cold plate

Abstract

A cold plate includes a housing having a surface that provides a thermal interface for cooling an electronic device, a channel within the housing proximate to the surface for liquid coolant to flow through the channel such that heat received by the thermal interface is transferred to the liquid coolant, and a coolant port extending outside the housing for communicating the liquid coolant to and / or from the channel. A cross-sectional area from the coolant port to an outlet of the channel can be no greater than a cross-sectional area of the channel at the outlet. Fins and / or fins can be disposed within the channel proximate to the coolant port. The coolant port can allow the liquid coolant to enter and / or exit the channel in a direction perpendicular to the surface. The coolant port can include a separate swivel fluid connector, thereby allowing adjustment of a direction of a tube coupled to the coolant port.

Description

Technical Field

[0001] This disclosure relates to cold plates, electronic modules including at least one cold plate, and electronic systems including multiple such electronic modules. Background Technology

[0002] Printed circuit boards (PCBs) exist within computers, servers, and other devices used for data processing (referred to as information technology or IT). On these PCBs are small devices called integrated circuits (ICs), which can include central processing units (CPUs), application-specific integrated circuits (ASICs), graphics processing units (GPUs), and so on. All of these can be collectively referred to as chips.

[0003] IT systems are typically housed within chassis, enclosures, or shells. For example, in servers, this enclosure is sometimes called a server chassis. Server chassis generally adhere to many industry standards specifying the height of each chassis, which are referred to as 1RU (a rack unit) or 1OU (an open unit), also abbreviated as 1U or 1OU. The smaller of the two main standards is 1RU / 1U, which has a height of 44.45 mm or 1.75 inches. Such units can be called blade servers.

[0004] Different server products can utilize more than one RU / OU per chassis, for example, a 2U chassis can use two rack units. The size of each server chassis is typically kept to a minimum to maximize the computing power of each server rack (a server rack is the main enclosure to which the server chassis are added).

[0005] Chips used in IT typically employ air cooling. This usually involves a heatsink with fins or similar features positioned in direct contact with the chip surface, or the heatsink being positioned with a TIM (thermal interface material) between the two components. In addition to the heatsink, each enclosure uses a series of fans to blow air across the enclosure, remove heat from the heatsink, and exhaust heat from the chassis.

[0006] Recently, the peak performance of heat-generating chips has been suppressed due to limitations in air-cooled equipment. As technology halves in size every few years while maintaining the same performance (Moore's Law), the heat generated by chips increases as the component's footprint decreases. This also leads to an increase in the size and complexity of heat sinks. This typically translates to an increase in server chassis size, thereby reducing the computing power within a single rack.

[0007] This has prompted the search for ways to cool these heat-generating components more efficiently than large air-cooled radiators. Various methods explored include using liquids as coolants. These liquids include dielectric fluids, mineral oils, and water, among others. Many existing methods using liquid cooling are known. For example, International Patent Publication No. 2018 / 096362, assigned co-transmitted with this disclosure, describes an immersion liquid cooling method. Such methods offer high performance and efficiency, but they require specialized server enclosures to hold the liquid coolant. It is desirable to provide a non-immersion liquid-based system with high performance and efficiency. Summary of the Invention

[0008] Against this backdrop, cold plates, electronic modules, and electronic systems were provided.

[0009] In this embodiment, a cold plate with a housing (outer housing) is provided, the surface of which provides a thermal interface for cooling electronic devices (e.g., chips or ICs). This surface is typically the bottom surface of the housing. At least one channel is disposed within the housing and close to the surface, and liquid coolant can flow through this channel (or multiple channels, which may be in series or parallel) to receive heat through the thermal interface. The liquid coolant (which may be water or water-based) enters and exits the channel (or multiple channels) through one or more coolant ports. The coolant ports (or multiple ports) extend, for example, perpendicularly to the top surface to the outside of the housing. Advantageously, the cold plate is designed to be single-phase, such that the coolant remains substantially liquid during operation.

[0010] In one key aspect, the coolant ports include independent rotary fluid connectors, such as rotary joints (which may be rotary elbow connectors and all these terms are used synonymously herein), thereby allowing adjustment of the orientation of the conduit coupled to the coolant ports. One or more coolant ports are advantageously located on the top surface of the housing. The top surface of the housing can (particularly in terms of its height and / or shape) be configured to allow adjustment of the orientation of the conduit coupled to the coolant ports, for example, by having a height that is smaller around the coolant ports compared to the case away from the coolant ports. In the case where the coolant ports have an elbow shape (such that a first portion extends in a direction generally perpendicular to the top surface and a second portion extends in a direction generally parallel to the top surface), the height difference can approximate the bottom of the elbow shape (i.e., where the transition from the first portion to the second portion begins). Preferably, two coolant ports are provided: one coolant port (inlet coolant port) for receiving coolant from outside the cold plate (e.g., from an external conduit) and supplying it to the channel, and one coolant port (outlet or discharge coolant port) for receiving coolant from the channel (or multiple channels) and transferring it to an external conduit. Any features described with reference to the coolant ports herein can be applied to two coolant ports. The two coolant ports are preferably located at opposite ends of a housing, which may be elongated. Pipes, tubes, or hoses (preferably flexible) are advantageously coupled to one or more coolant ports during operation.

[0011] Advantageously, rotary joints enable significant flexibility in cold plate placement and thus improve efficiency. The use of rotary joints allows cold plates to be placed in various locations within a housing (e.g., a server chassis) and in various orientations. In this way, more optimized cold plate placement can be provided compared to what can be achieved using fixed coolant ports (or multiple fixed coolant ports). Preferably, the rotary joint allows adjustment of the pipe orientation about an axis perpendicular to the top surface of the housing and / or allows free 360-degree rotation. In particular, the cold plate can be flexibly mounted on / within existing hardware. By rotating the connector, installers can select the most efficient route for pipes, tubes, or hoses to enter and exit the server chassis. Rotation of the nozzle or connector can help guide tubes or hoses around existing components. Tubes or hoses connected to the cold plate can be guided between existing components, and rotation on the connector also helps prevent excessive bending radii on the tubes. These benefits correspondingly improve performance and efficiency. Cold plates of different sizes can be used to cool a wide variety of chips or heat-generating components and can be mechanically mounted to various mounting points.

