Cooling system for liquid immersion cooling of electronic components

Abstract

The present invention relates to a cooling system (1) for liquid immersion cooling of an electronic component (2), comprising a container (3) which can be filled inside with a two-phase heat transfer fluid (4) for immersing the electronic component (2) in a liquid phase. The container (3) has a gas chamber (5) above the surface (41) of the liquid heat transfer fluid (4). To form the liquid heat transfer fluid (4), a heat exchanger (6) is provided in the gas chamber (5) of the container (3). The cooling system (1) comprises a first condensing device unit (7) arranged outside the container (3). The first condensing device unit (7) is connected to the gas chamber (5) of the container (3) by a first supply line (71) for exchanging a gaseous medium, and has a first return line (72) for the condensed heat transfer fluid to the container (3). A second condensing device unit (8) is arranged. The second condensing device unit (8) is connected to the first condensing device unit (7) via a second supply line (81) for exchanging a gaseous medium, and has a second return line (82) for the condensed heat transfer fluid to the container (3). The second condensing device unit (8) is characterized by having an outlet (83) through which a residual gas phase can be discharged.

Description

Technical Field

[0004] ,

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

Background Art

[0002] A cooling system for liquid immersion cooling is, for example, a two-phase immersion cooling system, which is an active cooling solution for electronic components that generate a lot of heat during operation. When the components are immersed mainly in a two-phase heat transfer fluid having a low boiling point, the heat generated from the electronic components vaporizes the surrounding liquid heat transfer fluid, thereby dissipating the heat from the electronic components. The gaseous heat transfer fluid is liquefied by a condenser and then returned to the reservoir for cooling.

[0003] From Patent Document 1, a two-phase immersion cooling system having a cooling tank is known. A condensation chamber that condenses the gaseous fluid generated during the cooling process is connected to the liquid fluid in the cooling tank. Here, the heat-generating electronic components are in the cooling medium in the cooling tank, and a vapor bypass structure is arranged above it. The vaporized fluid is sent to the condensation chamber for liquefaction using the vapor bypass structure. The condensation chamber is completely inside the cooling tank.

[0004] In this regard, a cooling system for computer components is known from Patent Document 2. A heat-conducting dielectric heat transfer fluid, having a boiling point below 80°C at atmospheric pressure, exists in both liquid and gaseous phases within a pressure-controlled container. Computer components are placed within the container, at least partially immersed in the liquid phase of the heat transfer fluid. A condenser condenses the dielectric gaseous fluid, vaporized by the heat generated from the computer components, into a dielectric liquid phase. Inside the pressure-controlled container, the internal pressure is reduced to 650 hPa. By controlling the pressure within the container in which the system operates, the user can influence the vaporization temperature of the dielectric liquid. This makes it possible to improve cooling performance. Operating a computer system in a pressure-controlled container at an operating pressure different from the ambient pressure almost always requires adapting the overall structural design of the system.

[0005] From Patent Document 3, a cooling system is known comprising a container capable of being filled with a two-phase heat transfer fluid as a coolant, in which electronic components can be immersed in the liquid phase. The container has a gas chamber above the surface of the liquid heat transfer fluid. Above the container is a separate external condenser, which is configured to condense the vapor phase of the heat transfer fluid and return it to the container containing the electronic components as a liquid coolant. To this end, the system comprises a return line and a supply line, which are connected to both the condenser and the container, thereby forming a heat exchange loop. Furthermore, the system also comprises a collection container located on the supply line and designed to collect the condensed liquid heat transfer fluid before the coolant is sent to the container. This storage device also provides a pre-cooling capacity for the cooling system.

[0006] Patent Document 4 provides a known cooling system for immersion cooling of electronic components, comprising a pressure-resistant tank configured to hold a liquid heat transfer fluid, in which the electronic equipment is immersed. Furthermore, a steam chamber is located above the surface of the liquid heat transfer fluid. Outside the pressure-resistant tank, a condenser is positioned, which is connected to the steam chamber via a vertical tube and has an inlet configured to contain the heat transfer fluid. Furthermore, the condenser has a sealable steam outlet for residual gas and a condensate outlet with a condensate return line to the tank. The condensate return line is configured to allow the condensed heat transfer fluid to return from the condensate outlet to the tank. Further condenser tubes for liquefying the gaseous heat transfer fluid may already be installed inside the tank. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] U.S. Patent No. 10512192 [Patent Document 2] U.S. Patent No. 10477726 [Patent Document 3] U.S. Patent Application Publication No. 2021 / 0153392 [Patent Document 4] European Patent No. 3453235 [Overview of the project] [Problems that the invention aims to solve]

