Systems for cooling electronic components in a sealed computer chassis

A computing device includes a sealed computer chassis housing, a heat source, a heat spreader, and a thermal pad. The sealed computer chassis housing, defines an interior space and an exterior surface with a heat sink for the interior space. The heat source is disposed within the interior space. The heat spreader includes a plurality of thermally-conductive protrusions coupled to one or more components of the heat source by an intermediate thermally conductive layer. The thermal pad is positioned above and in thermal contact with the heat spreader. The thermal pad is positioned to contact an interior wall of the sealed computer chassis housing opposite to the heat sink.

FIELD OF THE INVENTION

The present disclosure generally relates to computing systems. More specifically, the present disclosure relates to computing systems for cooling electronic components in a sealed computer chassis.

BACKGROUND

Computing systems, such as those used for outdoor electronic telecommunications, require increasingly higher computing performance. Computing systems used in an outdoor environment need to be placed inside dustproof and waterproof housings. For outdoor electronic computing equipment, the housing for the computing systems typically acts as a heat sink for cooling the internal heat-generating electronic components. High-performance electronic components in computing systems, such as heat-generating components connected to high-performance expansion cards, cause increased heat generation within a computer chassis of such computing systems.

SUMMARY

According to one embodiment, a computing system includes a scaled computer chassis housing, a plurality of heat-generating components, a heat spreader, and a thermal pad. The sealed computer chassis housing defines an interior space and an exterior surface with a heat sink for the interior space. The plurality of heat-generating electronic components are disposed within the interior space and electrically coupled to one or more expansion cards electrically connected on a main hoard. The plurality of heat-generating electronic components include one or more microprocessor and one or more memory devices. The heat spreader includes a plurality of thermally-conductive protrusions coupled to the one or more microprocessors or one or more memory devices by an intermediate thermally conductive layer. The thermal pad is positioned above and in thermal contact with the heat spreader. The thermal pad is positioned adjacent to an interior wall of the sealed computer chassis housing opposite the heat sink.

According to another embodiment, a computing device includes a sealed computer chassis housing, a heat source, a heat spreader, and a thermal pad. The sealed computer chassis housing defines an interior space and an exterior surface with a heat sink for the interior space. The heat source is disposed within the interior space. The heat spreader includes a plurality of thermally-conductive protrusions coupled to one or more components of the heat source by an intermediate thermally conductive layer. The thermal pad is positioned above and in thermal contact with the heat spreader. The thermal pad is positioned to contact an interior wall of the sealed computer chassis housing opposite the heat sink.

In further aspects of the embodiments, the heat spreader includes one or more heat pipes. In some embodiments, the heat pipes are disposed on to top surface of the heat spreader opposite w the plurality of thermally-conductive protrusions. The heat from the heat source or the one or more microprocessors or one or more memory devices is distributed along the heat spreader. In further aspects of the embodiments, the heat spreader includes a vapor chamber on a top surface of the heat spreader opposite to the plurality of thermally-conductive protrusions. In some embodiments, the heat from the one or more microprocessor or the one or more memory devices is distributed along the heat spreader.

In further aspects of the embodiments, the heat sink includes a plurality of fins protruding orthogonally to the exterior surface of the sealed computer or server chassis housing, in some embodiments, the plurality of fins is oriented such that heat transferred to the heat sink rises out of air gaps between adjacent fins. In yet further aspects of the embodiments, the heat sink includes one heat sink disposed on the exterior surface of a first side of the sealed computer or server chassis housing and a second heat sink disposed on the exterior surface of a second side of the sealed computer or server chassis housing.

In further aspects of the embodiments, a height of the plurality of fins is greater than about five-times a width of a gap between adjacent spaced fins. In some embodiments, at least one expansion card is an expansion card for enhancing the computing system performance. In some embodiments, the intermediate thermally-conductive layer includes thermally-conductive grease. In some embodiments, the plurality of thermally conductive protrusions includes protrusions of at least two different heights.

