Coolant vapor handling for immersion-cooling systems

Abstract

A bellows assembly and related methods are described. The bellows assembly can be used in a two-phase immersion-cooling system to regulate pressure in an immersion tank's headspace above a coolant liquid. The bellows assembly can include a flexible container and valves to reduce emissions of coolant-liquid vapor into an ambient environment. The bellows assembly can further include a drain port to recover coolant-liquid condensate. Also described are a dehumidifier and gas replacement system for use in an immersion cooling system. The dehumidifier can be fluidically coupled to a headspace of the immersion tank to capture and remove water molecules from inside immersion tank. The gas replacement system can supply a dry gas into the immersion tank to replace removed water molecules and other gases, such as oxygen, removed from the tank.

Description

Coolant Vapor Handling for Immersion-Cooling SystemsCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims a priority benefit, under 35 U.S.C. § 119(e), to U.S. provisional application Ser. No. 63 / 590,683 filed on October 16, 2023, titled “Bellows for Immersion-Cooling System,” and to U.S. provisional application Ser. No. 63 / 601,284 filed on November 21, 2023, titled “Environmental Dehumidifier in Two-Phase Systems,” both of which applications are incorporated herein by reference in their entirety.BACKGROUND

[0002] As feature sizes and transistor sizes have decreased for integrated circuits (ICs), the amount of heat generated by a single chip, such as a microprocessor, has increased. Chips that once were air cooled have evolved to chips needing more heat dissipation than can be provided by air alone. In some cases, immersion cooling of chips in a coolant liquid is employed to maintain IC chips at appropriate operating temperatures.

[0003] Two-phase immersion cooling is a liquid cooling technique that utilizes a liquid-togas phase transition to remove heat from a heat-generating component, such as a processor or, more generally, an electronic device of a computing system. This is typically accomplished using a tank to submerge the heat-generating component in a bath of coolant liquid where the coolant liquid is a dielectric with a relatively low boiling point (e.g., 50°C). During operation, the coolant liquid in direct contact with the heat-generating component boils, producing coolant-liquid vapor that rises upwards within the tank and accumulates above the bath of coolant liquid. The coolant-liquid vapor thereafter transfers heat when condensing to liquid on condensers disposed above the coolant liquid. The condensed liquid can fall from the condensers into the bath of coolant liquid below. A two-phase immersioncooling system can be used to cool high-density computing systems, such as an array of servers in a data center.SUMMARY

[0004] The present disclosure relates to a bellows assembly that can be used for pressure regulation and that allows for gas expansion and gas containment in two-phase immersioncooling systems, and in some instances in single-phase immersion-cooling systems. The bellows assembly comprises a container having at least one flexible, polymeric wall that can deform outward from a center of the bellows and deform inward to change an amount of volume enclosed by the container. Hardware elements (such as mounting hardware,pressure-relief vent(s), and / or port(s)) can be mounted on the container. The bellows pressure-relief vent(s) and valves can be arranged to reduce an amount of coolant-liquid vapor released from the container during an overpressure event and during opening of tank containing the coolant-liquid bath and computing components being cooled. The bellows assembly can also be adapted to capture condensed coolant liquid in the bellows and returned the captured liquid to the tank.

[0005] The present disclosure also relates to mitigating unwanted effects of humidity and non-condensable gases (NCGs) in an immersion-cooling tank. The inventors have recognized and appreciated that humidity can be introduced into an immersion tank either by opening the tank for servicing or by air ingestion during events causing negative pressure inside the immersion tank during operation of the immersion-cooling system. Water vapor in the tank may cause chemical interactions with the coolant liquid and create an acid that can be corrosive to at least some of the hardware in the tank. The presence of oxygen in the air may also cause oxidative effects on certain immersion fluids and byproducts of immersion fluid decomposition. Unwanted effects of humidity and non-condensable gases (NCGs) in an immersion-cooling tank can be mitigated in several ways: (1) incorporating an atmospheric management of the vapor space of a two-phase immersion tank that utilizes dehumidification, and (2) managing non-condensable gasses by either selective purging and / or replacement with selected dry gasses (e.g., nitrogen or argon).

[0006] Some implementations relate to methods of cooling semiconductor dies in an immersion tank of a two-phase immersion-cooling system. Such methods can include acts of: receiving heat from the semiconductor dies into a coolant liquid within the immersion tank, the coolant liquid filling a portion of the immersion tank below a headspace that occupies a top region of the immersion tank, the headspace filling a first portion of a first volume that is normally closed and contains a gas when the two-phase immersion-cooling system is operating; and receiving a first amount of the gas from the headspace into a second volume enclosed by a container of a bellows assembly in response to an increase in pressure of the gas in the headspace, wherein the second volume comprises a second portion of the first volume. The bellows assembly can comprise: the container, a gas port mounted in the container and fluidically coupled to the headspace, and an isolation valve fluidically coupled between the gas port and the headspace. Methods of cooling semiconductor dies can further comprise acts of: deforming a first wall of the container in a first direction to increase the second volume while receiving the first amount of the gas; detecting, by a controller of thetwo-phase immersion-cooling system, an event that would allow a second amount of the gas from the second volume to flow into the headspace and displace a third amount of the gas from the headspace into an ambient environment around the immersion tank; and closing the isolation valve to isolate the second volume from the headspace in response to detecting the event to prevent at least a portion of the second amount of the gas from flowing into the headspace and causing displacement of the third amount of the gas from the headspace into the ambient environment.

[0007] Some implementations relate to two-phase immersion-cooling systems comprising: an immersion tank to contain one or more printed circuit boards having semiconductor dies to be cooled via two-phase immersion cooling during operation of the semiconductor dies, and a bellows assembly to fluidically couple to a headspace within the immersion tank and form a normally-closed first volume that includes the headspace to contain a gas during operation of the two-phase immersion-cooling system. The bellows assembly can comprise: a container comprising a polymer and enclosing a second volume that is a portion of the first volume, the container having a first surface spanning a first surface area that encloses the second volume, wherein at least a portion of the container is reversibly deformable to increase and decrease an amount of the second volume enclosed by the container; a first wall comprising the polymer and having a second surface spanning a second surface area; a second wall having a third surface spanning a third surface area, wherein the second surface area and the third surface area comprise a majority of the first surface area; and a gas port mounted to the container to admit a first amount of the gas into the second volume from the headspace within the immersion tank when the gas in the headspace is at a first pressure that is higher than a second pressure of the gas in the second volume, wherein the gas port can further admit a second amount of the gas from the second volume into the headspace when the first pressure is lower than the second pressure. The two-phase immersion-cooling systems can further comprise a controller, and an isolation valve to fluidically couple between the immersion tank and the bellows assembly, wherein the controller is configured to issue a command to close the isolation valve to isolate the second volume from the headspace in response to the controller detecting an event that would allow a third amount of the gas from the second volume to displace a fourth amount of the gas from the headspace into an ambient environment around the immersion tank if the isolation valve were not closed.

[0008] Some implementations relate to immersion-cooling systems comprising: an immersion tank to hold at least one computing component immersed in a coolant liquidwithin the immersion tank; a dehumidifier fluidically coupled to a headspace of the immersion tank, the dehumidifier configured to capture water molecules from a gas mixture in the headspace of the immersion tank; and a gas replacement chamber, fluidically coupled to the immersion tank, configured to supply a first amount of a dry gas to replace the water molecules captured from the gas mixture in the headspace of the immersion tank.

[0009] Some implementations relate to methods of removing water molecules from a gas mixture in a headspace of an immersion tank. Such methods can comprise acts of cooling at least one computer component with a coolant liquid in the immersion tank; capturing the water molecules with a dehumidifier that is fluidically coupled to a headspace of the immersion tank; and admitting a first amount of dry gas into the headspace to replace the water molecules captured from the gas mixture, wherein the first amount of dry gas is admitted from a gas replacement chamber that is fluidically coupled to the immersion tank.

[0010] Some implementations relate to methods of filling an immersion tank of an immersion-cooling system with coolant liquid to cool at least one computing component. The immersion-cooling system can comprise: the immersion tank, a dehumidifier fluidically coupled to a headspace of the immersion tank, the dehumidifier configured to capture water molecules from a gas mixture in the headspace of the immersion tank, a gas replacement chamber, fluidically coupled to the immersion tank, configured to supply a first amount of a dry gas to replace the water molecules captured from the gas mixture in the headspace of the immersion tank, and an auxiliary chamber fluidically coupled to the immersion tank and configured to at least partially fill the immersion tank with the coolant liquid. Methods of filling the tank with coolant liquid can comprise acts of prior to filling the immersion tank with the coolant liquid, operating the dehumidifier to capture the water molecules from the gas mixture in at least the headspace of the immersion tank and from components in the immersion tank; supplying at least the first amount of the dry gas into the immersion tank; and after operating the dehumidifier for a period of time, filling the immersion tank with the coolant liquid from the auxiliary chamber.

[0011] 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

[0012] 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).

[0013] FIG. 1 depicts a two-phase immersion-cooling system to remove heat from semiconductor dies during operation of the semiconductor dies.

[0014] FIG. 2A illustrates, with a semi-transparent perspective view, an example of a bellows assembly that can be used with the immersion-cooling system of FIG. 1.

[0015] FIG. 2B depicts an enlarged view (in cross-section) of one example of mounting hardware elements that can be included in the bellows assembly of FIG. 2A.

[0016] FIG. 2C depicts an additional example of mounting hardware elements that can be included in the bellows assembly of FIG. 2A.

[0017] FIG. 2D depicts a cross-section of the container, taken at the location indicated by the dashed line in FIG. 2A.

[0018] FIG. 2E depicts deformation of walls of the container of FIG. 2A when the pressure of gas within the container increases beyond the ambient pressure outside the container.

[0019] FIG. 2F depicts deformation of walls of the container of FIG. 2A when the pressure of gas within the container decreases below the ambient pressure outside the container.

[0020] FIG. 2G depicts another implementation of a bellows assembly that can be used with the immersion-cooling system of FIG. 1.

[0021] FIG. 3A depicts an example of port components and a vapor barrier that can be used with the bellows assembly of FIG. 2A.

[0022] FIG. 3B illustrates an example of a port insert that can be used in the assembly of FIG. 3A

[0023] FIG. 3C depicts an additional example of port components and a vapor barrier that can be used with the bellows assembly of FIG. 2A.

[0024] FIG. 3D illustrates an example of an exterior port insert that can be used in the assembly of FIG. 3C.

[0025] FIG. 3E illustrates an example of a port in perspective view.

[0026] FIG. 3F depicts an example of a burst valve that can be used with the bellows assembly of FIG. 2A and FIG. 2G.

[0027] FIG. 3G depicts a flange assembly that includes a burst valve and a drain port. The flange assembly can be used with the bellows assembly of FIG. 2A and FIG. 2G.

[0028] FIG. 3H depicts a portion of the flange of FIG. 3G in plan view.

[0029] FIG. 4A depicts one arrangement of a heating element that can be used to provide heat to the bellows assembly of FIG. 2A and FIG. 2G.

[0030] FIG. 4B depicts an additional arrangement of a heating element that can be used to provide heat to the bellows assembly of FIG. 2A and FIG. 2G.

[0031] FIG. 5A illustrates an insulating enclosure that can be placed around the bellows assembly of FIG. 2A and FIG. 2G.

[0032] FIG. 5B illustrates an additional implementation of an insulating enclosure that can be placed around the bellows assembly of FIG. 2A and FIG. 2G.

[0033] FIG. 5C illustrates an additional implementation of an insulating enclosure that can be placed around the bellows assembly of FIG. 2A and FIG. 2G.

[0034] FIG. 5D illustrates an additional arrangement to provide heated to gas within the bellows assembly of FIG. 2A and FIG. 2G.

[0035] FIG. 6A depicts structure that can be used to support the bellows assembly of FIG. 2A and FIG. 2G

[0036] FIG. 6B depicts a further example of supporting the bellows assembly of FIG. 2A and FIG. 2G

[0037] FIG. 7 depicts a further example of supporting the bellows assembly of FIG. 2A andFIG. 2G

[0038] FIG. 8 depicts a two-phase immersion-cooling system with a compressor dehumidifier and a gas management system.

[0039] FIG. 9 depicts a two-phase immersion-cooling system with a compressor dehumidifier and a gas management system. The tank of the two-phase immersion-cooling system is fluidically coupled to an auxiliary tank.

[0040] FIG. 10 depicts a two-phase immersion-cooling system with a desiccant dehumidifier and a gas management system.

[0041] FIG. 11 depicts a two-phase immersion-cooling system with a desiccant dehumidifier and a gas management system. The tank of the two-phase immersion-cooling system is fluidically coupled to an auxiliary tank.DETAILED DESCRIPTION

[0042] 1. Immersion-Cooling System with Bellows and Isolation Valve

[0043] FIG. 1 depicts a two-phase immersion-cooling system 100 that can remove heat from semiconductor dies 180 during operation of the semiconductor dies. The immersion-cooling system 100 includes an immersion tank 110 containing a coolant liquid 150 that fills a first portion of the tank’s enclosed volume 112. Above the coolant liquid 150 is an air space (also referred to as a “headspace” 114) filling a second portion of the tank’s volume 112. A condenser 132 can be located in the headspace 114 to condense coolant-liquid vapor 140 rising from the coolant liquid 150. The condenser 132 can comprise a thermally-conductive conduit (such as a pipe or tube) that carries a coolant that is circulated through the condenser 132 by pump connected to a chiller 130 or other suitable mechanism for dissipating heat from the circulating coolant.

[0044] A bellows assembly 120 can be fluidically coupled to the headspace 114 of the tank 110. Gas from the headspace 114 can be received into a bellows volume 122 enclosed by the bellows assembly 120 when pressure of the gas in the headspace 114 increases. Additionally, gas can be expelled from the volume 122 and returned to the headspace 114 when pressure of the gas in the headspace 114 decreases. The tank 110 and bellows assembly 120 are coupled by at least one gas port 124 in a way to form a normally-closed system for gas within the headspace 114 and bellows volume 122. Further examples of the use of bellows in immersion cooling may be found in U.S. non-provisional patent application No. 18 / 318,870, filed May 17, 2023, now issued as U.S. patent 11,997,825; application No. 18 / 318,888, filed May 17, 2023, now issued as U.S. patent 11,825,631; application No. 18 / 318,905, filed May 17, 2023, now issued as U.S. patent 11,792,956; application No. 18 / 487,782, filed October16, 2023, and international patent application No. PCT / US2023 / 067056, filed May 16, 2023, which applications are incorporated by reference herein in their entirety.

[0045] In some implementations, one or more isolation valves 125 can be located between the tank 110 and the bellows assembly 120, such that the bellows volume 122 can be valved off and isolated from the headspace 114 in the tank. However, in some implementations, isolation valve(s) 125 may not be included in the system. The valve(s) can be manual valves or automated valves.

[0046] The tank 110 can include an access door 111, which may be located on the top or side of the tank. The access door 111 can be used to install, swap, and / or remove circuit boards (PCBs) 160 within the tank 110. In some cases, the PCBs can be hot-swapped (exchanged while the immersion-cooling system is in operation and other PCBs 160 are running and being cooled). A PCB 160 to be exchanged can be shut down and removed through the access door 111. The access door 111 can slide (e.g., move laterally using rollers) to open rather than swing open to reduce turbulence in the headspace 114 that would eject coolantliquid vapor from the tank 110. In some cases, the access door 111 can be hinged and swing open.

[0047] Because the headspace 114 and bellows volume 122 can be under pressure when the system is operating, it can be beneficial to valve off the bellows volume 122 before opening the access door 111. Isolating the bellows volume 122 with the isolation valve(s) 125 can prevent pressure and / or the heavier coolant-liquid vapor from entering the headspace 114 when the access door is opened and forcing coolant-liquid vapor out of the tank 110. For example, if the isolation valve(s) were not closed prior to opening the access door 111, gas within the bellows container 210 could flow back into the headspace displacing gas from the headspace out the passageway of the (in this case, open) access door 111 and into the ambient environment around the tank. Such displacement of gas, which can contain coolant-liquid vapor, into the ambient environment is undesirable. Further, the flexible container 210 may collapse in part due to its own weight and result in further displacement of gas from the headspace.

