Cooling system for liquid immersion cooling of electronic components

Abstract

The invention relates to a cooling system (1) for liquid-immersed cooling of an electronic component (2), comprising: a container (3) having a container wall (31), said container being internally fillable with a two-phase heat transfer fluid (4) in which the electronic component (2) can be immersed, the container (3) having a gas space (5) above a surface (41) of the liquid heat transfer fluid (4), and-a heat exchanger device (6) located in the gas space (5) of the container (3) for the purpose of forming a liquid heat transfer fluid (4), said cooling system being characterized in that-the heat exchanger device (6) located in the gas space (5) consists of at least one tube bundle (7) of a plurality of heat exchanger tubes (71) arranged relative to one another, the tube bundle (7) is fixed in at least one tube sheet (72), and the at least one tube sheet (72) of the tube bundle (7) is formed as part of the container wall (31).

Description

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

[0002] Cooling systems for liquid immersion cooling, such as two-phase immersion cooling systems, are active cooling solutions for electronic components that generate a lot of heat during operation. When the components are immersed in a two-phase heat transfer fluid, which typically has a low boiling point, the heat generated by the electronic components can evaporate the surrounding liquid heat transfer fluid, whereby heat is dissipated from the electronic components. A condenser device liquefies the gaseous heat transfer fluid, which is then returned to the reservoir for cooling.

[0003] A two-phase immersion cooling system with a cooling tank is disclosed in the publication US 10 512 192 B2. A condensation chamber is connected to the liquid fluid in the cooling tank, in which the gaseous fluid generated during the cooling process is condensed. A vapor redirection structure is arranged above the heat-generating electronic components inside the cooling medium in the cooling tank. The evaporated fluid is introduced into the condensation chamber for liquefaction through the vapor redirection structure. The condensation chamber is completely inside the cooling tank. Only the supply and discharge lines of the fluid in the cooling pipe pass through the cooling tank wall.

[0004] In this context, a cooling system for computer components is disclosed in the publication US 10 477 726 B1. A heat-conducting dielectric heat transfer fluid having a liquid phase and a gas phase with a boiling point below 80°C at atmospheric pressure is located in a controlled pressure container. Computer components at least partially immersed in the liquid phase of the heat transfer fluid are arranged in the container. The dielectric electric phase fluid that has evaporated by the heat generated by the computer components is condensed by a condenser to form a dielectric liquid phase fluid. Inside the controlled pressure container, the internal pressure is reduced to 650 hPa. The user can influence the temperature at which the dielectric liquid evaporates by controlling the pressure in the container operated by the system. This enables an increased cooling capacity to be achieved. The operation of a computer system within a controlled pressure container at an operating pressure that deviates from the ambient pressure generally requires a structural adaptation of the system as a whole.

[0005] The object of the invention is to develop a cooling system for liquid immersion cooling of electronic components with respect to a heat exchanger arrangement.

[0006] The invention is characterized by the features of claim 1. Further dependent claims relate to advantageous embodiments and developments of the invention.

[0007] The invention comprises a cooling system for liquid immersion cooling of electronic components. The cooling system comprises a container with a container wall, the container being fillable with a two-phase heat transfer fluid, in the liquid phase of which the electronic components are immersible. The container has a gas space above the surface of the liquid heat transfer fluid. The cooling system also has a heat exchanger device located in the gas space of the container for the purpose of forming the liquid heat transfer fluid. The heat exchanger device in the gas space consists of at least one tube bundle of a plurality of heat exchanger tubes, which are arranged relative to each other and fixed in at least one tube sheet. At least one tube sheet of the tube bundle is formed as part of the container wall.

[0008] The two-phase heat transfer fluid, also called coolant, represents the external fluid located in the container, and the electronic components are immersed in its liquid component. The internal fluid located in the heat exchanger tubes is a single-phase heat transfer medium, such as process water.

[0009] The tube bundle can have a plurality of heat exchanger tubes arranged parallel to one another, with two tube sheets at the ends. Tube sheets are particularly suitable when using tubes extending in a U-shaped manner and where both the supply line and the discharge line of the internal fluid are located on the tube sheet. It is also possible to use different arrangements of spiral tubes in the tube bundle.

[0010] The arrangement of the tube bundles or heat exchanger tubes in the container can be carried out symmetrically and also asymmetrically, or along an inclination relative to the container wall.

[0011] The tube sheet fixes the position and spacing of the heat exchanger tubes in the tube bundle. The tube sheet and the heat exchanger tubes form a single module that is connected to the vessel wall.

