Apparatus and system for two-phase server cooling using a series condenser unit

Abstract

Embodiments of an information technology (IT) cooling system are disclosed. The system includes an IT container having an internal volume. Within the internal volume is an immersion fluid region adapted to immerse one or more servers in a two-phase immersion fluid. An immersion condenser is located above the immersion fluid region in the internal volume. The design includes a circulation condenser. The circulation condenser is fluidly coupled to a liquid distribution manifold and a vapor return manifold that are located above the immersion tank (i.e., the immersion fluid region) in the internal volume and are adapted to circulate a two-phase circulation fluid. The circulation condenser is also fluidly coupled to the immersion condenser, and an external cooling fluid is pumped from the circulation condenser to the immersion condenser. The distribution manifold is adapted to be fluidly coupled to a server liquid cooling loop.

Description

TECHNICAL FIELD

[0001] The disclosed embodiments relate generally to information technology (IT) liquid cooling systems, but not exclusively to apparatuses and systems for two-phase server cooling using a series condenser unit. BACKGROUND

[0002] Modern data centers, such as cloud computing centers, house a large number of information technology (IT) devices, such as servers, blade servers, routers, edge servers, power supply units (PSUs), battery backup units (BBUs), and the like. These individual IT device pieces are typically housed in racks within the computing center, with multiple IT devices in each rack. Within the data center, the racks are often grouped into clusters.

[0003] As IT device computing power has become more powerful, it has also consumed more power, and thus generated more heat. This heat must be removed from the IT devices to maintain their normal operation. Various cooling solutions have been developed to meet the growing demand for heat removal. One of the solutions is immersion cooling, in which the IT devices themselves are immersed in a cooling fluid. The cooling fluid can be a single-phase or two-phase cooling fluid; in either case, heat from the IT devices is transferred to the cooling fluid in which they are immersed. But existing two-phase immersion cooling systems have only coolant within the IT enclosure, and current two-phase immersion cooling solutions are not adequate to support high-power density servers that include one or more high-power density chips. Such designs are inefficient and would not be a proper solution for large-scale deployments. SUMMARY

[0004] The present application relates to information technology (IT) cooling systems and cooling systems for information technology (IT) enclosures.

[0005] According to an aspect of the present application, an information technology (IT) cooling system includes an IT container defining an interior volume. Within the interior volume are an immersion tank adapted to immerse one or more servers in a two-phase immersion fluid, an immersion condenser located above the immersion tank in the interior volume, the immersion condenser including an external inlet and an external outlet, and a liquid distribution manifold and a vapor return manifold located above the immersion tank in the interior volume and adapted to circulate a two-phase circulation fluid, the liquid distribution manifold being adapted to be fluidly coupled to a liquid inlet of a cooling device that is thermally coupled to a heat-generating electronic component in at least one of the one or more servers, and the vapor return manifold being adapted to be fluidly coupled to a vapor outlet of the cooling device.

[0006] According to another aspect of the present application, a cooling system for an information technology (IT) enclosure includes an IT container defining an interior volume. Within the interior volume is an immersion tank adapted to immerse one or more servers in a two-phase immersion fluid, an immersion condenser located above the immersion tank in the interior volume, the immersion condenser including an external inlet and an external outlet, a liquid distribution manifold and a vapor return manifold located above the immersion tank and adapted to transport a two-phase circulating fluid, the liquid distribution manifold adapted to be fluidly coupled to a liquid inlet of a cooling device that is thermally coupled to a heat generating electronic component in at least one of the one or more servers, and the vapor return manifold adapted to be fluidly coupled to a vapor outlet of the cooling device, and a circulating condenser located above the immersion tank in the interior volume, the circulating condenser fluidly coupled to the liquid distribution manifold and the vapor return manifold, and the circulating condenser having an external outlet and an external inlet, the external outlet coupled to the external inlet of the immersion condenser. BRIEF DESCRIPTION OF DRAWINGS

[0007] Non-limiting and non-exhaustive embodiments of the present application are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views. Unless otherwise indicated, same reference numbers indicate same or similar components.

[0008] Figure 1 is a schematic diagram of an embodiment of an information technology (IT) cooling system.

[0009] Figure 2 is a schematic diagram of another embodiment of an IT cooling system.

[0010] Figure 3 is a schematic diagram of another embodiment of an IT cooling system.

[0011] Figure 4 is a schematic diagram of another embodiment of an IT cooling system. DETAILED DESCRIPTION

[0012] Embodiments of two-phase cooling systems for use with information technology (IT) equipment in a data center or an IT container such as an IT rack are described. Specific details are described to provide an understanding of the embodiments, but the application can be practiced without one or more of the details, or with other methods, components, materials, etc. In some instances, well-known structures, materials, or operations are not shown or described in detail but are nonetheless encompassed within the scope of the application.

