Liquid-cooled cold plate assembly for electronic devices

Abstract

A cold plate assembly for use in a liquid cooling system for cooling a computing device having a plurality of working regions from which heat diffuses at varying intensities from one or more high intensity regions to one or more low intensity regions. The cold plate assembly has a cold plate for exchanging heat between the computing device and the cooling liquid and a distribution layer configured to be mounted to the cold plate. The cold plate comprises guiding means for guiding the cooling liquid along the inner surface of the cold plate from the inlet channel to the outlet channel in a predetermined pattern that concentrates the flow of liquid through one or more predetermined high priority regions. The inlet channel is arranged such that when the cold plate assembly is arranged to cool the computing device, the inlet channel at least partially coincides with a high strength region of the computing device. The cold plate of the cold plate assembly can be 3D printed, which allows for a flexible cold plate design, which can be obtained by an iterative optimization method.

Description

Technical Field

[0001] The present invention relates to the liquid cooling of processing units of electronic devices, particularly computer devices, and how to design cold plate assemblies for individual computer chips. Background Art

[0002] As the power density of modern computing systems continues to increase, the effective cooling of electronic devices such as computers and servers has become very important. Due to the demand for greater computing power, the number of main heat sources in electronic devices such as central processing units or graphics processing units tends to increase. In addition, if the local temperature becomes too high, the computing device may be thermally suppressed. For these reasons, it is very important to be able to effectively cool the computing device and enable the electronic device to continue operating and perform complex tasks.

[0003] Auxiliary heat sources are cooled using passive cooling. This is done by using heat sinks whose size depends on the power density. When the power density increases, the heat sink becomes very large and thus is no longer practical, and another technology is needed.

[0004] For electronic devices with high power density, active cooling is used. Active cooling typically uses air cooling or liquid cooling. Air cooling uses fans and airflows to transfer heat away from the electronic device, so an efficient path for good airflow is needed. Since these electronic devices are closely packaged together, the airflow may be restricted by other devices, their cooling systems, and other internal structures, thus reducing the cooling efficiency. For this reason, liquid cooling is used to cool densely packaged electronic devices. Liquid cooling is a technology that can cool efficiently and occupy less space locally than air cooling.

[0005] For liquid cooling, a cold plate is used to exchange and carry away heat from the device to be cooled. Then, the heat is exchanged to the liquid inside the cold plate and is transported to the radiator, where the liquid is cooled and ready to be pumped back to the cold plate again to cool the cold plate again. Since the heat capacity of many liquids is much larger than that of air, liquid is used for cooling.

[0006] In a liquid cooling system, it is difficult to produce an effective heat exchange from the cold plate to the liquid. This needs to be done without losing too much pressure through the system while maintaining a high enough liquid flow rate. The surface area of the channels in the cold plate is the location where heat is exchanged from the cold plate to the liquid. The larger the surface area, the better the heat transfer. As the surface area of the channels in the cold plate increases, the flow resistance also increases, which limits the flow rate through the cold plate. There are more parameters that affect the cooling of the cold plate, such as the placement and size of the channels and grooves, the number of channels and grooves, and the material.

[0007] Previous liquid cooling was accomplished by cooling the entire cold plate, as disclosed in, for example, EP3907584A1.

[0008] The invention disclosed in EP3907584A1 is a cold plate assembly for use in a liquid cooling system for cooling a computing device, and it includes a method that comprises:

[0009] - Providing a thermal map of a computing system having at least two different electrical components spaced apart from each other and having two different heat generation rates, the thermal map mapping the associated heat generation of the at least two electrical components and their associated positions,

[0010] - Providing a template cold plate assembly design,

[0011] - Modifying the template design by mutually adjusting parameters related to an inlet manifold, inlet channels, chambers, fins, outlet channels, and an outlet manifold to achieve a cooling distribution on an outer surface of the cold plate that matches the thermal map of the computing system, and

[0012] - Producing a cold plate assembly according to the modified template design.

[0013] Known cold plates are designed to direct a liquid flow uniformly over the area to be cooled at an optimized rate. However, once the liquid has passed through the warmest area and its temperature has increased, the cooling efficiency decreases, thus reducing the efficiency of the cooling effect and making it inefficient for tightly packaged heat-generating components with non-uniform heat generation. Summary of the Invention

[0014] A first aspect of the present disclosure is:

[0015] A cold plate assembly for use in a liquid cooling system for cooling a computing device having a plurality of operating regions from which heat diffuses with a varying intensity from one or more high-intensity regions to one or more low-intensity regions, the cold plate assembly comprising:

[0016] A cold plate for exchanging heat between the computing device and a cooling liquid of the liquid cooling system, the cold plate including an outer surface for facing the computing device and an opposite inner surface adapted to contact the cooling liquid, the inner surface further including guiding means for guiding the cooling liquid along the inner surface in a predetermined pattern that causes the liquid flow to concentrate through one or more predetermined high-priority regions;

[0017] A distribution layer configured to be mounted on the inner surface of the cold plate, the distribution layer comprising:

[0018] - A liquid inlet through which the inner surface of the cold plate receives cooling liquid from the liquid cooling system, and

[0019] - A liquid outlet through which the cooling liquid is discharged from the inner surface into the liquid cooling system,

[0020] The liquid inlet is in liquid communication with an inlet channel, and the inlet channel and the liquid outlet are in liquid communication with an outlet channel,

[0021] such that the liquid flow is guided from the inlet channel through the cold plate to the outlet channel by the guiding means, and the inlet channel is arranged such that when the cold plate assembly is arranged to cool the computing device, the inlet channel at least partially coincides with the high-intensity region of the computing device.

[0022] Thus, the heat from the computing device is transferred to the cooling liquid. One factor facilitating efficient heat transfer is the guiding means that provides a large surface area for the cold plate to transfer heat. By cooling the computing device, the computing device can perform more tasks without the risk of overheating of the working components, so it can run faster.

[0023] A computing device is understood to be a device including one or more chips. A computing device can include, for example, an electronic circuit. A computing device can be a single working component, or it can be an integrated circuit including multiple working components. Such a computing device generates heat when processing data. For many computing devices, the generation of heat is not uniform. For example, in an integrated circuit, there will be a spacing between the working components of the chips, and no heat is generated in such a space. The location on the computing device where heat is generated is described as the working area. Heat will diffuse from such a working area to the entire computing device.

[0024] A high-intensity region is understood to be a region of the computing device corresponding to the high temperature generated by the working area. Thus, the high-intensity region may coincide with the working area. Therefore, high intensity is understood as high heat flux. For different embodiments of the present invention, the range considered to be high intensity can vary. A high-intensity region is understood to be a region within the highest predetermined portion of the heat flux found on the computing device. For example, in some variants, the high-intensity region can include regions where the heat flux is within the highest 10% of the heat flux of the computing device.

[0025] The low-intensity region is understood to be the region of the computing device corresponding to the region where the computing device generates little heat. Thus, the low-intensity region may be located at a position remote from the working region of the computing device or may coincide with a working region that generates less heat than other working regions of the same computing device. The low-intensity region is understood to be the region within the lowest predetermined portion of the heat flux found on the computing device. For example, in some variations, the low-intensity region may include the region where the heat flux is within the lowest 50% of the heat flux of the computing device.

[0026] The guiding device is understood to be any form of one or more channels that can guide a liquid flow through the guiding device. The guiding device may be a straight channel or a curved channel such that the guiding device has an arbitrary shape. An example of the guiding device may be a microchannel as they can guide a liquid flow. Hereinafter, the guiding device and the microchannel will be used interchangeably.

[0027] In a variation of the cold plate assembly, when the cold plate assembly is arranged to cool a computing device, at least one of the one or more predetermined high-priority regions coincides with one of the one or more high-intensity regions of the computing device.

[0028] By making the high-priority regions coincide with one or more of the high-priority regions, the cooling will be concentrated on the regions that generate the most heat.

[0029] In a variation of the cold plate assembly, when the cold plate assembly is arranged to cool a computing device, at least one of the one or more predetermined high-priority regions coincides with the working region of the computing device.

[0030] By making the high-priority regions coincide with the working region of the computing device, it is ensured that the most cooling occurs in the regions where heat is generated and in the regions where there are electronic components that can be protected by cooling.

[0031] In a variation of the cold plate assembly, the high-intensity region and the low-intensity region will be defined such that they cover all regions of the computing device. For example, the high-intensity region includes the region where the heat flux is within the 10% highest temperature flux of the computing device. Thus, the low-intensity region must include all regions where the heat flux is within the 90% lowest heat flux of the computing device. In other variations, there may be additional intermediate-intensity regions.

[0032] It should be understood that although the working region is the working region of the computing device, the high-intensity region and the low-intensity region can be mapped into the cold plate because when the outer surface of the cold plate contacts the computing device, the cold plate in contact with the computing device to be cooled will experience the same spatial distribution of heat flux.

