Cross-Reference to Related Applications

The present application claims the benefit of US Provisional Patent Application 63/412,590 filed October 3, 2022, which is hereby incorporated by reference in its entirety.

Field of the Disclosure

The present application relates to systems and methods for using heat pipes and oscillation to optimize the cooling of immersion devices including but not limited to cooling servers for super computers, cryptocurrency mining, or other purposes, and cooling other devices.

Background of the Disclosure

Immersion cooling is a process for cooling electronic devices and components, such as computers, servers, and batteries by immersing the electronic device in a cooling, dielectric fluid. Heat generated by the electronic device is absorbed by the dielectric fluid contacting the electronic device, and dispersed throughout the dielectric liquid. The dielectric fluid can then be further subjected to further cooling to release the heat from the heated dielectric fluid.

There are two different forms of immersion cooling utilized, single-phase immersion cooling and two-phase immersion cooling. FIG. 1 shows an example of a traditional single phase cooling system of the prior art. In the single-phase system, a rack of servers 10 is sealed in a container 11 that is filled with a dielectric fluid 12 circulating through the container 11. The servers

10 release heat to the dielectric fluid 12. Heated dielectric fluid 13, rises and exits the container

11 and is provided to a coolant distributor 14 having a coolant pump 15. The coolant pump 15 passes the dielectric fluid 13 through a heat exchanger 16 having cool water 17 passing therethrough to absorb heat from the dielectric fluid 13. The cooled dielectric fluid 12 is then pumped back to the container 11 for cooling the rack of servers 10. Heated water 18 from the heat exchanger 16 can be provided to a further heat exchanger 19, to cool the water 18 and recirculate cooled water 17 to the heat exchanger 16.

FIG. 2 shows a traditional two-phase cooling system according to the prior art. In the two- phase system, a rack of servers 20 is sealed in a container 21 that includes a dielectric fluid 22 surrounding the servers 20. The dielectric fluid 22 boils upon contact with the servers 20, which transforms the liquid dielectric fluid 22 into a vapor 23. The vapor 23 rises and contacts a condenser coil 24 having cold water circulating therethrough, and the vapor condenses and drips back into the dielectric fluid 22 cooled. The water 26 that is circulated through the condenser coil 24, after heating, can be provided to a heat exchanger 27 to cool the water 26, which can potentially be recirculated back through the condenser coil 24.

Summary of the Disclosure

The present application relates to an immersion cooling system for servers or other electronic devices that utilize heat pipes spanning separated immersion tanks and cooling tanks to remove heat from the immersion tanks.

Heat pipes are fully sealed, passive two-phase heat transfer devices that take advantage of a fluid’s high heat of vaporization, to achieve extremely efficient heat transfer. A heat pipe comprises an envelope, a wick structure, and a small amount of working fluid. Heat pipes can also have fins for better thermal transfer. The operating fluid of the heat pipe is processed under a vacuum, which allows for two- phase operation across a wide temperature range during operation. External heat is input into what is known as the evaporator of the heat pipe. The heat boils the fluid and pushes the fluid vapor to the colder region of the heat pipe. The colder region, which is typically coupled to a heat sink, is known as the condenser. The operating fluid gives up its latent heat and condenses back to a liquid, and is again absorbed in the wick structure. The wick structure then passively pumps the fluid back to the evaporator.

Additional examples of heat pipes that can be used in connection with the present disclosure can be found in applicant’s US Patent Application 17/607,170 filed October 28, 2021, and US Patent Application 15/516,075 filed March 31, 2017, which are each incorporated by reference in their entireties.

