Patent Description:
In conventional immersion cooling systems, a large percentage of the boiler tank contains cooling fluid that functioning as a heat sink and is not efficiently removing heat from the system through boiling. High costs are associated with obtaining, containing, and maintaining the additional cooling fluid despite the relatively low efficiency of its inclusion in the boiler tank. <CIT> relates to a substrate on which are positioned electronic components to be cooled. <CIT> relates to a cooled electronic module having a casing. <CIT> relates to a circulating path for a coolant formed inside a heat-radiating function equipped lid portion. <CIT> relates to a heat exchange that causes a coolant vaporized in the cooling module mounting board to condense and a coolant circulating pump that sends the coolant after the condensation in the liquid phase to the cooling module mounting board.

According to the invention, there is provided a computer system and a server computer system in accordance with the claims. The dependent claims provide further optional features.

Features and advantages of the disclosure may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. Features of the present disclosure will become more fully apparent from the following description and appended claims or may be learned by the practice of the disclosure as set forth hereinafter.

In order to describe the manner in which the above-recited and other features of the disclosure can be obtained, a more particular description will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. For better understanding, the like elements have been designated by like reference numbers throughout the various accompanying figures. While some of the drawings may be schematic or exaggerated representations of concepts, at least some of the drawings may be drawn to scale. Understanding that the drawings depict some example embodiments, the embodiments will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:.

The present disclosure relates generally to systems and methods for improving the thermal management of high heat-generation components. More particularly, the present disclosure relates to using localized liquid immersion cooling to cool one or more computer components on a substrate within a larger board of a computing device.

Immersion cooling systems surround the heat-generating components in a liquid cooling fluid, which conducts heat from the heat-generating components to cool the heat-generating components. As the cooling fluid absorbs heat from the heat-generating components, the temperature of the cooling fluid increases and the cooling fluid may vaporize, introducing vapor into the liquid of the cooling fluid, which then rises out of the liquid. The vapor, thereby, removes heat from the cooling fluid near the heat-generating components.

Referring now to <FIG>, an immersion cooling system <NUM> according to the present disclosure includes a chamber <NUM> with a cooling fluid <NUM> positioned therein. A condenser <NUM> is positioned at the top of the cooling fluid <NUM> above the liquid cooling fluid <NUM> and in a vapor <NUM> of the cooling fluid <NUM>. The condenser <NUM> cools part of the vapor <NUM> of the cooling fluid <NUM> back into a liquid phase, removing thermal energy from the system and reintroducing the cooling fluid <NUM> into the immersion bath <NUM> of the liquid cooling fluid <NUM>.

In some embodiments, the immersion bath <NUM> of the liquid cooling fluid <NUM> has a plurality of heat-generating components <NUM> positioned in the liquid cooling fluid <NUM>. The liquid cooling fluid <NUM> surrounds the heat-generating components <NUM> and may surround other objects or parts attached to the heat-generating components <NUM>.

As described, conversion of the liquid cooling fluid <NUM> to a vapor phase <NUM> requires the input of thermal energy to overcome the latent heat of vaporization and may be an effective mechanism to increase the thermal capacity of the cooling fluid and remove heat from the heat-generating components <NUM>.

The cooling fluid transitions between a liquid phase and a vapor phase to remove heat from hot or heat-generating components in the chamber. The liquid phase more efficiently receives heat from the components and, upon transition to the vapor phase, the cooling fluid can be cooled and condensed to extract the heat from the cooling fluid before the cooling fluid is returned to the liquid immersion bath at a lower temperature.

In some embodiments, the immersion bath of the liquid cooling fluid <NUM> has a plurality of heat-generating components <NUM> positioned in the liquid cooling fluid <NUM>. The liquid cooling fluid <NUM> surrounds the heat-generating components <NUM> and other objects or parts attached to the heat-generating components <NUM>. In some embodiments, one or more of the heat-generating components <NUM> includes a heat sink or other device attached to the heat-generating component <NUM> to conduct away thermal energy and effectively increase the surface area of the heat-generating component <NUM>.