[0033] To define how much cooling is required for each area of a computing device, priority areas are used. A high-priority area is an area that needs to be cooled as much as possible; this means that the maximum temperature or the average temperature should be minimized. A low-priority area is an area where the temperature needs to be kept below a specific temperature threshold. Different low-intensity areas can be defined by having different temperature thresholds. It can be that if the temperature exceeds, for example, 70 °C, a specific electrical part of the computing device may malfunction. In most cases, one or more high-priority areas will match one or more high-intensity areas, as these are the areas where the most heat is dissipated from the computing device. If, for example, at the location of sensitive electrical components or at components where the cooler they are, the better they perform, the high-priority areas can be placed within the low-intensity areas.

[0034] By having guiding means passing through the high-intensity area and placing the inlet channels at least partially on top of the high-intensity area, heat is effectively transported away from the working area, while less heat is transported away from other areas. An effective differential cooling system is produced.

[0035] The distribution layer ensures that the liquid enters through the inlet and is distributed from there. In addition, the distribution layer helps to make the system liquid-tight to prevent leakage.

[0036] Variations of the cold plate assembly include multiple inlet channels connected into an inlet network and / or multiple outlet channels connected into an outlet network. By having multiple inlet channels, cold liquid can be introduced close to the high-priority areas for effective cooling. Another effect is that the liquid flow path can be made shorter, resulting in less flow resistance and faster liquid flow.

[0037] Having multiple outlet channels helps to maintain a short liquid flow path and enables the hot liquid to be transported away from the high-priority areas.

[0038] In a variation of the cold plate assembly, the inlet network and the outlet network are connected via microchannels.

[0039] By having microchannels, the cold plate has a large surface area for transferring heat from the cold plate to the liquid, thus ensuring good heat transfer between the cold plate and the cooling liquid.

[0040] In a variation of the present invention, the cold plate assembly includes inlet channels and outlet channels arranged on opposite sides of the locally highest temperature part of the working area.

[0041] By placing the inlet channel and the outlet channel on opposite sides of the locally hottest part, cooling of the region with the local temperature maximum is ensured as the liquid passes through the microchannel between the inlet channel and the outlet channel. Additionally, placing them on opposite sides (i.e., adjacent to the hottest part rather than exactly coinciding with the hottest part of the temperature) ensures that at least a portion of the area to which heat radiates is cooled, which is relevant since the cold plate conducts temperature and thus heat will spread in all directions around the hottest part.

[0042] In a variant of the present invention, the cold plate assembly has at least one inlet channel including a constriction such that by gradually reducing and / or stepwise reducing the cross-sectional area of the inlet channel, the cross-sectional area is larger at a first position than at a second position.

[0043] By having a constriction in the form of a tapered cross-section in the inlet channel or by having a stepped cross-section, the cooling of the computing device can be manipulated in a controlled manner. This is because the flow resistance increases as the channel size decreases. Thus, the liquid flow rate can be controlled such that the flow rate is higher in some regions than in others. This can be used to cool high-priority regions more than other regions (e.g., low-priority regions).

[0044] In a variant of the present invention, the cold plate assembly has an inlet channel included in both the distribution layer and the cold plate and / or an outlet channel included in both the distribution layer and the cold plate.

[0045] When the inlet channel is included in both the cold plate and the distribution layer, it is easier to design the system and make it liquid-tight.

[0046] In a variant of the present invention, all microchannels are arranged as part of the cold plate.

[0047] The microchannels can be arranged such that the heat transfer from the cold plate to the liquid is maximized. For example, if the heat transfer capacity of the cold plate is better than that of the distribution layer, it may be beneficial to confine the microchannels to the cold plate. Having microchannels only in the cold plate can also more protect the cold plate assembly from liquid leakage.

[0048] In a variant of the present invention, the cold plate assembly includes a plurality of microchannels and / or inlet channels and / or outlet channels, which are arranged in a plurality of layers superposed on one another with respect to the outer surface of the cold plate.

[0049] By having a plurality of channels superposed on one another, better heat transfer can be obtained. The freer placement of the channels can also shorten the flow path.

[0050] In one variant, the cold plate assembly includes one or more microstructures that project at least partially transversely to the direction of liquid flow in one or more microchannels.

[0051] By having microstructures protruding within the microchannels, the surface area of the cold plate can be increased, and the increased surface area can result in improved heat transfer. Additionally, the microstructures can introduce turbulence within the channels, which in turn can enhance heat transfer to the cooling liquid.

[0052] In a variant of the present invention, the cold plate assembly has a cold plate constructed via 3D printing.

[0053] 3D printing is a very versatile technology that can construct many different shapes. It provides the possibility to design and optimize heat transfer for all channels. The channels can include bends through which the liquid flows and / or a lattice of metal. Introducing a lattice within the flow path can improve heat transfer because the contact surface area between the cold plate and the liquid increases. Introducing bends and irregular shapes can be used to control the flow resistance. By designing each channel, cooling can be differentiated to suit many different computing devices.

[0054] A second aspect of the present disclosure is:

[0055] A method of designing a cold plate assembly, which includes the following steps:

[0056] Obtain a surface temperature distribution map of the target computing device,

[0057] Define a fixed inlet position and a fixed outlet position of the cold plate assembly,

[0058] Iteratively optimize the placement and / or number and / or size of the inlet channels, outlet channels, and / or microchannels of the cold plate assembly so as to minimize the temperature simulated based on the surface temperature distribution map of the combined system of the cold plate assembly and the computing device.

[0059] In a variant of this method, the temperature minimized during optimization is the overall temperature maximum or the average temperature, such as the total average or the average temperature of the region corresponding to the highest 10% temperature range of the temperature distribution map.

[0060] In one variant, the method further includes the following steps:

[0061] Based on the surface temperature distribution map, define multiple priority regions according to the predetermined temperature limits of each priority region,

[0062] Before optimizing the cold plate assembly, divide the multiple priority regions into at least two categories according to the highest surface temperature of each region, one of the at least two categories being the high-priority region such that at least one high-priority region is allocated, and

[0063] Define the high-priority region as the temperature minimization region.

[0064] By dividing the area of the cold plate assembly into high-priority areas and low-priority areas, it is selected which areas of the computing device are important to cool and which areas are less important.

[0065] In a variant of the method, the area of the cold plate is defined as a high-priority area such that the high-priority area covers the entirety of the heat map.

[0066] If the overall highest temperature of the computing device is to be minimized, a high-priority area covering the entirety of the heat map can be used. The high-intensity area can have a criterion for minimizing the overall highest temperature within that area. This can be done using a single function that describes the heat map, i.e., a function that describes the two-dimensional variation of the heat flux over the area of the computing device (if such a function is available). If the heat map is described by multiple functions, the area of the heat map can be divided into multiple priority areas. The description by multiple functions can also include the discretization of the heat map and the assignment of values indicating the relevant heat flux to each pixel of the heat map, i.e., discrete segments.

[0067] In other words, variants of the method for designing a cold plate assembly include all of the following steps:

[0068] Obtain a surface temperature distribution map of the target computing device,

[0069] Based on the surface temperature distribution map, define multiple priority areas according to the predetermined temperature limits of each priority area,

[0070] Divide the multiple priority areas into at least two categories according to the highest surface temperature of each area, one of the at least two categories being a high-priority area such that at least one high-priority area is assigned,

[0071] Define a fixed inlet position and a fixed outlet position,

[0072] Iteratively optimize the position and / or number and / or size of the inlet channels, outlet channels, and / or microchannels to minimize the temperature in the at least one high-priority area.

[0073] In a variant of the method, one of the at least two categories is a low-priority area such that at least one low-priority area is assigned, wherein the optimization is restricted to keeping the highest temperature in the low-priority area below a predetermined threshold.

[0074] To differentiate the cooling of a computing device, it is important to have areas where cooling is less important than in high - priority areas. This is done by having low - priority areas where the temperature is kept below a certain threshold. The threshold can be selected to ensure that no part of the computing device overheats, for example, based on what the maximum operating temperature is acceptable for the computing device. For different areas, the threshold can be set differently, and the importance of each area can be selected.

[0075] In a variant of the method that includes more than two categories, the categories are hierarchically ordered, with the highest category in the hierarchy being the high - priority area, and each other category being assigned a different predetermined threshold, so that the predetermined threshold for temperature is highest for the area lowest in the hierarchy.

[0076] By having different thresholds, the cooling importance of areas can be differentiated.

[0077] In a variant of the method, the high - priority area includes at least one local temperature maximum of the surface temperature distribution map.

[0078] By having a local temperature maximum in the high - priority area, it is ensured that the cold plate is constructed to cool most effectively in the highest - temperature area. Additionally, it is ensured that the high - priority area is placed in the working area of the computing device.

[0079] In a variant of the method, the fixed positions of one or more inlet channels are also predetermined.