In accordance with a first aspect of the present application, a system is provided. The system comprises: an immersion tank configured to house a dielectric fluid and at least one electronic device; a cooling tank configured to house a cooling fluid and disposed adjacent to the immersion tank, and at least one heat pipe spanning into each of the immersion tank and the cooling tank and configured to absorb heat from the dielectric fluid of the immersion tank and release heat into the cooling fluid of the cooling tank. The cooling tank can be disposed atop the immersion tank. Implementations of the system may further comprise one or more of the following features:

The at least one heat pipe of the system may include a plurality of heat pipes, each heat pipe spanning into each of the immersion tank and the cooling tank and configured to absorb heat from the dielectric fluid of the immersion tank and release heat into the cooling fluid of the immersion tank. The cooling tank of the system further may comprise: a cooling fluid input configured to input chilled cooling fluid into the cooling tank; and a cooling fluid output configured to output heated cooling fluid from the cooling tank. The cooling fluid input may include an oscillating pump configured to inject the chilled cooling fluid into the cooling tank in an oscillating manner. The cooling fluid output may include an oscillating pump configured to output the heated cooling fluid from the cooling tank in an oscillating manner.

The system may further comprise: a geothermal cooling system configured to receive the heated cooling fluid output from the cooling tank, and comprising at least one thermal tank configured to receive the cooling fluid and a coil through which a geothermally cooled fluid passes, thereby cooling the cooling fluid, and configured to output the chilled cooling fluid to the cooling tank.

The system may further comprise: an air cooling system configured to receive the heated cooling fluid output from the cooling tank, and comprising at least one cooling device comprising a coil through which the cooling fluid passes and a fan configured to blow cold air across the coil while the cooling fluid passes through to cool the cooling fluid. The system may further comprise a geothermal cooling system configured to receive the cooling fluid output from the air cooling system, and comprising at least one thermal tank configured to receive the cooling fluid and a coil through which a geothermally cooled fluid passes, thereby cooling the cooling fluid, and configured to output the chilled cooling fluid to the cooling tank.

The immersion tank of the system may comprise at least one oscillating pump therein configured to intake the dielectric fluid from the immersion tank and output the dielectric fluid into the immersion tank in an oscillating manner. The immersion tank may comprise at least one oscillating pump external to the immersion tank configured to intake the dielectric fluid from the immersion tank and output the dielectric fluid into the immersion tank in an oscillating manner.

In accordance with a second aspect of the present application a method is provided, comprising: storing a dielectric fluid and at least one electric device in an immersion tank; storing a cooling fluid in a cooling tank disposed adjacent to the immersion tank; providing at least one heat pipe spanning into each of the immersion tank and the cooling tank; absorbing heat, by an operating fluid of the at least one heat pipe, from the dielectric fluid; and releasing heat, by the operating fluid of the at least one heat pipe, into cooling fluid of the cooling tank. Implementations may further comprise one or more of the following features:

The method may further comprise: inputting chilled cooling fluid into the cooling tank; and outputting heated cooling fluid from the cooling tank. Inputting chilled cooling fluid into the cooling tank further may comprise injecting the chilled cooling fluid into the cooling tank in an oscillating manner. Outputting heated cooling fluid from the cooling tank may further comprise outputting the heated cooling fluid from the cooling tank in an oscillating manner.

The method may comprise outputting the cooling fluid from the air cooling system to a geothermal cooling system; cooling the cooling fluid by the geothermal cooling system by passing the cooling fluid through a thermal tank cooled by a geothermal source; and outputting the chilled cooling fluid to the cooling tank.

The method may comprise outputting the heated cooling fluid from the cooling tank to an air cooling system; and cooling the heated cooling fluid by the air cooling system by providing the cooling fluid through a coil while blowing cold air across the coil by a fan. The method may further comprise outputting the heated cooling fluid from the cooling tank to a geothermal cooling system; cooling the heated cooling fluid by the geothermal cooling system by passing the cooling fluid through a thermal tank cooled by a geothermal source; and outputting the chilled cooling fluid to the cooling tank.

The method may further comprise mixing the dielectric fluid in the immersion tank by an oscillating pump therein configured to intake the dielectric fluid from the immersion tank and output the dielectric fluid into the immersion tank in an oscillating manner. The method may further comprise mixing the dielectric fluid in the immersion tank by an oscillating pump external to the immersion tank configured to intake the dielectric fluid from the immersion tank and output the dielectric fluid into the immersion tank in an oscillating manner.