[0013] Throughout this specification, reference can be made to "an implementation" or "implementations" meaning that a described feature, structure, or characteristic can be included in at least one of the implementations, and multiple manifestations of the described feature, structure, or characteristic can be included in one or more of the implementations. Additionally, the described features, structures, or characteristics can be combined in any suitable manner in one or more implementations. As used in this application, directional terms, such as "forward," "rear," "top," "bottom," "side," "lateral," "longitudinal," and the like, relate to the orientation of the implementations as they are presented in the figures. Any directional term should not be interpreted as implying a specific orientation in use.

[0014] The disclosed implementations are systems for two-phase cooling of IT components. The disclosed implementations use more than one type of two-phase immersion coolant to address challenges related to high power thermal management and corresponding challenges related to two-phase immersion cooling technology. In addition, the disclosed implementations achieve some or all of the following benefits:

[0015] • Adaptation to different IT enclosures and different deployment scales.

[0016] • Different data center architectures, both brownfield and greenfield.

[0017] • Adjustable for different power densities.

[0018] • High efficiency.

[0019] • High accuracy of control.

[0020] • Adaptation to different redundancy needs.

[0021] • Easy to design and implement.

[0022] • Ability to design systems with at least two immersion coolants with different boiling temperatures.

[0023] • More advanced two-phase thermal fluid management.

[0024] The implementations are cooling systems that use two or more two-phase cooling fluids with different boiling temperatures to more effectively extract heat loads from high power density components and address challenges in designing cooling systems using two-phase coolants.

[0025] The embodiments include a pair of two-phase cooling loops. The first two-phase cooling loop is a two-phase immersion system in which all servers and electronic equipment are immersed in the liquid phase of a two-phase immersion fluid. The gas phase of the immersion coolant is cooled by an immersion condenser. The second two-phase cooling loop uses a two-phase circulating fluid that is different from the two-phase immersion fluid. The liquid phase of the circulating fluid is circulated through a cooling device that is thermally coupled to the heat load where it is converted to a gas phase. The resulting gas phase is cooled by a circulating condenser. The immersion condenser and the circulating condenser are connected in series in one cooling fluid loop. In one embodiment, the two-phase circulating loop is a pumped two-phase loop; but in other embodiments, the two-phase circulating loop uses gravity to drive the liquid phase flow.

[0026] Figure 1 An embodiment of an information technology (IT) cooling system 100 is shown. The cooling system 100 combines immersion cooling with localized fluid circulation to cool heat generating electronic components. Immersion cooling is achieved using a two-phase immersion fluid I having a liquid phase IL and a gas phase IV, while circulation cooling is achieved using a two-phase circulating fluid C having a liquid phase CL and a gas phase CV. In most embodiments, the immersion cooling fluid I will be a dielectric fluid, meaning that it has little or no electrical conductivity. In one embodiment, the immersion cooling fluid I and the circulating cooling fluid C are different two-phase fluids; depending on the application, the immersion cooling fluid I and the circulating cooling fluid C will have different boiling points in various embodiments. In embodiments where the circulating fluid C must extract more heat than the immersion fluid I, the circulating fluid C will have a lower boiling point, enabling it to absorb and carry away more heat. A third cooling fluid, an external cooling fluid E, can be used to enhance or speed up the transition of the two-phase cooling fluids I and C from gas phase to liquid phase. The system is designed to minimize or prevent mixing of the immersion fluid (I), the circulating fluid (C), and the external fluid (E).

[0027] The cooling system 100 includes an information technology (IT) container 102 that defines an interior volume. An immersion tank 104 in the interior volume is adapted to contain the liquid phase IL of the two-phase immersion cooling fluid I. In the illustrated embodiment, the immersion tank 104 is part of the IT container and is formed by the lower portion of the interior volume of the IT container 202; but in other embodiments, the immersion tank 104 can be a physically separate tank within the IT container 102. The IT container 102 is sealed to reduce or prevent escape of the liquid phase IL as well as escape of the gas phase IV during operation. The immersion tank 104 can be understood as the immersion fluid region in this design, as further described below, i.e., the region in which servers are immersed and submerged in the two-phase immersion fluid I for cooling.

[0028] In the illustrated embodiment, one or more servers S are located within the IT container 102. The illustrated embodiment includes one server S, but other embodiments can have more servers than illustrated. Within each server S is one or more heat-generating electronic components 106, and a cooling device 108 is thermally coupled to the heat-generating electronic components. In one embodiment, the cooling device 108, which can be an evaporator, has a liquid inlet 110 and a vapor outlet 112. The servers S are immersed in the liquid phase IL, and to ensure immersion cooling of the servers, the amount or level of the liquid phase IL in the immersion tank 104 is set so that the one or more servers S are always fully submerged in the liquid phase.

