Cooling device

Abstract

To provide a cooling apparatus that can improve cooling efficiency.SOLUTION: A cooling apparatus 10 comprises: a hollow casing 11 having a bottom plate 12 placed on a heating element, a top plate 13 opposite the bottom plate, and side plates 14 connecting the bottom plate and the top plate at the outer periphery; a heat exchanger 20 provided on the bottom plate in the hollow casing, forming a peripheral passage 15 between the bottom plate and the side plate of the hollow casing, and having a plurality of plate fins 22, through which a refrigerant can circulate inside; a supply section 30 that supplies refrigerant from the outside to the peripheral passage; and a discharge section 40 connected to the area overlapping the heat exchanger in plan view on the top plate to discharge refrigerant from inside the hollow casing to the outside.SELECTED DRAWING: Figure 2

Description

Technical Field

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

Background Art

[0002] In recent years, three-dimensional mounting of semiconductors has been progressing, and the heat generation amount of CPUs and GPUs has been increasing. Therefore, with air cooling, heat generating bodies such as CPUs and GPUs cannot be sufficiently cooled, and thus, for example, measures have been taken to locally cool the heat generating body with a cold plate or the like disclosed in Patent Document 1. The cold plate of Patent Document 1 has a plate body in which a refrigerant flow path is formed. In addition, a plurality of heat generating bodies such as CPUs and GPUs are installed in a server, and it is necessary to supply refrigerant to the cold plates provided for each heat generating body.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when attempting to supply refrigerant to a plurality of cold plates, the refrigerant cannot be sufficiently supplied to each cold plate, and a bias occurs in the supply amount of the refrigerant within the cold plate. In particular, when cooling a high heat generating heat generating body by boiling the refrigerant, the bias in the supply amount of the refrigerant within the cold plate becomes large, and there are cases where the heat generating body cannot be sufficiently cooled. Due to such circumstances, development of a highly efficient cooling device that can cool a high heat generating heat generating body while stabilizing the supply amount of the refrigerant within the cold plate has been desired.

[0005] This disclosure was made to solve the above-mentioned problems and aims to provide a cooling device that can improve cooling efficiency. [Means for solving the problem]

[0006] To solve the above problems, the cooling device according to the present disclosure has a hollow casing having a bottom plate on which a heating element is placed, a top plate opposite to the bottom plate, and side plates connecting the bottom plate and the top plate on the outer circumference, and a casing provided on the bottom plate within the casing between the side plates of the casing When viewed from above or below, it forms a frame-like shape. The outer perimeter passage is demarcated. Having a frame-shaped partition Along with, From the aforementioned outer perimeter passage The device comprises a heat exchanger through which a refrigerant can circulate, a supply unit that supplies refrigerant from the outside to the outer peripheral passage, and a discharge unit connected to a region of the top plate that overlaps with the heat exchanger in a plan view, and which discharges refrigerant from inside the casing to the outside.

[0007] The cooling device according to this disclosure comprises a hollow casing having a bottom plate on which a heating element is placed, a top plate opposite the bottom plate, and side plates connecting the bottom plate and the top plate on the outer periphery; a heat exchanger provided on the bottom plate within the casing, through which a refrigerant can flow; a supply unit for supplying refrigerant into the casing from the outside; and a discharge unit connected to a region of the top plate that overlaps the heat exchanger in a plan view, for discharging refrigerant from the casing to the outside, wherein the heat exchanger has a plurality of grid fins that extend so as to intersect in the vertical direction and are arranged vertically, and adjacent grid fins are offset from each other in a direction that intersects in the vertical direction. The plurality of grid fins include a first grid fin and a second grid fin, the first grid fin and the second grid fin are arranged alternately in the vertical direction, and in a vertical plan view, the grid points of the second grid fin are located at the center of the grid of the first grid fin. . [Effects of the Invention]

[0008] The cooling device of this disclosure can improve cooling efficiency. [Brief explanation of the drawing]

[0009] [Figure 1] This is a diagram showing the configuration of a cooling system equipped with a cooling device according to the first embodiment of this disclosure. [Figure 2] It is a perspective view of the cooling device according to the first embodiment of the present disclosure. [Figure 3] It is a plan view of the cooling device according to the first embodiment of the present disclosure. [Figure 4] It is an enlarged side view showing the configuration near the plate fin of the cooling device according to the first modification of the first embodiment of the present disclosure. [Figure 5] It is a plan view of the cooling device according to the second modification of the first embodiment of the present disclosure. [Figure 6] It is a plan view of the cooling device according to the third modification of the first embodiment of the present disclosure. [Figure 7] It is a perspective view of the cooling device according to the fourth modification of the first embodiment of the present disclosure. [Figure 8] It is a perspective view of the pin fin according to the fourth modification of the first embodiment of the present disclosure. [Figure 9] It is a view of the cooling device according to the second embodiment of the present disclosure as seen from the side. [Figure 10] It is an enlarged plan view showing the heat exchanger according to the second embodiment of the present disclosure. [Figure 11] It is a view of the cooling device according to the first modification of the second embodiment of the present disclosure as seen from the side. [Figure 12] It is an enlarged perspective view of the heat exchanger according to the second modification of the second embodiment of the present disclosure. [Figure 13] It is a plan view of the cooling device according to the third embodiment of the present disclosure. [Figure 14] It is a plan view of the cooling device according to the modification of the third embodiment of the present disclosure. [Figure 15] It is a plan view of the cooling device according to the fourth embodiment of the present disclosure. [Figure 16] It is an enlarged plan view showing the arrangement of a plurality of pin fins according to the fourth embodiment of the present disclosure. [Figure 17] It is an enlarged front view showing a plurality of pin fins according to the fourth embodiment of the present disclosure. [Figure 18] It is an enlarged plan view showing the arrangement of a plurality of pin fins according to the first modification of the fourth embodiment of the present disclosure. [Figure 19]An enlarged side view showing a plurality of pin fins according to a second modification of the fourth embodiment of the present disclosure.

Mode for Carrying Out the Invention

[0010] <First Embodiment> Hereinafter, the cooling device 10 according to the first embodiment of the present disclosure will be described with reference to FIGS. 1 to 3. As shown in FIG. 1, the cooling device 10 of the present embodiment is mounted on a cooling system 1 that cools the server 4. FIG. 1 is a schematic diagram showing the overall configuration of the cooling system 1. In the illustrated example, the server 4 is housed in a rack 2 extending in the vertical direction Dv. A plurality of server chassis 3 are inserted into the rack 2. The server chassis 3 is a box-shaped housing. A plurality of these server chassis 3 are arranged in the vertical direction Dv. Further, a plurality of servers 4 are inserted into the server chassis 3. These plurality of servers 4 are inserted horizontally side by side.

[0011] The server 4 has a server casing 4a, a server board 4b, and chips (heat generating bodies) 4c such as a CPU and a GPU. The server casing 4a is a rectangular parallelepiped housing extending in the horizontal direction. The server board 4b is housed inside the server casing 4a. The chip 4c is mounted on the server board 4b. Since the chip 4c generates heat during operation, a cooling system 1 for cooling the chip 4c is introduced.

