Spray cooling for emergency protection of immersion-cooled devices during coolant loss events

Abstract

Computing components in data centers generate heat as they operate. If they are not cooled properly, they can overheat. To prevent overheating, computing components can be cooled through two-phase immersion cooling in thermally conductive, dielectric liquid coolant. Heat from the computing components vaporizes the liquid coolant, which rises to and is cooled by a condenser coil above the computing components, dissipating the heat. If the coolant leaks, though, then the immersion cooling system may not cool the computing components effectively enough to prevent them from overheating. To guard against overheating caused by coolant leaks, sensors monitor the coolant level and temperature of the coolant and / or computing components. If the coolant level falls and the temperature rises, then some of the remaining liquid coolant is pumped through a spray nozzle and onto the exposed computing components, preventing the computing components from overheating.

Description

SPRAY COOLING FOR EMERGENCY PROTECTION OF IMMERSION- COOLED DEVICES DURING COOLANT LOSS EVENTSCROSS-REFERENCE TO RELATED APPLICATION

[0001] This Application claims the benefit of provisional U.S. Application No. 63 / 677,813, filed on July 31, 2024, and entitled “SPRAY COOLING FOR EMERGENCY PROTECTION OF IMMERSION-COOLED DEVICES DURING COOLANT LOSS EVENTS,” which is hereby incorporated by reference in its entirety.

[0002] In cases where the present application conflicts with a document incorporated by reference, the present application controls.BACKGROUND

[0003] One challenge with operating a data center is keeping the computing components cool enough to operate quickly and efficiently. Dissipating the heat generated by the computing components becomes more challenging as the number of components grows and the operating temperatures of the computing components increase. Unfortunately, air cooling is usually not sufficient to cool the large number of computing components in a modem data center.

[0004] Fortunately, it is feasible to cool computing components by immersing or submerging them in a thermally conductive dielectric liquid coolant. This type of cooling, called immersion cooling, offers several advantages over air cooling. First, it works without cooling fins or fans on the servers or other computing components being cooled, reducing the size, weight, and power consumption of the computing components being cooled. Second, it works without a refrigerated air conditioning system, further reducing data center power consumption. Third, the liquid coolant has a higher heat capacity than air, so a given volume of liquid coolant can dissipate more heat than the same volume of air.

[0005] There are two types of immersion cooling: single-phase immersion cooling and two-phase immersion cooling. In single-phase immersion cooling, the computing components are submerged in liquid coolant that circulates between a vessel containing the computing components and a heat exchanger. As it circulates, the liquid coolant moves heat generated by the computing components to a cold-water circuit or other heat sink thermally coupled to the heat exchanger. The coolant remains in the liquid phase as it circulates, hence the name “single -phase” immersion cooling.

[0006] In two-phase immersion cooling, the computing components are submerged in liquid coolant with a relatively low boiling point (e.g., at or about 50 °C). The liquid coolant absorbs heat generated by the computing components; this causes the liquid coolant to evaporate. The coolant vapor rises from the surface of the liquid coolant, moving heat away from the computing component. The coolant vaper is cooled by a heat exchanger, such as a condenser coil, and returns to the liquid phase in the vessel holding the computing components and the liquid coolant.SUMMARY

[0007] Embodiments of the present technology include a system with an immersion tank, sensor, temperature sensor, spray nozzle, pump, and controller. In operation, the immersion tank holds a computing component in a liquid coolant, such as a thermally conductive dielectric liquid coolant. The sensor senses a level of the liquid coolant in the immersion tank and the temperature sensor senses a temperature of the computing component and / or of the liquid coolant. The spray nozzle is disposed in the immersion tank and sprays the liquid coolant on the computing component in case of a liquid coolant loss. The pump, which is in fluid communication with the liquid coolant and spray nozzle, pumps the liquid coolant through the spray nozzle. And the controller, which is operably coupled to the pump, sensor, and temperature sensor, actuates the spray nozzle in response to an indication from the sensor that the level of the liquid coolant in the immersion tank is below a predetermined level (e.g., at or a below an upper surface or edge of the computing component) and / or an indication from the temperature sensor that the temperature of the computing component and / or of the liquid coolant is above a predetermined temperature.

[0008] The spray nozzle can be configured to spray the liquid coolant on a surface of the computing component exposed by a drop in the level of the liquid coolant. The spray nozzle may be a first spray nozzle in a plurality of spray nozzles configured to spray the liquid coolant on a surface of the computing component, in which case the controller may be configured to determine a temperature gradient within the immersion tank and to actuate the plurality of spray nozzles based on the temperature gradient.

[0009] The controller can be configured to adjust the pump rate of the pump to prevent or reduce cavitation of the liquid coolant in the pump. The controller can also be configured to trigger transfer of data from the computing component to another computing component outside the immersion tank in response to the indication from the sensor that the level of the liquid coolant in the immersion tank is below a predetermined level and / or the indication from the temperaturesensor that the temperature of the computing component and / or of the liquid coolant is above a predetermined temperature. The controller can be further configured to trigger re-assignment of at least one pending task from the computing component to another computing component outside the immersion tank in response to the indication from the sensor that the level of the liquid coolant in the immersion tank is below a predetermined level and / or the indication from the temperature sensor that the temperature of the computing component and / or of the liquid coolant is above a predetermined temperature. And the controller can be configured to trigger re-direction of at least one incoming task from the computing component to another computing component outside the immersion tank in response to the indication from the sensor that the level of the liquid coolant in the immersion tank is below a predetermined level and / or the indication from the temperature sensor that the temperature of the computing component and / or of the liquid coolant is above a predetermined temperature. The controller can issue an alert in response to the indication from the sensor that the level of the liquid coolant in the immersion tank is below a predetermined level and / or the indication from the temperature sensor that the temperature of the computing component and / or of the liquid coolant is above a predetermined temperature.

[0010] The system can also include a condenser coil, disposed in the immersion tank above the computing component, to condense liquid coolant vaporized by heat emitted by the computing component. The system may also include an auxiliary tank, in fluid communication with the immersion tank via the spray nozzle, to supply additional liquid coolant.

[0011] Some examples of the system include a coolant filtration system, in fluid communication with the immersion tank via the spray nozzle, to filter the liquid coolant. The coolant filtration system can include an outlet, in fluid communication with the immersion tank, to dispense filtered liquid coolant into the immersion tank and a valve, in fluid communication with the outlet and the spray nozzle and operably coupled to the controller, to direct the filtered liquid coolant to the immersion tank via the outlet or the spray nozzle in response to actuation by the controller.

