling to film boiling.

[0010] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a cooling device capable of suppressing the transition from nucleate boiling to film boiling.

[0011] Means for solving technical problems

[0012] In order to solve the above-mentioned problems, the cooling device involved in the present invention comprises: a shell, which has a bottom plate placed on the heating element, a top plate opposite to the bottom plate, and a side plate connecting the bottom plate and the top plate on the outer peripheral side, and is set to be hollow; a heat exchanger, which is arranged on the bottom plate in the shell so that the refrigerant can flow inside; a supply part, which supplies the refrigerant from the outside to the shell; a discharge part, which discharges the refrigerant from the inside of the shell to the outside; and a stirring part, which stirs the refrigerant in the heat exchanger.

[0013] Effects of the Invention

[0014] According to the cooling device of the present invention, the transition from nucleate boiling to film boiling can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a configuration diagram of a cooling system including a cooling device according to a first embodiment of the present invention.

[0016] Figure 2 It is a perspective view of the cooling device according to the first embodiment of the present invention.

[0017] Figure 3 It is a plan view of the cooling device according to the first embodiment of the present invention.

[0018] Figure 4 It is an enlarged side view showing the structure near the plate fins of the cooling device according to the first embodiment of the present invention.

[0019] Figure 5 This is a side view of a cooling device according to a second embodiment of the present invention.

[0020] Figure 6 It is an enlarged plan view showing a heat exchanger according to a second embodiment of the present invention.

[0021] Figure 7 This is a side view of a cooling device according to a first modified example of the second embodiment of the present invention.

[0022] Figure 8 This is a side view of a cooling device according to a second modified example of the second embodiment of the present invention.

[0023] Figure 9 This is a side view of a cooling device according to a third modified example of the second embodiment of the present invention.

[0024] Figure 10 This is a side view of a cooling device according to a third embodiment of the present invention. DETAILED DESCRIPTION

[0025] <First embodiment>

[0026] Below, reference Figures 1 to 4 , a cooling device 10 according to a first embodiment of the present invention will be described.

[0027] like Figure 1 As shown, a cooling device 10 according to the present embodiment is mounted on a cooling system 1 for cooling a server 4 . Figure 1 This is a schematic diagram showing the overall structure of the cooling system 1. In the illustrated example, servers 4 are housed within a rack 2 extending in the vertical direction Dv. Multiple server chassis 3 are inserted into the rack 2. The server chassis 3 is a box-shaped frame. Multiple server chassis 3 are arranged in the vertical direction Dv. Furthermore, multiple servers 4 are inserted into the server chassis 3. These servers 4 are inserted horizontally.

[0028] The server 4 includes a server housing 4a, a server motherboard 4b, and a chip (heat generating element) 4c, such as a CPU or GPU. The server housing 4a is a horizontally extending rectangular parallelepiped frame. The server motherboard 4b is housed within the server housing 4a. A chip 4c is mounted on the server motherboard 4b. Because the chip 4c generates heat during operation, a cooling system 1 is implemented to cool the chip 4c.

[0029] (Structure of cooling system)

[0030] The cooling system 1 includes a cooling device 10, a heat exchanger 5, a pump 6, and a control unit 7. The cooling device 10 is mounted on each chip 4c. A refrigerant F is supplied to the cooling device 10. The refrigerant F is, for example, a refrigerant of the HFC (Hydro Fluoro Carbon) or HFO (Hydro Fluoro Olefin) series, or water. The cooling device 10 is a cold plate that cools the chip 4c by exchanging heat between the refrigerant F and the chip 4c. The cooling device 10 of this embodiment cools a high-heat-generating heating element by boiling cooling of the refrigerant F. The cooling device 10 is connected to the heat exchanger 5 and the pump 6 through a refrigerant pipe 8. The refrigerant F heated by heat exchange with the chip 4c in the cooling device 10 is transported to the heat exchanger 5 through the refrigerant pipe 8. The heat exchanger 5 is a so-called condenser. The heat exchanger 5 cools the refrigerant F and condenses the gas-phase refrigerant F into the liquid-phase refrigerant F. The refrigerant F cooled by the heat exchanger 5 is sent to the pump 6 through the refrigerant pipe 8. The pump 6 again pressurizes and sends the refrigerant F toward the cooling device 10. The refrigerant F pressurized and sent to the cooling device 10 again exchanges heat with each chip 4c, thereby cooling each chip 4c.

[0031] Various devices constituting the cooling system 1 , such as the cooling device 10 , the heat exchanger 5 , and the pump 6 , are controlled by a control unit 7 .

[0032] In addition, Figure 1 In the figure, an example is shown in which three chips 4 c and cooling devices 10 are provided in each server 4 , but the number of chips 4 c and cooling devices 10 can be changed as appropriate. For example, approximately eight chips 4 c and cooling devices 10 can be provided in each server 4 .

[0033] (Structure of cooling device)

[0034] Hereinafter, the structure of the cooling device 10 will be described.

[0035] like Figure 2 、 Figure 3 As shown, cooling device 10 includes housing 11 , heat exchanger 20 , supply pipe (supply portion) 30 , discharge pipe (discharge portion) 40 , and stirring portion 70 .

[0036] Hereinafter, a predetermined direction intersecting the vertical direction Dv will be referred to as the first direction D1, and a direction intersecting the vertical direction Dv and the first direction D1 will be referred to as the second direction D2. In this embodiment, both the first direction D1 and the second direction D2 are horizontal directions. Furthermore, the first direction D1 and the second direction D2 are orthogonal to each other.