[0012] (Configuration of Cooling System) The cooling system 1 comprises a cooling device 10, a heat exchanger 5, a pump 6, and a control unit 7. A cooling device 10 is installed for each chip 4c. The cooling device 10 is supplied with a refrigerant F. This refrigerant F is, for example, an HFC (Hydro Fluorocarbon) or HFO (Hydro Fluoro Olefin) type refrigerant, or water. The cooling device 10 is a cold plate that cools the chip 4c by performing heat exchange between the refrigerant F and the chip 4c. In this embodiment, the cooling device 10 cools the high-heat generating chip 4c by boiling the refrigerant F. The cooling device 10 is connected to the heat exchanger 5 and the pump 6 by refrigerant pipes 8. The refrigerant F, heated by heat exchange with the chip 4c in the cooling device 10, is sent to the heat exchanger 5 through the refrigerant pipes 8. The heat exchanger 5 is a so-called condenser. The heat exchanger 5 cools the refrigerant F and condenses the gaseous refrigerant F into liquid refrigerant F. The refrigerant F cooled in the heat exchanger 5 is sent to the pump 6 through the refrigerant pipe 8. The pump 6 pumps the refrigerant F again towards the cooling device 10. The refrigerant F pumped to the cooling device 10 exchanges heat with each chip 4c again, cooling each chip 4c. The various components of the cooling system 1, such as the cooling device 10, heat exchanger 5, and pump 6, are controlled by the control unit 7.

[0013] In Figure 1, an example is shown where each server 4 is equipped with three chips 4c and three cooling devices 10. However, the number of chips 4c and cooling devices 10 can be changed as appropriate. For example, each server 4 could be equipped with approximately eight chips 4c and eight cooling devices 10.

[0014] (Cooling system configuration) The configuration of the cooling device 10 will be described below. As shown in Figures 2 and 3, the cooling device 10 comprises a casing 11, a heat exchanger 20, a supply pipe (supply section) 30, and a discharge pipe (discharge section) 40.

[0015] In the following, one predetermined direction intersecting the vertical direction Dv will be referred to as the first direction D1, and the direction intersecting both 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. Furthermore, the first direction D1 and the second direction D2 are orthogonal to each other.

[0016] (Casing) The casing 11 is formed in a hollow shape from a material with excellent thermal conductivity, such as metal. The outer shape of the casing 11 is formed in a rectangular parallelepiped shape, as if it has been flattened horizontally. In a plan view in the vertical direction Dv, the four corners 11a of the casing 11 are formed in a curved shape that protrudes outward, as if chamfered. In a plan view in the vertical direction Dv, the outer edge of the casing 11 is formed to be approximately the same size as the outer edge of the heating element.

[0017] The casing 11 described above can be designed to any dimensions. For example, in this embodiment, the casing 11 is formed in a square shape when viewed in the vertical direction Dv. The height H1 of the casing 11 in the vertical direction Dv is, for example, about 10 mm, and the width W1 in the first direction D1 and the width L1 in the second direction D2 of the casing 11 are, for example, about 55 mm. The casing 11 may be formed in a rectangular shape, shorter in the second direction D2 compared to the first direction D1. In this case, for example, the width L1 of the casing 11 in the second direction D2 may be about 30 mm.

[0018] The casing 11 has a bottom plate 12, a top plate 13, and side plates 14. The base plate 12 is placed on the chip 4c. The base plate 12 extends horizontally. The top plate 13 is positioned above the bottom plate 12 and faces the bottom plate 12 in the vertical direction Dv. The top plate 13 extends horizontally.

[0019] The side panels 14 connect the bottom panel 12 and the top panel 13 on their outer edges. Four side panels 14 are arranged between the bottom panel 12 and the top panel 13. The four side panels 14 include two first side panels 14a facing the first direction D1 and two second side panels 14b facing the second direction D2. The first side panels 14a extend in the second direction D2, and the second side panels 14b extend in the first direction D1. In addition, each side panel 14 is arranged perpendicular to the top panel 13 and the bottom panel 12.

[0020] (heat exchanger) The heat exchanger 20 is provided on the bottom plate 12 within the casing 11. More specifically, the heat exchanger 20 is positioned in a location that overlaps with the region containing the center of gravity of the casing 11 (hereinafter, this region may be referred to as the central region Ac) in a vertical view Dv plane. In this embodiment, the center of gravity of the heat exchanger 20 is positioned to overlap with the center of gravity of the casing 11 in a vertical view Dv plane. Hereinafter, the region within the casing 11 in which the heat exchanger 20 is formed will be referred to as the heat exchange region A1. The heat exchange region A1 includes the central region Ac of the casing 11 in a vertical view Dv plane. The heat exchanger 20 forms an outer peripheral passage 15 between itself and the side plate 14 of the casing 11. The outer peripheral passage 15 is formed in a rectangular frame shape when viewed from the vertical direction Dv. Furthermore, the refrigerant F can flow through the inside of the heat exchanger 20. Details of the configuration of the heat exchanger 20 will be described later.

[0021] (supply pipe) The supply pipe 30 is connected from outside the casing 11 to a first side plate 14a, one of the multiple side plates 14 that make up the casing 11. The supply pipe 30 is a circular pipe having a supply opening 31 that is connected to the side plate 14 and communicates with the inside of the casing 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. The supply pipe 30 is connected to the pump 6 via the refrigerant pipe 8 and supplies refrigerant F from outside the casing 11 to the outer peripheral passage 15.

[0022] (Exhaust pipe) The discharge pipe 40 is connected from outside the casing 11 to the top plate 13 that constitutes the casing 11. More specifically, the discharge pipe 40 is connected to a region of the top plate 13 that overlaps with the heat exchanger 20 in a plan view in the vertical direction Dv. The discharge pipe 40 is a circular pipe having a discharge opening 41 that is connected to the top plate 13 and communicates with the inside of the casing 11. The discharge opening 41 opens in the vertical direction Dv. The center of the discharge opening 41 is located at a position that overlaps with the central part Ac of the casing 11 in the vertical direction Dv in a plan view in the vertical direction Dv. In this embodiment, the center of the discharge opening 41 is located at a position that overlaps with the center of gravity of the casing 11 in the vertical direction Dv within the central part Ac. Therefore, the discharge opening 41 overlaps with the heat exchanger 20 in the vertical direction Dv. The discharge pipe 40 is connected to the heat exchanger 5 via the refrigerant pipe 8 and discharges the refrigerant F from inside the casing 11 to the outside.

[0023] (Configuration of the heat exchanger) The heat exchanger 20 in this embodiment has a partition portion 21 and plate fins 22.

[0024] (Partition section) In this embodiment, the partition portion 21 is formed in a rectangular frame shape so as to surround the discharge pipe 40 in a vertical Dv plan view using a material with excellent thermal conductivity such as metal. More specifically, in a vertical Dv plan view, the four corners 21c of the partition portion 21 are formed in a curved shape that protrudes outward, as if chamfered. That is, the corners 21c of the partition portion 21 are formed in the same shape as the corners 11a of the casing 11.

[0025] The partition section 21 has a first partition wall 21a and a second partition wall 21b. The first partition wall 21a is formed in the shape of a plate extending in the second direction D2 and is provided in a pair spaced apart in the first direction D1. The second partition wall 21b is formed in the shape of a plate extending in the first direction D1 and is provided in a pair spaced apart in the second direction D2. The pair of second partition walls 21b each connect the ends of the first partition wall 21a in the second direction D2. The second partition wall 21b has an inlet 23 that penetrates the second partition wall 21b in the second direction D2. The inlet 23 extends in the first direction D1. The lower edge of the inlet 23 is in contact with the bottom plate 12. On the other hand, the upper edge of the inlet 23 is located below the top plate 13.

[0026] The partition section 21, with its first partition wall 21a on the supply pipe 30 side, blocks the flow of the refrigerant F supplied from the supply pipe 30 in the first direction D1, and branches the flow of the refrigerant F to both sides in the second direction D2. In this embodiment, the partition 21 connects the bottom plate 12 and the top plate 13.