[0029] In addition to the immersion tank 104, there are three main components in the interior volume of the IT container 102 above the immersion tank 104: an immersion condenser 114, a liquid supply manifold 116, and a vapor return manifold 118. The immersion condenser 114 is not coupled to other components within the IT container 102 by a physical fluid connection. The liquid supply manifold 116 is fluidly coupled to the inlet 110 of the cooling device 108 by a liquid line 120, and the vapor return manifold 118 is fluidly coupled to the vapor outlet 112 by a vapor return line 122. As described below, the cooling device 108, the liquid supply manifold 116, and the vapor return manifold 118 form part of a two-phase circulation cooling loop to provide localized two-phase cooling to the heat-generating components 106.

[0030] Several external components outside the IT container 102 are fluidly coupled to components within the IT container 102 to assist in their performance of their functions. A circulation condenser 124 is fluidly coupled to the liquid supply manifold 116 by a liquid supply line CI and to the vapor return manifold 118 by a vapor return line C2, such that the liquid phase CL flows through CI and the vapor phase CV flows through C2. A pump P2 is fluidly coupled into the liquid supply line CI to increase the pressure and / or flow rate of the liquid phase CL flowing into and through the liquid supply manifold 116.

[0031] The cooling unit 126 is fluidically coupled to both the immersion condenser 114 and the circulation condenser 124. The cooling unit 126 circulates the external cooling fluid E through both condensers, improving its ability to condense the respective two-phase fluids. To circulate the external cooling fluid E through both condensers, the external outlet 114o of the immersion condenser 114 is fluidically coupled to the inlet 126i of the cooling unit 126 through fluid line E1, and the external outlet 126o of the cooling unit 126 is fluidically coupled to the external inlet 124i of the circulation condenser 124 through fluid line E2. A pump P1 is coupled into fluid line E2 to force the external cooling fluid E into the circulation condenser 124. Finally, the external outlet 124o of the circulation condenser 124 is then coupled to the external inlet 114i of the immersion condenser 114 through fluid line E3. With respect to the loop of cooling fluid E, the circulation condenser and the immersion condenser are in series. In other embodiments, the pump P1 can instead be coupled into fluid line E3 or fluid line E1.

[0032] During operation of the cooling system 100, the heat generating components within the server S are cooled by both the immersion cooling loop and the circulation cooling loop. In the immersion cooling loop, heat generated by the heat generating components 106 within the server S is transferred to the liquid phase IL of the immersion fluid I, which is converted to the gas phase IV through evaporation. The gas phase IV rises to the space between the surface of the liquid phase IL in the immersion tank 104 and the top of the IT container 202, where the gas phase IV enters the immersion condenser 114 and condenses back to the liquid phase IL. As described above, the external cooling E from the cooling unit 126 flows into and out of the immersion condenser 114 to improve the condensation rate of the immersion condenser 114. Under the action of gravity, the liquid phase IL falls back into the immersion tank 104 from the immersion condenser 114, where the liquid phase IL will be converted to the gas phase IV again by heat from the components, completing the immersion cooling loop.

[0033] The recirculation cooling loop operates simultaneously with the immersion cooling loop to provide enhanced and more localized cooling to the heat generating components 106. The liquid phase CL of the recirculation cooling fluid C flows from the liquid supply manifold 116 through the liquid supply line 120 and the liquid inlet 110 into the cooling device 108, where the liquid phase CL absorbs heat from the heat generating device 106 and transforms into the vapor phase CV. The vapor phase CV then flows out of the cooling device 108 through the vapor outlet 112 and the vapor line 122 to the vapor return manifold 118. The vapor phase CV then flows from the vapor return manifold 118 through the vapor line C2 into the recirculation condenser 124. In the recirculation condenser 124, the vapor phase CV is condensed back into the liquid phase CL with the aid of the external cooling fluid E from the cooling unit 126. The liquid phase CL is then returned from the recirculation condenser to the liquid supply manifold 116 with the aid of the pump P2 through the liquid supply line C1, completing the recirculation cooling loop. The immersion cooling loop and the recirculation cooling loop are completely separate and operate independently without mixing the respective two-phase fluids. The recirculation loop is the primary cooling system in the system 100 because it functions as a localized high power density thermal management system in a fully two-phase immersion environment. For this reason, the external cooling fluid E is first delivered to the recirculation condenser through the fluid line E2 and then to the immersion condenser through the fluid line E3.