[0037] (case)

[0038] The housing 11 is hollow and made of a material with excellent thermal conductivity, such as metal. The housing 11 has an outer shape that resembles a horizontally flattened rectangular parallelepiped. When viewed from above in the vertical direction Dv, the four corners 11a of the housing 11 are curved, extending outward like chamfers. When viewed from above in the vertical direction Dv, the outer periphery of the housing 11 is approximately the same size as the outer periphery of the heating element.

[0039] The housing 11 can be designed to have any size.

[0040] For example, in this embodiment, the housing 11 is formed in a square shape when viewed from above in the vertical direction Dv. The height H1 of the housing 11 in the vertical direction Dv is, for example, approximately 10 mm, and the width W1 of the housing 11 in the first direction D1 and the width L1 in the second direction D2 are, for example, approximately 55 mm.

[0041] The housing 11 may be formed into a rectangular shape that is shorter in the second direction D2 than in the first direction D1. In this case, for example, the width L1 of the housing 11 in the second direction D2 may be approximately 30 mm.

[0042] The housing 11 includes a bottom plate 12 , a top plate 13 , and side plates 14 .

[0043] The base plate 12 is placed on the chip 4c and extends in the horizontal direction.

[0044] The top plate 13 is disposed above the bottom plate 12 and faces the bottom plate 12 in the up-down direction Dv. The top plate 13 extends in the horizontal direction.

[0045] The side panels 14 connect the bottom panel 12 and the top panel 13 on their outer peripheries. Four side panels 14 are positioned between the bottom panel 12 and the top panel 13. These four side panels 14 include two first side panels 14a facing each other in the first direction D1 and two second side panels 14b facing each other in the second direction D2. The first side panels 14a extend in the second direction D2, while the second side panels 14b extend in the first direction D1. Furthermore, each side panel 14 is positioned perpendicular to the top panel 13 and the bottom panel 12.

[0046] (Heat exchanger)

[0047] The heat exchanger 20 is provided on the bottom plate 12 within the shell 11. More specifically, when viewed from above in the vertical direction Dv, the heat exchanger 20 is arranged at a position overlapping with a region including the center of gravity of the shell 11 (hereinafter, this region may be referred to as the central portion Ac). In the present embodiment, when viewed from above in the vertical direction Dv, the center of gravity of the heat exchanger 20 is arranged at a position overlapping with the center of gravity of the shell 11. Hereinafter, the region within the shell 11 in which the heat exchanger is formed will be referred to as the heat exchange region A1. When viewed from above in the vertical direction Dv, the heat exchange region A1 includes the central portion Ac of the shell 11. The heat exchanger 20 is formed with an outer peripheral channel 15 defined between the heat exchanger 20 and the side plate 14 of the shell 11. When viewed from the vertical direction Dv, the outer peripheral channel 15 is formed in a rectangular frame shape. Furthermore, the refrigerant F can circulate within the heat exchanger 20. The details of the structure of the heat exchanger 20 will be described later.

[0048] (Supply pipe)

[0049] The supply pipe 30 is connected from the outside of the housing 11 to one of the first side plates 14a, one of the multiple side plates 14 that constitute the housing 11. The supply pipe 30 is a circular tube having a supply opening 31 that is connected to the side plate 14 and communicates with the interior of the housing 11. The supply opening 31 opens in a horizontal direction that intersects the vertical direction Dv. In this embodiment, the supply opening 31 is provided in the center of the first side plate 14a.

[0050] The supply pipe 30 is connected to the pump 6 via the refrigerant pipe 8 , and supplies the refrigerant F from the outside of the casing 11 to the outer peripheral channel 15 .

[0051] (Discharge pipe)

[0052] The discharge pipe 40 is connected to the top plate 13 constituting the shell 11 from the outside of the shell 11. More specifically, the discharge pipe 40 is connected to the area of ​​the top plate 13 that overlaps with the heat exchanger 20 when viewed from above in the up-down direction Dv. The discharge pipe 40 is a circular tube having a discharge opening 41 that is connected to the top plate 13 and communicates with the inside of the shell 11. The discharge opening 41 is open in the up-down direction Dv. When viewed from above in the up-down direction Dv, the center of the discharge opening 41 is arranged at a position that overlaps with the central portion Ac of the shell 11. In the present embodiment, the center of the discharge opening 41 is provided at a position in the central portion Ac that overlaps with the center of gravity of the shell 11 in the up-down direction Dv. Therefore, the discharge opening 41 overlaps with the heat exchanger 20 in the up-down direction Dv.

[0053] The discharge pipe 40 is connected to the heat exchanger 5 via the refrigerant pipe 8 , and discharges the refrigerant F from the inside of the shell 11 to the outside.

[0054] (Structure of heat exchanger)

[0055] Heat exchanger 20 of this embodiment includes partitions 21 , plate fins 22 , and sealing plates 24 .

[0056] (Separator)

[0057] The partition 21 of this embodiment is formed from a material with excellent thermal conductivity, such as metal, into a rectangular frame shape surrounding the exhaust pipe 40 when viewed from above in the vertical direction Dv. More specifically, the four corners 21c of the partition 21 are formed into a curved shape that extends outward, like chamfers, when viewed from above in the vertical direction Dv. In other words, the corners 21c of the partition 21 are formed to have the same shape as the corners 11a of the housing 11.

