Cooling device for a system for cooling electronic devices, and cooling method

Abstract

The invention relates to a cooling device (10) for a system (1) for cooling electronic components (5) partially immersed in a dielectric fluid (7), comprising a first heat exchanger (11). Said first exchanger (11) is configured to be partially immersed in the dielectric fluid (7) and comprises a first circuit for a first heat-transfer fluid, and characterized in that the cooling device (10) comprises a second heat exchanger (13) configured to be in contact with a part of the electronic components (5), said second exchanger (13) being fluidically connected to the first exchanger (11) in such a way that the first exchanger (11) and the second exchanger (13) together form a second circuit for a second heat-transfer fluid.

Description

Description Title: Cooling Device for a Cooling System for Electronic Devices and Cooling Method [1] The present invention relates to a cooling device and a cooling system for electronic devices. The present invention also relates to a method for cooling an electronic device. [2] Servers used for data processing (commonly referred to as information technology or "IT") generally consist of printed circuit boards (PCBs) on which electronic components such as integrated circuits are mounted. These components may include central processing units (CPUs), random access memory (RAM), etc. All these electronic components or devices generate heat when in use. In order to maintain the contents at an optimal temperature to maximize computer performance, it is essential to dissipate the heat generated and / or cool the components involved. [3] In general, the electronic components or devices used in servers are air-cooled. A heat sink with fins or similar elements is typically used to dissipate heat into the surrounding air. This heat sink is then placed in contact with the surface of the electronic chip. This contact can be direct or achieved through a thermal interface material between the two components. In addition to the heat sink, one or more fans may be used to circulate air and remove heat from the heat sink. Such a heat sink can be used in combination with cooling on the server side of the installation, such as air conditioning. However, this cooling method is not particularly efficient.It also has a high operating cost and requires very large spaces to manage the air used for cooling. [4] Liquid cooling is an alternative to air cooling. In some cases, liquid cooling allows for more efficient heat transfer from electronic components or devices, and therefore greater Cooling capacity. These liquids include, for example, dielectric fluids, mineral oil, or water. Liquids with a high specific heat capacity are particularly advantageous. [5] One of the aims of the present invention is therefore to propose a cooling device and a cooling system for electronic devices which allows the cooling power to be adapted according to each of the components to be cooled and which also facilitates the circuit of the heat fluids intended to circulate within the cooling device. [6] To this end, the invention relates to a cooling device for a cooling system of electronic components partially immersed in a dielectric fluid comprising a first heat exchanger, the cooling device being characterized in that the first heat exchanger, in particular a plate heat exchanger, is configured to be partially immersed in the dielectric fluid, said first heat exchanger comprising a first circuit for a first heat transfer fluid, and characterized in that the cooling device comprises a second heat exchanger configured to be in contact with a part of the electronic components, said second heat exchanger being fluidly connected to the first heat exchanger so that the first heat exchanger and the second heat exchanger together form a second circuit for a second heat transfer fluid. [7] Such a cooling device makes it possible to cool several separate components or circuits from a single source, thus simplifying the circuit. Furthermore, the cooling power can be adapted to each component being cooled. [8] According to one exemplary embodiment, the first heat exchanger further comprises a cooling plate configured to be immersed in the dielectric fluid and thermally coupled to the first heat exchanger so that the heat produced by the immersed electrical components and transferred via the dielectric fluid to the cooling plate can be removed via the first heat exchanger. [9] According to one embodiment, the first circuit for the first heat transfer fluid includes a fluidic connection between the first heat exchanger of heat and the cooling plate. Furthermore, the cooling plate includes part of the first circuit for the first heat transfer fluid so that the first heat transfer fluid can circulate inside the cooling plate.

[0010] According to one embodiment, the fluidic connection between the first heat exchanger and the cooling plate is arranged inside the first heat exchanger and the cooling plate.

[0011] According to another embodiment, the fluidic connection is located outside of said first heat exchanger and cooling plate.

[0012] According to one embodiment, the second heat exchanger includes at least one extension with one end configured to be immersed in the dielectric fluid contained in the receptacle.

[0013] In addition, a mounting interface can be attached to the first heat exchanger.

[0014] Furthermore, the cooling plate can be attached to this mounting interface.

[0015] According to another embodiment example, a thermal interface is arranged between the first heat exchanger and the cooling plate.

[0016] According to an example of implementation, the first heat exchanger and / or the second heat exchanger is / are manufactured by additive manufacturing.

[0017] The invention also relates to a cooling system using such a cooling device, particularly for cooling computer servers. However, this cooling system can be applied to cooling other electronic components and devices.