[0012] In another major aspect (which may be combined with other major aspects or any other aspects), one or more features are provided that can reduce pressure drop and / or provide a low (preferably minimal) pressure drop between the pipes outside the cold plate and the inside of the cold plate.

[0013] Specifically, one or more features include one or more of the following: (a) the liquid coolant enters and / or exits the channel in a direction perpendicular to the thermal interface surface (and / or the bottom surface of the channel, typically close to the thermal interface surface of the housing); (b) the cross-sectional area from the coolant port to the channel outlet is not greater than the cross-sectional area of ​​the channel at the outlet (in other words, the flow rate of the channel is at least as large as the flow rate at the coolant port outlet); and (c) fins and / or ribs are arranged within the channel, adjacent to the coolant port (particularly its outlet), so that the liquid coolant entering at least one channel flows in all directions in a plane parallel to the surface (and / or the bottom surface of the channel). Referring to (c), for example, the coolant port is arranged relative to the fins and / or ribs to facilitate omnidirectional or radial jet flow of the liquid coolant. Each of these can facilitate coolant flow within the channel (or channels), particularly towards the second coolant port (serving as the external outlet of the cold plate). In this way, pressure drop can be reduced or minimized.

[0014] All aspects can be achieved by mounting the cold plate onto the heat-generating chip or component (electronic device) in the same or similar manner as current air-cooled radiators. By repurposing the cold plate to the same mounting point, it is easier to integrate the product into existing hardware.

[0015] In any respect, fins and / or ribs are advantageously arranged within one or more channels (and in practice, multiple channels may be defined in some embodiments). The fins and / or ribs may extend from the bottom surface of the channel and more preferably to the top surface of the channel (opposite to the bottom surface). The fins and / or ribs may be arranged within a portion or all of the channel, but particularly around the coolant ports (or multiple coolant ports).

[0016] In a preferred embodiment, fins and / or ribs are arranged in a regular, uniformly distributed pattern and / or the fins and / or ribs are arranged to prevent unobstructed flow of liquid coolant between the coolant port acting as a coolant inlet and the coolant port acting as a coolant outlet. Such an arrangement (or multiple arrangements) can be provided throughout the channel, or the arrangement can vary, wherein such an arrangement is provided around the coolant ports (or multiple coolant ports), and different arrangements of fins and / or ribs are provided in the middle portion of the channel (e.g., the middle portion of the channel has fins that allow unobstructed flow between the inlet and outlet ports, e.g., using only fins). The channel width in this middle portion of the channel can be smaller than the channel width around the ports.

[0017] In some embodiments, the ribs and / or fins are spaced at least 1 mm to 8 mm, more preferably 3 mm to 5 mm, and most preferably 3.5 mm to 4.5 mm (measured from rib center to rib center). In other embodiments, the ribs and / or fins are spaced 1.5 (or 2) to 3 times the rib diameter (or fin width), and more preferably 2 to 2.5 times the rib diameter (again, measured from rib center to rib center). The rib diameter or fin width can be between 1 mm and 3 mm, and more preferably about 2 mm. Such a configuration can provide low (or reduced) pressure drop across the cold plate and / or mitigate the risk of liquid-based contaminant and growth fouling.

[0018] In this implementation, the heat pipe or vapor chamber can be disposed within the housing of the cold plate, between the thermal interface surface and the channel. This can increase (or maximize) the effective conduction or diffusion from the central heat flux region of a given chip or IC to the inlet and outlet (exhaust) regions.

[0019] A cold plate can form part of an electronic module, such as a computer system or server. This electronic module may include a module housing (e.g., a server chassis) within which electronic equipment is mounted. The electronic equipment may include, for example, one or more chips or ICs mounted on a PCB (and in practice, the electronic equipment may include a portion of the PCB or the entire PCB). The cold plate is mounted on the electronic equipment such that heat generated by the electronic equipment is transferred through the thermal interface of the cold plate. The module housing may have openings through which one or more pipes coupled to coolant ports of the cold plate can pass, allowing liquid coolant to flow between the interior and exterior of the module housing.

[0020] The module housing is typically substantially planar (e.g., having an elongated cuboid shape) and may define a height dimension (Z) perpendicular to the plane of the housing (typically 1 rack unit or approximately 44 mm to 45 mm). The combined dimensions of the electronics and the cold plate in the height dimension typically fill the housing, usually at least 80%, 85%, 90%, or 95% of the module housing's dimensions in the height dimension. In other words, the Z height of the cold plate assembly is adapted to a 1U server chassis when attached to a heat-generating component (although in some cases, server chassis larger than 1U may be used). The described cold plate can vary in its overall dimensions. This can depend on the type of socket (fixed point) to which it is attached and the required heat dissipation capacity of the cold plate. The performance of the cold plate can be the same as an air-cooled radiator, but typically within the reduced Z height of the air-cooled radiator it replaces.

[0021] Multiple electronic devices (e.g., multiple chips or ICs on the same PCB or different PCBs) can be housed inside the module housing. Multiple devices can then be cooled using more than one cold plate, with each cold plate thermally coupled to at least one electronic device.

[0022] The piping system is advantageously coupled to the coolant port of each cold plate for conveying liquid coolant to and from the respective cold plate. The piping system is preferably arranged to convey liquid coolant to and from the cold plates in series or in parallel. Some cold plates may be connected in series, while others may be connected in parallel in a different arrangement (e.g., a combination of series and parallel coupling). This is made easier by rotating the coolant ports (using rotary joints).

[0023] An electronic device or server system may also be provided, comprising multiple electronic modules (e.g., servers), each of which conforms to the embodiments described herein. A piping network can be configured to deliver liquid coolant to and from each of the electronic modules. A heat exchanger device can then be used to receive the liquid coolant from each of the electronic modules via the piping network, transferring heat from the received liquid coolant to at least one radiator (which may be, for example, air or liquid). Thus, the heat exchanger can cool the liquid coolant. The cooled liquid coolant can then be (e.g., in a closed-loop manner) directed to the multiple electronic modules. The piping network can deliver the liquid coolant to and from the multiple electronic modules serially or in parallel (or a combination of serial and parallel coupling).