The present disclosure is susceptible to various modifications and alternative forms. Some representative embodiments have been shown by way of example in the drawings and will be described in detail herein. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed. Rather, the disclosure is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION

The various embodiments are described with reference to the attached figures, where like reference numerals are used throughout the figures to designate similar or equivalent elements. The figures are not drawn to scale, and they are provided merely to illustrate the instant invention. It should be understood that numerous specific details, relationships, and methods are set forth to provide a full understanding. One having ordinary skill in the relevant art, however, will readily recognize that the various embodiments can be practiced without one or more of the specific details, or with other methods. In other instances, well-known structures or operations are not shown in detail to avoid obscuring certain aspects of the various embodiments. The various embodiments are not limited by the illustrated ordering of acts or events, as some acts may occur in different orders and/or concurrently with other acts or events. Furthermore, not all illustrated acts or events are required to implement a methodology in accordance with the present invention.

Elements and limitations that are disclosed, for example, in the Abstract, Summary, and Detailed Description sections, but not explicitly set forth in the claims, should not be incorporated into the claims, singly, or collectively, by implication, inference, or otherwise. For purposes of the present detailed description, unless specifically disclaimed, the singular includes the plural and vice versa. The word “including” means “including without limitation.” Moreover, words of approximation, such as “about,” “almost,” “substantially,” “approximately,” and the like, can be used herein to mean “at,”, “near,” or “nearly at,” or “within 3-5% of,” or “within, acceptable manufacturing tolerances,” or any logical combination thereof, for example.

With regards to the present disclosure, the terms “computing system” or “computing device” refer to any electronically-powered or battery-powered equipment that has hardware, software, and/or firmware components, where the software and/or firmware components can be configured, for operating features on the device. The term “coupled” means connected, whether directly or indirectly through intervening components, and is not necessarily limited to physical connections. The connection can be such that the objects are permanently connected or releasably connected. The term “substantially” is defined to be essentially conforming to the particular dimension, shape, or other word that substantially modifies, such that the component need not be exact. For example, substantially cylindrical means that the object resembles a cylinder, but can have one or more deviations from a true cylinder.

The present technology relates to a computing device including a heat source disposed in a server chassis housing or a computer chassis housing. The computing device has a sealed chassis housing that defines an interior space, along with an exterior surface with a heat sink. The heat sink can include spaced fins protruding orthogonally to an exterior surface of the housing. The spaced fins draw heat away from heat sources disposed in the interior space, such as electronic components. The chassis housing is preferably dustproof and waterproof such that the electronic components in the interior space of the computer chassis housing remain operable and do not become damaged by the elements in an outdoor environment, such as when positioned on a mounting pole for telecommunication equipment. A heat spreader having, for example, a plurality of thermally conductive protrusions, is coupled to One or more of the heal sources by an intermediate thermally-conductive layer. In addition, a thermal pad may be positioned above and in thermal contact with the heat spreader. For example, the thermal pad may be positioned to be in physical contact with an interior wall of the computer chassis housing such that it is opposite the heat sink on the exterior surface.

The present technology is contemplated to be beneficial in cooling closed interior spaces having heat sources (e.g., heat-generating electronic components), that do not bring in, or circulate, cooler ambient air to replace warmer air in the interior space. In some implementations, the interior space may not be entirely closed but may have limitations on bringing in or circulating cooling air.

The present technology provides a solution to heat dissipation issues for heat-generating high-performance outdoor computing equipment where forced convection is not a desirable option. For example, it can be desirable to have a plurality of high-performing electronic components within a chassis housing of an outdoor computing device in fifth-generation mobile network architecture. The present technology provides a unique thermal solution for equipment in which a traditional forced convection system cannot be effectively used to cool the heat-generating components.

In some implementations, the computing system is a finless cooling system with two or more high-performance expansion cards, such as peripheral component interface express (PCIe) cards with heat-generating processing units. The computer chassis housing acts as a heat sink for cooling the heat-generating processing units located inside the computer chassis housing. The tailless cooling system can include thermal pad(s), spaced fins protruding from the exterior surface of the chassis housing, thermally conductive grease or paste, a heater spreader, and thermally conductive protrusions extending from the heat spreader. It is contemplated that such a finless cooling system can dissipate heat at a rate of approximately 100 Watts or more (e.g., greater than about 340 BTU/hour).

Referring now toFIG. 1A, a top perspective view of an exemplary computer chassis housing100is depicted for outdoor use. The computer chassis housing100is sealed and includes an exterior surface115and an interior space (not shown). A plurality of spaced fins150is disposed on the exterior surface and acts as a heat sink. The computer chassis housing100includes at least two housing enclosure components110,120that are secured together to form a dustproof and waterproof interface157generally along the x-z plane between the two housing enclosure components110,120. The computer chassis housing100protects electronic con components disposed within the interior space of the chassis housing100.