[0048] The closing and opening of isolation valve(s) 125 can be manual in some implementations. In other implementations, a sensor 116 can be included in the immersioncooling system 100 to detect when the access the access door 111 is being opened. For example, the sensor may detect motion or an unlocking of the access door 111. A signal from the sensor 116 can be received and processed by a controller 118, which can issue acommand signal that causes the isolation valve(s) 125 to close. For example, the isolation valve(s) 125 can be driven by electromagnetic actuator(s) (e.g., stepper motor or solenoid) that are activated in response to the command signal. The controller 118 can be programmed to further issue a command signal to open the isolation valve(s) 125 in response to receiving a signal from the sensor 116 indicating that the access door 111 is closed.

[0049] Any suitable valve can be used for the isolation valve(s) 125. One example valve is a butterfly valve, which may be automatically closed and opened with a motor or other actuator or manually operated by a user to open and close the valve. Another example valve is a ball valve, which also can be automatically closed and open or manually operated. Another example valve is a sliding gate valve, which also can be automatically closed and opened with a motor or other actuator or manually operated by a user. Other types of valves (which can also be operated automatically or manually) that can be used for the isolation valve(s)125 include needle valves, globe valves, diaphragm valves, and pinch valves. The isolation valve 125 is not limited to only the types of valves listed here.

[0050] The immersion-cooling system 100 can include one or more pressure-release valves126 to release gas when a pressure in the headspace 114 and / or bellows volume 122 exceeds a first predetermined threshold e.g., during an overpressure event). The bellows volume 122 acts as a secondary containment unit that assists in the normal operation of the two-phase immersion-cooling system 100 and also accommodates a significant portion if not all of the volume of air, air / vapor mixture in the tank’s headspace 114 with an intention to avoid or significantly reduce the loss of coolant-liquid vapor 140 from the immersion-cooling system 100 during an overpressure event, as described in further detail below. The immersioncooling system 100 may or may not further include a bellows heater 190, depicted as a heating coil 192 in the illustration of FIG. 1.

[0051] The immersion-cooling system 100 can further include one or more burst valves 128. In FIG. 1, a burst valve 128 can be located on a wall of the bellows container 210, but the location of the burst valve is not so restricted. A burst valve 128 can be located elsewhere on the immersion-cooling system 100, as described elsewhere herein, provided the burst valve 128 is in fluid communication with the tank’s headspace 114 and / or the volume 122 within the bellows container 210. The burst valve(s) 128 can be included in a bellows assembly to prevent damage to the bellows container 210. For example, if the pressure-release valve(s) 126 on the system fail, there is a chance that the container 210 could rupture during an overpressure event. To reduce or eliminate the chance of container rupture, the burst valve128 can be designed to rupture at a second pressure threshold that is higher than the first pressure threshold at which properly -functioning pressure-release valves 126 vent gas and lower than a pressure that would rupture the container 210.

[0052] There can be a plurality of semiconductor dies 180 mounted on one or more PCBs 160 that are immersed in the coolant liquid 150. There can be one or more types of semiconductor dies, such as but not limited to, a microprocessor (e.g., a central processing unit (CPU) and / or graphic processing unit (GPU)), a digital signal processing (DSP) die, an application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), and / or other densely patterned semiconductor die. One or more semiconductor dies 180 can be mounted in an electronic device package 170 that mounts to the PCB 160. The device package 170 can include a heat-dissipative element thermally coupled to the semiconductor dies 180 to dissipate heat from the semiconductor dies 180 into the coolant liquid 150.Examples of such heat-dissipative elements are described in U.S. provisional application Ser. No. 63 / 489,895 filed on March 13, 2023, titled “Electronic Package Construction for Immersion Cooling of Integrated Circuits,” and in U.S. non-provisional patent application No. 18 / 460,070, filed September 1, 2023, which applications are incorporated herein by reference in their entirety. The heat-dissipative element can thermally couple to the semiconductor die 180 with or without a protective lid over the semiconductor die.

[0053] In the two-phase immersion-cooling system 100, heat flows from the semiconductor dies 180, where the heat is generated during operation of the semiconductor dies, into the heat-dissipative element which is in physical and thermal contact with the coolant liquid 150. The amount of heat delivered to the coolant liquid 150 is enough to boil the coolant liquid. The heating and boiling of the coolant liquid 150 produces the coolant-liquid vapor 140 that rises to the condenser 132. The coolant-liquid vapor 140 can be cooled and condensed back to liquid droplets 142 by the condenser 132. The liquid droplets 142 from the condensed vapor 140 can drip and / or flow back to the coolant liquid 150.

[0054] 1.1 Bellows Assemblies

[0055] FIG. 2A illustrates an example of the bellows assembly 120 in further detail. The bellows assembly 120 can be used with the two-phase immersion-cooling system of FIG. 1. In some implementations, the bellows assembly 120 can be used with single-phase immersion-cooling systems (e.g., when coolant liquids based on fluorochemistry are used as the immersion coolant). A perspective view of the bellows assembly is illustrated with partial transparency to reveal features inside the assembly. The bellows assembly comprisesa container 210 that can be formed, at least in part, from polymer (e.g., polyurethane, mylar, polyethylene, silicone, etc.) The container 210 has an interior surface 215 spanning a surface area that encloses the volume 122 within the container 210. The container can have a rectangular shape, as depicted, or may have another shape (e.g., square, disc, oval, polygonal). At least a portion of the container 210 is reversibly deformable to increase and decrease an amount of the volume 122 enclosed by the container 210 when pressure inside the container changes.

[0056] There can be one or more mounting hardware elements 220 attached to the container 210 to securely mount the bellows assembly 120 in a desired orientation (e.g., vertical as depicted, horizontal, or in any other orientation). A vertical orientation is one in which a deformable wall of the container having a largest area among the container walls (e.g., first wall 211 or second wall 212) is standing on edge, oriented perpendicular to the Earth’s ground or floor on which the immersion-cooling system rests. The mounting hardware elements 220 can be located to reduce their interference with deforming walls of the container 210. For example, the mounting hardware elements 220 can be located at or near corners of the container 210 and / or at or near edges of the container walls 211, 212, 213.

[0057] The illustration of FIG. 2A shows D-rings for the mounting hardware elements 220 that are located at or near eight rounded corners of the container 210. Although FIG. 2A depicts eight mounting hardware elements 220 for the container 210, there can be from one to twenty mounting hardware elements 220 or even more arranged on the container 210 to support the bellows assembly 120. The mounting hardware elements 220 can couple to external structure to stabilize the bellows assembly 120 adjacent to the tank 110 (e.g., over or beside the tank). In some implementations, described further below, there may be no mounting hardware elements 220 attached to or integrally formed with the container 210.

[0058] The mounting hardware elements 220 can be metallic or formed from a polymer. In some implementations, each mounting hardware element 220 can be attached to the container 210 (e.g., with a strap 224, tape, or adhesive). In some cases, each mounting hardware element 220 can attach to a feature on the container, such as a ridge or tab 226 that is integrally formed on an exterior surface of a wall 211, 212, 213 or along edges of the container 210. For example, an O-ring or D-ring 223 can pass through a hole 225 in the ridge or tab 226 that is integrally formed on an exterior surface of a wall 213, as depicted in FIG.2B

[0059] In some implementations, each mounting hardware element 220 can be integrally formed on an exterior wall 213 of the container 210. For example, the mounting hardware element 220 can be an integrally formed ridge or tab 226, as depicted in FIG. 2C, that includes a hole 227 therethrough to allowing mounting of the container (via a screw, bolt, pin or other fastener) to an exterior structure. The hole 227 can be oriented vertically, as depicted in FIG. 2C, or horizontally, as depicted by the hole 225 in FIG. 2B.

[0060] Inside the container 210 can be one or more venting conduits 240 (e.g., tubes) that fluidically couple to the port(s) 124. The venting conduit(s) can allow for ingress and egress of gas into and out of the bellows volume 122. The venting conduits 240 can include one or more vent holes 242 located to avoid being plugged by collapsing walls of the container 210. For example, the vent holes 242 are arranged such that gas exiting the vent holes 242 into the bellows volume 122 flows in a direction that is approximately parallel to (within 20 degrees), or not normal to, at least one deformable wall, such as the first wall 211 (occluded in the drawing) and second wall 212 of the container 210.

[0061] For the implementation of FIG. 2A, each gas port 124 comprises a double flange assembly, which can reduce gas flow impedance and / or provide additional support for the container 210 and / or venting conduits 240 within the container. However, a single flange assembly can be used in some cases, an example of which is described further below in connection with FIG. 3 A.

[0062] The container 210 can include at least the first wall 211, second wall 212, and third wall 213 that enclose at least a portion of the bellows volume 122, as depicted in FIG. 2D. In an ambient environment, when there is no pressure differential across the walls of the container 210, the first wall 211 and second wall 212 can be approximately parallel to each other (z.e., within 20 degrees of being parallel to each other, including being exactly parallel). The first wall 211 can span a first surface area and the second wall 212 can span a second surface area, which may be the same amount as or different amount than the first surface area. The first surface area and the second surface area can form a majority of the interior surface 215 of the container 210 that encloses the volume 122. The first wall 211 can be separated from the second wall 212 by a space occupied by at least a portion of the volume 122. The separation distance d between the first wall 211 and second wall 212 can be from 5 millimeters (mm) to 500 mm, though smaller or larger distances can be used. In some cases, the separation distance d can be from 100 mm to 500 mm. The third wall 213 can connect to the first wall 211 and connect to the second wall 212 and can extend part way or all the wayaround a periphery of the container 210. In FIG. 2 A the third wall 213 extends all the way around the container 210. In other implementations, the container can have six distinct walls (e.g., front, back, top, bottom, left side, right side).

[0063] At least one of the first wall 211, second wall 212, and third wall 213 comprises (or comprise) a flexible polymer that allows the wall(s) to deform when the pressure of gas within the volume 122 changes. The thickness of the flexible polymer can be from 0.1 mm to 3 mm, though thinner or thicker polymer may be used in some cases. In some cases, the thickness of the flexible polymer can be from 0.5 mm to 2.5 mm. The first wall 211 and second wall 212 can have the same rectangular shape, as depicted in FIG. 2A, or may have another shape (e.g., square, disc, oval, polygonal). The first wall 211 and second wall 212 each can span an area (in x and j’ directions in FIG. 2A) from 0.2 square meter (m2) to 3 m2, though larger walls may be used for the container 210. In some cases, the first wall 211 and second wall 212 each can span an area from 0.5 m2to 3 m2. The volume 122 within the container 210 can occupy from 0.05 cubic meter (m3) to 3 m3, though larger volumes may be used in some cases. In some implementations, the volume 122 can occupy from 0.5 m3to 2 m3.

[0064] FIG. 2E and FIG. 2F depict an implementation where the first wall 211 and the second wall 212 comprise a flexible polymer, whereas the third wall 213 is comparatively stiffer. For example, the third wall 213 can be thicker and / or formed from a different material than the thickness of and / or material used to form the first wall 211 and the second wall 212. Under positive pressure (depicted in FIG. 2E), gas within the volume 122 pushes the first wall 211 and second wall 212 outward, away from the center of the container 210 (marked by the x symbol in the drawing). This increases the bellows volume 122 to accommodate more gas from the tank 110. Under negative pressure or vacuum (depicted in FIG. 2F), ambient air outside the volume 122 pushes the first wall 211 and second wall 212 inward, toward the center of the container 210. This decreases the bellows volume 122, returning gas to the tank 110.

[0065] Although FIG. 2E and FIG. 2F depict an implementation where two walls comprise flexible polymer and can deform, in another implementation only one wall (e.g., the first wall 211) can comprise a flexible polymer and deform according to changes in pressure of the gas within the bellows volume 122. In such implementations, at least one of the walls 211, 212, 213 can differ from at least one other wall of the container 210. For example, one or more walls 211, 212, 213 may differ in material composition and / or thickness such that one wall iscomparatively stiff, and flexes insignificantly compared to another wall of the container 210. When the container 210 includes a stiff wall or walls, the gas ports 124, pressure-release valve 126, and / or mounting hardware elements 220 can be attached to the stiff wall or walls. Further, a heating element and / or insulating enclosure (described in more detail below) can be attached to and / or supported by the stiff wall or walls. In another implementation, the first wall 211, second wall 212, and third wall 213 can all comprise a flexible polymer and deform according to changes in pressure of the gas within the bellows volume 122.

[0066] FIG. 2G depicts another implementation of the bellows assembly 120. This implementation of the bellows assembly includes the burst valve 128 and a drain port 252. The bellows container 210 further includes a protrusion 250, though the protrusion 250 is not necessary and can be omitted from the base of the container 210. The protrusion can extend from the base of the container a distance D that is from 1 cm to 10 cm. The burst valve 128 is oval shaped, but can be any other shape (e.g., round, square, rectangular, polygonal, etc.). The drain port 252 is located at a base of the bellows container 210 such that it can provide for drainage of condensation that collects at the base of the container 210 when the immersion-cooling system 100 is in operation.

[0067] The bellows volume 122 for the implementations of FIG. 2A and FIG. 2G can be a sizable fraction of the volume of the tank’s headspace 114. Because the semiconductor dies 180 in the tank 110 can operate at very different workloads, the amount of coolant-liquid vapor 140 in the bellows and its temperature can vary significantly, thereby changing the pressure and volume of gas entering and exiting the bellows container 210. To accommodate such dynamic variations in volume, the bellows volume 122 can be from 40% to 150% of the volume of headspace 114 in the tank, when the tank contains coolant liquid and the immersion-cooling system is operating.

[0068] When the immersion-cooling system 100 is in operation, coolant-liquid vapor 140 that enters into the bellows assembly 120 can condense on walls of the bellows container 210, for example, collect at the base of the container 210, and would otherwise run back through the port(s) 124 into the tank 110 if not drained by the drain port 252. With the drain port 252, contaminated condensate can be collected, filtered, and recovered for use again in the system’s tank 110.

[0069] Although the drain port 252 is depicted at the base of the protrusion 250 in FIG. 2G, in some cases the container 210 may not contain the protrusion 250 and the drain port 252 could be located at a lowest or near-lowest point in the container 210 (e.g., within 5 cm of thelowest point in the container 210 where liquid will collect when the container 210 is in use). If the protrusion 250 is not present, the drain port 252 could be located anywhere along the bottom wall 213 of the container or near the bottom wall 213 (e.g., in a low region of the first wall 211 or second wall 212). In some cases, a drain port 252 can be located in the flange assembly of the gas port 124 that couples the bellows container 210 to the tank’s headspace 114 (e.g., in a flange 312 of the gas port 124, referring to FIG. 3A through FIG. 3E). Locating the drain port 252 in the flange of a gas port 124 can avoid additional hardware (flanges and gaskets) for an additional entry port into the container 210.

[0070] As illustrated in FIG. 2 A, the port(s) 124 can include venting conduits 240 that extend up into the container 210. The venting conduits 240 can prevent, to some extent, condensate from the lowest region of the container 210 running back through the port(s) 124. The venting conduits 240 can allow condensate to collect and reach a depth in the container 210 (e.g, up to the first vent hole 242). Thus, the drain port 252 can be located anywhere in the container 210 below the first vent hole 242 in the venting conduits 240.

[0071] Because the container 210 for the bellows assembly 120 of FIG. 2A and FIG. 2G can contain contaminants as well as water vapor during operation, it can be desirable to filter the condensate before returning the condensate to the tank 110. A filter 260 can be fluidically coupled to each drain port 252, as shown in FIG. 2G. Gravity filtering (using gravitational force) and / or pressure filtering (using an applied pressure) can be implemented for the condensate flowing out of the drain port 252. Filtering of the condensate before returning it to the tank 110 can prolong the service life of coolant liquid 150 in the tank. The filter 260 can include one or more filtering sections that perform the same or different types of filtering actions. One or more of the filtering sections (which may be separate filters) can perform sieve-type filtering to capture particulates (e.g, passing the condensate through a porous material), activated filtering to chemically bind with and capture certain chemical contaminants in the condensate (e.g., passing the condensate through an activated substance such as activated charcoal), hygroscopic filtering to remove water from the condensate (e.g., passing the condensate through or over a hygroscopic substance such as activated alumina that binds water), or some combination of these filtering actions. The filtering sections (when multiple sections are used) can be arranged in any order. For example, a sieve-type filtering section can be arranged first to remove particles from the condensate that would otherwise clog an activated filtering section that follows the sieve-type filtering section.

