Cooling system for the liquid immersion cooling of electronic components
Patent Information
- Application Number
- EP2023728591
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-06-20
- Filing Date
- 2023-05-17
- Publication Date
- 2025-04-23
AI Technical Summary
Existing cooling systems for electronic components using liquid immersion cooling face challenges in efficiently managing heat dissipation and structural stability, particularly when operating under pressure conditions that deviate from ambient pressure, which affects the boiling point of the heat transfer fluid and requires complex design adjustments.
A pressure-controlled container with a heat exchanger device comprising a tube bundle of heat exchanger tubes fixed in a tube sheet, which stabilizes the container wall and allows for flexible design by enabling independent module replacement, and includes a gas space above the liquid for efficient heat transfer and condensation, with additional features like fluid baffles and stiffening devices for enhanced stability and drainage.
The solution effectively lowers the operating temperature of electronic components by controlling pressure and enhancing cooling performance, while providing mechanical stability and ease of maintenance through modular design and efficient heat transfer, even under negative or positive pressure conditions.
Smart Images
Figure 1.1
Abstract
Description
[0001] Description
[0002] Cooling system for liquid immersion cooling of electronic components
[0003] The invention relates to a cooling system for liquid immersion cooling of electronic components according to the preamble of claim 1.
[0004] Liquid immersion cooling systems, such as two-phase immersion cooling systems, are an active cooling solution for electronic components that generate a lot of heat during operation. When the components are immersed in a two-phase heat transfer fluid, which usually has a low boiling point, the heat generated by the electronic component can evaporate the surrounding liquid heat transfer fluid, thereby removing heat from the electronic component. A condenser device liquefies the gaseous heat transfer fluid, which is then returned to the reservoir for cooling.
[0005] A two-phase immersion cooling system with a cooling basin is known from US Pat. No. 10,512,192 B2. A condensation chamber, in which the gaseous fluid produced during the cooling process is condensed, communicates with the liquid fluid in the cooling basin. A vapor diversion structure is arranged above the heat-generating electronic components located within the cooling medium in the cooling basin. The vaporized fluid is directed into the condensation chamber for condensation by means of the vapor diversion structure. The condensation chamber is located entirely within the cooling basin. Only the supply and discharge lines for the fluid contained in the cooling tubes pass through the cooling basin wall.
[0006] In this context, a cooling system for computer components is known from US 10477 726 B1. A pressure-controlled container contains a heat-conducting, dielectric heat transfer fluid in liquid and gaseous phases, which has a boiling point below 80°C at atmospheric pressure. Computer components are arranged in the container and are at least partially immersed in the liquid phase of the heat transfer fluid. A condenser condenses the dielectric gas-phase fluid evaporated by the heat generated by the computer components into a dielectric liquid-phase fluid. The internal pressure in the pressure-controlled container is reduced to as low as 650 hPa. By controlling the pressure in the container at which the system operates, the user can influence the temperature at which the dielectric fluid evaporates. This allows for increased cooling performance.The operation of a computer system within a pressure-controlled vessel at an operating pressure that deviates from the ambient pressure usually requires a structural adaptation of the system as a whole.
[0007] The invention is based on the object of developing a cooling system for liquid immersion cooling of electronic components with respect to a heat exchanger device.
[0008] The invention is defined by the features of claim 1. The further dependent claims relate to advantageous embodiments and developments of the invention.
[0009] The invention includes a cooling system for liquid immersion cooling of electronic components. The cooling system comprises a container with a container wall that can be filled with a two-phase heat transfer fluid, into whose liquid phase electronic components can be immersed. The container has a gas space above the surface of the liquid heat transfer fluid. Furthermore, the cooling system comprises a heat exchanger device in the gas space of the container for forming liquid heat transfer fluid. The heat exchanger device in the gas space consists of at least one tube bundle of several mutually arranged heat exchanger tubes, which are fixed in at least one tube sheet. The at least one tube sheet of a tube bundle is formed as part of the container wall.
[0010] The two-phase heat transfer fluid, also known as the refrigerant, represents the outer fluid in the vessel, in whose liquid portion the electronic components are immersed. The inner fluid, located in the heat exchanger tubes, is a single-phase heat transfer medium, such as process water.
[0011] A tube bundle can consist of several parallel heat exchanger tubes with two tube plates at their ends. A tube plate is particularly suitable for U-shaped tubes, where both the supply and discharge lines of the internal fluid are located at the tube plate. Different arrangements of coiled tubes can also be used in a tube bundle.
