Patent Description:
Electronic equipment, for example servers, memory banks, computer disks, and the like, is conventionally grouped in equipment racks. Large data centers and other large computing facilities may contain thousands of racks supporting thousands or even tens of thousands of servers. The racks, including equipment mounted in their backplanes, consume large amounts of electric power and generate significant amounts of heat. Cooling needs are important in such racks. Some electronic devices, such as processors, generate so much heat that they could fail within seconds in case of a lack of cooling.

Liquid cooling, in particular water cooling, has been used as an addition or replacement to traditional forced-air cooling. Cold plates, for example water blocks having internal channels for channelized water circulation, may be mounted on heat-generating components, such as processors, to displace heat from the processors toward heat exchangers. Immersion cooling (sometimes called immersive cooling) has also recently gained traction. Electronic components are inserted in a container that is fully or partially filled with a non-conducting cooling liquid, for example an oil-based dielectric cooling liquid. Efficient thermal contact is obtained between the electronic components and the dielectric cooling liquid. Immersion cooling systems commonly take the form of large tanks in which the electronic devices are submerged. Hybrid cooling systems involving both water cooling and immersion cooling have recently been introduced.

However, such cooling systems may not be efficient enough to remove enough thermal energy from the electronic device and/or may be prone to malfunctions (e.g. leakage of water within the dielectric cooling liquid). As such, a system for monitoring the cooling systems of an immersion-cooled electronic device may be desirable.

The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches.

<CIT> discloses a system for cooling electronic equipment accommodating plural electronic devices in an open space of a cooling bath provided with an inlet port and an outlet port for a liquid coolant. The cooling system is configured to directly cool the electronic devices by immersion of the electrotonic device in the liquid coolant circulated in the open space.

<CIT> discloses a sealable module adapted to be filled with a first cooling liquid and a heat transfer device having a conduction surface defining a channel for receiving a second cooling liquid. At least a portion of the conduction surface or housing is shaped in conformity with the shape of the electronic component.

<CIT> discloses an immersion server including a first surface that is exposed when the server is submerged within a cooling liquid, and at least one vapor bubble deflector physically abutting the first surface and extending away from the first surface at an angle. The deflector divides the first surface into an upper segment and a lower segment. When the server is submerged, the cooling liquid surrounding the lower segment absorbs sufficient heat to evaporate and generate vapor bubbles rising to the liquid surface. The vapor bubble deflector deflects the rising vapor bubbles away from the surface of the upper segment.

Embodiments of the present technology have been developed based on developers' appreciation of shortcomings associated with the prior art. In particular, such shortcomings may include the difficulty of detecting leaks of a channelized liquid, such as is used in water blocks, into the dielectric cooling liquid in a cooling system that uses both water blocks (or other liquid-cooled cold plates), and by immersion cooling.

The object of the invention is solved by an electronic device according to claim <NUM>. Preferred embodiments are presented in the dependent claims.

In the context of the present specification, unless expressly provided otherwise, a computer system may refer, but is not limited to, an "electronic device", an "operation system", a "system", a "computer-based system", a "controller unit", a "monitoring device", a "control device" and/or any combination thereof appropriate to the relevant task at hand.

In the context of the present specification, unless expressly provided otherwise, the expression "computer-readable medium" and "memory" are intended to include media of any nature and kind whatsoever, non-limiting examples of which include RAM, ROM, disks (CD-ROMs, DVDs, floppy disks, hard disk drives, etc.), USB keys, flash memory cards, solid state-drives, and tape drives. Still in the context of the present specification, "a" computer-readable medium and "the" computer-readable medium should not be construed as being the same computer-readable medium. To the contrary, and whenever appropriate, "a" computer-readable medium and "the" computer-readable medium may also be construed as a first computer-readable medium and a second computer-readable medium.

In the context of the present specification, unless expressly provided otherwise, the words "first", "second", "third", etc. have been used as adjectives only for the purpose of allowing for distinction between the nouns that they modify from one another, and not for the purpose of describing any particular relationship between those nouns.

Implementations of the present technology each have at least one of the above-mentioned object and/or aspects, but do not necessarily have all of them. It should be understood that some aspects of the present technology that have resulted from attempting to attain the above-mentioned object may not satisfy this object and/or may satisfy other objects not specifically recited herein.

It should also be noted that, unless otherwise explicitly specified herein, the drawings are not to scale.

The examples and conditional language recited herein are principally intended to aid the reader in understanding the principles of the present technology and not to limit its scope to such specifically recited examples and conditions. It will be appreciated that those skilled in the art may devise various arrangements that, although not explicitly described or shown herein, nonetheless embody the principles of the present technology.

Moreover, all statements herein reciting principles, aspects, and implementations of the present technology, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof, whether they are currently known or developed in the future. Thus, for example, it will be appreciated by those skilled in the art that any block diagrams herein represents conceptual views of illustrative systems embodying the principles of the present technology.