[0072] According to some implementations, the bellows assembly 120 is mounted with the mounting hardware elements 220 such that the container 210 is in a vertical orientation, as depicted in FIG. 1 and FIG. 2A. In a vertical orientation, the wall(s) 211, 212 of the container 210 that undergo the most deformation due to changes in pressure of gas within the bellows volume 122 can move horizontally and without hindrance by any external structure. The horizontal direction would be parallel to a floor on which the immersion-cooling system 100 rests. In such an orientation, two or more bellows assemblies 120 could be mounted end- to-end, side-by-side (with appropriate spacing therebetween), and / or above and below each other to service one tank 110.

[0073] Other mounting orientations are possible, including horizontal. The container 210 may be mounted horizontally using the same or different mounting hardware elements. In a horizontal orientation, the wall(s) 211, 212 of the container 210 that undergo the most deformation due to changes in pressure of gas within the bellows volume 122 can move vertically and without hindrance by any external structure. In a horizontal orientation, two or more bellows assemblies 120 could be mounted above and below each other to service one tank 110.

[0074] Referring again to FIG. 1, changes in pressure of gas within the bellows volume 122 can be caused by changes in operation of the semiconductor dies 180 within the tank 110 of the immersion-cooling system 100. For example, when all semiconductor dies 180 in the tank 110 are operating at full capacity, they will generate a significant amount of heat that causes the most amount of boiling of the coolant liquid 150. This boiling at peak operation produces the most amount of coolant-liquid vapor 140 from the coolant liquid 150 that goes into the headspace 114, heating air in the headspace and increasing pressure in the headspace. The increased pressure of the gas within the headspace 114 forces gas from the headspace 114 into the bellows volume 122 via at least one gas port 124 and expands the container 210, as depicted in FIG. 2E. If an over-pressure event occurs during peak operation, gas can be vented from the system (as described further below). When operation of the semiconductor dies 180 decreases such that only one or a few semiconductor dies are operating at low capacity, the coolant liquid 150 can cool and the amount of coolant-liquid vapor 140 in the headspace 114 can decrease, creating a comparative vacuum or negative pressure condition in the headspace 114 with respect to the bellows volume 122. This negative pressure condition in the headspace 114 allows the container 210 to expel gas from the bellows volume 122, through the port(s) 124, and back into the headspace 114. In some cases, the negativepressure in the headspace can pull gas from the bellows volume 122, causing the container to deform inward as depicted in FIG. 2F.

[0075] When gas pressure within the headspace 114 and / or bellows volume 122 exceeds a predetermined pressure threshold, it can be vented through one or more pressure-release valves 126. High pressure within the headspace 114 can be undesirable because it can change the boiling temperature of the coolant liquid 150. Accordingly, the pressure threshold for release of gas may be a small amount above the ambient pressure (e.g., from 0.2 psi to 3 psi above the ambient pressure around the immersion-cooling system 100), though a higher pressure-release threshold can be used in some implementations. When pressure exceeds the pressure threshold value, the pressure-release valve(s) 126 can open to release gas from the system. According to some implementations, the container 210 is configured to controllably rupture (rather than explode) at a second pressure threshold that is higher than the pressurerelease threshold. For example, a seam or groove formed in the container 210 can be configured to tear at a second pressure threshold that is from 2 psi to 10 psi higher than the pressure release threshold. The controlled rupture can occur if the pressure-release valve(s) stick(s), for example.

[0076] The inventors have recognized and appreciated that some coolant liquids 150 are expensive and that venting coolant-liquid vapor 140 into an ambient environment can incur a significant operating expense for the immersion-cooling system 100. Accordingly, the pressure-release valve(s) 126 can be located in the system 100 to reduce an amount of coolant-liquid vapor 140 released during an over-pressure event. Since the coolant-liquid vapor 140 can be heavier than air and heavier than water vapor, the pressure-release valve 126 can be located at a high elevation in the immersion-cooling system 100. At a higher elevation, the partial pressure and content of coolant-liquid vapor 140 can be lower than the partial pressure and content of the coolant-liquid vapor 140 at a lower elevation, near the coolant liquid 150, in the system. For example, the coolant-liquid vapor 140 can be comparatively denser than air so that the air molecules (oxygen, nitrogen) in the tank 110 are relatively lighter. The difference in densities between air and coolant-liquid vapor 140 will cause the air molecules to rise upwards and the coolant-liquid vapor 140 to stay relatively lower. Therefore, when the air is pushed upwards by the coolant-liquid vapor 140 from the coolant liquid 150 in the tank 110, air will move up from the headspace 114 in the tank 110 to the container 210. Instead of mounting a pressure-release valve(s) 126 directly to the tank 110, the pressure-release valve(s) 126 can be located above the tank 110 (e.g., on anextension pipe the extends vertically above the tank and / or bellows assembly 120, or high on the container 210 of the bellows assembly 120).

[0077] For implementations like that depicted in FIG. 1, the bellows assembly 120 is located vertically above the tank 110 and the pressure-release valve(s) 126 can be located at or near a top edge of the container 210. For example, the pressure-release valve(s) 126 can be located within 10 centimeters (cm) of an edge 219 of a wall of the container 210, or even withing 5 cm of an edge 219 of a wall of the container 210, where the edge is a top edge of the container 210 when the bellows assembly 120 is mounted to service the tank 110 during operation of the immersion-cooling system 100. In some implementations, the pressurerelease valve(s) 126 can be located on a top, upward facing wall of the container 210. When a pressure-release valve 126 mounted high in the system opens during an over-pressure event, it can vent proportionately more air and / or water vapor and less coolant-liquid vapor 140 from the system than the valve would vent if located at a lower elevation in the system (e.g., in the tank 110 closer to the coolant liquid 150 or near the bottom of the bellows assembly 120). For example, the gas near the top of the container 210 can contain a lower percentage or concentration of coolant-liquid vapor 140 than gas near the bottom of the container 210.

[0078] The bellows assembly 120 can include one or more gas ports 124 to admit gas into the bellows volume 122 from the headspace 114 in the tank 110 and to expel gas from the bellows volume 122 back to the headspace 114. The port(s) can include hardware elements that attach to the container 210 of the bellows assembly 120. A gas port 124 may also be used to attach each pressure-release valve 126 and or a sensor to the container 210.

[0079] FIG. 3A depicts, in cross-section and partial exploded view, one example of a gas port 124 that can attach to the container 210. The gas port 124 can include a port insert 310 that includes a flange 312 having a plurality of flange holes 314 through the flange 312. The flange holes 314 can be distributed around the flange 312. The port insert 310 can include at least one exterior conduit 315 that fluidically couples to at least one interior conduit 317. The interior conduit 317 can be arranged to pass through the container wall 213 and extend into the interior of the container 210 when the port insert 310 is mounted to a wall (e.g., the third wall 213) of the container 210. In some cases, the interior conduit 317 fluidically couples to the venting conduit 240 or is configured to be the venting conduit 240 (e.g., by having at least one hole to vent gas as described above for the venting conduit 240 of FIG. 2A. In some implementations, the flange 312 can be welded or otherwise adhered to a conduit to make the port insert 310. One or both of the interior conduit 317 and exterior conduit 315 can have asmooth outer surface (as shown) or may have a barbed outer surface for attaching a flexible hose or a tube.

[0080] A region of the container wall 213 where the gas port 124 mounts can include an entry hole 302 to receive the port insert 310 and may or may not include a ring 306 of increased wall thickness surrounding the entry hole 302. There can be a plurality of container screw holes 304 in the container wall 213 surrounding the entry hole 302 and having a pattern that matches the pattern of the plurality of flange holes 314 in the flange 312. Threaded rivet inserts 330 can be placed in the screw holes 304 through the container wall 213 and tightened to engage the riveting action and provide threaded nuts secured to the container 210.

[0081] To seal the port insert 310, exterior conduit 315, and interior conduit 317 to the container 210, a gasket 320 can be located between the flange 312 and the container wall 213. In some cases, the gasket 320 can be formed from a soft material (e.g., silicone or a closedcell foam). Additionally, or alternatively, the gasket 320 can be formed in place (e.g., by applying silicone or another sealant on the flange 312 and / or container wall 213 where the flange 312 mates to the wall 213). The gasket 320 can include a plurality of holes 322 that align with screw holes 304 in the container and with the plurality of flange holes 314. Machine screws (not shown) can then be inserted through the flange holes 314, through the gasket 320, and into the threaded rivet inserts 330. The machine screws can be tightened to seal the port insert 310 to the container. Flexible washers 340 may or may not be used as an additional seal around each flange hole 314 (c.g, to prevent gas from escaping through the threads of the machine screws).

[0082] Once sealed to the container 210, a conduit (e.g., a tube or hose) can be attached to the exterior conduit 315 of the port insert 310. The conduit can also connect at a distal end to a gas port 124 on the tank 110 to fluidically couple the volume 122 of the container 210 to the headspace 114 in the tank 110. In some cases, a flexible hose can slide over the exterior conduit 315 and be secured with a hose clamp. In some cases, the exterior conduit 315 can include hose barbs and a flexible hose can be pushed over the barbs to secure the hose. In some implementations, a tube having an inner diameter large enough to slide over the exterior conduit 315 (or outer diameter small enough to fit inside the exterior conduit 315) can be adhered to the exterior conduit 315 with an adhesive and / or crimped onto the exterior conduit.

[0083] FIG. 3B depicts another implementation of a port insert 311 that may be used alternatively in the port assembly of FIG. 3A. In this implementation, the port insert 311includes a first flange 312 and a second flange 313. Both flanges can include a plurality of flange holes, which may be arranged in the same or different patterns around the exterior conduit 315. The first flange 312 can be used to attach the port insert 310 to the container 210 of a bellows assembly 120. The second flange 313 can attach with machine screws and a gasket to a mating flange on the tank 110 of the immersion-cooling system 100, for example.

[0084] Because the port inserts 310, 311 can be made from a rigid material (e.g., a metal or stiff polymer), they can provide mechanical support to the container 210 of the bellows assembly 120. For example, one or more port inserts 310, 311 can rigidly couple to the tank 110 via the second flange 313 and / or exterior conduit 315 and provide adequate support for the container 210 and bellows assembly 120, as depicted in FIG. 6B. In such implementations, mounting hardware elements 220 may not be included on the container 210.

[0085] FIG. 3C depicts another implementation of a gas port 124. In this implementation, an exterior port insert 311a and an interior port insert 311b are located outside and inside the container 210, respectively. The exterior port insert 311a comprises an exterior conduit 315 connected to a first flange 312. The interior port insert 311b comprises an interior conduit 317 connected to a second flange 316. Each flange can connect to its conduit by welding or an adhesive. The first flange 312 can include a first plurality of holes 314 and the second flange 316 can include a second plurality of holes 327 that align to each other. Threaded blind inserts 331 can be placed in the second plurality of holes 327, or the holes 327 themselves can be threaded and the blind inserts not used. Two gaskets 320, 321 with aligned holes 322, 323 can be placed on either side of the container wall 213 to seal the port inserts 31 la, 31 lb to the container wall 213. To get the interior port insert 311b inside the container, the entry hole 302 in the container wall 213 and the flanges 316, 312 can be oval or oblong. Machine screws or bolts can be placed through the holes to engage threads in the blind inserts 331 to clamp the assembly together.

[0086] FIG. 3D depicts another implementation of an exterior port insert 311a that can be used in the port assembly of FIG. 3C. The exterior port insert 311a includes a second flange 313 to provide for coupling to another flange or device. For example, the second flange 313 could couple to a flange on the tank 110 of the immersion-cooling system 100.

[0087] FIG. 3E is an illustration of one example of a gas port 124 that could be used with the container 210. The gas port 124 includes an additional exterior conduit 315a that is connected to the flange 312. In some implementations, the second flange 313a of the exterior conduit(s) may not contain holes and may be quick-release type flanges, for example.

[0088] The gas port 124 can also be used to fluidically couple the pressure-release valve 126 to the container 210 of the bellows assembly 120. For example, the pressure-release valve 126 can couple to or directly mount onto the exterior conduit 315 of the port insert 310 of FIG. 3 A, or the pressure-release valve 126 can couple to or directly mount onto the second flange 313 of the port insert in FIG. 3B or FIG. 3D. The pressure-release valve 126 can also couple to the exterior port insert 311a of FIG. 3C.

[0089] FIG. 3F depicts, in exploded view, one example of a burst valve 128 that can be used with the containers 210 of FIG. 2A and FIG. 2G. The burst valve 128 can comprise a first flange ring 361 that surrounds an entry hole 302 in a wall 212 of the container 210. The first flange ring 361 can have a plurality of holes 314 for screws to pass through. The first flange ring 361 can be formed from a metal or rigid polymer. A second flange ring 362 can be located inside the container 210 and comprise a plurality of threaded blind inserts 331 that align with the plurality of holes 314 in the first flange ring 361. A screw passing through a hole 314 in the first flange ring 361 can pass through a screw hole 304 in the container and can thread into the mating blind insert 331 in the second flange ring 362. In other implementations, the second flange ring 362 comprises threaded holes or threaded inserts instead of threaded blind inserts 331.

[0090] The burst valve 128 can further comprise two gaskets 320, 321 to form air-tight seals with the container’s wall 212. The two gaskets 320, 321 with gasket holes 322, 323 aligned to the plurality of holes 314, 327 in the first flange ring 361 and second flange ring 362 can be placed on either side of the container wall 212 to form the air-tight seal.

[0091] The burst valve 128 can further comprise a membrane 370 sandwiched between the two gaskets 320, 321. The membrane 370 can be located on either side of the container wall 212. In some implementations, one or both of the gaskets 320, 321 may not be used and the membrane 370 is sandwiched between the first flange ring 361 and second flange ring 362, and may be located on either side of the container wall 212. In such implementations, the membrane 370 can form a sufficient air-tight seal with the container wall 212.

[0092] The membrane 370 can be formed from a polymer and can be designed to rupture at a pressure that is lower than a pressure that would rupture the container 210 should the pressure-release valve(s) 126 fail. For example, the membrane material can be made of a same polymeric material as the container 210 but have a thickness that is less than the smallest thickness of the container material. In some implementations, the membrane material can be made of a different material that has a lower rupture strength than the rupturestrength of the material used to make the container 210. The thickness of the membrane 370 can be less than the thickness of the container wall 212, equal to, or greater than the thickness of the container wall 212, depending on the material used for the membrane 370 and its structure.

[0093] In some cases, the membrane 370 can be structured to include a weak spot in the membrane that will burst at a desired pressure. For example, a kerf can be cut, molded into, or otherwise formed in the membrane 370 creating a weak region of the membrane that will burst and / or tear open at a desired pressure.

[0094] The burst valve 128 can be located in any wall of the container 210 or at other locations in the system that are fluidically coupled to the volume 122 within the container 210. In some implementations, the burst valve can be included in a gas port 124 into the container. For example, the burst valve 128 can be located in a port’s flange assembly, such as the flange assembly of FIG. 3C. The sizes of the port’s first flange 312 and the second flange 316 can be extended to provide a region for the burst valve 128 (e.g., to one side of the interior conduit 317). The same flange assembly might also accommodate the drain port 252, which could avoid additional hardware (flanges and gaskets) at an additional entry hole 302 into the container 210 for the burst valve 128 and the drain port 252.

[0095] FIG. 3G depicts a single flange assembly 380 that comprises a gas port 124 to fluidically couple the bellows volume 122 to the headspace 114 in the tank 110. The flange assembly 380 further comprises a drain port 252 and a burst valve 128. The burst valve’s membrane 370 is disposed at a first location in the flange assembly 380 (to a first side of the interior conduit 317). The drain port 252 is located on an opposite side of the interior conduit 317. The drain port can comprise a drain conduit 254 for removing fluid from the interior of the container 210. An external conduit, such as a tube or pipe, can fluidically couple the drain conduit 254 to the filter 260. Filtered condensate flowing out of the filter 260 may or may not be collected before returning to the tank 110.