[0012] The tube sheet and the container wall can comprise a fixed or even releasable connection. In both cases, the tube sheet stabilizes the surrounding container wall with respect to deformations. In particular, during operation, the tube sheet absorbs at least a portion of the deformation forces generated by the negative or positive pressure on the surrounding container wall. The tube sheet is designed to be more stable with respect to the container wall and thus acts as a stabilizer of the container with respect to deformations. The modular design of the tube bundle itself already has a stable structure with respect to mechanical influences. The releasable connection to the container wall also allows a particularly simple replacement of the modules. In particular, the simple replacement of modules with different cooling capacities together with a variable number of heat exchanger tubes allows a corresponding flexibility in the design of the cooling system. In particular, this achieves a mechanically stable structure of the container.

[0013] In the container, the electronic components are arranged in a manner suitable for cooling in a bath of a liquid heat transfer fluid, said electronic components being cooled by evaporation of the liquid fluid. The proportion of the non-condensable gas can be removed from the system before and / or during start-up. A plurality of separate tube bundles forming as a whole a heat exchanger device can also be arranged so as to be distributed in the gas space of the container.

[0014] In embodiments according to the invention, computing components and immersion cooling, as well as associated power supplies, network connections, wired connections, etc., may be arranged in a container having an internal pressure that deviates from ambient pressure during operation.

[0015] In this context, it is also advantageous to combine power, water, vacuum and network connections in one bundle of wires in order to minimize access holes into the container and to reduce the risk of leaks, particularly when the system is under vacuum or positive pressure during operation.

[0016] In an advantageous embodiment, during operation, the vessel is maintained at up to 200 hPa below the atmospheric ambient pressure, which helps to lower the boiling point of the two-phase heat transfer fluid and thereby lower the operating temperature of computer chips and other components. In several specific embodiments, the pressure-controlled vessel can have an even lower pressure, up to 500 hPa below ambient pressure. With increasingly lower pressures, the structural measures on the vessel wall according to the invention are particularly advantageous for compensating for pressure differences.

[0017] An embodiment of the cooling system according to the invention comprises a container designed to use a two-phase liquid immersion cooling system. The container contains a tank for a dielectric cooling fluid and a heat exchanger device for condensing the dielectric fluid from a gas phase to a liquid. It is also possible to arrange means for holding computer components and for distributing power from a power supply system to the devices and components located inside the container.

[0018] It goes without saying that a number of dedicated connections must be used in order to operate, for example, a computer system held in a container under negative pressure. Several embodiments of the system according to the invention may use a series of fiber optic interfaces that enable connection to the container and distribute these fibers to different holding devices for electronic components. Several embodiments of the container may contain sensors for safe operation. These sensors may include temperature sensors, level sensors, pressure sensors, position sensors, electrical sensors and / or cameras in order to ensure and automate the operation of the system.

[0019] These systems may include, for example, a pressure sensor inside the pressure controlled container that monitors the pressure to ensure that there is no substantial leak. A gas sensor may also be arranged on the outer surface of the pressure controlled container and detect the presence of dielectric vapor that may be present escaping from the pressure controlled container.

[0020] The cooling system may also advantageously have control means designed to control the operation of the fluid circulation, for example as a function of the temperature of the two-phase heat transfer fluid and the pressure conditions in the container.

[0021] An advantageous embodiment of the cooling system according to the invention may be an external frame which stabilizes the container and which may be designed from metal profiles in the form of a frame structure and which surrounds and supports the container. The frame structure may be an open design comprising a cover, side walls and doors for simple access during operation and for maintenance operations. This allows access to the cooling system at the on-site location.

[0022] In an advantageous embodiment, a mounting system can be set up by which the electronic component can be transported from the locking device to the operating position for its replacement. The mounting system can consist of a robot arm or a linear drive. By a suitable configuration of the device, the replacement of the component can be carried out via a fully automatic mounting system. Alternatively, gloves can also be arranged at a suitable container opening in order to replace the electronic component from the locking device to the operating position. This enables installation by manual access to the interior of the container.

[0023] In a preferred embodiment of the invention, the container wall may have at least one recess as a passage point for the heat exchanger tube, wherein the recess may be covered by at least one tube sheet in a fluid-tight manner. In practice, the passage point in the surface is configured to be slightly smaller than the tube sheet surface and is adapted in shape so that the tube sheet completely covers the recess and slightly overlaps the container wall. This helps the tube sheet and the adjacent container wall to be connected to each other as a joining part. As an alternative to the extended recess, multiple recesses may also exist separately with the surface through which each heat exchanger tube passes individually. The tube sheet is then arranged on the inner or outer surface of the container wall. However, the recess may also correspond exactly to the contour of the tube sheet, which in this case then fits precisely into the container wall.