[0080] By fixing one or more inlet channels, the position where the fluid will enter the cold plate can be controlled. Thus, if the symmetry of the heat map makes it simple to place the inlet channels near the temperature maximum on the heat map, this can make the optimization faster and better. On the other hand, it can be that the inlet channels are subject to mechanical limitations and thus need to be in fixed positions.

[0081] In an alternative variant, the method includes predetermining the fixed positions of at least two inlet channels.

[0082] The following specific examples according to aspects of the present disclosure will be explained in more detail with reference to the accompanying drawings. However, the present disclosure can be embodied in forms different from those depicted below and should not be construed as limited to any of the examples set forth herein. Instead, any example is provided so that the present disclosure is thorough and complete and will fully convey the scope of the invention to those skilled in the art. The same reference numerals always refer to the same elements. Therefore, the same elements will not be described in detail with respect to the description of each figure. Brief Description of the Drawings

[0083] Figure 1 An assembled cold - plate assembly is shown.

[0084] Figure 2 Shows a dual CCD CPU chip.

[0085] Figure 3 Shows a Figure 2 thermal map obtained from the CPU chip shown.

[0086] Figure 4A Shows Figure 2 the optimized flow path design of the CPU chip shown.

[0087] Figure 4B Shows the optimized flow path design of a CPU chip with four CCDs and one IOD.

[0088] Figure 5A Shows an example of a cold plate designed with microchannels.

[0089] Figure 5B Shows Figure 5A a magnified close-up on the cold plate in

[0090] Figure 5C Shows the Figure 5A cold plate as viewed from below.

[0091] Figure 6A Shows a distribution layer placed on top of the cold plate.

[0092] Figure 6B Shows the distribution layer as viewed from below.

[0093] Figure 7 Shows a cross-section of the cold plate assembly.

[0094] Figure 8 Shows a cross-section of a microchannel with microstructures inside.

[0095] Figure 9 Shows a cross-section of a microchannel with cylinders inside.

[0096] Figure 10 Shows microchannels made into a 3D lattice.

[0097] Figure 11 Shows the arrangement of channels for guiding flow diversion.

[0098] Figure 12 Shows the arrangement of channels for guiding flow confluence.

[0099] Figure 13 Shows the arrangement of channels for guiding direct current.

[0100] Figure 14 Shows an alternative arrangement of channels for guiding direct current.

[0101] Figure 15 Shows an example heat map of a cold plate design including a split and two merges, as well as the components to be cooled. Detailed implementation

[0102] Hereinafter, the present invention will be described in detail through embodiments of the present invention, and these embodiments should not be considered as limiting the scope of the present invention.

[0103] In Figure 1 an embodiment of the present invention can be seen. In the shown system, the cold plate assembly includes three parts: cold plate 105, distribution layer, and top layer 107. The system has an inlet 101 for cooling liquid to enter the cold plate assembly and an outlet 103 for guiding the cooling liquid out of the cold plate assembly.

[0104] The cold plate 105 is used for heat exchange between the computing device and the cooling liquid. The cooling liquid is understood to be any liquid that can be used in a liquid cooling system to transfer heat, such as water or a mixture of liquids having suitable properties regarding heat transfer, heat capacity, and thermal expansion, such as any coolant known to be suitable for a liquid cooling system. When the cold plate assembly is installed to cool a computing device, the cold plate 105 is arranged such that its outer surface is in thermal contact with the computing device to be cooled. The top layer 107 is used to receive the cooling liquid and guide it into the distribution layer and the cold plate 105. The top layer 107 is also adapted to guide the cooling liquid out of the cold plate and the distribution layer. The top layer can be composed of multiple parts. In a preferred embodiment, the top layer can have an outlet 103 and an inlet 101.

[0105] The distribution layer is used to distribute the cooling liquid into the cold plate and ensure a liquid-tight system. In some embodiments, the top layer 109 can be dispensed with, and the liquid inlet and liquid outlet can be directly arranged in the distribution layer. To drive the cooling liquid through the cold plate assembly, a pump can be used. The pump will circulate the cooling liquid in the cooling loop by sucking the liquid through the inlet pipe into the inlet opening 101 through the cold plate assembly to receive the thermal energy from the electronic device and coming out from the outlet 103 to be cooled at another location (usually in a liquid-air radiator or a liquid-liquid heat exchanger).

[0106] Fastening the cold plate assembly such that the outer surface of the cold plate is in thermal contact with the computing device can be accomplished by fastening from above against the top of the cold plate assembly using a conventional bracket or through an interface hole mounted on the printed circuit board (PCB) of the computing device. Alternatively, the cold plate assembly can have an integrated mounting interface to make it easy to install it onto a computing device such as a CPU. The cold plate assembly can have additional mounting means to facilitate a firm hold, such as using screws, which may be useful when installing the cold plate assembly onto a processing card or a graphics card, etc.

[0107] Figure 2FIG. 0 shows an example design of a computing device 200, which includes an Input / Output Die (IOD) 203, some Core Complex Dies (CCDs) 201, and may include some connections distributed across the computing device 200. The electrical components of the computing device use electrical energy to perform computing operations, and this process generates heat as a byproduct. This heat is mainly generated in some specific areas (i.e., the working areas of the computing device), but the temperature distribution strongly depends on how the cores are placed and may also depend on which tasks the cores are running. The present invention attempts to design a cooling system for cooling the chip in an efficient manner based on how much heat is generated in different areas on the chip. The computing device can be made in many different shapes and have different numbers of cores. Thus, Figure 2 is only one example of a computing device that the liquid cooling system of the present invention can be used to cool.

[0108] To identify where the computing device generates heat, the thermal distribution of a working computing device can be obtained by mapping the temperature distribution at different locations corresponding to the computing device. Such a mapping can be represented by a surface temperature map (also known as a heat map), which is a technique for visualizing data values in 2D. This is typically done by representing the data values with colors or grayscale. For the present invention, a temperature heat map is used. The temperature distribution can be obtained by measurement or simulation, or it can be provided by a third party. For example, an infrared camera can be used to measure an electronic device while it is performing tasks to record the electronic device. In the simulation of heat generation in an electronic device, the internal structure of the device can be used to estimate the heat generation when the computing device is operating. The heat map of the computing device can show the temperature rise in the working area of the device. The working area of the computing device is the area where at least part of the energy used for computing is converted into heat energy.

[0109] Similar to Figure 2 the heat map of a device similar to the Figure 3 device shown can be seen in Figure 3 The scale of the heat map shown is such that black represents the lowest temperature and white represents the highest temperature. If a pixel with white is inside the IOD 203 or CCD 201, it corresponds to a high temperature. If a pixel is white and placed outside the locations of the IOD 203 and CCD 203, it does not show data. In Figure 3In the example heat map, it can be seen that there are multiple local hottest parts 303 inside the CCD 201. The heat map shows that most of the generated heat is generated by the CCD 201 compared to the relatively small amount of heat generated by the IOD 301. The heat map can be divided into smaller regions each having a highest and an average temperature; these regions can be designated as high-intensity or low-intensity regions. Alternatively, these regions can be divided based on the highest and lowest temperatures occurring in the region.

[0110] An embodiment of the cold plate assembly according to the present invention is shown in Figure 4A . This figure shows the liquid flow and heat transfer through the cold plate. The cold plate is placed directly on top of the computing device to be cooled, with direct contact between the outer surface of the cold plate and the computing device. The cold plate can preferably be made of a material with high thermal conductivity, such as copper, aluminum, or other metals.

[0111] Figure 4A The embodiment shown is an optimized design of the cold plate assembly for providing effective cooling of a device (such as the Figure 2 device shown), i.e., for a CPU chip including two side-by-side CCDs spaced apart from the IOD. The arrows in the figure show the liquid flow, and the width of the arrow corresponds to the magnitude of the liquid flow rate. If the arrow is larger, the flow rate at that point is higher than that in the section with a smaller arrow.

[0112] In Figure 4A the embodiment shown, the liquid enters the distribution layer via the inlet 405, and the liquid is directed from the inlet 405 into three inlet channels 403 that are in fluid communication. These three inlet channels 403 form an inlet network, and the channels of the inlet network are in direct fluid communication. The sections of the inlet channel 304 are arranged parallel to each other. The inlet channel 403 is connected to the microchannel 401. The inlet channels can have different sizes to control the liquid flow rate through them. For example, contraction can be achieved by having a stepwise difference in the cross-sectional area of the channel. In another example, the contraction can take the form of at least a part of the channel gradually decreasing in size such that the channel is wider at a first position than at a second position. If the size of the channel decreases, the flow rate decreases. Figure 4A The middle inlet channel of the embodiment of Figure 4A includes a contraction section 404 with a reduced size; in

[0113] The microchannels 401 may also have different sizes to direct the flow of the cooling liquid, which in the figure is indicated by the width of the arrows depicting the microchannels 401.

[0114] The cold plate assembly includes liquid channels. The arrangement of these liquid channels can be divided into different liquid flow types, and particularly relevant are diverging flow, converging flow, and straight flow.