[0012] The arrangement of the tube bundles or heat exchanger tubes in the tank can be symmetrical or asymmetrical with respect to the tank wall or along slopes.
[0013] The tubesheet determines the position and spacing of the heat exchanger tubes in the tube bundle. The tubesheet and heat exchanger tubes form an independent module that is connected to the vessel wall. The tubesheet and vessel wall can be permanently or detachably connected. In both cases, the tubesheet stabilizes the surrounding vessel wall against deformation. Particularly during operation, the tubesheet absorbs at least a portion of the deformation forces exerted on the surrounding vessel wall by negative or positive pressure. The tubesheet is designed to be more stable than the vessel wall and thus stabilizes the vessel against deformation. The modular design of the tube bundle already provides a structure that is stable against mechanical influences. Detachable connections to the vessel wall also enable particularly easy replacement of the modules.The simple exchange of modules with different cooling capacities and a variable number of heat exchanger tubes enables corresponding flexibility in the design of the cooling system. In particular, a construction that mechanically stabilizes the vessel is achieved.
[0014] In the vessel, the electronic components are arranged in a suitable manner in a bath of liquid heat transfer fluid, which is cooled by evaporation of the liquid fluid. The portion of non-condensable gases can be removed from the system before and / or during commissioning. Several independent tube bundles can also be distributed throughout the gas space of the vessel, which together form the heat exchanger device.
[0015] In the embodiment according to the invention, the computing components and immersion cooling devices, as well as the associated power supplies, network connections, wiring connections, and the like, can be arranged in the vessel, which, during operation, has an internal pressure that differs from ambient pressure. In this context, it is also advantageous to combine power, water, vacuum, and network connections into a bundle of lines to minimize penetrations into the vessel and reduce the risk of leaks, especially when the system is under vacuum or overpressure during operation.
[0016] In advantageous embodiments, the vessel is maintained at up to 200 hPa below atmospheric ambient pressure during operation, which contributes to lowering the boiling point of the two-phase heat transfer fluid and thereby reducing the operating temperature of the computer chips and other components. In some specific embodiments, the pressure-controlled vessel can have an even lower pressure of up to 500 hPa below ambient pressure. At increasingly lower pressures, the inventive design measures on the vessel wall for compensating the pressure differences are particularly advantageous.
[0017] Embodiments of the cooling system according to the invention comprise a vessel configured to utilize a two-phase liquid immersion cooling system. The vessel contains a basin of dielectric cooling fluid and a heat exchanger for condensing the dielectric fluid from the gaseous phase to a liquid. Furthermore, devices for holding computer components and distributing power from the power system to the devices and components located within the vessel may be arranged.
[0018] It is understood that a variety of specialized connections must be used to operate a computer system within a container, for example, maintained at a vacuum. Some embodiments of the inventive system may utilize a series of fiber optic interfaces to enable connectivity within the container and to distribute the fibers to the various mounting devices for the electronic components. Some embodiments of the container may incorporate sensors for safe operation. These sensors may include temperature sensors, fluid level sensors, pressure sensors, position sensors, electrical sensors, and / or cameras to ensure and automate the operation of the system.
[0019] These systems may, for example, include pressure sensors inside the pressure-controlled vessel that monitor the pressure to ensure there are no significant leaks. Gas sensors located on the outside of the pressure-controlled vessel may also detect the presence of any dielectric vapor escaping from the pressure-controlled vessel.
[0020] In addition, the cooling system may advantageously comprise a control device designed to regulate 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] Advantageous embodiments of the cooling system according to the invention can include an external frame that stabilizes the container. This frame can be constructed from metal profiles in the form of a frame structure that encloses and supports the container. The frame structure can be an open design that includes a lid, side walls, and doors for easy access during operation and for maintenance work. This allows access to the cooling system at on-site locations.
[0022] In an advantageous embodiment, a placement system can be set up with which the electronic components can be transported from the lock device to the operating position for replacement. A placement system can consist of robotic arms or linear drive devices. With a suitable design of the device, the components can be replaced using a fully automated placement system. Alternatively, gloves can be placed at suitable container openings for replacing the electronic components from the lock device to the operating position. This enables placement through manual access to the interior of the container.