[0027] (Flat fins) Multiple plate fins 22 are provided inside the partition portion 21, arranged in a first direction D1. Each plate fin 22 is a rectangular plate-shaped member extending in a second direction D2. The plate fins 22 are made of a material with excellent thermal conductivity, such as metal. In this embodiment, the plate fins 22 are made of copper. Therefore, the surface temperature of the plate fins 22 is uniform. The plate fins 22 extend upward from the bottom plate 12. The upper edge of the plate fins 22 is spaced apart from the top plate 13, and a predetermined clearance C1 is provided between the plate fins 22 and the top plate 13. The plate fins 22 may be formed to a height similar to that of the partition portion 21. In addition, each plate fin 22 is arranged in a position perpendicular to the bottom plate 12.

[0028] Multiple plate fins 22 are arranged to face the second direction D2. Each pair of plate fins 22 facing the second direction D2 runs along the second partition wall 21b, and each plate fin 22 extends from the second partition wall 21b in the second direction D2. In a side view in the second direction D2, the entirety of the multiple plate fins 22 is located inside the inlet 23 of the partition 21.

[0029] These multiple plate fins 22 create narrow gaps S1 between them that create resistance to the flow of the refrigerant F. These gaps S1 between the plate fins 22 are in communication with the inlet 23 of the partition 21. 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 fins 22 is, for example, about 0.5 mm, and the height H2 of the plate fins 22 is, for example, 5.0 mm.

[0030] (Effects and Benefits) Next, we will explain the effects of the cooling device 10 described above. First, let's explain the flow of the refrigerant F within the cooling device 10. The refrigerant F supplied into the casing 11 from the supply pipe 30 flows into the outer peripheral passage 15. As a result, the refrigerant F branches to both sides of the second direction D2 via the outer peripheral passage 15 and flows around the heat exchanger 20. Subsequently, 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 passes between the plate fins 22 and flows from the outer peripheral side to the central Ac side in a plan view. At this time, all of the plate fins 22 are submerged in the refrigerant F. The refrigerant F exchanges heat with the chip 4c via the plate fins 22 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 boils and evaporates due to the heat of the chip 4c, changing from liquid phase refrigerant F to gaseous phase refrigerant F. The heated refrigerant F is discharged directly outside the casing 11 from the heat exchanger 20 via the discharge pipe 40.

[0031] In this embodiment, the cooling device 10 comprises a casing 11, a heat exchanger 20, a supply pipe 30, and a discharge pipe 40. The casing 11 has a bottom plate 12, a top plate 13, and side plates 14. The casing 11 is hollow. The heat exchanger 20 is provided on the bottom plate 12 inside the casing 11. The heat exchanger 20 forms an outer peripheral passage 15 between itself and the side plates 14 of the casing 11, and the refrigerant F is allowed to flow through its interior. The supply pipe 30 supplies the refrigerant F to the outer peripheral passage 15 from the outside. The discharge pipe 40 is connected to a region on the top plate 13 that overlaps with the heat exchanger 20 in a plan view, and discharges the refrigerant F from inside the casing 11 to the outside.

[0032] According to this embodiment, the refrigerant F supplied from the supply pipe 30 into the casing 11 is supplied to the inside of the heat exchanger 20 through the outer peripheral passage 15. As the refrigerant F passes through the outer peripheral passage 15, a pressure loss occurs in the refrigerant F, which prevents an excessive increase in the flow velocity of the refrigerant F. As a result, the refrigerant F is supplied evenly into the casing 11. Therefore, the refrigerant F can be stably supplied to the entire casing 11. Furthermore, the refrigerant F that flows into the inside of the heat exchanger 20 is heated by heat exchange in the heat exchanger 20 and then directly discharged from the heat exchanger 20 to the discharge pipe 40. As a result, the refrigerant F after heat exchange is smoothly discharged from the casing 11. This prevents the refrigerant F after heat exchange from accumulating inside the casing 11, thereby improving cooling efficiency. Furthermore, because the pressure loss is high, the refrigerant F can be supplied evenly within the casing 11 without requiring a complicated control system that finely adjusts the flow rate of the refrigerant F by installing a valve for each casing 11 (for each heating element), as in conventional systems.

[0033] In this embodiment, the heat exchanger 20 has a plurality of plate fins 22 arranged in a first direction D1, and each plate fin 22 extends in a second direction D2.

[0034] As a result, the refrigerant F supplied from the supply pipe 30 into the casing 11 is supplied between the multiple plate fins 22 through the outer peripheral passage 15. Subsequently, the refrigerant F flows between the plate fins 22. Pressure loss occurs in the refrigerant F as it passes between the plate fins 22, further suppressing an excessive increase in the flow velocity of the refrigerant F. Therefore, the refrigerant F is supplied more evenly within the casing 11. Furthermore, the plate fins 22 increase the surface area (hereinafter referred to as the heat transfer area) of the heat exchanger 20 that performs heat exchange, thereby further improving the cooling efficiency.

[0035] Furthermore, the flow resistance can be adjusted to an appropriate size by simply changing the thickness T1 of the plate fins 22 or the pitch P1 of the multiple plate fins 22.

[0036] In this embodiment, the partition portion 21 is assumed to be formed in a rectangular shape in a plan view in the vertical direction Dv so as to surround a plurality of plate fins 22, but this is not limited to this. The partition portion 21 may consist only of a pair of first partition walls 21a extending in the second direction D2. Alternatively, instead of the first partition walls 21a, plate fins 22 with the same length in the second direction D2 as the first partition walls 21a may be provided.

[0037] In this embodiment, the second partition wall 21b is provided with an inlet 23 extending in the first direction D1, but it is not limited to this. Instead of the inlet 23, the second partition wall 21b may be provided with a slit extending in the vertical direction Dv, or with a circular or polygonal fine through-hole, etc.

[0038] 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 it is not limited to this. The partition 21 may be formed to extend upward from the bottom plate 12 and be spaced downward from the top plate 13. In this case, it is necessary to adjust the flow rate of the refrigerant F supplied from the supply pipe 30 so that all of the refrigerant F is evaporated within the casing 11, so that the refrigerant F is not discharged from the discharge pipe 40 without coming into contact with the heat exchanger 20. In this case, the partition 21 becomes smaller, which makes the cooling device 10 lighter and reduces manufacturing costs.

[0039] <First modified example of the first embodiment> Next, with reference to Figure 4, a first modified example of the first embodiment will be described. As shown in Figure 4, in this modified example, the heat exchanger 20 has a plurality of bead-shaped (spherical) particles 24 between the plate fins 22. The particles 24 are made of, for example, metal, resin, polymer, etc. The diameter of the particles 24 is, for example, several μm to about 1 mm.

[0040] In this case, it is necessary to allow the refrigerant F to flow between the plate fins 22 while preventing the particles 24 from flowing out of the plate fins 22. In this embodiment, for example, a second partition wall 21b provided at the outer end of the plate fin 22 in the second direction D2 has multiple slits 23A, which are narrower than the diameter of the particles 24, instead of an inlet 23. The slits 23A extend, for example, in the vertical direction Dv. Furthermore, a closure plate (not shown) is provided at the inner end of the plate fin 22 in the second direction D2, with multiple similar slits 23A formed therein.

[0041] Thus, in this modified configuration, the particles 24 within the plate fins 22 move due to the flow of the refrigerant F and the buoyancy generated by the boiling of the refrigerant F, causing the refrigerant F to be agitated. This allows the refrigerant F to perform heat exchange uniformly.