[0058] The partition 21 includes a first partition wall 21a and a second partition wall 21b. The first partition wall 21a is formed in a plate shape extending in the second direction D2 and is provided in a pair in the first direction D1. The second partition wall 21b is formed in a plate shape extending in the first direction D1 and is provided in a pair in the second direction D2. The pair of second partition walls 21b are respectively connected to the ends of the first partition wall 21a in the second direction D2. A plurality of slits 23 are formed in the second partition wall 21b and pass through the second partition wall 21b in the second direction D2. The inlet extends in the first direction D1. The lower edge of the slit 23 contacts the bottom plate 12. On the other hand, the upper edge of the slit 23 is located below the top plate 13.

[0059] The partition 21 blocks the flow of the refrigerant F supplied from the supply pipe 30 in the first direction D1 by the first partition wall 21 a on the supply pipe 30 side, and separates the flow of the refrigerant F into both sides in the second direction D2 .

[0060] The partition portion 21 of this embodiment connects the bottom plate 12 and the top plate 13 .

[0061] (Plate fin)

[0062] A plurality of plate fins 22 are arranged on the inner side of the partition 21 in the first direction D1. Each plate fin 22 is a rectangular plate-shaped component extending in the second direction D2. The plate fin 22 is formed of a material with excellent thermal conductivity such as metal. In the present embodiment, the plate fin 22 is formed of copper. Therefore, the surface temperature of the plate fin 22 becomes uniform. The plate fin 22 extends upward from the bottom plate 12. The upper edge of the plate fin 22 is separated from the top plate 13, and a predetermined gap C1 is provided between the plate fin 22 and the top plate 13. In addition, the plate fin 22 can also be formed to the same height as the partition 21. In addition, each plate fin 22 is arranged in a posture perpendicular to the bottom plate 12.

[0063] The plurality of plate fins 22 are arranged so as to oppose each other in the second direction D2. A pair of plate fins 22 opposing each other in the second direction D2 is arranged along the second partition wall 21b, with each plate fin 22 extending from the second partition wall 21b in the first direction D1. Furthermore, when viewed from the side in the second direction D2, the plurality of plate fins 22 are positioned below the upper ends of the slits 23 formed in the partition portion 21.

[0064] The plurality of plate fins 22 form gaps S1 between the plate fins 22 that are narrow enough to act as flow resistance for the refrigerant F. The gaps S1 between the plate fins 22 communicate with the slits 23 of the partition 21 .

[0065] The pitch P1 between the plate fins 22 is, for example, 0.5 mm or more and 1.0 mm or less. The thickness T1 of the plate fin 22 is, for example, approximately 0.5 mm, and the height H2 of the plate fin 22 is, for example, 5.0 mm.

[0066] (Closed plate)

[0067] The closing plate 24 is provided at the end portion on the inner side of the plate fin 22 in the second direction D2. That is, the closing plate 24 is provided at the end portion on the side opposite to the second partition wall 21b in the second direction D2 of the plate fin 22. The closing plate 24 extends in the first direction D1 and connects a pair of opposing first partition walls 21a. Moreover, the closing plate 24 is arranged to be orthogonal to the bottom plate 12 and connects the bottom plate 12 and the top plate 13. The closing plate 24 is formed of a material having excellent thermal conductivity, such as metal. Similar to the second partition wall 21b of the partition 21, a plurality of slits 23 arranged in the first direction D1 are formed on the closing plate 24.

[0068] (Mixing section)

[0069] The stirring portion 70 stirs the refrigerant F in the heat exchanger 20. Figure 4As shown, the stirring portion 70 of this embodiment comprises a plurality of particles 71 disposed within the heat exchanger 20. Particles 71 are disposed in the gaps S1 between the plate fins 22. Each particle 71 is formed into a bead (spherical) shape using, for example, metal, resin, or polymer. The diameter of particle 71 is larger than the width of slits 23 provided in the partition 21 or the sealing plate 24. This allows refrigerant F to circulate within the heat exchanger 20 while preventing particles 71 from escaping from the gaps between the plate fins 22. The diameter of particle 71 ranges from several μm to approximately 1 mm, for example.

[0070] In this embodiment, a plurality of particles 71 are provided in the gap S1 between the slits 23 so that the density of the particles 71 becomes 500 kg / m 3 Above and 2000kg / m 3 the following.

[0071] (Effect)

[0072] Next, the effects of the cooling device 10 will be described.

[0073] First, the flow of the refrigerant F in the cooling device 10 will be described.

[0074] The refrigerant F supplied from the supply pipe 30 into the shell 11 flows into the peripheral channel 15. Therefore, the refrigerant F is separated to both sides of the second direction D2 through the peripheral channel 15 and flows around the heat exchanger 20. Then, the refrigerant F is supplied to the heat exchanger 20. In this embodiment, the refrigerant F is supplied from both sides of the second direction D2. The refrigerant F flows from the peripheral side toward the central portion Ac side when viewed from above through the space between the plate fins 22. At this time, the plate fins 22 are completely immersed in the refrigerant F. The refrigerant F exchanges heat with the chip 4c via the plate fins 22, the plurality of particles 71 and the bottom plate 12. As a result, the chip 4c is cooled. On the other hand, the refrigerant F is heated by the heat of the chip 4c. The refrigerant F evaporates due to the heat of the chip 4c and changes from liquid-phase refrigerant F to gas-phase refrigerant F. The heated refrigerant F is discharged directly from the heat exchanger 20 to the outside of the shell 11 via the discharge pipe 40.