[0018] According to one embodiment, the cooling system includes a receptacle for holding electronic devices and / or electronic components and dielectric fluid; and the electronic devices and electronic components are intended to be immersed in the dielectric fluid and the cooling system includes a cooling device as described above, the first heat exchanger of said cooling device being intended to be immersed at least partially in the dielectric fluid contained in the receptacle.

[0019] According to another embodiment, the cooling system includes a means for moving a fluid, such as a pump or propeller arranged inside the receptacle.

[0020] Furthermore, said means of movement is configured to circulate the dielectric fluid contained in the receptacle.

[0021] Furthermore, the said means of movement is notably immersed in the dielectric fluid contained in the receptacle.

[0022] According to another embodiment, the second heat exchanger of the cooling device is coupled to at least one of the electronic components intended to be immersed in the dielectric fluid.

[0023] The invention also relates to a method for cooling an electronic device which comprises the following steps: - evaporation of the second heat transfer fluid within a second heat exchanger; - condensation of the second heat transfer fluid within the first heat exchanger.

[0024] According to one variant, the cooling process further includes an additional step in which there is a circulation of the first heat transfer fluid within the cooling plate immersed in the dielectric fluid, the cooling plate being thermally coupled to the first heat exchanger so that a heat transfer takes place between the first heat transfer fluid and the dielectric fluid.

[0025] According to one variant, there is a circulation of the second heat transfer fluid within the extension of the second heat exchanger, one end of the extension bathed in the dielectric fluid.

[0026] According to one variant, the cooling process further includes an additional step in which the dielectric fluid circulates around a set of electronic components in order to cool them by bubbling.

[0027] Other advantages and characteristics will appear on reading the description of several illustrative but non-limiting examples of the present invention, as well as the appended drawings in which:

[0028] Figure 1 is a schematic representation of a cooling system for an electronic device;

[0029] Figure 2 is a schematic representation of a first embodiment of a cooling device for the cooling system of Figure 1;

[0030] Figure 3 is a schematic representation of a second embodiment of a cooling device for the cooling system of Figure 1;

[0031] Figure 4 is a schematic representation of a variant of the cooling system of an electronic device in Figure 1.

[0032] In these figures, identical elements bear the same reference numbers.

[0033] The following are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference relates to the same embodiment, or that the features apply only to a single embodiment. Simple features from different embodiments can also be combined or interchanged to provide other embodiments.

[0034] In this description, certain elements or parameters can be indexed, such as first element or second element, first parameter and second parameter, first criterion and second criterion, and so on. In this case, it is simply indexing to differentiate and name similar but not identical elements, parameters, or criteria. This indexing does not imply any priority of one element, parameter, or criterion over another, and such designations can easily be interchanged without departing from the scope of this description. Nor does this indexing imply any order in time, for example, for evaluating one criterion over another.

[0035] We will first turn to Figure 1, which schematically illustrates a cooling system 1 for electronic components 5. This cooling system 1 includes a receptacle 3 intended to hold electronic devices 5 and / or electronic components 5, as well as dielectric fluid 7. The electronic devices 5 and electronic components 5, which tend to emit heat during their in operation, they are immersed in the dielectric fluid 7 in order to be cooled by it.

[0036] Electronic components include, for example, computer components such as graphics processing units (GPUs), central processing units (CPUs), and switching components. These electronic components are generally used in servers within a data center. Because these components are very small, a large number of them can be arranged within servers. However, this compact arrangement means that each component generates a greater amount of heat that needs to be dissipated efficiently. Furthermore, cooling requirements can vary from one type of electronic component to another.

[0037] At the heart of the cooling system 1 is a cooling device 10 comprising a first heat exchanger 11. This first heat exchanger 11 is, in particular, a plate heat exchanger that is partially immersed in the dielectric fluid 7. This first heat exchanger 11 includes a first circuit for a first heat transfer fluid. This first heat transfer fluid may, in particular, be in the form of a water-based coolant, a dielectric fluid, or a refrigerant.

[0038] The cooling device 10 further includes a second heat exchanger 13 configured to be in contact with a part of the electronic components 5. The second heat exchanger 13 is fluidly connected to the first heat exchanger 11 so that the first heat exchanger 11 and the second heat exchanger 13 together form a second circuit for a second heat transfer fluid.

[0039] This second heat transfer fluid can notably be in the form of a two-phase fluid. The second heat transfer fluid therefore undergoes a change of state during its circulation in the second circuit. More specifically, the second two-phase heat transfer fluid can evaporate inside the second heat exchanger 13, meaning that at least part of the second heat transfer fluid changes from a liquid to a gaseous state, while this same second two-phase heat transfer fluid can undergo condensation. inside the first heat exchanger 11, that is to say that at least part of the second heat transfer fluid changes from the gaseous state to the liquid state.