[0024] Electronic modules (especially when each is a server, such as a blade server) can be arranged in one or more racks, and preferably in multiple racks. Each rack can hold 42 such modules. A single pump can then be able to pump all the liquid coolant within the piping network to all modules (which can fill multiple racks, providing at least 43 modules). Each module can have at least one cold plate (and preferably multiple cold plates) for receiving the liquid coolant. Attached Figure Description

[0025] This disclosure can be implemented in various ways, and preferred embodiments will now be described by way of example only and with reference to the accompanying drawings, in which:

[0026] Figure 1 An embodiment of the cold plate according to this disclosure is illustrated schematically;

[0027] Figure 2A The first configuration is shown. Figure 1 A top view of the implementation method;

[0028] Figure 2B The second configuration is shown. Figure 1 A top view of the implementation method;

[0029] Figure 3A The following is shown based on the first serial configuration. Figure 1 A top view of the two coupled cold plates in the embodiment;

[0030] Figure 3B The second serial configuration is shown according to Figure 1 A top view of the two coupled cold plates in the embodiment;

[0031] Figure 3C The third serial configuration is shown according to Figure 1 A top view of the two coupled cold plates in the embodiment;

[0032] Figure 4A The following is shown based on the parallel configuration. Figure 1 A top view of the two coupled cold plates in the embodiment;

[0033] Figure 4B It shows according to Figure 1 A top view of the cold plate in the first variant of the implementation method;

[0034] Figure 4C It shows according to Figure 1 A top view of the cold plate in a second variation of the implementation method;

[0035] Figure 5A perspective view of an example blade server with a cold plate installed is depicted;

[0036] Figure 6 It shows Figure 5 A side view of the implementation method;

[0037] Figure 7 It shows Figure 6 The enlarged portion, which schematically depicts the internal details of the cold plate;

[0038] Figure 8A An internal top view of a cold plate according to an embodiment of the present disclosure is depicted;

[0039] Figure 8B It shows Figure 8A A side view of the implementation method;

[0040] Figure 9 It shows Figure 8A The enlarged portion has additional details;

[0041] Figure 10A Depicting Figure 8A An internal top view with additional details about coolant flow;

[0042] Figure 10B Depicting Figure 8A An internal top view of a variant of the implementation, with additional details regarding coolant flow;

[0043] Figure 11A An internal cross-sectional view of the cold plate according to a first further embodiment is shown;

[0044] Figure 11B It shows Figure 11A A bottom perspective view of the implementation method;

[0045] Figure 11C Depicting Figure 11A A bottom view of the implementation method;

[0046] Figure 12A An internal cross-sectional view of the cold plate according to a second further embodiment is shown;

[0047] Figure 12B It shows Figure 12A A bottom perspective view of the implementation method;

[0048] Figure 12C Depicting Figure 12A A bottom view of the implementation method;

[0049] Figure 13A A schematic diagram of an existing single-rack server cooling system is shown.

[0050] Figure 13B A schematic diagram of a single-rack server cooling system according to this disclosure is shown; and

[0051] Figure 14 A schematic diagram of a multi-server cooling system according to this disclosure is shown. Detailed Implementation

[0052] First refer to Figure 1 The following diagram schematically illustrates an embodiment of a cold plate (or cold plate assembly) according to this disclosure. This is advantageous for use in server blades (or similar modules), as will be discussed below. The cold plate assembly includes: a cold plate 210 (preferably integrally formed); a rotary elbow connector 200; and inlet / outlet pipes 205. Fixing points 215 on the cold plate 210 are also shown. These fixing points advantageously replicate those found on air-cooled radiators from which the cold plate can be replaced. The rotary elbow connector (or rotary joint) 200 is particularly useful when configuring the cold plate assembly for operation, as will now be explained.

[0053] The top surface of the cold plate 210 is recessed around the rotary elbow connector 200, such that the height of the cold plate 210 in the recessed area is lower than its height in the central portion of the top surface. This further allows for the free rotation of the rotary connector 200.

[0054] Reference Figure 2A This shows the configuration in the first setting. Figure 1 A top view of the implementation. The rotation of the swivel elbow connector 200 can be seen, especially the rotation relative to the recessed portion of the top surface, which has a roughly hexagonal shape in the plan view. In this example, it will be noted that the inlet and outlet hoses / pipes 205 can pass over the body of the cold plate without obstruction.

[0055] Reference Figure 2B This shows the second configuration. Figure 1 A top view of the implementation. In this illustration, the inlet and outlet hoses / pipes 205 are positioned away from the cold plate body 210 in any direction. This is also permitted by the recessed portion of the top surface and the swivel elbow connector 200.

[0056] Generally, a cold plate comprising a housing (which may be integrally formed) is thus conceivable, the surface of which (typically planar) is arranged to provide a thermal interface (which may be referred to as a conductive surface) for cooling electronic equipment thermally coupled to the surface. The cold plate also includes at least one channel within the housing and adjacent to the surface. One or more channels may be formed by internal chambers (or multiple chambers), volumes, or other spaces for accommodating a liquid coolant (e.g., water, a water-based coolant, a coolant substantially containing water, or a liquid substitute with a high specific heat capacity). One or more channels are arranged for the liquid coolant to flow through one or more channels, such that heat received by the thermal interface is transferred to the liquid coolant. Optionally, multiple parallel channels may be provided, each extending from a coolant port. As will be discussed further below, fins and / or ribs are preferably arranged within at least one channel.

[0057] The cold plate also includes a coolant port extending outside the housing for conveying liquid coolant to and / or from at least one channel. The coolant port may be a connector, coupler, joint, or other similar structure. At least one conduit, hose, or tube (preferably flexible) may be coupled to the coolant port for conveying liquid coolant to and / or from the coolant port. Advantageously, the cold plate is configured such that the liquid coolant remains substantially liquid (i.e., single-phase liquid cooling).