Because the vapor phase <NUM> rises in the liquid cooling fluid <NUM>, the vapor phase <NUM> can be extracted from the immersion chamber <NUM> in an upper vapor region <NUM> of the chamber <NUM>. A condenser <NUM> cools part of the vapor of the cooling fluid <NUM> back into a liquid phase, removing thermal energy from the system and reintroducing the cooling fluid into the immersion bath <NUM> of the liquid cooling fluid <NUM>. The condenser <NUM> radiates or otherwise dumps the thermal energy from the cooling fluid <NUM> into the ambient environment or into a conduit to carry the thermal energy away from the cooling system <NUM>.

In some embodiments, the cooling fluid receives heat in a cooling volume of cooling fluid immediately surrounding the heat-generating components. The cooling volume is the region of the cooling fluid (including both liquid and vapor phases) that is immediately surrounding the heat-generating components and is responsible for the convective cooling of the heat-generating components. In some embodiments, the cooling volume is the volume of cooling fluid within <NUM> millimeters (mm) of the heat-generating components.

The cooling fluid has a boiling temperature below a critical temperature at which the heat-generating components experience thermal damage. For example, the heat-generating components may be computing components that experience damage above <NUM>° Celsius (C). In some embodiments, the boiling temperature of the cooling fluid is less than a critical temperature of the heat-generating components. In some embodiments, the boiling temperature of the cooling fluid is less than about <NUM>° C. In some embodiments, the boiling temperature of the cooling fluid is less than about <NUM>° C. In some embodiments, the boiling temperature of the cooling fluid is less than about <NUM>° C. In some embodiments, the boiling temperature of the cooling fluid is less than about <NUM>° C. In some embodiments, the boiling temperature of the cooling fluid is at least about <NUM>° C. In some embodiments, the cooling fluid includes water. In some embodiments, the cooling fluid includes glycol. In some embodiments, the cooling fluid includes a combination of water and glycol. In some embodiments, the cooling fluid is an aqueous solution. In some embodiments, the cooling fluid is an electronic liquid, such as FC-<NUM> available from <NUM>, or similar non-conductive fluids. In some embodiments, the heat-generating components, boiler tank surfaces, or other elements of the immersion cooling system positioned in the cooling fluid have nucleation sites on a surface thereof that promote the nucleation of vapor bubbles of the cooling fluid at or below the boiling temperature of the cooling fluid.

Large immersion cooling systems require a portion of the immersion bath volume to be cooling fluid that is outside of the cooling volume and, therefore, inefficiently cooling the heat-generating components. In some embodiments, not all components of the computing device generate enough heat to need immersion cooling to remain in a safe operating temperature range. In some embodiments, a graphical processing unit (GPU) generates more heat than a platen-based storage device, and ambient air cooling is sufficient to cool the storage device but not the GPU.

In some embodiments, a computing device includes a substrate with a heat-generating component located on the substrate. Some heat-generating components may generate more heat than surrounding components on the same board of the computing device, and a local immersion cooling system may be positioned on or around the heat-generating computer component to provide additional cooling without immersing the entire computing device or board of the computing device.

<FIG> is a perspective view of an embodiment of a heat-generating component <NUM> located on a substrate <NUM>. A boiler tank <NUM> is affixed to the substrate <NUM> to enclose the heat-generating component <NUM>. The boiler tank <NUM> contains cooling fluid <NUM> that receives heat from and cools the heat-generating component <NUM>. In some embodiments, the boiler tank <NUM> is connected directly to the substrate <NUM>, such that the substrate contributes to containing the cooling fluid <NUM>.

In some embodiments, a local immersion cooling system allows more efficient cooling of the heat-generating component(s) that generates the greater amount of heat without requiring the cost and complexity of an immersion cooling system that is large enough to support the entire computing device. In some embodiments, a local immersion cooling system allows for more efficient cooling of components with complex topographies to which it is difficult to attach a conventional heat sink. In some embodiments, a local immersion cooling system allows for more efficient cooling of components that are positioned close to one another, to which it is difficult to attach conventional heat sinks due to the close proximity of the components and the volume required by a conventional heat sink.

