Cooling system for the liquid immersion cooling of electronic components
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2026-01-14
- Publication Date
- 2026-08-13
Smart Images
Figure EP2026050737_13082026_PF_FP_ABST
Abstract
Description
[0001] Wieland-Werke AG 89070 Ulm, January 14, 2026 Bt / Be GP3464 - Foreign version
[0002] Description
[0003] Cooling system for liquid immersion cooling of electronic components
[0004] The invention relates to a cooling system for liquid immersion cooling of electronic components according to the preamble of claim 1.
[0005] Liquid immersion cooling systems, such as two-phase immersion cooling systems, are an efficient 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, preferably with a low boiling point, the heat generated by the electronic component evaporates the surrounding liquid heat transfer fluid, thus dissipating heat from the component. A condenser then liquefies the gaseous heat transfer fluid, which is returned to the reservoir for cooling.
[0006] From US patent 1,051,219, B2, a two-phase immersion cooling system with a cooling tank is known. A condensation chamber, in which the gaseous fluid produced during the cooling process is condensed, is connected to the liquid fluid in the cooling tank. A vapor diversion structure is arranged above the heat-generating electronic components, which are located within the cooling medium in the cooling tank. The evaporated fluid is directed by the vapor diversion structure into the condensation chamber for liquefaction. The condensation chamber is located within the cooling tank. Furthermore, from US patent 1,047,772, B1, a cooling system for computer components is known. A thermally conductive, dielectric heat transfer fluid in liquid and gaseous phases is contained in a pressure-controlled vessel. This fluid has a boiling point below 80°C at atmospheric pressure.Computer components are arranged within 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, which evaporates due to the heat generated by the computer components, into a dielectric liquid-phase fluid. The internal pressure of the pressure-controlled container is reduced to as low as 650 hPa. By controlling the pressure within the container at which the system operates, the user can influence the temperature at which the dielectric fluid evaporates, thereby increasing cooling capacity. Operating a computer system within a pressure-controlled container at an operating pressure that differs from ambient pressure usually requires a design modification of the entire system.
[0007] From publication EP 3453235 B1, a cooling system for immersion cooling of electronic components is known, comprising a pressure-tight tank configured to hold liquid heat transfer fluid into which the electronic components are immersed. A vapor space is also present above the surface of the liquid heat transfer fluid. A condenser is arranged outside the pressure-tight tank, the condenser having an inlet connected to the vapor space by a riser pipe and configured to receive heat transfer fluid vapor. The condenser also features a tightly sealable vapor outlet for residual gases and a condensate outlet with a condensate return line to the tank. The condensate return line is designed to allow condensed heat transfer fluid to flow back from the condensate outlet to the tank.The tank may also already contain additional condenser tubes for liquefying gaseous heat transfer fluid.
[0008] The cooling system also includes a filter in the condensate return line to remove moisture and / or metallic particles. The gaseous heat transfer fluid rises through a riser pipe into the condenser, where it condenses into a liquid heat transfer fluid. The condensate flows back through the return line and the filter into the tank. The filter is designed to remove any moisture remaining in the condensate and can also remove metallic particles that may have been picked up by the fluid from the condenser tubes.
[0009] The invention is based on the objective of further developing a cooling system for liquid immersion cooling of electronic components with respect to a heat exchanger device.
[0010] The invention is described by the features of claim 1. The further referenced claims relate to advantageous embodiments and further developments of the invention.
[0011] The invention includes a cooling system for liquid immersion cooling of electronic components, comprising
[0012] - a container with a container wall, which has inside a reservoir for liquid heat transfer fluid and in which positioning devices for electronic components are arranged, wherein the container has a gas space for gaseous heat transfer fluid,
[0013] - at least one heat exchanger device for the formation of liquid heat transfer fluid, which can be fed to the reservoir by gravity. According to the invention,
[0014] - which includes at least one heat exchanger in the gas space of the container,
[0015] - in the return flow path of the liquid heat transfer fluid from the at least one heat exchanger device to the reservoir for liquid heat transfer fluid, at least one filter device is arranged, and
[0016] - The filter device is arranged in the return flow of the liquid fluid below the heat exchanger device. The filter device is thus arranged in such a way that liquid heat transfer fluid dripping from the heat exchanger device is fed to the filter device by gravity.