[0012] The system can also include an inducer, in fluid communication with the pump, to raise the pressure of the liquid coolant entering the pump. And the system can include a pressure relief valve, in fluid communication with the immersion tank, to relieve pressure within the immersion tank.

[0013] Embodiments also include methods of cooling a computing component immersed in liquid coolant in an immersion tank. These methods may include: sensing a level of the liquid coolant in the immersion tank; sensing a temperature of the computing component and / or of the liquidcoolant; determining that the level of liquid coolant in the immersion tank is below a predetermined level and / or the temperature of the computing component and / or of the liquid coolant is above a predetermined temperature; and in response to determining that the level of liquid coolant in the immersion tank is below the predetermined level and / or that the temperature of the computing component and / or of the liquid coolant is above the predetermined temperature, spraying the liquid coolant on the computing component to cool the computing component.

[0014] Sensing the temperature of the computing component and / or of the liquid coolant can include sensing the temperature at each of plurality of locations within the immersion tank.

[0015] Spraying the liquid coolant can include pumping the liquid coolant in the immersion tank through a spray nozzle onto an exposed surface of the computing component. It can also include pumping the liquid coolant from an auxiliary tank through a spray nozzle onto an exposed surface of the computing component. Spraying the liquid coolant can also include actuating a valve to direct the liquid coolant from a filter through a spray nozzle. And spraying the liquid coolant can include directing the liquid coolant through each of a plurality of spray nozzles in the immersion tank, e.g., with spray nozzles actuated independently. Spraying the liquid coolant allows the computing component to complete a computing task being performed by the computing component without experiencing thermal damage.

[0016] Example methods may include one or more of multiple different responses to determining that the level of liquid coolant in the immersion tank is below the predetermined level and / or that the temperature of the computing component and / or of the liquid coolant is above the predetermined temperature. These responses include: transferring data from the computing component to another computing component outside the immersion tank; re-assigning at least one pending task from the computing component to another computing component outside the immersion tank; re-directing incoming tasks from the computing component to another computing component outside the immersion tank; and issuing an alert in response to determining that the level of liquid coolant in the immersion tank is below the predetermined level and / or that the temperature of the computing component and / or of the liquid coolant is above the predetermined temperature.

[0017] Another example system includes an immersion tank, a condenser coil, a sensor, temperature sensors, spray nozzles, a pump, and a controller. The immersion tank holds computing components in a liquid coolant. Heat generated by the computing components causes the liquid coolant to boil and / or evaporate. The condenser coil, which is disposed in the immersion tankabove the computing components and the liquid coolant, condenses evaporated coolant. The sensor senses the level of the liquid coolant in the immersion tank. The temperature sensors to sense temperatures of the computing components and / or of the liquid coolant. The spray nozzles, which are disposed in the immersion tank, spray the liquid coolant on the computing components in case of a liquid coolant loss. The pump, which is in fluid communication with the liquid coolant and spray nozzles, pumps the liquid coolant through the spray nozzles. And the controller, which is operably coupled to the pump, the sensor, and the temperature sensors, actuates the spray nozzles and issues an alert in response to an indication from the sensor that the level of the liquid coolant in the immersion tank is below a predetermined level and / or an indication from the temperature sensors that at least one of the temperatures of the computing components and / or of the liquid coolant is above a predetermined temperature.

[0018] All combinations of the foregoing concepts and additional concepts discussed in greater detail below (provided such concepts are not mutually inconsistent) are part of the inventive subject matter disclosed herein. In particular, all combinations of subject matter appearing in this disclosure are part of the inventive subject matter disclosed herein. The terminology used herein that also may appear in any disclosure incorporated by reference should be accorded a meaning most consistent with the particular concepts disclosed herein.BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The skilled artisan will understand that the drawings primarily are for illustrative purposes and are not intended to limit the scope of the inventive subject matter described herein. The drawings are not necessarily to scale; in some instances, various aspects of the inventive subject matter disclosed herein may be shown exaggerated or enlarged in the drawings to facilitate an understanding of different features. In the drawings, like reference characters generally refer to like features (e.g., functionally and / or structurally similar elements).

[0020] FIG. 1A shows a two-phase immersion cooling system with a spray cooling system that detects coolant loss and protects the immersion-cooled computing components in the event of coolant loss.

[0021] FIG. IB shows the two-phase immersion cooling system and spray cooling system of FIG. 1A during a coolant loss event.

[0022] FIG. 2 shows a two-phase immersion cooling system with a combination spray cooling and coolant filtration system.

[0023] FIG. 3 shows a two-phase immersion cooling system with a spray cooling system that draws liquid coolant from an auxiliary coolant reservoir.

[0024] FIG. 4 shows a two-phase immersion cooling system with a spray cooling system that includes a network of independently actuated nozzles.

[0025] FIG. 5A shows a single-phase immersion cooling system with a spray cooling system that detects coolant loss and protects the immersion-cooled computing components in the event of coolant loss.

[0026] FIG. 5B shows the single-phase immersion cooling system and spray cooling system of FIG. 5A during a coolant loss event.DETAILED DESCRIPTION

[0027] One challenge with immersion cooling is that the coolant can leak out of the immersion tank that holds the coolant and the computing components. For instance, a crack in a pass-though, a cut in a gasket, or an insufficiently sealed lid can allow the coolant to escape from the immersion tank, either in liquid or vapor form. Even slow vapor loss from the immersion tank can lead to appreciable coolant loss over time.

[0028] Coolant loss poses a dire risk to server thermal management. If the coolant level falls too low, then the coolant may not keep the computing components cool enough to avoid shutdown, thermal damage, or permanent thermal failure. Although these failure modes tend to be rare, their consequences can be catastrophic. Unfortunately, passive cooling within the immersion tank does not offer protection in these rare failure modes.Two- Phase Immersion Cooling with Emergency Spray Cooling

[0029] FIGS. 1A and IB show a two-phase immersion cooling system 100 with a spray cooling system 120 for cooling exposed computing components in the event of coolant loss due to a leak or other emergencies. The immersion cooling system 100 includes a sealed immersion tank 102 that holds one or more computing components 104, such as servers, graphics processing units (GPUs), memory, power supplies, or switches, which are operably connected to other computing components or systems outside the immersion tank 102, e.g., via the internet or another computer network. The computing components 104 are immersed in thermally conductive dielectric liquid coolant 110, or coolant 110, such as a fluorochemical with high density, low viscosity, low vapor pressure, and low surface tension.