[0042] Furthermore, fine gaps are formed between the multiple particles 24 through which the refrigerant F can flow. The refrigerant F rises while being dispersed through these gaps between the multiple particles 24. In addition, the multiple particles 24 move within the heat exchange due to the flow of the refrigerant F and the lift generated when the refrigerant F boils. This makes it difficult for the bubbles produced by the boiling of the refrigerant F to coalesce. Therefore, the transition point from nucleation boiling to film boiling can be shifted to the high heat flux side (high temperature side). Thus, the transition from nucleation boiling to film boiling can be suppressed with a simple configuration that only involves arranging multiple particles 24.

[0043] Furthermore, these multiple particles 24 may be given the function of absorbing impurities such as dirt, moisture, and oil. This allows the cooling device 10 to purify the refrigerant F flowing through the heat exchanger 20. As a result, heat exchange between the refrigerant F and the chip 4c is promoted, and the cooling efficiency can be further improved. Methods for imparting the function of absorbing impurities to multiple particles 24 include forming the particles 24 with a specific adsorbent, and increasing the density of the particles 24 so that impurities are trapped in the gaps between the particles 24.

[0044] In this modification, instead of multiple particles 24, porous sections through which the refrigerant F can flow may be placed in the gaps between the plate fins 22.

[0045] <Second variation of the first embodiment> Next, a second modified example of the first embodiment will be described with reference to Figure 5. As shown in Figure 5, each plate fin 22 extends across the entire second direction D2 of the heat exchanger 20. Therefore, the plate fins 22 are located in the central part Ac of the casing 11 and overlap with the discharge opening 41 in the vertical direction Dv. In this modified example, the partition portion 21 may not be provided.

[0046] Thus, in this modified configuration, the length of each plate fin 22 is increased, which increases the heat transfer area and improves cooling efficiency.

[0047] <Third Modification of the First Embodiment> Next, a third modified example of the first embodiment will be described with reference to Figure 6. As shown in Figure 6, the plate fin 22 may be formed in a wave shape so as to extend in a zigzag pattern in the second direction D2 when viewed from above.

[0048] This allows for a further increase in the heat transfer area, thereby improving cooling efficiency even more.

[0049] <Fourth modified example of the first embodiment> Next, a fourth modified example of the first embodiment will be described with reference to Figures 7 and 8. As shown in Figure 7, the heat exchanger 20 is positioned to overlap with the discharge opening 41 of the discharge pipe 40 in a plan view in the vertical direction Dv, and further has pin fins 50 extending in the vertical direction Dv. Multiple pin fins 50 are formed on the bottom plate 12. The region where the pin fins 50 are formed (hereinafter referred to as the pin fin region A2) extends in the first direction D1. The pin fin region A2 is provided between sets of multiple plate fins 22 spaced apart in the second direction D2. That is, these multiple pin fins 50 are sandwiched in the second direction D2 by sets of multiple plate fins 22 spaced apart in the second direction D2.

[0050] Each pin fin 50 is formed in a circular shape when viewed in a plan view in the vertical direction Dv. Furthermore, as shown in Figure 8, the pin fin 50 is shaped to taper upwards from the base where it connects to the bottom plate 12. That is, the pin fin 50 is formed in a shape where the horizontal diameter gradually narrows in the vertical direction Dv from the base on the bottom plate 12 side. More specifically, the pin fin 50 is a conical member and is shaped like a teardrop when viewed from the side in the horizontal direction. The pin fin 50 is made of a material with excellent thermal conductivity, such as metal.

[0051] Thus, in this modified configuration, the heat exchanger 20 is positioned to overlap with the discharge opening 41 of the discharge pipe 40 in a plan view in the vertical direction Dv, and further has pin fins 50 extending in the vertical direction Dv. The pin fins 50 are sandwiched in the second direction D2 by a plurality of plate fins 22 and are shaped to taper upwards.

[0052] As a result, the refrigerant F passes between the plate fins 22 and then exchanges heat with the pin fins 50. The pin fins 50 are shaped to taper towards the top, which increases the heat transfer area. Furthermore, in the region where the pin fins 50 are formed, the flow resistance decreases towards the top. This allows the refrigerant F to be discharged to the outside more smoothly. In particular, when the refrigerant F boils and vaporizes inside the casing 11, the gaseous refrigerant F can be discharged to the outside more smoothly. In this way, by improving heat transfer performance while smoothly discharging the refrigerant F from the exhaust pipe 40 located at the top, the cooling performance can be further improved.

[0053] <Second Embodiment> Hereinafter, the cooling device 210 according to the second embodiment of this disclosure will be described with reference to Figures 9 and 10. For components of the second embodiment that are common to the first embodiment, the same names, reference numerals, etc., will be used, and their descriptions will be omitted as appropriate. As shown in Figures 9 and 10, in this embodiment, the heat exchanger 220 has a partition portion 21, a grid fin 60, and pin fins 250.

[0054] (Partition section) Multiple through-holes 26 are formed around the entire circumference of the partition 21. The through-holes 26 are formed, for example, in a circular shape. The shape of the through-holes 26 can be changed as appropriate. The refrigerant F supplied into the casing 11 from the supply pipe 30 flows into the heat exchanger 220 from all sides through the multiple through-holes 26.

[0055] (Lattice fins) The grid fins 60 extend horizontally so as to intersect the vertical direction Dv. Each grid 63 of the grid fins 60 is formed in a square shape by combining a first pole 61 extending in a first direction D1 and a second pole 62 extending in a second direction D2. Here, the shortest width between the inner edges of the grid 63 is referred to as the "grid diameter R1". In this embodiment, since the grid 63 is formed in a square shape, the length of one side of the grid 63 is the grid diameter R1.

[0056] The first pole 61 and the second pole 62 are both formed in a cylindrical shape. The shapes of the first pole 61 and the second pole 62 can be changed as appropriate. For example, the first pole 61 and the second pole 62 may both be formed in a rectangular prism shape.

[0057] Multiple grid fins 60 are arranged in the vertical direction Dv at equal intervals. Hereafter, the pitch of the multiple grid fins 60 will be referred to as the first pitch P2. Furthermore, adjacent grid fins 60 are offset from each other in a direction that intersects the vertical direction Dv (the horizontal direction in this embodiment). The multiple grid fins 60 include a first grid fin 60a and a second grid fin 60b. The first grid fin 60a and the second grid fin 60b are arranged alternately in the vertical direction Dv. The first grid fin 60a and the second grid fin 60b are arranged in an alternating pattern. Therefore, in a plan view in the vertical direction Dv, the grid points 64 of the second grid fin 60b are located at the center of the grid 63 of the first grid fin 60a. The first grid fins 60a are arranged at the same horizontal position, and the second grid fins 60b are arranged at the same horizontal position.

[0058] In the illustrated example, two stages of the first grid fin 60a and one stage of the second grid fin 60b are provided, but this is not limited to this configuration. The number of stages of the first grid fin 60a and the number of stages of the second grid fin 60b can be changed as appropriate. Furthermore, a predetermined clearance C1 is provided between the uppermost of the multiple grid fins 60 and the top plate 13.

[0059] (Pinfin) The pin fins 250 are supports that extend in the vertical direction Dv and support the grid fins 60. In a plan view in the vertical direction Dv, the pin fins 250 are arranged in a grid pattern in the first direction D1 and the second direction D2. Here, 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 alternately. Therefore, the multiple pin fins 250 that make up a pair 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 alternately. Therefore, the multiple pin fins 250 that make up a pair of adjacent second pin rows 252 are arranged in a zigzag pattern extending in the second direction D2.