[0075] In the present embodiment, cooling device 10 includes stirring portion 70 for stirring refrigerant F in heat exchanger 20 .

[0076] This allows the refrigerant F inside the heat exchanger 20 to be stirred. Consequently, bubbles generated during boiling of the refrigerant F are less likely to coalesce, and the transition point from nucleate boiling to film boiling can be shifted toward the higher heat flux side (higher temperature side). Consequently, the transition from nucleate boiling to film boiling can be suppressed.

[0077] In this embodiment, stirring portion 70 is a plurality of particles 71 arranged on heat exchanger 20 .

[0078] According to the present embodiment, fine gaps through which the refrigerant F can flow are formed between the plurality of particles 71. The refrigerant F is dispersed and rises through the gaps between these plurality of particles 71. Moreover, the plurality of particles 71 move within the heat exchanger 20 due to the flow of the refrigerant F or the lift generated when the refrigerant F boils. As a result, the refrigerant F is stirred, and bubbles generated by the boiling of the refrigerant F become difficult to merge. Therefore, the transition point from nucleate boiling to film boiling can be moved to the high heat flux side. Therefore, by configuring a simple structure with only a plurality of particles 71, the transition from nucleate boiling to film boiling can be suppressed.

[0079] Furthermore, the plurality of particles 71 move within the heat exchanger 20, so the particles 71 repeatedly come into contact with the heat exchanger 20. To explain in detail, first, the particles 71 come into contact with the heat exchanger 20, transferring heat from the heat exchanger 20 to the heat source. Then, the particles 71 separate from the heat exchanger 20, and the entire surface of the particles 71 exchanges heat with the refrigerant F, so that the heat of the heat source is further transferred from the particles 71 to the refrigerant F. Next, the particles 71 come into contact with the heat exchanger 20 again, absorbing the heat of the heat source through the heat exchanger 20. By repeating this process, heat exchange between the refrigerant F and the heat source is further effectively performed. Therefore, the cooling efficiency can be improved.

[0080] Furthermore, these particles 71 can also absorb impurities such as dirt, moisture, and oil. Thus, the cooling device 10 can purify the refrigerant F flowing through the heat exchanger 20. This promotes heat exchange between the refrigerant F and the heat exchanger, further improving cooling efficiency.

[0081] Examples of methods for imparting the function of absorbing impurities to the plurality of particles 71 include forming the particles 71 with a specific adsorption material, increasing the density of the particles 71 to capture impurities in gaps between the particles 71, and the like.

[0082] In the present embodiment, heat exchanger 20 further includes a plurality of plate fins 22 arranged in first direction D1 and extending in second direction D2 . Particles 71 are disposed in gaps S1 between plate fins 22 .

[0083] Thus, the plurality of particles 71 can be moved within the gaps S1 between the plate fins 22. This suppresses the displacement of the plurality of particles 71, and allows the refrigerant F to be uniformly stirred within the heat exchanger 20. Consequently, the merging of bubbles generated by the boiling of the refrigerant F is further suppressed. Consequently, the transition point from nucleate boiling to film boiling can be shifted toward a higher heat flux. Therefore, with a simple structure consisting solely of the plurality of particles 71, the transition from nucleate boiling to film boiling can be further suppressed.

[0084] In this embodiment, a plurality of particles 71 are provided in the gaps between the slits 23 so that the density of the particles 71 becomes 500 kg / m 3 Above and 2000kg / m 3 the following.

[0085] As a result, when the heat flux increases and the boiling of the refrigerant F is promoted, the movement of the particles 71 becomes more active. Therefore, the refrigerant F can be further agitated on the boiling surface within the shell 11. Consequently, the transition point from nucleate boiling to film boiling can be shifted toward a higher heat flux. Consequently, the transition from nucleate boiling to film boiling can be further suppressed.

[0086] In this embodiment, the density of the plurality of particles 71 is 500 kg / m 3 Above and 2000kg / m 3 The following is an explanation of the situation, but it is not limited to this. The density of the plurality of particles 71 can be appropriately changed according to the situation. However, when the density of the plurality of particles 71 is 500 kg / m 3 Above and 2000kg / m 3 In the following cases, there is an advantage in activating the movement of the particles 71 .

[0087] In addition, in this embodiment, a plurality of slits 23 arranged at equal intervals in the second direction D2 are formed on the second partition wall 21b, but the present invention is not limited thereto. Instead of these multiple slits 23, circular or polygonal fine through-holes or the like may be provided on the second partition wall 21b. These through-holes need to be formed to be smaller than the diameter of the particles 71. Furthermore, as long as the refrigerant F can flow through the heat exchanger 20 and the particles 71 can be prevented from flowing out of the slits 23, for example, a mesh material may be provided instead of the second partition wall 21b having the slits 23. Furthermore, for example, the second partition wall 21b and the sealing plate 24 may not be provided, and the plate fins 22 may be formed thicker at both ends in the second direction D2 in the first direction D1. Thus, at both ends in the second direction D2 of the plate fins 22, the gap S1 between the plate fins 22 is made smaller than the diameter of the particles 71, thereby preventing the particles 71 from flowing out of the gap between the plate fins 22.

[0088] In this embodiment, the partition 21 is formed to connect the bottom plate 12 and the top plate 13 in the vertical direction Dv, but the present invention is not limited thereto. The partition 21 may be formed to extend upward from the bottom plate 12 and to be separated downward from the top plate 13.

