Cooling system for immersion cooling of electronic components

Abstract

The present invention relates to a cooling system (1) for immersion cooling of an electronic component (2), comprising a container (3) capable of being filled with a two-phase heat transfer fluid (4) in the liquid phase of which the electronic component (2) can be immersed, the container (3) having a gas chamber (5) above a surface (41) of the liquid heat transfer fluid (4) and a lid (6) for sealing the container (3) in a fluid-tight manner. The lid (6) or the container (3) has a side facing the gas chamber (5) and a side not facing the gas chamber (5) and a sealing device with a sealing surface that prevents the passage of gaseous fluids. Furthermore, at least the side facing the gas chamber (5) is configured as a vapor barrier that is resistant to chemical attack of the fluid.

Description

[Technical Field]

[0001] The present invention relates to a cooling system for immersion cooling of electronic components according to the preamble of claim 1. [Background technology]

[0002] Conventional electronic components are designed to operate within a specific temperature range depending on their application and have an upper temperature limit that must not be exceeded. Therefore, these components must be cooled as needed to maintain their internal temperatures below the specified upper limit. Cooling can be achieved by evaporating a dielectric heat-transfer fluid, such as a perfluorocarbon, fluorocarbon, fluoroketone, or fluorocarbon ether. Depending on their composition, the boiling point of the dielectric heat-transfer fluid at atmospheric pressure ranges from about 35°C to about 100°C. In this temperature range, the boiling point of the heat-transfer fluid at atmospheric pressure is lower than the upper temperature limit of conventional electronic components. The electronic component is immersed in the liquid phase of the heat-transfer fluid. When the boiling point of the heat-transfer fluid is reached at the surface of the electronic component in contact with the dielectric heat-transfer fluid, the fluid in the vicinity evaporates, absorbing excess heat from the electronic component.

[0003] Patent Document 1 describes a cooling device for electronic components immersed in a liquid. The fluid container has an open top and is sealed with a lid. For this purpose, the upper end of the container is designed as a flange, and a simple gasket is attached to its flat flange surface, which is then sealed with the lid. The container flange is firmly fastened to the lid with screws.

[0004] Furthermore, Patent Document 2 describes a two-phase immersion cooling system for electronic components. To minimize dielectric loss when using this two-phase system, the cooling tank is provided with extra free space above the condenser, ensuring that only a small percentage of the vapor from the heat exchange fluid reaches the top of the metal tank. Furthermore, the top of the metal tank is covered with a metal or glass lid or accessory plate. The gap between the container and the lid is sealed with an O-ring or other elastomeric gasket. While most of the gaseous dielectric condenses on the condenser, a certain amount of gas actually reaches the lid and penetrates into the gap between the lid and the container, even up to the gasket. The dielectric fluid has chemical properties that attack and damage sealing materials, so long-term sealing function cannot be guaranteed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] DE 3522798 A1 [Patent Document 2] US Patent Application Publication No. 2019 / 0357379 Summary of the Invention [Problem to be solved by the invention]

[0006] The invention is based on the task of further developing immersion cooling systems for electronic components. [Means for solving the problem]

[0007] The invention is described by the features of claim 1. The other related claims are advantageous embodiments and developments of the invention.

[0008] The present invention includes a cooling system for immersion cooling of an electronic component, comprising a container capable of being filled with a two-phase heat transfer fluid, the electronic component being immersed in the liquid phase thereof, the container having a gas chamber above the surface of the heat transfer fluid in the liquid phase, and a lid for fluid-tightly sealing the container.

[0009] The lid or container has a side facing the gas chamber and a side facing away from the gas chamber, and a sealing device with a sealing surface that prevents the passage of gaseous fluids, and further, at least the side facing the gas chamber is configured as a vapor barrier that is resistant to the chemical effects of fluids.

[0010] For the purposes of this invention, the term "vapor barrier" is used synonymously with the term "vapor barrier." The effect of a vapor barrier is a barrier that at least inhibits or completely prevents the passage of fluids.