[0096] The drain conduit 254 can protrude from a flange 312 of the flange assembly 380 (e.g., from the external flange piece). Either of the flange assemblies of FIG. 3A and FIG. 3B can also be adapted to include one or both of the burst valve 128 and drain port 252. The drain port 252 can be located toward the bottom center of the container 210 or toward the bottom comer of the container 210.

[0097] To reduce the amount of condensate that accumulates in the bellows container 210, the flange 316 and gasket 321 inside the container 210 can each have a cut-out 319, also shown in the plan view of FIG. 3H, which depicts a portion of the flange 316 at the location of the drain port 252. The cut-outs 319 allow fluid at the bottom of the container to reach the drain conduit 254 without pooling to a depth needed for fluid to flow over the top of the gasket 321 and the flange 316. However, without the cut-outs 319, condensate can pool and drain from the drain conduit 254 without leaking from the bellows container 210 elsewhere. The blind inserts 331, which can be sealed to the flange 316, can prevent leakage around screws that hold the flange assembly 380 together. The interior conduit 317 can prevent leakage of condensate back through the gas port 124 and into the tank 110.

[0098] According to some implementations, to reduce contamination of the condensate from metal of the flange assembly 380 of FIG. 3G (and from other flange assemblies described herein), at least the portions of the flange assembly exposed to condensate within the container 210 can be coated with a polymer or other coating that is not dissolvable by the coolant liquid 150. Polymers that may be used as a coating include polyurethane, mylar, polyethylene, silicone, etc.

[0099] In some implementations, at least one vapor barrier can be used in the immersioncooling system 100 to block the flow of the coolant-liquid vapor 140 and / or water vapor from reaching some parts of the system, such as the bellows assembly 120 and / or to an exhaust port of the pressure-release valve 126. FIG. 3A depicts one implementation of a vapor barrier 350 that can be mounted in a port insert 310 of a gas port 124. The vapor barrier 350 can comprise a membrane with micrometer-scale or nanometer-scale holes that are sized to block the flow of coolant-liquid vapor 140 and / or water vapor past the vapor barrier 350, and yet allow the flow of air molecules (e.g., oxygen and nitrogen gases) to pass through the vapor barrier. In some implementations, the vapor barrier can comprise an activated filter to capture coolant-liquid vapor 140 and / or water vapor.

[0100] One or more different or same vapor barriers 350, or a mixture of same and different vapor barriers, can be used in the immersion-cooling system 100. For example, a first vapor barrier 350 can be used to block the passage of coolant-liquid vapor 140 into the bellows volume 122 and / or to block the flow of coolant-liquid vapor 140 into a pressure-release valve 126. A second vapor barrier may be located to capture water vapor passing between the headspace 114 and the bellows volume 122. The vapor barrier(s) 350 (which can comprise a molecular sieve, desiccant, adsorbent, or some combination thereof) can be located in one ormore places within the immersion-cooling system 100 (e.g., at gas ports 124 on the tank 110, at gas ports 124 of the bellows assembly 120 including those used to mount one or more pressure-release valves 126, and within the container 210 (e.g., partitioning the bellows volume 122 into two regions where one region contains the pressure-release valve(s) 126. The vapor barrier(s) 350 can be located to block coolant-liquid vapor 140 from entering the region contains the pressure-release valve(s) 126.

[0101] 1.2 Heating the Bellows

[0102] The inventors have further recognized and appreciated that condensing of coolantliquid vapor 140 and water vapor in the bellows assembly 120 can be undesirable. For example, the coolant liquid 150 may contain a fluoroketone that can react with liquid water and create an acid. The acid may be corrosive to some components in the system. By blocking the flow of water vapor that would otherwise flow back into the tank 110 from the bellows volume 122 and / or capturing water vapor (e.g., with a desiccant in the vapor barrier 350), the creation of acid in the tank can be prevented.

[0103] Condensation of water vapor and / or coolant-liquid vapor 140 in the bellows assembly 120 can be prevented by heating the bellows assembly and / or providing heat to the gas within the container 210. One approach to providing heat to the gas within the container 210 is depicted in FIG. 1. A heater 190 comprising a heating coil 192 can carry a heat-transfer liquid (e.g., water or a mixture comprising ethylene glycol) to heat gas within the bellows volume 122. The heating coil 192 can be inside the container 210 of the bellows assembly 120 (e.g., directly heating gas within the bellows volume 122) or can be external to the container 210 (e.g., heating walls of the container 210). The heating coil 192 can be part of a closed-loop fluid circuit 195 that extends into the coolant liquid 150 within the tank 110 where heat is coupled to the heat-transfer liquid by a coil 197 immersed in the coolant liquid 150. There can be one or more fluid circuits 195 providing heat to one or more bellows assemblies 120 in an immersion-cooling system 100. Gas ports 124 like those described above in connection with FIG. 3A and FIG. 3B can be used to pass the fluid conduit of the fluid circuit 195 through walls of the container 210 and through walls of the tank 110. The heater 190 can be passive in some cases (e.g., relying on thermally-induced flow of the heattransfer liquid in the system) or can be active (e.g., mechanical pumping of the heat-transfer liquid and / or heated by an external active heat source instead of entering the tank 110 and being heated by the coolant liquid 150). In some cases, the heat-transfer liquid can be aphase change material (PCM) that changes into a vapor phase when heated in the tank 110 by the coolant liquid 150 or when heated by an external source.

[0104] Other types of heaters 190 can be used for the bellows assembly 120. FIG. 4A depicts an implementation where an electrically-resistive heating element 410 is thermally coupled to a wall 212 of the container 210. The heating element 410 can be a flexible heating pad, resistive wire, silicone heater, a heating element embedded in rubber or fiberglass, an etched foil flexible heater, polyimide heater, heating tape, Peltier, or thermoelectric heater. In some cases, the heating element 410 (such as a silicone heater) can form at least a portion of a wall of the container 210.

[0105] FIG. 4B depicts another heating arrangement where the electrically-resistive heating element 410 enters into the bellows volume 122 to heat gas directly inside the container 210. The heating element 410 may connect to a port insert 310 of a gas port 124 described above in connection with FIG. 3A and FIG. 3B.

[0106] Another method of providing heat to the bellows assembly 120 can be similar to that shown in FIG. 1 except that the heat for the fluid circuit 195 is provided by another source instead of the coolant liquid 150. In one example, the fluid circuit 195 can be an extension of the fluid circuit 135 connected to the chiller 130. The return line from the condenser 132 can be extended to run to a heating coil 192 in the bellows assembly 120 before returning to the chiller 130, as depicted by the fluidic circuit extension 137 in FIG. 1 (dashed, shaded lines). Heat received from condensing coolant-liquid vapor 140 in the tank 110 can be provided to the bellows assembly 120. In another example, the fluid circuit 195 can run to the chiller 130 instead of the tank 110 and receive heat from the chiller 130 that is generated in the process of cooling liquid coolant circulated through the condenser 132.

[0107] In some implementations, a heater 190 can provide heat to an enclosure surrounding the bellows assembly 120, such as the insulated enclosure 510 depicted in FIG. 5A. The inventors have recognized and appreciated that some operating environments, such as those at data centers, can be cool and may cause condensing of water vapor and / or coolant-liquid vapor 140 in the bellows assembly 120. Accordingly, an insulated enclosure 510 can be placed around the bellows assembly, as illustrated in FIG. 5A. The insulated enclosure 510 can comprise an insulation 512 that lines most of the enclosure 510. The insulation 512 can comprise a foam, a fiberglass insulation, and / or a heat reflecting barrier that is arranged to reflect heat back inside the insulated enclosure 510. Insulating foam can be flexible (e.g., Armaflex® foam sheet insulation) or can comprise an expanded polystyrene such asStyrofoam®. In some cases, the enclosure 510 can further include a shell 520 surrounding the insulation 512. The shell 520 can form an outer protective surface and can be made from a different material than the insulation 512 (e.g., a metal, polymer, or composite material such as fiberglass). In some implementations, the insulation 512 can be external to the shell 520. When an insulated enclosure 510 is used, the heating element 410 can be mounted to the bellows assembly 120 (as depicted in FIG. 5A), between the bellows assembly 120 and the insulated enclosure 510, or can be mounted to the insulated enclosure 510 (as depicted in FIG. 5B) In some implementations, the insulated enclosure 510 is sized to avoid interfering with motion of the deformable wall(s) 211, 212, 213 of the container 210 when the container expands and contracts.

[0108] The insulated enclosure 510 can be mounted on top of the tank 110, in some implementations. In such cases, heat from the tank that is captured by the insulated enclosure 510 may be sufficient to heat the bellows assembly 120 and prevent condensing of water vapor and / or coolant-liquid vapor 140 in the container 210. In such cases, a heater 190 and heating element 410 may not be included.

[0109] In some implementations, the container 210 can be insulated with a flexible insulation layer applied to at least some of the walls of the container. FIG. 5C depicts such an implementation where flexible insulation 512 is applied to at least portions of at least three walls of the container 210. In some cases, the insulated enclosure 510 comprises an insulative blanket that fits over the bellows assembly 120. In an additional example, the flexible insulation 512 can be a sheet of insulation that is adhered to one or more walls of the container 210. In a further implementation, the insulation 512 can be sprayed onto and adhered to the walls of the container 210. In yet an additional example, the insulated enclosure 510 can be constructed to behave like a bellows and may or may not use an inflatable container 210 inside the enclosure 510. In such an example, the insulated enclosure 510 can have gas ports 124 and the pressure-release valve(s) 126 mounted directly on the enclosure 510.

[0110] Another approach to heating the gas within the bellows volume 122 is to thermally couple at least a portion of one wall of the container 210 to a wall of the tank 110, as depicted in FIG. 5D. The wall 212 of the container 210 that thermally couples to the wall of the tank 110 may comprise a metal or other thermally conductive material. In some cases, a thermally-conductive adhesive or paste can be used to improve heat transfer from the tank 110 to the container 210. An insulation 512 can surround at least a portion of the container210. One or more gas ports 124 can couple the headspace 114 in the tank 110 to the bellows volume 122. The port(s) 124 can be located on a side of the container 210 (as illustrated in the arrangement on the left side of FIG. 5D) or can be located on a bottom wall 213 of the container and connect to another port through the side wall of the tank 110 (as illustrated in the arrangement on the right side of FIG. 5D). One or more isolation valves 125 can be used in the arrangement of FIG. 5D (e.g., included within a gas port 124 or located between a gas port 124 on the bottom wall 213 of the container 210 and the side wall of the tank 110).

[0111] According to some implementations, one or more walls 211, 212, 213 of the container 210 can be made from an insulative material, such as a closed-cell, flexible foam insulation that is impervious to gas flow. The gas ports 124 and the pressure-release valve(s) 126 can be mounted directly on the insulative walls of the container 210. There may or may not be additional insulation around the container 210.

[0112] 1.3 Mounting the Bellows

[0113] FIG. 6A depicts an example of support structure 600 that can be used to suspend or support one or more bellows assemblies 120 above a tank 110. Such a support structure can be used, for example, when flexible tubing is used to fluidically couple the container 210 to the tank 110 via gas ports 124. The support structure 600 comprises vertical risers 610 that include mounting hardware elements 620 (e.g., tabs, pins, holes, etc.) to couple to mounting hardware elements 220 on the container 210. In some implementations, horizontal struts having mounting hardware elements 620 could be used instead of the vertical risers 610 to engage with mounting hardware elements 220 on the container. There can be as few as one vertical riser 610 (or horizontal strut) at opposing ends or sides of the bellows assembly 120 to support the bellows assembly, though more vertical risers 610 and / or horizontal struts can be used. The support structure 600 may or may not be part of a framework that can be suspended from above (e.g., attached to overhead rails or other structure) or supported from below (e.g., mounted to the top of the tank 110 and / or to the floor on which the immersioncooling system rests). In some cases, the support structure 600 can be supported from lateral structure (e.g., by walls or posts rising adjacent to the tank 110).

[0114] According to some implementations, the support structure 600 can include one or more horizontal supports 612 (e.g., rod(s) or bar(s)) that can be supported at each end by the vertical risers 610. The bellows container 210 can additionally, or alternatively, include a plurality of mounting hardware elements 220, as described above, distributed along the top of the container 210. The container 210 can additionally, or alternatively, be supported alongthe top as indicated in FIG. 6A. Supporting the container 210 at multiple locations along the top can significantly reduce or prevent droop and / or collapse of the container when pressure is released from the volume 122 of the container 210. For example, when pressure is released from the volume 122 during operation of the immersion-cooling system, the top center of the container 210 may collapse toward the bottom of the container, potentially causing an undesirable release of coolant-liquid vapor 140 into the ambient environment as described further below in connection with FIG. 7.

[0115] FIG. 6B depicts an example where the bellows assembly 120 is supported by one or more stiff conduits 630 (e.g., stiff tubes) that fluidically couple the bellows assembly to the tank 110. The conduit(s) 630 can connect to gas ports 124 on the bellows assembly 120 and tank 110. In such cases, no other support structure may be needed to support the bellows assembly. The stiff conduits 630 can comprise a metal and / or polymer and be of sufficient strength to support the bellows assembly 120 without collapsing.

[0116] FIG. 7 depicts another arrangement for mounting the bellows in an immersioncooling system 100, a portion of which is shown. The reference numbers refer to the same components present in previous drawings and described above and need not be described again. In some implementations, the bellows container 210 can be located adjacent to a side of the tank 110. There can be one or more bellows fluidically coupled to the headspace 114 in the tank and mounted adjacent to the tank 110 (e.g., mounted beside two sides of the tank 110 as shown in FIG. 7). In some cases, the bellows container 210 can hang from the conduit 705 that fluidically couples the inner volume 122 of the container 210 to the headspace 114 in the tank 110. For example, the conduit 705 can comprise a metal and / or polymer and be part of a metal and / or polymer conduit assembly 708 that fluidically couples the bellows volume 122 to the headspace 114. The conduit 705 and / or conduit assembly 708 can be strong enough to support the weight of the bellows container 210 and its ports. In such an arrangement, the gas port 124 that fluidically couples the container 210 to the tank’s headspace 114 can be located at or near the top of the bellows container 210 (e.g., within 20 cm of the top of the container).

[0117] Condensate from the bellows can be filtered and collected in a sump 710 that fluidically couples to the drain port 252. In some implementations, the filtering can be done after collection of condensate in the sump 710. A pump 720 can be used to pump the condensate back to the tank 110 through a conduit 730, such as a pipe or flexible tubing. Insome cases, the pump 720 may force condensate drained from the container through one or more filters before returning filtered condensate to the tank.

[0118] The burst valve 128 can be located along the conduit assembly 708, either on the tank side of the isolation valve 125 as shown in FIG. 7 or on the bellows side of the isolation valve. Locating the burst valve 128 along the conduit assembly 708 can avoid adding an entry hole in a wall of the bellows container 210 for the burst valve. Additionally, the burst valve 128 may be easier to service and replace when mounted to the rigid conduit assembly 708. Because the coolant-liquid vapor 140 is typically heavier than air, locating the burst valve 128 at or near the top of the system can significantly reduce the amount of coolantliquid vapor 140 that is lost into the ambient environment when the membrane 370 of the burst valve 128 ruptures. For example, the burst valve 128 can be located within the top quarter of the volume comprising the bellows volume 122 and the volume of the headspace 114.

[0119] In some implementations, having an upper portion of the bellows container 210 supported (as indicated in FIG. 7 and FIG. 6A) can avoid collapse of the container 210 when pressure is release from the headspace 114 and bellows volume 122. For example, the inventors have recognized and appreciated that if the bellows container 210 is formed from a thin, highly flexible material, is mounted in the arrangement of FIG. 6B, and is not self- supporting, then opening an access door to the tank 110 can reduce pressure in the tank’s headspace 114 and in the bellows volume 122 to an extent that the container 210 may collapse upon itself and undesirably force more coolant-liquid vapor 140 out of the headspace 114 and into the ambient environment. Such collapse can be avoided by attaching supporting structure to an upper portion (e.g., the upper quarter) of the container 210 (as indicated in FIG. 6 A and FIG. 7). Such support can prevent the top of the container 210 from fully collapsing onto the bottom of the container.

