TECHNICAL FIELD

[0001] The present disclosure generally relates to cooling systems, and more specifically to a system and a method for single-phase immersion cooling.

BACKGROUND

[0002] Data centers, supercomputers, and generally large electronic systems are comprised of a high number of electronic circuit boards. Each electronic circuit board holds a number of electronic components, which heat up during their operation. Electronic components, such as integrated circuits (ICs), are more susceptible to malfunction or damage when they overheat.

[0003] Two main broad methods of cooling electronic systems are known in the art: "air cooling" and "liquid cooling". Air-cooling involves circulating air between the electronic components for preventing the components from overheating. However, as the density of components on electronic circuits have increased, and the clock speeds at which they operate have gone up, air cooling may not be an adequate method for cooling many electronic systems. Liquid cooling has shown to be more effective than air-cooling since liquids used in liquid cooling systems have superior heat transfer capacities compared to air. An example of liquid cooling is "immersion cooling".

[0004] Immersion cooling typically involves immersing electronic components of electronic circuits making up an electronic system in a bath of "heat-dissipating medium", for dissipating heat generated by said electronic components during their operation. A nonlimiting example of a "heat-dissipating medium" is a dielectric fluid. Dielectric fluids are preferred in immersion cooling systems because they do not conduct electricity and hence minimize the likelihood that electronic components bathed in the dielectric fluid will be damaged by "short circuiting", for example.

[0005] Single-phase and two-phase immersion systems exist. In a single-phase liquid immersion cooling system, when the heat-dissipating medium comes into contact with electronic components, heat is dissipated to the heat-dissipating medium thus "cooling" the components. A two-phase liquid immersion cooling system uses a low-temperature evaporation process to dissipate heat from hot electronic components. The heat-dissipating medium used has a low evaporation temperature and becomes vaporized when it comes into contact with the hot electronic components. In doing so, the electronic components lose heat equivalent to the latent heat that causes the heat-dissipating medium to vaporize, thereby maintaining the electronic components within desired operational temperatures. The vaporized heat-dissipating medium is cooled and condensed, then returned to the liquid circulation.

[0006] A number of problems are encountered in single-phase immersion cooling systems in which the electronic circuits are housed in a holding tank through which a dielectric fluid is pumped. These problems include insufficient or uneven cooling of the electronic components thus causing system malfunction or even permanent electronic component damage.

SUMMARY

[0007] According to a part of the present disclosure, there is provided an immersion cooling system comprising a tank, a first box header, and a first chassis cluster. The tank has a tank bottom and a tank sidewall extending from the tank bottom and forming a tank interior space therewith for receiving a bathing heat-dissipating medium. The tank has a tank outlet in the tank sidewall for dispensing a warmed heat-dissipating medium therethrough. The first box header is disposed in the tank interior space. The first box header has a first box header interior space, a first box header inlet for receiving a cooled heat-dissipating medium into the first box header interior space therethrough, and a top wall. The top wall includes a first plurality of spaced-apart box-header orifices of equal cross sectional areas for dispensing the cooled heat-dissipating medium therethrough. The first chassis cluster comprises a first plurality of chassis, disposed on the first box header. Each one of the first plurality of chassis comprises a chassis top end, a chassis bottom end, and a chassis sidewall extending between the chassis top end and the chassis bottom end. The chassis sidewall forms a chassis interior space adapted for receiving a first plurality of electronic circuit boards in an upright orientation. The first plurality of spaced-apart box header orifices are arranged to each inject the cooled heat-dissipating medium into the chassis bottom end of a respective one of the first plurality of chassis. The first box header is configured to cause a buildup of pressure of the cooled heat-dissipating medium in the first box header interior space such that the cooled heat-dissipating medium is dispensed into the chassis bottom end of each one of the first plurality of chassis with the same flow rate. [0008] In an embodiment, the immersion cooling system further comprises a pump in fluid communication with the tank outlet, a cooling means in fluid communication with the pump and a feeder means in fluid communication with the cooling means and the box header inlet. The warmed heat-dissipating medium dispensed from the tank outlet is drawn by the pump and driven by the pump through the cooling means to be cooled and exits the cooling means as the cooled heat-dissipating medium. The cooled heat-dissipating medium is passed through the feeder means into the first box header inlet, and is dispensed through the first plurality of box header orifices into the first plurality of chassis.

[0009] In an embodiment, the first plurality of box header orifices are sized to dispense the cooled heat-dissipating medium into the bottom end of each one of the first plurality of chassis with a velocity which creates a low pressure region in a center of the chassis interior space of each one of the first plurality of chassis.

[0010] In an embodiment, the low-pressure region causes the bathing heat-dissipating medium present in the chassis interior space of each one of the first plurality of chassis to be drawn towards the center of the chassis interior space and mix with the cooled heatdissipating.

[0011] In an embodiment, the top wall of the first box header is arranged to close the chassis bottom end of each one of the first plurality of chassis for preventing the heatdissipating medium from leaking out from that chassis bottom end.

[0012] In an embodiment, the outlet of the tank is located at a level in the sidewall, which is above the chassis top end of each one of the first plurality of chassis.

[0013] In an embodiment, the immersion cooling system wherein each one of the first plurality of chassis further comprises a retaining means for retaining at least some of the plurality of electronic circuit boards in the chassis interior space of at least some of the first plurality of chassis in the upright orientation.