[0034] Figure 2 An embodiment of an information technology (IT) cooling system 200 is shown. The cooling system 200 is similar to the cooling system 100 in most respects. The main difference between the cooling system 100 and the cooling system 200 is that the elements are combined and packaged differently in the cooling system 200 such that the system is modular.

[0035] In the system 200, the IT container 202 has an internal volume, and all the same elements within the internal volume of the IT container 102 can also be found in the IT container 202: the immersion tank 104, the servers S, the immersion condenser 114, the liquid supply manifold 116, and the vapor return manifold 118. All of these components are positioned in the same way and have the same fluid connections between themselves as they do in the IT container 102. But unlike the IT container 102, the IT container 202 has the pump P2 located in the internal volume instead of outside the IT container.

[0036] In the system 200, the elements outside the IT container (primarily the recirculation condenser 124 and the cooling unit 126) are combined and packaged differently than in the system 100. The cooling unit 126 remains as a standalone unit, but the recirculation condenser 124, the pump PI, and portions of the fluid lines between the elements are combined together and packaged in the condenser unit 204. In the embodiment shown, portions of the fluid lines El, E2, and E3 are combined and packaged within the condenser unit 204.

[0037] The fluid connections between the cooling unit 126 and the recirculating condenser 124 and the pump PI in the condenser unit 204, as well as the fluid connections between the cooling unit 126 and the elements within the IT container 202, are substantially the same as in the system 100. The recirculating condenser 124 is fluidly coupled to the liquid supply manifold 116 through a liquid supply line CI and to the vapor return manifold 118 through a vapor return line C2, with the liquid phase CL flowing through CI and the vapor phase CV flowing through C2. A pump P2 is fluidly coupled into the liquid supply line CI to increase the pressure and / or flow rate of the fluid liquid phase CL flowing into and through the liquid supply manifold 116. To circulate the external cooling fluid E through both condensers, the external outlet 114o of the immersion condenser 114 is fluidly coupled to the inlet 126i of the cooling unit 126 through a fluid line E1; the external outlet 126o of the cooling unit 126 is fluidly coupled to the external inlet 124i of the recirculating condenser 124 through a fluid line E2. A pump PI is coupled into the fluid line E2 to cause the external cooling fluid E to flow into the recirculating condenser 124. The external outlet 124o of the recirculating condenser 124 is then coupled to the external inlet 114i of the immersion condenser 114.

[0038] To support the modularity of the components in the system 200, some or all of the IT container 202, the condenser unit 204, and the cooling unit 126 include fluid interfaces to allow one unit to be quickly and efficiently fluidly coupled to another unit. The system 200 includes six fluid interfaces, but other embodiments can include more or fewer fluid interfaces than shown. In the system 200, fluid interface #1 through fluid interface #4 couple elements within the condenser unit 204 to elements within the IT container 202, while fluid interface #5 and fluid interface #6 couple elements within the condenser unit 204 to the cooling unit 126. The fluid interfaces are as follows:

[0039] • Both fluid interface #1 and fluid interface #5 are fluidly coupled in the fluid line E1 between the external outlet 114o of the immersion condenser unit 114 and the external inlet 126i of the cooling unit. Fluid interface #1 is located in the fluid line E1 between the IT container 202 and the condenser unit 204, while fluid interface #5 is located in the fluid line E1 between the condenser unit 204 and the inlet 126i of the cooling unit.

[0040] • Fluid interface #2 is fluidly coupled in the fluid line E3 between the external outlet 124o of the recirculating condenser 124 and the external inlet 114i of the immersion condenser 114. Fluid interface #2 is located in the line E3 between the condenser unit 204 and the IT container 202.

[0041] • Fluidic interface #3 is fluidically coupled in fluid line CI between the recirculation condenser 124 and pump P2 and the liquid supply manifold 116. Fluidic interface #3 is located in line CI between the condenser unit 204 and the IT container 202.

[0042] • Fluidic interface #4 is fluidically coupled in fluid line C2 between the vapor return manifold 118 and the recirculation condenser 124. Fluidic interface #4 is located in line C2 between the condenser unit 204 and the IT container 202.

[0043] In one embodiment, the fluidic interfaces can be quick connect / disconnect fluid connectors; but in other embodiments, the fluidic interfaces can be another type of fluid connector, such as a blind mate connector. In one embodiment, all of the fluidic interfaces can be the same type; but in other embodiments, the fluidic interfaces do not have to be the same type. Even though each fluidic interface is referred to in the singular, each fluidic interface can include one or more fluid connectors. For example, in one embodiment, fluidic interface #3 and fluidic interface #4 can include a single connector between the IT container 202 and the condenser unit 204; but in another embodiment, these same fluidic interfaces can include multiple fluid connectors - for example, one fluid connector at the IT container 202 and another fluid connector at the condenser unit 204.