In some embodiments, the local immersion cooling system includes a boiler tank that is smaller than the board of the computing device. In some embodiments, the boiler tank has a tank area (e.g., a bottom area of the tank) that is approximately the same area as the substrate of the heat-generating computer component. In some embodiments, the tank area is the same area as the substrate of the heat-generating computer component. In some embodiments, the substrate of the heat-generating computer component is the bottom surface of the boiler tank and the boiler tank attaches directly to a perimeter edge of the substrate.

In some embodiments, a multi-chip module (MCM) is located on a substrate, and the substrate for the MCM is affixed to a board for the computing device. A MCM includes a plurality of electronic components on a single substrate to facilitate efficient energy usage and improve communication bandwidth between the components. As used herein, a MCM may be considered a single heat-generating component, according to some embodiments of the present disclosure. In some embodiments, a MCM has a first component with a first height above the substrate and a second component with a different second height above the substrate. For example, the first component is taller than the second component relative to the substrate of the MCM. A conventional heat sink applied to both the first component and second component would, therefore, need to compensate for the differences in height and/or topography of the two components of the MCM. In other examples, a heat transfer element could be positioned between the heat sink and the shorter of the two components. Each interface between materials and each layer of thermal interface material (TIM) increases the thermal resistance and, hence, inefficiency of the thermal management system.

<FIG> is a side view of an embodiment of a computing device board <NUM> with a first heat-generating component <NUM>-<NUM> and a second heat-generating component <NUM>-<NUM> thereon. The first heat-generating component <NUM>-<NUM> has a first height <NUM>-<NUM> and second heat generating component <NUM>-<NUM> has a second height <NUM>-<NUM>. The cooling fluid <NUM> contained in the boiler tank <NUM> flows around the topography of the first heat-generating component <NUM>-<NUM> and second heat-generating component <NUM>-<NUM> irrespective of their relative heights, shapes, geometries, or surface textures. While conventional components have smooth top surfaces facilitate thermal conductivity to a rigid conductive heat sink, immersion cooling systems according to the present disclosure can efficiently cool components with any geometries or combinations of geometries.

In some embodiments according to the present disclosure, an immersion cooling system for a MCM or other plurality of components on a substrate having different heights can limit and/or eliminate intermediate interfaces that reduce the efficiency of the thermal management system. In some embodiments, the first component and the second component are submerged in the liquid cooling fluid with no additional TIM therebetween. The liquid cooling fluid, therefore, provides a more efficient thermal path to remove heat from both the first component and the second component than a conventional heat sink(s) with one or more layers of TIM.

In some embodiments, a first component and a second component are positioned close to one another, and individual conventional heat sinks cannot be positioned on both the first component and the second component without interfering with one another. An immersion cooling system according to some embodiments of the present disclosure submerge the first component and second component in the liquid cooling fluid and the cooling fluid functions as the heat sink to remove heat from the components. Additionally, the first and second components may produce different amounts of heat at difference conditions, and any heat sink affixed to the components must be sufficient to cool the components under a high operating load, even if that operating load is uncommon. <NUM>-phase immersion cooling can provide a more flexible cooling system that adapts to the amount of heat generated by the components.

<FIG> is a top view of an embodiment of a MCM <NUM> on a board <NUM>. The MCM <NUM> has a plurality of heat-generating components <NUM>-<NUM>, <NUM>-<NUM> positioned on a substrate <NUM> with a boiler tank <NUM> affixed to the board <NUM> encompassing the substrate <NUM> and the heat-generating components of the MCM <NUM>. In some embodiments, a first heat-generating component <NUM>-<NUM> and second heat-generating component <NUM>-<NUM> are located adjacent to one another on the substrate <NUM> and would be too close to one another for a conventional rigid or solid heat sink to be affixed to each without interfering with the other heat sink. In some embodiments, a lateral spacing <NUM> between the first heat-generating component <NUM>-<NUM> and second heat-generating component <NUM>-<NUM> is less than <NUM> millimeters. In some embodiments, a lateral spacing <NUM> between the first heat-generating component <NUM>-<NUM> and second heat-generating component <NUM>-<NUM> is less than <NUM> millimeters.

