Filtering dielectric fluid in an immersion tank

Abstract

An installation (1) comprises: - an immersion tank (3) configured to receive a dielectric fluid (4) and computer devices (2) immersed in the dielectric fluid (4); - a filter tank (12) comprising a first compartment (22) and a second compartment (23) separated by a central wall (24), an opening (25) being formed in the central wall (24) so ​​as to put the first compartment (22) and the second compartment (23) into fluid communication; - means for supplying the dielectric fluid (4) from the immersion tank (3) to the first compartment (22) of the filter tank (12); - a pump (10) configured to suck fluid into the second compartment (23); and - a filter (26) mounted in the opening (25) of the central wall (24) to filter the dielectric fluid (4) which flows towards the second compartment (23). Figure for abstract: Fig. 2

Description

Title of the invention: Filtering of dielectric fluid in an immersion tank Technical field

[0001] The present invention relates to the general technical field of immersion cooling of computer devices such as computer servers. STATE OF THE ART

[0002] Immersion cooling is an innovative cooling technology for computing devices that offers significant advantages over traditional air cooling methods. Immersion cooling involves immersing computing devices, typically computer servers, in immersion tanks forming a bath of dielectric heat transfer fluid.

[0003] This passive cooling process is very efficient. Compared to air or water cooling, immersion cooling can drastically reduce cooling energy consumption.

[0004] The dielectric fluid is chosen so as to maximize the immersion cooling capacity. The dielectric fluid may, for example, comprise a synthetic hydrocarbon-based fluid. However, the alkanes present in these fluids degrade plastic materials and therefore reduce the service life of the cables. In addition to harming the proper functioning of the submerged computing devices, the degradation of the cables has the effect of generating waste which is likely to damage the cooling circuit.

[0005] The computer devices are therefore positioned in the immersion tank so as to minimize the cable surface in contact with the fluid. A pump placed in the upper part of the immersion tank regulates the height of the fluid to limit these contacts. The sucked fluid is also filtered in order to recover pieces of plastic and other particles present in the fluid. However, in use, it remains necessary to clean the filter very regularly to avoid any risk of damage to the electronic components of the computer devices and to protect the cooling circuit. However, the filters are generally difficult to access and their maintenance requires the operator to dismantle part of the installation and immerse his hands in the dielectric fluid, which leads to operational costs and downtime affecting the availability of the computer devices. Statement of the invention

[0006] An aim of the present application is to remedy the aforementioned drawbacks. More specifically, an aim of the present invention is to propose an installation for the immersion cooling of computer devices, such as computer servers, the maintenance of which is facilitated.

[0007] To this end, according to a first aspect, an installation is proposed comprising: - an immersion tank configured to receive a dielectric fluid and comprising retaining means configured to receive computer devices so that the computer devices are immersed in the dielectric fluid; - a filter tank comprising a first compartment and a second compartment separated by a central wall, an opening being formed in the central wall so as to put the first compartment and the second compartment into fluid communication; - means for supplying the dielectric fluid from the immersion tank to the first compartment of the filter tank; - a pump configured to draw fluid into the second compartment of the filter tank; and - a filter mounted in the opening of the central wall to filter the dielectric fluid which flows towards the second compartment.

[0008] Some preferred but non-limiting features of the installation according to the first aspect are the following, taken individually or in combination: - when the installation is placed on a floor, the first compartment is placed above the second compartment so that the dielectric fluid flows by gravity from the first compartment to the second compartment; - the filter has a cover which extends into the first compartment and a gripping member which projects from the cover; - the gripping member comprises a rod extending from the cover in an opposite direction relative to the second compartment and a handle attached to the end of the rod; - when the filter is mounted in the opening, the handle is above the surface of the dielectric fluid; - the central wall is inclined relative to a horizontal plane and the filter is positioned at a low point on the wall; - the filter tank is separated from the immersion tank by a separating wall and the supply means comprise a window which is formed in the separating wall so as to put the immersion tank and the filter tank into fluid communication, a level of dielectric fluid in the immersion tank being higher than a level of dielectric fluid in the filter tank so that the dielectric fluid flows out through the window into the filter tray when its level reaches a lower edge of the window; - the supply means comprise an additional pump configured to suck dielectric fluid into the immersion tank and discharge it into the first compartment of the filter tank and / or - the installation further comprises at least one computer device immersed in the dielectric fluid and mounted in the retaining means.