[0115] Diverging flow describes the liquid flow that branches from an inlet channel into multiple channels, where the branched channels direct the liquid flow away from the inlet channel in at least two directions. Figure 11 Diverging flow is shown, where the inlet channel is in liquid communication with a plurality of microchannels. The plurality of microchannels are arranged such that when the cooling liquid flow is directed from the inlet channel into the microchannels, the cooling liquid flow is separated, and the liquid flow 801 is directed to both sides of the inlet channel. In some preferred embodiments, the channels that direct the flow away from the inlet channel in multiple directions are microchannels. In some preferred embodiments, the diverging flow directs the liquid flow 801 away from the inlet channel in two opposite directions perpendicular to the inlet channel, as Figure 11 shown. The liquid flow can be divided from the inlet channel into any number of channels, such as two, three, four, five, six, or more channels. In some embodiments, multiple regions of the cold plate assembly include diverging flow.

[0116] In a preferred embodiment, when a region of the cold plate assembly includes an inlet channel fluidly connected to at least two outlet channels located on both sides of the inlet channel through a guiding device, this region of the cold plate assembly can be considered suitable for the diverging type of liquid flow, such that the cooling liquid flow is directed from the inlet channel to the outlet channels in a diverging manner.

[0117] An example of diverging flow is shown in Figure 4A and occurs when a portion of the liquid flow separates from the constricted section of the inlet channel 404 and is directed into a plurality of microchannels 401. As Figure 11 shown, the liquid flow can be divided from the inlet channel into a plurality of microchannels.

[0118] In a preferred embodiment, diverging flow can direct the cooling liquid to locations that require effective cooling, because the cold cooling liquid enters through the inlet channel and is distributed through the microchannels, where the cooling liquid is heated. The cooling liquid can be directed into the cold plate assembly through one or more inlets and distributed in the cold plate assembly through one or more diverging flows.

[0119] Converging flow describes a flow type in which a plurality of channels that direct the flow in different directions are connected such that the flow enters a single channel. In a preferred embodiment, the flow combines at multiple points along a single channel. In a preferred embodiment, the single channel can be an outlet channel. Figure 12Shows a confluent type of flow when the microchannels on both sides of the outlet channel are connected to the outlet channel. The liquid flow 801 is guided by the microchannels from each side of the outlet channel into the outlet channel. Any number of channels can be present that merge or combine the flows into a single channel. In some embodiments, the confluence is arranged such that the liquid flows are guided from opposite sides of the outlet channel in a perpendicular manner from multiple microchannels into the outlet channel, as Figure 12 shown. In some embodiments, multiple regions of the cold plate assembly include confluences.

[0120] In a preferred embodiment, when a region of the cold plate assembly includes an outlet channel that is fluidly connected to at least two inlet channels located on both sides of the outlet channel by guiding means, that region of the cold plate assembly can be considered suitable for a confluent type of liquid flow such that the cooling liquid flow is guided from the inlet channels to the outlet channel in a confluent manner.

[0121] As Figure 4A shown, when the microchannels 401 are fluidly connected to the same outlet channel 409 from both sides of the outlet channel 409, it can be an example of confluence. The guiding means can be defined as terminating at the location where they are fluidly connected to the outlet channel such that when multiple microchannels terminate in the same outlet channel from opposite sides of that outlet channel, an outlet flow occurs. Embodiments of the cold plate assembly according to the present invention can include any number of outlet channels. Additionally, the outlet channels can include sections of different flow types, for example, a section having a split flow and another section having a confluent type of flow. In some embodiments, the outlet channel can be only in the cold plate of the assembly. In other embodiments, the outlet channel can be located in the cold plate and the distribution layer. The outlet channel can be connected to one or more outlets in the distribution layer. The positioning of the confluence in the cold plate assembly can depend on the location of the outlet channel arrangement and the connection points where the microchannels enter the outlet channel. The location of the confluence can depend on the location where the computing device generates heat. The confluence can be a type of flow in a region of the cold plate assembly. The region having a confluence can be different from the region having a split flow. In a preferred embodiment, the cold plate assembly includes one or more regions having a confluence and one or more regions having a split flow. In some preferred embodiments, one or more split regions are different from and separate from the confluence regions.

[0122] The confluence can merge the heated cooling liquid into fewer channels to effectively guide the heated cooling liquid away from the cold plate. Since the heat from the computing device is most effectively transferred to the cooling liquid in the microchannels, the cooling liquid can be hot when leaving the region having a confluence.

[0123] DC describes a situation where a liquid flow is directed from a first channel to a second channel through multiple channels in the same direction. For example, this could be multiple channels that split from one channel and merge into a second channel in the same direction. Figure 13 An example of DC is shown, where an inlet channel is connected to an outlet channel through multiple microchannels that direct the liquid flow from the inlet channel to the outlet channel in parallel in the same direction. The microchannels enter the outlet channel and the liquid flows merge in the outlet channel. This provides a flow in the same direction over an area and is thus represented as DC. In Figure 14 Another example of a DC type of flow is shown, where in this case the liquid enters in the middle of the inlet channel such that the flow expands in opposite directions in the inlet channel, then expands in the same direction in the microchannels, and then combines again into a single flow.

[0124] The cooling efficiency of a computing device can depend on the distribution and connection of the channels and thus on the type of flow used in the cold plate assembly and the location of these types of flows.

[0125] In one embodiment, at least a portion of the inlet channel is located above a high-intensity area of the computing device, and the microchannels exiting the inlet channel exit from the edge of the inlet channel that overlaps the high-intensity area. This can be achieved by having the split at least partially overlap the high-intensity area.

[0126] In one embodiment, the inlet channel and the connected outlet channel are located on opposite sides of a high-intensity area of the computing device, and the cold plate assembly is designed to cool this high-intensity area. The inlet channel and the outlet channel can be positioned such that they are on either side of the hottest part in the high-intensity area. The inlet channel can overlap the high-intensity area. The outlet channel can overlap the high-intensity area. The inlet channel can overlap the hottest part of the computing device. Alternatively, the inlet channel can be positioned adjacent to the hottest part of the computing device.

[0127] The microchannels of the cold plate can all have the same size. The microchannels of the cold plate can have two or more different sizes to provide varying flow rates in different areas, for example, a higher cooling liquid flow rate in one area and a lower cooling liquid flow rate in another area.

[0128] The openings (such as inlets and outlets) of the distribution layer can be optimized to cool the computing device. Optimizing the cooling can be performed in different ways. The openings can be located close to the high-intensity area of the computing device. More specifically, the openings of the distribution layer can be located near one or more of the hottest parts of the computing device. The openings of the distribution layer can be represented as inlets and / or outlets. The distribution layer can have one or more inlets and one or more outlets.

[0129] The cold plate assembly may include a confluence by including an outlet channel through which the cooling liquid can enter from both sides from the microchannels. This can be perpendicular to the side of the outlet channel such that when entering the outlet channel from the microchannels, the direction of the liquid flow is changed by 90°. When the liquid can enter the outlet channel from both sides, the outlet channel can be positioned between two inlet channels. The outlet channel can be placed in the middle between the two inlet channels (i.e., such that the spacing between the outlet channel and each adjacent inlet channel is equal), or placed at any position between the two inlet channels such that the microchannel from one inlet channel to the outlet channel is shorter than the microchannel from the other inlet channel to the outlet channel. The outlet channel can be arranged at any position in the cold plate assembly. The outlet channel can at least partially overlap with the working area of the computer chip. The outlet can at least partially overlap with the high-intensity area. The outlet can be arranged between two high-intensity areas. The outlet can be arranged in the low-intensity area. The outlet can be arranged between the two local temperature maxima of the computer chip. As Figure 4A shown, the end point 409' of each of the two outlet channels 409 is located between three inlet channels 403. One or more inlet channels can be located at any position in the cold plate assembly. This can be outside the area of the cold plate assembly for cooling the computing device, or within the area of the cold plate for cooling the computing device. One or more inlet channels can be positioned to partially overlap with the working area of the computing device. One or more inlet channels can be positioned to partially overlap with the high-intensity area of the computing device. One or more inlet channels can be positioned to partially overlap with the temperature maximum point / area of the computing device. Placing the outlet channel between two inlet channels can provide optimized cooling of the computing device. One reason for the improved cooling may be that the working components of computing devices such as CCDs, IODs, etc. typically generate the most heat at the edges of the components. Therefore, it may be advantageous to place the microchannels over these heat-generating areas, where the inlet is close to or overlaps with the heat-generating area.

[0130] To provide the most effective cooling, the flow type of the cold plate can be positioned according to the heat-generating area and the non-heat-generating area.