[0089] <Second embodiment>

[0090] Below, reference Figure 5 、 Figure 6A cooling device 210 according to a second embodiment of the present invention will be described. Configurations of the second embodiment that are common to those of the first embodiment are denoted by the same names and reference numerals, and description thereof will be omitted as appropriate.

[0091] like Figure 5 、 Figure 6 As shown, in this embodiment, the heat exchanger 220 includes grille fins 60 and pin fins 250 .

[0092] (Grill fin)

[0093] The grille fins 60 extend horizontally, intersecting the vertical direction Dv. Furthermore, each grille 63 of the grille fin 60 is formed into a square shape by combining first posts 61 extending in the first direction D1 and second posts 62 extending in the second direction D2. The shortest width between the inner edges of the grilles 63 is referred to as the "grille diameter R1." In this embodiment, since the grilles 63 are formed into a square shape, the length of one side of the grille 63 is the grille diameter R1.

[0094] The first pillar 61 and the second pillar 62 are both formed in a cylindrical shape. In addition, the shapes of the first pillar 61 and the second pillar 62 can be changed as appropriate. For example, the first pillar 61 and the second pillar 62 can both be in a quadrangular pillar shape.

[0095] A plurality of grille fins 60 are arranged at equal intervals in the vertical direction Dv. Hereinafter, the pitch between the plurality of grille fins 60 is referred to as a first pitch P2. Furthermore, adjacent grille fins 60 are staggered in a direction intersecting the vertical direction Dv (in this embodiment, the horizontal direction).

[0096] The plurality of grille fins 60 include first grille fins 60a and second grille fins 60b. The first grille fins 60a and second grille fins 60b are arranged alternately in the vertical direction Dv. The first grille fins 60a and second grille fins 60b are staggered. Therefore, when viewed from above in the vertical direction Dv, the grille points 64 of the second grille fins 60b are located at the center of the grilles 63 of the first grille fins 60a. The first grille fins 60a are arranged at the same horizontal position, and the second grille fins 60b are arranged at the same horizontal position.

[0097] In the illustrated example, the first grille fins 60a are provided in two stages and the second grille fins 60b are provided in one stage, but the present invention is not limited thereto. The number of stages of the first grille fins 60a and the number of stages of the second grille fins 60b can be changed as appropriate.

[0098] Furthermore, a predetermined gap C1 is provided between the top plate 13 and the uppermost grille fin 60 among the plurality of grille fins 60 .

[0099] (Pin fin)

[0100] The pin fins 250 extend in the vertical direction Dv and serve as struts supporting the grid fins 60. When viewed from above in the vertical direction Dv, the pin fins 250 are arranged in a grid pattern extending in the first direction D1 and the second direction D2. Herein, the row of pin fins 250 extending in the first direction D1 is referred to as the first pin row 251, and the row of pin fins 250 extending in the second direction D2 is referred to as the second pin row 252. Adjacent first pin rows 251 are arranged with a staggered arrangement. Therefore, the multiple pin fins 250 forming a group of adjacent first pin rows 251 are arranged in a zigzag pattern extending in the first direction D1. Similarly, adjacent second pin rows 252 are arranged with a staggered arrangement. Therefore, the multiple pin fins 250 forming a group of adjacent second pin rows 252 are arranged in a zigzag pattern extending in the second direction D2.

[0101] Furthermore, the pitch between the pin fins 250 constituting the second needle row 252 is narrower than the pitch between the pin fins 250 constituting the first needle row 251. Hereinafter, the pitch between the pin fins 250 constituting the second needle row 252 is referred to as a second pitch P3.

[0102] The pitch between the pin fins 250 constituting the first pin row 251 may be narrower than the pitch between the pin fins 250 constituting the second pin row 252. In this case, the pitch between the pin fins 250 constituting the first pin row 251 is the second pitch P3.

[0103] Each pin fin 250 is perpendicular to the grid fin 60. In this embodiment, the pin fin 250 is formed in a cylindrical shape. In addition, the shape of the pin fin 250 can be changed as appropriate. For example, the pin fin 250 can be formed in a quadrangular prism shape.

[0104] Next, the dimensions of the above-mentioned grid fins 60 and pin fins 250 will be described.

[0105] The grid diameter R1 of the grid fins 60, the first pitch P2, and the second pitch P3 of the pin fins 250 are preferably all at least several tens of μm. For example, the grid diameter R1 is designed to be 300 μm, the first pitch P2 is designed to be 150 μm, and the second pitch P3 is designed to be between 0.45 mm and 0.6 mm. Furthermore, the height H3 of the pin fins 250 in the vertical direction Dv is designed to be, for example, 3 mm.

[0106] The dimensions of the grid fins 60 and the pin fins 250 can be changed as appropriate.

[0107] (Mixing section)

[0108] The stirring unit 270 includes a valve 72 (flow rate adjustment unit) provided on the supply pipe 30 to adjust the flow rate of the refrigerant F flowing in the supply pipe 30. The valve 72 is, for example, received by the control unit 7 (refer to Figure 1 ) to adjust the opening of the inlet pipe.

[0109] (Effect)

[0110] Next, the effects of the cooling device 210 will be described.

[0111] In the present embodiment, the stirring portion 270 includes a valve 72 provided in the supply pipe 30 to adjust the flow rate of the refrigerant F flowing through the supply pipe 30 .