With these fundamentals in place, we will now consider some non-limiting examples to illustrate various implementations of aspects of the present disclosure.

<FIG> shows a perspective view of a rack system <NUM> for housing numerous rack-mounted assemblies <NUM>. As shown, the rack system <NUM> may include a rack frame <NUM>, rack-mounted assemblies <NUM>, a liquid cooling inlet conduit <NUM> and a liquid cooling outlet conduit <NUM>. As described more fully below, the rack-mounted assemblies <NUM> may be oriented vertically with respect to the rack frame <NUM>, resembling books on a library shelf. This arrangement may provide for mounting a large number of such rack-mounted assemblies <NUM> in the rack frame <NUM>, relative to conventional arrangements, particularly with respect to conventional arrangements of immersion-cooled rack-mounted assemblies.

<FIG> shows another perspective view of the rack system <NUM>. As shown, the rack system <NUM> may further comprise a power distribution unit <NUM> and liquid coolant inlet/outlet connectors <NUM>. It is to be noted that the rack system <NUM> may include other components such as heat exchangers, cables, pumps or the like, however, such components have been omitted from <FIG> and <FIG> for clarity of understanding. As shown in <FIG> and <FIG>, the rack frame <NUM> may include shelves <NUM> to accommodate one or more rack-mounted assemblies <NUM>. As noted above, the one or more rack-mounted assemblies <NUM> may be arranged vertically with respect to the shelves <NUM>. In some embodiments, guide members (not shown) may be used on the shelves <NUM> to guide the rack-mounted assemblies <NUM> into position during racking and de-racking, and to provide proper spacing between the rack-mounted assemblies <NUM> for racking and de-racking.

<FIG> is a schematic diagram of electronic connections of the electronic devices <NUM> (e.g. servers) hosted in the rack system <NUM>. In this embodiment, each electronic device <NUM> is electrically connected to a power distribution unit (PDU) <NUM> in parallel with one or more other electronic devices <NUM>. A plurality of PDUs <NUM> may be used to distribute electric power to all of the electronic devices <NUM> hosted in the rack system <NUM>. In this illustrative example of <FIG>, three PDUs <NUM> receive electric power from a same or different power supplies and distribute electric power to a plurality of corresponding electronic devices <NUM>.

In this embodiment, each electronic device <NUM> is electrically connected to a corresponding PDU <NUM> over a switching device <NUM> (e.g. a Solid State Relay). The switching device <NUM> is selectively closed or open to respectively disconnect and connect the electronic device <NUM> to the PDU <NUM>. Operation of the switching device <NUM> is performed by a controller <NUM> (see <FIG>) and is described in greater details herein after.

Each PDU <NUM> includes an input connector for receiving electric power from a power supply (e.g. AC power supply). The power supply may be a monophasic power supply or a multi-phasic power supply. The input connector may be, for example and without limitation, a CEE <NUM>-type plug for use in European countries. Each PDU <NUM> further includes a plurality of output connectors for electrically connecting a plurality of corresponding electronic devices <NUM> via the switching devices <NUM>. The output connectors may be, for example and without limitations, C13-type plugs. In some embodiments, each PDU <NUM> includes eight (<NUM>) output connectors.

<FIG> shows a perspective view of the rack-mounted assembly <NUM>. As shown, the rack-mounted assembly <NUM> includes a detachable frame, or "board" <NUM> of the electronic device <NUM>, and an immersion case <NUM>. The board <NUM> holds electronic components <NUM> of the electronic device <NUM> and may be immersed in the immersion case <NUM>. Although the immersion case <NUM>, board <NUM>, and electronic components <NUM> are show as separate parts, it will be understood by one of ordinary skill in the art that, in some embodiments, two or more of these components could be combined. For example, the electronic components <NUM> could be fixed directly on the board <NUM> and/or the immersion case <NUM>.

It is contemplated that the electronic devices <NUM> may generate a significant amount of heat. Consequently, the rack system <NUM> may use a cooling system to cool down the electronic devices <NUM> to prevent the electronic devices <NUM> from being damaged. In this embodiment, the cooling system is a hybrid cooling system including an immersion cooling system and a channelized cooling system.

As used herein, an immersion cooling system is a cooling system in which the electronic device is in direct contact with a non-conductive (dielectric) cooling liquid, which either flows over at least portions of the electronic device, or in which at least portions of the electronic device are submerged. For example, in the rack-mounted assembly <NUM>, the immersion case <NUM> may contain a dielectric immersion cooling liquid (not shown in <FIG>). Further, the board <NUM> including the electronic components <NUM> may be submerged at least in part in the immersion cooling case <NUM>. In some embodiments, the dielectric immersion cooling liquid and the board <NUM> may be inserted into the immersion case <NUM> via an opening <NUM> at the top of the immersion case <NUM>. In some embodiments, the opening <NUM> may remain at least partially open during operation of the electronic device <NUM>, providing a non-sealed configuration for the immersion case <NUM>. Such non-sealed configurations may be easier to manufacture and maintain than sealed configurations, but may be inappropriate for, e.g., two-phase systems, in which the immersion cooling liquid may boil during operation of the electronic device <NUM>.