[0131] A computing device may have a first working area and a second working area that generate heat. The two working areas may be separated from each other. The first working area may be cooled by a first flow type, which is any one of a split flow, a combined flow, or a direct flow, and the second working area may be cooled by a second flow type, which is any one of a split flow, a combined flow, or a direct flow. The first flow type and the second flow type may be different flow types. For example, the first flow type is a split flow, and the second flow type is a combined flow or a direct flow. The first flow type and the second flow type may be the same flow type. For example, both are split flows or both are combined flows. By having a first flow type in the first working area and a second flow type in the second working area, the computing device can be cooled in two different ways or two similar ways. This can provide optimal cooling for computing devices with similar or different working areas and working components. If a split flow is one of the two flow types, the split flow may be located at the edge or the center of the working area. If one of the two flows is a combined flow, the combined flow may be located at the center of the working area.

[0132] Figure 4A The cold plate assembly of the illustrated embodiment further includes two outlet channels 409. The outlet channels 409 are arranged such that when the cold plate assembly is mounted on a target computing device, the outlet channels will be arranged to contact a low thermal energy region. One or more sections of each outlet channel 409 are arranged parallel to one or more sections of at least one inlet channel.

[0133] The microchannels 401 are connected to the outlet channels 409 and the inlet channels 403 such that liquid can flow from the inlet channels 403 through the microchannels 401 into the outlet channels 409. The outlet channels 409 are connected to at least one outlet 407. The liquid flows out of the outlet 407, and the liquid is directed away from the outlet 407 to be cooled outside the cold plate assembly and then pumped back into the inlet 405 again.

[0134] In some embodiments, the spacing between the microchannels may be different at different regions of the cold plate. For example, it may be different in the region to be mounted on top of the target IOD 203 or CCD 201 or in the region without a working area.

[0135] In Figure 4AIn the illustrated embodiment, the channels are formed in a combination of the cold plate and the distribution layer. In some embodiments, all of the microchannels are formed in the cold plate, while the inlet and outlet channels are formed in the distribution layer. In other embodiments, all of the microchannels are formed in the cold plate, while at least a portion of the inlet and outlet channels are formed in the distribution layer and a portion of the inlet and outlet channels are formed in the cold plate. In all embodiments, there will be microchannels in the cold plate. Additionally, the inlet and outlet channels will pass through the distribution layer.

[0136] In a preferred embodiment, the cold plate assembly includes two or more different flow regions having at least two different flow types, i.e., the first flow region is a diverging type and the second flow region is a converging type.

[0137] In a preferred embodiment, the cold plate assembly includes one or more outlet channels that can be branched such that each branch is arranged to direct a continuous flow of cooling liquid in the same flow direction. In a preferred variant of this embodiment, at least one branch of the outlet can be divided into two or more outlet segments along the flow direction of the branch of the outlet channel such that at least two segments are configured to receive cooling liquid of two different flow types. For example, a first segment of the branch of the outlet channel is configured to receive cooling liquid in a diverging configuration, while a second segment of the same branch of the outlet channel is configured to receive cooling liquid in a converging configuration. An example of this case is shown in Figure 4A which shows that the rightmost branch of the outlet 409 initially has a segment in a converging configuration near the endpoint 409', and later along the flow direction (i.e., closer to the outlet 407), the outlet channel 409 has a segment for receiving liquid from the diverging flow placed on top of the region 203. The regions having two different flows may not overlap such that the diverging outlet channel also receives cooling liquid in the same region or at the same position along the outlet channel in the opposite direction, i.e., the outlet channel cannot support both diverging and converging simultaneously. Thus, the two regions having two flow types can be two separate regions.

[0138] Another embodiment of the present invention is shown in Figure 4B which shows a design of a cooling system for a computing device having four CCDs 201 and one IOD 203. The IOD 203 is drawn as a rectangle in the middle of the figure, and the CCDs 201 are also drawn as rectangles arranged adjacent to each other on opposite sides of the IOD 203, thereby forming a structure that is mirror symmetric along two vertical axes centered on the IOD. The drawn channels show the channels formed by the cold plate and the distribution layer. The arrows show the liquid flow existing only within the channels. The liquid flow in the microchannel 401 is shown by the arrow 401.

[0139] InFigure 4B In the illustrated embodiment, liquid enters through two inlets 405. The liquid is distributed from the inlets into six inlet channels 403. The liquid may flow from the inlet channels 403 into the microchannels 401. The microchannels extend between the inlet channels 403 and the outlet channels 409 of the cooling system. The liquid may flow out through the outlet channels 409 until it reaches one of the two outlets 407. In this embodiment, at least a portion of some of the inlet channels 404 has an end that is smaller than the first end of the inlet channel, where the first end of the inlet channel is the end of the inlet channel into which the liquid flow enters, i.e., the end connected to the inlet 405. As the cross-sectional area of the channel gets smaller, the flow rate decreases.

[0140] Generally speaking, the present invention can have many different embodiments with different shapes and features. What these embodiments have in common is that they can include one or more inlets and one or more outlets for a cold plate assembly. Additionally, the cold plate assembly can include one or more inlet channels and one or more outlet channels in addition to the plurality of microchannels. One or more inlet channels can be in direct fluid connection / communication with one or more inlets. Direct fluid connection is understood to mean that the fluid communication between two channels is not transmitted through another set of pipes or channels. If two components are in direct fluid connection, it should be understood that the two components are directly connected. The inlet channels can be in direct fluid contact with the microchannels. The microchannels can be in direct fluid contact with the outlet channels. In such a configuration, the inlet channels and the outlet channels can be in indirect fluid communication via the microchannels. The outlet channels can be in direct fluid contact with the outlets. The outlets, inlets, outlet channels, inlet channels, and microchannels can be formed by a cold plate, a distribution layer, a top layer, can be formed in only one of these layers, or can be formed in a combination of these three layers. The inlet channels can include constrictions such that the cross-sectional area of the inlet channels decreases, for example by gradually decreasing through stepwise changes.

[0141] A part of the present invention is a method for designing a cold plate assembly that effectively and differentially cools a specific computing device. Differential cooling can be understood when the system is designed to convey away more heat from certain parts of the cold plate than from other parts. When generating a design for a specific cold plate, there are many important parameters, some of these parameters are: the pressure of the liquid, the size of the microchannels, the number of microchannels, the shape of the microchannels, the temperature of the cooling liquid, the flow rate of the cooling liquid, the flow resistance in the system, the number and placement of the inlet and outlet slots.

[0142] To design a cold plate assembly with optimized cooling, a heat map is divided into smaller regions based on heat generation in the region, and these regions are called intensity regions as described above. Thereafter, each intensity region is divided into at least two categories, namely high-priority regions or low-priority regions. A high-priority region is defined as a region where the optimization goal is to reduce the highest temperature to as low as possible. The criterion for a high-priority region can alternatively be to reduce the average temperature of the region to as low as possible.

[0143] A low-priority region is defined such that the optimization goal is for the highest temperature in the region to remain below a defined threshold temperature. For a low-priority region, the criterion can also be that the average temperature should be below the threshold.

[0144] If desired, all intensity regions can be classified as high-priority regions such that there are no low-priority regions. If the heat map can be described by a single function, the overall temperature maximum of the entire heat map can be minimized as if it were a high-priority region. If the heat map is described by multiple functions and / or by a division of discrete regions, this may be more difficult. The heat map can be divided into multiple intensity regions to provide more control over the optimization, especially for cases where the heat map is described by more than a single function.

[0145] In some embodiments, the high-priority regions can coincide fully or partially with the high-intensity regions of the heat map. In other embodiments, one or more high-priority regions can be located elsewhere relative to the target computing device, for example, above a working area with special cooling requirements, even if it generates less heat than other working areas of the computing device.

[0146] Subdivisions of other categories of intermediate-priority regions or low-priority regions can have conditions that require the temperature to be maintained within a range, for example, 20 - 50 °C. By introducing multiple threshold temperature values for the low-priority regions, these low-priority regions can be divided into multiple low-priority categories. These categories can be hierarchically ordered such that the high-priority regions are highest in the hierarchical structure. The low-priority region with the highest threshold temperature is lowest in the hierarchy, and the low-priority region with the lowest threshold is higher in the hierarchical structure than the other low-priority regions but lower than the high-priority regions in the hierarchical structure. An example of such a hierarchical structure has three regions: a low-priority region with a threshold of 40 °C, a high-priority region, and a low-priority region with a threshold of 60 °C. The optimized hierarchical structure for these three regions will first have the highest priority: the high-priority region where the optimization goal is to minimize the temperature, the low-priority region with a threshold of 40 °C, and the low-priority region with a threshold of 60 °C.

[0147] A method of designing a cold plate assembly includes the following steps:

[0148] ·Obtain a heat map of the computing device to be cooled, i.e., a mapping of the heat flux of the computing device.

[0149] ·Divide the heat map into smaller regions and classify these regions as high-intensity regions or low-intensity regions based on how much heat is generated in the region.

[0150] ·Classify all intensity regions based on the desired cooling of the computing device such that each region belongs to one of the following categories: high-priority region, low-priority region. In this process, at least one intensity region should be assigned as a high-intensity region.