In some embodiments, not all components on a board require an immersion cooling system to maintain the components in a safe operating temperature range. In some embodiments, a board has a plurality of components positioned thereon, and a boiler tank is positioned on the board to surround at least one component of the plurality of components.

<FIG> is a perspective view of a computing device board <NUM> with a plurality of heat generating components <NUM> thereon. A plurality of boiler tanks <NUM> are positioned on the board <NUM>, but only encompass some of the heat-generating components <NUM>. In some embodiments, a MCM is contained within a boiler tank <NUM>, while other components, such as storage devices are located outside of the boiler tanks <NUM>.

Referring now to <FIG>, in some embodiments, the boiler tank <NUM> has a tank length <NUM>, tank width <NUM>, and tank height <NUM> that define a tank volume. The tank length <NUM> and tank width <NUM> define a tank area. In some embodiments, the board <NUM> has a board length <NUM> and board width <NUM> that define a board area. In some embodiments, at least one component encompassed by the boiler tank is built upon a substrate. In some embodiments, the substrate has a similar substrate length and substrate width that define a substrate area.

In some embodiments, the tank area is the same as the board and/or substrate area. In some embodiments, the tank area is at least <NUM>% less than the board and/or substrate area. For example, the tank area is less than <NUM>% of the board and/or substrate area. In some embodiments, the tank area is less than <NUM>% of the board and/or substrate area to allow at least a portion of the components of the board and/or substrate to be positioned outside of the boiler tank.

In some embodiments, a heat-generating component positioned on the board is located on a substrate. In some embodiments, the tank area is no more than <NUM>% of a substrate area of the substrate. In some embodiments, the tank area is substantially equal to the substrate area. In some embodiments, the tank area is less than the substrate area. In some embodiments, the tank area is less than <NUM>% of the substrate area, as there is conventionally a border around the component on the substrate upon which the component is assembled. In some embodiments, the board and/or substrate has holes therein to allow the board and/or substrate to connect to another structure. The tank area may be less than the board area and/or substrate area because the tank is positioned to allow access to the holes of the board and/or substrate.

In some embodiments, at least a portion of the board and/or substrate forms a wall of the boiler tank. Referring again to <FIG>, the boiler tank <NUM> is connected directly to the board <NUM>, sealing an immersion chamber that includes a portion of the board <NUM> as a wall of the chamber. In some embodiments, at least a portion of the board and/or substrate is integral to the boiler tank and holds the cooling fluid in the boiler tank. In some embodiments, the board and/or substrate upon which the boiler tank is positioned has an O-ring <NUM> positioned thereon that facilitates a liquid-tight seal between the board and/or substrate and the boiler tank. In some embodiments, the O-ring <NUM> follows at least a portion of a perimeter edge of the board and/or substrate. In some embodiments, the O-ring <NUM> follows the entire perimeter edge of the board and/or substrate. In some embodiments, the O-ring <NUM> is affixed to the boiler tank <NUM>, such that when the boiler tank <NUM> is placed in contact with the board and/or substrate, the O-ring <NUM> seals the contact area between the boiler tank <NUM> and the board and/or substrate.

The boiler tank according to some embodiments of the present disclosure includes a cooling mechanism to condense vapor cooling fluid to a liquid phase and remove heat from the boiler tank. In some embodiments, the boiler tank includes or is in fluid communication with a condenser. In some embodiments, the condenser is a liquid-cooled condenser that cycles a second fluid (e.g., water) through the condenser to transfer heat from the condenser and cool the cooling fluid. In some embodiments, the condenser is a solid-state condenser, such as a Peltier cooler, that cools and condenses the cooling fluid.