In some embodiments, the immersion case <NUM> may also include structures or devices for cooling the dielectric cooling liquid. For example, a convection-inducing structure, such as a serpentine convection coil <NUM> in which a flow of cooling liquid (e.g. water) is maintained may be used to cool the dielectric cooling liquid via natural convection. Alternatively or additionally, a pump (not shown) may be used to circulate the dielectric cooling liquid either within the immersion case <NUM> or through an external cooling system (not shown). In some embodiments, a two-phase system in which dielectric cooling liquid in a gaseous phase is cooled by condensation may be used. Generally, any technology or combination for cooling the dielectric cooling liquid may be used without departing from the principles disclosed herein. The serpentine convection coil <NUM> may be omitted or replaced with other convection-inducing structures or devices for circulating the dielectric immersion cooling liquid in some embodiments.

As used herein, a channelized cooling system is a cooling system in which heat-generating components of the electronic device <NUM> (i.e. the electronic components <NUM>) are cooled using one or more liquid cooling units <NUM>, which may also be called "cold plates" or "water blocks" (although a liquid circulating through the "water blocks" may be any of a wide variety of known thermal transfer liquids, rather than water). Liquid connections of the liquid cooling units <NUM> are described in greater details herein after. Examples of heat-generating components that may be cooled using such a thermal transfer devices include, but are not limited to, central processing units (CPUs), graphics processing units (GPUs), neural processing units (NPUs), tensor processing units (TPUs), power supply circuitry, and application specific integrated circuits (ASICs), including, for example, ASICs configured for high-speed cryptocurrency mining. The present disclosure describes a cooling monitoring system that detect anomalies of the cooling of the electronic device <NUM> and that may disconnect the electronic device <NUM> from its corresponding power supply in reponse to detecting an anomaly.

<FIG> is a schematic representation of a cooling monitoring system <NUM> implemented in the rack-mounted assembly <NUM> in accordance with some embodiments of the present technology. In the illustrative embodiment of <FIG>, the electronic device <NUM> is a server that may be implemented as a conventional computer server. In an example of an embodiment of the present technology, each electronic device <NUM> may be implemented as a Dell™ PowerEdge™ Server running the Microsoft™ Windows Server™ operating system. Needless to say, each electronic device <NUM> may be implemented in any other suitable hardware, software, and/or firmware, or a combination thereof.

The electronic device <NUM> includes one or more electronic components <NUM> (only one of which is illustrated for clarity of the <FIG>) and the board <NUM> on which the one or more electronic components <NUM> are mounted. The board <NUM> is at least in part immersed in the immersion case <NUM> that contains a volume of a heat-transfer liquid <NUM> for cooling of the electronic device <NUM>. More specifically, the electronic device <NUM> is at least in part immersed in the heat-transfer liquid <NUM> for immersion cooling thereof. In this embodiment, the heat-transfer liquid <NUM> is a dielectric cooling liquid. As such, the electronic device <NUM> may be referred to as a "immersion-cooled electronic device".

Additionally, the electronic device <NUM> is also cooled by the channelized cooling system that circulates a channelized cooling liquid, or a "second heat-transfer liquid", through one or more liquid cooling units <NUM> (only one of which is illustrated for clarity of the <FIG>) such as "water blocks" on the electronic component <NUM> or some other heat-generating components of the electronic device. The liquid cooling unit <NUM> has an external thermal transfer surface configured to be in contact with the electronic component <NUM>. It is to be understood that in this context, the external thermal transfer surface is said to be "in contact" with the electronic component <NUM> even in cases where a thermal paste is applied between the external thermal transfer surface and the electronic component <NUM>, in a manner that is known in the art, to ensure adequate heat transfer between the electronic component <NUM> and the external thermal transfer surface of the liquid cooling unit <NUM>. More specifically, in this embodiment, the liquid cooling unit <NUM> is thermally coupled to the electronic component <NUM> to be cooled, and the channelized cooling liquid is circulated through an internal liquid conduit (not shown) of the liquid cooling unit <NUM> to absorb the heat from the electronic device <NUM>. As the heat-transfer liquid flows out of the liquid cooling unit <NUM>, so does the thermal energy absorbed thereby.