[0112] According to this embodiment, the amount of refrigerant F supplied to the shell 11 can be changed in a short period of time. This allows the flow of the refrigerant F to be vibrated. Consequently, the refrigerant F can be stirred on the boiling surface within the shell 11. Consequently, the transition point from nucleate boiling to film boiling can be moved toward the high heat flux side. Consequently, the transition from nucleate boiling to film boiling can be suppressed. Furthermore, by adjusting the flow rate, optimal vibration can be achieved.

[0113] In the above embodiment, the flow rate adjustment unit is described as the valve 72 that adjusts the opening of the inlet pipe, but the present invention is not limited to this. The flow rate adjustment unit may also be a pump. Furthermore, the flow rate adjustment unit may include the valve 72 and the pump.

[0114] <First Modification of Second Embodiment>

[0115] Next, refer to Figure 7 , a first variation of the second embodiment is described.

[0116] like Figure 7 As shown, in this modification, the stirring portion 270 includes, in addition to the valve 72, a plurality of particles 71, such as those of the first embodiment, disposed on the heat exchanger 220. The diameter of these particles 71 is preferably smaller than the grid diameter R1 and the first pitch P2 of the grid fins 60, and the second pitch P3 of the pin fins 250.

[0117] In addition, the particles included in the stirring section 270 of the present embodiment are not limited to the particles 71 of the first embodiment, and the shape and material can be changed as appropriate.

[0118] Thus, due to the vibration of the flow of refrigerant F caused by the change in the supply amount of refrigerant F, the multiple particles 71 are actively moved within the heat exchanger 220. Therefore, in addition to the vibration of the flow, the active movement of the multiple particles 71 can also exert an action on the boundary layer near the boiling surface within the shell 11. Therefore, the mixing of the high-temperature fluid near the boiling surface and the surrounding low-temperature fluid is promoted. Therefore, the transition point from nucleate boiling to film boiling can be moved to the side with higher heat flux. Therefore, the transition from nucleate boiling to film boiling can be further suppressed.

[0119] <Second Modification of Second Embodiment>

[0120] Next, refer to Figure 8 , a second variation of the second embodiment is described.

[0121] like Figure 8 As shown, in this modification, the stirring portion 270 includes a sonic wave portion 73 that propagates sonic waves SW in the housing 11 in addition to the valve 72 .

[0122] Thus, the stirring portion 270 can further stir the refrigerant F by applying the sound waves SW to the refrigerant F. Therefore, the transition point from nucleate boiling to film boiling can be shifted to a higher heat flux side. Therefore, the transition from nucleate boiling to film boiling can be further suppressed.

[0123] <Third Modification of Second Embodiment>

[0124] Next, refer to Figure 9 , a third variation of the second embodiment is described.

[0125] like Figure 9 As shown, in this modification, the stirring portion 270 includes the plurality of particles 71 of the first modification and the sonic wave portion 73 of the second modification in addition to the valve 72 .

[0126] Thus, the stirring section 270 vibrates due to the flow rate adjustment by the valve 72, and the particles 71 are vigorously moved by the sound waves SW propagated from the sound wave section 73. As a result, the refrigerant F is further stirred. Consequently, the transition point from nucleate boiling to film boiling can be shifted toward a higher heat flux. Consequently, the transition from nucleate boiling to film boiling can be further suppressed.

[0127] <Third embodiment>

[0128] Below, reference Figure 10 A cooling device 310 according to a third embodiment of the present invention will be described. Configurations in the third embodiment that are common to those in the above-described embodiments are denoted by the same names and reference numerals, and descriptions thereof will be omitted as appropriate.

[0129] like Figure 10 As shown, in this embodiment, the stirring section 370 includes a plurality of particles (moving bodies) 371 and a magnetic section 74. The plurality of particles 371 are formed of a magnetic material. The plurality of particles 371 are disposed within the heat exchanger 320. The magnetic section 74 is provided on the outer periphery of the housing 11. In this embodiment, the magnetic section 74 is provided so as to clamp the housing 11 from the first direction D1. The magnetic section 74 applies a magnetic force to the plurality of particles 371 within the housing 11.

[0130] (Effect)

[0131] Next, the effects of the cooling device 310 will be described.

[0132] In this embodiment, the stirring unit 370 may include a plurality of particles 371 disposed on the heat exchanger 320 and a magnetic unit 74 that applies a magnetic force to the plurality of particles 371 .

[0133] According to this embodiment, the plurality of particles 371 are actively moved within the heat exchanger 320 by magnetic force. This further suppresses the merging of bubbles generated by the boiling of the refrigerant F. Consequently, the transition point from nucleate boiling to film boiling can be shifted toward a higher heat flux. Consequently, the transition from nucleate boiling to film boiling can be further suppressed.

[0134] In addition, in this embodiment, the moving body is described as a case where the plurality of particles 371 are used, but the present invention is not limited thereto. The moving body may be formed in the shape of a magnetic propeller, for example.

[0135] (Other Implementation Methods)

[0136] While the embodiments of the present invention have been described in detail with reference to the drawings, the specific configuration is not limited to the embodiments and includes design changes within the scope of the present invention.

[0137] In the above embodiments, the cooling devices 10, 210, and 310 are described as cold plates for cooling chips 4c such as CPUs and GPUs mounted in the server 4. However, the present invention is not limited thereto. The cooling devices 10, 210, and 310 may also cool heat generating bodies other than the chips 4c.