[0120] Another way to prevent collapse of the container 210 upon pressure release from the tank 110 is with the isolation valve 125, as described above. The isolation valve(s) 125, which can be closed prior to opening an access door to the tank 110, can prevent the backflow of gas and coolant-liquid vapor 140 into the tank 110 and out the open access door. By closing the isolation valve(s) 125 prior to opening the tank’s access door, pressure can be maintained within the bellows volume 122, preventing the bellows container 210 from collapsing on itself.

[0121] In some implementations, a pressure sensor 760 can be disposed in the tank 110 to sense the pressure in the headspace 114. The pressure sensor 760 can be monitored by the controller 118 (referring to FIG. 1). A detected sudden decrease in pressure and / or prolonged decrease in pressure (due to rupture of the burst valve 128, for example) can cause the controller 118 to close the isolation valve(s) 125, which can prevent loss of coolant-liquid vapor 140 from the bellows container 210. Detecting the sudden decrease in pressure and / or prolonged reduction in pressure can comprise the controller 118 detecting a rate of reduction in the sensed pressure that exceeds a threshold rate of reduction and / or that extends for a prolonged period of time. Closing the isolation valve(s) in response to detecting a sudden decrease in pressure in the tank’s headspace 114 can further reduce the loss of coolant-liquid vapor 140 into the ambient environment.

[0122] 2. Management of Coolant Vapor in the Immersion Tank

[0123] The inventors have further recognized and appreciated that immersion-cooling systems can be adapted to include a dehumidifier and a gas management system to manage coolant vapors in an immersion tank and improve the longevity of the coolant liquid and hardware within a tank of the immersion-cooling system. The dehumidifier can be a compressor dehumidifier, a desiccant dehumidifier, or another suitable dehumidifier that can capture water molecules from a gas mixture in the headspace of the tank that is used for the immersion-cooling system, such as any of the immersion-cooling systems described above in connection with FIG. 1 through FIG. 6B. It should be appreciated that various concepts introduced above and discussed in greater detail below may be implemented in multiple ways. Examples of specific implementations and applications are provided primarily for illustrative purposes.

[0124] 2.1 Immersion Tank and Compressor Dehumidifier

[0125] FIG. 8 depicts an immersion-cooling system 800 with a compressor type dehumidifier 820 and a gas management system 830 for removing humidity from the headspace 114 of an immersion tank 110. The immersion-cooling system 800 can be implemented as a two-phase immersion-cooling system, as depicted in FIG. 8. Alternatively, the immersion-cooling system 800 can be a single-phase immersion-cooling system. When implemented as a single-phase system, the condenser 132 and related condensing apparatus are not needed.

[0126] The immersion-cooling system 800 comprises the sealed immersion tank 110 that holds one or more computing components 802, such as servers, graphics processing units(GPUs), memory, power supplies, or switches, which can be operably connected to other computing components or systems outside the immersion tank 110, e.g., via wired and / or wireless communication links and wired power connections. Communication links can be part of a local area network, a medium area network, a wide area network such as the internet, and / or another computer network. The computing components 802 are immersed in thermally conductive dielectric coolant liquid 150 (also referred to more simply as “coolant”). An example of a coolant liquid 150 is fluoroketone. Preferably the coolant liquid 150 is an inert fluid. However, the coolant liquid 150 may react with water (e.g. H2O) and / or water vapor (e.g., H2O (g)) if there is any water or water vapor present in the immersion tank 110. The reaction of the coolant liquid 150 with water and / or water vapor may result in decomposition of the coolant liquid 150 and the formation of an acid (e.g., an organic acid), which may lead to the corrosion of metals (such as, but not limited to: zinc, aluminum, magnesium, and / or other galvanic metals). Such metals can be present in the immersion tank 110 (e.g., disposed on or within the computing components 802). An example of coolant liquid 150 is Novec™ 649 produced by 3M™. An exemplary coolant liquid 150 used in accordance with embodiments of the present invention may have a dielectric constant baseline value of about 1.8-2 at a frequency of about 1 kHz.

[0127] If the immersion-cooling system 800 is a two-phase immersion-cooling system, it also comprises a condenser 132 circulating chilled water or another suitable chilled fluid for heat exchange. The condenser 132 serves as a site for coolant-liquid vapor 140 to condense back to liquid phase producing droplets 815 that fall back into the coolant liquid 150. Pipes or conduits 812 and a pump 813 connect the condenser 132 to a heat rejection sub-system 814, such as a heat exchanger, chilled water loop, evaporative cooling tower, dry cooler, or other suitable mechanism for dissipating heat.

[0128] The immersion-cooling system 800 can further comprise the compressor dehumidifier 820 that is fluidically coupled to the headspace 114 of the immersion tank 110. In some implementations, the compressor dehumidifier 820 can be located in the headspace 114 above the coolant liquid 150 within the tank 110. In some implementations, at least a portion or a majority of the components of compressor dehumidifier 820 can be located outside the immersion tank 110. Duct work can direct the gas mixture from the headspace 114 into and through the compressor dehumidifier 820 and back into the immersion tank 110 or outside the immersion tank.

[0129] The compressor dehumidifier is configured to remove water molecules (e.g., watervapor) from the headspace 114 of the tank 110 so that the water vapor will not be condensed by the condenser 132 into liquid water 805, which may then drop into and react with the coolant liquid 150 and / or corrode metal parts in the tank 110. The compressor dehumidifier 820 functions to remove water vapor that may be introduced into the immersion tank 110 by servicing or air ingestion during negative pressure events. For example, the compressor dehumidifier 820 can be used to manage the intake of air into the immersion tank 110 in the event that a flow valve 837 leaks or fails due to a negative pressure event (such as a quick shut down of the immersion-cooling system 800) and admits moisture from the ambient environment into the tank 110. The moisture admitted into the tank 110 may be in the form of water vapor in air or liquid water.

[0130] The compressor dehumidifier 820 can remove moisture that is present in the immersion tank 110 and leave non-condensable gases (e.g., nitrogen (N2) or argon (Ar)). In some implementations, the compressor dehumidifier 820 can circulate the vapor mixture within the tank 110 after removing moisture from the mixture or exhaust heated mixture from the tank to help regulate pressure within the tank 110. For example, the dried, warmed mixture from the compressor dehumidifier 820 can be recycled within the immersion tank 110 to increase or maintain the pressure of the tank 110. The compressor dehumidifier 820 can further fluidically couple to a gas port or valve 851 that can be opened (e.g., by a system controller) to exhaust the warmed mixture from the tank 110 (e.g., if the pressure in the tank becomes too high).

[0131] In some cases, the immersion-cooling system 800 can comprise a humidity sensor 806. The humidity sensor 806 can be located in the headspace 114 of the tank 110 and can sense the relative humidity of the tank 110. Preferably the relative humidity in the headspace 114 of the tank 110 is in the range from approximately or exactly 20% to approximately or exactly 50%, or any subrange therebetween. More preferably the relative humidity is in the range from approximately or exactly 20% to approximately or exactly 30%. The humidity sensor 806 can be operably connected to other computing components or systems outside the immersion tank 110, e.g., via wired and / or wireless communication links and wired power connections. The humidity sensor 806 can control the activation of the compressor dehumidifier 820 when humidity in the headspace 114 rises above a first threshold value and deactivation of the compressor dehumidifier 820 when humidity in the headspace 114 falls below a second threshold value. The second threshold value can be the same as or lower than the first threshold value. The humidity sensor 806 can also indicate if the compressordehumidifier 820 fails or stops working e.g., evidenced as an uncontrollable, continuous increase in the relative humidity within the headspace 114 beyond the first threshold value).

[0132] The compressor dehumidifier 820 comprises an evaporator 821, a condenser 822, a compressor 823, and a collection tank 824. The evaporator 821 can cool the moist gas mixture from the tank 110 and condense the water 805 (e.g., H2O) from the moist gas mixture in the immersion tank 110. The evaporator 821 can comprise coils filled, at least in part, with a cool gas (evaporated from a liquid circulating in the dehumidifier 820) at or below the dew point for water vapor in the headspace 114 for a desired humidity level and operating temperature in the headspace 114. For example, if the desired humidity level is 50% and the operating temperature in the headspace is 30 °C, then the temperature of the evaporator should be approximately 18.4 °C.

[0133] The water 805 extracted from the evaporator 821 can fall into the collection tank 824 for collection. The condenser 822 can warm the gas mixture after the gas mixture has passed over the evaporator 821 and before the now drier mixture leaves the compressor dehumidifier 820. The condenser 822 can contain coils filled, at least in part, with a gas. The evaporator 821 and condenser 822 can be fluidically coupled with a first pipe 825. The evaporator 821 can be fluidically coupled to the compressor 823 with a second pipe 826. The condenser 822 can be fluidically coupled to the compressor 823 with a third pipe 827. The collection tank 824 can capture and collect the condensed water 805. The condensed water 805 can be removed from the immersion system 800 via a conduit 828 (such as a pipe) that passes through a wall of the immersion tank 110 and transports the water to a region outside the immersion tank. The conduit 828 may or may not couple into a storage tank 829 where the condensed water 805 is collected outside of the immersion-cooling system 800. The conduit 828 can be sealed to the wall of the immersion tank 110 where it passes through the wall so that no liquid or gas leaks from the tank 110.

[0134] The compressor dehumidifier 820 can be used to extract water from the immersion tank 110 instead of a desiccant box, for example, which would require regular servicing and opening of the immersion tank 110 of located inside the tank. The compressor dehumidifier 820 allows for an active management of the humidity in the immersion tank 110, which may provide a more constant and reliable level of humidity than humidity control with a humidity sensor and a desiccant box. The compressor dehumidifier 820 can be used continuously while the immersion-cooling system is in operation for active management of the vapor and humidity in the tank 110. In some implementations, the compressor dehumidifier 820 can beused intermittently (e.g., after the immersion tank 110 has been opened for servicing of the system or during periods of high ambient humidity). In some cases, the compressor dehumidifier 820 can assist with pre-treating of the computing components 802 (e.g., drying out the computing components 802 and / or heating up the computing components 802 to encourage the removal of water present in any cables or plastic in the tank 110 prior to filling the tank with coolant liquid 150). The compressor dehumidifier 820 can be designed to operate in an immersion-cooling system 800 and a fluoroketone environment. For example, components of the compressor dehumidifier 820 exposed to the gas mixture in the headspace 114 can comprise metal, polymers, and / or other materials resistant to corrosion by gases in the mixture and acids formed from gases in the mixture.

[0135] 2.2 Gas Management System

[0136] The immersion-cooling system 800 can further comprise a gas management system 830. The gas management system comprises a purge-control, a non-condensable gas sensor831 and a release valve 832. The gas sensor 831 can comprise one or more gas sensors to detect one or more types of gases such as, but not limited to, oxygen, a noble gas, and / or a halogen gas. When the gas sensor 831 detects at least an amount of a non-condensable gas (e.g., a concentration of oxygen 833 (O2)) that is at or above a first threshold set for the system for the non-condensable gas, a controller 880 of the system can open the release valve832 to allow the oxygen 833 to leave the immersion tank 110. When the gas sensor 831 detects an amount of a halogen (e.g., fluorine concentration in vapor from the coolant liquid 150) that is at or above a second threshold set for the system, the system controller 880 can close the release valve 832. The release valve 832 can also be closed when the gas sensor 831 detects an amount (concentration) of the dry gas 835 replacement. The release valve 832 can also be used to let at least some of the gas mixture in the headspace 114 out of the immersion tank 110 (e.g., in an emergency event when the pressure inside the tank 110 becomes too high such that bellows coupled to the tank could rupture). For example, if the pressure of in tank 110 rises above a threshold pressure value (e.g., 1 PSI above atmospheric pressure), release valve 832 can be opened to let gas out of the tank 110 and reduce the pressure in the headspace. Other overpressure threshold values can be used, such as any value between 0.5 PSI and 20 PSI above atmospheric pressure. In some implementations, the release valve 832 can comprise a vapor barrier 838 to block the flow of coolant-liquid vapor 140 from leaving the tank 110 through the release valve 832. The vapor barrier 838 can comprise a membrane with micrometer-scale or nanometer-scale holes that are sized to blockthe flow of coolant-liquid vapor 140 past the vapor barrier 838, and yet allow the flow of certain non-condensable molecules (e.g., oxygen) to pass through the vapor barrier 838. In some cases, the vapor barrier 838 can also block the flow of the dry gas 835 (e.g., nitrogen) through the barrier 838. In some implementations, the vapor barrier 838 can comprise an activated filter to capture coolant-liquid vapor 140. The vapor barrier 838 may comprise a molecular sieve, desiccant, adsorbent, or some combination thereof.

[0137] The system controller 880 can comprise at least one processing device and may comprise a combination of processing devices. Example processing devices that can be used in the controller 880 include, but are not limited to: microprocessor, microcontroller, programmable logic controller (PLC), field-programmable gate array (FPGA), digital signal processor (DSP), application-specific integrated circuit (ASIC), digital logic chips, and transistors. In some cases, the controller 880 can further include discrete electronic components (e.g., resistors, capacitors, inductors, etc.), at least one display element (e.g., light indicator, liquid-crystal display (LCD), an LCD or LED monitor, a touchscreen, etc.), and at least one input element (e.g., a touchscreen, keypad or keyboard, button, switch, etc.). In some implementations, the controller 880 comprises a tablet computer, laptop computer, smartphone, or other packaged computing device. The system controller can receive information from any of the sensors in the immersion tank and from other devices in the immersion tank 110 that are communicatively coupled to the system controller 880. A device that is communicatively coupled to the system controller 880 may or may not provide information to the system controller. For example, the system controller 880 can provide commands to operate a device that is communicatively coupled to the system controller 880 (such as a valve), wherein the controlled device does not provide information back to the system controller 880.

[0138] The gas management system 830 can further comprise a gas replacement chamber 834 that can be filled with a dry gas 835 (e.g, nitrogen or argon). The gas replacement chamber 834 is fluidically coupled to the immersion tank 110 via a conduit 836 (such as a pipe or tube). The flow of the dry gas 835 into the immersion tank 110 can be admitted or blocked by the flow valve 837, which can be mounted on the tank (e.g, at a gas port) or along the conduit 836. The dry gas 835 can be used for selective purging of the immersion tank 110 (e.g., to remove air laden with water vapor and / or oxygen from the immersion tank 110) or to replace gas in the immersion tank 110 (e.g., prior to running the immersion-cooling system 800 and / or replacing water vapor removed from the headspace during operation tomaintain gas pressure). The flow valve 837 can also be used to let the dry gas 835 into the tank 110 if the pressure in the tank 110 becomes too low. For example, if the pressure in the tank 110 falls, for example, 0.5 PSI below atmospheric pressure, the flow valve 837 can be opened to let the dry gas 835 into the tank 110. Other underpressure values can be used, such as any value between 0.25 PSI and 10 PSI below atmospheric pressure. The flow valve 837 can be controlled by the system controller 880.

[0139] In some implementations, the gas replacement chamber 834 can be pressurized at a pressure greater than the pressure in the headspace 114, so that the dry gas naturally flows into the headspace 114 when the flow valve 837 is opened. Such a pressure differential can prevent water vapor from flowing back into the gas replacement chamber 834. In some cases, a gas pump can be fluidically coupled between the gas replacement chamber 834 and the immersion tank 110. The gas pump can be used to achieve bidirectional flow through the flow valve 837 against a pressure differential. According to some implementations, the pressure in the gas replacement chamber 834 is approximately equal to the gas pressure in the headspace 114 of the immersion tank 110. Pressure differentials arising from operation of the immersion-cooling system 800 can determine the direction of flow of gases between the gas replacement chamber 834 and the immersion tank 110. In some cases, a pressure sensor 853 is mounted in the immersion tank to detect gas pressure in the headspace 114. The pressure sensor 853 can be communicatively coupled to the system controller 880. A second pressure sensor can be mounted in the gas replacement chamber 834 and also communicatively coupled to the system controller 880. In some cases, the system controller 880 can control the opening and closing of the flow valve 837 in response to pressure levels detected in the headspace 114 and / or in response to pressure differentials detected between the gas replacement chamber 834 and the headspace 114.