[0011] In a two-phase system using immersion cooling, for example, an electronic component is placed at the bottom of a metal vessel. The metal vessel is filled with a dielectric heat-transfer fluid. The liquid phase of the dielectric is in direct thermal contact with the electronic component. During operation, the electronic component generates heat, which is dissipated from the component by evaporation of the heat-transfer fluid. The dielectric heat-transfer fluid is much less dense in its gas phase than its liquid phase, forming a gas chamber above the liquid surface. A condenser is placed within the gas chamber of the metal vessel as a heat exchanger, containing liquid water at a temperature at least 15°C below the boiling point of the dielectric. The gaseous dielectric fluid flows generally upward through the condenser. Upon contact with the condenser, the gaseous dielectric fluid releases heat to the condenser and returns to its liquid phase. Because the liquid dielectric is denser than the gaseous dielectric, gravity causes it to flow toward the bottom of the metal vessel. This cycle involves the liquid coming into contact with the electronic component evaporating, the vapor rising above the liquid, coming into contact with the condenser where it is converted back into liquid, and the liquid flowing back through the vapor, transferring heat generated by the electronic component to the condenser.

[0012] The present invention is based on the idea that a cooling system for immersion cooling of electronic components comprises a container and a lid for fluid-tightly sealing the container. The cooling system is filled with a two-phase heat transfer fluid, and the electronic components are immersed in the liquid phase. The gas phase released from the liquid heat transfer fluid collects in a gas chamber on the surface of the liquid heat transfer fluid in the container and penetrates into the remaining gap formed by the lid and the container. The lid or the container has a sealing device with a side facing the gas chamber and a side away from the gas chamber, and a sealing surface that prevents the passage of the gaseous fluid. Furthermore, at least the side facing the gas chamber is characterized as a vapor barrier that is resistant to the chemical effects of the fluid.

[0013] A particular advantage is that the sealing device facing the gas chamber is resistant to the chemical influence of the gas phase of the heat transfer fluid and does not corrode or damage the seals used therein, so that in practice any gas that may have entered the gap between the lid and the container is effectively shielded from the chemically sensitive seals, ensuring that the seal function is maintained permanently.

[0014] In a preferred embodiment of the present invention, the sealing surface of the gasket, which prevents the passage of gaseous fluids, can be elastically configured. The elastic material, such as a thermoplastic elastomer, can be a foam containing a large number of voids, such as a sealing tape, or a geometrically hollow structure, such as a hollow profile. Overall, an airtight seal is essentially provided on the sealing surface, which can withstand certain overpressures and underpressures inside the container.

[0015] Advantageously, the sealing device can be constructed as a single unit. On the side facing the gas chamber, the sealing device as a single component can act as a vapor barrier resistant to chemical attack of the fluid. On the other hand, the sealing surface facing away from the gas chamber can completely prevent the passage of gaseous fluids. Furthermore, the sealing device can be designed to go around the entire sealing surface without any interruptions.

[0016] In contrast, the sealing device can be designed in a multi-stage configuration, with a vapor barrier facing the gas chamber and a flexible sealing surface away from the gas chamber that prevents fluid passage. This type of sealing device design allows for the use of a wide range of materials with different properties, allowing for optimal material selection. A multi-stage sealing device can involve a gasket with a segmented peripheral sealing surface, a vapor barrier, and a sealing surface that is continuous with the gas chamber.

[0017] In an advantageous embodiment of the present invention, the sealing device on the side facing the gas chamber may be made of metal. Elastic metal seals are particularly preferred here, as their spring-like properties effectively seal the gap from gas exchange. Such elastic metal seals return to a defined position when the load is removed. This allows the elastic metal seal to generate a constant contact pressure on the sealing gap, or it may be designed as a film attached to a substrate.

[0018] In an advantageous embodiment of the invention, the sealing device on the side facing the gas chamber may consist of a film made of aluminum or an aluminum alloy, aluminum material being particularly suitable as a film material bonded to the substrate.

[0019] Advantageously, the material forming the sealing surface may consist of polysiloxane (silicone), fluoroelastomer, polytetrafluoroethylene (PTFE) or nitrile rubber (NBR). An important criterion in selecting a suitable sealing material is its chemical stability against the chemical influence of the heat transfer fluid. Other criteria include heat resistance and ageing resistance.

[0020] In a particularly preferred embodiment, the vapor barrier can be configured to be movable into the groove of the lid or the groove of the container by a spring mechanism. The spring action presses the vapor barrier against its respective counterpart, effectively sealing the gap against gas exchange. In particular, the sealing effect is enhanced when the vapor barrier penetrates into the groove.

[0021] In a further advantageous embodiment of the invention, the sealing device can be configured as a beam made of foam material, which typically increases the elasticity of the seal and provides a uniform sealing function over the entire contact surface of the lid and container.