[0044] The system 200 operates in substantially the same manner as the system 100 described above, with some additional controls. The system 200 includes a pressure sensor PS located in the vapor return manifold 118 and communicatively coupled to the pumps PI and P2. With this arrangement, the amount of cooling fluid E delivered from the cooling unit 126 to the recirculation condenser 124, and the amount of liquid phase CL delivered from the recirculation condenser 124 to the liquid supply manifold 116, can be controlled based on the vapor pressure in the vapor return manifold 118. In one embodiment, for example, if the vapor pressure measured by the pressure sensor PS increases, which means that more liquid is needed at the cooling device 108, then the speed of both pumps PI and P2 can be increased to provide more and colder liquid phase CL to the liquid supply manifold 116 and the cooling device 108. The pressure sensor PS and its communicative coupling to the pumps PI and P2 can also be added to the system 100, in which case the systems 100 and 200 operate in substantially the same manner. Since the recirculation loop functions as a local high power density thermal management system in a fully two-phase immersion environment, the recirculation loop is the primary cooling system in the system 200. The primary cooling system can also be understood as the system that extracts the large amount of heat generated by the server. To this end, the external cooling fluid E is first delivered through fluid line E2 to the recirculation condenser and then through fluid line E3 to the immersion condenser.

[0045] Figure 3Another embodiment of a two-phase cooling system 300 is shown. System 300 is similar in many respects to system 100; the main differences are in the arrangement of some components and the operation of the system. Like cooling system 100, cooling system 300 combines global immersion cooling with local fluid circulation to cool heat-generating electronic components. Immersion cooling is achieved using a two-phase immersion fluid I having a liquid phase IL and a vapor phase IV, while circulation cooling is achieved using a two-phase circulation fluid C having a liquid phase CL and a vapor phase CV. Typically, immersion cooling fluid I will be a dielectric fluid, meaning that it has little or no electrical conductivity. In one embodiment, immersion cooling fluid I and circulation cooling fluid C are different two-phase fluids. In some embodiments, circulation fluid C will have a lower boiling point than immersion cooling fluid I, enabling it to absorb and carry away more heat. A third cooling fluid, an external cooling fluid E, can be used to enhance the transition of cooling fluids I and C from vapor to liquid phase. The system is designed to minimize or prevent mixing of fluids I, C, and E.

[0046] Cooling system 300 includes an information technology (IT) container 302 having an interior volume that includes an immersion tank 104 suitable for containing a liquid phase IL of a two-phase immersion cooling fluid I. In the illustrated embodiment, immersion tank 104 is formed by a lower portion of the interior volume of IT container 202; but in other embodiments, immersion tank 104 can be a physically separate tank within IT container 102. IT container 102 is sealed to reduce or prevent escape of liquid phase IL as well as escape of vapor phase IV during operation.

[0047] In the illustrated embodiment, one or more servers S are located within IT container 302. The illustrated embodiment includes one server S, but other embodiments can have more servers than shown. Within server S are one or more heat-generating electronic components 106, and a cooling device 108 is thermally coupled to the heat-generating electronic components. In one embodiment, cooling device 108, which can be an evaporator, has a liquid inlet 110 and a vapor outlet 112. Server S is immersed in liquid phase IL, and to ensure immersion cooling, the amount or level of liquid phase IL in immersion tank 104 is selected so that one or more servers S remain fully submerged in the liquid phase at all times.

[0048] Within the internal volume of the IT container 302, in addition to the immersion tank 104, four main components are located above the tank: the immersion condenser 114, the recirculation condenser 124, the liquid supply manifold 116, and the vapor return manifold 118. In system 100, the recirculation condenser 124 is located outside the IT container, as opposed to system 300, where the recirculation condenser 124 is located inside the IT container. Within the IT container 302, the immersion condenser 114 has an external inlet 114i that is fluidically coupled to an external outlet 124o of the recirculation condenser 124 by a physical fluidic connection E3. The liquid supply manifold 116 is fluidically coupled to the recirculation condenser 124 by a liquid line CI, and the vapor return manifold 118 is also fluidically coupled to the recirculation condenser by a vapor line C2, where the liquid phase CL flows through CI and the vapor phase CV flows through C2. The liquid supply manifold 116 is also fluidically coupled to the inlet 110 of the cooling device 108 by a liquid line 120, and a vapor return line 122 is fluidically coupled between the vapor outlet 112 and the vapor return manifold 118. As described below, the cooling device 108, the liquid supply manifold 116, the vapor return manifold 118, and the recirculation condenser 124 form part of a two-phase recirculation cooling loop to provide localized two-phase cooling to the heat generating component 106.