[0151] ·Define the positions of the inlet and outlet of the cold plate assembly.

[0152] ·Place the inlet channels, outlet channels, and microchannels. This can be done by an initial guess or by a full optimization using a computer program.

[0153] ●Perform iterative optimization of the positions, numbers, and dimensions of the inlet channels, microchannels, and outlet channels. At each step, calculate the heat flux and optimize the system to minimize the temperature in at least one high-priority region.

[0154] In a preferred variant, the method will result in the inlet channels being positioned such that they partially coincide with the high-intensity regions. This means that the projection of the inlet channels onto the computing device will overlap at least some of the regions of the high-intensity regions.

[0155] In a method for obtaining a cold plate assembly optimized for a specific computing device, different parameters can be specified for the specific cold plate assembly such that it provides optimal cooling for the specific computing device. As described in the previous section, the parameters of the optimized cold plate assembly can be at least the number of flow types, flow type positions, flow type combinations, number of inlets, inlet positions, inlet dimensions, number of outlets, outlet positions, outlet dimensions, number of inlet channels, inlet channel positions, height and width of the inlet channels, number of outlet channels, outlet channel positions, height and width of the outlet channels, constrictions in the inlet and outlet channels, number of microchannels, microchannel positions, width and height of the microchannels, thickness of the walls between the microchannels.

[0156] The type of flow required for a particular cold plate assembly to cool a particular computing device can be the first parameter determined when optimizing the design of the cold plate assembly. The type of flow can be determined based on a heat map of the particular computing device. The type of flow can be determined as direct flow and / or split flow and / or confluent flow. Different regions of the computing device can be optimally cooled by a particular type of flow. For example, high-intensity regions tend to be heated substantially, so a split flow with cold coolant in that region may be optimal. This is just one example, and there may be many different locations where split flow may be optimally used. The split flow can be positioned near a high-intensity region or between two high-intensity regions.

[0157] Additionally, to determine which types of flow should be used and where they should be located in the cold plate assembly, other parameters can be determined that describe how to form the distribution layer. These parameters can be the number of inlets, the number of outlets, the location of the inlets, the location of the outlets, the shape of the inlets, the shape of the outlets, the shape of the distribution layer, and the location and shape of the channels in the distribution layer. These parameters can be determined based on a heat map of the particular computing device.

[0158] The parameters can be determined based on the heat map in order of priority:

[0159] 1. The type of flow.

[0160] 2. The location, size, number, and shape of the inlets and outlets in the distribution layer.

[0161] 3. The size, location, shape, and number of channels in the cold plate assembly, such as inlet channels, outlet channels, and microchannels.

[0162] Each of these parameters can be determined by starting with an initial guess and optimizing, or can start without any guesses about the parameters, and a computer program can be used to optimize all the parameters using an algorithm, or the parameters can be determined manually. The manually determined parameters can be used to ensure that the cold plate assembly can be manufactured or has particular desired characteristics.

[0163] In a method for obtaining a cold plate assembly, the method can include the following steps or only some of the following steps:

[0164] ● 602 Obtain a heat map of the computing device to be cooled, i.e., a mapping of the heat flux of the computing device.

[0165] ● 604 Determine the type of flow to be used in the cold plate assembly based on the heat map.

[0166] ● 606 Determine the location of at least one split flow and the location of at least one confluent flow in the cold plate assembly to provide optimal cooling of the computing device based on the heat map.

[0167] ·608 Determine the locations of all flow types for use in a cold plate assembly based on a heat map.

[0168] ·610 Determine the number, size, shape, and location of the inlets and outlets of the distribution layer based on the heat map such that these parameters are suitable for the specific flow types obtained in all previous steps.

[0169] ●612 Determine the size, location, shape, and number of channels in the cold plate based on the heat map such that these parameters are suitable for the specific flow types obtained in the previous steps.

[0170] Any step can be done by an initial guess or by full optimization using a computer, which may be using an algorithm running on a computing device.

[0171] The following steps can be part of the method:

[0172] ·614 Divide the heat map into smaller regions and classify these regions as high-intensity regions or low-intensity regions based on how much heat is generated in the region.

[0173] ·616 Classify all intensity regions based on the desired cooling of the computing device such that each region belongs to one of the following categories: high-priority region or low-priority region. In this process, at least one intensity region should be assigned as a high-intensity region.

[0174] ·618 Define the locations of the inlets and outlets of the cold plate assembly.

[0175] ·620 Perform iterative optimization of the flow type, location, number, and size of the inlet channels, microchannels, and outlet channels. In each step, calculate the heat flux and optimize the system to minimize the temperature in at least one high-priority region.

[0176] All steps can be optional and their order of execution does not need to be as listed here, so the steps can be performed in any order.

[0177] The order of steps in method 600 can be as listed here and the steps may need to be performed in a sequential order.

[0178] When determining the locations of elements of similar channels, this can be done by optimization using a computer. This optimization can minimize the maximum temperature, the average temperature within a given region. Different criteria may exist for different regions.

[0179] An example of a cold plate obtained by method 600 is in Figure 15Shown in. The resulting design includes one split and two merges. The microchannels 401 merge when combining the flows into the outlet channel. One or more inlet channels may be positioned to partially overlap the high-intensity regions. One or more outlet channels may be located between two high-intensity regions. The shown design provides optimal cooling for this particular heat map, which is a grayscale map in the form of three rectangles.

[0180] For Figure 4A The cold plate for the shown embodiment can be seen in Figure 5A . The cold plate has an outer surface for facing the computing device. The cold plate has an inner surface adapted to contact the cooling liquid. The cold plate assembly also has a distribution layer. The cold plate has mounting holes 501 for fastening means such that the top layer of the system can be held on the cold plate together with the distribution layer and such that the system becomes liquid-tight. In other embodiments, the cold plate assembly can be held together by other fastening means (such as clamps or glue). The inlet channels are partially formed by the features 405 and 407 in combination with the distribution layer. Although the grooves in the cold plate extend all the way around the microchannels 401, Figure 4A the inlet channel 407 of the cooling system embodiment is blocked by a part of the distribution layer such that the inlet channel is restricted to a part of the microchannel, as shown in Figure 4A . As the cross-sectional area of the inlet channel in the distribution layer decreases in the region above the constriction 409, the size of the intermediate inlet channel 405 decreases at the constriction 409.

[0181] In Figure 5B can be seen the magnification of the middle of the cold plate shown in Figure 5A . The intermediate inlet channel 405 is visible and the microchannels 401 can be seen. The shape of the constriction 409 in the inlet channel 405 is regarded as the region of the microchannel extending through the region of the inlet channel. However, the inlet channel of this embodiment is not blocked as it extends in the distribution layer above the cold plate. The inlet channel expands again after the constriction 409. The constriction 409 causes an increase in the flow resistance of the liquid at the location of the constriction 409. This reduces the pressure in the channel after the constriction 409. As the size of the inlet channel increases again, the pressure does not decrease significantly immediately after the constriction and until the liquid enters the microchannel. Generally, the flow resistance is highest when the size of the channel is smallest. Therefore, the pressure decreases as the size of the channel decreases. As the channel becomes longer, the pressure also decreases. It can be seen that the greatest flow resistance and pressure loss are due to the microchannels in the cold plate assembly.

[0182] In order to be able to cool certain places on the cold plate more than others, it is important to be able to control the flow rate of the liquid and be able to distinguish between them. In addition, it is important that the liquid can exchange heat with the cold plate. The heat exchange between the cold plate and the liquid depends on the contact surface area between them. The choice of the cooling liquid and the material of the cold plate are also relevant factors for controlling the heat exchange. Another important parameter is the liquid pressure at the inlet and outlet. The pressure can be controlled by a pump, so the maximum pressure in the cooling system is limited by the choice of the pump.

[0183] In Figure 5C the cold plate is viewed from below, that is, the outer surface of the cold plate is shown. This surface is the surface to be arranged in contact with the computing device for cooling. The cold plate has holes 501 for fastening different parts of the assembly to hold them together.

[0184] The distribution layer placed on top of the cold plate can be seen in Figure 6A . The inlet 405 is shown, and the outlet 407 can also be seen. The top layer of the assembly is not shown in Figure 6A , but in the installed cooling assembly it will be used to hold the distribution layer by fastening means, which can be fastened through the mounting holes 501.

[0185] The distribution layer forms part of the inlet channel 405 and the outlet channel 409. This can be seen in Figure 6B , where the distribution layer is seen from below, that is, the side in contact with the cold plate when the cold plate assembly is assembled, so that the channels for distributing the cooling liquid can be seen. The distribution layer can be made of a deformable material such as rubber. The deformable material helps to make the cold plate assembly liquid-tight, so the distribution layer 107 also serves as a sealing layer.

[0186] A cross-section of an embodiment of the cold plate assembly is shown in Figure 7 . Some channels can be seen here, such as the inlet channel 405 partly formed in the distribution layer 107 and the cold plate 105. The top layer, the distribution layer 107 and the cold plate are held together by fastening means such as using the mounting holes 501.