[0017] "Arranged below" means, in particular, arranged sequentially directly within the fluid flow. The liquid heat transfer fluid that forms at the heat exchanger can drip directly onto a flat filter device under the influence of gravity. In this case, the filter device is located at least partially vertically below the heat exchanger device. Alternatively, the liquid heat transfer fluid can be collected before it reaches the filter device. The collection device used here is also located at least partially vertically below the heat exchanger device. In this part of the liquid fluid flow, the driving force from the heat exchanger device to the filter device is preferably the force of gravity.
[0018] In other words, "below" means located spatially below the heat exchanger, so that the liquid heat transfer fluid interacts with the filter material below as condensate and flows onward under the influence of gravity. This filtration process can remove even the smallest particles, measuring in the micrometer range.
[0019] The two-phase heat transfer fluid, also called refrigerant, is the outer medium in the container, in whose liquid portion the electronic components are immersed. The inner fluid in the heat exchanger is a single-phase heat transfer medium, for example, process water.
[0020] Inside the container, the electronic components are arranged in a cooling manner in a bath of liquid heat transfer fluid, which is cooled by evaporation of the liquid fluid. Non-condensable gases can be removed from the system before and / or during commissioning.
[0021] In the embodiment according to the invention, the computing components and the associated other components, such as power supplies, network connections and wiring connections, can be arranged in the container, which has an internal pressure that differs from the ambient pressure during operation.
[0022] In this context, it is also advantageous to bundle power, water, vacuum and network connections into a single bundle of cables to minimize the number of penetrations into the container and to reduce the risk of leaks, especially when the system is under vacuum or overpressure during operation.
[0023] In advantageous embodiments, the vessel is maintained during operation at a pressure up to 200 hPa below ambient atmospheric pressure, which helps to lower the boiling point of the two-phase heat transfer fluid and thus the operating temperature of the computer chips and other components. In some special embodiments, the pressure-controlled vessel can operate at an even lower pressure of up to 500 hPa below ambient pressure. At lower pressures, the inventive design features on the vessel wall for compensating for pressure differences are particularly advantageous.
[0024] Furthermore, the cooling system can advantageously include a control device designed to regulate, for example, the operation of the fluid circulation via the filter device and the pressure conditions in the container, depending on the temperature of the two-phase heat transfer fluid.
[0025] In a preferred embodiment of the invention, the heat exchanger device in the gas space can comprise a tube bundle of several heat exchanger tubes arranged relative to each other.
[0026] A tube bundle can contain several heat exchanger tubes arranged parallel to each other, each with two end tube sheets. A single tube sheet is particularly suitable when using U-shaped tubes, where both the inlet and outlet of the internal fluid are located on one tube sheet. Different arrangements of helical tubes can also be used in a tube bundle.
[0027] The tube sheet defines the position and spacing of the heat exchanger tubes within the tube bundle. The tube sheet and heat exchanger tubes form a self-contained module connected to the vessel wall. The tube sheet and vessel wall can have a fixed or detachable connection. In both cases, the tube sheet stabilizes the surrounding vessel wall against deformation. Particularly during operation, the tube sheet absorbs at least some of the deformation forces exerted on the surrounding vessel wall by negative or positive pressure. The tube sheet is typically designed to be more robust than the vessel wall and thus acts to stabilize the vessel against deformation. The modular design of the tube bundle itself inherently provides a stable structure against mechanical stresses. Detachable connections to the vessel wall also allow for particularly easy replacement of the modules.The simple exchange of modules with different cooling capacities and a variable number of heat exchanger tubes allows for corresponding flexibility in the design of the cooling system. In particular, a mechanically stabilizing structure for the tank is achieved.