[0014] In an embodiment, the immersion cooling system further comprises a second box header and a second chassis cluster. The second box header is disposed in the tank interior space above the first chassis cluster and is vertically spaced therefrom. The second box header has a second box header interior space, a second box header inlet for receiving a cooled heat-dissipating medium into the second box header interior space therethrough, and a top wall. The top wall of the second box header includes a second plurality of spaced-apart box header orifices of equal cross sectional areas for dispensing the cooled heat-dissipating medium therethrough. The second chassis cluster comprises a second plurality of chassis, disposed on the second box header. Each one of the second plurality of chassis comprises a chassis top end, a chassis bottom end, and a chassis sidewall extending between the chassis top end and the chassis bottom end. The chassis sidewall forms a chassis interior space adapted for receiving a second plurality of electronic circuit boards in the upright orientation. The second plurality of spaced-apart orifices are arranged to each dispense the cooled heatdissipating medium into the chassis bottom end of a respective one of the second plurality of chassis. The second box header is configured to cause a buildup of pressure of the cooled heat-dissipating medium in the second box header interior space such that the heatdissipating medium is injected into the chassis bottom end of each one of the second plurality of chassis with the same flow rate.

[0015] In an embodiment, the immersion cooling system further comprises a spacer disposed above the first chassis cluster and below the second box header for vertically spacing the second box header from the first chassis cluster.

[0016] In an embodiment, the spacer comprises a plurality of parallel fins spaced to be aligned with the chassis sidewalls of the first chassis cluster.

[0017] In another embodiment, the second box header is vertically spaced from the first chassis cluster by being suspended via a bracket or fabricated shelving means

[0018] In an embodiment, the immersion cooling system further comprises a pump in fluid communication with the tank outlet, a cooling means in fluid communication with the pump, a pipe header, and a first and a second feeder means. The pipe header has an inlet in fluid communication with the cooling means, and a pipe header body. The pipe header body includes a first pipe header orifice having a first cross sectional area and a second pipe header orifice having a second cross sectional area equal to the first cross sectional area. The pipe header body is configured to cause a buildup of pressure therein such that the cooled heatdissipating medium is dispensed from the first and second pipe header orifices with the same flow rate. The first feeder means is in fluid communication with the first pipe header orifice and the first box header inlet. The second feeder means is in fluid communication with the second pipe header orifice and the second box header inlet. The warmed heat-dissipating medium dispensed from the tank outlet is drawn by the pump and driven by the pump through the cooling means to be cooled and exits the cooling means as the cooled heat-dissipating medium. The cooled heat-dissipating medium is drawn by the pump and driven by the pump passed through cooling means to be cooled and exits the cooling means as the cooled heatdissipating medium. The cooled heat-dissipating medium is passed through the pipe header inlet into the pipe header body. The cooled heat-dissipating medium is then dispensed from the pipe header through the first and second pipe header orifices and passed through the first and second feeder means into the first and second box headers, respectively. The cooled heat-dissipating medium is then dispensed through the first and second plurality of box header orifices into the first and second plurality of chassis, respectively.

[0019] In an embodiment, the first and second plurality of box header orifices are sized to dispense the cooled heat-dissipating medium into the bottom end of each one of the first and second plurality of chassis with a velocity which creates a low pressure region in a center of the chassis interior space of each one of the first and second plurality of chassis.

[0020] In an embodiment, the low-pressure region causes the bathing heat-dissipating medium present in the chassis interior space of each one of the first and second plurality of chassis to be drawn towards the center and mix with the cooled dispensed heat-dissipating medium.

[0021] In an embodiment, the top wall of the first box header is arranged to close the chassis bottom end of each one of the first plurality of chassis, and the top wall of the second box header is arranged to close the chassis bottom end of each one of the second plurality of chassis.

[0022] In an embodiment, the outlet of the tank is at a level in the sidewall that is above the chassis top end of each one of the second plurality of chassis.

[0023] In an embodiment, each one of the first and second plurality of chassis further comprises a retaining means for retaining at least some of the first and second plurality of electronic circuit boards in the chassis interior space of at least some of the first and second plurality of chassis in the upright orientation.

[0024] According to another part of the present disclosure, there is provided a method of immersion cooling of a plurality of electronic boards housed in a plurality of chassis having similar dimensions and disposed in a tank. The method comprises dispensing a cooled heat- dissipating medium with the same flow rate into a bottom end of each of the plurality of chassis such that the cooled heat-dissipating medium cools the plurality of electronic boards and exits each of the plurality of chassis at a top end thereof as a warmed heat-dissipating medium. The method further comprises drawing the warmed heat-dissipating medium out of the tank, cooling the heat-dissipating medium to produce a cooled heat-dissipating medium, and passing the cooled heat-dissipating medium back to be dispensed into the bottom end of each one of the plurality of chassis.

[0025] In an embodiment, passing the cooled heat-dissipating medium back to be dispensed into the bottom end of each of the plurality of chassis comprises dispensing the cooled heat-dissipating medium from a plurality of orifices each arranged to dispense the cooled heat-dissipating medium into one of the plurality of chassis.

[0026] According to another part of the disclosure, there is provided a method of immersion cooling of a first plurality of electronic boards housed in a first plurality of chassis having similar dimensions, and a second plurality of electronic boards housed in a second plurality of chassis having similar dimensions, the first and second plurality of chassis being disposed in a tank. The method comprises dispensing a cooled heat-dissipating medium with the same flow rate into a bottom end of each of the first and second plurality of chassis such that the cooled heat-dissipating medium cools the first and second plurality of electronic boards and exits each of the first and second plurality of chassis at a top end thereof as a warmed heat-dissipating medium. The method further comprises drawing the warmed heatdissipating medium out of the tank, cooling the warmed heat-dissipating medium to produce a cooled heat-dissipating medium, passing the cooled heat-dissipating medium to a pipe header, and passing the cooled heat-dissipating medium from the pipe header to each of a first box header disposed under the first plurality of chassis and a second box header disposed under the second plurality of chassis.