[0009] According to a second aspect, there is provided a data center comprising an installation according to the first aspect and computing devices mounted in the retaining means. DESCRIPTION OF FIGURES

[0010] Other characteristics, aims and advantages of the invention will emerge from the following description, which is purely illustrative and non-limiting, and which must be read in conjunction with the appended drawings in which:

[0011] [Fig. 1] illustrates schematically and in perspective an example of an installation in accordance with one embodiment;

[0012] [Fig. 2] is a sectional view of an example of an installation according to one embodiment, in a plane passing through the filter tank;

[0013] [Fig.3] is a top view of the installation example of [Fig.2]; and

[0014] Fig. 4 is a sectional view of the installation example of [Fig.2], in a plan passing through computer devices.

[0015] Throughout the figures, similar elements bear identical references. DETAILED DESCRIPTION OF THE INVENTION

[0016] An installation 1 for the immersion cooling of computer devices 2, such as computer servers, comprises an immersion tank 3 filled with a dielectric fluid 4 and non-corrosive in which the computer devices 2 are immersed, and a system for cooling the dielectric fluid 4.

[0017] The immersion tank 3 comprises a bottom wall 5 configured to be placed on a generally horizontal support (for example the ground), side walls 6, 7 which extend from the bottom wall 5, and an opening, which extends opposite the bottom wall 5. The side walls 6, 7 give the immersion tank 3 a generally rectangular cross-section. The installation 1 further comprises a cover configured to cover the opening and close the immersion tank 3.

[0018] In the following, the invention will be described with reference to the operating configuration of the installation 1. In particular, “upper” (respectively “top”) and “lower” (respectively “bottom”) are used with reference to the installation 1, a lower part being arranged on the side of the bottom of the immersion tank 3 while an upper part will be arranged on the side of the opening.

[0019] The immersion tank 3 comprises means 8 for retaining the computer devices 2, for example racks, mounted on two facing side walls 6, 7 and configured to hold each computer device 2 in position relative to the side wall 7. Each computer device 2 has an upper edge 9, configured to be placed facing the cover, comprising connectors configured to be connected to a network via electrical cables. Each electrical cable comprises for this purpose a terminal 28, configured to be connected on the upper edge 9 of the computer device 2 to the corresponding connector, and a cable portion 29 configured to electrically connect the terminal 28 to the computer network. The retaining means 8 are furthermore positioned so that, in use, the upper edge 9 of the computer devices 2 is immersed in the dielectric fluid 4.

[0020] The dielectric fluid 4 may comprise a synthetic hydrocarbon-based fluid, for example isoparaphine. Such a dielectric fluid 4 is in fact non-corrosive and has a thermal conductivity of approximately 0.137 W / km at 25°C, i.e. almost six times that of air. The function of the dielectric fluid 4 is to absorb the heat generated by the computer devices 2 which are immersed. It is continuously cooled by a cooling system comprising a pump 10 configured to suck in the dielectric fluid 4 and discharge it into a heat exchanger 11, where it is cooled before being discharged into the immersion tank 3.

[0021] In one embodiment, the cooling system comprises two cooling circuits each comprising a pump 10 and a heat exchanger 11, so as to ensure the cooling of the dielectric fluid 4, even in the event of failure of one of the components. In this embodiment, only one of the cooling circuits is operated at a time, the other cooling circuit being redundant.

[0022] In order to facilitate the maintenance of the installation 1, the latter further comprises: - a filtering tank 12 comprising a first compartment 22 and a second compartment 23 separated by a central wall 24, an opening 25 being formed in the central wall 24 so as to put the first compartment 22 and the second compartment 23 into fluid communication; - means for supplying the dielectric fluid 4 from the immersion tank 3 to the first compartment 22 of the filter tank 12; and - a filter 26 mounted in the opening 25 of the central wall 24.

[0023] In addition, the pump 10 is connected to a suction orifice 32 which opens into the lower compartment 23 in order to suck up the dielectric fluid after it has passed through the filter 26.

[0024] The lower compartment 23 preferably extends below the upper compartment 22 so that the lower compartment 23 and the upper compartment 22 are therefore stacked one above the other along the vertical axis so that the dielectric fluid 4 passes through the filter 26 and flows into the lower compartment 23 by gravity. The volume of the lower compartment 23 may be greater than the volume of the upper compartment 22 so that it serves as a reservoir for the dielectric fluid 4.

[0025] The filter tank 12 further has a bottom wall 20, side walls 21, 7 extending from the bottom wall 20 and an opening. Furthermore, the cover of the installation 1 is configured to also cover the opening of the filter tank 12.