[0022] Advantageously, the vapor barrier of the sealing device can be designed as a labyrinth seal, which enlarges the sealing surface and minimizes gas permeation of the heat transfer fluid.

[0023] An example of an embodiment of the present invention will be described in detail based on schematic diagrams. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a schematic diagram of a cooling system for an electronic component according to the present invention; [Figure 2] 1 is a schematic partial view of the lid and container in the region of the integrated sealing device. [Figure 3] 1 is a schematic partial view of a lid and a container in the region of a multi-stage sealing device. [Figure 4] 2 is a schematic partial view of a lid and a container in the region of another multi-stage sealing device. DETAILED DESCRIPTION OF THE INVENTION

[0025] In all the figures, corresponding parts are given the same reference numerals.

[0026] 1 shows a schematic diagram of a cooling system 1 for an electronic component 2 according to the invention. The cooling system 1 comprises a container 3 filled with a heat transfer fluid 4 in the liquid phase of which the electronic component 2 is immersed. The container 3 has a gas chamber 5 above the surface 41 of the liquid heat transfer fluid 4. The container 3 is sealed fluid-tight by a lid 6. At their common contact surface, the lid 6 or the container 3 has a sealing device 7, shown enlarged in the diagrammatic part A of FIG. 2, with a sealing surface that prevents the passage of the gaseous fluid.

[0027] The evaporated dielectric heat transfer fluid forms a gas chamber 5 with a gas phase above the surface 41, in which a heat exchanger 8 having a tube bundle 81 as a condenser is placed. Water at a temperature significantly lower than the boiling point of the dielectric flows through the tube bundle 81. When the gaseous fluid comes into contact with the tube bundle 81 condenser, it releases heat of condensation.

[0028] FIG. 2 shows a partial cross-sectional view A of the integrated sealing device 7 of the lid 6 and container 3 of FIG.

[0029] The sealing device 7 is beam-shaped and is embedded in the groove 61 of the lid 6. A sealing surface 74 that prevents the passage of fluids on gases is provided on the container side.

[0030] The one-piece sealing device 7 functions as a vapor barrier 70 on its side 71 facing the gas chamber 5, which is resistant to the chemical action of the fluid. The sealing surface 74 opposite the gas chamber 5 is protected by the vapor barrier 70, preventing the passage of the remaining gaseous fluid. A metal strip or foil is arranged on the side 71 facing the gas chamber 5 as the vapor barrier 70. Aluminum or aluminum alloys are particularly suitable as metals, and are preferably used as flexible film materials. In this way, the sealing device 7 can be integrated and seamlessly circumscribed over the entire sealing surface 74 between the container 3 and the lid 6. In special cases, the sealing device 7 can also be made of several parts joined together.

[0031] The resilient metal foil 70 as a vapor barrier effectively seals the gap through which the gas passes, so that only a small amount of gaseous fluid reaches the sealing surface 74 of the gasket 73 behind it. The metal foil is attached to a substrate, or in the case of an integrated type, directly to the gasket 73.

[0032] The gasket 73 of the sealing device 7 may be preferably made of a foam material in combination with an elastically flexible metal foil as the vapor barrier 70. The foam typically increases the resilience of the sealing material, resulting in a uniform sealing performance across the entire contact surface.

[0033] FIG. 3 shows a partial cross-sectional view A of the multi-stage sealing device 7 for the lid 6 and container 3 of FIG.

[0034] The sealing device 7 is multi-staged and includes a vapor barrier 70 with a side 71 facing the gas chamber and a flexible gasket 73 with a sealing surface 74 located behind the vapor barrier on a side 72 away from the gas chamber. Such a multi-stage sealing device 7 includes the vapor barrier 70 and the gasket 73 with the sealing surface 74, spaced apart from each other from the gas chamber 5. The vapor barrier 70 is embedded in a groove 61 in the lid 6. Similarly, the gasket 73 protrudes upward and is fixed in another groove. The sealing surface 74, which prevents the passage of a fluid on top of the gas, is provided on the container side.

[0035] In this embodiment, the vapor barrier 70 is movable into the groove 61 of the lid 6 by a spring mechanism 75. The spring action guides the vapor barrier 70 into the groove 61 and presses it against its respective counterpart, the container 3, thereby effectively sealing the gap against gas exchange towards the subsequent gasket 73.