[0049] An external cooling unit 126, separate from the IT container 302, is fluidically coupled to both the immersion condenser 114 and the recirculation condenser 124 to circulate an external cooling fluid E through both condensers, improving its ability to condense the respective two-phase fluids. The external outlet 114o of the immersion condenser 114 is fluidically coupled to the inlet 126i of the cooling unit 126 by a fluid line El, and the outlet 126o of the cooling unit 126 is fluidically coupled to the external inlet 124i of the recirculation condenser 124 by a fluid line E2. As described above, the immersion condenser 114 has an external inlet 114i that is fluidically coupled to the external outlet 124o of the recirculation condenser 124 by a fluidic connection E3, such that fluid lines El-E3 form a loop through which fluid E flows. A pump PI is coupled into fluid line E2 to increase the pressure and / or flow rate of the cooling fluid E flowing into and through the recirculation condenser 124 and the immersion condenser 114. In other embodiments, PI can instead be coupled into fluid line E3 or fluid line El.

[0050] As in system 200, system 300 includes fluidic interfaces to facilitate modularity. System 300 includes two fluidic interfaces, but other embodiments can include more or fewer interfaces than shown. Fluidic interface #1 and fluidic interface #2 are used to couple the cooling unit 126 to the immersion condenser and the recirculation condenser within the IT container 302. The fluidic interfaces are as follows:

[0051] • Fluid interface #1 is fluidly coupled in fluid line El between an external outlet 114o of the immersion condenser unit 114 and an external inlet 126i of the cooling unit. Fluid interface #1 is located in fluid line El between the IT container 302 and the cooling unit 126.

[0052] • Fluid interface #2 is fluidly coupled in fluid line E2 between an external outlet 126o of the cooling unit and an external inlet 124i of the circulation condenser 124. Fluid interface #2 is located in line E2 downstream of the pump PI between the cooling unit 126 and the IT container 302.

[0053] During operation of the cooling system 300, the heat generating components within the server S are cooled by both the immersion cooling loop and the circulation cooling loop. In the immersion cooling loop, heat generated by the heat generating components 106 within the server S can be transferred to the liquid phase IL of the immersion fluid I, which is converted into the gas phase IV by evaporation. The gas phase IV rises into the space between the surface of the liquid phase IL in the immersion tank 104 and the top of the IT container 202, where the gas phase IV enters the immersion condenser 114 and condenses back to the liquid phase IL. As described above, the external cooling fluid E from the cooling unit 126 flows through the immersion condenser 114 to increase its condensation rate. By the action of gravity, the liquid phase IL falls back from the immersion condenser 114 into the immersion tank 104, where the liquid phase IL will be converted into the gas phase IV again by heating, completing the immersion cooling loop.

[0054] The circulation cooling loop works simultaneously with the immersion cooling loop to provide enhanced and more localized cooling to the heat generating components 106. The liquid phase CL of the circulation cooling fluid C flows from the liquid supply manifold 116 through the liquid supply line 120 and the liquid inlet 110 into the cooling device 108. In the cooling device 108, the liquid phase CL absorbs heat from the heat generating device 106 and is converted into the gas phase CV. The gas phase CV then flows out of the cooling device 108 through the vapor outlet 112 and the vapor line 122 to the vapor return manifold 118. The gas phase CV then flows from the vapor return manifold 118 through the vapor line C2 into the circulation condenser 124. In the circulation condenser 124, the gas phase CV is condensed back to the liquid phase CL with the help of the external cooling fluid E from the cooling unit 126. The liquid phase CL then returns from the circulation condenser by the action of gravity to supply the supply manifold 116 with liquid through the liquid supply line Cl, completing the circulation cooling loop. Thus, in the system 300, the gas phases CV and IV naturally rise to the condensers in their respective corresponding cooling loops, and the liquid phases IL and CL respectively fall by gravity to the tank and the liquid supply manifold.

[0055] Because the circulation loop is used as a local high power density thermal management system in a fully two-phase immersion environment, the circulation loop is the primary cooling system in system 300. To this end, the external cooling fluid E is first delivered through fluid line E2 to the circulation condenser, and then through fluid line E3 to the immersion condenser.

[0056] Figure 4 Another embodiment of a two-phase cooling system 400 is shown. Cooling system 400 is similar to cooling system 300 in most respects. System 400 includes IT container 302 and cooling unit 126; both include the same components as in system 300, with the components within IT container 302 and cooling unit 126 fluidly connected in the same manner. The primary difference between system 300 and system 400 is that system 400 includes additional fluid and control components for managing system operation. Operation of system 400 is then similar to system 300, but with the additional controls.

