PATENT DOCUMENT

Publication Number: US-9069535-B2
Application Number: US-201414297576-A
Country: US
Kind Code: B2

Title: Computer thermal system

Abstract:
The present application describes various embodiments regarding systems and methods for providing efficient heat rejection for a lightweight and durable compact computing system having a small form factor. The compact computing system can take the form of a desktop computer. The desktop computer can include a monolithic top case having an integrated support system formed therein, the integrated support system providing structural support that distributes applied loads through the top case preventing warping and bowing. A mixed flow fan is utilized to efficiently pull cooling air through the compact computing system.

Claims:
What is claimed is: 
     
       1. A thermal management system for a desktop computer having a housing, with a longitudinal axis, that encloses an internal volume and that is symmetric about the longitudinal axis, comprising:
 a heat sink disposed within the internal volume and comprising a plurality of planar faces that define and completely enclose a central thermal zone having a polygonal cross section that is perpendicular to the longitudinal axis; and 
 an air mover that moves air through at least the central thermal zone. 
 
     
     
       2. The thermal management system as recited in  claim 1 , further comprising a computational component mounted on at least one of the plurality of planar faces and in thermal contact with the heat sink. 
     
     
       3. The thermal management system as recited in  claim 2 , where the plurality of planar faces and an interior surface of the housing encloses and defines a peripheral thermal zone. 
     
     
       4. The thermal management system as recited in  claim 3 , wherein the plurality of planar faces comprises a first planar face, a second planar face, and a third planar face. 
     
     
       5. The thermal management system as recited in  claim 4 , the heat sink further comprising:
 a center cooling fin that extends from the interior surface of the first planar face to a junction of the interior surface of the second planar face and an interior surface of the third planar face, wherein the center cooling fin bisects the central thermal zone into a first region and a second region each having similar cross sections. 
 
     
     
       6. The thermal management system as recited in  claim 5 , the heat sink further comprising:
 a first cooling fin that extends directly from the interior surface of the first planar face to the interior surface of the second planar face and that spans the first region, and 
 a second cooling fin that extends directly from the interior surface of the first planar face to the interior surface of the third planar face and that spans the second region. 
 
     
     
       7. The thermal management system as recited in  claim 6 , wherein a first angle between the first cooling fin and the interior surface of the first planar face varies in accordance with a distance between the first cooling fin and the center cooling fin. 
     
     
       8. The thermal management system as recited in  claim 7 , wherein a second angle between the interior surface of the second cooling fin and the interior surface of the first planar face varies in accordance with a distance between the second cooling fin and the center cooling fin, wherein a summation of the first angle and the second angle is equal to about 180°. 
     
     
       9. The thermal management system as recited in  claim 8 , wherein the air mover creates a negative pressure differential in a first portion of the internal volume that pulls air into the internal volume at a first opening at a first end of the housing. 
     
     
       10. The thermal management system as recited in  claim 9 , further comprising an air splitter in proximity to the first opening that splits the air pulled into the first opening into a central airflow that is pulled through the central thermal zone and a peripheral airflow that is pulled through the peripheral thermal zone, the central airflow and the peripheral airflow being separate from each other. 
     
     
       11. The thermal management system as recited in  claim 10 , wherein the air mover combines the central airflow and the peripheral airflow into an exhaust airflow. 
     
     
       12. The thermal management system as recited in  claim 11 , wherein the air mover pushes the exhaust airflow out of the internal volume through a second opening opposite the first opening. 
     
     
       13. A thermal management system for removing heat from a desktop computer that includes a housing having a longitudinal axis and that at least partially defines and encloses an internal volume that is symmetric about the longitudinal axis, comprising:
 a heat sink positioned within the internal volume, comprising: 
 a plurality of planar faces that define a central airflow region having a cross section in a shape of a polygon that is perpendicular to the longitudinal axis, at least one of the plurality of planar faces comprising: 
 an interior surface integrally formed with a cooling fin that extends from the interior surface and spans the central airflow region to an interior surface of at least another one of the plurality of planar faces, and 
 an exterior surface configured to carry a computational component in thermal contact with the heat sink. 
 