[0138] In the above embodiment, the case where the shell 11 is formed into a rectangular parallelepiped is described, but the present invention is not limited to this. The shell 11 can be formed into a polygonal shape other than a rectangular parallelepiped, for example, it can be formed into a circular plate shape. Similarly, the shape of the heat exchanger 20, 220, 320 is not limited to a rectangular parallelepiped, and the shape of the peripheral channel 15 is not limited to a rectangular frame shape. That is, the heat exchanger 20, 220, 320 can be formed into a polygonal shape other than a rectangular parallelepiped, for example, it can be formed into a circular plate shape. Furthermore, the peripheral channel 15 can be formed into a polygonal frame shape other than a rectangle, for example, it can be formed into a circular ring shape.

[0139] In the above embodiment, the supply portion is a supply pipe 30 having a supply opening 31, and the discharge portion is a discharge pipe 40 having a discharge opening 41, but the present invention is not limited to this. The supply portion may be composed only of the supply opening 31, and the discharge portion may be composed only of the discharge opening 41. In this case, the refrigerant pipe 8 is directly connected to the supply opening 31 and the discharge opening 41. In addition, although the supply opening 31 is connected to the side plate 14, the present invention is not limited to this. The supply opening 31 may be connected, for example, to a position in the top plate 13 that overlaps with the peripheral channel 15 in the vertical direction Dv. In addition, the discharge opening 41 is connected to the top plate 13 in the central portion Ac of the shell 11, but the present invention is not limited to this. As long as the discharge opening 41 is in a position that overlaps with the heat exchanger 20, 220, 320 in the vertical direction Dv, it can be arranged on the peripheral side of the central portion Ac of the shell 11 when viewed from above in the vertical direction Dv.

[0140] <Note>

[0141] The cooling devices 10 , 210 , and 310 described in the respective embodiments are understood, for example, as follows.

[0142] (1) The cooling device 10, 210, 310 involved in the first embodiment comprises: a shell 11 having a bottom plate 12 placed on a heating element, a top plate 13 opposite to the bottom plate 12, and a side plate 14 connecting the bottom plate 12 and the top plate 13 on the outer peripheral side, and being configured to be hollow; a heat exchanger 20, 220, 320, which is arranged on the bottom plate 12 in the shell 11 so that the refrigerant F can flow inside; a supply portion for supplying the refrigerant F from the outside into the shell 11; a discharge portion for discharging the refrigerant F from the inside of the shell 11 to the outside; and a stirring portion 70, 270, 370 for stirring the refrigerant F in the heat exchanger 20, 220, 320.

[0143] As an example of a heat generating element, the chip 4c in the above-mentioned embodiment can be cited.

[0144] Examples of the supply portion include the supply pipe 30 in the above-described embodiment, and examples of the discharge portion include the discharge pipe 40 in the above-described embodiment.

[0145] This can stir refrigerant F inside heat exchangers 20, 220, 320. Therefore, bubbles generated during boiling of refrigerant F are less likely to coalesce, and the transition point from nucleate boiling to film boiling can be moved to a higher heat flux side (higher temperature side).

[0146] (2) The cooling device 10 according to the second aspect is the cooling device 10 according to the first aspect, wherein the stirring portion 70 may be a plurality of particles 71 arranged on the heat exchanger 20 .

[0147] According to this embodiment, fine gaps S1 are formed between the particles 71, through which the refrigerant F can flow. The refrigerant F is dispersed and rises through these gaps S1 between the particles 71. Furthermore, the particles 71 are moved within the heat exchanger 20 by the flow of the refrigerant F or the lift generated by the boiling of the refrigerant F. This makes it difficult for bubbles generated by the boiling of the refrigerant F to merge. Consequently, the transition point from nucleate boiling to film boiling can be shifted toward a higher heat flux.

[0148] (3) The cooling device 10 involved in the third embodiment is the cooling device 10 of the second embodiment, wherein the heat exchanger 20 has a plurality of plate fins 22 arranged in a first direction D1 intersecting the vertical direction Dv, each of the plate fins 22 extends in a second direction D2 intersecting the vertical direction Dv and the first direction D1, and the plurality of particles 71 can be arranged in gaps S1 between the plate fins 22.

[0149] According to this embodiment, particles 71 can be moved in gaps S1 between plate fins 22. This prevents particles 71 from being displaced, and allows refrigerant F to be uniformly stirred in heat exchanger 20.

[0150] (4) The cooling device 10 according to the fourth embodiment is the cooling device 10 according to the second embodiment or the third embodiment, wherein the plurality of particles 71 may be arranged so that the density of the plurality of particles 71 becomes 500 kg / m 3 Above and 2000kg / m 3 the following.

[0151] As a result, when the heat flux increases and the boiling of the refrigerant F is promoted, the movement of the particles 71 becomes active. Therefore, the refrigerant F can be further stirred on the boiling surface in the housing 11. Therefore, the transition point from nucleate boiling to film boiling can be moved to the higher heat flux side.

[0152] (5) The cooling device 210 according to the fifth aspect is the cooling device 210 according to the first aspect, wherein the stirring portion 270 may include a flow rate adjustment portion provided in the supply portion to adjust the flow rate of the refrigerant F flowing in the supply portion.

[0153] As an example of the flow rate adjustment unit, the valve 72 in the above-mentioned embodiment and the like can be cited.