[0060] Furthermore, the pitch between the pin fins 250 constituting the second pin row 252 is narrower than the pitch between the pin fins 250 constituting the first pin row 251. Hereafter, the pitch between the pin fins 250 constituting the second pin row 252 will be referred to as the second pitch P3. Furthermore, 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 becomes the second pitch P3.

[0061] Each pin fin 250 is perpendicular to the grid fins 60. In this embodiment, the pin fins 250 are formed in a cylindrical shape. The shape of the pin fins 250 can be changed as appropriate. For example, the pin fins 250 may be formed in a rectangular prism shape.

[0062] Next, we will explain the dimensions of the lattice fins 60 and pin fins 250 mentioned above. The grid diameter R1 and first pitch P2 of the grid fins 60, and the second pitch P3 of the pin fins 250 are preferably both several tens of micrometers or more. For example, the grid diameter R1 is designed to be 300 μm, the first pitch P2 to be 150 μm, and the second pitch P3 to be 0.45 mm or more and 0.6 mm or less. Also, the height H3 of the pin fins 250 in the vertical direction Dv is designed to be, for example, 3 mm. The dimensions of the grid fins 60 and pin fins 250 can be changed as appropriate.

[0063] (Effects and Benefits) Next, we will explain the effects of the cooling device 210 described above.

[0064] In this embodiment, the heat exchanger 220 extends horizontally and has a plurality of grid fins 60 arranged in the vertical direction Dv. Adjacent grid fins 60 are arranged with a horizontal offset from each other.

[0065] As a result, the bubbles generated when the refrigerant F boils due to heat exchange are divided by the grid fins 60 as they rise. Therefore, it is possible to prevent the bubbles from coalescing and delay the generation of critical heat flux. Furthermore, the lattice fins 60 increase the heat transfer area, thereby improving cooling efficiency.

[0066] In this embodiment, the system further includes pin fins 250 that extend in the vertical direction Dv and support a plurality of grid fins 60.

[0067] As a result, the refrigerant F can exchange heat with the grid fins 60 and pin fins 250, increasing the heat transfer area. Therefore, the cooling efficiency can be further improved.

[0068] In this embodiment, a clearance C1 is provided between the uppermost of the multiple grid fins 60 and the top plate 13. This widens the upper region of the heat exchanger 220, increasing the upward opening ratio of the heat exchanger 220. As a result, bubbles generated when the refrigerant F boils can easily detach from the heat exchanger 220. Therefore, the gaseous refrigerant F inside the casing 11 can be smoothly discharged from the discharge pipe 40.

[0069] Furthermore, when the refrigerant F is heated by the heat exchanger 220, a portion of the refrigerant F evaporates, creating a gas-liquid two-phase state inside the casing 11. As a result, the gas-liquid interface prevents the liquid phase refrigerant F from moving above the grid fins 60. Therefore, in principle, the liquid phase refrigerant F comes into contact with the grid fins 60, performs heat exchange, and is then discharged outside the casing 11.

[0070] In this embodiment, the refrigerant F flowing into the casing 11 from the supply pipe 30 flows into the heat exchanger 220 from a single point, but this is not limited to this. For example, a sub-header (not shown) communicating with the supply opening 31 of the supply pipe 30 may be provided inside the casing 11, and the refrigerant F may be branched from multiple points and flowed into the heat exchanger 220.

[0071] In this embodiment, the arrangement of the grid fins 60 and the first pin row 251 and the second pin row 252 can be changed as appropriate. For example, the grid fins 60 and the first pin row 251 and the second pin row 252 may be inclined with respect to the first direction D1 and the second direction D2 in a plan view in the vertical direction Dv.

[0072] In this embodiment, the case in which the grid fins 60 are supported by pin fins 250 has been described, but it is not limited to this. The grid fins 60 may also be supported by partition portions 21 provided on the outer circumference. In this case, pin fins 250 may not be provided.

[0073] In this embodiment, the partition portion 21 does not necessarily have to be provided to connect the bottom plate 12 and the top plate 13. For example, the partition portion 21 may extend from the bottom plate 12, and its upper end may be spaced downward from the top plate 13. Also, a partition portion 21 surrounding the lattice fins 60 from the outer periphery may not be provided.

[0074] In this embodiment, the grid 63 of the grid fin 60 is assumed to be formed in a square shape, but it is not limited to this. The grid 63 of the grid fin 60 may be formed in a rectangular, polygonal, or circular shape, for example.

[0075] <First modified example of the second embodiment> Next, with reference to Figure 11, a first modified example of the second embodiment will be described. As shown in Figure 11, in this modified example, the grid fins 60 are laid across the entire horizontal area inside the casing 11. Therefore, in this modified example, the heat transfer area can be further increased. Consequently, the cooling efficiency can be further increased.

[0076] In this modified example, the grid fins 60 may be supported by the side plates 14 of the casing 11. In this case, the pin fins 250 that support the grid fins 60 may not be provided.

[0077] <Second modified example of the second embodiment> Next, a second modified example of the second embodiment will be described with reference to Figure 12. As shown in Figure 12, in this modified example, the pin fins 250A supporting the lattice fins 60 are formed in a shape similar to the pin fins 50 in the fourth modified example of the first embodiment. That is, the pin fins 250A are formed in a shape that tapers towards the top.

[0078] This allows for an even greater increase in the heat transfer area. Furthermore, in the region where the pin fins 250A are formed, the flow resistance decreases towards the upper side. This makes it possible to smoothly discharge the refrigerant F to the outside. In particular, when the refrigerant F boils and vaporizes inside the casing 11, the gaseous refrigerant F can be discharged to the outside more smoothly. Therefore, by further improving heat transfer performance and smoothly discharging the refrigerant F from the exhaust pipe 40 located at the top, cooling performance can be further improved.

[0079] <Third Embodiment> Hereinafter, the cooling device 310 according to the third embodiment of this disclosure will be described with reference to Figure 13. For configurations of the third embodiment that are common to the above embodiments, the same names, reference numerals, etc., will be used, and their descriptions will be omitted as appropriate. As shown in Figure 13, in this embodiment, the cooling device 310 further includes a porous section 27 through which the refrigerant F can flow.

[0080] The heat exchanger 320 has a porous portion 27 instead of the multiple plate fins 22 in the first embodiment.

[0081] The porous sections 27 are provided in pairs, spaced apart in the second direction D2. Each porous section 27 extends in the first direction D1. The porous sections 27 have numerous pores (not shown) through which the refrigerant F can flow. These porous sections 27 act as flow resistance, causing pressure loss.

[0082] (Effects and Benefits) Next, we will explain the effects of the cooling device 310 described above. In this embodiment, the heat exchanger 320 has a porous portion 27 through which the refrigerant F can pass.

[0083] This allows for pressure loss to be generated with a simple configuration that only requires the provision of a porous section 27, enabling the refrigerant F to be supplied evenly within the casing 11. Therefore, the refrigerant F can be stably supplied throughout the casing 11, improving cooling efficiency. When the refrigerant F boils due to heat exchange, the bubbles generated disperse as they pass through the porous section 27. Therefore, the coalescence of the bubbles is suppressed, and the generation of critical heat flux can be delayed. Furthermore, the porous section 27 can capture and absorb dirt, moisture, and oil contained in the refrigerant F through its internal pores.