The liquid cooling unit <NUM> may for example include a liquid inlet <NUM> fluidly connected to the liquid cooling inlet conduit <NUM> of the rack <NUM> (<FIG>) for receiving the second heat-transfer liquid. The second heat-transfer liquid may thus flow through the internal liquid conduit of the liquid cooling unit <NUM> that zigzags within the liquid cooling unit <NUM> to maximize the heat absorption potential of the heat-transfer liquid across a surface of the liquid cooling unit <NUM>. The internal liquid conduit may terminate at a liquid outlet <NUM> for discharging hot second heat-transfer liquid to the liquid cooling outlet conduit <NUM> of the rack <NUM> (<FIG>). The second heat-transfer liquid is further directed in a channelized cooling loop <NUM> to be cooled in a heat exchanger (e.g. a dry cooler).

In this embodiment, the liquid cooling unit <NUM> is also submerged within the heat-transfer liquid <NUM>. The serpentine convection coil <NUM> introduced in the description of <FIG>, if present, may be structured with multiple hollow-channel coils to provide a high surface area exposure relative to the heat-transfer liquid <NUM> while also maintaining compact overall length and width dimensions. With this structure, direct channelized liquid cooling within the serpentine convection coil <NUM> allows to cool the ambient temperature of the heat-transfer liquid <NUM> and to induce natural thermal convection in the heat-transfer liquid <NUM>. That is, the serpentine convection coil <NUM> internally conveys the circulating channelized cooling liquid that operates to cool the heat-transfer liquid <NUM>. The channelized cooling liquid may be a different liquid than the heat-transfer liquid <NUM>. That is, the channelized cooling liquid may include water, alcohol, or any suitable liquid capable of sustaining adequate cooling temperatures. In some embodiments, the channelized cooling liquid comprisees water and glycol. As illustrated, the serpentine convection coil <NUM> is connected in series with the liquid cooling unit <NUM>, the latter being in a downstream position. In one alternative, the liquid cooling unit <NUM> may be upstream of the serpentine convection coil <NUM>. In another alternative, the channelized cooling liquid may flow in parallel within the liquid cooling unit <NUM> and the serpentine convection coil <NUM>. In yet another alternative, the liquid cooling unit <NUM> and the serpentine convection coil <NUM> may be independent, being connected to different sources of cooling liquid. It will be understood that although the system shown in <FIG> uses the serpentine convection coil <NUM> for cooling the heat-transfer liquid <NUM>, other convection-inducing structures (not shown) or other cooling technologies (not shown), as discussed above, could be used instead of or in addition to the serpentine convection coil <NUM>.

After absorbing heat from the electronic device <NUM> and from the heat-transfer liquid <NUM>, the heated channelized cooling liquid is conveyed through a heat exchanger system (not shown), the operation of which will generally be familiar to those of skill in the art. The heat exchanger system cools the channelized cooling fluid, which may then be recirculated to the rack system <NUM> through a channelized cooling loop.

It will be understood that there may be many additional features, combinations, and variations of such hybrid cooling systems combining channelized liquid cooling and immersion cooling of the electronic device <NUM>. In some embodiments, multiple electronic devices, similar to the electronic device <NUM>, may be immersed in a single immersion case or an immersion tank.

Other variations may involve changing the order of the components and/or the serpentine convection coil in the channelized cooling loop. For example, the channelized cooling fluid may flow through the serpentine convection coil after flowing through the liquid cooling unit <NUM>. In some embodiments, the serpentine convection coil may be part of a different channelized cooling loop than the liquid cooling units <NUM>. These variations and additional features may be used in various combinations, and may be used in connection with the embodiments described above, or other embodiments.

The cooling monitoring system <NUM> includes the controller <NUM> and one or more sensors communicably connected to the controller <NUM>. In an embodiment, the sensors transmit measurement signals for the operating parameter of the heat-transfer liquid <NUM> to the controller <NUM>. The controller <NUM> further determines that the measurement signals indicate that the operating parameter of the heat-transfer liquid <NUM> is above the threshold by comparing measurement values carried in the measurement signals with the threshold.

In another embodiment, the sensors transmit a fault signal to the controller <NUM> in response to detecting that the operating parameter of the heat-transfer liquid <NUM> is above the threshold. The controller <NUM> further cause to disconnect the electronic device <NUM> from the power supply in response to receiving the fault signal. In this embodiment, the sensors may thus be refered to as "anomaly sensors".

Operating parameters that are measured by the sensors may be a temperature, a conductivity, a viscosity, a density, and/or any other physical or chemical characteristics of the heat-transfer liquid <NUM>.

As shown in <FIG>, the controller <NUM> is mounted on the board <NUM> of the electronic device <NUM> and operably connected to the corresponding switching device <NUM> of the electronic device <NUM> such that, in use, the controller <NUM> may open or close the switching device <NUM>. More specifically, the controller <NUM> causes to disconnect, in response to determining that the measurement signals received from the sensors indicate that the operating parameter of the heat-transfer liquid <NUM> is above a given threshold, the electronic device <NUM> (i.e. the electronic components <NUM>) from the power supply. As such, the cooling monitoring system <NUM> may increase safety of the rack system <NUM> and, more generally, of the datacenter, by electrically and individually disconnecting servers or other electronic devices <NUM> from power supplies in response to detecting faulty cooling in corresponding rack-mounted assemblies <NUM>.