In some embodiments, the condenser is located in the boiler tank. In some embodiments, the condenser is located outside of the boiler tank and is in fluid communication with the immersion chamber of the boiler tank to cool and condense the vapor cooling fluid. In some embodiments, the condenser is located outside of the boiler tank and cools a surface of the boiler tank to cool and condense the vapor cooling fluid.

<FIG> is a perspective view of an embodiment of a board <NUM> with a plurality of heat-generating components <NUM> thereon with a boiler tank <NUM> affixed over the plurality of heat-generating components <NUM>. The boiler tank <NUM> has a condenser <NUM> positioned on a surface thereof, that circulates water through coils to cool and condense the cooling fluid in the boiler tank <NUM>.

In some embodiments, a plurality of boiler tanks is in fluid communication with a single condenser. For example, a condenser may be connected to and in fluid communication with a plurality of boiler tanks on a single board. In some embodiments, a condenser may be connected to and in fluid communication with a plurality of boiler tanks on different boards.

In some embodiments, a board and/or substrate has a plurality of boiler tanks positioned thereon. The boiler tanks are positioned to provide immersion cooling to different components of the board and/or substrate, such as a first boiler tank covering and providing immersion cooling to a MCM and a second boiler tank covering and providing immersion cooling to a network switch. In some embodiments, the plurality of boiler tanks shares cooling fluid between the boiler tanks of the plurality of boiler tanks. In some embodiments, each boiler tank of the plurality of boiler tanks has dedicated cooling fluid that does not mix with another boiler tank.

<FIG> is a perspective view of another embodiment of a board <NUM> with a plurality of boiler tanks <NUM> thereon. Each of the boiler tanks <NUM> encloses at least one heat-generating component <NUM>-<NUM>, <NUM>-<NUM>, and at least two of the plurality of boiler tanks <NUM> are in fluid communication with a condenser <NUM>. The boiler tanks <NUM>-<NUM>, <NUM>-<NUM> that are in fluid communication with the condenser <NUM> share cooling fluid therebetween. In some embodiments, some of the boiler tanks <NUM>-<NUM>, <NUM>-<NUM> are in fluid communication with a condenser <NUM>, and some of the boiler tanks are not.

In some embodiments, a board and/or substrate with a plurality of boiler tanks thereon has a total tank area relative to the board area and/or substrate area. The total tank area is the summation of the tank area of each boiler tank of the plurality of boiler tanks. A computing device with two boiler tanks on a board, where each boiler tank has a tank area that is <NUM>% of the board area, has a total tank area that is <NUM>% of the board area. A MCM assembled on a substrate with two boiler tanks on the substrate, where a first boiler tank has a first tank area that is <NUM>% of the substrate area and a second boiler tank has a second tank area that is <NUM>% of the substrate area, has a total tank area that is <NUM>% of the substrate area. For example, the four boiler tanks of <FIG> have a total tank area of approximately <NUM>% of the board area.

In some embodiments, the total tank area is the same as the board and/or substrate area. In some embodiments, the total tank area is at least <NUM>% less than the board and/or substrate area. For example, the total tank area is less than <NUM>% of the board and/or substrate area. In some embodiments, the total tank area is less than <NUM>% of the board and/or substrate area to allow at least a portion of the components of the board and/or substrate to be positioned outside of the plurality of boiler tanks.

As described herein, some embodiments of immersion cooling systems according to the present disclosure include a condenser with active cooling, such as liquid cooling or solid-state cooling. In some embodiments, an immersion cooling system or a boiler tank of an immersion cooling system uses atmospheric cooling to dissipate heat from the cooling fluid. In some embodiments, the liquid cooling fluid can provide efficient heat transfer from heat-generating components with different or varying topographies, while the cooling fluid itself transfers the heat to fins, heat pipes, vapor chambers, heat sinks, or other passive cooling devices to be cooled by atmospheric cooling.