[0140] In operation, the gas management system 830 provides flow of a non-condensable gas (e.g., dry gas 835 such as nitrogen and / or argon) from the gas replacement chamber 834 into the immersion tank 110 via conduit 836 and flow valve 837 (e.g., during an underpressure event) and from the tank 110 to the gas replacement chamber 834 (e.g., during an overpressure event) as appropriate. The gas management system 830 can be used in combination with the compressor dehumidifier 820. For example, both the gas management system 830 and the compressor dehumidifier 820 can run at the same time. The gas management system 830 can be run whenever the computing components 802 are operating to compensate for load cycles and / or changes in operation of the immersion-cooling system800. For example, when the immersion-cooling system 800 is turned on or computing loads of the computing components 802 increase (causing an increase in vapor pressure in the headspace 114), the flow valve 837 can be opened to allow mostly dry gas 835 in the upper portion of the headspace 114 (since the dry gas may be lighter than coolant-liquid vapor 140) to flow from the tank 110 into the gas replacement chamber 834 to regulate pressure and then closed once pressure has stabilized to a desired operating pressure. When the immersioncooling system 800 is turned off or computing loads decrease (causing a reduction in pressure in the headspace 114), the flow valve 837 can be opened to allow the dry gas 835 into the tank 110 to regulate pressure and then closed once pressure has stabilized to the desired operating pressure (which may be 1 atm, for example). In some cases, the gas management system 830 can increase the efficiency of the condenser 132 by removing oxygen 833 and / or other non-condensable gasses (e.g., dry gas 835) from the tank 110, increasing the relative vapor pressure of coolant-liquid vapor 140 at the condenser 132.

[0141] According to some implementations, the gas management system 830 and compressor dehumidifier 820 are located above the condenser 132 with respect to the surface of Earth where the tank 110 is installed. Locating the gas management system 830 above the condenser 132 can take advantage of the lightness of water vapor, non-condensable gases, and dry gases (collecting in higher concentrations near the top of the headspace 114) compared to the heavier coolant-liquid vapor 140 (collecting in a higher concentration near the bottom of the headspace 114). In such an arrangement, the gas management system 830 can preferentially operate more on the lighter gases than the heavier coolant-liquid vapor.

[0142] In some cases, the flow valve 837 can further be operated (e.g., by the system controller 880) as an emergency shut-down valve. For example, if the immersion-cooling system 800 is shut down quickly, gas may be admitted into the immersion tank 110 to avoid an unwanted underpressure in the tank. If air from the ambient environment were pulled in, the inflowing air can undesirably introduce moisture into the immersion tank 110. Instead, the flow valve 837 can be opened in an emergency shut down to allow a dry gas 835, free of moisture, from the gas replacement chamber 834 into the tank 110 instead of air, thereby reducing the introduction of moisture into the immersion tank 110. In some implementations, the flow valve 837 can be, or can be operated as, a one-way check valve that only allows flow of dry gas 835 from the gas replacement chamber 834 into the tank 110 when the pressure in the headspace 114 falls to or below a threshold value. One-way check valve functionality can prevent contamination of the dry gas 835 with moisture. During overpressure events, gas canbe exhausted from the tank through another valve (e.g. release valve 832).

[0143] The gas management system 830 and compressor dehumidifier 820 can be used in combination with one or more bellows described above, which may also help maintain the saturation pressure of coolant-liquid vapor 140 in the tank 110.

[0144] FIG. 9 depicts another implementation of a two-phase immersion-cooling system 900 in which the immersion tank 110 is fluidically coupled to an auxiliary tank 940. The immersion-cooling system 900 comprises a compressor dehumidifier 820 and a gas management system 830 as described above. Like numbered elements of the immersioncooling system 900 described in connection with FIG. 8 operate in the same way and need not be described again for the implementation of FIG. 9. In some cases, the immersioncooling system 900 may be implemented as a single-phase immersion-cooling system. When implemented as a single-phase system, the condenser 132 and related condensing apparatus are not needed.

[0145] The immersion-cooling system 900 further comprises an auxiliary tank 940. The auxiliary tank 940 can be filled, at least in part, with coolant liquid 150 and can be fluidically coupled to the immersion tank 110 through a conduit 941 such as a pipe or tube. A pump 942 couple to the conduit can pump coolant liquid 150 from the auxiliary tank 940 into the immersion tank 110, for example to fill, at least partially, re-fill or re-supply the coolant liquid 150 in the immersion tank 110.

[0146] In operation, after closing a service door to the immersion tank 110 (which can seal the tank), the immersion tank 110 can be filled with the dry gas 835 to displace any oxygen 833 and water vapor present in the immersion tank 110 that may have entered when the tank was open to the ambient environment. The oxygen 833 and water vapor present inside the sealed immersion tank 110 can be exhausted through the release valve 832 when dry gas flows in to fill the tank 110. Alternatively, or in combination with the influx of dry gas 835, the compressor dehumidifier 820 can be run for a period of time prior to admitting coolant liquid into the tank to reduce the amount of water vapor inside the immersion tank 110, some of which may have absorbed into components in the immersion tank 110. The period of time during which the compressor dehumidifier 820 runs can be from 15 minutes to 12 hours or longer. In some cases, the compressor dehumidifier 820 can run from 15 minutes to 4 hours to reduce relative humidity in the tank to less than 50% prior to filling the tank. Next, the immersion tank can be filled with coolant liquid 150 from the auxiliary tank 940 and the immersion-cooling system 900 can be turned on. This approach to initiating operation of theimmersion-cooling system after installment and / or servicing can mitigate the exposure of the coolant liquid 150 and / or coolant-liquid vapor 140 to oxygen and / or water inside the immersion tank 110.

[0147] 2.3 Desiccant Dehumidifier

[0148] FIG. 10 depicts an implementation of an immersion-cooling system 1000 with a desiccant dehumidifier 1020 that is fluidically coupled to the headspace 114 of the immersion tank 110. The immersion-cooling system 1000 can comprise a desiccant dehumidifier 1020 installed within the headspace 114 of the immersion tank 110. In some cases, at least a portion or a majority of components of the desiccant dehumidifier 1020 can be mounted external to the immersion tank, as described above in connection with FIG. 8. The immersion-cooling system 1000 can further comprise a gas management system 830 as described above in connection with FIG. 8. Like numbered elements of the immersioncooling system 1000 described in connection with FIG. 8 operate in the same way and need not be described again for the implementation of FIG. 10. In some cases, the immersioncooling system 1000 may be implemented as a single-phase immersion-cooling system. When implemented as a single-phase system, the condenser 132 and related condensing apparatus are not needed. The immersion-cooling system 1000 can also be a two-phase immersion-cooling system as depicted in FIG. 10.

[0149] The desiccant dehumidifier 1020 can extract water (e.g., H2O) from the gas mixture in the headspace 114 of the immersion tank 110. The desiccant dehumidifier 1020 can be located in the headspace 114 of the tank 110 to remove moisture located in the headspace 114 and reduce the condenser 132 from condensing any moisture in the tank 110 into liquid water, which can drop into and react with the coolant liquid 150. The desiccant dehumidifier 1020 can also re-circulate the dried gas mixture within the headspace 114 tank 110. In some cases, warmed gas mixture, after being dried by the desiccant dehumidifier 1020, can be recycled into the headspace 114 of the tank 110 to warm gases in the headspace and help regulate and maintain the pressure in the headspace 114. In some cases, gas output from the desiccant dehumidifier 1020 can exhaust from the headspace 114 using a valve 851 to remove warmed gases from the desiccant dehumidifier 1020 (e.g., if the pressure in the headspace 114 is too high).

[0150] The desiccant dehumidifier 1020 can be implemented in several ways. The desiccant dehumidifier 1020 can comprise a fan 1021 that moves gas mixture from the headspace 114 through the desiccant dehumidifier 1020 and across or through a desiccant material 1026(e.g., a silica gel). The desiccant material 1026 can absorb water molecules from the moist gas, thereby drying the gas mixture that passes over or through the desiccant material 1026. In some implementations, the desiccant material 1026 can be disposed on a rotor 1022 that turns to expose the desiccant material 1026 to moist gas and to regenerate the desiccant material 1026 after it becomes loaded with water molecules. Alternatively, there can be two or more chambers within the desiccant dehumidifier 1020. Each chamber contains desiccant material 1026. The chambers can alternate with each other between absorbing water for a first time period (e.g., 1 to 20 minutes) and regenerating the desiccant material for a second time period (e.g., 1 to 20 minutes).

[0151] When regenerating the desiccant material 1026 to remove moisture, the desiccant material 1026 can be heated with a heater 1023 to release water molecules. The moist air from regeneration of the desiccant material 1026 can, in some implementations, be directed through a heat exchanger 1024 that condenses the water molecules into water droplets that can be collected in a collection tank 824 and flow outside the immersion tank 110 through a conduit 828. In other implementations, the moist air from regeneration of the desiccant material 1026 can be blown outside the immersion tank 110.

[0152] The above-described desiccant dehumidifier 1020 can be run continuously or intermittently during operation of the immersion-cooling system 1000 without interrupting operation for frequent servicing of the desiccant dehumidifier 1020 (e.g., to regenerate or replace the desiccant material 1026). Such frequent servicing may be used in implementations where desiccant boxes are used without regeneration of the desiccant material 1026 inside the immersion tank 110. Desiccant boxes may be used instead of the desiccant dehumidifier 1020 in cases where the immersion-cooling system 1000 is operated in a low-humidity environment, dry gas purging of the chamber is used, the immersion tank 110 is well sealed, and admittance of ambient air into the tank is infrequent (e.g., occurring twice a month or less).

[0153] The immersion-cooling system 1000 can also comprise the humidity sensor 806, as in the system of FIG. 8. The humidity sensor 806 can be located in the headspace 114 of the tank 110 and participate in the control of the relative humidity within the headspace 114, as described above for the immersion-cooling system 800 of FIG. 8. For example, based on humidity levels sensed by the humidity sensor 806, the system controller 880 can activate the desiccant dehumidifier 1020 to lower relative humidity or deactivate the desiccant dehumidifier 1020 when a target relative humidity level is reached. The humidity sensor 806can also provide an indication if the desiccant dehumidifier 1020 fails or stops working (e.g., evidenced as an uncontrollable, continuous increase in the relative humidity within the headspace 114 beyond the first threshold value).

[0154] The immersion-cooling system 1000 can further comprise the gas management system 830 as described in connection with FIG. 8. The gas management system 830 need not be described again for the system of FIG. 10.

[0155] FIG. 11 depicts a two-phase immersion-cooling system 1100 that comprises the desiccant dehumidifier 1020, a gas management system 830, and an auxiliary tank 940 fluidically coupled to the immersion tank 110. Although a two-phase immersion-cooling system is depicted in the drawing, the immersion-cooling system 1100 can be implemented as a single-phase immersion-cooling system. In sing-phase implementations, the condenser 132 and associated condensing apparatus is not needed. The auxiliary tank 940 and its associated apparatus are described above in connection with the system of FIG. 9 and need not be described again for the immersion-cooling system of FIG. 11. Like numbered elements of the immersion-cooling system 1100 described in connection with FIG. 8 and FIG. 9 operate in the same way and need not be described again for the implementation of FIG. 10.

[0156] Any of the immersion-cooling systems 800, 900, 1000, 1100 depicted in FIG. 8 through FIG. 11 can further include at least one bellows assembly 120 described elsewhere in this application in connection with FIG. 1 through FIG. 7.