[0023] In a preferred embodiment of the invention, the container wall can have at least one recess as a passage point for the heat exchanger tubes, wherein the recess can be covered in a fluid-tight manner by the at least one tube sheet. In practice, the passage point is designed to be somewhat smaller in area than the tube sheet surface and is shaped so that the tube sheet completely covers the recess and slightly overlaps the container wall. This facilitates the connection of the tube sheet and the adjacent container wall to one another as joining parts. As an alternative to a flat recess, a plurality of recesses, each with a surface through which each of the heat exchanger tubes is individually passed, could also be provided. The tube sheet is then arranged on the inside or outside of the container wall.However, a recess can also correspond exactly to the outline of a tube sheet, which in this case fits exactly into the container wall.
[0024] Advantageously, the tube sheet can be a flat metal plate with passages for the heat exchanger tubes, with the plate thickness being at least three times the thickness of the remaining vessel wall. The material and thickness of the tube sheet significantly determine the support function and stability of the structure. For example, steel is a suitable material, with a plate thickness sufficiently thick to increase stability.
[0025] In an advantageous embodiment of the invention, the tube sheet can be welded to the vessel wall. Compared to other joining methods, a welded joint provides a particularly stable material bond.
[0026] In an advantageous embodiment of the invention, a junction box for distributing, redirecting, or collecting the single-phase heat transfer medium flowing through the heat exchanger tubes can be arranged on the at least one tube plate on the outside of the vessel. If there are multiple tube plates or points where the heat exchanger tubes pass through the vessel wall, additional junction boxes are arranged for the single-phase heat transfer medium contained in the heat exchanger tubes. The supply lines and discharge lines for the internal fluid also branch off from these junction boxes, which are also referred to as water boxes.
[0027] Advantageously, the terminal box can be detachably connected to the tube sheet. This allows easy access to the heat exchanger tubes in the tube bundle for maintenance or replacement. Using screw connections and sealing surfaces, the fixing points can also be located on the stable tube sheet, as its greater material thickness compared to the vessel wall ensures a more stable connection.
[0028] The heat exchanger tubes can be designed as smooth tubes or as finned tubes. In an advantageous embodiment, the heat exchanger tubes can have integral, helically circumferential fins formed on the outside of the tube, with a channel formed between the fins. Such finned tubes are manufactured from smooth tubes that have undergone a forming process. They are particularly suitable as components in highly efficient, compact, and extremely stable heat exchangers with a high heat transfer coefficient. The tube surfaces are optimized for the specific heat transfer requirements of the application. A wide selection of materials, including copper, copper alloys, steels, or titanium, ensures that suitable materials are available for different needs, particularly with regard to durability and formability.
[0029] Advantageously, the heat exchanger tubes can be connected to the tubesheet penetrations by expanding, creating a gas-tight and pressure-resistant connection. In particular, the aforementioned selection of materials is mostly made of ductile metals or metal alloys, which allow the heat exchanger tubes to be expanded to connect to the tubesheet. Such mechanically created connections represent a resilient and stable joint.
[0030] Advantageously, the heat exchanger tubes can be soldered, glued, or welded into the tubesheet. Such connections prove to be both gas-tight and mechanically stable due to their material bond, creating a compact, modular tube bundle.
[0031] Advantageously, a tube bundle of heat exchanger tubes can have two tube plates, which are connected to the remaining vessel wall at opposite ends via recesses that serve as passage points. Each tube plate is then connected to the vessel wall at each passage point for the heat exchanger tubes. Each tube plate positioned in this way stabilizes the vessel wall. In an advantageous embodiment of the invention, the heat exchanger tubes can be arranged in a straight line between the two end tube plates in the vessel. In this way, the tube plate and the associated arrangement of the heat exchanger tubes are designed to be flow-optimized for the fluid flowing inside.
[0032] Such tube bundles preferably run longitudinally along two long sides of the vessel near the inner vessel wall, along the entire length. This allows the liquid heat transfer fluid to flow back into the reservoir as condensate near the vessel wall. In these side areas, the gas flow around the electronic components that develops during the cooling process is not affected or only slightly affected. For this purpose, the vessel itself can have a shape that is aerodynamically adapted to the flow of the heat transfer fluid.
[0033] Advantageously, the vessel can be designed as a pressure vessel that can be operated at negative and / or positive pressure. By controlling the pressure in the vessel at which the system operates, increased cooling capacity can be achieved. The mechanical stabilization of the inventive solution through the arrangement of tube sheets on the vessel wall can make an important contribution to the structural adaptation of the system as a whole.