In an embodiment, the switching device <NUM> may be integrated in the electronic device <NUM>. In other embodiments, the switching device <NUM> may be located outside the electronic device <NUM> (e.g. along a power line that transmits electric power from the PDU <NUM> to the electronic device <NUM>).

As has been discussed above, hybrid cooling systems for electronic devices120 may include both immersion cooling systems, in which the electronic devices are immersed or submerged in a dielectric immersion cooling liquid, and channelized cooling systems, in which heat transfer devices such as water blocks are used to cool components of the electronic device, using a liquid that flows through channels between and within the heat transfer devices.

In some cases, the same liquid may be used as both the dielectric immersion cooling liquid and the channelized cooling liquid (i.e., the liquid that flows through the water blocks). However, in some systems, the characteristics of the dielectric immersion cooling liquid and/or the cost of the dielectric immersion cooling liquid may render it inappropriate for use in the channelized cooling system. Often, the channelized cooling liquid will be water, or some other liquid that provides appropriate heat transfer characteristics for the channelized cooling system, but may not be usable for immersion cooling, e.g., due to its conductivity or due to corrosion or other damage that it may cause to components of the electronic device. For example, if water is used as the channelized cooling liquid, it is likely that the concentration of ions in the water will cause the water to be sufficiently conductive to cause damage to electronic components. Even if the water is initially provided as distilled or deionized water, the concentration of ions will increase as the water is circulated through the channelized cooling system.

To avoid damage to immersed or submerged electronic devices, it is desirable to determine whether channelized cooling liquid is leaking into the dielectric immersion cooling liquid. Dielectric immersion cooling liquids are typically either hydrocarbon- or fluorocarbon-based and typically have densities that are lower than the density of water. If the channelized cooling liquid has a higher density than the dielectric immersion cooling liquid, which will typically be the case, then the channelized cooling fluid eventually leaking into the immersion cooling liquid will sink to a bottom portion of the immersion case.

In accordance with various embodiments of the disclosure, a leak detection arrangement, such as a sensor, may be installed in a bottom portion of the immersion case <NUM> of each rack-mounted assembly <NUM> (or in a bottom portion of any part of the rack system <NUM> where the dielectric cooling liquid may flow) to detect the presence of the channelized cooling liquid, which would indicate that there is a leak in the channelized cooling system. Generally, this bottom portion of the immersion case <NUM> should be far enough below any immersed or submerged electronic device <NUM> that, absent a major leak, the channelized cooling fluid will not collect around any components of the electronic device <NUM>. Once the fluid is detected, an alarm may be raised, or an operator may otherwise be informed of the immersion case <NUM> in which the leak was detected so that remedial measures may be taken.

In an embodiment, the sensors include a leak detection arrangement <NUM> communicably connected to the controller <NUM> and adapted to determine a presence of the second heat-transfer liquid in a bottom portion of the immersion case <NUM>. More specifically, the second heat-transfer liquid used for liquid cooling of the electronic device <NUM> is selected to have a density that is higher than a density of the heat-transfer liquid <NUM>. As a result, in case of leakage of the second heat-transfer liquid within the immersion case <NUM>, the second heat-transfer liquid sinks to the bottom of the immersion case <NUM>. In this embodiment, in order to detect a presence of the second heat-transfer liquid in the immersion case <NUM>, the leak detection arrangement <NUM> is disposed in a bottom portion of the board <NUM>. Broadly speaking, the leak detection arrangement <NUM> may include any sensor adapted to measure a temperature, a conductivity, a viscosity, a density, and/or any other physical or chemical characteristics of the heat-transfer liquid <NUM>.

In an embodiment, the leak detection arrangement <NUM> includes one or more conductivity sensors <NUM> for determining a conductivity of a fluid at the bottom portion of the board <NUM>. In this embodiment, the second heat-transfer liquid is water. As a result, the conductivity sensors <NUM> are expected to determine a conductivity value that is non-null, or at least a variation of the measured conductivity value, in response to some of the second heat-transfer liquid having leaked to the bottom portion of the immersion case <NUM>.

In an embodiment, the leak detection arrangement <NUM> transmits measurement signals including information about a measured conductivity of the heat-transfer liquid <NUM> to the controller <NUM>. The controller <NUM> further determines that the measurement signals indicate that the conductivity of the heat-transfer liquid <NUM> is above the threshold by comparing measurement values carried in the measurement signals with the pre-determined conductivity threshold.