[0157] Coolant-vapor handling for immersion-cooling systems can be implemented in different configurations and operated according to different methods, some of which are listed below.(1) A method of cooling semiconductor dies in an immersion tank of a two-phase immersion-cooling system, the method comprising: receiving heat from the semiconductor dies into a coolant liquid within the immersion tank, the coolant liquid filling a portion of the immersion tank below a headspace that occupies a top region of the immersion tank, the headspace filling a first portion of a first volume that is normally closed and contains a gas during operation of the two-phase immersion-cooling system; and receiving a first amount of the gas from the headspace into a second volume enclosed by a container of a bellows assembly in response to an increase in pressure of the gas in the headspace. The second volume comprises a second portion of the first volume. The bellows assembly can comprise: the container, a gas port mounted in the container and fluidically coupled to the headspace,and an isolation valve fluidically coupled between the gas port and the headspace. The method can further comprise deforming a first wall of the container in a first direction to increase the second volume while receiving the first amount of the gas; detecting, by a controller of the two-phase immersion-cooling system, an event that would allow a second amount of the gas from the second volume to flow into the headspace and displace a third amount of the gas from the headspace into an ambient environment around the immersion tank; and closing the isolation valve to isolate the second volume from the headspace in response to detecting the event to prevent at least a portion of the second amount of the gas from flowing into the headspace and causing displacement of the third amount of the gas from the headspace into the ambient environment.(2) The method of (1), wherein the event comprises detecting an opening of an access door to an interior of the immersion tank.(3) The method of (1), wherein the event comprises detecting a rate of reduction in the pressure of the gas in the headspace that exceeds a threshold rate of reduction.(4) The method of any one of (1) through (3), further comprising: draining condensate from the container through a drain port located at a base of the container; filtering the condensate drained from the container to produce a filtered condensate; and returning the filtered condensate to the immersion tank.(5) The method of (4), wherein filtering the condensate and returning the filtered condensate comprises using gravitational force to flow the condensate drained from the container through a filter and into the immersion tank.(6) The method of (4) or (5), wherein returning the filtered condensate comprises pumping the condensate drained from the container to the immersion tank.(7) The method of (4), wherein filtering the condensate comprises removing particulates from the condensate drained from the container.(8) The method of (4), wherein filtering the condensate comprises using an activated substance to remove a chemical contaminant from the condensate drained from the container.(9) The method of (4), wherein filtering the condensate comprises using a hygroscopic substance to remove water from the condensate drained from the container.(10) The method of any one of (1) through (9), wherein the container comprises a polymer, the method further comprising rupturing a membrane of a burst valve at a first pressure that is lower than a second pressure that would rupture the polymer of the container.(11) The method of (10), wherein the burst valve is mounted to the container.(12) The method of (10), wherein the burst valve is mounted to a conduit assembly that fluidically couples the container to the headspace.(13) The method of any one of (10) through (12), wherein the burst valve is located within a top quarter of the first volume.(14) The method any one of (1) through (13), further comprising releasing, with a pressurerelease valve, a fourth amount of the gas from the second volume into an ambient environment outside the container when pressure of the gas in the second volume exceeds a threshold value that is lower than a rupture strength of the container.(15) The method of (14), wherein the pressure-release valve is located is located within 10 cm of a top edge of the container such that the fourth amount of the gas released from the second volume contains a lower percentage of coolant-liquid vapor from coolant liquid used in the two-phase immersion-cooling system than if the pressure-release valve were located at a lower elevation on the container.(16) The method of (14) or (15), further comprising: blocking passage of coolant-liquid vapor from the headspace to the pressure-release valve with a vapor barrier; and passing air molecules through the vapor barrier to the pressure-release valve.(17) The method of any one of (1) through (16), wherein the first wall and second wall deform away from each other and toward each other in directions that are approximately horizontal when receiving the first amount of the gas into the second volume and when expelling the first amount of the gas from the second volume, respectively.(18) The method of any one of (1) through (17), wherein the first wall and second wall deform away from each other and toward each other in directions that are approximately vertical when receiving the first amount of the gas into the second volume and when expelling the first amount of the gas from the second volume, respectively.(19) A two-phase immersion-cooling system comprising: an immersion tank to contain oneor more printed circuit boards having semiconductor dies to be cooled via two-phase immersion cooling during operation of the semiconductor dies; and a bellows assembly to fluidically couple to a headspace within the immersion tank and form a normally-closed first volume that includes the headspace to contain a gas during operation of the two-phase immersion-cooling system. The bellows assembly can comprise: a container comprising a polymer and enclosing a second volume that is a portion of the normally-closed first volume, the container having a first surface spanning a first surface area that encloses the second volume, wherein at least a portion of the container is reversibly deformable to increase and decrease an amount of the second volume enclosed by the container; a first wall comprising the polymer and having a second surface spanning a second surface area; a second wall having a third surface spanning a third surface area, wherein the second surface area and the third surface area comprise a majority of the first surface area; and a gas port mounted to the container to admit a first amount of the gas into the second volume from the headspace within the immersion tank when the gas in the headspace is at a first pressure that is higher than a second pressure of the gas in the second volume, wherein the gas port can further admit a second amount of the gas from the second volume into the headspace when the first pressure is lower than the second pressure. The two-phase immersion-cooling system can further comprise a controller; and an isolation valve to fluidically couple between the immersion tank and the bellows assembly, wherein the controller is configured to issue a command to close the isolation valve to isolate the second volume from the headspace in response to the controller detecting an event that would allow a third amount of the gas from the second volume to displace a fourth amount of the gas from the headspace into an ambient environment around the immersion tank if the isolation valve were not closed.(20) The two-phase immersion-cooling system of configuration (19), wherein the event comprises detecting an opening of an access door to an interior of the immersion tank.(21) The two-phase immersion-cooling system of configuration (19), wherein the event comprises detecting a rate of reduction in the first pressure that exceeds a threshold rate of reduction.(22) The two-phase immersion-cooling system of any one of configurations (19) through (21), wherein the container further comprises: a third wall connected between the first wall and the second wall; and at least one hardware element attached to at least one of the first wall, the second wall, and the third wall to mount the container in an orientation such that atleast one of the first wall and the second wall deforms or deform outward from a center of the container without external hinderance when the normally-closed first volume is under pressure.(23) The two-phase immersion-cooling system of configuration (22), wherein the second wall and the third wall also comprise the polymer.(24) The two-phase immersion-cooling system of any one of configurations (19) through (23), wherein the bellows assembly further comprises a burst valve comprising: a membrane to rupture at a third pressure that is lower than a fourth pressure that would rupture the polymer of the container.(25) The two-phase immersion-cooling system of configuration (24), wherein the burst valve is mounted in the first wall or second wall of the container.(26) The two-phase immersion-cooling system of configuration (24) or (25), further comprising: a conduit assembly to fluidically couple the container, the isolation valve, and the headspace, wherein the burst valve is mounted in the conduit assembly.(27) The two-phase immersion-cooling system of any one of configurations (24) through(26), wherein the gas port comprises a flange assembly that includes the burst valve.(28) The two-phase immersion-cooling system of any one of configurations (19) through(27), wherein the bellows assembly further comprises a drain port, the drain port arranged to remove condensate from inside the container.(29) The two-phase immersion-cooling system of configuration (28), further comprising a filter fluidically coupled to the drain port to filter the condensate removed from an inside of the container.(30) The two-phase immersion-cooling system of configuration (29), wherein the filter comprises a sieve to capture particulates from the condensate.(31) The two-phase immersion-cooling system of configuration (29), wherein the filter comprises an activated substance to capture a chemical contaminant from the condensate.(32) The two-phase immersion-cooling system of configuration (29), wherein the filter comprises a hygroscopic substance to remove water from the condensate.(33) The two-phase immersion-cooling system of any one of configurations (28) through (32), wherein the gas port comprises a flange assembly that includes the drain port.(34) The two-phase immersion-cooling system of any one of configurations (28) through (32), wherein the gas port comprises a flange assembly that includes the drain port and a burst valve, the burst valve comprising: a membrane to rupture at a third pressure that is lower than a fourth pressure that would rupture the polymer of the container.(35) The two-phase immersion-cooling system of any one of configurations (19) through (34), further comprising: a pressure-release valve located within 10 cm from an edge of the first wall and fluidically coupled to the second volume such that a fifth amount of the gas can be released from the second volume by the pressure-release valve when pressure within the second volume exceeds a threshold value.(36) The two-phase immersion-cooling system of configuration (35), wherein the pressurerelease valve is located within 10 cm of a top edge of the container such that, when the bellows assembly is in use in the two-phase immersion-cooling system, the fifth amount of the gas released from the second volume contains a lower percentage of coolant-liquid vapor from coolant liquid used when the two-phase immersion-cooling system is in operation than if the pressure-release valve were located at a lower elevation on the first wall.(37) The two-phase immersion-cooling system of configuration (36), further comprising: a pressure-release valve fluidically coupled to the second volume such that the fifth amount of the gas can be released from the second volume when pressure within the second volume exceeds a threshold value; and a vapor barrier arranged to transmit air to the pressure-release valve and to block passage of coolant-liquid vapor from coolant liquid used when the two- phase immersion-cooling system is in operation.(38) The two-phase immersion-cooling system of any one of configurations (19) through (37), further comprising: an access door on the immersion tank to access an interior region of the immersion tank; and a sensor to detect opening of the access door, wherein the controller is configured to receive a signal from the sensor indicating an opening of the access door and issue a command signal to activate the isolation valve in response to receiving the signal to isolate the headspace in the immersion tank from the second volume.(39) The two-phase immersion-cooling system of any one of configurations (19) through (38), wherein the first wall and second wall deform away from and toward each other in directions that are approximately horizontal, when the bellows assembly is in use in the two- phase immersion-cooling system.(40) The two-phase immersion-cooling system of any one of configurations (19) through (38), wherein the first wall and second wall deform away from and toward each other in directions that are approximately vertical, when the bellows assembly is in use in the two- phase immersion-cooling system.(41) The two-phase immersion-cooling system of any one of configurations (19) through(40), wherein a thickness of the first wall between 0.1 mm and 3 mm.(42) The two-phase immersion-cooling system of any one of configurations (19) through(41), wherein the polymer comprises polyurethane.(43) The two-phase immersion-cooling system of any one of configurations (19) through(42), wherein the first wall and the second wall have a same rectangular shape.(44) The two-phase immersion-cooling system of any one of configurations (19) through(43), wherein a ratio of the second volume to a volume of the headspace is in a range from 0.4 to 1.5.(45) An immersion-cooling system comprising: an immersion tank to hold at least one computing component immersed in a coolant liquid within the immersion tank; a dehumidifier fluidically coupled to a headspace of the immersion tank, the dehumidifier configured to capture water molecules from a gas mixture in the headspace of the immersion tank; and a gas replacement chamber, fluidically coupled to the immersion tank, configured to supply a first amount of a dry gas to replace the water molecules captured from the gas mixture in the headspace of the immersion tank.(46) The immersion-cooling system of configuration (45), wherein the dehumidifier is a compressor dehumidifier.(47) The immersion-cooling system of configuration (45), wherein the dehumidifier is a desiccant dehumidifier.(48) The immersion-cooling system of any one of configurations (45) through (47), further comprising: a collection tank, in fluid communication with the dehumidifier, to collect water from the dehumidifier; and a conduit passing through a wall of the immersion tank to remove water from the collection tank to a region outside the immersion tank.(49) The immersion-cooling system of any one of configurations (45) through (48), further comprising: a gas sensor disposed in the headspace to detect a non-condensable gas; and a release valve mounted to the immersion tank to release the non-condensable gas from the headspace of the immersion tank in response to detection of an amount of the non- condensable gas at or above a first threshold amount, wherein the gas replacement chamber is further configured to supply a second amount of the dry gas to replace the non-condensable gas released from the headspace of the immersion tank.(50) The immersion-cooling system of configuration (49), wherein the non-condensable gas is oxygen.(51) The immersion-cooling system of configuration (49) or (50), further comprising: a system controller communicatively coupled to the gas sensor and to the release valve, wherein the system controller is configured to open the release valve in response to receiving information from the gas sensor indicating the amount of the non-condensable gas is at or above a first threshold amount.(52) The immersion-cooling system of configuration (51), wherein: the gas sensor is further configured to detect a halogen gas, and the system controller is further configured to close the release valve in response to receiving information from the gas sensor indicating an amount of the halogen gas is at or above a second threshold amount.(53) The immersion-cooling system of configuration (52), wherein the halogen gas comprises fluorine.(54) The immersion-cooling system of any one of configurations (51) through (53), further comprising: a flow valve fluidically coupled between the immersion tank and the gas replacement chamber, wherein: the system controller is communicatively coupled to the flow valve, and the system controller is further configured to open the flow valve to admit the dry gas into the headspace in response to releasing the non-condensable gas from the headspace.(55) The immersion-cooling system of any one of configurations (45) through (54), wherein the coolant liquid comprises a thermally conductive dielectric coolant liquid.(56) The immersion-cooling system of configuration (55), wherein the coolant liquid comprises a fluoroketone.(57) The immersion-cooling system of any one of configurations (45) through (56), wherein the dry gas comprises at least one of nitrogen or argon.(58) The immersion-cooling system of any one of configurations (45) through (57), further comprising an auxiliary chamber fluidically coupled to the immersion tank and configured to at least partially fill the immersion tank with the coolant liquid.(59) A method of removing water molecules from a gas mixture in a headspace of an immersion tank, the method comprising: cooling at least one computer component with a coolant liquid in the immersion tank; capturing the water molecules with a dehumidifier that is fluidically coupled to a headspace of the immersion tank; and admitting a first amount of dry gas into the headspace to replace the water molecules captured from the gas mixture, wherein the first amount of dry gas is admitted from a gas replacement chamber that is fluidically coupled to the immersion tank.(60) The method of (59), further comprising: collecting water from the dehumidifier into a collection tank that is in fluid communication with the dehumidifier; and removing water from the collection tank to a region outside the immersion tank using a conduit that passes through a wall of the immersion tank.(61) The method of (59) or (60), further comprising: detecting, with a gas sensor disposed in the headspace, a non-condensable gas in the headspace; and releasing, with a release valve mounted to the immersion tank, the non-condensable gas from the headspace of the immersion tank in response to detecting an amount of the non-condensable gas at or above a first threshold amount, wherein the gas replacement chamber further operates to supply a second amount of the dry gas to replace the non-condensable gas released from the headspace of the immersion tank.(62) The method of (61), wherein the non-condensable gas is oxygen.(63) The method of (61) or (62), wherein releasing the non-condensable gas comprises: receiving, by a system controller, information from the gas sensor; determining, by the system controller, that the amount of the non-condensable gas is at or above the first threshold amount based, at least in part, on the information received from the gas sensor; and controlling, by the system controller, the release valve to open in response to determining that the amount of the non-condensable gas is at or above the first threshold amount.(64) The method of (63), wherein the gas sensor is further configured to detect a halogen gas, the method further comprising: receiving, by the system controller, information from the gas sensor indicating an amount of the halogen gas in the headspace; determining, by the system controller, that the amount of the halogen gas is at or above a second threshold amount; and controlling, by the system controller, the release valve to close in response to determining that the amount of the halogen gas is at or above the second threshold amount.(65) The method of (64), wherein the halogen gas comprises fluorine.(66) The method of any one of (63) through (65), further comprising: controlling, by the system controller and in response to releasing the non-condensable gas from the headspace, a flow valve to open that is fluidically coupled between the immersion tank and the gas replacement chamber so that the second amount of dry gas is admitted into the immersion tank.(67) A method of filling an immersion tank of an immersion-cooling system with coolant liquid to cool at least one computing component, wherein the immersion-cooling system comprises: the immersion tank, a dehumidifier fluidically coupled to a headspace of the immersion tank, the dehumidifier configured to capture water molecules from a gas mixture in the headspace of the immersion tank, a gas replacement chamber, fluidically coupled to the immersion tank, configured to supply a first amount of a dry gas to replace the water molecules captured from the gas mixture in the headspace of the immersion tank, and an auxiliary chamber fluidically coupled to the immersion tank and configured to at least partially fill the immersion tank with the coolant liquid. The method of filling an immersion tank comprises: prior to filling the immersion tank with the coolant liquid, operating the dehumidifier to capture the water molecules from the gas mixture in at least the headspace of the immersion tank and from components in the immersion tank; supplying at least the first amount of the dry gas into the immersion tank; and after operating the dehumidifier for a period of time, filling the immersion tank with the coolant liquid from the auxiliary chamber.(68) The method of (67), further comprising prior to filling the immersion tank with the coolant liquid: detecting, with a gas sensor disposed in the headspace, a non-condensable gas in the headspace; and releasing, with a release valve mounted to the immersion tank, the non- condensable gas from the headspace of the immersion tank in response to detecting an amount of the non-condensable gas at or above a first threshold amount, wherein the gas replacement chamber further operates to supply a second amount of the dry gas to replace the non-condensable gas released from the headspace of the immersion tank.(69) The method of (68), wherein the non-condensable gas is oxygen.(70) The method of (68) or (69), wherein releasing the non-condensable gas comprises: receiving, by a system controller, information from the gas sensor; determining, by the system controller, that the amount of the non-condensable gas is at or above the first threshold amount based, at least in part, on the information received from the gas sensor; and controlling, by the system controller, the release valve to open in response to determining that the amount of the non-condensable gas is at or above the first threshold amount.(71) The method of (70), wherein the gas sensor is further configured to detect a halogen gas, the method further comprising: receiving, by the system controller, information from the gas sensor indicating an amount of the halogen gas in the headspace; determining, by the system controller, that the amount of the halogen gas is at or above a second threshold amount; and controlling, by the system controller, the release valve to close in response to determining that the amount of the halogen gas is at or above the second threshold amount.(72) The method of (71), wherein the halogen gas comprises fluorine.(73) The method of any one of (70) through (72), further comprising: controlling, by the system controller and in response to releasing the non-condensable gas from the headspace, a flow valve to open that is fluidically coupled between the immersion tank and the gas replacement chamber so that the second amount of dry gas is admitted into the immersion tank.

[0158] 3. Conclusion

[0159] 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 advantagesdescribed 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.

[0160] 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 an order different than illustrated, which may include performing some acts simultaneously, even though shown as sequential acts in illustrative embodiments.

[0161] 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.

[0162] 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.

[0163] The indefinite articles “a” and “an,” as used herein, unless clearly indicated to the contrary, should be understood to mean “at least one.”

[0164] 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 construedin 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.

[0165] 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.

[0166] 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 non-limiting 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.

[0167] In the specification above, all transitional phrases such as “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” “holding,” “composed of,” and the like are tobe 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.What is claimed is:

Claims

CLAIMS1. A method of cooling semiconductor dies in an immersion tank of a two-phase immersion-cooling system, the method comprising: receiving heat from the semiconductor dies into a coolant liquid within the immersion tank, the coolant liquid filling a portion of the immersion tank below a headspace that occupies a top region of the immersion tank, the headspace filling a first portion of a first volume that is normally closed and contains a gas during operation of the two-phase immersion-cooling system; receiving a first amount of the gas from the headspace into a second volume enclosed by a container of a bellows assembly in response to an increase in pressure of the gas in the headspace, wherein the second volume comprises a second portion of the first volume, the bellows assembly comprising: the container, a gas port mounted in the container and fluidically coupled to the headspace, and an isolation valve fluidically coupled between the gas port and the headspace; deforming a first wall of the container in a first direction to increase the second volume while receiving the first amount of the gas; detecting, by a controller of the two-phase immersion-cooling system, an event that would allow a second amount of the gas from the second volume to flow into the headspace and displace a third amount of the gas from the headspace into an ambient environment around the immersion tank; and closing the isolation valve to isolate the second volume from the headspace in response to detecting the event to prevent at least a portion of the second amount of the gas from flowing into the headspace and causing displacement of the third amount of the gas from the headspace into the ambient environment.

2. The method of claim 1, wherein the event comprises detecting an opening of an access door to an interior of the immersion tank.

3. The method of claim 1, wherein the event comprises detecting a rate of reduction in the pressure of the gas in the headspace that exceeds a threshold rate of reduction.