[0027] In an embodiment, the second plurality of chassis is disposed above the first plurality of chassis in the tank.

[0028] This summary does not necessarily describe the entire scope of all aspects of the disclosure. Other aspects, features and advantages will be apparent to those of ordinary skill in the art upon review of the following description of specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In the accompanying drawings, which illustrate one or more embodiments:

[0030] FIG. 1A is a top plan view of a single chassis shown with three electronic circuit boards housed therein;

[0031] FIG. IB is front elevational view of the single chassis of FIG. 1A;

[0032] FIG. 1C is side elevational view of the single chassis of FIG. 1A showing the electronic connections of the electronic circuit boards;

[0033] FIG. ID is a perspective view of the single chassis of FIG. 1A;

[0034] FIG. 2 is a top-front perspective view of a chassis cluster comprised of six chassis each similar to the single chassis of FIGS. 1A-1C, with each chassis shown housing three electronic boards therein;

[0035] FIG. 3A is a top perspective view of a box header having a side inlet and six top orifices;

[0036] FIG. 3B is a top plan view of the box header of FIG. 3A;

[0037] FIG. 3C is a front elevational view of the box header of FIG. 3A;

[0038] FIG. 4A is a top view of a spacer including five fins;

[0039] FIG. 4B is a front elevational view of the spacer of FIG. 4A;

[0040] FIG. 4C is a side elevational view of the spacer of FIG. 4A;

[0041] FIG. 5 is a top-front perspective view of the spacer of FIGS. 4A-4C stacked on top of the chassis cluster of FIG. 2;

[0042] FIG. 6A is a perspective view of a tank used to hold a heat-dissipating medium, at least one chassis and at least one box header therein;

[0043] FIG. 6B is a top plan view of the tank of FIG. 6A shown with four clusters of chassis, each cluster comprising six chassis, and each chassis holding three electronic boards; [0044] FIG. 7 is a system diagram for an immersion cooling systems featuring a single chassis cluster and a single box header, in accordance with an embodiment of the present disclosure;

[0045] FIG. 8 is a system diagram for an immersion cooling systems featuring three chassis clusters and two box headers in a stacked arrangement, in accordance with an embodiment of the present disclosure;

[0046] FIG. 9 is a flow chart of a method of immersion cooling of a plurality of electronic boards housed in a chassis cluster disposed in a tank, in accordance with an embodiment of the present disclosure; and

[0047] FIG. 10 is a flow chart of a method of immersion cooling of a first plurality of electronic boards housed in a first chassis cluster, and a second plurality of electronic boards housed in a second chassis cluster, in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION

[0048] Directional terms such as "top," "bottom," "upwards," "downwards," "left," "right," "vertically," and "laterally" are used in the following description for the purpose of providing relative reference only, and are not intended to suggest any limitations on how any article is to be positioned during use, or to be mounted in an assembly or relative to an environment. The use of the word "a" or "an" when used herein in conjunction with the term "comprising" may mean "one," but it is also consistent with the meaning of "one or more," "at least one" and "one or more than one." Any element expressed in the singular form also encompasses its plural form. Any element expressed in the plural form also encompasses its singular form. The term "plurality" as used herein means more than one; for example, the term "plurality includes two or more, three or more, four or more, or the like.

[0049] In this disclosure, the terms "comprising", "having", "including", and "containing", and grammatical variations thereof, are inclusive or open-ended and do not exclude additional, un-recited elements and/or method steps. The term "consisting essentially of" when used herein in connection with a composition, use or method, denotes that additional elements, method steps or both additional elements and method steps may be present, but that these additions do not materially affect the manner in which the recited composition, method, or use functions. The term "consisting of" when used herein in connection with a composition, use, or method, excludes the presence of additional elements and/or method steps.

[0050] In this disclosure, the term "chassis" refers to a single compartment structure used to hold electronic circuit boards. When a plurality of chassis are coupled, they form a "chassis cluster", "cluster of chassis", or simply a "cluster".

[0051] In this disclosure, the term "heat-dissipating medium" represents a fluid, such as a liquid or a gas, which dissipates heat from an object when such fluid comes into contact therewith. A person skilled in the art would understand that such a fluid when used in immersion cooling would need to be non-electrically conductive. A non-limiting example of such fluid is a "dielectric cooling liquid". When a heat-dissipating medium is cooled by any cooling means it is referred to as a "cooled heat-dissipating medium". When a heatdissipating medium comes into contact with hot objects, its temperature rises, and it is then referred to as a "warmed heat-dissipating medium". A heat-dissipating medium received in a tank and used to bath the contents of the tank is referred to as a "bathing heat-dissipating medium".

[0052] In this disclosure, the terms "electronic board" and "electronic circuit board" refer to an electronic printed circuit board (PCB) which carries a number of electronic components such as integrated circuits (ICs) and/or discrete components such as resistors, inductors, and capacitors. The electronic circuit board may carry dual in-line package (DIP) components, surface mount technology (SMT) components, or discrete components. The electronic board may also have a number of heat sinks attached to some of the components for dissipating some of the heat therefrom.

[0053] In this disclosure, the term "feeder means" represents a structure through which a fluid may be conveyed from one point to another. One example of such feeder means is a pipe. Another example is a hose.

[0054] In this disclosure, the term "inlet" or "inlet means" represents a structure through which a fluid is fed into the interior space of another structure. An inlet may be a straight pipe, a curved pipe, a hose, a conduit, or any other equivalent structure known in the art. [0055] In this disclosure, the term "cooling means" refers to one or more than one device that dissipates heat from a fluid when said fluid passed therethrough. A non-limiting example of a cooling means is a heat exchanger.