[0030] Because the immersion cooling system 100 is a two-phase immersion cooling system, it also includes a condenser coil 112 filled with chilled water or another suitable chilled fluid. Pipes or conduits 114 and a pump 116 connect the condenser coil 112 to a heat rejection sub-system 118, such as a heat exchanger, chilled water loop, evaporative cooling tower, dry cooler, or other suitable mechanism for dissipating heat.

[0031] The spray cooling system 120 includes a board management controller (BMC) 122 that is operably coupled to a temperature sensor 123, a liquid level sensor 124, a pump 126 (e.g., a brushless pump), and possibly to the computing components 104 and to computing components or systems outside immersion tank 102. The pump 126 has an inlet at or near the bottom of the immersion tank 102 below the (normal) level 111 of the coolant surface. A pipe or fluid conduit 127 connects the outlet of the pump 126 to a spray nozzle 128, which is mounted above the (normal) level 111 of the coolant surface and pointed toward or at the computing components 104. The type, size, and shape of spray nozzle 128 can be selected based on the relatively high density and relatively low viscosity of the liquid coolant 110.

[0032] One challenge with pumping the liquid coolant 110 through the spray nozzle 128 is preventing or reducing cavitation in the pump 126. Cavitation occurs when vapor bubbles form in the liquid coolant 110 flowing through the pump 126 because the pressure of the liquid coolant 110 has fallen below the liquid coolant’s vapor pressure. In other words, cavitation occurs when the liquid coolant 110 evaporates as it moves through the pump 126. Cavitation can erode the pump’s impeller blades and reduce the pump’s efficiency by distorting the flow pattern of the liquid coolant 110 through the pump 126. It is also noisy. Warmer liquid is generally more likely to cavitate when flowing through the pump 126 than cooler liquid. As shown in FIGS. 1A and IB, mounting the pump 126 near the condenser coils 112, which are usually the coolest portion of the immersion tank 102, keeps the pump 126 cooler and reduces the likelihood of cavitation. Other ways to reduce or prevent cavitation include reducing the flow rate of liquid coolant 110 through the pump 126, e.g., in response to a command from the BMC 122, or placing an inducer the fluid path before the pump 126.

[0033] The temperature sensor 123 is in thermal communication with the computing components 104 and the coolant 110 and may be mounted on the immersion tank 102, one of the computing components 104, or another component or structure within the immersion tank 102. The spray cooling system 120 can include a single temperature sensor 123 or a set or network of temperaturesensors 123, for example, one temperature sensor 123 on / for each computing component 104 or even of the immersion tank 102.

[0034] The liquid level sensor 120 can be a capacitive liquid level sensor, optical (e.g., reflective) liquid level sensor, ultrasonic liquid level sensor, radar liquid level sensor, pressure sensor or transducer, or any other sensor suitable for measuring the level of the coolant surface relative to the level 111 of the upper surface(s) of the computing components 104 or another suitable reference level. The liquid level sensor 120 can be mounted on the inner side of the immersion tank 102, e.g., pointing sideways along at the (normal) level of the coolant surface; on the inner surface of the immersion tank’s upper lid, e.g., pointing down; or on the bottom inner surface of the immersion tank 102 pointing up, depending on the type of liquid level sensor 120.

[0035] Under normal operating conditions, the computing components 104 are completely immersed in the coolant 110 — that is, the coolant surface level 111 is at or above the level of the upper surface(s) of the computing components 104. Heat emitted by the computing components 104 causes the coolant 110 to evaporate, as indicated by the wavy, upward-pointing arrows in FIG. 1A, dissipating heat. The evaporated or vaporized coolant 113 may circulate or froth above the coolant surface level 111. The vaporized coolant 113 rises until reaching the chilled condenser coil 112, where it condenses. The condensed liquid coolant 110 falls towards the computing components 104 as indicated by the dashed, downward-pointing arrows in FIG. 1A. At the same time, the pump 116 circulates water between the condenser coil 112 and the heat rejection subsystem 118 through the pipes 116. The water transfers the absorbed by the condenser coil 112 from the condensing coolant 110 to the heat rejection sub-system 118 and out of the immersion cooling system 100.

[0036] In operation, the liquid level sensor 124 monitors the level of the coolant 110 in the immersion tank 102 and reports the detected coolant level to the BMC 122. Depending on the type of liquid level sensor 124, the liquid level sensor 124 may report either a representation (e.g., a weight, pressure, or capacitance) of the actual amount or level of liquid coolant 110 in the immersion tank 102 or a binary reading indicating whether or not the coolant level 110 is at or above the normal coolant level 111. At the same time, the temperature sensor 123 monitors the temperature of the computing components 104 and / or of the coolant 110 and reports the detected temperature to the BMC 122. The liquid level sensor 124 and the temperature sensor 123 may report measurements or readings continuously, periodically, or on-demand, e.g., in response to a request from the BMC 122 or another trigger or alert.

[0037] The BMC 122 compares the detected temperature and coolant level to acceptable temperature and coolant level readings, respectively. For instance, the BMC 122 can determine whether the instantaneous temperature and coolant level readings are within acceptable ranges (e.g., at or about 49 °C or within 5 °C, 2 °C, 1 °C, 0.5 °C, or less of 49 °C or another target temperature). The BMC 122 can also maintain and make determinations based on running averages and / or peak measurements of the temperature and coolant level, e.g., over the previous 30 seconds, 1 minute, 5 minutes, 10 minutes, 15 minutes, 1 hour, 2 hours, 4 hours, or longer, to account for noise or other potentially spurious fluctuations. If the measured temperature is relatively stable, then the BMC 122 can sample the temperature sensor 123 and liquid level sensor 124 relatively infrequently (e.g., every 5-10 minutes); if the measured temperature is fluctuating or changing rapidly, then the BMC 122 can sample the temperature sensor 123 and liquid level sensor 124 more frequently (e.g., up to several times per minute).