In another embodiment, the leak detection arrangement <NUM> transmits a fault signal to the controller <NUM> in response to determining that a real measured conductivity is above a predetermined conductivity threshold. In some embodiments, value of the pre-determined conductivity threshold is stored in a memory of the controller <NUM> and the leak detection arrangement <NUM> transmits data including information about the real measured conductivity. The controller <NUM> then compares the real measured conductivity to the pre-determined conductivity threshold. In response to the real measured conductivity being greater than the pre-determined conductivity threshold, the controller <NUM> may open the switching device <NUM>.

In this embodiment, the leak detection arrangement <NUM> includes a plurality of conductivity sensors <NUM> disposed one above another along a gravity axis, each conductivity sensor <NUM> being communicably connected to the controller <NUM>. In use, a fill rate of the second heat-transfer liquid in the immersive case <NUM> may be determined based on conductivity values measured by the conductivity sensors <NUM>. More specifically, as the second heat-transfer liquid leaks from the channelized cooling loop <NUM>, a bottommost conductivity sensor <NUM> may first transmit a fault signal to the controller <NUM>. Later in time as the second heat-transfer liquid continues to leak from the channelized cooling loop <NUM> and fills the immersion case <NUM>, a second conductivity sensor <NUM>, adjacent and above the bottommost conductivity sensor <NUM> along the gravity axis, may further transmit a second fault signal to the controller <NUM> upon measuring a conductivity value above the pre-determined conductivity threshold. Altenatively, the.

A fill rate and temporal evolution thereof may thus be determined based on times of reception of the different fault signals from the respective conductivity sensors <NUM>. In some embodiments, the controller <NUM> further triggers, in response to determining the fill rate, a counter <NUM> indicative of an amount of time that has passed since the fill rate has been determined. In response to the counter <NUM> reaching a first pre-determined count value, the controller <NUM> may cause to disconnect the electronic device <NUM> from the power supply. More specifically, once the counter <NUM> reaches the first pre-determined count value, the controller <NUM> may open the switching device <NUM> to disconnect from the PDU <NUM> and from the power supply. In some embodiments, in response to the counter <NUM> reaching a second pre-determined count value, the controller <NUM> may transmit an alert signal to an operator device communicably connected thereto to indicate occurence of an anomaly to an operator of the datacenter. The second pre-determined count value may be smaller than the first pre-determined count value. There may be a higher number of pre-determined count values and associated alert signals in alternative embodiments.

In some embodiments, the pre-determined count value is based on the determined fill rate. For example, the pre-determined count value associated with fill rate determined to be between <NUM> per hour and <NUM> per hour may be <NUM> minutes. The pre-determined count value associated with fill rate determined to be between <NUM> per hour and <NUM> per hour may be <NUM> minutes. The controller <NUM> may thus disconnect the electronic device <NUM> from the power supply before the leaking channelized cooling liquid reaches sensitive components of the electronic device <NUM> (e.g. the electronic components <NUM>).

In an embodiment, the cooling monitoring system <NUM> further includes a temperature sensor <NUM>. The temperature sensor <NUM> measures a temperature of the heat-transfer liquid <NUM>, a vapor thereof and/or air located at a top portion of the immersion case <NUM>. The temperature sensor <NUM> may be located near a top of the heat-transfer liquid <NUM>, as shown on <FIG>, or may be placed in any other suitable location. The temperature sensor <NUM> transmits a fault signal to the controller <NUM> in response to measuring a temperature above a pre-determined temperature threshold. As such, the controller <NUM> may open the switching device <NUM> to disconnect from the PDU <NUM> and from the power supply in response to the temperature at the top portion of the immersion case being greater than the pre-determined temperature threshold.

In some embodiment, the controller <NUM> may trigger a new parallel instance of the counter <NUM> upon receiving the fault signal from the temperature sensor <NUM>. In response to the counter reaching a third pre-determined count value, the controller <NUM> may cause to disconnect the electronic device <NUM> from the power supply. More specifically, once the counter <NUM> reaches the third pre-determined count value, the controller <NUM> may open the switching device <NUM> to disconnect the electronic device <NUM> from the PDU <NUM> and from the power supply. In some embodiments, in response to the counter <NUM> reaching a fourth pre-determined count value, the controller <NUM> may transmit an alert signal to an operator device communicably connected thereto to indicate occurence of an anomaly to an operator of the datacenter. The fourth pre-determined count value may be smaller than the first pre-determined count value.

In a given rack system (e.g. the rack system <NUM>), selective disconnection of the electronic devices <NUM> from the power supply by the corresponding controllers <NUM> facilitates operation of the electronic devices <NUM> in case an anomaly is detected. Indeed, if a faulty cooling system is detected by a corresponding cooling monitoring system <NUM>, the corresponding electronic device <NUM> is disconnected from the power supply without impacting operation of the other electronic devices <NUM> in other rack-mounted assemblies <NUM> of the rack system <NUM>. For example, propagation of potential damages of a short-circuit occurring in a given electronic device <NUM> (e.g. server) of the datacenter is limited by individual discsonnection of the servers from the power supply.