[0056] In this disclosure, the passing of a fluid through one or more "cooling means" is referred to as "cooling" that fluid. In this disclosure, "cooling" refers to the dissipation of heat. Additionally, the fluid leaving the "cooling means" is referred to as the "cooled" fluid.

[0057] In this disclosure, the term "retaining means" refers to a mechanical structure that maintains an electronic circuit board in position inside a chassis. Examples of the retaining means include grooves and slots, which receive and maintain electronic circuit boards in the chassis. Other structures such as clips or fasteners are other examples of "retaining means". In some embodiments, the retaining means may comprise an adhesive.

[0058] In this disclosure, the term "orifice" refers to an opening, a hole, or an aperture used for dispensing a fluid.

[0059] In this disclosure, the term "pump" refers to one or more apparatus or machine for raising, driving, exhausting, or compressing fluids or gases by means of a piston, plunger, or set of rotating vanes. One example of the pump is a chiller pump that circulates a cooled fluid in a closed system.

[0060] In this disclosure, the term "spacer" refers to a mechanical structure that provides a spacing between two other objects such that they do not touch or abut one another.

[0061] Embodiments of the present disclosure are presented below by way of example only and not limitation.

[0062] FIGS. 1A-1C (collectively "FIG. 1") show a chassis 100, in accordance with an embodiment of a single-phase immersion cooling system. The chassis 100 comprises a top end 125, a bottom end 127, and a sidewall 102 extending between the top end 125 and the bottom end 127. The chassis sidewall 102 forms a chassis interior space adapted for receiving a plurality of electronic circuit boards in an upright orientation. In the embodiment depicted in FIG. 1, the chassis 100 is in the shape of a cuboid formed by a sidewall 102 including: right wall 110, front wall 112, left wall 114, and rear wall 116. In other embodiments, the shape of the chassis 100 can be any suitable shape known in the art. The chassis 100 is open at the top end 125 and open at the bottom end 127. The sidewall 102 of the chassis 100 has retaining means for receiving and maintaining at least one electronic circuit board in a vertical orientation in the chassis. In an embodiment, the front wall 112 includes the vertical grooves 120, which are configured to receive one end of an electronic circuit board. The rear wall 116 includes the vertical slots 130 opposite the vertical grooves 120, and parallel and aligned therewith such that an electronic circuit board is slidably insertable into the compartment 100 between the slot 130 and the groove 120 and is retained in an upright orientation. Thus, the vertical grooves 120 and vertical slots 130 cooperate to provide the retaining means for the electronic circuit boards 150. In other embodiments, the electronic circuit boards are retained inside the chassis 100 by other suitable retaining means, such as clips, fasteners, or an adhesive.

[0063] The chassis 100 is sized and dimensioned to receive a plurality of upright electronic circuit boards 150. In an embodiment, the chassis 100 has a substantially square cross section. With reference to FIG. 1, a chassis 100 with a square cross section is shown wherein the sidewalls 110, 112, 114, and 116 are substantially similar in dimensions. As will be shown below, when a heat-dissipating medium, such as a cooling fluid, is injected into the chassis at a central point of the bottom end thereof, a chassis with a substantially square cross section will provide for uniform cooling of the electronic circuit boards housed therein since the heat-dissipating medium may easily reach the boards at the edges thereof. Conversely, a chassis with a rectangular cross section in which the length is substantially larger than the breadth would locate some electronic circuit boards farther from the central point in which the heat-dissipating medium is injected. Accordingly, the heat-dissipating medium does not reach such electronic circuit boards, which may cause some of the components thereof to overheat.

[0064] In the embodiment shown in FIG. 1, the chassis 100 can house three vertically oriented electronic circuit boards 150A, 150B, and 150C (collectively "150") in a spacedapart arrangement. Each one of the plurality of circuit boards 150 includes a plurality of electronic components 152 connected thereto, and a connector 154 for providing electrical and communication connectivity to the board via a plurality of wires 156 operably connected with the connector 154. For example, the plurality of wires 156 may connect the board to a power supply, a bus controller, a network hub, or to any other electronic device known in the art. In some embodiments, the electronic circuit boards 150 also have a peripheral such as a hard drive or an optical drive 160 connected thereto. During operation, the components 152 produce heat. The open bottom end 127 permits the entry of a dielectric cooling liquid into the chassis compartment 100 in order to dissipate the heat generated during the operation of the electronic components 152 of the electronic circuit boards 150, as will be described further below. Similarly, the top end 125 permits the exit of the dielectric cooling liquid as it passes upwardly through the chassis 100 by convection for dissipating heat from the electronic components 152 of the electronic circuit boards 150.

[0065] While the chassis 100 shown in FIG. 1 is shown housing only three electronic circuit boards, a greater number of boards 150 may be inserted in the compartment 100. The number of boards inserted in the chassis may depend on the size of the chassis 100 and the size and/or type of the components 152 on the electronic circuit boards 150. For example, if the electronic components 152 produce excessive heat and require heat sinks in addition to the cooling by the dielectric cooling liquid, then the boards 150 need to be spaced apart. Conversely, if the components are smaller and do not produce much heat, then the chassis 100 shown may be adapted to house five electronic circuit boards.

[0066] In the shown embodiment, each of the chassis 100 shown in FIG. 1 has an open bottom end 127 for permitting a cooled heat-dissipating medium, such as a dielectric cooling liquid, to enter the chassis 100 for cooling the electronic components 152 of the electronic circuit boards 150 housed in the chassis 100. In other embodiments (not shown), the chassis has a closed bottom that includes one or more inlets for permitting the cooled heat-dissipating liquid to enter the chassis compartments therethrough.