[0024] Advantageously, the tube sheet can be a flat metal plate with guide holes for the heat exchanger tubes, wherein the thickness of the plate corresponds to at least three times the thickness of the remaining container wall. The material and thickness of the tube sheet are essentially determined by the supporting function and the stability of the structure. Thus, steel is suitable as a material, for example, whose plate thickness is designed to be large enough for increased stability.

[0025] In an advantageous embodiment of the invention, the tube sheet can be welded to the container wall. Compared to other joining methods, a welded connection represents a particularly stable material connection.

[0026] In an advantageous embodiment of the invention, connection boxes for distributing, transferring or collecting the single-phase heat transfer medium that can pass through the heat exchanger tubes can be arranged on at least one tube sheet on the outer surface of the container. In the case of a plurality of tube sheets or through-points at which the heat exchanger tubes pass through the container wall, in each case further connection boxes can be arranged for the single-phase heat transfer medium located in the heat exchanger tubes. Supply lines or discharge lines for the internal fluid branch off from these connection boxes (also indicated as water boxes).

[0027] Advantageously, the connection box can be removably connected to the tube sheet. Thus, in a simple manner, the heat exchanger tubes in the tube bundle can be accessed for maintenance purposes or for their replacement. The fixing point can also be positioned on a stable tube sheet by means of a threaded connection and a sealing surface, since its greater material thickness relative to the vessel wall requires a more stable connection.

[0028] The heat exchanger tubes can be designed as smooth tubes or even as finned tubes. In an advantageous embodiment, the heat exchanger tubes can have integral fins formed on the outer surface of the tubes and circulating in a spiral manner, and channels can be constructed between the fins.

[0029] The finned tubes are produced from a smooth tube which has been subjected to a forming process. The finned tubes are particularly suitable as components in efficient, compact and exceptionally stable heat exchangers with a high heat transfer coefficient. The tube surface is optimized for the specific heat transfer requirements of the application. The wide choice of materials including copper, copper alloys, steel or titanium ensures that the material suitable for the different needs is available for the respective requirements, especially with regard to durability and deformability.

[0030] Advantageously, the heat exchanger tubes can be connected in the guide holes of the tube sheet by widening, wherein a gas-tight and pressure-resistant connection is formed. In particular, the above-mentioned choice of material is usually a ductile metal or metal alloy, which allows widening of the heat exchanger tubes for connection to the tube sheet. This mechanically produced connection represents a resilient and stable joint.

[0031] Advantageously, the heat exchanger tubes can be soldered, adhesively bonded or welded into the tube sheet. Due to their material connection, this connection has proven to be gas-tight and mechanically stable enough to produce a compact modular tube bundle.

[0032] Advantageously, the tube bundle consisting of heat exchanger tubes can have two tube sheets which are connected at the ends at opposite points to the remaining container wall at recesses as through-points. Each tube sheet is then connected to the container wall at each through-point for a heat exchanger tube. The container wall is stabilized by each tube sheet so positioned.

[0033] In an advantageous embodiment of the invention, the heat exchanger tubes can be arranged in a straight line in the container between two tube sheets at the ends. In this way, the arrangement of the tube sheets and the heat exchanger tubes connected thereto is configured to be optimized in terms of the flow of the fluid flowing inside.

[0034] Such a tube bundle preferably extends in the longitudinal direction over its entire length near the inner wall of the container on both longitudinal sides of the container. Liquid heat transfer fluid near the container wall can thus flow back into the reservoir as condensate. The air flow formed over the electronic components during the cooling process is not affected or is only slightly affected in these side areas. For this purpose, the container can already have a shape that is correspondingly adapted to the fluid flow of the heat transfer fluid in terms of flow technology.

[0035] Advantageously, the container can be designed as a pressurized container that can be operated under negative and / or positive pressure. By controlling the pressure in the container operated according to the system, a greater cooling capacity can be achieved. By arranging the tube bundle on the container wall, the mechanical stabilization of the solution according to the invention can ensure an important contribution to the structural adaptation of the system as a whole.

[0036] In an advantageous embodiment of the invention, fluid baffles can be arranged for an optimized discharge behavior of the condensate, or for distributing the gaseous heat transfer fluid. Such additional baffles result in an optimal discharge behavior for the return condensate. Thus, the vapor distribution of the gaseous heat transfer fluid during the cooling process can be advantageously influenced, thereby optimizing the flow of the two-phase heat transfer fluid in the gas phase to increase the rate and efficiency of the condensation.