[0038] If the BMC 122 determines that the detected temperature is too high and / or that the coolant level is too low, e.g., due to a coolant leak 111 as shown in FIG. IB, the BMC 122 triggers the pump 126, which pumps relatively cool liquid coolant 110 from the bottom of the immersion tank 102 to the spray nozzle 128. Put differently, when the BMC 122 registers a low coolant level / high temperature event, it turns on the pump 126 and spray nozzle 128. The spray nozzle 128 discharges or sprays liquid coolant 110 over the exposed surfaces of the computing components 104 to mitigate thermal dryout caused by loss of coolant. This coolant forms droplets and / or a thin layer of liquid coolant 110 on the exposed surfaces of the computing components 104. Heat dissipated through the exposed surfaces of the computing components 104 vaporizes the liquid coolant droplets / layer, and the vaporized coolant rises to the condenser coil 112, transferring heat away from the computing components 104. This spray cooling can protect the computing components 104 from thermal damage for minutes to hours, depending on how quickly the coolant 110 is leaking from the immersion tank 102 and the heat generated by the computing components 104. The temporary thermal protection provided by the spray cooling system 120 allows the computing components 104 to finish their workloads and transfer data outside of the immersion tank 102 so that the computing components 104 can be deenergized and the immersion cooling system 100 can be serviced.

[0039] In addition to triggering the pump 122 in response to high temperature and / or low coolant level, the BMC 122 can also trigger a halt or slowdown of tasks being performed by the computing components 104 and / or a transfer of data or other information from the computing components104 to the outside components or systems. For instance, the computing components 104 can transfer data via the internet or another computer network to another set of computing components in another immersion tank in the same data center or facility or to computing components located at a different facility. The computing components 104 can also signal to outside components or systems that they can no longer accept new tasks or requests. And they can re-assign or request reassignment of pending or queued tasks or requests to outside components or systems, including to other computing components or systems at the same facility. This reduces the effects of the coolant leak 111 on operations performed by the computing components 104 and prevents the coolant leak 111 from interrupting future operations that otherwise might have been performed by the computing components 104.

[0040] For example, if the computing components 104 include servers that host websites, the BMC 122 could initiate a live migration of the websites to servers outside the immersion tank 102. If the computing components 104 are GPUs training a neural network or other machine learning model, however, the BMC 122 may not interrupt or move the training. Instead, the BMC 122 may estimate how long it will take for the GPUs to complete training and adjust the pump rate, etc., based on the expected training completion time, the estimated coolant loss rate, and / or the projected temperature rise rate to keep the GPUs cool enough to complete training without suffering (irreversible) thermal damage. The BMC 122 can also initiate a transfer of fully trained neural networks or other machine-learning models from the GPUs to other devices outside the immersion tank 102.

[0041] The BMC 122 may also send an alert to a site manager or other party responsible for maintaining and / or overseeing the immersion cooling system 100 and / or computing components 104. This may result in a repair, shutdown, or other action intended to fix the coolant leak 111 and / or alleviate problems caused by the coolant leak 111. It may also result in user intervention in the operation of the computing components 104.

[0042] In some cases, the BMC 122 can estimate the rate at which coolant 110 is leaking from the immersion tank 102, e.g., based on the rate at which the temperature is rising and / or the rate at which the coolant level is changing. If the coolant is leaking slowly enough and the temperature is rising slowly enough, then the BMC 122 may not trigger any data transfer or re-assignment of pending or future tasks from the computing components 104. Instead, the BMC 122 may simply alert the site manager or other responsible party while continuing to monitor the temperature and coolant level and, if appropriate, turning on the pump 126.

[0043] Depending on the coolant level and temperature, the BMC 122 can actuate the pump 126 so that the spray nozzle 128 sprays continuously or intermittently, e.g., whenever the measured temperature exceeds a predetermined temperature. The BMC 122 can turn off the pump 126 when the measured temperature falls below that predetermined temperature. Alternatively, the BMC 122 can pulse the pump 126 and spray nozzle 128 on and off periodically, e.g., at a predetermined frequency and / or duty cycle and / or at a frequency and / or duty cycle based on the measured temperature and coolant level, with more frequent and / or longer spray periods for higher temperatures and less frequent and / or shorter spray periods for lower temperatures.Two-Phase Immersion Cooling with Combination Spray Cooling and Coolant Filtration

[0044] FIG. 2 shows a two-phase immersion cooling system 200 with a combination spray cooling and coolant filtration system 220. The two-phase immersion cooling system 200 includes an immersion tank 202 that holds computing components 104 submerged or immersed in two-phase dielectric liquid coolant 110. Heat from the computing components 104 vaporizes the liquid coolant 110, which rises to a condenser coil and condenses, cooling the computing components 104. The pump 116 circulates chilled water or another suitable coolant through the condenser coil 112 and a heat rejection sub-system 118 via pipes 114, transferring the heat from the computing components 104 out of the immersion tank 202 as described above.

[0045] In this example, the immersion tank 202 also holds additional computing components 106 in a zone that is normally filled with vaporized coolant 113. (The immersion tanks in the other two-phase immersion cooling systems disclosed herein can also hold computing components in vaporized coolant above the liquid coolant.) The vaporized coolant 113 has a lower heat capacity than the liquid coolant 110 but can still cool the computing components 106, which may generate less heat than the computing components 104 immersed in the liquid coolant 110. For example, the computing components 106 surrounded by vaporized coolant 113 can include power supplies, backup batteries, or memory components, such as solid-state drives. These computing components tend to generate and throw off less heat than servers or other component components 104 that are typically immersed in the liquid coolant 110.

[0046] The combination spray cooling and coolant filtration system 220 monitors the heat dissipation / removal performance of the two-phase immersion cooling system 200 and provides emergency cooling in the event of a temperature spike or loss of liquid coolant 110 as described above. It also filters impurities out of the liquid coolant 110, both during normal operation and in the event of a temperature spike or loss of liquid coolant 110.

[0047] Like the spray cooling system 120 in FIGS. 1A and IB, the combination spray cooling and coolant filtration system 220 includes a temperature sensor 223 that measures the temperature of the computing components 104 and / or coolant 110 and a liquid level sensor 224 or other sensor that measures the level 111 or amount of liquid coolant 110 in the immersion tank 102. The temperature sensor 223 and liquid level sensor 224 are coupled to a BMC 222 that monitors the temperature and coolant level 111.