[0067] Typically, server systems in data centers and the like are comprised of a plurality of boards. FIG. 2 shows a cluster of chassis 200 comprised of six chassis 100A-100F (collectively chassis 100) similar to the chassis 100 of FIG. 1. A smaller or larger number of chassis may be used in a cluster. The plurality of chassis 100 are separated from one another by a separator 102. In an embodiment, the chassis cluster 200 is formed as a six- chassis cluster from the outset wherein each chassis 100 is separated from an adjacent one by the separator 102. In another embodiment, the chassis cluster 200 is formed by coupling six individual chassis, such as chassis 100. The individual chassis 100 may be coupled by fasteners, welding, adhesives, or any other suitable means. In this embodiment, the separator 102 comprises the right wall 110 of one chassis abutting the left wall 114 of an adjacent chassis. FIG. 2 shows the electronic circuit boards 150 installed in all the chassis 100A-100F. In another embodiment, some chassis may have fewer boards, or no boards at all installed therein. The uniform size of the plurality of chassis 100 comprising chassis cluster 200, as well as having the same number of electronic circuit boards 150 in each chassis 100, provides for uniform flow of the heat-dissipating medium in each chassis 100. The uniform flow of the heat-dissipating medium ensures uniform heat dissipation from the plurality of components of the electronic circuit boards 150 in the chassis cluster 200.

[0068] FIGS. 3A-3C (collectively "FIG. 3") show a box header 300 for dispensing a cooled heat-dissipating medium, such as a dielectric cooling liquid, into a respective chassis as will be discussed below. The box header has a box header interior space, and a box header inlet 320 for receiving the heat-dissipating medium into the box header interior space therethrough. The box header also comprises a top wall 302 including a plurality of spacedapart box header orifices 310 of equal cross sectional areas for dispensing the cooled heatdissipating medium therethrough. In another embodiment, the top wall 302 includes a plurality of orifices having identical orifice patterns. In an embodiment, the box header 300 shown in FIG. 3 is of a generally cuboid shape having a hollow interior for receiving a cooling fluid. In other embodiments, the box header may have any other suitable shape as would be apparent to those of skill in the art. In the shown embodiment, the inlet 320 is a curved pipe. In other embodiments, the inlet can be a straight pipe, a hose, or any other suitable inlet means. In the embodiment shown, there are six orifices 310 in the top wall 302, each orifice 310 corresponding to a chassis 100 of the chassis cluster 200 of FIG. 2. In operation, the chassis cluster 200 is placed above the box header 300 such that each of the six orifices 310 dispenses the heat-dissipating medium into the chassis compartment 100 placed above it. In the embodiment shown, the chassis 100 has an open bottom 127 and the top wall 302 of the box header 300 has the same shape and size as the plurality of chassis bottom ends of the chassis cluster 200 so as to form a closed bottom end of all the chassis forming chassis cluster 200. Forming a closed bottom end prevents the heat-dissipating medium, such as the dielectric cooling fluid, from leaking out of the bottom end 127 of the chassis 100. As a result, the cooled heat-dissipating medium is directed upwardly towards the electronic circuit boards 150 for cooling the electronic components thereof. In another embodiment (not shown), the bottom ends of each of the chassis may be closed except for a central opening or aperture, which is aligned with a corresponding orifice of the box header to permit the cooled heat-dissipating medium to be dissipated into the chassis. In other embodiments, the box header has a different shape and/or dimensions as long as the orifices are arranged to dispense the cooled heat-dissipating medium into the bottom end of the plurality of chassis. [0069] The pressure of the heat-dissipating medium injected into the box header 300, via the inlet 320, rises inside the interior of the box header 300 as the interior becomes full. This rise in pressure drives the heat-dissipating medium out of the plurality of box header orifices 310 simultaneously and prevents the tunneling of the cooled heat-dissipating medium into some but not all box header orifices. Additionally, since all of the box header orifices 310 have the same cross sectional area, then the cooled heat-dissipating medium exiting the box header from each of the plurality of box header orifices 310 has the same flow rate. In a preferred embodiment, the size of the box header orifices 310 is selected such that the cooled heat-dissipating medium exits the box header 300 and enters the chassis at a high speed. The high speed by which the cooled heat-dissipating medium flows into each of the chassis creates a low-pressure region at the center of the chassis interior space (a pressure differential exists between the point that the cooled heat-dissipating medium flows into the chassis and the center of the chassis interior space, wherein the pressure at the point that the cooled heat-dissipating medium flows into the chassis is higher than the pressure at the center of the chassis interior space). The low-pressure region causes the bathing heat-dissipating medium in the interior chassis space to be drawn towards the center of the chassis interior, and mix with the cooled heat-dissipating medium entering the chassis. As a result, the temperature of the heat-dissipating medium in the lower region of the chassis becomes substantially even and cooler than a temperature of the bathing heat-dissipating medium in other regions inside the chassis. The cooled heat-dissipating medium rises by convection in the cluster thus cooling the electronic components of the electronic circuit boards as discussed.