[0008] The present invention relates to a heat exchanger for heat transfer fluids and is based on the challenge of further developing a cooling system for immersion cooling of electronic components. [Means for solving the problem]

[0009] The present invention relates to a cooling system for immersion cooling of electronic components, comprising a container, the interior of which can be filled with a two-phase heat transfer fluid capable of immersing electronic components in a liquid phase, the container having a gas chamber above the surface of the liquid heat transfer fluid, a heat exchanger provided in the gas chamber of the container to form the liquid heat transfer fluid, and a first condenser unit disposed outside the container, the first condenser unit being connected to the gas chamber of the container by a first supply line for substance exchange of a gaseous medium, and a first return line for the condensed heat transfer fluid to the container, wherein a second condenser unit is disposed, the second condenser unit being connected to the first condenser unit by a second supply line for substance exchange of a gaseous medium, and a second return line for the condensed heat transfer fluid to the container, and the second condenser unit having an outlet for discharge of residual gas phase. [Brief explanation of the drawing]

[0010] [Figure 1] It is a schematic diagram of a cooling system 1 for liquid immersion cooling of an electronic component 2.

Embodiments for Carrying Out the Invention

[0011] The present invention includes a cooling system for immersion cooling of electronic components. The cooling system comprises a container in which a two-phase heat transfer fluid can be filled, and electronic components can be immersed in the liquid phase. The container has a gas chamber above the surface of the liquid heat transfer fluid. Furthermore, the cooling system comprises a heat exchanger in the gas chamber of the container to form the liquid heat transfer fluid. Furthermore, the cooling system comprises a first condenser unit located outside the container, which is connected to the gas chamber of the container by a first supply line to exchange a gaseous medium and has a first return line for the condensed heat transfer fluid to the container. According to the present invention, a second condenser unit is provided, which is connected to the first condenser unit by a second supply line to exchange a gaseous medium and has a second return line for the condensed heat transfer fluid to the container. The second condenser unit has an outlet from which residual gas phase can be discharged.

[0012] The vessel can be implemented in a form that offers excellent pressure resistance. Advantageously, the vessel may be implemented as a pressure vessel capable of operating under negative and / or positive pressure. By controlling the pressure within the vessel in which the cooling system is operating, improved cooling performance can be achieved.

[0013] Preferably, the heat exchanger in the gas chamber consists of at least one tube bundle of a number of heat exchange tubes arranged relative to each other. The tube bundle may have a number of heat exchange tubes arranged parallel to each other, each having two end tube sheets. The tube bundle or heat exchange tubes in the container may be arranged symmetrically and asymmetrically with respect to the container wall, or along an incline.

[0014] Preferably, the heat exchanger tubes are finned tubes manufactured from smooth tubes that have undergone a forming process. Finned tubes are particularly suitable as components in heat exchangers that are highly efficient, compact, extremely stable, and have a high heat transfer coefficient. The tube surface is optimized for the specific heat transfer requirements of the application. A wide range of material options, including copper, copper alloys, steel, titanium, or titanium alloys, allows for the use of materials suitable for various requirements, particularly in terms of durability and deformability.

[0015] Two-phase heat transfer fluids, also known as refrigerants, are the external fluid within a container, with electronic components immersed in the liquid portion. The internal fluid present in heat exchange tubes is typically a single-phase heat transfer medium, such as process water, glycol, or thermal oil. However, two-phase fluids can also be used in combination with cooling circuits.

[0016] Within the container, electrical components are placed in a bath of liquid heat transfer fluid in a manner suitable for cooling, and the electrical components are cooled by the vaporization of the liquid fluid. In this case, the non-condensable gaseous portion can be efficiently removed from the system before and / or during operation.

[0017] In embodiments of the present invention, computer components and immersion cooling devices, as well as related power supplies, network connections, wiring connections, etc., can be placed inside the container, and during operation, the container has an internal pressure different from the ambient pressure.