4. The method of claim 1, further comprising: draining condensate from the container through a drain port located at a base of thecontainer; filtering the condensate drained from the container to produce a filtered condensate; and returning the filtered condensate to the immersion tank.

5. The method of claim 4, wherein filtering the condensate and returning the filtered condensate comprises: using gravitational force to flow the condensate drained from the container through a filter and into the immersion tank.

6. The method of claim 4, wherein returning the filtered condensate comprises: pumping the condensate drained from the container to the immersion tank.

7. The method of claim 4, wherein filtering the condensate comprises removing particulates from the condensate drained from the container.

8. The method of claim 4, wherein filtering the condensate comprises using an activated substance to remove a chemical contaminant from the condensate drained from the container.

9. The method of claim 4, wherein filtering the condensate comprises using a hygroscopic substance to remove water from the condensate drained from the container.

10. The method of claim 1, wherein the container comprises a polymer, the method further comprising: rupturing a membrane of a burst valve at a first pressure that is lower than a second pressure that would rupture the polymer of the container.

11. The method of claim 10, wherein the burst valve is mounted to the container.

12. The method of claim 10, wherein the burst valve is mounted to a conduit assembly that fluidically couples the container to the headspace.

13. The method of claim 11 or 12, wherein the burst valve is located within a top quarter of the first volume.

14. The method of any one of claims 1 through 12, further comprising: releasing, with a pressure-release valve, a fourth amount of the gas from the second volume into an ambient environment outside the container when pressure of the gas in thesecond volume exceeds a threshold value that is lower than a rupture strength of the container.

15. The method of claim 14, wherein the pressure-release valve is located is located within 10 cm of a top edge of the container such that the fourth amount of the gas released from the second volume contains a lower percentage of coolant-liquid vapor from coolant liquid used in the two-phase immersion-cooling system than if the pressure-release valve were located at a lower elevation on the container.

16. The method of claim 14, further comprising: blocking passage of coolant-liquid vapor from the headspace to the pressure-release valve with a vapor barrier; and passing air molecules through the vapor barrier to the pressure-release valve.

17. The method of any one of claims 1 through 12, wherein the first wall and second wall deform away from each other and toward each other in directions that are approximately horizontal when receiving the first amount of the gas into the second volume and when expelling the first amount of the gas from the second volume, respectively.

18. The method of any one of claims 1 through 12, wherein the first wall and second wall deform away from each other and toward each other in directions that are approximately vertical when receiving the first amount of the gas into the second volume and when expelling the first amount of the gas from the second volume, respectively.

19. A two-phase immersion-cooling system comprising: an immersion tank to contain one or more printed circuit boards having semiconductor dies to be cooled via two-phase immersion cooling during operation of the semiconductor dies; a bellows assembly to fluidically couple to a headspace within the immersion tank and form a normally-closed first volume that includes the headspace to contain a gas during operation of the two-phase immersion-cooling system, the bellows assembly comprising: a container comprising a polymer and enclosing a second volume that is a portion of the normally-closed first volume, the container having a first surface spanning a first surface area that encloses the second volume, wherein at least a portion of the container is reversibly deformable to increase and decrease an amount of the second volume enclosed by the container;a first wall comprising the polymer and having a second surface spanning a second surface area; a second wall having a third surface spanning a third surface area, wherein the second surface area and the third surface area comprise a majority of the first surface area; and a gas port mounted to the container to admit a first amount of the gas into the second volume from the headspace within the immersion tank when the gas in the headspace is at a first pressure that is higher than a second pressure of the gas in the second volume, wherein the gas port can further admit a second amount of the gas from the second volume into the headspace when the first pressure is lower than the second pressure; a controller; and an isolation valve to fluidically couple between the immersion tank and the bellows assembly, wherein the controller is configured to issue a command to close the isolation valve to isolate the second volume from the headspace in response to the controller detecting an event that would allow a third amount of the gas from the second volume to displace a fourth amount of the gas from the headspace into an ambient environment around the immersion tank if the isolation valve were not closed.

20. The two-phase immersion-cooling system of claim 19, wherein the event comprises detecting an opening of an access door to an interior of the immersion tank.

21. The two-phase immersion-cooling system of claim 19, wherein the event comprises detecting a rate of reduction in the first pressure that exceeds a threshold rate of reduction.

22. The two-phase immersion-cooling system of claim 19, wherein the container further comprises: a third wall connected between the first wall and the second wall; and at least one hardware element attached to at least one of the first wall, the second wall, and the third wall to mount the container in an orientation such that at least one of the first wall and the second wall deforms or deform outward from a center of the container without external hinderance when the normally-closed first volume is under pressure.

23. The two-phase immersion-cooling system of claim 22, wherein the second wall and the third wall also comprise the polymer.

24. The two-phase immersion-cooling system of claim 19, wherein the bellows assembly further comprises a burst valve comprising: a membrane to rupture at a third pressure that is lower than a fourth pressure that would rupture the polymer of the container.

25. The two-phase immersion-cooling system of claim 24, wherein the burst valve is mounted in the first wall or second wall of the container.

26. The two-phase immersion-cooling system of claim 24, further comprising: a conduit assembly to fluidically couple the container, the isolation valve, and the headspace, wherein the burst valve is mounted in the conduit assembly.

27. The two-phase immersion-cooling system of claim 24, wherein the gas port comprises a flange assembly that includes the burst valve.

28. The two-phase immersion-cooling system of claim 19, wherein the bellows assembly further comprises a drain port, the drain port arranged to remove condensate from inside the container.

29. The two-phase immersion-cooling system of claim 28, further comprising a filter fluidically coupled to the drain port to filter the condensate removed from an inside of the container.

30. The two-phase immersion-cooling system of claim 29, wherein the filter comprises a sieve to capture particulates from the condensate.

31. The two-phase immersion-cooling system of claim 29, wherein the filter comprises an activated substance to capture a chemical contaminant from the condensate.

32. The two-phase immersion-cooling system of claim 29, wherein the filter comprises a hygroscopic substance to remove water from the condensate.

33. The two-phase immersion-cooling system of claim 28, wherein the gas port comprises a flange assembly that includes the drain port.

34. The two-phase immersion-cooling system of claim 28, wherein the gas port comprises a flange assembly that includes the drain port and a burst valve, the burst valve comprising:a membrane to rupture at a third pressure that is lower than a fourth pressure that would rupture the polymer of the container.

35. The two-phase immersion-cooling system of any one of claims 19 through 34, further comprising: a pressure-release valve located within 10 cm from an edge of the first wall and fluidically coupled to the second volume such that a fifth amount of the gas can be released from the second volume by the pressure-release valve when pressure within the second volume exceeds a threshold value.

36. The two-phase immersion-cooling system of claim 35, wherein the pressure-release valve is located within 10 cm of a top edge of the container such that, when the bellows assembly is in use in the two-phase immersion-cooling system, the fifth amount of the gas released from the second volume contains a lower percentage of coolant-liquid vapor from coolant liquid used when the two-phase immersion-cooling system is in operation than if the pressure-release valve were located at a lower elevation on the first wall.

37. The two-phase immersion-cooling system of claim 36, further comprising: a pressure-release valve fluidically coupled to the second volume such that the fifth amount of the gas can be released from the second volume when pressure within the second volume exceeds a threshold value; and a vapor barrier arranged to transmit air to the pressure-release valve and to block passage of coolant-liquid vapor from coolant liquid used when the two-phase immersioncooling system is in operation.

38. The two-phase immersion-cooling system of any one of claims 19 through claim 34, further comprising: an access door on the immersion tank to access an interior region of the immersion tank; and a sensor to detect opening of the access door, wherein the controller is configured to receive a signal from the sensor indicating an opening of the access door and issue a command signal to activate the isolation valve in response to receiving the signal to isolate the headspace in the immersion tank from the second volume.

39. The two-phase immersion-cooling system of any one of claims 19 through 34, wherein the first wall and second wall deform away from and toward each other in directions that are approximately horizontal, when the bellows assembly is in use in the two-phase immersioncooling system.

40. The two-phase immersion-cooling system of any one of claims 19 through 34, wherein the first wall and second wall deform away from and toward each other in directions that are approximately vertical, when the bellows assembly is in use in the two-phase immersioncooling system.

41. The two-phase immersion-cooling system of any one of claims 19 through 34, wherein a thickness of the first wall between 0.1 mm and 3 mm.

42. The two-phase immersion-cooling system of any one of claims 19 through 34, wherein the polymer comprises polyurethane.

43. The two-phase immersion-cooling system of any one of claims 19 through 34, wherein the first wall and the second wall have a same rectangular shape.

44. The two-phase immersion-cooling system of any one of claims 19 through 34, wherein a ratio of the second volume to a volume of the headspace is in a range from 0.4 to 1.5.

45. An immersion-cooling system comprising: an immersion tank to hold at least one computing component immersed in a coolant liquid within the immersion tank; a dehumidifier fluidically coupled to a headspace of the immersion tank, the dehumidifier configured to capture water molecules from a gas mixture in the headspace of the immersion tank; and a gas replacement chamber, fluidically coupled to the immersion tank, configured to supply a first amount of a dry gas to replace the water molecules captured from the gas mixture in the headspace of the immersion tank.

46. The immersion-cooling system of claim 45, wherein the dehumidifier is a compressor dehumidifier.

47. The immersion-cooling system of claim 45, wherein the dehumidifier is a desiccant dehumidifier.

48. The immersion-cooling system of claim 45, further comprising: a collection tank, in fluid communication with the dehumidifier, to collect water from the dehumidifier; and a conduit passing through a wall of the immersion tank to remove water from the collection tank to a region outside the immersion tank.

49. The immersion-cooling system of claim 45, further comprising: a gas sensor disposed in the headspace to detect a non-condensable gas; and a release valve mounted to the immersion tank to release the non-condensable gas from the headspace of the immersion tank in response to detection of an amount of the non- condensable gas at or above a first threshold amount, wherein the gas replacement chamber is further configured to supply a second amount of the dry gas to replace the non-condensable gas released from the headspace of the immersion tank.

50. The immersion-cooling system of claim 49, wherein the non-condensable gas is oxygen.

51. The immersion-cooling system of claim 49, further comprising: a system controller communicatively coupled to the gas sensor and to the release valve, wherein the system controller is configured to open the release valve in response to receiving information from the gas sensor indicating the amount of the non-condensable gas is at or above a first threshold amount.

52. The immersion-cooling system of claim 51, wherein: the gas sensor is further configured to detect a halogen gas, and the system controller is further configured to close the release valve in response to receiving information from the gas sensor indicating an amount of the halogen gas is at or above a second threshold amount.

53. The immersion-cooling system of claim 52, wherein the halogen gas comprises fluorine.

54. The immersion-cooling system of claim 51, further comprising: a flow valve fluidically coupled between the immersion tank and the gas replacement chamber, wherein: the system controller is communicatively coupled to the flow valve, andthe system controller is further configured to open the flow valve to admit the dry gas into the headspace in response to releasing the non-condensable gas from the headspace.

55. The immersion-cooling system of claim 45, wherein the coolant liquid comprises a thermally conductive dielectric coolant liquid.

56. The immersion-cooling system of claim 55, wherein the coolant liquid comprises a fluoroketone.

57. The immersion-cooling system of claim 45, wherein the dry gas comprises at least one of nitrogen or argon.

58. The immersion-cooling system of claim 45, further comprising an auxiliary chamber fluidically coupled to the immersion tank and configured to at least partially fill the immersion tank with the coolant liquid.

59. A method of removing water molecules from a gas mixture in a headspace of an immersion tank, the method comprising: cooling at least one computer component with a coolant liquid in the immersion tank; capturing the water molecules with a dehumidifier that is fluidically coupled to a headspace of the immersion tank; and admitting a first amount of dry gas into the headspace to replace the water molecules captured from the gas mixture, wherein the first amount of dry gas is admitted from a gas replacement chamber that is fluidically coupled to the immersion tank.

60. The method of claim 59, further comprising: collecting water from the dehumidifier into a collection tank that is in fluid communication with the dehumidifier; and removing water from the collection tank to a region outside the immersion tank using a conduit that passes through a wall of the immersion tank.

61. The method of claim 59, further comprising: detecting, with a gas sensor disposed in the headspace, a non-condensable gas in the headspace; and releasing, with a release valve mounted to the immersion tank, the non-condensable gas from the headspace of the immersion tank in response to detecting an amount of the non- condensable gas at or above a first threshold amount, wherein the gas replacement chamberfurther operates to supply a second amount of the dry gas to replace the non-condensable gas released from the headspace of the immersion tank.

62. The method of claim 61, wherein the non-condensable gas is oxygen.

63. The method of claim 61, wherein releasing the non-condensable gas comprises: receiving, by a system controller, information from the gas sensor; determining, by the system controller, that the amount of the non-condensable gas is at or above the first threshold amount based, at least in part, on the information received from the gas sensor; and controlling, by the system controller, the release valve to open in response to determining that the amount of the non-condensable gas is at or above the first threshold amount.

64. The method of claim 63, wherein the gas sensor is further configured to detect a halogen gas, the method further comprising: receiving, by the system controller, information from the gas sensor indicating an amount of the halogen gas in the headspace; determining, by the system controller, that the amount of the halogen gas is at or above a second threshold amount; and controlling, by the system controller, the release valve to close in response to determining that the amount of the halogen gas is at or above the second threshold amount.

65. The method of claim 64, wherein the halogen gas comprises fluorine.

66. The method of claim 63, further comprising: controlling, by the system controller and in response to releasing the non-condensable gas from the headspace, a flow valve to open that is fluidically coupled between the immersion tank and the gas replacement chamber so that the second amount of dry gas is admitted into the immersion tank.

67. A method of filling an immersion tank of an immersion-cooling system with coolant liquid to cool at least one computing component, wherein the immersion-cooling system comprises: the immersion tank, a dehumidifier fluidically coupled to a headspace of the immersion tank, thedehumidifier configured to capture water molecules from a gas mixture in the headspace of the immersion tank, a gas replacement chamber, fluidically coupled to the immersion tank, configured to supply a first amount of a dry gas to replace the water molecules captured from the gas mixture in the headspace of the immersion tank, and an auxiliary chamber fluidically coupled to the immersion tank and configured to at least partially fill the immersion tank with the coolant liquid, the method comprising: prior to filling the immersion tank with the coolant liquid, operating the dehumidifier to capture the water molecules from the gas mixture in at least the headspace of the immersion tank and from components in the immersion tank; supplying at least the first amount of the dry gas into the immersion tank; and after operating the dehumidifier for a period of time, filling the immersion tank with the coolant liquid from the auxiliary chamber.

68. The method of claim 67, further comprising prior to filling the immersion tank with the coolant liquid: detecting, with a gas sensor disposed in the headspace, a non-condensable gas in the headspace; and releasing, with a release valve mounted to the immersion tank, the non-condensable gas from the headspace of the immersion tank in response to detecting an amount of the non- condensable gas at or above a first threshold amount, wherein the gas replacement chamber further operates to supply a second amount of the dry gas to replace the non-condensable gas released from the headspace of the immersion tank.

69. The method of claim 68, wherein the non-condensable gas is oxygen.

70. The method of claim 68, wherein releasing the non-condensable gas comprises: receiving, by a system controller, information from the gas sensor; determining, by the system controller, that the amount of the non-condensable gas is at or above the first threshold amount based, at least in part, on the information received from the gas sensor; and controlling, by the system controller, the release valve to open in response to determining that the amount of the non-condensable gas is at or above the first threshold amount.

71. The method of claim 70, wherein the gas sensor is further configured to detect a halogen gas, the method further comprising: receiving, by the system controller, information from the gas sensor indicating an amount of the halogen gas in the headspace; determining, by the system controller, that the amount of the halogen gas is at or above a second threshold amount; and controlling, by the system controller, the release valve to close in response to determining that the amount of the halogen gas is at or above the second threshold amount.

72. The method of claim 71, wherein the halogen gas comprises fluorine.

73. The method of claim 70, further comprising: controlling, by the system controller and in response to releasing the non-condensable gas from the headspace, a flow valve to open that is fluidically coupled between the immersion tank and the gas replacement chamber so that the second amount of dry gas is admitted into the immersion tank.

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