[0028] In an advantageous embodiment of the invention, a connection box for distributing, diverting, or collecting the single-phase heat transfer medium flowing through the heat exchanger tubes can be arranged on the outside of at least one tube sheet of the container. If there are multiple tube sheets or points where the heat exchanger tubes penetrate the container wall, additional connection boxes for the single-phase heat transfer medium in the heat exchanger tubes are arranged. The supply and return lines for the internal fluid also branch off from these connection boxes, which are also referred to as water boxes.
[0029] The arrangement of the tube bundles or heat exchanger tubes within the vessel can be symmetrical or asymmetrical with respect to the vessel wall, or along inclined surfaces. Several independent tube bundles can also be distributed throughout the gas space of the vessel, together forming the heat exchanger assembly.
[0030] Advantageously, the heat exchanger tubes can have integral fins formed on the outside of the tube, helically arranged around the tube, and a channel can be formed between the fins.
[0031] These 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, and titanium, ensures that suitable material is available for various needs, particularly regarding durability and formability.
[0032] Alternatively, it is also advantageous for the heat exchanger device in the gas space to include a finned block, a fin bundle or a plate heat exchanger.
[0033] Fin-type heat exchangers can consist of copper or stainless steel tubes combined with aluminum or copper fins. Suitable fin patterns ensure good heat transfer and keep pressure loss low. Good thermal contact between the core tube and the fins can be achieved by mechanically expanding the core tubes.
[0034] The finned design of the heat exchanger allows for a large active external surface area for heat exchange. By using plates with different thermal properties, the heat exchangers can be adapted to a wide variety of applications.
[0035] In an advantageous embodiment of the invention, the liquid heat transfer fluid can flow over or through the filter device over a surface area.
[0036] In flow-through filters, the particle separation efficiency of the filter material is selected, taking into account the flow resistance, so that the liquid fluid generated during operation can pass through the filter without difficulty. Multi-layer filter materials can also be used, preferably in this case. The filter unit itself can be designed as a replaceable filter.
[0037] In an advantageous embodiment of the invention, the filter device can include a filtering effect for particles with a particle size of 1 micrometer and above.
[0038] In practice, the desired separation of particles down to 1 micrometer is sufficient and, in turn, ensures a sufficiently low flow resistance for the liquid heat transfer fluid flowing through the filter. With membrane filtration, pore sizes down to the sub-micrometer range are also conceivable for microfiltration.
[0039] Advantageously, the filter device can have a filter made of metallic fabric, fiberglass, ceramic material or textile material.
[0040] Open-pore sintered metal filters are preferably used as filters. Stainless steel mesh, for example, is suitable as a metallic fabric.
[0041] In a preferred embodiment of the invention, the container can be designed as a pressure vessel that can be operated with a negative pressure and / or positive pressure.
[0042] By controlling the pressure in the vessel at which the system operates, the cooling capacity can be increased. Mechanical stabilization through the arrangement of tube sheets on the vessel wall can significantly contribute to the overall pressure stability of the system. In a particularly preferred embodiment, fluid baffles can be arranged to optimize the flow behavior of the liquid heat transfer fluid and / or the distribution of gaseous heat transfer fluid.
[0043] Such additional guide vanes lead to optimized flow behavior for condensate return. Likewise, they can favorably influence the vapor distribution of the gaseous heat transfer medium in the cooling process, thereby optimizing the flow of the two-phase heat transfer fluid in the vapor phase to increase the rate and efficiency of condensation.
[0044] In a further advantageous embodiment of the invention, the filter device can be replaceable.
[0045] The arrangement of the filter in the container makes the filter material of the filter device easily accessible for replacement.
[0046] In a particularly preferred embodiment, the filter device can include a filter tray for collecting and filtering the liquid fluid.
[0047] The filter tray can be made of metal or plastic and can temporarily hold a larger quantity of the liquid fluid being filtered. The tray-shaped design serves, for example, as a buffer against fluctuating fluid flows.