[0018] In this regard, it is also advantageous to bundle electrical, water, negative pressure, and network connections into a single wire to minimize feedthrough into the container and reduce the risk of leakage, especially when the system is under negative or positive pressure while operating.

[0019] In advantageous embodiments, the vessel is maintained at a pressure up to 200 hPa below ambient atmospheric pressure during operation, which contributes to lowering the boiling point of the two-phase heat transfer fluid, thereby reducing the operating temperature of the computer chip and other components. In some special embodiments, the pressure-controlled vessel can have a pressure up to 500 hPa below ambient pressure.

[0020] Embodiments of a cooling system according to the present invention include a vessel designed to use a two-phase liquid immersion cooling system. This vessel contains a tank comprising a dielectric cooling fluid, a heat exchanger, and an external condenser unit connected in series to condense the dielectric fluid from a gas phase to a liquid phase. A first condenser unit, located outside the vessel, is intended to condense a gaseous heat transfer fluid, which also contains a certain proportion of air and water vapor, into as much liquid heat transfer fluid as possible. The residual gas phase of this first condenser unit reaches a second condenser unit via a second supply line. Here, the remaining heat transfer fluid is almost completely condensed from the gas phase, leaving mainly air and water vapor as the residual gas phase. In this case, the purpose of separating the liquid heat transfer fluid is to retain the water vapor in the gas phase due to the appropriate cooling performance of the system. This residual gas mixture is discharged from the cooling system via the outlet of the second condenser unit.

[0021] Furthermore, devices for holding computer components and devices for distributing electricity from a power supply system to devices and components within the container can also be provided. Needless to say, numerous special connections are used to operate a computer system inside a container maintained under negative pressure, for example. In some embodiments of the system according to the present invention, connectivity within the container can be enabled by using a series of fiber optic interfaces, and fibers can be distributed to various holding devices for electronic components. In some embodiments of the container, sensors can be included 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.

[0022] These systems can, for example, include pressure sensors inside a pressure-controlled vessel to monitor the pressure and ensure that there are no significant leaks. Similarly, gas sensors can be placed outside the pressure-controlled vessel to detect the presence of dielectric vapors that may leak from the vessel.

[0023] In addition, advantageously, the cooling system may also have a control device, which is configured to control, for example, the operation of fluid circulation, which is a function of the temperature of the two-phase heat transfer fluid, and to control the pressure ratio within the container.

[0024] An advantageous embodiment of the cooling system according to the present invention may be an outer frame that stabilizes the container, which can be designed from a metal profile in the form of a frame structure and surrounds and supports the container. The frame structure may have an open design with a cover, side walls, and a door for easy access during operation and maintenance work. This allows access to the cooling system at the local site.

[0025] In an advantageous embodiment, a pick-and-place system can be installed to transport the electronic component from the locking device to the working position for replacement. This pick-and-place system may consist of a robotic arm or a linear drive. If the device is properly constructed, the component replacement can be performed by a fully automated pick-and-place system. Alternatively, a glove can be placed at a suitable container opening to replace the electronic component from the locking device to the working position. This allows for placement by manual access to the inside of the container.

[0026] In a preferred embodiment of the present invention, the supply line, return line, and / or outlet may be individually or in combination with each other closable or open via valves. To ensure the process proceeds properly, the gaseous medium or liquid heat transfer fluid is further advanced by opening the individual valves as needed. Supply or discharge can be performed periodically or in continuous mode. In particular, the switching of the valve at the outlet is adjusted to minimize, or eliminate, the outflow of heat transfer fluid from the cooling system.

[0027] Advantageously, the second condenser unit may be heatable. This operating mode allows for a short heating of the residual gas phase, consisting of water vapor and air, to equalize the pressure. In this operating mode, the condensed heat transfer fluid is in the second return line. Due to some positive pressure or gravity, the liquid heat transfer fluid can return to the container. The heating, and the associated pressure equalization relative to the ambient air or positive pressure, allows for easy discharge of the residual gas. If there is some positive pressure relative to the ambient air, outside air will not enter the cooling system in the reverse direction through the outlet.

[0028] In an advantageous embodiment of the present invention, a collection container can be placed downstream of the outlet, and the residual gas phase can be discharged through this collection container. This container is also used to prevent ambient air from entering the cooling system. The container may be an inflatable elastic balloon or a bellows with a variable volume.