[0034] In an advantageous embodiment of the invention, fluid baffles can be arranged to optimize the drainage behavior of the condensate or to distribute the gaseous heat transfer fluid. Such additional baffles lead to optimized drainage behavior for the return of the condensate. Likewise, the vapor distribution of the gaseous heat transfer fluid in the cooling process can be advantageously influenced, thus optimizing the flow of the two-phase heat transfer fluid in the vapor phase to increase the rate and efficiency of condensation.
[0035] Advantageously, additional stiffening devices can be arranged starting from the tube bundle, extending to the vessel wall and stabilizing it against static and dynamic loads. For this purpose, the additional stiffening of the cooling system is arranged primarily near the sealing surfaces, which optimally dissipate the force in the system under static and dynamic loads and increase the stability and tightness of the overall system.
[0036] Advantageously, the stiffening devices can be arranged starting from the tube sheet. The tube sheet itself represents a suitable location for absorbing and transmitting forces due to the stability of the entire tube bundle.
[0037] Embodiments of the invention are explained in more detail with reference to the schematic drawings.
[0038] Showing:
[0039] Fig. 1 is a schematic front view of a cooling system,
[0040] Fig. 2 is a schematic view of a tube bundle,
[0041] Fig. 3 is a schematic side view of a cooling system, and
[0042] Fig. 4 is a schematic plan view of a cooling system looking into the tank.
[0043] Corresponding parts are provided with the same reference numerals in all figures.
[0044] Fig. 1 shows a schematic front view of a cooling system 1 for liquid immersion cooling of electronic components. The cooling system 1 comprises a container 3 with a container wall 31, the interior of which can be filled with a two-phase heat transfer fluid. The two-phase heat transfer fluid represents the external fluid located in the container 3, comprising a liquid heat transfer fluid portion 4, in which the electronic components are immersed, and a gaseous heat transfer fluid portion 5. A heat exchanger device 6 is arranged in the gas space 5 of the container 3 to form liquid heat transfer fluid 4.
[0045] In this advantageous embodiment, the heat exchanger device 6 in the gas space 5 consists of four tube bundles 7, each 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 a tube bundle 7 is designed here as the end part of the container wall 3. In the two tube bundles 7 visible in the left-hand part of Figure 1, the overlap area of the tube sheet 72 (dashed outline) opposite the recess 32 is also illustrated. The tube sheet 72 thus completely covers the recess 32. There, the tube sheet 72 is connected to the adjacent container wall 3 as a joining part, for example by a weld seam not shown in Figure 1.
[0046] In the right-hand part of Figure 1, the terminal boxes 8 of the heat exchanger device 6 are already mounted on the tube sheets, leaving the heat exchanger tubes 71 arranged behind them only partially visible through openings. During operation of the cooling system 1, the internal fluid is introduced into or discharged from the terminal box 8 as a single-phase heat transfer medium through these openings. Since water often serves as the internal single-phase heat transfer medium, the terminal box 8 is referred to as a water box.
[0047] In the illustrated embodiment, the container in Fig. 1 is slightly tapered in the area of the liquid heat transfer fluid 4, with the container wall 3 projecting inward and only opening in the gas space. The shape of the container 3 is supported by a metal profile frame 33. The container 3 is therefore already enclosed by a stabilizing outer frame.
[0048] Fig. 2 shows a schematic view of a tube bundle 7 of a cooling system. In this embodiment, a tube bundle 7 is formed between two tube sheets 72 from several heat exchanger tubes 71, which are tightly packed in the upper and lower regions. A metallic plate with passages for the heat exchanger tubes 72 is arranged at the end of each tube sheet 72. The material and thickness of the tube sheet 72 provide support and stability for the structure.
[0049] Fig. 3 shows a schematic side view of a cooling system 1 .
[0050] The electronic components 2 to be cooled are immersed in the liquid heat transfer fluid 4 below the surface 41 of the liquid fluid. The heat exchanger device 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 the tube bundles 7 shown in Figure 2, each comprising a plurality of parallel heat exchanger tubes 71, which are fixed in tube plates 72. The two tube plates 72 of a tube bundle 7 are firmly connected to the remaining vessel wall 3 at opposite points at recesses serving as passage points.
[0052] The heat exchanger tubes 71 are arranged in a straight line between the two terminal tube sheets 72 in the vessel.