[0057] System 400 includes a pair of reservoirs to aid in managing the liquid phases of the immersion and circulation fluids. Circulation reservoir 402 holds the liquid phase CL of circulation fluid C and is fluidly coupled to liquid supply manifold 116 through fluid line C3. Pump P2 is coupled into fluid line C3, and control valve VI is coupled into fluid line C3 downstream of pump P2. Similarly, immersion reservoir 404 holds the liquid phase IL of immersion fluid I and is fluidly coupled to immersion tank 104 through fluid line II. Pump P3 is coupled into fluid line II, and control valve V2 is coupled into fluid line II downstream of pump P3. In other embodiments, circulation reservoir 402 and immersion reservoir 404 can be fluidly coupled to more than one IT container at a time, such that pumps P2 and P3 are also shared by more than one IT container.

[0058] Pressure sensor PS is located in vapor return manifold 118 and is communicatively coupled to pump PI and control valve VI, such that the amount of circulation fluid flowing through the circulation loop can be controlled by controlling the pump speed and the valve opening. The opening of control valve VI is a measure of the valve opening. In one embodiment, the opening can have any value between 0 and 1 : an opening of 0 means the valve is fully closed and all flow is shut off; an opening of 1 means the valve is fully open and fluid flows freely; an opening of 0.5 means the valve is half open, etc.

[0059] In operation, if the vapor pressure measured by the pressure sensor PS drops, it means that more liquid phase CL is needed at the cooling device 108, both the speed of the pump P2 and the opening of the control valve Vl can be increased. The increase in pump speed and valve opening causes the fluid liquid phase CL to be delivered from the circulation reservoir into the liquid supply manifold 116 at a higher pressure and flow rate, thereby delivering more liquid phase to the cooling device 108. In other words, the pump P2 and the control valve Vl are used in combination to replenish the circulation loss flowing through the fluid lines C2 and C2. In other embodiments, the circulation reservoir 402 can be fluidically coupled to multiple IT containers 302, and a separate control valve Vl for each IT container can provide individual control for that particular container.

[0060] The IT container 302 is not completely sealed to prevent the egress of the vapor phase IV, and therefore the amount of liquid phase IL in the immersion tank 104 naturally decreases over time and must be replenished from time to time. To accomplish this replenishment, a liquid level sensor L is located in the immersion tank 104 and is communicatively coupled to the control valve V2, such that the amount of immersion fluid in the immersion tank 104 can be kept high enough to keep one or more servers S fully immersed in the liquid phase IL of the immersion fluid at all times. The liquid level sensor L can be used to control the opening of the control valve V2. If the liquid level of the liquid IL in the immersion tank 104 drops below a desired level, the opening of the control valve V2 is increased, allowing the liquid IL to flow into the immersion tank 104 until the desired level is restored. Once the desired level is restored, the opening of the control valve V2 is decreased to slow or stop the flow of liquid IL into the tank. In other words, the pump P3 and the control valve V2 are used in combination to replenish the liquid phase IL that is lost in the tank 104. In other embodiments, the immersion container 404 can be fluidically coupled to multiple IT containers 302, and a separate control valve V2 for each IT container can provide individual control for that particular IT container.

[0061] Since the circulation loop is used as a local high power density thermal management system in a fully two-phase immersion environment, the circulation loop is the primary cooling system in the system 400. To this end, the external cooling fluid E is first delivered to the circulation condenser through the fluid line E2, and then to the immersion condenser through the fluid line E3. In other embodiments, the control sensor can include more advanced ML algorithms to enhance performance in different scenarios.

[0062] In addition to the embodiments described above, other embodiments are possible. For example:

[0063] • More advanced control and optimization algorithms can be integrated.

[0064] • The IT containers can be designed in different configurations.

[0065] • The solution can be extended to more than two different types of two-phase immersion cooling fluids coexisting in one system.

[0066] The above description of implementations is not intended to be exhaustive or to limit the application to the forms described. Although specific implementations and examples are described herein, various modifications can be made to the implementations and examples.