[0026] This configuration thus makes it easier to maintain the filter 26. In fact, the filter 26 is easily accessible and removable from the opening of the filtering tank 12, without requiring the dismantling of a part of the installation 1.

[0027] In one embodiment, the filter 26 comprises a body 28 which is inserted into the opening 25 and a cover 29 which extends into the upper compartment 22. To further facilitate maintenance, the filter 26 further comprises a gripping member which projects from the cover. The gripping member may for example comprise a rod 30 extending from the cover 29 towards the opening of the filter tank 12 as well as a handle 31 extending near an upper end of the rod. Preferably, the handle 31 is adjacent to the cover and is outside the dielectric fluid 4 when the filter 26 is inserted into the opening 25. For this purpose, the rod 30 may for example have a length substantially equal to the height of the upper compartment 22 (the height corresponding to the distance between the bottom wall 20 and the opening of the filter tank 12).In this way, an operator simply has to open the cover of the installation 1, grasp the handle 31 of the filter 26, which is easily accessible and dry thanks to the rod 30, and pull on the handle 31 to extract the filter 26.

[0028] The filter 26 may for example comprise a fine mesh stainless steel screen, typically less than or equal to 0.5 mm. For example, the filter may be a stainless steel strainer having a mesh of 0.5 mm. This type of filter is in fact easy to clean.

[0029] In order to facilitate the flow towards the lower compartment 23, the central wall 24 may be inclined relative to a horizontal plane, for example following a slope of between 1% and 5%, typically a slope of 2%. The central wall 24 is then inclined so that its lowest point corresponds to the part in which is formed the opening 25. In one embodiment, the opening 25 is formed near one of the side walls 21 of the filter tank 12 (see [Fig.4]). Alternatively, the opening 25 could be centered relative to the central wall 24, in which case the central wall 24 is substantially pyramidal.

[0030] In one embodiment, the suction orifice 32 extends in a lower zone of one of the side walls 21, 7, and the bottom wall 20 of the filter tank 12 is inclined towards the suction orifice 32, for example with a slope of the order of 1%. The dielectric fluid 4 is therefore already filtered by the filter 26 when it is sucked in by the pump 10. The pump 10 delivers the filtered dielectric fluid 4 and sends it to the heat exchanger 11, for example of the 50 kW to 100 kW oil / water exchanger type in order to obtain a temperature difference of at least 13°C between the inlet and the outlet of the dielectric fluid 4, knowing that the maximum target operating temperature of the dielectric fluid 4 is 60°C. The temperature of the dielectric fluid 4 entering the heat exchanger 11 can be between 30°C and 45°C, and its outlet temperature can be between 45°C and 60°C (depending on the external weather conditions).The temperature of the cold water entering the heat exchanger 11 is preferably less than or equal to 40°C (30°C in winter) and the outlet temperature, after heat exchange with the dielectric fluid 4, may be of the order of 45°C to 55°C. Once cooled, the dielectric fluid 4 is returned to the immersion tank 3, preferably through orifices formed near the bottom wall 5, typically in the bottom wall 5 or in the lower part of the side walls 6. In this way, the cooled dielectric fluid 4 rises naturally by convection along the computer devices 2, which it cools by heat transfer. The dielectric fluid 4 is therefore gradually heated by the computer devices 2 until it reaches the surface of the immersion tank 3.

[0031] In one embodiment, the means for supplying the dielectric fluid 4 comprise an additional pump configured to suck up hot dielectric fluid 4 from the upper part of the immersion tank 3, and deliver it into the upper compartment 22 of the filtering tank 12. The filtering tank 12 can therefore be contiguous to the immersion tank 3 or extend at a distance from the immersion tank 3, depending on the configuration of the pipes connecting the additional pump to the tanks 3 and 12.

[0032] In another embodiment, which is illustrated in the figures, the means for supplying the dielectric fluid may be passive and operate by overflow. For this, the filter tank 12 is placed in the immediate vicinity of the immersion tank 3 in the installation 1 so that the filter tank 12 and the immersion tank share a common wall 7. The filter tank 12 may, for example, extend along the entire length of the immersion tank 3. The filter tank 12 and the immersion tank 3 are therefore part of the same tank and are simply separated by the common wall 7. In addition, a window 13 is formed in the common wall 7 in order to put the immersion tank 3 and the filter tank 12 into fluid communication. The window 13 has a lower edge 14 (bottom side), an upper edge (lid side) which are connected by lateral edges. Finally, the level of dielectric fluid 4 in the immersion tank 3 is higher than the level of fluid 3 in the filter tank 12 so that the dielectric fluid 4 pours through the window 13 into the filter tank 12 when its level reaches the lower edge 14 of the window 13.