     
     
       14. The thermal management system as recited in  claim 13 , wherein the plurality of planar faces and an interior surface of the housing enclose and define a peripheral airflow region. 
     
     
       15. The thermal management system as recited in  claim 14 , the housing further comprising a first opening at a first end and second opening at a second end opposite the first end. 
     
     
       16. The thermal management system as recited in  claim 15 , further comprising an air mover near the second opening configured to pull air from an external environment and into the internal volume through the first opening. 
     
     
       17. The thermal management system as recited in  claim 16 , wherein an air splitter near the first opening splits the air pulled through the first opening into a central airflow that is pulled through the central airflow region along a central airflow path that is generally parallel to the longitudinal axis and a peripheral airflow that is pulled through the peripheral airflow region along a peripheral airflow path that is generally parallel to the longitudinal axis and separate from the central airflow path. 
     
     
       18. The thermal management system as recited in  claim 17 , wherein the air mover recombines the central airflow and the peripheral airflow into an exhaust airflow that is pushed out through the second opening and having essentially no tangential components. 
     
     
       19. The thermal management system as recited in  claim 13 , wherein the housing has a cylindrical shape, and wherein the polygon is a triangle. 
     
     
       20. A heat removal system for a computing device enclosed within a cylindrical housing, the heat removal system comprising:
 a plurality of vents configured to receive an intake airflow in accordance with a pressure differential across the plurality of vents and to direct the intake airflow along a longitudinal axis of the cylindrical housing, wherein the plurality of air vents is disposed at a first end of the cylindrical housing; 
 a baffles arrangement disposed between the plurality of vents and the longitudinal axis of the cylindrical housing, the baffles arrangement configured to bifurcate the intake airflow into a central airflow and a peripheral airflow, the central airflow directed towards a central portion of the computing device and the peripheral airflow directed towards a peripheral portion of the computing device; and 
 an air exhaust system disposed at a second end of the cylindrical housing opposite the first end, the air exhaust system configured to receive and combine the central airflow with the peripheral airflow, and to exhaust the combined airflow through an opening in the cylindrical housing at the second end. 
 
     
     
       21. The heat removal system as recited in  claim 20 , the first end of the cylindrical housing comprising a base comprising a pedestal that transitions to a curved portion, and wherein the plurality of vents are disposed along a circumference of the curved portion of the base at an angle with respect to the cylindrical housing that directs the intake airflow towards the longitudinal axis of the cylindrical housing. 
     
     
       22. The heat removal system as recited in  claim 21 , the air exhaust system comprising an air mover disposed proximate the opening in the cylindrical housing. 
     
     
       23. The heat removal system as recited in  claim 22 , wherein the baffles arrangement comprises a data cable electrically coupling a first printed circuit board (PCB) to a second PCB. 
     
     
       24. The heat removal system as recited in  claim 23 , further comprising:
 a heat sink having a triangular cross section that is generally parallel to the longitudinal axis and configured to structurally support a computational component. 
 
     
     
       25. The heat removal system as recited in  claim 24 , wherein the heat sink comprises a cooling fin stack through which the central airflow passes and which carries away at least some of the heat generated by the computational component. 
     
     
       26. A thermal management system for a cylindrical desktop computer having a cylindrical housing that encloses a cylindrical volume having a longitudinal axis, the cylindrical housing having a first opening having a first cross section at a first end and a second opening having a second cross section at a second end opposite the first end, comprising:
 a heat sink disposed within the cylindrical volume and comprising a plurality of planar faces that define and enclose a central thermal zone having a triangular cross section; and 
 an air mover located near the second opening that moves air at least through the central thermal zone. 
 
     
     
       27. The thermal management system as recited in  claim 26 , the heat sink comprising a fin stack that spans the central thermal zone and is generally parallel to the longitudinal axis. 
     
     
       28. The thermal management system as recited in  claim 27 , wherein the air mover pulls an amount of air into the cylindrical housing at the first opening. 
     
     
       29. The thermal management system as recited in  claim 28 , further comprising an air splitter that splits the amount of air pulled into the cylindrical housing into a central airflow that passes through the central thermal zone and a peripheral airflow that passes through a peripheral thermal zone separate from the central thermal zone. 
     