[0053] On the tube sheets 72, connection boxes 8 are arranged on the outside of the container 3 for distributing, redirecting, or collecting the internal fluid flowing through the heat exchanger tubes 71. A first connection box 8 is supplied with internal fluid via a supply line 81, which is then distributed into the heat exchanger tubes 71. The fluid collected in the second connection box 8 is discharged via the discharge line 82 to a cooling device not shown in Figure 3.
[0054] The fluid guide plates 73 arranged on the tube bundle 7 stabilize the entire construction and lead to an optimized drainage behavior for the return of the condensate into the liquid heat transfer fluid 4. Fig. 4 shows a schematic plan view of a cooling system 1 with a view into the tank 3. Via the supply lines 81, all inlet-side connection boxes 8 are centrally supplied with single-phase heat transfer medium through branches and, after passing through the outlet-side connection boxes 8, are collected and centrally discharged in the discharge line 82.
[0055] List of reference symbols
[0056] 1 cooling system
[0057] 2 electronic component
[0058] 3 containers
[0059] 31 Container wall
[0060] 32 recess
[0061] 33 metal profile frames
[0062] 4 liquid heat transfer fluid
[0063] 41 Surface of the liquid fluid in the container
[0064] 5 gaseous heat transfer fluid, gas space
[0065] 6 Heat exchanger device
[0066] 7 tube bundles
[0067] 71 heat exchanger tubes
[0068] 72 tube sheet
[0069] 73 Fluid baffle
[0070] 74 stiffening device
[0071] 8 Connection box, water box
[0072] 81 supply line
[0073] 82 Derivation
Claims
Patent claims Cooling system (1) for liquid immersion cooling of electronic components (2), comprising - a container (3) with a container wall (31) which can be filled inside with two-phase heat transfer fluid (4) into which electronic components (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 formation of liquid heat transfer fluid (4), characterized in that, - that the heat exchanger device (6) in the gas space (5) consists of at least one tube bundle (7) of several heat exchanger tubes (71) arranged relative to each other, which are fixed in at least one tube sheet (72), - that at least one tube sheet (72) of a tube bundle (7) is formed as part of the container wall (31). Cooling system (1) according to claim 1, characterized in that the container wall (31) has at least one recess (32) as a passage for the heat exchanger tubes (71), wherein the recess (32) is fluid-tightly covered by the at least one tube sheet (72). Cooling system (1) according to claim 1 or 2, characterized in that the tube sheet (72) is a flat metallic plate with passages for the heat exchanger tubes (71) and the thickness of the plate is 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. Cooling system (1) according to one of claims 1 to 4, characterized in that a connection box (8) for distributing, diverting or collecting the single-phase heat transfer medium that can be passed through the heat exchanger tubes (71) is arranged on the at least one tube sheet (72) on the outside of the container (3).
6. Cooling system (1) according to claim 5, characterized in that the connection box (8) is detachably connected to the tube sheet (72).
7. Cooling system (1) according to one of claims 1 to 6, characterized in that the heat exchanger tubes (71) have integral ribs formed on the outside of the tube, helically circumferential and a channel is formed between the ribs.
8. Cooling system (1) according to one of claims 1 to 7, characterized in that the heat exchanger tubes (71 ) are connected in the passages of the tube sheet (72) by expansion, wherein a gas-tight and pressure-resistant connection is formed.
9. Cooling system (1) according to one of claims 1 to 7, characterized in that the heat exchanger tubes (71) are soldered, glued or welded into the tube sheet (72).
10. Cooling system (1) according to one of claims 1 to 9, characterized in that a tube bundle (7) is made of heat exchanger tubes (71) have two tube sheets (72) which are connected at opposite ends to the rest of the container wall (31) at recesses (32) as passage points.
11. Cooling system (1) according to claim 10, characterized in that the heat exchanger tubes (71) are arranged in a straight line between the two terminal tube sheets (72) in the container (2).
12. Cooling system (1) according to one of claims 1 to 11 , characterized in that the container (2) is designed as a pressure vessel which can be operated with a negative pressure and / or positive pressure.
13. Cooling system (1) according to one of claims 1 to 12, characterized in that fluid guide plates (73) are arranged for optimized drainage behavior of the condensate or for the distribution of gaseous heat transfer fluid.
14. Cooling system (1 ) according to one of claims 1 to 13, characterized in that additional stiffening devices (74) are arranged starting from the tube bundle (7), which extend to the container wall (31 ) and stabilize it against static and dynamic loads.
15. Cooling system (1) according to claim 14, characterized in that the stiffening devices (74) are arranged starting from the tube sheet (72).