[0040] More specifically, the stacking of the plates in the first heat exchanger 11 delimits on the one hand at least part of the first circuit for the first heat transfer fluid and on the other hand at least part of the second circuit for the second heat transfer fluid, this is illustrated in particular in figures 2 and 3.

[0041] In these figures, the circulation of the first heat transfer fluid in the first circuit, partially delimited by the first heat exchanger 11, is represented by solid arrows, while the circulation of the second heat transfer fluid in the second circuit, also partially delimited by the first heat exchanger 11, is represented by dashed arrows. Therefore, there is heat exchange between the first and second heat transfer fluids at the stack of plates in this first heat exchanger 11.

[0042] The second heat transfer fluid therefore circulates on the one hand in the part of the second circuit partially delimited by the first heat exchanger 11 where the second heat transfer fluid undergoes heat exchange with the first heat transfer fluid, and on the other hand it circulates in the part of the second circuit partially delimited by the second heat exchanger 13. Furthermore, the second heat exchanger 13 is configured to be thermally coupled to an electronic device comprising electronic components 5 immersed in the dielectric fluid 7. Thus, the second heat exchanger 13 serves to remove the heat emitted by the electronic components 5 of the electronic device to which it is coupled.

[0043] Optionally, the cooling device 10 may include a cooling plate 15 immersed in the dielectric fluid 7. This cooling plate 15 is then thermally coupled to the first heat exchanger 11 so that the heat produced by the immersed electrical components 5 and transferred via the dielectric fluid 7 to the cooling plate 15 can be dissipated through the first heat exchanger 11. Such a cooling plate allows for further control of the temperature of the dielectric fluid 7 contained in the receptacle 3.

[0044] Generally, the surface area of ​​the cooling plate 15 is between 40% and 80% of the surface area inside the receptacle 3. According to one embodiment, the surface area of ​​the cooling plate 15 corresponds to 60% of the surface area inside the receptacle 3.

[0045] The cooling plate 15 can be attached to the first heat exchanger 11 by brazing. Such an attachment of the cooling plate 15 to the first heat exchanger 11 can strengthen the structure of the cooling device 10. This also ensures the sealing of the cooling device 10.

[0046] In another embodiment, a mounting interface can be fixed to the first heat exchanger 11. The cooling plate 15 is then fixed to this mounting interface. Using a mounting plate between the heat exchanger and the cooling plate 15 allows for greater flexibility in the arrangement of the heat exchanger and the cooling plate 15.

[0047] Other means of fixing the cooling plate 15 to the first heat exchanger 11 can be considered.

[0048] According to a first embodiment, the first circuit for the first heat transfer fluid includes a fluid connection 17 between the first heat exchanger 11 and the cooling plate 15. In this first embodiment, the cooling plate 15 incorporates part of the first circuit for the first heat transfer fluid, allowing the first heat transfer fluid to circulate within the cooling plate. This is illustrated by the solid arrows in Figures 2 and 3. Therefore, in this first embodiment, heat exchange occurs between the first heat transfer fluid and the dielectric fluid 7 via the cooling plate 15.

[0049] In this same embodiment, the fluid connection 17 between the first heat exchanger 11 and the cooling plate 15 is arranged inside the first heat exchanger 11 and the cooling plate 15 to allow the circulation of the first heat transfer fluid between these two elements. This embodiment is illustrated in particular in Figures 2 and 3.

[0050] As illustrated in Figures 2 and 3, the fluidic connection 17 includes, in particular, an inlet 18 and an outlet 19. The inlet 18 allows the circulation of first heat transfer fluid from the first heat exchanger 11 to the cooling plate 15 while outlet 19 allows circulation of the first heat transfer fluid from the cooling plate 15 to the first heat exchanger 11.

[0051] The first circuit therefore allows the first heat transfer fluid to circulate within the first heat exchanger 11 to ensure heat exchange with the second heat transfer fluid, and also inside the cooling plate 15 to allow cooling of the dielectric fluid 7 in which the cooling plate 15 is immersed.

[0052] In the first variant of this first embodiment illustrated in Figure 2, the fluidic connection 17 is arranged inside said first heat exchanger 11 and the cooling plate 15. This variant has the advantage of being very compact.

[0053] In the second variant of this first embodiment illustrated in Figure 3, the fluidic connection 17 is located outside the first heat exchanger 11 and the cooling plate. This variant has the advantage of being easier to manufacture than the first variant described above.