[0048] Furthermore, the filter tray can, for example, be designed as a container with a bottom that is at least partially impermeable to the liquid fluid and a rim that is permeable to the fluid. The rim is preferably designed to be high enough to prevent any liquid fluid from overflowing, even with fluctuating fluid flows. In this way, the liquid fluid entering the filter tray is filtered of particles by the rim, which acts as a filter. The impermeable bottom creates a liquid bath in which the flow velocity is so low that particles begin to settle due to gravity. Larger particles settle at the bottom of the filter tray, thus protecting the filter material at the rim.
[0049] In a further advantageous embodiment of the invention, the filter device can be configured as a staged filter for the stepwise separation of different particle sizes.
[0050] These filter materials, which are preferably multi-layered, bind coarser particles in the upper layers and finer particles in the lower filter layers due to a porosity that decreases in the direction of flow.
[0051] Exemplary embodiments of the invention are explained in more detail with reference to the schematic drawings.
[0052] It shows:
[0053] Fig. 1 is a schematic front view of a cooling system according to the invention, Fig. 2 is a schematic side view of a cooling system according to the invention, and
[0054] Fig. 3 shows a schematic top view of a cooling system according to the invention, looking into the container.
[0055] Corresponding parts are marked with the same reference symbols in all figures.
[0056] 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, which can be filled internally with a two-phase heat transfer fluid. The two-phase heat transfer fluid constitutes the external fluid in the container 3, with a liquid heat transfer fluid component 4, in which the electronic components are immersed, and a gaseous heat transfer fluid component 5. A heat exchanger device 6 is arranged in the gas space 5 of the container 3 to form liquid heat transfer fluid 4.
[0057] In this advantageous embodiment, the heat exchanger assembly 6 in the gas space 5 consists of four tube bundles 7, each with several heat exchanger tubes 71 arranged parallel to each other.
[0058] In the illustrated embodiment shown in Fig. 1, the container is slightly tapered in the area of the liquid heat transfer fluid 4, as the container wall 3 projects inwards and only opens into the gas space 5. 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.
[0059] In the return path of the liquid heat transfer fluid 4, filter devices 2 are arranged below the heat exchanger devices 6 leading to the reservoir 34 for liquid heat transfer fluid. In Fig. 1, two superimposed tube bundles 7 are shown on the right side of the heat exchanger device 6, with a filter device 2 arranged below each tube bundle 7. This ensures that the heat transfer fluid, which has condensed on the heat exchanger tubes 71, is cleaned of particles immediately after dripping off.
[0060] In Fig. 1, two superimposed tube bundles 7 are shown on the left side of the heat exchanger assembly 6, with only one filter assembly 2 arranged below both tube bundles 7. Nevertheless, even in this embodiment, the entire liquid fluid formed in both tube bundles 7 is passed over the filter assembly 2 located below and cleaned of particles present in the fluid flow.
[0061] Fig. 2 shows a schematic side view of a cooling system 1. The electronic components 10 to be cooled are located in positioning devices 35 and 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 above.
[0062] In this advantageous embodiment, the heat exchanger assembly 6 in the gas space 5 consists of the tube bundles 7 shown in Fig. 2, each with several heat exchanger tubes 71 arranged parallel to one another and fixed in tube sheets 72. The two tube sheets 72 of a tube bundle 7 are rigidly connected to the remaining vessel wall 3 at opposite points via recesses 32 as passage points. The heat exchanger tubes 71 are arranged in a straight line between the two end tube sheets 72 in the vessel.
[0063] Connection boxes 8 are arranged on the outside of the container 3 on each of the tube sheets 72 for the distribution, deflection or collection of the internal fluid that can be passed through the heat exchanger tubes 71.
[0064] 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 internal fluid collected in the second connection box 8 is discharged via the outlet 82 to a cooling device (not shown).
[0065] The fluid guide plates 73 arranged on the tube bundle 7 stabilize the entire construction and lead to an optimized flow behavior for the return of the condensate via the filter device 2 to the liquid heat transfer fluid 4 of the reservoir 34.
[0066] The filter device 2 arranged below the tube bundles 7 is designed as a filter tray 21. The filter tray 21 has a raised circumferential rim, for example as a metal sieve, and is suitable for removing particles from the liquid heat transfer fluid 4 that has condensed on the tube bundles 7.