[0084] <Modified form of the third embodiment> Next, a modified example of the third embodiment will be described with reference to Figure 14. As shown in Figure 14, in this modified example, the heat exchanger 320 has pin fins 350 extending in the vertical direction Dv at a position (pin fin region A2) that overlaps with the discharge opening of the discharge pipe in a plan view in the vertical direction Dv. Multiple pin fins 350 are provided within the pin fin region A2. These multiple pin fins 350 are sandwiched in the second direction D2 by a pair of porous portions 27 that are spaced apart in the second direction D2. Furthermore, the pin fin 350 is formed in a shape similar to the pin fin 50 of the fourth modification of the first embodiment. That is, the pin fin 350 is formed in a shape that tapers towards the top.

[0085] As a result, the refrigerant F passes through the porous section 27 and then exchanges heat with the pin fins 350. Furthermore, the pin fins 350 are shaped to taper towards the top, thus increasing the heat transfer area. Additionally, in the region where the pin fins 350 are formed, the flow resistance decreases towards the top. Therefore, the refrigerant F can be smoothly discharged to the outside. Thus, the cooling efficiency can be further improved.

[0086] <Fourth Embodiment> Hereinafter, the cooling device 410 according to the fourth embodiment of this disclosure will be described with reference to Figures 15 to 17. For configurations of the fourth embodiment that are common to the above embodiments, the same names, reference numerals, etc., will be used, and their descriptions will be omitted as appropriate. As shown in Figure 15, in this embodiment, the heat exchanger 420 has a plurality of pin fins 450 provided along the outer peripheral passage 15. Figure 15 schematically illustrates the arrangement of the pin fins 450. Each pin fin 450 extends in the vertical direction Dv. In this embodiment, the pin fin region A2, where multiple pin fins 450 are formed, is arranged in an annular shape so as to surround the center of the casing 11 from the outer periphery in a plan view in the vertical direction Dv. In this embodiment, the multiple pin fins 450 form an outer periphery passage 15 within the casing 11, and no partition portion 21 is provided as in the first embodiment. However, a partition portion 21 may be provided, in which case the partition portion 21 must have through holes, such as the through holes 26 in the second embodiment, around its entire circumference. Here, using the region of the pin fin region A2 located on one side of the second direction D2 relative to the central part Ac (hereinafter referred to as representative region A3) as an example, the arrangement and shape of the pin fins 450 will be explained in detail with reference to Figures 16 and 17.

[0087] As shown in Figures 16 and 17, the pin fins 450 are formed in a cylindrical shape extending in the vertical direction Dv. The pin fins 450 are arranged at equal intervals in one direction in the horizontal plane, forming a linear pin row 451 in a view in the vertical direction Dv. Furthermore, multiple pin rows 451 are provided at equal intervals in a direction that intersects (orthogonal to) the direction in which the pin row 451 extends in the horizontal direction. In representative region A3, the pin row 451 is formed linearly in the second direction, and the pin row 451 is arranged at equal intervals in the first direction D1. In addition, between two adjacent rows of pin rows 451, the pin fins 450 are arranged in a zigzag pattern so as to be staggered.

[0088] The dimensions of the pin fin 450 and the pitch P4 between the pin fins 450 can be changed as appropriate. For example, if the diameter of the pin fin 450 is 300 μm and the height H4 of the pin fin 450 is 3 mm, the pitch P4 between the pin fins 450 constituting the pin row 451 is set to be between 0.45 mm and 0.60 mm. For example, if the diameter of the pin fin 450 is 500 μm and the height H4 of the pin fin 450 is 5 mm, the pitch P4 between the pin fins 450 constituting the pin row 451 is set to be between 1 mm and 0.75 mm. For example, if the diameter of the pin fin 450 is 1000 μm and the height H4 of the pin fin 450 is 10 mm, the pitch P4 between the pin fins 450 constituting the pin row 451 will be set to 1.5 mm or more and 2 mm or less.

[0089] (Effects and Benefits) Next, we will explain the effects of the cooling device 410 described above. In this embodiment, the heat exchanger 420 extends in the vertical direction Dv and has a plurality of pin fins 450 provided along the outer peripheral passage 15.

[0090] As a result, the refrigerant F is supplied to the inside of the heat exchanger 420 by passing between the pin fins 450. Since pressure loss occurs in the refrigerant F as it passes between the pin fins 450, an excessive increase in the flow velocity of the refrigerant F is further suppressed. Therefore, the refrigerant F is supplied more evenly to the heat exchanger 420. Thus, with a relatively simple configuration of providing pin fins 450, the refrigerant F can be supplied evenly into the casing 11.

[0091] Furthermore, the manufacturing efficiency of these multiple pin fins 450 can be improved by manufacturing them using, for example, additive manufacturing (AM) techniques.

[0092] (First modified example of the fourth embodiment) Next, with reference to Figure 18, a first modified example of the fourth embodiment will be described. As shown in Figure 18, in this modified example, the pitch P4 between the multiple pin fins 450 increases as you move horizontally toward the discharge opening 41 side of the discharge pipe 40.

[0093] For example, if the diameter of the pin fin 450 is 300 μm and the height H4 of the pin fin 450 is 3 mm, the pitch P4 between the pin fins 450 that make up the pin row 451 will be 0.6 mm at the upstream end and 1.8 mm at the downstream end.

[0094] Incidentally, when the refrigerant F boils in the casing 11 and exists in a gas-liquid two-phase state, the proportion of gaseous refrigerant F increases as the flow direction of the refrigerant F moves downstream. In this modified example, the pitch P4 between the multiple pin fins 450 increases as the flow direction moves downstream, making it easier for gaseous refrigerant F to flow downstream. Therefore, a rapid increase in the pressure of gaseous refrigerant F downstream can be suppressed. Thus, gaseous refrigerant F can be discharged smoothly.

[0095] Furthermore, the area near the discharge opening 41 (for example, in a vertical Dv plan view, from the center of the discharge opening 41 to about 0.5 to 5 times the diameter of the discharge opening 41) does not necessarily need to have pin fins 450 formed thereon.

[0096] (Second modified example of the fourth embodiment) Next, with reference to Figure 19, a second modified example of the fourth embodiment will be described. As shown in Figure 19, in this modified example, in addition to the pitch change between the pin fins 450 as in the first modified example, pin fins 450 with a lower height H4 are arranged as you move downstream in the flow direction of the refrigerant F. For example, at the upstream end, the height H4 of the pin fin 450 is 3 mm, but from there, progressively lower pin fins 450 are placed, and at the downstream end, the height H4 of the pin fin 450 is 1 mm.

[0097] According to this modified configuration, the pin fins 450 with a height H4 decrease as you move downstream, allowing the gaseous refrigerant F to flow more easily downstream. Therefore, a rapid increase in the pressure of the gaseous refrigerant F downstream can be suppressed.

[0098] (Other embodiments) Although embodiments of this disclosure have 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. It is also possible to combine the above-described embodiments and their respective modifications as appropriate.

[0099] In the above embodiment, the cooling devices 10, 210, 310, and 410 were described as cold plates for cooling chips 4c such as CPUs and GPUs mounted on the server 4, but the embodiment is not limited to this. The cooling devices 10, 210, 310, and 410 may also be used to cool heat-generating elements other than chips 4c.

[0100] In the above embodiment, the case in which the cooling devices 10, 210, 310, and 410 boil and evaporate the refrigerant F within the casing 11 has been described, but the embodiment is not limited to this. The refrigerant F does not necessarily need to boil and vaporize during the process of heat exchange with the tip 4c, and may circulate within the cooling system 1 in a liquid phase state.