     
       30. The thermal management system as recited in  claim 28 , wherein the fin stack eliminates a radial component from the central airflow as the central airflow passes through the central thermal zone. 
     
     
       31. A method for removing heat generated by a computational component disposed within an air passage enclosed and defined by a cylindrical housing having a longitudinal axis and having a first opening at a first end of the longitudinal axis and a second opening at a second end of the longitudinal axis aligned with and opposite the first end, the method comprising:
 pulling an intake airflow into the air passage through an air intake at the first opening by an air mover located near the second opening; 
 splitting the intake airflow by an air splitter located between the longitudinal axis and the air intake into a central airflow that passes through a central portion of the air passage and a peripheral airflow that concurrently passes through a peripheral portion of the air passage separate from the central portion of the air passage, wherein the computational component transfers at least some heat to the central airflow and the peripheral airflow; 
 combining the central airflow and the peripheral airflow into an exhaust airflow by the air mover; and 
 pushing the exhaust airflow out of the housing through the second opening. 
 
     
     
       32. The method as recited in  claim 31 , wherein the central airflow is pulled through 
       a heat sink positioned within the central portion of the air passage such that the central airflow has essentially no radial components. 
     
     
       33. The method as recited in  claim 31 , wherein the air mover eliminates substantially all tangential components from the exhaust airflow.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of priority under 35 U.S.C §119(e) to: 
     (i) U.S. Provisional Application No. 61/832,698 filed on Jun. 7, 2013 and entitled “COMPUTER ARCHITECTURE RESULTING IN IMPROVED COMPONENT DENSITY AND THERMAL CHARACTERISTICS”; 
     (ii) U.S. Provisional Application No. 61/832,709 filed on Jun. 7, 2013 and entitled “INTERNAL COMPONENT AND EXTERNAL INTERFACE ARRANGEMENT FOR A COMPACT COMPUTING DEVICE”; 
     (iii) U.S. Provisional Application No. 61/832,695 filed Jun. 7, 2013 and entitled “ENCLOSURE/HOUSING FEATURES OF A COMPUTER FOR IMPROVED THERMAL PERFORMANCE AND USER EXPERIENCE”; and 
     (iv) U.S. Provisional Application No. 61/832,633 filed Jun. 7, 2013, entitled “THERMAL PERFORMANCE OF A COMPACT COMPUTING DEVICE”, each of which is incorporated herein by reference in its entirety for all purposes. 
     This application is related to: 
     (i) International Patent Application No. PCT/US2014/041165 filed Jun. 5, 2014 and entitled “COMPUTER SYSTEM”; 
     (ii) International Patent Application No. PCT/US2014/041160 filed Jun. 5, 2014 and entitled “COMPUTER THERMAL SYSTEM”; and 
     (iii) PCT International Patent Application No. PCT/US2014/041153, filed Jun. 5, 2014, entitled “COMPUTER INTERNAL ARCHITECTURE”, 
     each of which is incorporated herein by reference in its entirety for all purposes. 
    