[0029] Advantageously, a drying unit can be placed between the outlet and the collection container to separate water vapor from the gas phase. For example, when the load changes, the pressure state of the entire cooling system changes. If necessary, the collection container can introduce outside air or residual gas into the cooling system via the drying unit to equalize the pressure. The water vapor is then chemically reacted by the drying unit. Silica gel is suitable for this type of drying unit. A more advantageous location for the drying unit may be within the first and / or second condenser, including its supply line or return line.

[0030] In an advantageous embodiment of the present invention, a vacuum pump can be placed downstream of the outlet, and the residual gas phase can be discharged through this vacuum pump. In this case, since the vacuum pump always ensures that the residual gas flows outward, the residual gas phase, consisting of water vapor and air, can have negative pressure relative to the surroundings at the outlet.

[0031] Advantageously, the first condenser unit can have higher cooling performance than the second condenser unit. For example, the cooling performance of the first condenser unit is at least three times, and more preferably at least five times, that of the second condenser unit. Thus, most of the heat transfer fluid is already separated in the first condenser unit, and the air / water vapor component sent to the second condenser unit becomes abundant in the gas phase.

[0032] Advantageously, the heat exchanger and the first condenser unit can have a common first supply unit for the first single-phase heat transfer medium for cooling. Thus, the two units are at a uniform temperature level suitable for the separation process of the heat exchange fluid.

[0033] Advantageously, the second condenser unit may have a second supply unit for a second single-phase heat transfer medium for cooling. Thus, in the second condenser unit, it is possible to set different separation temperature levels to more effectively separate individual phase components.

[0034] In an advantageous embodiment of the present invention, for cooling purposes, a second condenser unit can be designed to operate at a lower single-phase heat transfer medium temperature than that of the first condenser unit. In this case, particular consideration is given to selecting pressure and temperature conditions that do not fall below the dew point of water, thereby allowing water vapor to be retained and discharged within the residual gas phase. Within this pressure and temperature range, the second condenser unit can be optimally used.

[0035] Embodiments of the present invention will be described in more detail based on the schematic diagram in Figure 1.

[0036] Figure 1 is a schematic diagram of a cooling system 1 for immersion cooling of an electronic component 2. The cooling system 1 comprises a container 3, which can be filled with a two-phase heat transfer fluid. The two-phase heat transfer fluid is an external fluid located inside the container 3 and has a liquid heat transfer fluid portion 4 in which the electronic component 2 is immersed, and a gas chamber 5 having a gaseous heat transfer fluid portion. A heat exchanger 6 is located inside the gas chamber 5 of the container 3 to form the liquid heat transfer fluid 4.

[0037] In this advantageous embodiment, the heat exchanger 6 in the gas chamber 5 consists of a tube bundle 61, and each tube bundle 61 has a plurality of heat exchange tubes arranged parallel to each other.

[0038] In the embodiment shown in the figure, the container 3 has a slightly narrowed region for the liquid heat transfer fluid 4, as the container wall protrudes inward and only opens within the gas chamber 5. The shape of the container 3 is supported by a metal profile frame 31. Thus, the container 3 is already surrounded by a stable outer frame.

[0039] The first condenser unit 7 is located outside the container 3, above it. The first condenser unit 7 is connected to the gas chamber 5 of the container 3 by a first supply line 71 to exchange a gaseous medium. Similarly, a first return line 72 for the liquefied heat transfer fluid to the container 3 is also provided, through which gravity-driven liquid heat transfer fluid returns from the first condenser unit 7 to the container 3. To control the exchange of mass, a valve 710 is fitted to the first supply line 71 and a valve 720 is fitted to the first return line 72. Thus, a gaseous mixture consisting of heat transfer fluid, air, and water vapor is periodically or continuously withdrawn from the container 3 via the valve 710 of the first supply line 71. Only the liquid heat transfer fluid is returned to the container 3 via the valve 720 of the first return line 72.