[0070] FIGS. 4A-4C (collectively "FIG. 4") depict an example of a spacer 400. The spacer 400 has a central longitudinal plate 405 forming the length of the spacer 400, and five fins 410A-410E (collectively "410"), arranged to form spaces 420 with the central longitudinal plate 405 and each other. As depicted herein, the fins 410 are parallel to one another. As depicted herein the fins 410 are rectangular in shape. For example, the plurality of fins 410 are arranged to form four spaces 420 therebetween with each space bounded from three sides; the central longitudinal plate 405 and two fins 410. The two end fins 410A and 410E form spaces bounded from two sides; the central longitudinal plate 405 and either fin 410A or 410E. The spacer 400 has similar dimensions to chassis 200, such that when placed on top of a chassis cluster 200, the parallel fins 210 coincide with the separators 102, which separate the chassis 100. In other embodiments, the fins 410 can be angled to one another and may be curved. In other embodiments, other suitable shapes of spacers can be used.

[0071] FIG. 5 depicts a chassis cluster 200 and a spacer 400 placed on top of the chassis cluster 200. When placed on top of chassis cluster 200, the four spaces 420 of spacer 400 are aligned with the open top ends 125 of the central four chassis compartments 100B-100E of chassis cluster 200. This is done by aligning the fins 410 with the separators 102, as discussed above. Similarly, the space formed by each of the two end fins 410A and 410E with the central longitudinal plate 405, is aligned with the leftmost compartment 100A and the rightmost compartment 100F, respectively. Accordingly, when a warmed heatdissipating medium exits from each of the open top ends 125 of the chassis 100A-100F, the fins 410A-410E isolate the warmed heat-dissipating medium from each of chassis components 100 and deflects it away from the chassis cluster 200. As would be appreciated by a person skilled in the art, the warmed heat-dissipating medium dispensed from each chassis 100 is split into two streams by the central longitudinal plate 405. Advantageously, as will be seen with reference to the system 1000 of FIG. 8, the spacer 400 serves to deflect the warmed heat-dissipating medium exiting from a lower chassis cluster away from the box header of an upper chassis stacked on top of the lower chassis.

[0072] In another embodiment (not shown), the box header may be supported by supports extending from the sidewalls of the tank in which they are installed. The support may be adjusted in height to provide spacing between a box header and the chassis cluster positioned under that box header, thus averting the need for a spacer.

[0073] An immersion cooling system in accordance with the present disclosure comprises at least one chassis cluster disposed inside a tank filled with a bathing heat-dissipating medium, such as a dielectric cooling fluid. In some embodiments, the tank is cuboid in shape such as tank 600 of FIG. 6A. The tank 600 has a top end 640, a bottom end 660, and a sidewall 630 extending between the top end 640 and the bottom end 660, the sidewall forming an interior space. The tank 600 is adapted to be filled with a bathing heat-dissipating medium such as a dielectric cooling fluid. In an embodiment, the top end 640 of the tank 600 is open. In another embodiment (not shown), the top end is closed but has one or more apertures to permit feeder means therethrough for providing a cooled heat dissipating medium into the tank. The tank 600 also has at least one outlet 620 formed in the sidewall 630 and is in fluid communication with the interior space for dispensing the warmed heat- dissipating medium out of the tank 600. In an embodiment, the tank is sized to receive a plurality of chassis clusters. For example, FIG. 6B shows four chassis clusters 200 shown placed side by side in tank 600. Each of the clusters 200 is shown having six chassis each holding three electronic circuit boards.

[0074] FIG. 7 shows an immersion cooling system 900, in accordance with an embodiment of the present disclosure. The system 900 comprises a tank 600, similar to the tank of FIG. 6A. The tank 600 has a tank bottom 660, and a tank sidewall 630 extending from the tank bottom and forming a tank interior space therewith for receiving a bathing heatdissipating medium 605. The tank 600 has an outlet 620 formed in the tank sidewall 630 for dispensing the warmed heat-dissipating medium 605 therethrough. A box header 300, or a box header that is similar to the box header of FIG. 3, is disposed in the tank interior space of the tank 600. The box header 300 has a box header interior space, and a box header inlet 320 for receiving a cooled heat-dissipating medium into the box header interior space therethrough. The box header 300 has a top wall 302 including six spaced-apart box header orifices 310 of equal cross sectional areas for dispensing the cooled heat dissipating medium therethrough. A cluster of chassis 200, or a cluster that is similar to the one depicted in FIG. 2, comprising six chassis 100 is disposed on the box header 300. Each of the chassis 100 has a top end, a bottom end, and a chassis sidewall extending between the chassis top end and the chassis bottom end. The chassis sidewall forms a chassis interior space adapted for receiving a plurality of electronic circuit boards in an upright orientation. The six spaced- apart box header orifices 310 are arranged to each dispense the cooled heat-dissipating medium into the chassis bottom end of a respective on of the six chassis forming the chassis cluster 200. The box header 300 is configured to cause a buildup of pressure of the heatdissipating medium 605 in the box header interior space such that the heat-dissipating medium is dispensed into the chassis bottom end of each one of the six chassis 100 with the same flow rate. This provides for uniform cooling of the plurality of electronic boards inside each chassis 100.

[0075] In some embodiments, the immersion cooling system, such as the immersion cooling system 900 depicted in Fig. 7, further comprises a pump 700, a cooling means such as heat exchanger 800, and feeder means such as pipe 550. The pump 700 is in fluid communication with the tank outlet 620. The cooling means, such as heat exchanger 800, is in fluid communication with the pump 700 via a pipe 710. The feeder means, such as pipe 550, is in fluid communication with the cooling means, such as heat exchanger 800, via the inlet 520 and feeder means 550, and is in fluid communication with the box header inlet 320. The warmed heat-dissipating medium dispensed from the tank outlet 620 is first drawn by the pump 700 and driven by the pump 700 through the cooling means such as heat exchanger 800 to produce a cooled heat-dissipating medium. The cooled heat-dissipating medium is then dispensed through the six box header orifices 310 into the six chassis 100.