[0048] The combination spray cooling and coolant filtration system 220 also includes an inlet 204, inducer 225, pump 226, filter 206, switchable valve 208, and outlet 210. The inlet 204 and outlet 210 are both coupled to the immersion tank 202. In operation, the pump 226 draws liquid coolant 110 from the immersion 202 tank into the inlet 204 and through the inducer 225, which raises the coolant pressure to prevent cavitation, and the filter 206. Under normal operating conditions, the filtered liquid coolant 110 flows back into the immersion tank 202 through the outlet 210 via the valve 208, which is controlled by the BMC 222.

[0049] If the BMC 222 detects a rise in temperature and / or a drop in the coolant level 111, the BMC 222 triggers or actuates the switchable valve 208. (The BMC 222 may also adjust the pump rate, e.g., by changing the voltage supplied to the pump 226.) Instead of directing the filtered liquid coolant 110 through the outlet 210, the valve 208 directs the filtered liquid coolant 110 to a spray nozzle 228, which sprays the liquid coolant 110 onto the computing components 104 and 106, keeping the computing components 104 and 106 cool enough to avoid thermal damage until the temperature rise and / or drop in the coolant level 111 can be addressed. The BMC 222 can also trigger data transfer from and / or interruption of operations by the computing components and send an alert to another system or person as described above.

[0050] Depending on the temperature and coolant level, the BMC 222 can open the valve 208 completely and leave the leave the valve 208 open until the temperature has stabilized at an acceptable level. Alternatively, the BMC 222 can pulse the valve open and closed at a frequency and / or duty cycle selected to keep the computing components 104, 106 cool enough to operate for a period long to complete their ongoing tasks and / or transfer data to devices outside the immersion tank 202. The BMC 222 can also open the valve 208 partway, so that some of the liquid coolant 110 is sprayed through the nozzle 228 and the rest flows through the outlet 210 back into the immersion tank 202.Two-Phase Immersion Cooling with Emergency Spray Cooling and Auxiliary Coolant

[0051] FIG. 3 shows a two-phase immersion cooling system 300 with a spray cooling system 320 that draws extra coolant 110 from an auxiliary or reserve coolant reservoir 330. The two-phase immersion cooling system 300 includes an immersion tank 302 that holds computing components 104 submerged or immersed in two-phase dielectric liquid coolant 110. Heat from the computing components 104 vaporizes the liquid coolant 110, which rises to a condenser coil and condenses, cooling the computing components 104. The pump 116 circulates chilled water or another suitable coolant through the condenser coil 112 and a heat rejection sub-system 118 via pipes 114, transferring the heat from the computing components 104 out of the immersion tank 302 as described above.

[0052] The alternative spray cooling system 320 monitors the heat dissipation / removal performance of the two-phase immersion cooling system 300 and provides emergency cooling in the event of a temperature spike or loss of liquid coolant 110 as described above. Like the spray cooling system 120 in FIGS. 1A and IB, the alternative spray cooling system 320 includes a temperature sensor 323 that measures the temperature of the computing components 104 and / or coolant 110 and a liquid level sensor 324 that measures the level 111 or amount of liquid coolant 110 in the immersion tank 302. The temperature sensor 323 and liquid level sensor 324 are coupled to a BMC 322 that monitors the temperature and coolant level 111.

[0053] If the BMC 322 detects a rise in temperature and / or a drop in the coolant level 111, the BMC 322 triggers or actuates a pump 326 in the auxiliary tank 330 filled with more liquid coolant 110. In FIG. 3, the pump 326 is mounted in the auxiliary tank 330, which may reduce the risk of cavitation if the auxiliary tank 330 is cooler than the immersion tank 302, but the pump 326 can be mounted elsewhere, e.g., in the immersion tank 302 or between the immersion tank 302 and the auxiliary tank 330. An optional inducer (not shown) in the fluid path before the pump 326 can also prevent, reduce, or mitigate cavitation in the pump 326.

[0054] The pump 326 forces the liquid coolant 110 from the auxiliary or reserve tank 130 through a pipe or fluid conduit 327 to a spray nozzle 328, which sprays the liquid coolant 110 onto the exposed surfaces of the computing components 104, keeping the computing components 104 cool enough to avoid thermal damage until the temperature rise and / or drop in the coolant level 111 can be addressed. The BMC 322 can also trigger data transfer from and / or interruption of operations by the computing components as described above.

[0055] At the same time, the BMC 322 can open (and close) a pressure relief valve 304 in the immersion tank 302 to prevent the pressure inside the immersion tank 302 from growing too high due to the introduction of more coolant 110. The pressure relief valve 302 can also be a passive device that opens or vents whenever the pressure inside the immersion tank 302 reaches or exceeds a threshold value. This pressure relief valve 304 prevents the extra coolant sprayed by the spray nozzle 328 from increasing the pressure inside the immersion tank 302 beyond acceptable limits.Two- Phase Immersion Cooling with Spray Nozzle Array

[0056] FIG. 4 shows a two-phase immersion cooling system 400 with a combination spray cooling and coolant filtration system 420 that includes multiple temperature sensors 423a-423c and multiple nozzles 428a-428c, e.g., one temperature sensor 423 and spray nozzle 428 for each computing component 104 or set of computing components 104 / 106. (FIG. 4 shows only three temperature sensors 423a-423c and only three nozzles 428a-428c, but more or fewer temperature sensors and nozzles are possible, and there can be different numbers of temperature sensors and nozzles.) The combination spray cooling and coolant filtration system 420 also includes a BMC 422 that can query or poll the temperature sensors 423 simultaneously or in alternating fashion. For instance, the BMC 422 can poll the temperature sensors 423 in a round-robin fashion. The BMC 422 can average the readings from different temperature sensors 423 as well determine the peak or maximum temperature(s), temperature distribution, and / or the standard deviation or another measure of the dispersion of the temperatures. For spatially distributed temperature sensors 423a-423c as in FIG. 4, the BMC 422 can even estimate or determine the spatial temperature gradient across the immersion tank 402 based on the measured temperatures. The BMC 422 can use this information to determine whether or not to actuate the valve 208 that directs the filtered liquid coolant 110 to the outlet 210 or the spray nozzles 428a-428c and possibly to estimate or identify a possible location of a leak (not shown) in the immersion tank 402 or one of the immersion tank’s seals.