[0040] The gaseous mixture remaining in the first condenser unit 7 is supplied to the second condenser unit 8, which is connected to the first condenser unit 7 by a second supply line 81. Here again, a valve 810 attached to the second supply line controls the flow of gas. A second return line 82 for the further condensed heat transfer fluid is connected directly from the second condenser unit 8 to the container 3. The reflux of the condensed water formed in the second condenser unit 8 is controlled by a valve 820 attached to the second return line 82. After the heat transfer fluid has almost completely condensed, the remaining residual gas phase, consisting only of air and water vapor, is discharged to the outside through the outlet 83 by an outlet valve 830. To further separate the water vapor, a drying unit 11 is placed between the outlet 83 and the collection container 9 to separate the water vapor from the gas phase.

[0041] Depending on the pressure conditions, the residual gas phase can be directly discharged to the surroundings. This can be done by a heating device in the second condenser unit 8, which adjusts the pressure conditions relative to the surroundings when the valve is properly controlled.

[0042] However, alternatively, the residual gas phase can also be discharged by a vacuum pump 10. For this purpose, the outlet 83 is connected to the vacuum pump 10 via a supply line 101, and the vacuum pump 10 controls the flow of residual gas to the outside using a valve control 1010 with respect to the discharge line 102 of the vacuum pump 10.

[0043] Alternatively or additionally, the residual gas phase may also be supplied to a collection container 9 via a supply line 91 having a valve 910, which may be designed to generate negative pressure as a bellows with expandable volume. If the valve 910 to the collection container 9 is closed during operation, the residual gas can be discharged via a discharge line 92 of the collection container 9 when the valve 920 is open. [Explanation of symbols]

[0044] 1. Cooling System 2 Electronic Components 3 containers 31 Metal Profile Frames 4. Liquid heat transfer fluid 41. Liquid fluid surface inside the container 5. Gaseous heat transfer fluid, gas chamber 6 Heat exchanger 61 Tube bundles 7. First condenser unit 71. First supply line 710 Valve of the first supply line 72 First return line 720 Valve for the first return line 8. Second condenser unit 81 Second supply line 810 Valve for the second supply line 82 Second return line 820 Valve for the second return line 83 Exit 830 Outlet valve 9. Collection containers, bellows 91 Collection container supply line 910 Valve in the collection container supply line 92 Collection container discharge line 920 Valve in the discharge line of the collection container 10 Vacuum pump 101 Vacuum pump supply line 1010 Valve in the supply line of a vacuum pump 102 Vacuum pump discharge line 11 Drying Unit

Claims

1. A cooling system for immersion cooling of electronic components, - A container is provided, the interior of which can be filled with a two-phase heat transfer fluid in which electronic components can be immersed in the liquid phase, and the container has a gas chamber above the surface of the liquid heat transfer fluid. - In order to form the liquid heat transfer fluid, a heat exchanger is provided in the gas chamber of the container, - The system comprises a first condenser unit located outside the container, the first condenser unit being connected by a first supply line to the gas chamber of the container for substance exchange of a gaseous medium, and having a first return line for the condensed heat transfer fluid to the container. In a cooling system, - A second condenser unit is provided, which is connected to the first condenser unit via a second supply line to exchange the gaseous medium, and has a second return line for the condensed heat transfer fluid to the container. - The second condenser unit has an outlet from which residual gas phase can be discharged. A cooling system characterized by the following features.

2. The cooling system according to claim 1, characterized in that the supply line, the return line and / or the outlet can be closed or opened individually or in combination with each other via valves.

3. The cooling system according to claim 1, characterized in that the second condensing device unit is heatable.

4. The cooling system according to claim 1, characterized in that a collection container is located downstream of the outlet, and the residual gas phase can be discharged through the collection container.

5. The cooling system according to claim 4, characterized in that a drying unit is placed between the outlet and the collection container to separate water vapor from the gas phase.

6. The cooling system according to claim 1, characterized in that a vacuum pump is located downstream of the outlet, and the residual gas phase can be discharged via the vacuum pump.

7. The cooling system according to claim 1, characterized in that the first condenser unit has higher cooling performance than the second condenser unit.

8. The cooling system according to claim 1, characterized in that the heat exchanger and the first condenser unit have a common first supply unit for a first single-phase heat transfer medium for cooling.

9. The cooling system according to claim 8, characterized in that the second condensing device unit has a second supply unit for a second single-phase heat transfer medium for cooling.

10. The cooling system according to claim 9, characterized in that the second condenser unit is designed to operate at a lower temperature of the single-phase heat transfer medium than the first condenser unit for cooling purposes.

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