[0058] In one aspect of this disclosure, the coolant port includes a separate rotary fluid connector, which may be in the form of a rotary joint (or rotary elbow connector, all these terms are used synonymously herein), thereby allowing adjustment of the orientation of the piping coupled to the coolant port. A separate rotary fluid connector or rotary joint can increase the flexibility of cold plate placement. This can allow the cold plate to be retrofitted to existing electronic units such as servers or other computer systems without requiring any additional modifications to the unit or system. For example, the cold plate can be configured to be installed in place of an air-cooled radiator.

[0059] Preferably, the surface arranged to provide the thermal interface is the bottom surface of the housing. The coolant port is then advantageously located on the top surface of the housing opposite the bottom surface. In a preferred embodiment, the coolant port (e.g., in the first portion) extends in a direction perpendicular to the top surface of the housing. The rotary joint can then extend the coolant port in different directions (e.g., the second portion), typically more parallel or substantially parallel to the top surface of the housing. This can be referred to as an elbow shape, for example, having a bend between the first and second portions. Advantageously, the rotary joint allows adjustment of the pipe's direction about an axis perpendicular to the top surface of the housing. In particular, the rotary joint can allow the pipe's direction to be adjusted by at least 90 degrees, 180 degrees, 270 degrees, and preferably up to (and including) 360 degrees, especially about an axis perpendicular to the top surface of the housing. Thus, the rotary connector allows for complete rotational freedom of the coolant port.

[0060] The top surface of the housing can be configured (e.g., in terms of its height and / or shape) to allow adjustment of the orientation of the conduit coupled to the coolant port. Specifically, the height and / or shape of the top surface in the portion surrounding the coolant port can differ from the height and / or shape of other portions of the top surface of the housing (particularly, in the case of two coolant ports, in the central portion of the top surface between the top coolant ports) to allow adjustment of the orientation of the conduit coupled to the coolant port. In this context, the term height can refer to the distance between the bottom surface and the top surface (in a direction perpendicular to the bottom surface, which is typically a plane). The height difference can reflect the shape and size of the coolant port, as discussed below, for example.

[0061] The preferred embodiment has a top surface whose height around the coolant port is less than its height away from the coolant port. As discussed above, when the coolant port has a bend shape (such that a first portion extends in a direction generally perpendicular to the top surface and a second portion extends in a direction generally parallel to the top surface), the height difference can be approximately the length of the portion of the coolant port extending from the top surface of the cold plate housing to the base or bottom of the bend shape (i.e., where the transition from the first portion to the second portion begins, such as the base of the bend).

[0062] In principle, a single coolant port can provide an inlet for liquid coolant to the channel and an outlet for liquid coolant from the channel. In a preferred embodiment, multiple coolant ports are used. The coolant port is then a first coolant port for conveying liquid coolant to at least one channel. The cold plate may include a second coolant port for conveying liquid coolant from at least one channel. Any features described herein with reference to a single coolant port can be applied to any of the multiple coolant ports. In embodiments, the housing is elongated, and the first and second coolant ports are located at opposite ends of the housing along its elongation, which can facilitate liquid coolant flow across the thermal interface surface and / or facilitate flexible placement of the cold plate. Additionally or alternatively, the second coolant port may (like the first coolant port) include a swivel joint, thereby allowing adjustment of the orientation of the conduit coupled to the second coolant port. Providing two coolant ports, each with a swivel joint, can allow for improved coupling of the cold plate, including the possibility of coupling the cold plates together.

[0063] Another key advantage of this structure is the ability to use multiple such cold plates together. (See reference) Figure 3A This shows the first serial configuration according to Figure 1 A top view of the two coupled cold plates in this embodiment. Here, the cold plates are horizontally positioned relative to each other, the swivel elbow connector 200 is adjusted accordingly, and the pipe / hose 205 connects the two. (Refer to...) Figure 3B This shows the second serial configuration according to Figure 1 A top view of the two coupled cold plates in this embodiment. The cold plates are vertically positioned relative to each other. The swivel elbow connector 200 allows the pipe / hose 205 to bend around another swivel connector that obstructs the path. (See reference...) Figure 3C This shows the third serial configuration based on Figure 1 The diagram shows a top view of two coupled cold plates in one embodiment. Here, the cold plates are positioned diagonally opposite each other. Rotary elbow connectors 200 are at a 45-degree angle to each other, with a tube / hose 205 connecting them.

[0064] Next, refer to Figure 4A It shows the basis for being in parallel configuration or parallel supply. Figure 1 A top view of the two coupled cold plates in the embodiment. The inlet 220a of the cold plate is split to supply the cold plates in parallel. The outlet 220b is rejoined after splitting to supply the cold plates in parallel.

[0065] Referring to the general terminology used herein, the electronic device can be a first electronic device and the cold plate can be a first cold plate. A second electronic device may then be provided. In that case, a second cold plate (of any type) as disclosed herein can be mounted on the second electronic device such that heat generated by the second electronic device is transferred through the thermal interface of the second cold plate. A conduit arrangement is then advantageously coupled to the coolant ports of the first and second cold plates for conveying liquid coolant to and from the first and second cold plates. In a preferred embodiment, the conduit arrangement is configured to convey liquid coolant serially or in parallel to and from the first and second cold plates.

[0066] The dimensions of the cold plate can be matched to the dimensions of the component or equipment being cooled. See below for further details. Figure 4B , showing according to Figure 1 A top view of the cold plate in a first variation of the implementation. This is a smaller cold plate used for cooling smaller components. (See reference...) Figure 4C , showing according to Figure 1 A top view of the cold plate in a second variation of the embodiment. This is a larger cold plate used for cooling larger components.

[0067] Now refer to Figure 5 This figure depicts a perspective view of an example blade server in which cold plates are mounted. The same reference numerals are used where the same features depicted in other figures are shown. In this example, a 1RU server chassis 245 is shown, with a set of two cold plates 210 on a PCB 240 (motherboard) within the chassis 245. Other components are present on the PCB 240, such as RAM sticks 225 (shown in rows here), capacitors 235 (also shown in rows), and I / O connectors (not shown). A fan 230 is located at the rear of the server chassis 245, removing heat from the chassis 245, as is common in existing units of this type. I / O 250 is located on the front of the board. These components may be USB, QSFP, Ethernet ports, etc.