[0187] Since an important aspect of the present invention is to transfer heat from the cold plate to the liquid flowing through the cold plate assembly, the arrangement of the microchannels is of great significance for effective cooling. The microchannels can be made in different ways and have different shapes. One way to produce microchannels is to manufacture fins by mechanical splitting, thus forming microchannels between the fins. Figure 5A The embodiment of

[0188] Another way to fabricate microchannels is to 3D print them. Since 3D printing is a very versatile method, microchannels of almost any shape can be produced. By 3D printing a cold plate, microchannels can be fabricated in multiple layers stacked on top of each other. The channels can also be made to have bends. The channels produced by 3D printing can start in the top layer and can be redirected to a new layer closer to the outer surface of the cold plate when needed. This can help improve the heat exchange between the liquid and the cold plate without losing too much pressure.

[0189] In Figure 8 、 Figure 9 and Figure 10 possible arrangements of the microstructure of embodiments of cold plates with 3D printed microchannels are shown.

[0190] In Figure 8 a cross - section along the liquid flow direction of a 3D printed microchannel is shown. The microchannel has walls 805 to define the microchannel. The flow of the liquid is shown by arrow 801. The microchannel has fin - shaped protrusions 803 extending into the microchannel. The fins can start from the bottom of the microchannel and end at the top, or they can only extend a part of the path. The protruding microstructures can be shaped in other ways, such as Figure 9 the cylinders or irregular shapes shown. Different shapes can be fabricated to optimize heat transfer.

[0191] Figure 9 The microchannel shown in

[0192] In Figure 8 and Figure 9 only one microchannel is shown, but this may be the form of all or some of the microchannels in a cold plate assembly. Similarly, different types of microstructures can be found on the various microchannels of the same cold plate assembly. Using 3D printing, the microchannels can also be fabricated such that they are completely contained within the cold plate. This can help keep the system liquid - tight.

[0193] In Figure 10 another embodiment of a channel of the present invention with 3D printed microstructures is shown. The flow path is along arrow 951. The 3D structure shown can be made by placing material beams in a 3D lattice. The side where the liquid enters the channel as shown by arrow 951 is called the first end. The Figure 10 other two sides visible in Figure 10(not visible in the figure). The white rectangle 953 shows a channel that extends straight through the microchannel. Since these channels extend through the microchannel from all three sides, the microchannel is divided into 9 channels at the first end, but all these channels are connected to each other within the microchannel. To guide the liquid through the microchannel, the top 955, the bottom, the first side 957, and the second side can be covered with solid material so that no liquid can flow into or out of these four surfaces. This is a diagram of a microchannel, and some or all of the microchannels in the cold plate assembly can be shaped like this.

[0194] The following is a list of reference numerals used in the detailed description of the present disclosure and in the drawings referred to in the detailed description of the present disclosure.

[0195] 101 Inlet for cooling liquid

[0196] 103 Outlet for cooling liquid

[0197] 105 Cold plate with guiding device

[0198] 109 Top layer

[0199] 200 Computing device

[0200] 201 Core Composite Die (CCD)

[0201] 203 I / O Die (IOD)

[0202] 301 Thermal map of IOD

[0203] 303 Figure 2 Position of the hottest part of the chip design in

[0204] 401 Microchannel

[0205] 403 Inlet channel

[0206] 404 Constriction section of the inlet channel

[0207] 405 Inlet

[0208] 407 Outlet for cooling liquid

[0209] 409 Outlet channel

[0210] 409’ Endpoint of the outlet channel

[0211] 501 Hole for fastening the parts together

[0212] 600 Method for obtaining a cold plate assembly

[0213] 602 Obtaining a thermal map

[0214] 604 Obtaining a flow type

[0215] Obtain the positions of at least one flow splitting and one flow confluence of the cold plate assembly

[0216] Obtain the positions of all flow types in the cold plate assembly

[0217] Obtain the number, dimensions, shape, and positions of the inlets and outlets of the distribution layer

[0218] Obtain the dimensions, positions, shape, and number of the channels in the cold plate

[0219] Divide the heat map into smaller regions and classify these regions as high-intensity or low-intensity regions

[0220] Classify all intensity regions such that each region belongs to one of the following categories: high-priority region or low-priority region

[0221] Define the positions of the inlets and outlets of the cold plate assembly

[0222] Perform iterative optimization of the flow type, inlet channels, microchannels, and the positions, numbers, and dimensions of the outlet channels

[0223] Arrow indicating the liquid flow

[0224] Protruding microstructures in the microchannels

[0225] Walls of the microchannels

[0226] Microstructure protrusions formed as cylinders

[0227] Arrow indicating the liquid flow direction

[0228] Channels extending through the microchannel structure

[0229] Top side of the microchannel

[0230] First side of the microchannel

[0231] The following is a set of items that constitute aspects of the present disclosure. These aspects of the present disclosure can be considered separately patentable, and thus the following multiple sets form the basis for possible multiple sets of future claims:

[0232] 1. A cold plate assembly for use in a liquid cooling system for cooling a computing device having a plurality of working areas, wherein heat diffuses from the plurality of working areas with a varying intensity from one or more high-intensity areas to one or more low-intensity areas, the cold plate assembly comprising:

[0233] A cold plate for exchanging heat between the computing device and the cooling liquid of the liquid cooling system, the cold plate comprising an outer surface for facing the computing device and an opposite inner surface adapted to contact the cooling liquid, the inner surface further comprising guiding means for guiding the cooling liquid along the inner surface in a predetermined pattern, the predetermined pattern causing the liquid flow to concentrate through one or more predetermined high-priority regions

[0234] A distribution layer configured to be mounted on the inner surface of the cold plate, the distribution layer comprising:

[0235] - A liquid inlet through which the inner surface of the cold plate receives cooling liquid from the liquid cooling system, and

[0236] - A liquid outlet through which the cooling liquid is discharged from the inner surface into the liquid cooling system,

[0237] The liquid inlet is in liquid communication with an inlet channel, and the inlet channel and the liquid outlet are in liquid communication with an outlet channel,

[0238] such that the liquid flow is guided from the inlet channel through the cold plate to the outlet channel by the guiding means, the inlet channel being arranged such that when the cold plate assembly is arranged to cool the computing device, the inlet channel at least partially coincides with the high-intensity region of the computing device.

[0239] 2. The cold plate assembly according to item 1, wherein when the cold plate assembly is arranged to cool the computing device, at least one of the one or more predetermined high-priority regions coincides with one of the one or more high-intensity regions of the computing device.

[0240] 3. The cold plate assembly according to any one of the preceding items, comprising a plurality of inlet channels connected into an inlet network and / or a plurality of outlet channels connected into an outlet network.

[0241] 4. The cold plate assembly according to item 3, wherein the inlet network and the outlet network are connected via microchannels.

[0242] 5. The cold plate assembly according to any one of the preceding items, wherein the inlet channels and the outlet channels are arranged on opposite sides of the relatively hottest part of the working area.

[0243] 6. The cold plate assembly according to any one of the preceding items, wherein at least one inlet channel comprises a constriction such that by gradually reducing and / or stepwise reducing the cross-sectional area of the inlet channel, the cross-sectional area is larger at a first position than at a second position.

[0244] 7. The cold plate assembly according to any one of the foregoing items, which includes a plurality of microchannels and / or inlet channels and / or outlet channels, and the plurality of microchannels and / or inlet channels and / or outlet channels are arranged in multiple layers in a stacked manner relative to the outer surface of the cold plate.

[0245] 8. The cold plate assembly according to any one of the foregoing items, which includes one or more microstructures that project at least partially transversely to the liquid flow direction in one or more of the microchannels.

[0246] 9. The cold plate assembly according to any one of the foregoing items, wherein the cold plate is constructed by 3D printing.

[0247] 10. A method for designing a cold plate assembly, which includes the following steps:

[0248] Obtain a surface temperature distribution map of the target computing device,

[0249] Define a fixed inlet position and a fixed outlet position of the cold plate assembly,

[0250] Iteratively optimize the placement and / or quantity and / or size of the inlet channel, outlet channel, and / or microchannels of the cold plate assembly to minimize the temperature simulated based on the surface temperature distribution map of the combined system of the cold plate assembly and the computing device.

[0251] 11. According to the method of item 10, the temperature to be minimized during optimization is the overall temperature maximum or the average temperature, such as the total average or average temperature of the region corresponding to the highest 10% temperature range of the temperature distribution map.

[0252] 12. According to the method of any one of items 10 and 11, it further includes the following steps:

[0253] Based on the surface temperature distribution map, define a plurality of priority regions according to the predetermined temperature limits of each priority region,

[0254] Before optimizing the cold plate assembly, divide the plurality of priority regions into at least two categories according to the highest surface temperature of each region, and one of the at least two categories is a high-priority region, so that at least one high-priority region is assigned, and

[0255] Define the high-priority region as the temperature minimization region.