Brief Description of the Figures

FIG. 1 shows a single phase immersion cooling system of the prior art;

FIG. 2 shows a two-phase immersion cooling system according to the prior art;

FIG. 3 shows an example of a heat pipe used in the immersion cooling system of the present application;

FIG. 4 shows an immersion cooling system of the present application;

FIG. 5 shows a further immersion cooling system of the present application;

FIG. 6 shows a bottom view of the immersion cooling system of FIG. 5;

FIGS. 7a and 7b show an expanded view of a system comprising the immersion cooling system of FIG. 5;

FIG. 8 shows an in-line oscillator installation in accordance with an embodiment of the present application; FIG. 9a shows mixing of fluid in an immersion tank using submersible oscillators according to the present application; and

FIG. 9b shows mixing of fluid in an immersion tank using exterior oscillators according to the present application.

Detailed Description of the Drawings

The immersion cooling systems and methods of the present application will be described with reference made to FIGS. 3 -9b.

FIG. 3 shows an example of a heat pipe 30 that may be used in the present application in connection with an immersion system for cooling one or more devices immersed in a fluid. Fins (not shown) can be added to each end of a heat pipe 30 to improve the thermal transfer. As previously referenced, the heat pipe has a first end 31 serving as an evaporator and a second end 32 serving as a condenser. The heat pipe 30 is self-contained and includes fluids operating in a vacuum. As the temperature rises at the evaporator end 31 of the heat pipe 30, the operating fluid turns to a vapor which absorbs the latent heat. The hot vapor within the heat pipe 30 flows 34 to the cooler condenser end 32 of the heat pipe 30 where it then condenses and releases the latent heat. The condensed fluid then flows 33 back to the evaporator end 31 of the heat pipe 30. The process of the liquid vaporizing and condensing at the two ends 31, 32 of the heat pipe 30 repeats itself. In certain embodiments, the heat pipe 30 can be slanted at an angle to facilitate the condensate returning to the bottom end 31 of the heat pipe 30.

FIG. 4 shows an example of a system of the present application comprising a cooling tank 60 filled with a fluid 65, and an immersion tank 50 filled with a dielectric fluid 55 arranged below the cooling tank 60. The immersion tank 50 houses one or more servers 40, or other electronic devices that require or benefit from regular cooling. One or more heat pipes 30 are provided, which span into and across each of the cooling tank 60 and the immersion tank 50. A plurality of sealed openings may be provided which align in the cooling tank 60 and immersion tank 50 through which the heat pipes 30 are inserted, and where the heat pipes 30 are secured in place.

In accordance with various embodiments of the present application, the dielectric fluid 55 within the immersion tank 50 may be any liquid dielectric or dielectric fluid known in the art suitable for use in such a tank for cooling servers or other electrical equipment, including any dielectric fluids suitable for use in either or both of a single-phase immersion cooler or a two-phase immersion cooler. It is further noted that while servers 40 are the electronic devices referenced in the examples shown in the Figures, other electronic devices could be cooled with this system and that the present application is not limited to use with servers.

The heat pipes 30 operate as described above to cool the immersion tank 50 and the dielectric fluid 55 and servers 40 contained therein by absorbing heat. The condenser ends of the heat pipes 30 are disposed in the cooling tank 60, and the evaporator ends of the heat pipes 30 are disposed in the immersion tank 50. The servers 40 release their heat into the dielectric fluid 55 of the immersion tank 50 that surrounds them. The colder operating fluid in the heat pipe 30 flows towards the immersion tank 50, where it absorbs heat from the dielectric fluid 55 in the immersion tank 50. The heated operating fluid of the heat pipe 30 then travels back towards the cooling tank 60, where it releases heat into the cooling fluid 65 of the cooling tank 60. The cycle in which the heat pipe 30 absorbs heat from the dielectric fluid 55 to cool the immersion tank 50 and releases heat to the cooling tank 60 occurs repetitively. The system may comprise a plurality of heat pipes 30 arranged in rows in between servers 40, as shown for example in FIG. 6, or the heat pipes may be arranged in alternative ways. It is also noted that the present application is not limited to a particular number of heat pipes 30 being used in the system, and it is envisioned that a system can be provided with as few as one heat pipe 30, or can be provided with a many heat pipes 30 depending on the cooling needs of the immersion tank 50.