[0068] As can be seen, the rotating nozzle 200 on the cold plate 210 can rotate to allow the tubes / hose to be optimally guided around existing components such as RAM 225 and capacitor 235. The inlet and outlet tubes, as shown in 220a and 220b, pass through existing holes in the server chassis 245, such as the PCIe card slots as shown.

[0069] Now refer to Figure 6 , showed Figure 5A side view of the implementation is shown. A cold plate is attached to a PCB (e.g., motherboard) 240 on top of the heat-generating chip. The cold plate is also shown to be adapted to a 1RU server height. The base 265 of the chassis 245 is shown having the PCB 240 mounted thereon. The heat-generating chip 255 being cooled by the cold plate 210 is on the PCB 240, and between the heat-generating chip 255 and the cold plate 210 is a thermal interface material (TIM) 270, such as a spacer pad or thermal paste. The distance between the chassis cover 260 and the chassis base 265 is shown as 1RU.

[0070] Now refer to Figure 7 , showed Figure 6 (Especially the left side) An enlarged section schematically depicting the internal details of the cold plate in cross-section. In this example, a rotating nozzle 200 is attached to the lower part of the cold plate, allowing the assembly to be mounted within a 1 RU server chassis. For illustration, the nozzle 200 is shown pointing rearward above the cold plate. A fin 275 is disposed inside the cold plate, and the fin 275 has two distinct height portions. The fin 275 facilitates heat transfer. Placing the inlet and outlet ports at the ends of the cold plate module could result in a reduction in the height of the fin 275.

[0071] Therefore, another general aspect of this disclosure can be considered as an electronic module (e.g., a computer and / or server module or unit, such as a server blade). An electronic module may include: a module housing (e.g., a server chassis); electronic equipment mounted within the module housing (which may include, for example, one or more chips or ICs mounted on a PCB, such as part of a computer server); and a cold plate mounted on the electronic equipment as disclosed herein. In this way, heat generated by the electronic equipment can be transferred through the thermal interface of the cold plate. If the electronic equipment is mounted on a PCB, the cold plate may also be (e.g., using screws, bolts, or similar fastening devices) secured to the PCB for structural and / or thermal bonding between the thermal interface surface of the cold plate and the heat dissipation surface of the electronic equipment.

[0072] Preferably, a conduit (or pipe or hose) is coupled to a coolant port on the cold plate for delivering liquid coolant to and / or from the coolant port. In a preferred embodiment, the module housing includes an opening (e.g., an interface or line-based communication to allow access to electronic equipment or auxiliary components such as daughter card slots or peripheral connection openings). The conduit can then pass through the opening, allowing the liquid coolant to flow (to and / or out of the module housing) both outside and inside the module housing (although typically only within the conduit and the cold plate).

[0073] Cold plates are typically mounted within standard modular housings, particularly in server chassis. The modular housing can be substantially flat (e.g., in the case of server blades). In that case, the modular housing can define a height dimension perpendicular to the housing plane, for example, 1 rack unit (44 mm to 45 mm, more specifically approximately 44.45 mm or 1.75 inches). The combined dimensions of the electronics and the cold plate in the height dimension are advantageously at least 80% (or 85%, 90%, or 95%) of the modular housing's dimensions in that dimension.

[0074] In a preferred embodiment, the second electronic device is mounted within the module housing and a second cold plate (of any type disclosed herein) is mounted on the second electronic device such that heat generated by the second electronic device is transferred through the thermal interface of the second cold plate.

[0075] Other aspects of the cold-plate according to this disclosure will now be discussed. In particular, aspects that result in the cold-plate providing low back pressure will be considered. (Refer to...) Figure 8A The figure depicts an internal (planar) top view of an example cold plate according to an embodiment of this disclosure. For clarity, the cover and nozzle have been removed. A first feature identified as reducing back pressure is the provision of inlet and outlet ports perpendicular to the bottom and / or top surfaces of the cold plate. This has been found to increase (and potentially maximize) omnidirectional flow at the inlet and outlet regions of the internal volume (channel) of the cold plate.

[0076] Figure 8A Shown are: a coolant inlet port 104; a coolant outlet or discharge port 105; a coolant flow channel 106; and fins 109. This configuration distributes the coolant flow 106 in all directions to allow the coolant to be evenly distributed across the entire cold plate. In existing cold plates, the coolant is distributed through channels and baffles, thus increasing the pressure drop.

[0077] The second feature of reducing back pressure is that the inlet port 104 and the outlet port 105 are aligned above the internal rib / fin arrangement 109. This also facilitates omnidirectional or radial jet flow 106 of fluid entering and exiting the outlet point within the cold plate module.

[0078] Reference Figure 8B , showed Figure 8A A side (sectional) view of the embodiment includes a nozzle 108, a cold plate base 111, and a cold plate cover 112. This illustrates a third advantageous feature of the embodiment, wherein the cross-sectional area 107 between the outlet of the nozzle 108 and the cold plate base 111 is equal to or greater than the cross-sectional area of ​​the nozzle 108 and the hose. The effect of this is to maximize the effective cross-sectional area to reduce (or minimize) the pressure drop.

[0079] A fourth advantageous feature is also shown, wherein the rib 109 is connected to the base 111 and the cover 112. This ensures that no flow 106 can take a shortcut to avoid or bypass the rib 109. In this way, the rib 109 can guide the coolant flow 106 within the cold plate, as will be discussed now.

[0080] Now refer to Figure 9 , showed Figure 8A The enlarged portion, with additional details, shows a fifth advantageous feature where the ribs (and / or fins) 109 are non-directional and allow natural radial flow from the vertical inlet and outlet ports. It also shows a sixth advantageous feature where the line of sight does not pass through the ribs, as indicated by the flow line 110. This can promote non-linear flow and / or radial flow. This can also reduce pressure drop. For example, the ribs can be formed in offset rows or with a tessellated triangular spacing. In such a configuration, the angle of the triangle formed between the centers of three adjacent ribs (two ribs in one row and the third rib in an adjacent parallel row, in the middle column) can all be 60 degrees.