The plurality of spaced fins ISO are spaced along the exterior surface115, generally parallel to the x-z plane of the housing enclosure component110. The plurality of spaced fins150may similarly be positioned on the exterior surface115of the housing enclosure component120, as partially depicted and discussed in more detail below forFIG. 1C. During operation of electronic components within the computer chassis housing100, ambient air will be heated at the exterior surface115of the computer chassis housing100and flow through air gaps (e.g., gap155) between adjacent fins. Natural convection due to the pressure differential between the heated ambient air in the gaps and the surrounding ambient air will drive the heated air upwards and away from the exterior surfaces115. In some implementations, the computer chassis housing100has a width along the x-axis of approximately six to seven inches or greater, which allows a sufficient number of fins150to be placed on the exterior surface115of the housing enclosure components110,120to meet the heat dissipation demands of heat-generating electronic components (not shown) disposed within the computer chassis housing100.

Referring toFIG. 1B, a top perspective view of the interior space130of the exemplary computer chassis housing100ofFIG. 1A, is depicted.FIG. 1Bshows the computer chassis housing100with the housing enclosure component110removed and a seal156disposed at the interface157between housing enclosure components110(not shown),120providing a dustproof and waterproof environment for the interior space130. A plurality of exemplary electronic components, including a main board140, such as a motherboard, and multiple high-performance expansion cards145a,145b,145care further depicted.

Referring toFIG. 1C, a side view of the exemplary computer chassis housing100ofFIG. 1Ais depicted. The two housing enclosure components110,120have the plurality of spaced fins150protruding orthogonally away from the exterior surface115of the housing enclosure component110. In some implementations, a second plurality of spaced fins152protrude orthogonally away from an exterior surface125of the housing enclosure component120. The plurality of spaced fins150,152are oriented such that heat transferred to the heat sink created by the spaced fins150,152rises taut of the air gaps155between adjacent spaced fins150,152. To allow for air flow in the air gaps155between adjacent fins150,152and provide for natural convection, in some implementations the width of the air gap155, denoted as G, is in the range of about 0.2 inches to 0.6 inches and the spaced fin height, h, is in the range of about two inches to about eight inches. In some implementations, the height, h, of the spaced fins150,152is greater than about five-times the width G of the air gap155between adjacent spaced fins150,152. The width of each individual fin of spaced fins150,152can range from about 0.03 inches to 0.2 inches.

Turning now toFIG. 2, a top perspective view of a plurality of expansion cards240,250,260coupled to a main board210, is depicted. The main board210is disposed in the interior space130of the sealed computer chassis housing100inFIG. 1A. The exemplary expansion cards240,250,260may include any of a number of heat-generating electronic components. For example, the expansion cards240,250,260may he PCIe cards having microprocessors245,255,265and memory devices respectively. The microprocessors245,255,265typically generate a large amount of heat, and thus, must be cooled for operation of the expansion cards240,250,260. In one example, the microprocessors245,255,265may be field-programmable gate arrays (FPGAs).

FIG. 3Adepicts a top perspective view of an exemplary expansion card300, similar to the expansion cards240,250,260. The expansion card300includes heat-generating electronic chip components310,320,330,340coupled thereto. The electronic chip components310,320,330,340have non-uniform heights, as exemplified by electronic chip components320,330compared to the electronic chip component310. The electronic chip component310is a primary microprocessor chip and generates a large amount of heat. The other electronic chip components320,330,340may perform other secondary operations and generate less heat than the main chip.

FIG. 3Bdepicts a top perspective view of the exemplary expansion card300as visible through a heat spreader350partially covering the expansion card300. The heat spreader350has a planar top surface352that does not include fins and a bottom surface354(seeFIG. 3C). The heat spreader350assists with the transfer of heat energy away from each of the heat-generating electronic components310,320,330,340to heat sink, such as the plurality of spaced fins150(FIG. 1A-1C). The heat spreader350may be fabricated from any conductive material of high thermal conductivity, such as copper, aluminum, or alloys thereof.