[0076] In an embodiment, the six orifices 310 are sized to dispense the cooled heatdissipating medium into the bottom end of each one of the six chassis with a velocity, which creates a low-pressure region in a center of the chassis interior space of each one of the six chassis. The low-pressure region causes the bathing heat-dissipating medium 605 present in the chassis interior space of each of the six chassis to be drawn towards the center of the classis interior space and mix with the cooled dispensed heat-dissipating medium thus producing a heat-dissipating medium of a lower and even temperature in each one of the six chassis. The heat-dissipating medium of the lower and even temperature then rises by convection in each of the six chassis thus cooling the electronic components of the plurality of boards housed in the chassis.

[0077] In an embodiment, the top wall 302 of the box header 300 is arranged to close the chassis bottom of each of the six chassis for preventing the bathing heat-dissipating medium 605 from leaking out from the chassis bottom end.

[0078] In an embodiment, the outlet 620 of the tank is located at a level in the sidewall 630, which is above the chassis top end of each one of the six chassis for dispensing the warmed heat-dissipating medium 605, which exits the top ends of the six chassis, out of the tank 600.

[0079] FIG. 8 shows an immersion cooling system 1000, in accordance with another embodiment of the present disclosure. The system 1000 comprises a tank 600, similar to the tank of FIG. 6A. The tank 600 has a tank bottom 660, and a tank sidewall 630 extending from the tank bottom and forming a tank interior space therewith for receiving a bathing heatdissipating medium 605. The tank 600 has an outlet 620 formed in the tank sidewall 630 for dispensing a warmed heat dissipating medium 605 therethrough. A first box header 300A, similar to the box header of FIG. 3 is disposed in the tank interior space of the tank 600. The first box header 300A has a box header interior space, and a first box header inlet 320A for receiving a cooled heat-dissipating medium into the box header interior space therethrough. The first box header 300A has a top wall 302A including six spaced-apart box header orifices 310A of equal cross sectional areas for dispensing the cooled heat dissipating medium therethrough. A first cluster of chassis 200A, similar to the cluster of FIG. 2, comprising six chassis 100 is disposed on the first box header 300A. Each of the chassis 100 has top end, a bottom end, and a chassis sidewall extending between the chassis top end and the chassis bottom end. The chassis sidewall forms a chassis interior space adapted for receiving a plurality of electronic circuit boards in an upright orientation. The six spacedapart box header orifices 310A are arranged to each dispense the cooled heat-dissipating medium into the chassis bottom end of a respective one of the six chassis forming the first chassis cluster 200A. The first box header 300A is configured to cause a buildup of pressure of the cooled heat-dissipating medium 605 in the box header interior space such that the cooled heat-dissipating medium is dispensed into the chassis bottom end of each one of the six chassis 100 with the same flow rate. This provides for uniform cooling of the plurality of electronic boards inside each chassis 100 of the cluster 200A.

[0080] A second box header 300B, similar to the box header 310A is disposed in the tank interior space of the tank 600 above the first chassis cluster 200A and spaced vertically therefrom to allow the heated heat-dissipating medium exiting the top end of the first chassis cluster 200A to move upwards around the second box header 300B. The second box header 300A has a box header interior space, and a second box header inlet 320B for receiving a cooled heat-dissipating medium into the box header interior space therethrough. The second box header 300B has a top wall 302B including six spaced-apart box header orifices 310B of equal cross sectional areas for dispensing the cooled heat-dissipating medium therethrough. A second cluster of chassis 200B, similar to the first cluster 200A, comprising six chassis 100 is disposed on the second box header 300B. Each of the chassis 100 has top end, a bottom end, and a chassis sidewall extending between the chassis top end and the chassis bottom end. The chassis sidewall forms a chassis interior space adapted for receiving a plurality of electronic circuit boards in an upright orientation. The six spaced-apart box header orifices 310B are arranged to each dispense the cooled heat-dissipating medium into the chassis bottom end of a respective on of the six chassis forming the second chassis cluster 200B. The second box header 300B is configured to cause a buildup of pressure of the heatdissipating medium 605 in the box header interior space such that the heat-dissipating medium is dispensed into the chassis bottom end of each one of the six chassis 200 with the same flow rate. This provides for uniform cooling of the plurality of electronic boards inside each chassis 200 of the cluster 200B. [0081] In an embodiment, the immersion cooling system 1000 further comprises a spacer 400 disposed above the first chassis cluster 200A and below the second box header 300B for vertically spacing the second box header from the first chassis cluster. In an embodiment, the spacer comprises a plurality of parallel fins spaced be aligned with the sidewalls separating adjacent chassis in the first chassis cluster, as discussed earlier with reference to FIG. 4.

[0082] In an embodiment, the immersion cooling system 1000 further comprises a pump, a cooling means, a pipe header, and first and second feeder means. The pump 700 is in fluid communication with the tank outlet 620. The cooling means, such as heat exchanger 800 is in fluid communication with the pump 700 via a pipe 710. The pipe header has an inlet 520 in fluid communication with the cooling means. The pipe header has a pipe header body 500 including a first pipe header orifice 510A having a first cross sectional area, and a second pipe header orifice 510B having a second cross sectional area equal to the first cross sectional area. The pipe header body 500 is configured to cause a buildup of pressure therein such that the cooled heat-dissipating medium is dispensed from the first pipe header orifice 510A and the second pipe header orifice 510B with the same flow rate. A first feeder means, such as pipe 550A, is in fluid communication with the first pipe header orifice 510A and the first box header inlet 320A. A second feeder means such as pipe 550B is in fluid communication with the second pipe header orifice 510B and the second box header inlet 320B.