[0081] A seventh advantageous feature can also be deduced from the figure, particularly that the spacing between the fins and / or slats 109 can be configured to promote coolant flow and reduce the risk of liquid-side contaminant and growth fouling. Such a gap or interval thus reduces (or minimizes) the pressure drop across the cold plate while still promoting radial flow and providing low thermal resistance (thus promoting heat transfer). Spacing between 1.5 (or 1.75) times and more preferably 2 to 2.5 times the fin diameter (measured between the centers of the fins or slats) has been found to be advantageous. In embodiments, fin or slat diameters between 1.5 mm and 3 mm (more typically about 2 mm) have been used. In practice, the gap between fins (measured from the edge or plane of the fin to the edge or plane of the adjacent fin) can be between 1 mm and 4 mm, or more preferably between 1.75 mm or 2 mm and 3 mm, particularly for fins with a diameter of 2 mm to 2.3 mm. It should be noted that the cross-section of the ribs does not have to be circular; for example, they may have a hexagonal cross-section.

[0082] Although the seven advantageous features and synergistic benefits can be seen through the combination of several of these advantageous features, they can be used individually or in any combination.

[0083] Therefore, other generalized aspects of this disclosure can be considered as any type of cold plate disclosed herein having a configuration for providing low pressure drop. In embodiments, coolant ports are configured to allow liquid coolant to enter and / or exit at least one channel in a direction perpendicular to the surface, or coolant ports are arranged relative to fins and / or ribs to facilitate omnidirectional or radial jet flow of liquid coolant.

[0084] The implementation may limit the cross-sectional area from the coolant port to the outlet of at least one channel to be no greater than the cross-sectional area of ​​at least one channel at that outlet.

[0085] Some implementations may include arranging fins and / or ribs within at least one channel, adjacent to a coolant port, so that liquid coolant entering at least one channel flows in all directions in a plane parallel to the surface.

[0086] In one embodiment, ribs and / or fins are arranged to extend from the bottom surface of at least one channel, which is close to the surface of the housing arranged to provide a thermal interface. Preferably, the ribs and / or fins are arranged to extend to the top surface of at least one channel, which is away from the surface of the housing arranged to provide a thermal interface.

[0087] In cases where multiple coolant ports are provided, fins and / or ribs are advantageously arranged within at least one channel, at least adjacent to the first coolant port and / or the second coolant port. In such areas, the fins and / or ribs may be arranged in a regular, uniformly distributed pattern and / or the fins and / or ribs may be arranged to prevent unobstructed flow of liquid coolant between the first and second coolant ports. For example, offset, uniformly spaced rows of fins may be provided.

[0088] In some embodiments, fins and / or ribs are arranged in a regular, uniformly distributed pattern throughout at least one channel. Alternatively, fins and / or ribs may be arranged in a first pattern in a first portion of at least one channel adjacent to a first coolant port and / or a second coolant port. Then, fins and / or ribs may be arranged in a different second pattern in a second portion of at least one channel spaced apart from the first coolant port and / or the second coolant port. For example, the first pattern may be composed of fins and the second pattern may be composed of ribs. The width of the channel (which may be defined by an internal volume, regardless of fins or ribs) in the first portion may be wider than its width in the second portion. Optionally, the first pattern is configured to prevent unobstructed flow of liquid coolant between the first coolant port and the second coolant port, and the second pattern is configured to allow unobstructed flow of liquid coolant between the first coolant port and the second coolant port (e.g., by using linearly arranged or straight-lined fins). A first portion of at least one channel may be adjacent to a first coolant port, wherein fins and / or ribs are also arranged in a first pattern (or a pattern with a similar effect) in a third portion of at least one channel adjacent to a second coolant port. A second portion of at least one channel may then be located between the first and third portions.

[0089] Specific embodiments may provide ribs spaced at least 1.75 times or 2 times the diameter of the ribs or fins, and up to 2.5 times or 3 times the diameter of the ribs or the width of the fins, measured from the center of the rib or fin to the center of the adjacent rib or fin. For example, for ribs with a diameter of 2 mm, the gap between the ribs (measured from the edge of the rib to the edge of the adjacent rib) may be between 1.5 mm and 4 mm, or more preferably between 2 mm and 3 mm. Such spacing can facilitate coolant flow and reduce the risk of fouling caused by liquid-side contaminants and growths.

[0090] Reference Figure 10A It depicts Figure 8A An internal top (plan) view shows additional details regarding coolant flow. It can be seen that the fin / rib arrangement within the cold plate module at the inlet and outlet ports allows for radial flow discharge (i.e., provides omnidirectional flow) 106. This can be attributed to the regularly offset fin arrangement, as discussed above. However, a more linear and parallel flow region 113 can be observed in a more central area within the cold plate module.

[0091] Because the flow is more linear within the central region, variations in the layout within that region can be provided without sacrificing performance. (Refer to...) Figure 10B It depicts Figure 8AAn interior top view of a variant of the embodiment, with additional details regarding coolant flow. Here, fins 114 are positioned in a more central, linear and / or parallel flow region.

[0092] The base of the cold plate can be reinforced to promote heat transfer and improve performance. (See reference:) Figure 11A An internal cross-sectional view of the cold plate according to a first further embodiment is shown; Figure 11B , showed Figure 11A The bottom perspective (isolated) view of the embodiment; and Figure 11C It depicts Figure 11A A top (bottom) view of the implementation. In this design, an embedded vapor chamber 115 is shown to increase the effective conduction or diffusion from the central heat flux region of a given chip to the inlet and outlet regions.

[0093] Reference: Figure 12A An internal cross-sectional view of the cold plate according to a second further embodiment is shown; Figure 12B , showed Figure 12A The bottom perspective (isolated) view of the embodiment; and Figure 12C It depicts Figure 12A A bottom (top) view of the implementation. Here, an embedded heat pipe 116 is shown as an alternative to increase efficient conduction or diffusion from the central heat flux region of a given chip to the inlet and outlet regions.

[0094] Generally, the cold plate can optionally also include a heat pipe or vapor chamber (advantageously within the housing) between the surface arranged to provide a thermal interface and at least one channel. This can facilitate heat transfer across the thermal interface.