[0101] In the above embodiment, the case in which the casing 11 is formed in the shape of a rectangular parallelepiped has been described, but it is not limited to this. The casing 11 may be formed in a polygonal shape other than a rectangular parallelepiped, for example, it may be formed in the shape of a disc. Similarly, the shape of the heat exchangers 20, 220, 320, and 420 is not limited to a rectangular parallelepiped, and the shape of the outer peripheral passage 15 is not limited to a rectangular frame. That is, the heat exchangers 20, 220, 320, and 420 may be formed in a polygonal shape other than a rectangular parallelepiped, for example, it may be formed in the shape of a disc. Also, the outer peripheral passage 15 may be formed in a polygonal frame shape other than a rectangle, for example, it may be formed in the shape of a ring.

[0102] In the above embodiment, the supply section is a supply pipe 30 having a supply opening 31, and the discharge section is a discharge pipe 40 having a discharge opening 41, but it is not limited to this. The supply section may consist only of the supply opening 31, and the discharge section may consist 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. Also, the supply opening 31 is said to be connected to the side plate 14, but it is not limited to this. The supply opening 31 may be connected to, for example, the top plate 13 at a position that overlaps with the outer peripheral passage 15 in the vertical direction Dv. Also, the discharge opening 41 is said to be connected to the top plate 13 at the central part Ac of the casing 11, but it is not limited to this. The discharge opening 41 may be located on the outer periphery side of the central part Ac of the casing 11 in a vertical direction Dv plan view, as long as it overlaps with the heat exchangers 20, 220, 320, and 420 in the vertical direction Dv.

[0103] <Note> The cooling devices 10, 210, 310, and 410 described in each embodiment can be understood, for example, as follows.

[0104] (1) The cooling device 10, 210, 310, 410 according to the first embodiment comprises a hollow casing 11 having a bottom plate 12 on which a heating element is placed, a top plate 13 facing the bottom plate 12, and a side plate 14 connecting the bottom plate 12 and the top plate 13 on the outer circumference; heat exchangers 20, 220, 320, 420 provided on the bottom plate 12 within the casing 11, forming an outer peripheral passage 15 between them and the side plate 14 of the casing 11, and through which a refrigerant F can flow; a supply unit for supplying the refrigerant F to the outer peripheral passage 15 from the outside; and a discharge unit connected to a region of the top plate 13 that overlaps with the heat exchangers 20, 220, 320, 420 in a plan view, for discharging the refrigerant F from inside the casing 11 to the outside. An example of a supply section is the supply pipe 30 of the above embodiment, and an example of a discharge section is the discharge pipe 40 of the above embodiment.

[0105] According to this embodiment, the refrigerant F supplied from the supply unit into the casing 11 is supplied to the inside of the heat exchangers 20, 220, 320, and 420 through the outer peripheral passage 15. As the refrigerant F passes through the outer peripheral passage 15, pressure loss occurs in the refrigerant F, which prevents an excessive increase in the flow velocity of the refrigerant F. As a result, the refrigerant F is supplied evenly into the casing 11. Therefore, the refrigerant F can be stably supplied to the entire casing 11. Furthermore, the refrigerant F that flows into the inside of the heat exchangers 20, 220, 320, and 420 is heated by heat exchange in the heat exchangers 20, 220, 320, and 420, and then directly discharged from the heat exchangers 20, 220, 320, and 420 to the discharge unit. As a result, the refrigerant F after heat exchange is smoothly discharged from the casing 11. This prevents the refrigerant F after heat exchange from accumulating inside the casing 11, thereby improving cooling efficiency.

[0106] (2) The cooling device 10 of the second embodiment is the cooling device 10 of (1), wherein the heat exchanger 20 has a plurality of plate fins 22 arranged in a first direction D1 that intersects the vertical direction Dv, and each plate fin 22 may extend in a second direction D2 that intersects the vertical direction Dv and the first direction D1.

[0107] As a result, the refrigerant F supplied from the supply unit into the casing 11 is supplied between the multiple plate fins 22 through the outer peripheral passage 15. The refrigerant F then flows between the plate fins 22. Pressure loss occurs in the refrigerant F as it passes between the plate fins 22, which further suppresses an excessive increase in the flow velocity of the refrigerant F. Therefore, the refrigerant F is supplied more evenly within the casing 11. Furthermore, the plate fins 22 increase the surface area (heat transfer area) of the heat exchanger 20 that performs heat exchange.

[0108] (3) The cooling device 10 of the third embodiment is the cooling device 10 of (2), wherein the heat exchanger 20 is provided in a position that overlaps with the discharge section in a plan view, and further has pin fins 50 extending in the vertical direction Dv, the pin fins 50 may be sandwiched in the second direction D2 by the plurality of plate fins 22, and be formed in a shape that tapers towards the top.

[0109] As a result, the refrigerant F passes between the plate fins 22 and then exchanges heat with the pin fins 50. The pin fins 50 are shaped to taper towards the top, which increases the heat transfer area. Furthermore, in the region where the pin fins 50 are formed, the flow resistance decreases towards the top. This allows the refrigerant F to be discharged smoothly to the outside.

[0110] (4) The cooling device 210 of the fourth embodiment is the cooling device 210 of (1), wherein the heat exchanger 220 extends so as to intersect the vertical direction Dv and has a plurality of grid fins 60 arranged in the vertical direction Dv, and adjacent grid fins 60 may be arranged to be offset from each other in a direction that intersects the vertical direction Dv.

[0111] As a result, the bubbles generated when the refrigerant F boils due to heat exchange are divided by the grid fins 60 as they rise. Therefore, it is possible to prevent the bubbles from coalescing.

[0112] (5) The cooling device 210 of the fifth embodiment comprises a hollow casing 11 having a bottom plate 12 on which a heating element is placed, a top plate 13 facing the bottom plate 12, and a side plate 14 connecting the bottom plate 12 and the top plate 13 on the outer circumference, a heat exchanger 220 provided on the bottom plate 12 inside the casing 11 and through which a refrigerant F can flow, a supply unit for supplying the refrigerant F into the casing 11 from the outside, and a discharge unit connected to a region of the top plate 13 that overlaps with the heat exchanger 220 in a plan view and for discharging the refrigerant F from inside the casing 11 to the outside, wherein the heat exchanger 220 extends so as to intersect the vertical direction Dv and has a plurality of grid fins 60 arranged in the vertical direction Dv, and adjacent grid fins 60 are offset from each other in a direction that intersects the vertical direction Dv.

[0113] (6) The cooling device 210 of the sixth embodiment is the cooling device 210 of (4) or (5), wherein the heat exchanger 220 further comprises pin fins 250, 250A extending in the vertical direction Dv, which support the plurality of grid fins 60.

[0114] As a result, the refrigerant F can exchange heat with the grid fins 60 and the pin fins 250 and 250A, thereby increasing the heat transfer area.

[0115] (7) The cooling device 210 of the seventh embodiment is the cooling device 210 of (6), wherein the pin fins 250A may be formed in a shape that tapers towards the top.

[0116] This allows for an even greater increase in the heat transfer area. Furthermore, in the region where the pin fins 250A are formed, the flow resistance decreases towards the upper side. As a result, the refrigerant F can be smoothly discharged to the outside.

[0117] (8) The cooling device 310 of the eighth embodiment is the cooling device 310 of (1), wherein the heat exchanger 320 may have a porous portion 27 through which the refrigerant F can pass.

[0118] This allows for a simple configuration that only requires the provision of a porous section 27, enabling heat exchange between the porous section 27 and the refrigerant F while simultaneously generating pressure loss and uniformly supplying the refrigerant F into the casing 11. When the refrigerant F boils due to heat exchange, the bubbles generated disperse as they pass through the porous section 27. Therefore, the coalescence of the bubbles can be suppressed. Furthermore, the porous section 27 can absorb dirt, moisture, and oil contained in the refrigerant F.