[0154] According to this embodiment, the amount of refrigerant F supplied to the shell 11 can be changed in a short period of time. This allows the flow of the refrigerant F to be vibrated. Consequently, the refrigerant F can be stirred on the boiling surface within the shell 11. Consequently, the transition point from nucleate boiling to film boiling can be shifted toward a higher heat flux.

[0155] (6) The cooling device 210 according to the sixth aspect is the cooling device 210 according to the fifth aspect, wherein the stirring section 270 may further include a plurality of particles 71 disposed on the heat exchanger 220 .

[0156] Thus, the refrigerant F flow vibrations caused by changes in the refrigerant F supply rate cause the particles 71 to actively move within the heat exchanger 220. Therefore, in addition to the flow vibrations, the active movement of the particles 71 can also act on the boundary layer near the boiling surface within the shell 11. This promotes mixing between the high-temperature fluid near the boiling surface and the surrounding low-temperature fluid. Consequently, the transition point from nucleate boiling to film boiling can be shifted toward a higher heat flux.

[0157] (7) The cooling device 210 according to the seventh aspect is the cooling device 210 according to the fifth or sixth aspect, wherein the stirring portion 270 may further include a sonic wave portion 73 that propagates the sonic wave SW in the housing 11 .

[0158] Thus, the stirring portion 270 can further stir the refrigerant F by applying the sound waves SW to the refrigerant F. Therefore, the transition point from nucleate boiling to film boiling can be shifted to a higher heat flux side.

[0159] (8) The cooling device 310 according to the eighth aspect is the cooling device 310 according to the first aspect, wherein the stirring portion 370 may include: a moving body disposed on the heat exchanger 320 and formed of a magnetic body; and a magnetic portion 74 for applying a magnetic force to the moving body.

[0160] Examples of the moving body include the plurality of particles 371 in the above-described embodiment.

[0161] According to this embodiment, the moving body is actively moved by magnetic force within heat exchanger 320. This further suppresses the coalescence of bubbles caused by boiling of refrigerant F. Consequently, the transition point from nucleate boiling to film boiling can be shifted toward a higher heat flux.

[0162] Industrial applicability

[0163] According to the cooling device of the present invention, the transition from nucleate boiling to film boiling can be suppressed.

[0164] Explanation of symbols

[0165] 1-Cooling system, 2-Rack, 3-Server chassis, 4-Server, 4a-Server housing, 4b-Server motherboard, 4c-Chip (heat generating element), 5-Heat exchanger, 6-Pump, 7-Control unit, 8-Refrigerant pipe, 10-Cooling device, 11-Casing, 11a-Corner, 12-Bottom plate, 13-Top plate, 14-Side plate, 14a-1st side plate, 14b-2nd side plate, 15-Peripheral channel, 20-Heat exchanger, 21-Partition, 21a-1st partition wall, 21b-2nd partition wall, 21c-Corner, 22-Plate fin, 23-Slit, 24-Closing plate, 30-Supply pipe (supply portion), 31-Supply opening, 40-Discharge pipe (discharge portion), 41-Discharge opening, 50-Pin fin, 60-Grid fin, 60a-1st grid fin, 60b-2nd grid fin, 61 -1st column, 62-2nd column, 63-grid, 64-grid point, 70-stirring section, 71-particle, 72-valve (flow adjustment section), 73-sonic wave section, 74-magnetic section, 210-cooling device, 220-heat exchanger, 250-pin fin, 251-1st pin row, 252-2nd pin row, 270-stirring section, 310-cooling device, 320-heat exchanger, 370-stirring section, 371-particle (moving body), A1-heat exchange area, Ac-central section, C1-gap, Dv-vertical direction, D1-1st direction, D2-2nd direction, F-refrigerant, H1-height, H2-height, H3-height, L1-width, P1-pitch, P2-1st pitch, P3-2nd pitch, R1-grid diameter, S1-gap, SW-sonic wave, T1-thickness, W1-width.

Claims

1. A cooling device comprising: The housing has a bottom plate placed on the heating element, a top plate facing the bottom plate, and a side plate connecting the bottom plate and the top plate at the outer periphery, and is hollow; a heat exchanger disposed on the bottom plate within the shell to allow refrigerant to circulate therein; a supply unit for supplying refrigerant into the shell from the outside; a discharge portion for discharging the refrigerant from the shell to the outside; and The stirring unit stirs the refrigerant in the heat exchanger.

2. The cooling device according to claim 1, wherein: The stirring portion is a plurality of particles disposed on the heat exchanger.

3. The cooling device according to claim 2, wherein: The heat exchanger has a plurality of plate fins arranged in a first direction intersecting the vertical direction. Each of the plate fins extends in a second direction intersecting the vertical direction and the first direction. The plurality of particles are arranged in gaps between the plate fins.

4. The cooling device according to claim 2 or 3, wherein: The plurality of particles are arranged so that the density of the plurality of particles becomes 500 kg / m 3 Above and 2000kg / m 3 the following.

5. The cooling device according to claim 1, wherein The stirring portion includes a flow rate adjusting portion provided at the supply portion to adjust a flow rate of the refrigerant flowing through the supply portion.

6. The cooling device according to claim 5, wherein: The stirring unit further includes a plurality of particles disposed on the heat exchanger.

7. The cooling device according to claim 5 or 6, wherein: The stirring portion further includes a sonic wave portion that propagates sonic waves within the housing.

8. The cooling device according to claim 1, wherein: The stirring part has: a moving body, disposed on the heat exchange body and formed of a magnetic body; and The magnetic part applies a magnetic force to the moving body.

Images