[0095] Now refer to Figure 13AConsidering the advantages of reduced pressure drop in more detail, a schematic diagram of an existing single-rack server cooling system is shown. This includes: a server chassis 300; a cold plate 320; a water-based cooling loop 330; a manifold 340; a cooling distribution unit (CDU) 350; and a radiator 380. The server chassis can be mounted within a rack 310, where the manifold 340 is used to direct coolant to and from other servers (not shown). In such existing designs, multiple pumps are provided. A separate pump is located within the cold plate 320 (i.e., a pump at the cold plate 320 level), which can facilitate coolant distribution. A manifold-level pump 335 is also provided in many such designs. Additionally, a facility-level pump 370 is used. Due to the high pressure drop within each cold plate, a local pump is required to distribute the coolant. Such a design where the facility-level pump 370 is in the CDU 350 can also be described as a rack-level CDU. The CDU 350 includes a heat exchanger 360 for transferring heat to the radiator 380. Radiator 380 can be liquid-based or air-based, depending on the facility, such as an additional coolant circuit including a heat dissipation unit.

[0096] Using multiple pumps in this way has a number of disadvantages. These disadvantages include: multiple pumps increase costs (in some examples, each server chassis may have four integrated cold plate pumps); each pump is a potential point of failure; each pump has power consumption, thus increasing the total power consumption; each pump will need to be interconnected to balance the flow across the entire system, which increases complexity; facility-level pump 370 is still needed to circulate facility coolant; and pump redundancy can only be added at manifold-level pump 335 or cold plate level 320.

[0097] Reducing the pressure drop at each cold plate allows for a significant reduction in the number of pumps and has associated benefits. (Refer to...) Figure 13B A schematic diagram of a single-rack server cooling system according to this disclosure is shown. (The diagram is in conjunction with...) Figure 13A Where features are identical, the same reference numerals are used. A cold plate 390 with a lower pressure drop is provided according to this disclosure. In this configuration, only a facility-level pump 370 is used to distribute coolant to all cold plates 390 in the rack 310. Benefits include: all coolant typically circulates within the CDU 350 via a single facility-level pump (although this is not required), eliminating the need for additional pumps during normal operation; coolant flow can be balanced through the design of the manifold 340; and increased pump redundancy in the facility cooling loop requires only one additional pump, which does not need to operate during normal use. Other benefits will be appreciated in light of the foregoing considerations.

[0098] Figure 14A schematic diagram of a multi-server cooling system according to this disclosure is shown. This illustrates a server chassis 400 shown for each rack 410, wherein multiple such racks 410 are provided, each rack capable of accommodating up to 42 server chassis 400. A single CDU 450 provides a water-based cooling loop 430 across all racks. The CDU 450 includes a heat exchanger 460 and a facility-level pump 470, wherein heat is transferred to a radiator 480. Therefore, a single pump 470 can be used in a system with hundreds of server chassis 400.

[0099] In summary, embodiments according to this disclosure offer a number of benefits. These are particularly advantageous in cold plates used for cooling dense applications (e.g., 1U servers in multiple racks) and for cooling electronic devices in ultra-dense applications. Positioning the inlet and outlet ports perpendicular to the cold plate module maximizes omnidirectional flow at the inlet and outlet regions. Positioning the inlet and outlet ports at the ends of the cold plate module may result in a reduction in the required rib or fin height. Aligning the inlet and outlet ports in the rib / fin arrangement promotes omnidirectional or radial jet flow at the fluid entry and exit points within the cold plate module (increasing or maximizing the effective cross-sectional area and / or reducing inlet and outlet pressure drops). Providing a rib / fin arrangement at the inlet and outlet regions of the cold plate allows coolant flow to be radially discharged towards the center of the cold plate into linear and parallel flow regions. Providing a large effective rib / fin gap or spacing reduces the risk of fouling due to liquid-side contaminants and growths. Using an enhanced base on a cold plate with embedded heat pipes or vapor chambers can increase (or maximize) the effective conduction or diffusion from the central heat flux region of a given chip to the inlet and outlet regions.

[0100] In another aspect of this disclosure, an electronic system comprising one or more electronic modules (e.g., blade servers or other computing units), and preferably multiple electronic modules, each according to this disclosure, can be considered. In a preferred embodiment, the multiple electronic modules are arranged in multiple racks, each rack optionally capable of accommodating up to 42 electronic modules. A piping network can be configured to deliver liquid coolant to and from each electronic module. A heat exchanger device is then advantageously arranged to receive liquid coolant from each electronic module via the piping network and transfer heat from the received liquid coolant to at least one radiator. This can thereby cool the liquid coolant. The cooled liquid coolant can then be directed (back) to the multiple electronic modules. In other words, a closed loop for the liquid coolant can be provided across multiple cold plates. The piping network can be arranged to deliver liquid coolant to and from the multiple electronic modules serially or (more preferably) in parallel. Advantageously, a single pump can be configured to pump all the liquid coolant within the piping network (although redundancy can be provided, even if not required for normal operation). This pump can supply liquid coolant to a large number of electronic modules (without any other pumps in the system), such as at least 20, 40, 43 (i.e., two racks, at least one of which is full), 50, 100, 150, 200 or more. This advantage is possible through the use of a cold plate according to this disclosure.

[0101] Additional aspects of this disclosure may include a method of mounting a cold plate according to this disclosure in an (already-operated) electronic module (e.g., a server). For example, the method may include securing the cold plate to one or more electronic devices within the electronic module. In one embodiment, this may include securing the cold plate instead of an air-cooled radiator or using the cold plate instead of an air-cooled radiator. In another aspect, a method of operating an electronic system comprising multiple electronic modules, each having at least one cold plate, may be provided. The method may include pumping liquid coolant through multiple cold plates (in the same and / or different electronic modules) to cool one or more electronic devices in each electronic module. Method steps corresponding to any of the apparatus or structural features disclosed herein (regarding provision, installation, configuration, arrangement, use, operation, or the like) may also be contemplated.

[0102] Although specific embodiments have now been described, those skilled in the art will understand that various modifications and alternatives are possible. For example, the structure and / or design of the cold plate may differ from those shown. Other shapes and applications are possible. For instance, a stepped bottom (thermal interface) surface (with multiple parallel planes) may be used, but a flat surface is preferred.