[0054] In some embodiments, the heat transfer fluid circuit in said cooling plate 15 has at least two passes, and a bypass device, active or passive, forming a fluid connection between the two passes, the bypass device being configured to open or close the connection between the two passes so as to reduce the fluid circuit by bypassing a part of said circuit.

[0055] Advantageously, the heat exchange surface area of ​​the cooling plate 15 can be minimized or not, thereby modulating the power output. In other words, the idea is to restrict fluid circulation in a portion of the plate to avoid over-cooling the splash bath.

[0056] According to a second embodiment, there is no circulation of the first heat transfer fluid inside the cooling plate 15: only conduction creates a temperature gradient within the cooling plate 15 so that it can cool the dielectric fluid 7 in which it is immersed. This second embodiment notably allows for to eliminate the presence of a fluidic connection 17 between the first heat exchanger 11 and the cooling plate 15, which can simplify the circuit.

[0057] In this second embodiment, a thermal interface can be arranged between the first heat exchanger 11 and the cooling plate 15. This embodiment is not shown in the figures. This thermal interface can be made of graphite and / or thermal paste. Using such a thermal interface between the heat exchanger and the cooling plate 15 increases heat transfer and thus reduces heat loss. Other types of thermal interfaces can be considered.

[0058] Common to all the embodiments presented above, the first heat exchanger 11 and / or the second heat exchanger 13 can be manufactured by additive manufacturing. Additive manufacturing allows for the easy addition of surface extensions to the first heat exchanger 11 and / or the second heat exchanger 13. In general, additive manufacturing offers greater freedom in part design and allows for the creation of complex shapes.

[0059] According to another embodiment illustrated in particular in Figure 4, the second heat exchanger 13 of the cooling device 10 is coupled to at least one of the electronic components 5 intended to be immersed in the dielectric fluid 7. In this specific embodiment, the second heat exchanger 13 comprises at least one extension 21 with an end 23 which is also immersed in the dielectric fluid 7 contained in the receptacle 3. This extension 21 is cooled by the second heat transfer fluid which circulates inside the second heat exchanger 13. The end 23 of this extension 21 which is immersed in the dielectric fluid 7 thus also cools the dielectric fluid 7 contained in the receptacle 3.

[0060] In a first variant of this specific embodiment, the extension 21 is cooled by conduction with the body of the second heat exchanger 13. In a second variant of this specific embodiment, the circuit of the second heat transfer fluid passes through this extension 21 at least partially immersed in the dielectric fluid 7 contained in the receptacle 3.

[0061] A method for cooling an electronic device using a cooling system 1 with a cooling device 10 according to one The implementation methods presented above include, in particular, the following steps: - - evaporation of the second heat transfer fluid within a second heat exchanger (13); - condensation of the second heat transfer fluid within the first heat exchanger 11.

[0062] This method allows for the cooling of multiple components from a single source, thus simplifying the circuit. Furthermore, the cooling power can be adjusted according to the needs of each individual component.

[0063] This process may further include an additional step in which the first heat transfer fluid circulates in a liquid state within the cooling plate 15 immersed in the dielectric fluid, the cooling plate 15 being thermally coupled to the first heat exchanger. 11 so that heat transfer takes place between the first heat transfer fluid and the dielectric fluid.

[0064] An active circulation of the first heat transfer fluid in liquid form within the cooling plate 15 immersed in the dielectric fluid 7 promotes heat exchange between the cooling plate 15 and the dielectric fluid 7 contained in the receptacle 3 of the cooling system 1, thus enabling efficient cooling of the electronic components 5 which are immersed in this same dielectric fluid 7.

[0065] This process may further include an additional step in which there is a circulation of the second heat transfer fluid within the extension 21 of the second heat exchanger 13, an end 23 of the extension 21 being immersed in the dielectric fluid 7. An active circulation of the second heat transfer fluid within the extension 21 of the second heat exchanger 13 promotes the heat exchange between the end 23 of the extension 21 and the dielectric fluid 7 contained in the receptacle 3 of the cooling system 1, thus enabling the efficient cooling of the electronic components 5 which are immersed in this same dielectric fluid.

[0066] This process may also include an additional step in which the dielectric fluid 7 circulates around a set of electronic components 5 to cool them by bubbling. This circulation of the dielectric fluid 7 around the components contained in the receptacle 3 may be active, or it may be passive.

[0067] Active circulation of the dielectric fluid 7 around the electronic components 5 contained in the receptacle, for example by means of a means of moving said dielectric fluid 8, promotes heat exchange and homogenizes the temperature within the dielectric fluid, thus contributing to the regulation of heat rejection by the electronic components.