[0033] By fluid level 3, we will understand here the distance, measured along an axis normal to the horizontal support, between the support and the surface of the fluid 3.

[0034] The adjustment of the fluid level 3 in the immersion tank 3 is therefore passive and dictated by the position of the lower edge 14 of the window 13. Indeed, as soon as the fluid level 3 reaches the lower edge 14 of the window, the excess dielectric fluid 4 overflows and flows automatically into the filter tank 12, thus guaranteeing a stable and controlled fluid level 3 in the immersion tank 3.

[0035] The window 13 may extend over all or part of the length of the common wall 7. By length, here we mean the dimension of the common wall 7 in a plane parallel to the ground between the two side walls 6 which are connected to the common wall 7. Alternatively, the window 13 may be segmented and be formed of several disjointed window segments 13 distributed along the length of the common wall 7. This configuration in fact makes it possible to stiffen the common wall 7, while guaranteeing the ability of the windows to maintain the desired level of dielectric fluid in the immersion tank 3.

[0036] The cooling circuit(s) are preferably placed outside the immersion tank 3 and the filter tank 12. For example, all or part of the cooling circuits may be placed in a technical compartment 27, which may adjoin the filter tank 12 or be 28 at a distance from the filter tank 12. In the exemplary embodiment illustrated in FIGS. 2 to 4, the technical compartment 27 is contiguous with the immersion tank 3 and the overflow tank 12 and extends over the width and height of the tanks 3, 12. This technical compartment 27 comprises the two pumps 10, the two heat exchangers 11 and the pipes connecting the pumps 10 to the filter tank 12 and to the heat exchangers 11. This embodiment makes it possible to facilitate the maintenance of the immersion tank 3 and the overflow tank 12 by allowing easy access to the cooling circuit.

Claims

Claims

1. Installation (1) comprising: - an immersion tank (3) configured to receive a dielectric fluid (4) and comprising retaining means configured to receive computer devices (2) so that the computer devices (2) are immersed in the dielectric fluid (4); - a filter tank (12) comprising a first compartment (22) and a second compartment (23) separated by a central wall (24), an opening (25) being formed in the central wall (24) so ​​as to put the first compartment (22) and the second compartment (23) into fluid communication; - means for supplying the dielectric fluid (4) from the immersion tank (3) to the first compartment (22) of the filter tank (12); - a pump (10) configured to suck fluid into the second compartment (23) of the filter tank (12);and - a filter (26) mounted in the opening (25) of the central wall (24) for filtering the dielectric fluid (4) which flows towards the second compartment (23).;

2. Installation (1) according to claim 1, wherein, when the installation is placed on a floor, the first compartment (22) is placed above the second compartment (23) so that the dielectric fluid (4) flows by gravity from the first compartment (22) to the second compartment (23).

3. Installation (1) according to claim 2, in which the filter (26) has a cover (29) which extends into the first compartment (22) and a gripping member (30, 31) which projects from the cover (29).

4. Installation (1) according to claim 3, in which the gripping member comprises a rod (30) extending from the cover in an opposite direction relative to the second compartment (23) and a handle (31) fixed to the end of the rod (30).

5. An installation (1) according to claim 4, wherein, when the filter (26) is mounted in the opening (25), the handle (31) is above the surface of the dielectric fluid (4).

6. Installation (1) according to one of claims 1 to 5, in which the central wall (24) is inclined relative to a horizontal plane and the filter (26) is positioned at a low point of the wall (24).

7. Installation (1) according to one of claims 1 to 6, in which the filter tank (12) is separated from the immersion tank (3) by a separation wall (7) and the supply means comprise a window (13) which is formed in the separation wall (7) so as to put the immersion tank (3) and the filter tank (12) into fluid communication, a level of dielectric fluid (4) in the immersion tank (3) being higher than a level of dielectric fluid (4) in the filter tank (12) so that the dielectric fluid (4) pours through the window (13) into the filter tank (12) when its level reaches a lower edge (14) of the window (13).

8. Installation (1) according to one of claims 1 to 6, in which the supply means comprise an additional pump configured to suck dielectric fluid into the immersion tank (3) and deliver it into the first compartment (22) of the filter tank (12).

9. Installation (1) according to one of claims 1 to 8, further comprising at least one computer device (2) immersed in the dielectric fluid (4) and mounted in the retaining means (8).

10. Data center comprising an installation (1) according to one of claims 1 to 9 and computer devices (2) mounted in the retaining means (8).

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