[0103] All features disclosed herein can be combined in any combination, except that at least some of such features and / or steps are mutually exclusive combinations. In particular, preferred features of the invention apply to all aspects of the invention and can be used in any combination. Similarly, features described in non-essential combinations may be used alone (rather than in combination).

Claims

1. A cold-rolled steel plate, comprising: A housing, the surface of which is arranged to provide a thermal interface for cooling electronic devices thermally coupled to the surface; At least one channel within the housing and near the surface, the at least one channel being arranged for liquid coolant to flow through the at least one channel, such that heat received by the thermal interface is transferred to the liquid coolant; as well as A first coolant port is used to deliver liquid coolant to the at least one channel; And a second coolant port for conveying liquid coolant from the at least one channel, wherein fins and / or ribs are arranged within the at least one channel, at least adjacent to the first coolant port and / or the second coolant port but not below it, such that liquid coolant entering the at least one channel flows in all directions in a plane parallel to the surface; in: (a) The cross-sectional area from the coolant port to the outlet of the at least one channel is not greater than the cross-sectional area between the outlet and the bottom surface of the at least one channel, the bottom surface being close to the surface of the housing arranged to provide the thermal interface; (b) The first coolant port is configured to allow liquid coolant to enter the at least one channel in a direction perpendicular to the surface, and the second coolant port is configured to allow liquid coolant to exit the at least one channel in a direction perpendicular to the surface; (c) The fins and / or ribs are arranged in a regular, uniformly distributed pattern within the at least one channel, adjacent to the first coolant port and / or the second coolant port, and / or the fins and / or ribs are arranged to prevent unobstructed flow of liquid coolant between the first coolant port and the second coolant port; and (d) The ribs and / or fins are arranged in a first pattern in a first portion of the at least one channel adjacent to the first coolant port and / or the second coolant port, and in a different second pattern in a second portion of the at least one channel spaced apart from the first coolant port and / or the second coolant port.

2. The cold-rolled plate according to claim 1, wherein, The ribs and / or fins are spaced apart by at least 1.5 times the diameter of the ribs or the width of the fins.

3. The cold-rolled plate according to claim 1 or claim 2, wherein, The ribs and / or fins are arranged to extend from the bottom surface of the at least one channel to the top surface of the at least one channel, the bottom surface being close to the housing and arranged to provide the thermal interface, and the top surface being away from the housing and arranged to provide the thermal interface.

4. The cold-rolled plate according to claim 1 or claim 2, wherein, One or two of the following: Wherein, the width of the at least one channel in the first part is greater than the width of the at least one channel in the second part; The first mode is configured to prevent unobstructed flow of liquid coolant between the first coolant port and the second coolant port, and the second mode is configured to allow unobstructed flow of liquid coolant between the first coolant port and the second coolant port.

5. The cold-rolled plate according to claim 1 or claim 2, wherein, The first portion of the at least one channel is adjacent to the first coolant port, and the fins and / or ribs are arranged in the first pattern in the third portion of the at least one channel adjacent to the second coolant port, the second portion of the at least one channel being between the first portion and the third portion.

6. The cold-rolled plate according to claim 1 or claim 2, wherein, The coolant port includes a separate rotary fluid connector, which allows adjustment of the direction of the pipe coupled to the coolant port.

7. The cold-rolled plate according to claim 1 or claim 2, wherein, One or two of the following: The second coolant port includes an independent rotary fluid connector, thereby allowing adjustment of the direction of the pipe coupled to the second coolant port; The housing is elongated, and the first coolant port and the second coolant port are located at opposite ends of the housing along the elongation direction.

8. The cold-rolled plate according to claim 1 or claim 2, wherein, One or more of the following: The cold plate further includes: a heat pipe or vapor chamber within the housing, the heat pipe or vapor chamber being located between the surface arranged to provide a thermal interface and the at least one channel; The at least one channel includes a plurality of parallel channels, each of which extends from the coolant port; The cold plate is configured such that the liquid coolant remains substantially in a liquid state; The cold plate further includes: a flexible conduit coupled to the coolant port for conveying liquid coolant to and / or from the coolant port.

9. An electronic module, comprising: Module housing; Electronic devices installed within the module housing; as well as The cold plate according to any one of claims 1 to 8 is mounted on the electronic device such that heat generated by the electronic device is transferred through the thermal interface of the cold plate.

10. The electronic module according to claim 9, wherein, One or more of the following: The electronic module further includes: a conduit coupled to the coolant port for conveying liquid coolant to and / or from the coolant port; and wherein the module housing includes an opening through which the conduit passes, allowing the liquid coolant to flow to the outside of the module housing; The electronic device is a first electronic device, and the electronic module further includes: a second electronic device installed in the module housing; and a cold plate according to any one of claims 1 to 8, wherein the cold plate is installed on the second electronic device such that heat generated by the second electronic device is transferred through the thermal interface of the cold plate; The electronic device is at least a part of a computer server, such that the electronic module is a computer server module.

11. The electronic module according to claim 9 or claim 10, wherein, The module housing is substantially planar and defines a height dimension perpendicular to the plane of the housing, wherein the combined dimension of the electronic device and the cold plate in the height dimension is at least 80% of the dimension of the module housing in the height dimension.

12. The electronic module according to claim 11, wherein the module housing has a dimension of 1 rack unit in the height dimension.

13. An electronic system comprising: A plurality of electronic modules, each of the plurality of electronic modules being according to any one of claims 9 to 12; A piping network is configured to deliver liquid coolant to and from each of the electronic modules; as well as A heat exchanger device is arranged to receive liquid coolant from each of the electronic modules via the network of pipes, transfer heat from the received liquid coolant to at least one radiator, thereby cooling the liquid coolant and directing the cooled liquid coolant to the plurality of electronic modules.

14. The electronic system according to claim 13, wherein, One or more of the following: The piping network is arranged to deliver liquid coolant to and from the plurality of electronic modules in a serial or parallel manner. The plurality of electronic modules are arranged in multiple racks, and the electronic system further includes: a single pump configured to pump all liquid coolant within the piping network; The liquid coolant essentially comprises water.

15. The electronic system according to claim 14, wherein, The number of electronic modules is at least 43.

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