[0037] Advantageously, starting from the tube bundle, additional reinforcements can be arranged which are directed as far as the container wall and stabilize the container with respect to static and dynamic loads. To this end, the additional reinforcement of the cooling system is arranged substantially in the vicinity of sealing surfaces which, in the case of static and dynamic loads in the system, transfer the forces in an optimized manner and increase the stability and tightness of the entire system.

[0038] Advantageously, the reinforcement means can be arranged starting from the tube sheet, which already represents a suitable location for receiving and transmitting forces due to the stability of the entire tube bundle.

[0039] Exemplary embodiments of the invention are explained in more detail by means of the schematic drawings, in which:

[0040] Figure 1 shows a schematic front view of the cooling system,

[0041] Figure 2 A schematic diagram of the tube bundle is shown,

[0042] Figure 3 shows a schematic side view of the cooling system, and

[0043] Figure 4 A schematic plan view of the cooling system is shown, looking inside the vessel.

[0044] Components that correspond to each other are provided with the same reference numerals in all the figures.

[0045] Figure 1 A schematic front view of a cooling system 1 for liquid immersion cooling of electronic components is shown. The cooling system 1 comprises a container 3 with a container wall 31, which can be filled with a two-phase heat transfer fluid inside the container. The two-phase heat transfer fluid represents an external fluid located in the container 3, having a liquid heat transfer fluid portion 4 and a gaseous heat transfer fluid portion 5, in which the electronic components are immersed. In the container 3, a heat exchanger device 6 is arranged in the gas space 5 of the container 3 for forming the liquid heat transfer fluid 4.

[0046] In this advantageous embodiment, the heat exchanger device 6 in the gas space 5 comprises four tube bundles 7, in each case with a plurality of heat exchanger tubes 71 arranged parallel to one another. The heat exchanger tubes 71 are fixed in tube sheets 72. At least one tube sheet 72 of the tube bundle 7 is configured on the front surface as part of the container wall 3. Figure 1 In the two tube bundles 7 visible in the left part of the drawing, the region of the tube sheet 72 which overlaps with respect to the recess 32 is also shown (dashed outline). The tube sheet 72 thus completely covers the recess 32. The tube sheet 72 is connected as a joining component to the adjacent container wall 3, for example by a weld seam, in Figure 1 Not shown.

[0047] exist Figure 1 In the right-hand part of the drawing, the connection box 8 of the heat exchanger device 6 has been mounted on the tube sheet, so that the heat exchanger tubes 71 arranged at the rear thereof are only partially visible through the openings. During operation of the cooling system 1, the internal fluid as a single-phase heat transfer medium is introduced into the connection box 8 or discharged from the connection box 8 through these openings. Since water is used as the internal single-phase heat transfer medium in many cases, the connection box 8 is represented as a water tank.

[0048] In the embodiment shown Figure 1 In the embodiment, the container is slightly tapered in the area of ​​the liquid heat transfer fluid 4 by a container wall 3 which protrudes inwards and is open outwards only in the gas space. The shape of the container 3 is aided by a metal profile frame 33. Thus, the container 3 is already surrounded by a stable outer frame.

[0049] Figure 2 A schematic diagram of a tube bundle 7 of a cooling system is shown. In this embodiment, the tube bundle 7 is formed between two tube sheets 72 and comprises a plurality of heat exchanger tubes 71 tightly joined in the upper and lower regions. In each case, a metal plate with guide holes for the heat exchanger tubes 72 is arranged at the ends as a tube sheet 72. The material and thickness of the tube sheet 72 ensure the support function and stability of the structure.

[0050] Figure 3A schematic side view of a cooling system 1 is shown. An electronic component 2 to be cooled is immersed in a liquid heat transfer fluid 4 below the surface 41 of the liquid fluid. A heat exchanger arrangement 6 is located in the gas space 5.

[0051] In this advantageous embodiment, the heat exchanger device 6 in the gas space 5 consists of Figure 2 , which in each case have a plurality of heat exchanger tubes 71 which are arranged parallel to one another and are fixed in tube sheets 72. The two tube sheets 72 of the tube bundle 7 are fixedly connected to the remaining container wall 3 at opposite points at recesses as through points. The heat exchanger tubes 71 are arranged in a straight line in the container between the two tube sheets 72 at the ends.

[0052] In each case, a connection box 8 for distributing, transferring or collecting the internal fluid that can pass through the heat exchanger tubes 71 is arranged on the tube sheet 72 on the outer surface of the container 3 .

[0053] The first connection tank 8 is supplied with the internal fluid distributed therefrom into the heat exchanger tubes 71 via the supply line 81. The fluid collected in the second connection tank 8 is discharged to the cooling device ( Figure 3 not shown).