[0256] 13. According to the method of item 12, one of the at least two categories is a low-priority region, so that at least one low-priority region is assigned, and the optimization is restricted to keeping the highest temperature of the low-priority region below a predetermined threshold.

[0257] 14. A method according to any one of items 12 and 13, which includes more than two categories, the categories being hierarchically ordered, the highest category in the hierarchy being the high-priority area, and each other category being assigned a different predetermined threshold, such that the predetermined threshold of the temperature is the highest for the area lowest in the hierarchy.

[0258] 15. A method according to any one of items 10 to 14, which further predetermines a fixed position of one or more inlet channels.

[0259] 16. A cold plate assembly for use in a liquid cooling system for cooling a computing device having a plurality of working areas from which heat is dissipated with varying intensity, the cold plate assembly comprising:

[0260] A cold plate for exchanging heat between the computing device and the cooling liquid of the liquid cooling system, the cold plate including an outer surface for facing the computing device and an opposite inner surface adapted to contact the cooling liquid, the inner surface further including guiding means for guiding the cooling liquid along the inner surface in a predetermined pattern that causes the liquid flow to concentrate through one or more areas;

[0261] A distribution layer configured to be mounted on the inner surface of the cold plate, the distribution layer including:

[0262] - A liquid inlet through which the inner surface of the cold plate receives cooling liquid from the liquid cooling system, and

[0263] - A liquid outlet through which the cooling liquid is discharged from the inner surface into the liquid cooling system,

[0264] The liquid inlet is in liquid communication with an inlet channel, and the inlet channel and the liquid outlet are in liquid communication with an outlet channel,

[0265] such that at least a first area of the cold plate assembly is adapted for liquid flow of one of the types of split flow, confluent flow, or direct flow, a second area of the cold plate is adapted for one of the types of split flow, confluent flow, or direct flow type, and the second flow type is different from the first flow type.

[0266] 17. The cold plate assembly according to item 16, wherein the first area of the cold plate assembly has a split type of liquid flow and the second area has a confluent type of liquid flow.

[0267] 18. The cold plate assembly according to any one of the preceding items, wherein the first area overlaps with a first working area of the computing device and the second area overlaps with a second working area of the computing device.

[0268] 19. The cold plate assembly according to any one of the preceding items, wherein the first working area and the second working area are separated from each other.

[0269] 20. The cold plate assembly according to any one of the preceding items, wherein the first area and the second area do not overlap, such that the confluent outlet channel receives liquid from the shunt.

[0270] 21. The cold plate assembly according to any one of the preceding items, which includes a plurality of inlet channels connected into an inlet network and / or a plurality of outlet channels connected into an outlet network.

[0271] 22. The cold plate assembly according to item 21, wherein the inlet network and the outlet network are connected via microchannels.

[0272] 23. The cold plate assembly according to any one of the preceding items, wherein the inlet channels and the outlet channels are arranged on opposite sides of the local temperature maximum of the working area.

[0273] 24. The cold plate assembly according to any one of the preceding items, wherein at least one inlet channel includes a constriction such that by gradually reducing and / or stepwise reducing the cross-sectional area of the inlet channel, the cross-sectional area is larger at a first position than at a second position.

[0274] 25. A method of designing a cold plate assembly, which includes the following steps: obtaining a surface temperature distribution map of a target computing device, defining fixed inlet positions and fixed outlet positions of the cold plate assembly, and iteratively optimizing the placement and / or quantity and / or dimensions of the inlet channels, outlet channels, and / or microchannels of the cold plate assembly to minimize the temperature simulated based on the surface temperature distribution map of the combined system of the cold plate assembly and the computing device.

[0275] 26. The method according to item 25, wherein the temperature to be minimized during optimization is the overall temperature maximum or the average temperature, such as the total average or average temperature of the area corresponding to the highest 10% temperature range of the temperature distribution map.

[0276] 27. The method according to item 25 or 26, which further includes the following steps:

[0277] Based on the surface temperature distribution map, defining a plurality of priority areas according to the predetermined temperature limits of each priority area, dividing the plurality of priority areas into at least two categories according to the highest surface temperature of each area, one of the at least two categories being the high-priority area, such that at least one high-priority area is allocated, and

[0278] Define the high-priority region as a temperature minimization region for subsequent optimization of the cold plate assembly.

[0279] 28. The method according to item 27, wherein one of the at least two categories is a low-priority region, such that at least one low-priority region is allocated, and wherein the optimization is limited to keeping the highest temperature of the low-priority region below a predetermined threshold.

[0280] 29. The method according to item 27 or 28, which includes more than two categories, the categories being hierarchically ranked, wherein the highest category in the hierarchy is the high-priority region, and each other category is assigned a different predetermined threshold, such that the predetermined threshold for the temperature is the highest for the region lowest in the hierarchy.

[0281] 30. The method according to any one of items 25 to 29, which also predetermines fixed positions of one or more inlet channels.

Claims

1. A cold plate assembly for use in a liquid cooling system for cooling a computing device having a plurality of working areas from which heat dissipates with varying intensity, the cold plate assembly comprising: A cold plate for exchanging heat between the computing device and a cooling liquid of the liquid cooling system, the cold plate including an outer surface for facing the computing device and an opposite inner surface adapted to contact the cooling liquid, the inner surface further including guiding means for guiding the cooling liquid along the inner surface in a predetermined pattern that causes the liquid flow to concentrate through one or more areas; A distribution layer configured to be mounted on the inner surface of the cold plate, the distribution layer including: - A liquid inlet through which the inner surface of the cold plate receives the cooling liquid from the liquid cooling system, and - A liquid outlet through which the cooling liquid is discharged from the inner surface into the liquid cooling system, The liquid inlet is in liquid communication with an inlet channel, and the inlet channel and the liquid outlet are in liquid communication with an outlet channel, such that at least a first area of the cold plate assembly is adapted to have a liquid flow of one of the types of split flow, combined flow, or direct flow, a second area of the cold plate is adapted to have a liquid flow of one of the types of split flow, combined flow, or direct flow, and the second flow type is different from the first flow type.

2. The cold plate assembly according to claim 1, wherein the first area of the cold plate assembly has a split flow type of liquid flow and the second area has a combined flow type of liquid flow.

3. The cold plate assembly according to any one of the preceding claims, wherein the first area overlaps a first working area of the computing device and the second area overlaps a second working area of the computing device.

4. The cold plate assembly according to any one of the preceding claims, wherein the first working area and the second working area are separated from each other.

5. The cold plate assembly according to any one of the preceding claims, wherein the first area and the second area do not overlap such that the combined outlet channel receives liquid from the split flow.

6. The cold plate assembly according to any one of the preceding claims, comprising a plurality of inlet channels connected into an inlet network and / or a plurality of outlet channels connected into an outlet network.

7. The cold plate assembly according to claim 6, wherein the inlet network and the outlet network are connected via microchannels.

8. The cold plate assembly according to any one of the preceding claims, wherein the inlet channels and the outlet channels are arranged on opposite sides of the location of the highest local temperature of the working area.

9. The cold plate assembly according to any one of the preceding claims, wherein at least one inlet channel includes a constriction such that the cross-sectional area of the inlet channel is gradually reduced and / or stepped down, the cross-sectional area being larger at a first location than at a second location.

10. A method of designing a cold plate assembly, which comprises the following steps: Obtain the surface temperature distribution map of the target computing device, define the fixed inlet position and fixed outlet position of the cold plate assembly, and iteratively optimize the placement and / or quantity and / or size of the inlet channel, outlet channel, and / or microchannel of the cold plate assembly so as to minimize the temperature simulated based on the surface temperature distribution map of the combined system of the cold plate assembly and the computing device.

11. The method according to claim 10, wherein the temperature to be minimized during optimization is the overall temperature maximum or the average temperature, such as the total average or average temperature of the region corresponding to the highest 10% temperature range of the temperature distribution map.

12. The method according to claim 10 or 11, further comprising the steps of: Based on the surface temperature distribution map, define a plurality of priority regions according to the predetermined temperature limits of each priority region, divide the plurality of priority regions into at least two categories according to the highest surface temperature of each region, one of the at least two categories being the high-priority region, such that at least one high-priority region is assigned, and Define the high-priority region as the temperature minimization region for subsequent optimization of the cold plate assembly.

13. The method according to claim 12, wherein one of the at least two categories is the low-priority region, such that at least one low-priority region is assigned, and wherein the optimization is restricted to keeping the highest temperature of the low-priority region below a predetermined threshold.

14. The method according to claim 12 or 13, which includes more than two categories, the categories being hierarchically sorted, wherein the highest category in the hierarchical structure is the high-priority region, and each other category is assigned a different predetermined threshold, so that the predetermined threshold of the temperature is the highest for the region lowest in the hierarchical structure.

15. The method according to any one of claims 10 to 14, further predetermining the fixed positions of one or more inlet channels.

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