    
     TECHNICAL FIELD 
     The embodiments described herein relate generally to compact computing systems. More particularly, the present embodiments relate to mechanical and thermal structures that contribute to increased thermal efficiency of a compact computing system. 
     BACKGROUND 
     The outward appearance of a compact computing system, including its design and its heft, is important to a user of the compact computing system, as the outward appearance contributes to the overall impression that the user has of the compact computing system. At the same time, the assembly of the compact computing system is also important to the user, as a durable assembly will help extend the overall life of the compact computing system and will increase its value to the user. 
     One design challenge associated with the manufacture of compact computing systems is the rejection of heat from the compact computing system. This design challenge generally arises from a number of conflicting design goals that include the desirability of making the outer enclosure or housing lighter and thinner, of making the enclosure stronger, and of making the enclosure aesthetically pleasing, among other possible goals. Unfortunately, small form-factor housings or enclosures tend to have less surface area across which heat can be dissipated through convection or radiation. Furthermore, even though smaller form-factor housings are desired, decreases in performance are generally deemed unacceptable. 
     SUMMARY 
     The present application describes various embodiments regarding systems and methods for dissipating heat from a lightweight and durable compact computing system having a cylindrical cross section. 
     A compact computing system includes a housing having a longitudinal axis and that encloses and defines an internal volume that is symmetric about the longitudinal axis, a heat sink that encloses at least a central thermal zone having a cross section having a shape of a polygon and that is substantially perpendicular to the longitudinal axis, an air mover configured to direct air through the internal volume and comprising a central airflow through the central thermal zone, and a computing component disposed within the internal volume and supported by and in thermal contact with the heat sink. 
     A desktop computing system includes a housing that at least partially encloses and defines an internal volume that is symmetric about an axis, an air passage within the internal volume that extends along an entire length of the housing, and a computing engine disposed within the air passage and comprising at least one computing component. 
     Other apparatuses, methods, features and advantages of the invention will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the invention, and be protected by the accompanying claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The included drawings are for illustrative purposes and serve only to provide examples of possible structures and arrangements for the disclosed inventive apparatuses and methods for providing compact computing systems. These drawings in no way limit any changes in form and detail that may be made to the invention by one skilled in the art without departing from the spirit and scope of the invention. The embodiments will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements. 
         FIG. 1  shows a perspective view of an embodiment of the compact computing system in a stand-alone and upright configuration. 
         FIG. 2  shows another perspective view of an embodiment of the compact computing system of  FIG. 1  showing an input/output panel. 
         FIG. 3  shows a perspective view of a general system layout of the compact computing system of  FIG. 1  (housing is removed). 
         FIG. 4  shows an exploded view of the compact computing system in accordance with the described embodiments. 
         FIG. 5  shows a partial cross-sectional view of an air inlet of the compact computing system. 
         FIG. 6A  shows a cross-sectional top view of a fin stack of the compact computing system. 
         FIG. 6B  shows a cross-sectional top view of a fin stack of the compact computing system. 
         FIGS. 6C-6D  show cross-sectional top views of compact computing system and airflow regions through which cooling air can pass. 
         FIG. 7A  shows a side view of one of the GPU riser boards and how airflow can be distributed across it. 
         FIG. 7B  shows a side view of the CPU riser board and specifically points out features of the CPU spring. 
         FIG. 8  shows a partial cross-sectional side view of how cooling air is exhausted out of the compact computing system. 
         FIGS. 9A-9B  show fan blade configurations of an impeller in accordance with the described embodiments. 
         FIGS. 10A-10B  show fan blades of an impeller configured with curved stator blades. 
         FIGS. 11A-11B  show a cross-sectional side view and a bottom view of an air exhaust assembly in accordance with the described embodiments. 
         FIG. 12A  shows a rack arrangement suitable for supporting a number of the compact computing systems. 
         FIGS. 12B-12C  shows various other rack arrangements suitable for supporting a number of compact computing systems. 
         FIG. 13  is a block diagram illustrating a method for cooling a compact computing system. 
         FIG. 14  is a flowchart detailing a process in accordance with the described embodiments. 
         FIG. 15  is a block diagram of a representative computing system. 
     
    
    