FIG. 3Cdepicts a bottom perspective view of the heat spreader350ofFIG. 3Bincluding thermally-conductive protrusions361,362,363,364extending from the bottom surface354of the heat spreader350. The thermally-conductive protrusions361,362,363,364are fabricated so that when the heat spreader350is placed over the expansion card300, one or more of the thermally-conductive protrusions361,362,363,364align vertically and horizontally with the top surfaces of the heat-generating electronic components310,320,330,340. The heat-generating electronic components can include, for example, microprocessors or memory devices. The thermally-conductive protrusions361,362,363,364can be coupled to the heat-generating electronic components310,320,330,340by an intermediate thermally-conductive layer, such as a thermal pad, thermal grease, or thermal paste. The thermally-conductive protrusions361,362,363,364can be fabricated from the same thermally-conductive material as the heat spreader350.

Turning now toFIGS. 4A and 4B, cross-sectional diagrams of exemplary computing systems400,401, are depicted. Referring toFIG. 4A, the computing system400includes a computer chassis housing410comprising a top housing component412, a bottom housing component414, and side walls416,418. The interfaces between the housing components412,414,416,418are sealed such that the computer chassis housing provides a dustproof and waterproof enclosure for electronic components440a-d,450a-ddisposed in an interior space420of the computer chassis housing. Heat spreaders442,452include thermally-conductive protrusions444a-d,454a-dthat assist with transferring heat from their respective electronic components440a-d,450a-dto thermal pads443,453and then to the top housing component412and the bottom housing component414, respectively. The thermally-conductive protrusions444a-d,454a-dcan be coupled to their respective electronic components440a-d,450a-dusing, for example, thermally-conductive pads441a-c,451b-d,thermally-conductive grease441d,451a,or combinations thereof. Other thermally-conductive coupling options are also contemplated within the scope of this disclosure.

The top housing component412and the bottom housing component414include a plurality of spaced fins460,470extending orthogonally from exterior surfaces462,474of the top housing component412and the bottom housing component414, respectively. Collectively, the electronic components440a-d,450a-dcan be referred to as heat sources. The combination of the plurality of spaced fins460, the top housing component412, the thermal pad443, the heat spreader442, the thermally-conductive protrusions444a-d,and the thermally-conductive layers441a-dcan collectively, or in part, be referred to as a first heat sink for the beat sources440a-d.Similarly, the combination of the plurality of spaced fins470, the bottom housing component414, the thermal pad453, the heat spreader452, the thermally-conductive protrusions454a-d,and the thermally-conductive layers451a-dcan collectively, or in part, be referred to as a second heat sink for the heat sources450a-d.It is contemplated that the computing system400can include different configurations of the described electronic component(s), space fins, housing components, thermal pad(s), heat spreader(s), thermally conductive protrusion(s), and thermally-conductive layer(s) within the interior space420.

Referring toFIG. 4B, the computing system401includes similar components as described for computing system400, except computer chassis housing411has a different exemplary housing configuration. The computer chassis housing411includes a first unitary housing enclosure component413and a second unitary housing enclosure component415. The interface between the first and second housing enclosure components413,415is sealed such that the computer chassis housing411provides a dustproof and. waterproof enclosure for electronic components disposed within an interior space of the computer chassis housing411.

The two-sided configuration with electronic components connected on both sides of a printed circuit board can provide a more efficient and more powerful computing system, while minimizing the number of sealed computer chassis housings. This can be beneficial, for example, in dense telecommunications networks.

Referring toFIG. 5A, a top perspective view of an exemplary expansion card500with heat-generating electronic components, such as the electronic components310,320,330,340(FIG. 3A), is depicted. The expansion card500further includes a top surface552, a bottom surface554, a heat spreader550with one or more beat pipes555,556positioned along the planar top surface552of the heat spreader550. The heat spreader550assists with the transfer of heat energy away from the heat-generating electronic components to a heat sink.

Referring toFIG. 5B, a bottom perspective view of the heat spreader550ofFIG. 5A, is depicted. The heat spreader550includes thermally-conductive protrusions561,562,563,564extending from the bottom surface554of the heat spreader550. The thermally-conductive protrusions561,562,563,564are fabricated so that when the heat spreader550is placed over the expansion card500, one or more of the thermally-conductive protrusions561,562,563,564align vertically and horizontally with the top surfaces of the heat-generating electronic components (e.g., similar to electronic components310,320,330,340inFIG. 3A). The thermally-conductive protrusions561,562,563,564can be coupled to the heat-generating electronic components by an intermediate thermally-conductive layer, such as a thermal pad, thermal grease, or thermal paste, as described inFIG. 4. The thermally-conductive protrusions561,562,563,564can be fabricated from the same thermally-conductive material as the heat spreader550.