Claims

1. An information technology cooling system, comprising: An information technology container defining an internal volume, wherein the internal volume has: An immersion tank suitable for immersing one or more servers in a two-phase immersion fluid. An immersion condenser, located above the immersion tank within the internal volume, includes an external inlet and an external outlet. A liquid distribution manifold and a vapor return manifold are located above the immersion tank in the internal volume and adapted to circulate a two-phase circulating fluid. The liquid distribution manifold is adapted to be fluidly connected to the liquid inlet of a cooling device, the cooling device being thermally connected to a heat-generating electronic component in at least one of the one or more servers, and the vapor return manifold is adapted to be fluidly connected to the vapor outlet of the cooling device. A circulating condenser, located outside the information technology container and fluidly connected to the liquid distribution manifold and the vapor return manifold, includes an external inlet and an external outlet, with the external outlet of the circulating condenser fluidly connected to the external inlet of the immersion condenser; as well as An external cooling unit is fluidly connected to the external outlet of the immersion condenser and the external inlet of the circulating condenser to form an external cooling loop. The external cooling unit is adapted to circulate external cooling fluid through the immersion condenser and the circulating condenser.

2. The information technology cooling system according to claim 1, wherein, The external cooling unit has an inlet and an outlet. The inlet of the external cooling unit is fluidly connected to the external outlet of the immersion condenser, and the outlet of the external cooling unit is fluidly connected to the external inlet of the circulating condenser.

3. The information technology cooling system of claim 2 further includes a first pump fluidly connected in the external cooling circuit for recirculating the external cooling fluid between the external cooling unit, the immersion condenser and the circulating condenser.

4. The information technology cooling system according to claim 3, wherein, At least a portion of the fluid connection between the circulating condenser, the first pump, and the external outlet of the immersion condenser and the inlet of the external cooling unit is encapsulated together in a condenser unit outside the information technology container.

5. The information technology cooling system according to claim 4, wherein, The information technology container and the condenser unit include a fluid connection interface, through which the external cooling unit and the circulating condenser are fluidly connected to the immersion condenser, and the circulating condenser is fluidly connected to the liquid distribution manifold and the vapor return manifold via the fluid connection interface.

6. The information technology cooling system of claim 3 further includes a second pump connected between the circulating condenser and the liquid distribution manifold.

7. The information technology cooling system according to claim 6, wherein, The second pump is encapsulated within the information technology container.

8. The information technology cooling system of claim 3 further includes a pressure sensor located in the steam return manifold, the pressure sensor being communicatively connected to the first pump.

9. The information technology cooling system according to claim 1, wherein, The two-phase immersion fluid and the two-phase circulating fluid are different two-phase fluids.

10. A cooling system for an information technology enclosure, the cooling system comprising: An information technology container defining an internal volume, wherein the internal volume has: An immersion tank suitable for immersing one or more servers in a two-phase immersion fluid. An immersion condenser is located above the immersion tank within the internal volume, and the immersion condenser includes an external inlet and an external outlet. A liquid distribution manifold and a vapor return manifold, located above the immersion tank and adapted to deliver a two-phase circulating fluid, the liquid distribution manifold being fluidly connected to the liquid inlet of a cooling unit thermally connected to a heat-generating electronic component in at least one of the one or more servers, and the vapor return manifold being fluidly connected to the vapor outlet of the cooling unit. A circulating condenser is located above the immersion tank in the internal volume, the circulating condenser is fluidly connected to the liquid distribution manifold and the vapor return manifold, and the circulating condenser has an external outlet and an external inlet, the external outlet of the circulating condenser being connected to the external inlet of the immersion condenser; as well as An external cooling unit is fluidly connected to the external outlet of the immersion condenser and the external inlet of the circulating condenser to form an external cooling loop. The external cooling unit is adapted to circulate external cooling fluid through the immersion condenser and the circulating condenser.

11. The cooling system of claim 10, further comprising a first pump fluidly connected to the external cooling circuit to recirculate the external cooling fluid between the external cooling unit, the immersion condenser, and the circulating condenser.

12. The cooling system according to claim 11, wherein, The external cooling unit includes a fluid connection interface, through which the external cooling unit is fluidly connected to the external outlet of the immersion condenser and the external inlet of the circulating condenser.

13. The cooling system of claim 10 further includes a circulating reservoir for the liquid phase of the two-phase circulating fluid, the circulating reservoir being fluidly connected to the liquid distribution manifold via a first control valve.

14. The cooling system of claim 13, further comprising a second pump fluidly connected between the circulating reservoir and the first control valve.

15. The cooling system of claim 14, further comprising a pressure sensor located in the steam return manifold, the pressure sensor being communicatively connected to the first control valve and the second pump.

16. The cooling system of claim 10, further comprising an immersion reservoir for the liquid phase of the two-phase immersion fluid, the immersion reservoir being fluidly connected to the immersion tank via a second control valve.

17. The cooling system of claim 16, further comprising a third pump fluidly connected between the immersion reservoir and the second control valve.

18. The cooling system of claim 17, further comprising a level sensor located in the immersion tank, the level sensor being communicatively connected to the second control valve and the third pump.

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