[0083] The warmed heat-dissipating medium dispensed from the tank outlet 620 is first drawn by the pump 700 and driven by the pump 700 through the cooling means, such as heat exchanger 800, to produce a cooled heat-dissipating medium. The cooled heatdissipating medium is then driven through the pipe header inlet 520 into the pipe header body 500. The cooled heat-dissipating medium is dispensed through the first plurality of box header orifices 310A into the six chassis 100 of the first chassis cluster 310A, and dispensed through the second plurality of box header orifices 310B into the six chassis of the second chassis cluster 310B.

[0084] The pipe header dispenses the cooled heat-dissipating medium through the respective pipe header orifices with the same flow rate. Similarly, the box headers dispense the cooled heat-dissipating medium through the respective box header orifices with the same flow rate. Accordingly, the cooled heat-dissipating media dispensed into all of the chassis of both the first chassis cluster 200A and the second chassis cluster 200B have the same cooling effect. Advantageously, the electronic circuit boards in all of the chassis of the system 1000 are uniformly cooled. The immersion cooling system disclosed presents significant advantages over the prior art systems in which the heat-dissipating medium is injected at the bottom of an immersion tank and rises by convection in the entire tank. In those prior art systems, as the heat-dissipating medium rises by convection in the tank, its temperature continually rises. As such, the components of the electronic circuit boards located higher in the tank are not sufficiently cooled as they come into contact with a warmed heat-dissipating medium having a temperature which is too high to provide sufficient cooling.

[0085] In an embodiment, the six box header orifices 310A and the six box header orifices 310B are sized to dispense the cooled heat-dissipating medium into the bottom end of each chassis of the respective chassis clusters (200A and 200B) with a velocity, which creates a low-pressure region in a center of the chassis interior space. The low-pressure region causes the bathing heat-dissipating medium 605 present in the chassis interior space of each of the chassis to be drawn towards the center of the classis interior space and mix with the cooled dispensed heat-dissipating medium thus producing a heat-dissipating medium of a lower and even temperature in each one of the six chassis. The heat-dissipating medium of the lower and even temperature then rises by convection in each of the chassis thus cooling the electronic components of the plurality of boards housed in the chassis.

[0086] In an embodiment, the top wall 302A of the first box header 300A is arranged to close the chassis bottom end of each one of the first plurality of chassis of the first chassis cluster 200A, and the top wall 302B of the second box header 300B is arranged to close the chassis bottom end of each one of the second plurality of chassis of the second cluster 200B.

[0087] In an embodiment, the outlet 620 of the tank is at a level in the tank sidewall 630 that is above the chassis top end of each one of the second plurality of chassis of the second chassis cluster 200B.

[0088] In an embodiment, the first plurality of chassis comprising chassis cluster 200A and the second plurality of chassis comprising chassis cluster 200B each further comprises a retaining means for retaining at least some of the first and second plurality of electronic circuit boards in the chassis interior space of at least some of the first and second plurality of chassis in the upright orientation.

[0089] FIG. 9 depicts a method 1100 of immersion cooling of a plurality of electronic boards housed in a plurality of chassis, such as the chassis cluster 200 of FIG. 7. The plurality of chassis have similar dimensions and are disposed in a tank such as tank 600 of FIG. 7. At step 1110, a cooled heat-dissipating medium is dispensed with the same flow rate into a bottom end of each of the plurality of chassis such that the cooled heat-dissipating medium cools the plurality of electronic boards and exits each of the plurality of chassis at a top end thereof as a warmed heat-dissipating medium. At step 1120, the warmed heat-dissipating medium is drawn out of the tank. At step 1130, the warmed heat-dissipating medium, drawn out of the tank, is cooled to produce the cooled heat-dissipating medium. At step 1140 the cooled heat-dissipating medium is passed back to be dispensed into the bottom end of each one of the plurality of tasks. The process then restarts at step 1110.

[0090] In an embodiment, passing the cooled heat-dissipating medium back to be dispensed into the bottom end of each of the plurality of chassis comprises dispensing the cooled heat-dissipating medium from a plurality of orifices such as orifices 310 of FIG. 7. Each of the plurality of orifices 310 is arranged to dispense the cooled heat-dissipating medium into one of the plurality of chassis, such as chassis 100 of chassis cluster 200 in FIG. 7.

[0091] FIG. 10 depicts a method 1200 of immersion cooling of a first plurality of electronic boards housed in a first plurality of chassis, such as the plurality of chassis comprising chassis cluster 200A of FIG. 8, and a second plurality of electronic boards in a second plurality of chassis, such as the plurality of chassis comprising chassis cluster 200B of FIG. 8. The first and second chassis clusters are disposed in a tank, such as tank 600 of FIG. 8. At step 1210, a cooled heat-dissipating medium is dispensed into a bottom end of each of the first and second plurality of chassis such that the cooled heat-dissipating medium cools the first and second plurality of boards and exits each of the first and second plurality of chassis at a top end thereof as a warmed heat-dissipating medium. At step 1220, the warmed heat-dissipating medium is drawn out of the tank. At step 1230, the warmed heatdissipating medium is cooled to produce the cooled heat-dissipating medium. At step 1240, the cooled heat-dissipating medium is passed to a pipe header. At 1250, the cooled heatdissipating medium is passed from the pipe header to each of a first box header, such as box header 300A disposed under the first chassis cluster 200A and the second box header such as box header 300B disposed under the second chassis cluster 200B.

[0092] The above-described embodiments are intended to be examples of the present disclosure and alterations and modifications may be effected thereto, by those of skill in the art, without departing from the scope of the invention, which is defined solely by the claims appended hereto.