[0036] In this case, the vapor barrier 70 of the sealing device 7 extends from the top surface of the vessel 3 to its side wall, creating a particularly large passage for the passage of gaseous fluids. Such a labyrinth seal increases the sealing surface and minimizes gas transmission of the heat transfer fluid through the gasket 73.

[0037] FIG. 4 shows a partial cross-section A of an alternative embodiment of the lid 6 and container 3 of FIG. 1 in the region of the multi-stage sealing device 7. In FIG.

[0038] The sealing device 7 comprises a vapor barrier 70 with a side 71 facing the gas chamber and a flexible gasket 73 with a side 72 away from the gas chamber and a sealing surface 74 arranged behind the vapor barrier. The multi-stage sealing device 7 comprises a vapor barrier 70 and a flexible gasket 73 with a sealing surface 74 arranged vertically and spaced apart from each other from the gas chamber 5. The vapor barrier 70 is embedded in a groove 61 in the lid 6. Similarly, the gasket 73 is fixed in another groove protruding upward. The gasket 73, which prevents the passage of gaseous fluids, has a sealing surface 74 and is arranged immediately behind the vapor barrier 70 on the container side. This further preferred embodiment combines the technical configurations shown and described in Figures 2 and 3 into a simple solution for the multi-stage sealing device 7. [Explanation of symbols]

[0039] 1. Cooling system 2. Electronic Components 3 containers 31 Container groove 4 Heat Transfer Fluid 41 Surface of a liquid heat transfer fluid 5 Gas Chamber 6 Lid 61 Lid groove 7 Sealing device 70 Vapor Barrier 71 Side of sealing device facing the gas chamber 72 Side of sealing device away from gas chamber 73 Gasket 74 sealing surface 75 Spring mechanism 8 Heat exchanger 81 tube bundle A Enlarged view of the sealing area

Claims

1. A cooling system (1) for immersion cooling of an electronic component (2), comprising: - a container (3) capable of being filled with a two-phase heat transfer fluid (4) capable of immersing an electronic component (2) in its liquid phase, said container (3) comprising a gas chamber (5) above the surface (41) of said liquid heat transfer fluid (4); - a lid (6) for sealing said container (3) in a fluid-tight manner, - said lid (6) or said container (3) has a sealing device (7) with a side (71) facing said gas chamber (5) and a side (72) facing away from said gas chamber (5), and a gasket (73) with a sealing surface (74) preventing the passage of gas fluids; A cooling system (1), characterized in that at least the side (71) facing the gas chamber (5) is configured as a vapor barrier (70) resistant to the chemical action of fluids.

2. 2. Cooling system (1) according to claim 1, characterized in that the sealing surface (74) of the gasket (73) that prevents the passage of gaseous fluid is formed elastically.

3. 3. Cooling system (1) according to claim 1 or 2, characterized in that the sealing device (7) is integrally formed.

4. 3. The cooling system (1) according to claim 1 or 2, characterized in that the sealing device (7) is multi-staged and comprises the vapor barrier (70) having a side (71) facing the gas chamber (5) and the flexible gasket (73) having the sealing surface (74) arranged behind the vapor barrier (70) on a side (72) not facing the gas chamber (5) and preventing the passage of gas.

5. 5. Cooling system (1) according to any one of claims 1 to 4, characterized in that the sealing device (7) on the side (71) facing the gas chamber (5) is made of metal.

6. 6. Cooling system (1) according to claim 5, characterized in that the sealing device (7) on the side (71) facing the gas chamber (5) is made from an aluminum or aluminum alloy film.

7. 7. The cooling system (1) according to any one of claims 1 to 6, characterized in that the material forming the sealing surface (74) of the gasket (73) consists of polysiloxane, fluoroelastomer, polytetrafluoroethylene and / or nitrile rubber.

8. 8. The cooling system (1) according to any one of claims 1 to 7, characterized in that the vapor barrier (70) is configured to be movable into the groove (61) of the lid (6) or the groove (31) of the container (3) by a spring mechanism (75).

9. 9. Cooling system (1) according to any one of claims 1 to 8, characterized in that the sealing device (7) is a beam made of foam material.

10. 10. The cooling system (1) according to any one of claims 1 to 9, characterized in that the vapor barrier (70) of the sealing device (7) is configured as a labyrinth seal.

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