     DETAILED DESCRIPTION 
     Representative applications of apparatuses and methods according to the presently described embodiments are provided in this section. These examples are being provided solely to add context and aid in the understanding of the described embodiments. It will thus be apparent to one skilled in the art that the presently described embodiments can be practiced without some or all of these specific details. In other instances, well known process steps have not been described in detail in order to avoid unnecessarily obscuring the presently described embodiments. Other applications are possible, such that the following examples should not be taken as limiting. 
     The following relates to a compact computing system that can be configured as a stand-alone unit for placement upon or under a desk or other work area (also referred to as a desktop computer). The compact computing system can also be configured as part of a group of networked or otherwise interconnected computers. In any case, the compact computing system can include a number of electronic components including at least a central processing unit (CPU), and a graphics processing unit (GPU), and other primary and secondary components such a solid state memory devices, wireless components and so on. One or more internal electronic component boards can be shaped to match a surface of the outer enclosure of the compact computing system, including for example, a circular shape to match a top or bottom of a cylinder, or a curved shape to match a segment of an arc conforming to a curved exterior surface of the outer enclosure. In representative embodiments as described herein, the compact computing system can be cylindrical in shape and can be configured to arrange a number of rectangular electronic components as a central core providing a form factor characterized as having a high component packing density (a number of components per available volume). The resulting compact computing device can provide a high computing power density in a small, lightweight, transportable form factor. In some embodiments, the compact computing device can also be coupled to other compact computing devices to form a multi-computer system that can be used as a server computer system (such as in a data farm) or as a network computing system having each compact computing device as a node (or nodes). For example, in the embodiments described herein, the compact computing system can be cylindrical and be configured in such a way that the rectangular electronic components can be assembled as a central core with a form factor having a high component packing density (number of components per available volume). The central core can also have a cylindrical shape in concurrence with a housing having an annular cylindrical shape along the lines of a tube. A thermal management system can respond to changes in an activity level of the central core and can utilize an air mover that can be move copious amounts of air axially through an interior volume defined by the cylindrical housing that can be used to cool the central core in a manner that is both efficient and quiet. Generally speaking, the air mover can provide an airflow of about 15-20 cubic feet per minute (CFM) when major components such as a central processing unit (CPU) and/or a graphics processing unit (GPU) are not being heavily utilized. However, when processing demand increases, the air mover can compensate for any increase in heat generated by ramping up the airflow. For example, in response to an increase in demand for processing resources from either or both the CPU and/or GPU, the air mover can increase the airflow from about 15-20 CFM to about 25-30 CFM (at about room temperature of 25° C.) with an acoustic output of about 35 dbA (it should be noted that these acoustic levels are only experienced when the air mover is performing at a higher end of its operating range during a period of high demand and not during more normal operation). It should be noted that at higher ambient temperature (35° C.), the air mover can ramp the airflow even further to compensate for the reduced thermal transfer at the higher ambient temperature. In this situation, the air mover can ramp the airflow to about 35 to 40 CFM or more having a higher acoustic output of 40 dbA or more. 
     The air mover can occupy a substantial amount of available cross sectional defined by the housing providing an axial airflow substantially free of radial airflow components through a central portion of the housing that includes a central core that includes a heat sink. Moreover, components that make up the central core can be aligned in an axial manner that maximizes an amount of surface area in thermal contact with the axial airflow. Furthermore, the design and layout of the components can also be axial in nature further enhancing the available heat transfer capability and component packing density that leads to higher computing power density (computing operations per available volume). For example, an integrated circuit can be designed to have a power input node (s) at a first end of the integrated circuit and data I/Os at an opposite end of the integrated circuit. 
     The compact computing system can also be coupled to other compact computing systems to form a multi-computer system that can be used as a server computer system (such as in a data farm) or as a network computing system having each compact computing system as a node (or nodes). One advantage of the compact size and shape of the compact computing system is that a simple racking system (along the lines of a wine rack configuration) can be used to position the multiple connected compact computing systems. For example, the individual compact computing systems can be placed at an angle within a rack arrangement in such a way as to provide easy access to inputs as well as outputs for connection to other devices without restricting the flow of air into or out of the compact computing system. In some cases, the individual compact computing systems can be stacked in an alternating arrangement that also does not restrict either air intake or air exhaust. These and other general subjects are set forth in greater detail below. 