The heat pipes555,556inFIG. 5Aare disposed on the top surface552of the heat spreader550opposite to the plurality of thermally-conductive protrusions561,562,563,564such that heat from the heat-generating electronic components (e.g., similar to electronic components310,320,330,340inFIG. 3A) is distributed along the heat spreader550. The heat pipes555,556are fabricated from a material having a heat conductivity coefficient higher than the heat conductivity coefficient of the heat spreader550, such that the heat is more uniformly distributed along the heat spreader550, It is contemplated that the heat conductivity coefficient of the heat pipes555,556is within a range of about 1,500 to 50,000 watts per meter-kelvin (W/m-K.). In some implementations, the heat conductivity coefficient of the heat spreader is within a range of about 100 to 500 W/m-K.

The heat pipes555,556combine both the concepts of thermal conductivity and phase transition to effectively transfer heat between two solid interfaces. For example, at a hot interface of the heat pipe555,556, a liquid in contact with a thermally-conductive solid surface turns into a vapor by absorbing heat from that surface. The vapor then travels along the heat pipes555,556, to the cold interface and condenses back into a liquid, releasing the latent heat. The liquid then returns to the hot interface through either capillary action, centrifugal force, or gravity and the cycle repeats. Due to the very high heat transfer coefficients for boiling and condensation, the heat pipes555,556are highly efficient thermal conductors, when incorporated into the systems described herein.

Turning now toFIG. 6A, a top perspective view of an exemplary expansion card600with heat-generating electronic components, such as the electronic components310,320,330,340(FIG. 3A), is depicted. The expansion card600further includes a heat spreader650with a vapor chamber655positioned along a planar top surface652and a bottom surface654(seeFIG. 6B). The heat spreader650assists with the transfer of heat energy away from the heat-generating electronic components to the heat sink. In some implementations, it is contemplated that the vapor chamber655can have a heat conductivity coefficient that is within a range of about 1,500 to 50,000 W/m-K.

Referring toFIG. 6B, a bottom perspective view of the heat spreader650ofFIG. 6A, is depicted. The heat spreader650includes thermally-conductive protrusions661,662,663,664extending from the bottom surface654of the heat spreader650. The thermally-conductive protrusions661,662,663,664are fabricated so that when the heat spreader650is placed over the expansion card600, one or more of the thermally-conductive protrusions661,662,663,664align vertically and horizontally with the top surfaces of the heat-generating electronic components (e.g., similar to electronic components310,320,330,340inFIG. 3A). The thermally-conductive protrusions661,662,663,664can be coupled to the heat-generating electronic components by an intermediate thermally-conductive layer, such as a. thermal pad, thermal grease, or thermal paste, as described inFIG. 4. The thermally-conductive protrusions661,662,663,664can be fabricated from the same thermally-conductive material as the heat spreader650.

The vapor chamber655inFIG. 6Ais disposed on the top surface652of the heat spreader650opposite to the plurality of thermally conductive protrusions,661,662,663,664such that heat from the heat-generating electronic components (e.g., similar to electronic components310,320,330,340) is distributed along the heat spreader650.

Referring toFIG. 6C, a cross-sectional perspective view of the vapor chamber655ofFIG. 6Ais depicted, The heat spreader650(seeFIG. 6A) is in direct contact with an underside656of the vapor chamber655. A thermal pad, such as the thermal pad443,453described for example inFIG. 4, places the vapor chamber655in thermal contact with the finned portion of the heat sink (e.g., similar to the plurality of fins460or470inFIG. 4) that dissipate heat to ambient air. The vapor chamber655includes a working fluid (e.g., water) that vaporizes in a chamber657and travels to cooler areas of the vapor chamber655. The finned portion of the heat sink absorbs heat from the vapor chamber655, thereby causing the vapor in the chamber657to condense into liquid form. This liquid is reabsorbed by a wick material and distributed, through capillary action, to the underside656of the vapor chamber655. This above steps of vaporization and condensation forms a repetitive cycle of heat transfer from the heat-generating electronic components to the heat sink.