In some embodiments, the boiler tank of the immersion cooling system has a passive cooling device affixed thereto. In some embodiments, the passive cooling device includes heat fins to conduct heat from the boiler tank and to increase surface area exposure to the ambient air and remove heat from the boiler tank. In some embodiments, the passive cooling device includes a heat pipe or vapor chamber to disperse and/or conduct heat from the boiler tank to another area or to increase surface area exposure to the ambient air and remove heat from the boiler tank. In some embodiments, the passive cooling device is used in conjunction with or in addition to an active cooling device.

<FIG> is a side view of an embodiment of a boiler tank <NUM> according to the present disclosure with a heat pipe <NUM> and heat fins <NUM> positioned on a top surface of the boiler tank <NUM>. In some embodiments, the boiler tank <NUM> has sufficient surface area to allow atmospheric cooling of the vapor phase <NUM> in the heat pipe <NUM> to return the vapor phase <NUM> to the liquid cooling fluid <NUM> around the heat-generating component <NUM>.

In some embodiments, boiling cooling fluid and the associated increase in vapor in the boiler tank increases that vapor pressure in the boiler tank. As the condenser or other cooling device cools the vapor to condense the vapor phase back into the liquid phase, the boiler tank may need to sustain increased vapor pressure without rupturing. In some embodiments, the boiler tank can sustain at least <NUM> atmospheres of internal vapor pressure. In some embodiments, the boiler tank can sustain at least <NUM> atmospheres of internal vapor pressure. In some embodiments, the boiler tank can sustain at least <NUM> atmospheres of internal vapor pressure.

To enhance boiling and facilitate return of the cooling fluid to the boiling surface, some embodiments of boiler tanks according to the present disclosure include wicking or boiling enhancement structures located inside the boiler tank in the immersion chamber. In some embodiments, the wicking structure includes an open lattice structure such as sintered copper powder or wire mesh that can enhance boiling efficiency and drive fluid back to the boiling surface using capillary action. In some embodiments, surface etching or boiling enhancement coatings can be applied to the boiling surface to create nucleation sites that enhance boiling efficiency.

Referring again to <FIG>, in some embodiments, the boiler tank <NUM> includes a wicking structure <NUM>. The wicking structure <NUM> is positioned in the vapor portion <NUM> of the boiler tank <NUM>. The wicking structure <NUM> may increase the condensation rate and provide sites upon which the vapor phase <NUM> can condense and return to the liquid cooling fluid <NUM> more readily.

A conventional immersion cooling system includes a boiler tank containing an immersion chamber and a condenser in the immersion chamber. The immersion chamber contains a cooling fluid that has a liquid cooling fluid and a vapor cooling fluid portion. The liquid cooling fluid creates an immersion bath in which a plurality of heat-generating components is positioned to heat the liquid cooling fluid.

The cooling fluid transitions between a liquid phase and a vapor phase to remove heat from hot or heat-generating components in the chamber. The liquid phase more efficient receives heat from the components and, upon transition to the vapor phase, the cooling fluid can be cooled and condensed to extract the heat from the cooling fluid before the cooling fluid is returned to the liquid immersion bath at a lower temperature.

In some embodiments, the immersion bath of the liquid cooling fluid has a plurality of heat-generating components positioned in the liquid cooling fluid. The liquid cooling fluid surrounds the heat-generating components and other objects or parts attached to the heat-generating components. In some embodiments, one or more of the heat-generating components includes a heat sink or other device attached to the heat-generating component to conduct away thermal energy and effectively increase the surface area of the heat-generating component.

As described, conversion of the liquid cooling fluid to a vapor phase requires the input of thermal energy to overcome the latent heat of vaporization and may be an effective mechanism to increase the thermal capacity of the cooling fluid and remove heat from the heat-generating components. Because the vapor rises in the liquid cooling fluid, the vapor phase can be extracted from the chamber in an upper vapor region of the chamber. A condenser cools part of the vapor of the cooling fluid back into a liquid phase, removing thermal energy from the system and reintroducing the cooling fluid into the immersion bath of the liquid cooling fluid. The condenser radiates or otherwise dumps the thermal energy from the cooling fluid into the ambient environment or into a conduit to carry the thermal energy away from the cooling system.