[0119] (9) The cooling device 310 of the ninth embodiment is the cooling device 310 of (8), wherein the heat exchanger 320 is provided in a position that overlaps with the discharge section in a plan view, and further has pin fins 350 extending in the vertical direction Dv, the pin fins 350 may be sandwiched by the porous section 27 in a direction intersecting the vertical direction Dv, and be formed in a shape that tapers towards the top.

[0120] As a result, the refrigerant F passes through the porous section 27 and then exchanges heat with the pin fins 350. Furthermore, the pin fins 350 are shaped to taper towards the top, thereby increasing the heat transfer area. Additionally, in the region where the pin fins 350 are formed, the flow resistance decreases towards the top. This allows the refrigerant F to be smoothly discharged to the outside.

[0121] (10) The cooling device 410 of the tenth embodiment is the cooling device 410 of (1), wherein the heat exchanger 420 extends in the vertical direction Dv and has a plurality of pin fins 450 provided along the outer peripheral passage 15.

[0122] As a result, the refrigerant F is supplied to the inside of the heat exchanger 420 by passing between the pin fins 450. Since pressure loss occurs in the refrigerant F as it passes between the pin fins 450, an excessive increase in the flow velocity of the refrigerant F is further suppressed. Therefore, the refrigerant F is supplied to the heat exchanger 420 more evenly.

[0123] (11) The cooling device 410 of the eleventh embodiment is the cooling device 410 of (10), wherein the pitch P4 of the pin fins 450 may increase as it moves toward the discharge section in a direction intersecting the vertical direction Dv.

[0124] Incidentally, when the refrigerant F boils in the casing 11 and exists in a gas-liquid two-phase state, the proportion of gaseous refrigerant F increases as the flow direction of the refrigerant F moves downstream. In this embodiment, the pitch P4 between the multiple pin fins 450 increases as the flow direction moves downstream, so that gaseous refrigerant F can flow more easily downstream. Therefore, a rapid increase in the pressure of gaseous refrigerant F downstream can be suppressed.

[0125] (12) The cooling device 410 of the twelfth embodiment is the cooling device 410 of (10) or (11), wherein the pin fins 450 are arranged in a direction that intersects the vertical direction Dv and are directed toward the discharge side, with the height H4 decreasing accordingly.

[0126] According to this embodiment, since the pin fins 450 with a height H4 that decreases towards the downstream side are arranged, the gaseous refrigerant F flows more easily downstream. Therefore, a rapid increase in the pressure of the gaseous refrigerant F downstream can be suppressed, and the gaseous refrigerant F can be discharged smoothly. [Explanation of symbols]

[0127] 1...Cooling system, 2...Rack, 3...Server chassis, 4...Server, 4a...Server casing, 4b...Server board, 4c...Chip (heating 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...First side plate, 14b...Second side plate, 15...Perimeter aisle 20...Heat exchanger, 21...Partition, 21a...First partition, 21b...Second partition, 21c...Corner, 22...Plate fin, 23...Inlet, 23A...Slit, 24...Particle, 26...Through hole, 27...Porous section, 30...Supply pipe (supply section), 31...Supply opening, 40...Discharge pipe (discharge section), 41...Discharge opening, 50...Pin fin, 60...Grid fin, 60a...First grid fin, 60b ...Second grid fin, 61...First pole, 62...Second pole, 63...Grid, 64...Grid point, 210...Cooling device, 220...Heat exchanger, 250...Pin fin, 250A...Pin fin, 251...First row of pins, 252...Second row of pins, 310...Cooling device, 320...Heat exchanger, 350...Pin fin, 410...Cooling device, 420...Heat exchanger, 450...Pin fin, 451...P Row, A1...Heat exchange area, A2...Pin fin area, A3...Representative area, Ac...Center, C1...Clearance, Dv...Vertical direction, D1...First direction, D2...Second direction, F...Refrigerant, H1...Height, H2...Height, H3...Height, H4...Height, L1...Width, P1...Pitch, P2...First pitch, P3...Second pitch, P4...Pitch, R1...Grid diameter, S1...Gap, T1...Thickness, W1...Width

Claims

1. A hollow casing having a bottom plate on which a heating element is placed, a top plate opposite the bottom plate, and side plates connecting the bottom plate and the top plate on the outer circumference, A heat exchanger is provided within the casing on the bottom plate, and has a frame-shaped partition between it and the side plate of the casing, which, when viewed from above, demarcates a frame-shaped outer peripheral passage, and which allows refrigerant from the outer peripheral passage to flow through its interior. A supply unit that supplies refrigerant from the outside to the aforementioned outer peripheral passage, A discharge section is connected to the region of the top plate that overlaps with the heat exchanger in a plan view, and discharges the refrigerant from inside the casing to the outside. A cooling device equipped with the following features.

2. The heat exchanger has a plurality of plate fins arranged in a first direction that intersects in the vertical direction, The cooling device according to claim 1, wherein each plate fin extends in the vertical direction and in a second direction intersecting the first direction.

3. The heat exchanger is provided in a position that overlaps with the discharge section in a plan view, and further has pin fins extending in the vertical direction. The cooling device according to claim 2, wherein the pin fins are sandwiched in the second direction by the plurality of plate fins and are formed in a shape that tapers towards the top.

4. The heat exchanger has a plurality of grid fins that extend so as to intersect in the vertical direction and are arranged in the vertical direction. The cooling device according to claim 1, wherein adjacent grid fins are arranged offset from each other in a direction that intersects the vertical direction.

5. A hollow casing having a bottom plate on which a heating element is placed, a top plate opposite the bottom plate, and side plates connecting the bottom plate and the top plate on the outer circumference, A heat exchanger is provided on the bottom plate within the casing, and a refrigerant is allowed to circulate inside it. The casing includes a supply unit that supplies refrigerant from the outside, A discharge section is connected to the region of the top plate that overlaps with the heat exchanger in a plan view, and discharges the refrigerant from inside the casing to the outside. Equipped with, The heat exchanger has a plurality of grid fins that extend so as to intersect in the vertical direction and are arranged in the vertical direction, The adjacent grid fins are arranged with a offset in a direction that intersects them vertically. The plurality of grid fins include a first grid fin and a second grid fin, The first lattice fin and the second lattice fin are arranged alternately in the vertical direction. In a vertical plan view, the grid points of the second grid fin are located at the center of the grid of the first grid fin. Cooling device.

6. The cooling device according to claim 4 or 5, wherein the heat exchanger further comprises vertically extending pin fins that support the plurality of grid fins.

7. The cooling device according to claim 6, wherein the pin fins are molded to a shape that tapers towards the top.

8. The cooling device according to claim 1, wherein the heat exchanger has a porous portion through which a refrigerant can pass.

9. The heat exchanger is provided in a position that overlaps with the discharge section in a plan view, and further has pin fins extending in the vertical direction. The cooling device according to claim 8, wherein the pin fins are sandwiched between the porous portion in a direction that intersects the vertical direction and are formed into a shape that tapers towards the top.

10. The cooling device according to claim 1, wherein the heat exchanger extends in the vertical direction and has a plurality of pin fins provided along the outer peripheral passage.

11. The cooling device according to claim 10, wherein the pitch between the pin fins increases as they move toward the discharge section in a direction that intersects the vertical direction.

12. The cooling device according to claim 10 or 11, wherein the pin fins are arranged in a direction that intersects the vertical direction and decreases in height towards the discharge section.

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