FIG. 5 shows an immersion cooling system 100, which is a variation on the system shown in FIG. 4. In the immersion cooling system 100, one or more pumping oscillators 90 are provided at the cooling fluid input for inputting the cooling fluid 70 into the cooling tank 60. One or more oscillators 90 may also be provided with the fluid return for outputting heated fluid 80 for cooling. The system 100 of FIG. 5 may further comprise one or more circulating oscillators 90 in or outside of the immersion tank 50, which are configured to circulate the dielectric fluid 55 within the immersion tank 50. FIG. 6 illustrates a bottom view of the system 100 of FIG. 5. FIGS. 7a and 7b illustrate a further detailed view of the system 100 of FIG. 5, including the flow path of the cooling fluid into (fluid 70) the cooling tank 60 and out of (fluid 80) the cooling tank 60.

To aid in facilitating the cooling of the heat pipes 30 in the cooling tank 60, chilled cooling fluid 70, such as water, is pumped to the cooling tank 60. Heated fluid 80 coming out of the cooling tank 60 is circulated to one or both of an air cooling system 110 and a geothermal cooling system 120.

The air cooling system 110 cools the fluid 80, by way of one or more cooling devices 111, 112 comprising fans 113 and air cooling coils 114, as shown in FIG. 7b. Heated fluid 80 from the cooling tank 60 is output and fed into the air cooling coils 114 of the air cooling system 110. Using fans 113, the cooling devices 11 1, 112 blow ambient air 115 through air cooling coils 1 14 containing the circulated fluid until the ambient air provides no additional cooling benefit. In various embodiments of the air cooling system 110, a single cooling device 111 may be provided, or a plurality of air cooling devices 111, 112 can be provided. The heated fluid 80 can be fed directly into multiple air cooling coils 114 of different air cooling devices, or the fluid can be cooled by a first air cooling device 111 and then passed to a second air cooling device 112, as shown in FIG. 7b. Although FIG.7b shows only two cooling devices 111, 112, other embodiments may comprise more than two cooling devices in a plurality of cooling devices.

After cooling by the air cooling system 110, the cooler fluid 75 is then pumped to thermal tanks 121, 122 of one or more geothermal cooling system 120 for further cooling, and the output cold fluid 70 is recirculated and input to the cooling tank 60. The geothermal cooling system 120 receives a cooling input from a geothermal source 130, which is provided to the thermal tank 121 via coils 124. For example, a fluid such as water may be pumped into a geothermal well for cooling and pumped back to the thermal tank for circulating through coils 124. The application is not limited to any geothermal cooling unit but can be geothermal cooling units known in the art, including any of those described in the above-referenced patent applications. In the embodiment shown in FIG. 7b, two thermal tanks 121, 122 are provided, and fluid 125 cooled by the first thermal tank 121 is passedto the second thermal tank 122 for further cooling, before being supplied back to the immersion tank 50. In other embodiments, the fluid 75 output by the air cooling system 110 may be provided directly to multiple thermal tanks 121, 122. Although FIG.7b shows only two thermal tanks 121, 122, other embodiments may comprise more than two thermal tanks in a plurality of thermal tanks, or may comprise only one thermal tank.

After the heated fluid 80 from the cooling tank is cooled by the air cooling system 110 and/or geothermal cooling system 120, the cooling fluid 70 is pumped into the cooling tank 60, where it absorbs heat from the heat pipes 30 as previously described. The heated fluid 80 of the cooling tank 60 is then pumped out of the cooling tank 60 for cooling by the air cooling system 110 and/or geothermal cooling system 120 as previously described. The immersion cooling system 100 of the present application may further comprise oscillators 90 in connection with the immersion tank 50 and/or the cooling tank 60. The principle of the oscillating flow heat transfer is exchanging heat between higher energy portions of the flow with the adjacent, low energy portions of the flow. Oscillating flow heat exchanger performance mainly depends on oscillation frequency, tidal displacement, axial temperature gradient, tube dimension, and fluid properties. The significant enhancement in the performance of an oscillating flow heat exchanger is due to combined effect of increase in periodic lateral heat conduction and longitudinal convection due to flow oscillation in presence of axial temperature gradient. The design of the compact system is possible because of significant enhancement in these performance indicators.