[0057] When the valve 208 is actuated, the pump 226 supplies the spray nozzles 428 with liquid coolant 110 (in other versions, there can be multiple pumps, e.g., one pump per spray nozzle or subset of spray nozzles). Each spray nozzle 428 includes or is coupled to a corresponding solenoid valve or other suitable valve that is operably coupled to and controlled by the BMC 422. The BMC 422 can actuate these valves and spray nozzles (and / or corresponding pumps) to direct the spray to hotter computing components 104 based on temperature measurements and / or other information (e.g., spatial temperature gradient) derived from the temperature and liquid level measurements.For example, then the BMC 422 may actuate the valves and / or spray nozzles to spray (more) liquid coolant 110 on or toward the hottest computing component(s) 104 and 106 or area(s) of the immersion tank 102. The other nozzles 428 can be turned off or set to lower spray rates. The nozzles 428 can be actuated together or pulsed on and off independently at different times, frequencies, duty cycles, and durations depending on the temperatures of the components 104 that they cool.Single-Phase Immersion Cooling with Emergency Spray Cooling

[0058] FIGS. 5 A and 5B show a single-phase immersion cooling system 500 with a spray cooling system 520 for cooling exposed computing components in the event of coolant loss due to a leak or other emergencies. Like the two-phase immersion systems described above, the single-phase immersion cooling system 500 includes a sealed immersion tank 502 that holds one or more computing components 104, such as servers, graphics processing units (GPUs), memory, power supplies, or switches, which are operably connected to other computing components or systems outside the immersion tank 502. The computing components 104 are immersed in thermally conductive dielectric liquid coolant 510, or coolant 510, such as a fluorochemical with higher viscosity than the coolant used for two-phase immersion cooling. The coolant 510 absorbs the heat dissipated by the computing components 104, keeping the computing components 104 cool enough to operate efficiently and below their thermal damage threshold.

[0059] Like other single -phase immersion cooling systems, the single-phase immersion cooling system 500 shown in FIGS. 5A and 5B includes a pump 526 that circulates the liquid coolant 510 through a heat exchanger 530 via an inlet 521 and an outlet 529 that open into the immersion tank 502. Warm coolant enters the inlet 521, is pumped through the heat exchanger 530, where it transfers heat to chilled water or another chilled coolant 532. The pump 526 forces the cooled liquid coolant 510 out of the heat exchanger 530 and through the outlet 529 back into the immersion tank 502 via a valve 508, removing heat from inside the immersion tank 502 and keeping the computing components 104 cool.

[0060] The spray cooling system 520 distinguishes the single-phase immersion cooling system 500 from other single-phase immersion cooling systems. The spray cooling system 520 includes a BMC 522 that is operably coupled to a temperature sensor 523, a liquid level sensor or other sensor (not shown), and the valve 508, which is connected to both the outlet 529 and one or more spray nozzles 528. (FIGS. 5A and 5B show only a single spray nozzle 528, both other single-phase immersion cooling systems may include multiple (possibly independently actuated) spray nozzles,e.g., as described above with respect to FIG. 4.) The BMC 522 operates like the BMCs described above can also be operably coupled to the pump 526, the computing components 104, and computing components or systems outside immersion tank 502.

[0061] FIGS. 5 A and 5B also show the single-phase immersion cooling system 500 with an optional condenser coil 512 filled with chilled water or another suitable chilled fluid. Pipes or conduits 514 and a pump 516 connect the condenser coil 512 to a heat rejection sub-system 518, such as a heat exchanger, chilled water loop, evaporative cooling tower, dry cooler, or other suitable mechanism for dissipating heat. The condenser coil 512 can be used to dissipate heat during normal operation and / or to cool vaporized coolant when the spray cooling system 520 is cooling the computing components 104.

[0062] Normally, the computing components 104 are completely submerged in the coolant 510, which cools the computing components 104 via the heat exchanger 530 as described above. Put differently, the coolant surface level 511 is at or above the level of the upper surface(s) of the computing components 104. The liquid level sensor monitors the level of the coolant 510 in the immersion tank 502 and reports the detected coolant level to the BMC 522. At the same time, the temperature sensor 523 monitors the temperature of the computing components 104 and / or of the coolant 510 and reports the detected temperature to the BMC 122. The liquid level sensor and the temperature sensor 523 may report measurements or readings continuously, periodically, or on- demand, e.g., in response to a request from the BMC 522 or another trigger or alert.

[0063] If the coolant 510 leaks out of the immersion tank 502, e.g., due to a faulty seal between the immersion tank 502 and the inlet 521 or outlet 529, the liquid level sensor may detect a drop in the coolant level and / or the temperature sensor 523 may detect an increase in temperature. The BMC 522 compares the detected temperature and coolant level to acceptable temperature and coolant level readings, respectively, e.g., as described above with respect to FIGS. 1A and IB.

[0064] If the BMC 522 determines that the detected temperature is too high and / or that the coolant level is too low, e.g., due to a coolant leak, the BMC 522 actuates the valve 508, which directs the liquid coolant 510 from the heat exchanger 530 through the spray nozzle 528 instead of the outlet 529. The spray nozzle 528 discharges or sprays liquid coolant 510 over the exposed surfaces of the computing components 104 to mitigate thermal dryout caused by loss of coolant. This coolant forms droplets and / or a thin layer of liquid coolant 510 on the exposed surfaces of the computing components 104, cooling the computing components 104.

[0065] Depending on the conditions (e.g., temperature and pressure) within the immersion tank 502 and the liquid coolant 510, the coolant droplets on the hot computing components 104 can vaporize and rise to the top of the immersion tank 502. An optional pressure relief valve 504 can release at least some of the vaporized coolant from the immersion tank 502 to prevent the pressure within the immersion tank 502 from getting too high. If the single-phase immersion cooling system 500 includes the optional condenser coil 512, then the vaporized coolant may condense and fall back down to the computing components 104 in liquid form as described above with respect to FIGS. 1A and IB.