In some embodiments, the controller <NUM> is communicably connected with an operator interface (not shown) of the datacenter (e.g. a control room of the datacenter) and transmits, in response to determining occurence of an anomaly, a second fault signal to the operator including information about the faulty electronic device <NUM> in which the cooling monitoring system <NUM> has detected an anomaly (e.g. leaking channelized cooling liquid). Said information may include, without limitation, an identification of the faulty electronic device <NUM> and data provided by the sensors.

In some embodiments, the controller <NUM> is communicably connected with a valve (e.g. a solenoid valve) located in the channelized cooling loop <NUM> upstream the serpentine convection coil <NUM> and the liquid cooling unit <NUM>, external to the immersion case <NUM>. In response to determining occurence of an anomaly, the controller <NUM> also closes the valve in order to limit damages to the electronic device <NUM>.

<FIG> shows an embodiment, in which the varying electrical properties of the liquids are used to detect a leak of the channelized cooling liquid. A bottom portion <NUM> of the immersion case <NUM> of a hybrid cooling system that includes both the aforementioned immersion cooling and channelized liquid cooling is shown. In this embodiment, each conductivity sensor <NUM> of the leak detection arrangement <NUM> includes electrodes <NUM> and <NUM>, which are used to measure the conductivity of the liquid between the electrodes <NUM> and <NUM>. This may be done, e.g., by imposing a constant voltage between the electrodes <NUM> and <NUM>, and measuring changes in the current that occur as a result of the conductivity/resistivity of the liquid. It will be understood that other known methods for measuring conductivity/resistivity could also be used.

The dielectric immersion cooling liquid <NUM> has very low conductivity. Thus, when there has been no leak, there will be low conductivity (or high resistivity) between the electrodes <NUM> and <NUM>. In the example shown in <FIG>, a leak has occurred in the channelized cooling system, so channelized cooling liquid <NUM> is collected at the bottom of the immersion case <NUM>. The conductivity of the channelized cooling liquid <NUM> is much higher than the conductivity of the dielectric immersion cooling liquid <NUM>. When the level of the channelized cooling liquid <NUM> reaches the bottommost conductivity sensor <NUM>, this difference in conductivity is detected by the electrodes <NUM> and <NUM>, indicating that a leak has occurred.

It will be understood by those of ordinary skill in the art that many variations on a system that uses conductivity or resistivity measurement to detect the presence of the channelized cooling liquid may be used. For example, the electrodes <NUM> and <NUM> may be disposed within a single unit or holder of a given conductivity sensor <NUM> that is open to liquid, and that holds the electrodes <NUM> and <NUM> at a predetermined distance from each other. In some embodiments, such a holder may be configured to be mounted in the immersion case <NUM> through a "standardized" opening in the bottom portion of the immersion case <NUM>, which is configured to receive any of a variety of sensors or other leak detection arrangements for determining the presence of the channelized cooling liquid in the bottom portion of the immersion case <NUM>.

In the illustrative embodiment of <FIG>, the bottommost conductivity sensor <NUM> is immersed in the leaked channelized cooling liquid <NUM>. A first conductivity measurement signal, which may in this case be a fault signal, may thus be transmitted by the bottommost conductivity sensor <NUM> to the controller <NUM>. In response to the level of the leaked channelized cooling liquid <NUM> reaching a consecutive conductivity sensor <NUM>, a second conductivity measurement signal, which may in this case be another fault signal, may be transmitted by said consecutive conductivity sensor <NUM> to the controller <NUM>. A difference between reception times of the first and second signals may be used by the controller <NUM> to further determined the fill rate of the leaked channelized cooling liquid <NUM>.

<FIG> shows an embodiment in which a difference in pH is used to detect a leak. In this embodiment, the leak detection arrangement <NUM> includes one or more pH sensors <NUM>, which are used to measure the pH of the liquid in the immediate vicinity of the pH sensors <NUM>. It will be understood that any known electrical, electrochemical, or electronic method for measuring pH could be used by the pH sensors <NUM>.

The dielectric immersion cooling liquid <NUM> and the channelized cooling liquid may have different pH values. The liquids may be selected to have this characteristic, or the pH may be measurably different simply due to chemical differences between the two liquids. In the example shown in <FIG>, a leak has occurred in the channelized cooling system, so the channelized cooling liquid <NUM> has collected at the bottom of the immersion case <NUM>. The bottommost pH sensor <NUM> will detect that the liquid in the immediate vicinity of the pH sensor has a different pH than the dielectric immersion cooling liquid <NUM>, indicating that a leak has occurred.

As with other embodiments, it will be understood by those of ordinary skill in the art that many variations on a system that uses pH measurements to detect the presence of the channelized cooling liquid may be used. For example, the pH sensor may be configured to be mounted in the immersion case through a "standardized" opening in the bottom portion of the immersion case, which is configured to receive any of a variety of sensors or other leak detection arrangements for determining the presence of the channelized cooling liquid in the bottom portion of the immersion case.