In some embodiments, a first component and a second component are positioned close to one another, and individual conventional heat sinks cannot be positioned on both the first component and the second component without interfering with one another. In some embodiments, an immersion cooling system according to the present disclosure submerge the first component and second component in the liquid cooling fluid and the cooling fluid functions as the heat sink to remove heat from the components. Additionally, the first and second components may produce different amounts of heat at difference conditions, and any heat sink affixed to the components must be sufficient to cool the components under a high operating load, even if that operating load is rare. <NUM>-phase immersion cooling can provide a more flexible cooling system that adapts to the amount of heat generated by the components.

In some embodiments, not all components on a board require an immersion cooling system to maintain the components in a safe operating temperature range. In some embodiments, a board has a plurality of components positioned thereon, and a boiler tank is positioned on the board to surround at least one component of the plurality of components. In some embodiments, the boiler tank has a tank length, tank width, and tank height that define a tank volume. The tank length and tank width define a tank area. In some embodiments, the board has a board length and board width that define a board area. In some embodiments, at least one component encompassed by the boiler tank is built upon a substrate. In some embodiments, the substrate has a substrate length and substrate width that define a substrate area.

In some embodiments, at least a portion of the board and/or substrate forms a wall of the boiler tank. In some embodiments, at least a portion of the board and/or substrate is integral to the boiler tank and holds the cooling fluid in the boiler tank. In some embodiments, the board and/or substrate upon which the boiler tank is positioned has an O-ring positioned thereon that facilitates a liquid-tight seal between the board and/or substrate and the boiler tank. In some embodiments, the O-ring follows at least a portion of a perimeter edge of the board and/or substrate. In some embodiments, the O-ring follows the entire perimeter edge of the board and/or substrate.

In some embodiments, a board and/or substrate with a plurality of boiler tanks thereon has a total tank area relative to the board area and/or substrate area. The total tank area is the summation of the tank area of each boiler tank of the plurality of boiler tanks. A computing device with two boiler tanks on a board, where each boiler tank has a tank area that is <NUM>% of the board area, has a total tank area that is <NUM>% of the board area. A MCM assembled on a substrate with two boiler tanks on the substrate, where a first boiler tank has a first tank area that is <NUM>% of the substrate area and a second boiler tank has a second tank area that is <NUM>% of the substrate area, has a total tank area that is <NUM>% of the substrate area.

In at least some embodiments of the present disclosure, an immersion cooling system that uses a boiler tank applied to a heat-generating component or a portion of a board of a computing device provides targeting high efficiency cooling to reduce costs and infrastructure limitations associated with large immersion tanks. Immersion cooling systems according to the present disclosure can improve modularity and reduce costs relative to conventional systems.

Claim 1:
A computer system (<NUM>; <NUM>; <NUM>) having thermal management, the system comprising: a boiler tank (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>-<NUM>, <NUM>-<NUM>; <NUM>) having a length (<NUM>), width (<NUM>), and height (<NUM>);
a first computer component (<NUM>; <NUM>-<NUM>; <NUM>; <NUM>; <NUM>-<NUM>, <NUM>-<NUM>; <NUM>) on a substrate (<NUM>; <NUM>; <NUM>) in the boiler tank;
a second computer component (<NUM>-<NUM>; <NUM>; <NUM>; <NUM>-<NUM>, <NUM>-<NUM>) on the substrate in the boiler tank;
a cooling fluid (<NUM>; <NUM>; <NUM>) positioned in the boiler tank and covering the first computer component; and
at least one computer component on the substrate that is not covered by a boiler tank,
wherein the length (<NUM>) and the width (<NUM>) of the boiler tank define a tank area that is no more than <NUM>% of a substrate area;
wherein the boiler tank has nucleation sites on a surface thereof that promote the nucleation of vapor bubbles of the cooling fluid at or below the boiling temperature of the cooling fluid, wherein the nucleation sites comprise surface etching or boiling enhancement coatings.