[0066] As above, spray cooling can protect the computing components 104 from thermal damage for minutes to hours, depending on how quickly the coolant 510 is leaking from the immersion tank 502. The temporary thermal protection provided by the spray cooling system 520 allows the computing components 104 to finish their workloads and transfer data outside of the immersion tank 502 so that the computing components 104 can be deenergized and the immersion cooling system 500 can be serviced.Alternative Coolant Sensors

[0067] In addition to or instead of the liquid level sensors described above, each of the inventive spray cooling systems disclosed herein can include a load or pressure sensor (not shown) mounted underneath or at the bottom of the immersion tank and operably coupled to the BMC. In operation, this load or pressure sensor can measure the mass or weight of the immersion tank and its contents, including the coolant. A drop in weight may indicate that coolant is leaking or has leaked out of the immersion tank. If this weight reduction accompanies a rise in temperature, then the BMC may trigger spray cooling by the pump and nozzle(s) to keep the computing components cool and prevent thermal damage and data transfer to avoid interrupting operations as explained above.

[0068] Other sensors for measuring the amount of (liquid) coolant in the immersion tank are also possible. For instance, the spray cooling system can include a pressure sensor that measures the pressure within the immersion tank. Under normal operating conditions, the amount of coolant within the immersion tank should be constant, so the immersion tank’s internal pressure should be a function of its temperature. If the pressure sensor measures an internal pressure that is lower than the expected internal pressure at a given temperature, then the BMC may determine that coolant has leaked or is leaking out of the immersion tank and trigger spray cooling as explained above. Likewise, the spray cooling system can include an oxygen sensor that measures the oxygen contentwithin the immersion tank. If the measurement falls outside of the accepted range, the BMC can trigger spray cooling.

[0069] The spray cooling system can also include a camera to image the inside of the immersion tank. The images acquired by the camera can be inspected by a person or by a machine-learning model, such as an artificial neural network, running on the BMC or a processor coupled to the BMC and trained to determine if the liquid level is below the top surfaces of the computing components. For instance, the machine-learning model may be trained to recognize when the computing components are not completely submerged in the liquid coolant or the froth layer (vaporized coolant) is too low. Again, if the liquid level is too low, then the BMC can trigger spray cooling.Conclusion

[0070] While various inventive embodiments have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and / or structures for performing the function and / or obtaining the results and / or one or more of the advantages described herein, and each of such variations and / or modifications is deemed to be within the scope of the inventive embodiments described herein. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and / or configurations will depend upon the specific application or applications for which the inventive teachings is / are used. Those skilled in the art will recognize or be able to ascertain, using no more than routine experimentation, many equivalents to the specific inventive embodiments described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that inventive embodiments may be practiced otherwise than as specifically described. Inventive embodiments of the present disclosure are directed to each individual feature, system, article, material, kit, and / or method described herein. In addition, any combination of two or more such features, systems, articles, materials, kits, and / or methods, if such features, systems, articles, materials, kits, and / or methods are not mutually inconsistent, is included within the inventive scope of the present disclosure.

[0071] Also, various inventive concepts may be embodied as one or more methods, of which an example has been provided. The acts performed as part of the method may be ordered in any suitable way. Accordingly, embodiments may be constructed in which acts are performed in anorder different than illustrated, which may include performing some acts simultaneously, even though shown as sequential acts in illustrative embodiments.

[0072] All definitions, as defined and used herein, should be understood to control over dictionary definitions, definitions in documents incorporated by reference, and / or ordinary meanings of the defined terms.

[0073] Unless stated otherwise, the terms “approximately” and “about” are used to mean within ± 20% of a target (e.g., dimension or orientation) in some embodiments, within ± 10% of a target in some embodiments, within ± 5% of a target in some embodiments, and yet within ± 2% of a target in some embodiments. The terms “approximately” and “about” can include the target. The term “essentially” is used to mean within ± 3% of a target.

[0074] The indefinite articles “a” and “an,” as used herein, unless clearly indicated to the contrary, should be understood to mean “at least one.”

[0075] The phrase “and / or,” as used herein, should be understood to mean “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Multiple elements listed with “and / or” should be construed in the same fashion, i.e., “one or more” of the elements so conjoined. Other elements may optionally be present other than the elements specifically identified by the “and / or” clause, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, a reference to “A and / or B”, when used in conjunction with open-ended language such as “comprising” can refer, in one embodiment, to A only (optionally including elements other than B); in another embodiment, to B only (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc.

[0076] As used herein, “or” should be understood to have the same meaning as “and / or” as defined above. For example, when separating items in a list, “or” or “and / or” shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one, of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as “only one of’ or “exactly one of’ or “consisting of,” will refer to the inclusion of exactly one element of a number or list of elements. In general, the term “or” as used herein shall only be interpreted as indicating exclusive alternatives (i.e., “one or the other but not both”) when preceded by terms of exclusivity, such as “either,” “one of,” “only one of,” or “exactly one of.” “Consisting essentially of,” shall have its ordinary meaning as used in the field of patent law.

[0077] As used herein, the phrase “at least one,” in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase “at least one” refers, whether related or unrelated to those elements specifically identified. Thus, as a nonlimiting example, “at least one of A and B” (or, equivalently, “at least one of A or B,” or, equivalently “at least one of A and / or B”) can refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc.

[0078] In the specification above, all transitional phrases such as “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” “holding,” “composed of,” and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases “consisting of’ and “consisting essentially of’ shall be closed or semi-closed transitional phrases, respectively, as set forth in the United States Patent Office Manual of Patent Examining Procedures, Section 2111.03.

Claims

CLAIMS1. A system comprising: an immersion tank to hold a computing component in a liquid coolant; a sensor to sense a level of the liquid coolant in the immersion tank; a temperature sensor to sense a temperature of the computing component and / or of the liquid coolant; a spray nozzle, disposed in the immersion tank, to spray the liquid coolant on the computing component in case of a liquid coolant loss; a pump, in fluid communication with the liquid coolant and spray nozzle, to pump the liquid coolant through the spray nozzle; and a controller, operably coupled to the pump, the sensor, and the temperature sensor, to actuate the spray nozzle in response to an indication from the sensor that the level of the liquid coolant in the immersion tank is below a predetermined level and / or an indication from the temperature sensor that the temperature of the computing component and / or of the liquid coolant is above a predetermined temperature.

2. The system of claim 1, wherein the liquid coolant is a thermally conductive dielectric liquid coolant.

3. The system of claim 1, wherein the spray nozzle is configured to spray the liquid coolant on a surface of the computing component exposed by a drop in the level of the liquid coolant.

4. The system of claim 1, wherein the spray nozzle is a first spray nozzle in a plurality of spray nozzles configured to spray the liquid coolant on a surface of the computing component.