[0054] The fluid baffles 73 arranged on the tube bundle 7 stabilize the entire structure and result in an optimal drainage behavior for the return of condensate into the liquid heat transfer fluid 4 .

[0055] exist Figure 4 , a schematic plan view of the cooling system 1 is shown, observing the interior of the container 3. Via the supply line 81, all the input side connection boxes 8 are centrally supplied with single-phase heat transfer medium via branches, and after passing through the branches, they are collected in the output side connection box 8 and discharged centrally in the discharge line 82.

[0056] List of Reference Numerals

[0057] 1 Cooling system

[0058] 2 Electronic components

[0059] 3 Container

[0060] 31 container wall

[0061] 32 recess

[0062] 33 Metal profile frame

[0063] 4 Liquid heat transfer fluid

[0064] 41: Surface of liquid fluid in container

[0065] 5 Gas heat transfer fluid, gas space

[0066] 6 Heat exchanger device

[0067] 7 Discipline

[0068] 71 Heat exchanger tube

[0069] 72 tube sheet

[0070] 73 Fluid baffle

[0071] 74 Enhancement Device

[0072] 8 Connection box, water tank

[0073] 81 Discharge line

[0074] 82: Discharge pipeline

Claims

1. A cooling system (1) for liquid immersion cooling of electronic components (2), comprising: - a container (3) having a container wall (31), the container being able to be filled internally with a two-phase heat transfer fluid (4), in which the electronic component (2) can be immersed, wherein the container (3) has a gas space (5) above the surface (41) of the liquid heat transfer fluid (4), - a heat exchanger device (6) in the gas space (5) of the container (3) for the purpose of forming a liquid heat transfer fluid (4), It is characterized in that - the heat exchanger device (6) in the gas space (5) consists of at least one tube bundle (7) of a plurality of heat exchanger tubes (71) which are arranged relative to one another and are fixed in at least one tube sheet (72), - At least one tube sheet (72) of the tube bundle (7) is formed as part of the container wall (31).

2. The cooling system (1) according to claim 1, characterized in that The container wall (31) has at least one recess (32) as a passage point for a heat exchanger tube (71), wherein the recess (32) is covered in a fluid-tight manner by at least one tube sheet (72).

3. The cooling system (1) according to claim 1 or 2, characterized in that: The tube sheet (72) is a flat metal plate with guide holes for the heat exchanger tubes (71) and the thickness of the plate corresponds to at least three times the thickness of the remaining container wall (31).

4. Cooling system (1) according to one of claims 1 to 3, characterized in that The tube sheet (72) is welded to the container wall (31).

5. The cooling system (1) according to any one of claims 1 to 4, characterized in that A connection box (8) for distributing, transferring or collecting a single-phase heat transfer medium that can pass through the heat exchanger tubes (71) is arranged on at least one tube sheet (72) on the outer surface of the container (3).

6. The cooling system (1) according to claim 5, characterized in that The connection box (8) is removably connected to the tube sheet (72).

7. Cooling system (1) according to one of claims 1 to 6, characterized in that The heat exchanger tube (71) has integral fins formed on the outer surface of the tube and circulated in a spiral manner, and channels are constructed between the fins.

8. The cooling system (1) according to any one of claims 1 to 7, characterized in that The heat exchanger tubes (71) are connected by widening in the guide holes of the tube sheet (72), wherein a gas-tight and pressure-resistant connection is formed.

9. The cooling system (1) according to any one of claims 1 to 7, characterized in that The heat exchanger tubes (71) are soldered, adhesively bonded or welded into the tube sheet (72).

10. The cooling system (1) according to any one of claims 1 to 9, characterized in that The tube bundle (7) consisting of heat exchanger tubes (71) has two tube sheets (72) which are connected at ends at opposite points to the remaining container wall (31) at the recess (32) as a through point.

11. The cooling system (1) according to claim 10, characterized in that The heat exchanger tubes (71) are arranged in a straight line between two tube sheets (72) at the ends in the container (2).

12. The cooling system (1) according to any one of claims 1 to 11, characterized in that The container (2) is designed as a pressurized container capable of operating under negative pressure and / or positive pressure.

13. The cooling system (1) according to any one of claims 1 to 12, characterized in that The fluid baffles (73) are arranged for optimal drainage behavior of condensate or for distribution of the gaseous heat transfer fluid.

14. The cooling system (1) according to any one of claims 1 to 13, characterized in that Starting from the tube bundle (7), an additional reinforcement device (74) is arranged, which is led as far as the container wall (31) and stabilizes the container wall with respect to static and dynamic loads.

15. The cooling system (1) according to claim 14, characterized in that Starting from the tube sheet (72), a reinforcement device (74) is arranged.

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