As an example, <FIG> is a schematic block diagram of the controller <NUM> of the cooling monitoring system <NUM> according to an embodiment of the present technology. The controller <NUM> comprises a processor or a plurality of cooperating processors (represented as a processor <NUM> for simplicity), a memory device or a plurality of memory devices (represented as a memory device <NUM> for simplicity), and an input/output interface <NUM> (or separate input and output interfaces) allowing the controller <NUM> to communicate with other components of the cooling monitoring system <NUM> and/or other components in remote communication with the cooling monitoring system <NUM>. The processor <NUM> is operatively connected to the memory device <NUM> and to the input/output interface <NUM>. The memory device <NUM> includes a storage for storing parameters <NUM>, including for example and without limitation the above-mentioned predetermined conductivity thresholds. The memory device <NUM> may comprise a non-transitory computer-readable medium for storing code instructions <NUM> that are executable by the processor <NUM> to allow the controller <NUM> to perform the various tasks allocated to the controller <NUM>.

The controller <NUM> is operatively connected, via the input/output interface <NUM>, to the leak detection arrangement <NUM>, the switching device <NUM> and the temperature sensor <NUM>. The controller <NUM> executes the code instructions <NUM> stored in the memory device <NUM> to implement the various above-described functions that may be present in a particular embodiment. <FIG> as illustrated represents a non-limiting embodiment in which the controller <NUM> orchestrates operations of the cooling monitoring system <NUM>. This particular embodiment is not meant to limit the present disclosure and is provided for illustration purposes.

Even though the controller <NUM> is depicted as a separate entity on <FIG>, the controller <NUM> may be part of electroinc device <NUM> and, more specifically, of the electronic components <NUM>. The functions of the controller <NUM> described in the present disclosure may be performed by the electronic components <NUM> or any electronic component of the electronic device <NUM>. In alternative embodiments, the controller <NUM> is remotely connected (e.g. via a networking interface) to the switching device <NUM>, the temperature sensor <NUM>, the leak detection arrangement <NUM> and/or the electronic device <NUM>.

It is to be understood that the operations and functionality of the described cooling monitoring system <NUM>, its constituent components, and associated processes may be achieved by any one or more of hardware-based, software-based, and firmware-based elements. Such operational alternatives do not, in any way, limit the scope of the present disclosure.

In some embodiments, the cooling monitoring system <NUM> are part of the electronic device <NUM>. More specifically, the electronic device <NUM> may include the sensors (i.e. the leak detection arrangement <NUM> and the temperature sensor <NUM>) mounted on the board <NUM> of the electronic device <NUM> and communicably connected to the electronic device <NUM>, the functions of the controller <NUM> being performed by the electronic device <NUM>.

It will be understood that, although the embodiments presented herein have been described with reference to specific features and structures, various modifications and combinations may be made without departing from the scope defined by the appended claims. For example, it is contemplated that in some embodiments, two or more of the leak detection arrangements described above may be used, in any combination. For instance, an embodiment may use a combination of a pH sensor and a conductivity sensor to detect leaks, and may also include a valve to permit manual testing and draining of leaked channelized cooling liquid. The specification and drawings are, accordingly, to be regarded simply as an illustration of the discussed implementations or embodiments and their principles as defined by the appended claims, and are contemplated to cover any and all modifications, variations, combinations or equivalents that fall within the scope defined by the appended claims.

Claim 1:
An electronic device (<NUM>) receiving electric power from a power supply, the electronic device (<NUM>) comprising:
a board (<NUM>) at least in part immersed in an immersion case (<NUM>) comprising a first heat-transfer liquid (<NUM>) for cooling of the electronic device (<NUM>);
the electronic device (<NUM>) being characterized in one or more electronic components (<NUM>) mounted onto the board (<NUM>) and cooled by one or more corresponding liquid cooling units (<NUM>) in thermal contact therewith, a second heat-transfer fluid being channelized in the one or more liquid cooling units (<NUM>) to collect thermal energy generated by the one or more electronic components (<NUM>);
the electronic device (<NUM>) further comprises
a leak detection arrangement (<NUM>) disposed in a bottom portion of the board (<NUM>) and configured to determine a presence of the second heat-transfer liquid in a bottom portion of the immersion case (<NUM>), the second heat-transfer liquid having a density that is higher than a density of the first heat-transfer liquid (<NUM>); and
a controller (<NUM>) communicably connected to the leak detection arrangement (<NUM>), the controller (<NUM>) being configured to receive signals from the leak detection arrangement (<NUM>) and, in response to determining that the signals indicate presence of the second heat-transfer liquid in the bottom portion of the immersion case (<NUM>), cause to disconnect the electronic device (<NUM>) from the power supply.