5. The system of claim 4, wherein the controller is configured to determine a temperature gradient within the immersion tank and to actuate the plurality of spray nozzles based on the temperature gradient.

6. The system of claim 1, wherein the controller is further configured to adjust a pump rate of the pump to prevent or reduce cavitation of the liquid coolant in the pump.

7. The system of claim 1, wherein the controller is further configured to trigger transfer of data from the computing component to another computing component outside the immersion tank in response to the indication from the sensor that the level of the liquid coolant in the immersion tank is below a predetermined level and / or the indication from the temperature sensorthat the temperature of the computing component and / or of the liquid coolant is above a predetermined temperature.

8. The system of claim 1, wherein the controller is further configured to trigger reassignment of at least one pending task from the computing component to another computing component outside the immersion tank in response to the indication from the sensor that the level of the liquid coolant in the immersion tank is below a predetermined level and / or the indication from the temperature sensor that the temperature of the computing component and / or of the liquid coolant is above a predetermined temperature.

9. The system of claim 1, wherein the controller is further configured to trigger re-direction of at least one incoming task from the computing component to another computing component outside the immersion tank in response to the indication from the sensor that the level of the liquid coolant in the immersion tank is below a predetermined level and / or the indication from the temperature sensor that the temperature of the computing component and / or of the liquid coolant is above a predetermined temperature.

10. The system of claim 1, wherein the controller is further configured to issue an alert in response to the indication from the sensor that the level of the liquid coolant in the immersion tank is below a predetermined level and / or the indication from the temperature sensor that the temperature of the computing component and / or of the liquid coolant is above a predetermined temperature.

11. The system of claim 1, wherein the predetermined level is at or below an upper surface or edge of the computing component.

12. The system of claim 1, further comprising: a condenser coil, disposed in the immersion tank above the computing component, to condense liquid coolant vaporized by heat emitted by the computing component.

13. The system of claim 1, further comprising: an auxiliary tank, in fluid communication with the immersion tank via the spray nozzle, to supply additional liquid coolant.

14. The system of claim 1, further comprising: a coolant filtration system, in fluid communication with the immersion tank via the spray nozzle, to filter the liquid coolant.

15. The system of claim 14, wherein the coolant filtration system comprises: an outlet, in fluid communication with the immersion tank, to dispense filtered liquid coolant into the immersion tank; and a valve, in fluid communication with the outlet and the spray nozzle and operably coupled to the controller, to direct the filtered liquid coolant to the immersion tank via the outlet or the spray nozzle in response to actuation by the controller.

16. The system of claim 1, further comprising: an inducer, in fluid communication with the pump, to raise a pressure of the liquid coolant entering the pump.

17. The system of claim 1, further comprising: a pressure relief valve, in fluid communication with the immersion tank, to relieve pressure within the immersion tank.

18. A method of cooling a computing component immersed in liquid coolant in an immersion tank, the method comprising: sensing a level of the liquid coolant in the immersion tank; sensing a temperature of the computing component and / or of the liquid coolant; determining that the level of liquid coolant in the immersion tank is below a predetermined level and / or the temperature of the computing component and / or of the liquid coolant is above a predetermined temperature; and in response to determining that the level of liquid coolant in the immersion tank is below the predetermined level and / or that the temperature of the computing component and / or of the liquid coolant is above the predetermined temperature, spraying the liquid coolant on the computing component to cool the computing component.

19. The method of claim 18, wherein sensing the temperature of the computing component and / or of the liquid coolant comprises sensing the temperature at each of plurality of locations within the immersion tank.

20. The method of claim 18, wherein spraying the liquid coolant comprises pumping the liquid coolant in the immersion tank through a spray nozzle onto an exposed surface of the computing component.

21. The method of claim 18, wherein spraying the liquid coolant comprises pumping the liquid coolant from an auxiliary tank through a spray nozzle onto an exposed surface of the computing component.

22. The method of claim 18, wherein spraying the liquid coolant comprises actuating a valve to direct the liquid coolant from a filter through a spray nozzle.

23. The method of claim 18, wherein spraying the liquid coolant comprises directing the liquid coolant through each of a plurality of spray nozzles in the immersion tank.

24. The method of claim 23, wherein directing the liquid coolant through each of a plurality of spray nozzles in the immersion tank comprises independently actuating each of the plurality of spray nozzles.

25. The method of claim 18, wherein spraying the liquid coolant allows the computing component to complete a computing task being performed by the computing component without experiencing thermal damage.

26. The method of claim 18, further comprising: in response to determining that the level of liquid coolant in the immersion tank is below the predetermined level and / or that the temperature of the computing component and / or of the liquid coolant is above the predetermined temperature, transferring data from the computing component to another computing component outside the immersion tank.

27. The method of claim 18, further comprising: in response to determining that the level of liquid coolant in the immersion tank is below the predetermined level and / or that the temperature of the computing component and / or of the liquid coolant is above the predetermined temperature, re-assigning at least one pending task from the computing component to another computing component outside the immersion tank.

28. The method of claim 18, further comprising: in response to determining that the level of liquid coolant in the immersion tank is below the predetermined level and / or that the temperature of the computing component and / or of the liquid coolant is above the predetermined temperature, re-directing incoming tasks from the computing component to another computing component outside the immersion tank.

29. The method of claim 18, further comprising: issuing an alert in response to determining that the level of liquid coolant in the immersion tank is below the predetermined level and / or that the temperature of the computing component and / or of the liquid coolant is above the predetermined temperature.

30. A system comprising:an immersion tank to hold computing components in a liquid coolant, heat generated by the computing components causing the liquid coolant to evaporate; a condenser coil, disposed in the immersion tank above the computing components and the liquid coolant, to condense evaporated coolant; a sensor to sense a level of the liquid coolant in the immersion tank; temperature sensors to sense temperatures of the computing components and / or of the liquid coolant; spray nozzles, disposed in the immersion tank, to spray the liquid coolant on the computing components in case of a liquid coolant loss; a pump, in fluid communication with the liquid coolant and spray nozzles, to pump the liquid coolant through the spray nozzles; and a controller, operably coupled to the pump, the sensor, and the temperature sensors, to actuate the spray nozzles and to issue an alert in response to an indication from the sensor that the level of the liquid coolant in the immersion tank is below a predetermined level and / or an indication from the temperature sensors that at least one of the temperatures of the computing components and / or of the liquid coolant is above a predetermined temperature.

Images