[0068] Thus, in order to homogenize the temperature of the dielectric fluid 7 in which the electronic components 5 are immersed, the cooling system 1 may include a means for setting the dielectric fluid 7 in motion 8. Such a means for setting the dielectric fluid 7 in motion 8 is illustrated in Figure 4. This means for setting the dielectric fluid 7 in motion 8 is configured to circulate the dielectric fluid 7 contained in the receptacle 3 so that it flows around the electronic components 5 contained in the same receptacle 3. This circulation by a means for setting the dielectric fluid 8 promotes heat exchange and homogenizes the temperature within the dielectric fluid 7, thereby regulating the heat dissipation by the electronic components 5.

[0069] This drive means 8 may in particular be in the form of a pump or a propeller arranged inside the receptacle 3 which contains the dielectric fluid 7. The drive means 8 may be fixed to the receptacle 3. The drive means 8 is in particular immersed in the dielectric fluid 7 contained in the receptacle 3.

[0070] The means of actuation 8 may include a spray nozzle configured to distribute the dielectric fluid 7 over some or all of the electronic components 5. Such a spray nozzle makes it possible to reach electronic components 5 that are difficult to access.

[0071] It is therefore possible to design a cooling device and arrange a cooling system capable of cooling several components distinct while simplifying the circuit. This cooling device and cooling system also allow the cooling power to be adapted according to each of the components to be cooled.

Claims

CLAIMS

1. Cooling device (10) for a system (1) for cooling electronic components (5) partially immersed in a dielectric fluid (7) comprising a first heat exchanger (11), the cooling device (10) being characterized in that the first heat exchanger (11), in particular a plate heat exchanger, is configured to be partially immersed in the dielectric fluid (7), said first heat exchanger (11) comprising a first circuit for a first heat transfer fluid, and characterized in that the cooling device (10) comprises a second heat exchanger (13) configured to be in contact with a portion of the electronic components (5),said second heat exchanger (13) being fluidically connected to the first heat exchanger (11) such that the first heat exchanger (11) and the second heat exchanger (13) together form a second circuit for a second heat transfer fluid.,

2. Cooling device (10) according to claim 1, characterized in that the first heat exchanger (11) further comprises a cooling plate (15), said plate (15) being configured to be immersed in the dielectric fluid (7) and thermally coupled to the first heat exchanger (11) so that the heat produced by the immersed electrical components and transferred via the dielectric fluid (7) to the cooling plate (15) can be removed via the first heat exchanger (11).

3. Cooling device according to claim 2, characterized in that the first circuit for the first heat transfer fluid comprises a fluid connection (17) between the first heat exchanger (11) and the cooling plate (15) and in that the cooling plate (15) comprises a part of the first circuit for the first heat transfer fluid so that the first heat transfer fluid can circulate inside the cooling plate (15).

4. Cooling device according to the preceding claim, characterized in that the fluid connection (17) between the first heat exchanger (11) and the cooling plate (15) is arranged inside the first heat exchanger (11) and the cooling plate (15).

5. Cooling device according to claim 3, characterized in that the fluid connection (17) is offset outside said first heat exchanger (11) and the cooling plate (15).

6. Cooling device according to any one of the preceding claims, characterized in that the second heat exchanger (13) comprises at least one extension (21) with one end (23) configured to bathe in the dielectric fluid (7) contained in the receptacle (3).

7. System (1) for cooling electronic components (5) comprising a receptacle (3) intended to contain electronic devices and / or electronic components (5) and dielectric fluid, the electronic devices and the electronic components (5) being intended to bathe in the dielectric fluid (7); and a cooling device (10) according to any one of the preceding claims, the first heat exchanger (11) of said cooling device (10) being intended to bathe at least partially in the dielectric fluid (7) contained in the receptacle (3).

8. Cooling system (1) according to claim 7, characterized in that it comprises a means (8) for setting in motion a fluid, such as a pump or a propeller arranged inside the receptacle (3) and in that said means (8) for setting in motion is configured to set in motion the dielectric fluid (7) contained in the receptacle (3), said means (8) for setting in motion being in particular immersed in the dielectric fluid (7) contained in the receptacle (3).

9. Cooling system (1) according to any one of claims 7 to 8, characterized in that the second heat exchanger (13) of the cooling device (10) is coupled to at least one of the electronic components (5) intended to be immersed in the dielectric fluid (7).

10. Method for cooling an electronic device implemented by a cooling system according to one of claims 7 to 9, characterized in that the method comprises the following steps: - evaporation of the second heat transfer fluid within a second heat exchanger (13); - condensation of the second heat transfer fluid within the first heat exchanger (11).

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