The oscillation control system 91 of the present application uses sensor data 92 to measure performance and temperature of the cooling tank, servers, and immersion tank; adjusts the speed of the oscillator(s) 90 to create frequency mixing modes; converges the operation of one or more oscillators 90 on the frequency combinations that optimize heat transfer; and controls 93 the pumps to optimize flow requirements. Examples of oscillator devices that can be used in connection with the present system include those shown and described in International Application PCT/US22/45009 filed September 28, 2022, which is incorporated by reference in its entirety. Such oscillator devices can be used in combination with a pump for pumping applications that oscillate the pump flow (such as in operation of the cooling tank) and can also be used in applications for circulating or mixing a fluid within a tank or container (such as in the circulation of dielectric fluid in the immersion tank).

FIG. 8 shows a simplified operation of an oscillator 90. A pump 94 is connected to the oscillator 90 by way of a pipe 95a connected to the pump 94 and a port of the oscillator 90. The pump 94 provides fluid 70a from a fluid source, such as the geothermal cooling system 120 and/or the air cooling system 110, to the oscillator 90, and an electric motor 96 rotates an oscillating valve of the oscillator 90 in order to provide a pulsed fluid 70a through a second pipe 95b connected to an outlet port of the oscillator 90. Such an oscillator 90 can be used in pumping chilled cooling fluid 70 into the cooling tank 60.

FIG. 9a shows a side view of a simplified operation of the oscillator 90 in mixing or circulating the dielectric fluid 55 in the immersion tank 50 using one or more interior, submersible oscillators 90. Fluid is circulated throughout the immersion tank 50 using one or more oscillator 90 submerged in the immersion tank 50. The pump of the submersible oscillator 90 can be positioned inside or outside of the immersion tank 50, which is configured to take in dielectric fluid 55 from within the immersion tank 50 via a fluid line 55b and pump the fluid towards the oscillator 90, which reinjects the fluid 55a into the immersion tank 50. The oscillator 90 can be provided with a motor to rotate the oscillating valve within to pulse the fluid 55a into the immersion tank 50. The pulsing of the fluid 55a into the immersion tank 50 causes additional turbulence within the immersion tank 50 to enhance mixing of the fluid therein.

FIG. 9b shows a simplified operation of the oscillator 90 in mixing or circulating the dielectric fluid 55 in the immersion tank 50 using one or more exterior oscillators 90. Fluid is circulated throughout the immersion tank 50 using a one or more oscillators 90 located outside of the immersion tank 50. A pump 97 is positioned inside or outside of the immersion tank 50, which is configured to take in fluid from within the immersion tank 50 via a fluid line and pump the fluid towards the oscillator 90, which reinjects the fluid 55a into the immersion tank 50. The oscillator 90 is provided with a motor 96 to rotate the oscillating valve within to pulse the fluid 55a into the immersion tank 50. The pulsing of the fluid 55a into the immersion tank 50 causes additional turbulence within the immersion tank 50 to enhance mixing of the fluid 55 therein.

Other embodiments and arrangements of the oscillator 90, including those described in PCT/US22/45009, which is incorporated by reference.

It should be understood that, unless stated otherwise herein, any of the features, characteristics, alternatives or modifications described regarding a particular embodiment herein may also be applied, used, or incorporated with any other embodiment described herein. Also, the Figures herein are not drawn to scale. Although the invention has been described and illustrated with respect to exemplary embodiments thereof, the foregoing and various other additions and omissions may be made therein and thereto without departing from the spirit and scope of the present invention.