[0067] The filter tray 21 can temporarily hold a larger quantity of the liquid heat transfer fluid 4 to be filtered. The tray-shaped design also serves as a buffer for fluctuating fluid flows.
[0068] Figure 3 shows a schematic top view of a cooling system 1 looking into the tank 3. All inlet connection boxes 8 are centrally supplied with single-phase heat transfer medium via branch lines 81. After passing through the outlet connection boxes 8, the fluid is collected and centrally discharged via the outlet line 82. The filter unit 2 is arranged over a large area above the slope of the tank wall 31 shown in Figure 1 and with a certain overhang relative to the heat exchanger units 6 below them. (Reference numeral list)
[0069] Cooling system
[0070] Filter system
[0071] Filter tray
[0072] container
[0073] Container wall
[0074] Exclusion
[0075] Metal profile frame
[0076] reservoir
[0077] Positioning device
[0078] liquid heat transfer fluid, surface of the liquid fluid in the container, gaseous heat transfer fluid, gas space, heat exchanger device
[0079] Tube bundle
[0080] Heat exchanger tubes
[0081] Reedbed
[0082] Fluid guide plate
[0083] stiffening device
[0084] Junction box, water box
[0085] supply line
[0086] Derivation
[0087] electronic component
Claims
Patent claims 1. Cooling system (1 ) for liquid immersion cooling of electronic components (10), comprising - a container (3) with a container wall (31) which has inside a reservoir (34) for liquid heat transfer fluid (4) and in which positioning devices (35) for electronic components (10) are arranged, wherein the container (3) has a gas space (5) for gaseous heat transfer fluid, - at least one heat exchanger device (6) for the formation of liquid heat transfer fluid (4), which can be supplied to the reservoir (34) by gravity, characterized by - that at least one heat exchanger device (6) is arranged in the gas space (5) of the container (3), - that at least one filter device (2) is arranged in the return flow path of the liquid heat transfer fluid (4) from the at least one heat exchanger device (6) to the reservoir (34) for liquid heat transfer fluid (4), and - that the filter device (2) is arranged in the return flow of the liquid fluid (4) below the heat exchanger device (6).
2. Cooling system (1) according to claim 1, characterized in that the heat exchanger device (6) in the gas space (5) comprises a tube bundle (7) of several heat exchanger tubes (71) arranged relative to one another.
3. Cooling system (1) according to claim 2, characterized in that the heat exchanger tubes (71) have integral ribs formed on the outside of the tube, helically extending around the tube, and a channel is formed between the ribs.
4. Cooling system (1) according to claim 1, characterized in that the heat exchanger device (6) in the gas space (5) comprises a fin block, a fin bundle or a plate heat exchanger.
5. Cooling system (1) according to one of claims 1 to 4, characterized in that the liquid heat transfer fluid (4) flows over or through the filter device (2) over a surface area.
6. Cooling system (1) according to one of claims 1 to 5, characterized in that the filter device (2) comprises a filtering effect for particles with a particle size of 1 micrometer and above.
7. Cooling system (1) according to one of claims 1 to 6, characterized in that the filter device (2) has a filter made of metallic fabric, glass fiber, ceramic material or textile material.
8. Cooling system (1) according to one of claims 1 to 7, characterized in that the container (3) is designed as a pressure vessel which can be operated with a negative pressure and / or positive pressure.
9. Cooling system (1) according to one of claims 1 to 8, characterized in that fluid guide plates (73) are arranged for an optimized flow behavior of the liquid heat transfer fluid (4) and / or for the distribution of gaseous heat transfer fluid (5).
10. Cooling system (1) according to one of claims 1 to 9, characterized in that the filter device (2) is replaceable.
11. Cooling system (1 ) according to one of claims 1 to 10, characterized in that the filter device (2) comprises at least one filter tray (21) for collecting and filtering the liquid fluid.
12. Cooling system (1) according to one of claims 1 to 11, characterized in that the filter device (2) is configured as a stage filter for the staged separation of different particle sizes.