     In a particular embodiment, the compact computing system can include a housing that can surround and protect the central core. The housing can be easily removed for servicing or other access. The housing can be formed of aluminum having an aluminum oxide (alumina) layer that both protects the housing and promotes radiative cooling. The aluminum oxide/anodization layer also improved heat rejection from external surface of the housing by increasing its infrared radiative emissivity. Aluminum has a number of characteristics that make it a good choice for the housing. For example, aluminum is a good electrical conductor that can provide good electrical ground and it can be easily machined and has well known metallurgical characteristics. The superior conductivity of aluminum provides a good chassis ground for internal electrical components arranged to fit and operate within the housing. The aluminum housing also provides a good electromagnetic interference (EMI) shield protecting sensitive electronic components from external electromagnetic energy as well as reducing leakage of electromagnetic (EM) energy from the compact computing system. A layer of aluminum oxide can be formed on the surface of the aluminum in a process referred to as anodization. In some cases, the layer of aluminum oxide can be dyed or otherwise imbued with a color(s) to take on a specific color or colors. It should be noted that since aluminum oxide is a good electrical insulator, either the interior surface of the housing is masked during the anodization process to preserve access to the bulk material or selected portions of the layer of aluminum oxide are removed to provide good electrical contacts. 
     In one embodiment, the cylindrical housing can take the form of a single piece housing (monolithic). In this way, the cylindrical housing appears seamless and homogenous. In two dimensions ( 2 D), the cylindrical shape of the housing maximizes a ratio of the volume and enclosure surface area. However, in three dimensions a spherical shape maximizes a ratio of the internal volume and enclosure surface area. In the context of this discussion, the cylinder can be considered more useful; however, a sphere or any other shape for that matter can nonetheless be considered a suitable alternative. In one embodiment, the cylindrical housing is formed of a single billet of a strong and resilient material such as aluminum that is surface treated (anodized) to provide an aesthetically pleasing appearance. A top portion of the cylindrical housing is formed into the lip used to engage a circumferential portion of the airflow that travels in an axial direction from the first opening to the second opening at which point the airflow passes to an external environment. The lip can also be used to transport the compact computing system using for example, a hand. 
     In a particular embodiment, a compact computing system can be assembled using a bottom up type assembly. Initial assembly operations can include installing a vapor chamber on each side of a triangular central core structure. In the described embodiments, the vapor chamber can take on the form of a two phase (vapor/solid) heat spreader. In a particular implementation, the core can take the form of an aluminum frame secured to and cradled within a fixture. High power components, such as a graphic processor unit (GPU) and/or central processor unit (CPU) can be mounted directly to the vapor chambers. 
     A good thermal contact can be formed between the vapor chambers and the high power components using a thermally conductive adhesive, paste, or other suitable mechanism. A main logic board (MLB) can be pressed against a CPU edge connector followed by installation of a GPU flex(es). Once the MLB is seated and connected to the CPU and GPU, memory modules can be installed after which an inlet assembly can be installed and coupled to the core structure using fasteners. An input/output (I/O) assembly that has been independently assembled and pre-tested can be installed after which a power supply unit (PSU) control cable can be connected to the MLB followed by connecting the DC PSU power using a bus bar system. An exhaust assembly can be installed followed by connecting a RF antenna flexes to an I/O board. 
     As noted above, the housing can take on many forms, however, for the remainder of this discussion and without loss of generality, the housing takes on a cylindrical shape that encloses and defines a cylindrical volume. In the described embodiment, the housing and the corresponding cylindrical volume can be defined in terms of a right circular cylinder having a longitudinal axis that can be used to define a height of the right circular cylinder. The housing also can be characterized as having a circular cross section having a center point on the longitudinal axis. The circular cross section can have a radius that extends from the center point and is perpendicular to the longitudinal axis. In one embodiment, a thickness of the housing can be defined in terms of a relationship between an inner radius (extending from the center point to an interior surface of the housing) and an outer radius (extending from the center point to an exterior surface of the housing). The housing can have a thickness tuned to promote circumferential and axial conduction that aids in the spreading out of heat in the housing thereby inhibiting formation of hot spots. The separation between the central core and the housing allows an internal peripheral airflow to cool the housing helping to minimize a touch temperature of the housing. In one embodiment, the housing can be mated to a (releasable) base unit that provides, in part, a pedestal used to support the compact computing system on a surface. The housing can include a first opening having a size and shape in accordance with the base unit. The first opening can be a full perimeter air inlet whose circular design allows for functionality even in those situations where the compact computing system is located in a corner or against a wall. In an assembled configuration, the base unit corresponds to a base of the cylinder. The first opening can be used to accept a flow of air from an external environment passing through vents in the base unit. The amount of air that flows into the housing is related to a pressure differential between the external environment and an interior of the compact computing system created by an air mover assembly near a second opening axially disposed from the first opening. A thermal management system can utilize the air mover that can be move copious amounts of air axially through an interior volume defined by the cylindrical housing that can be used to cool the central core in a manner that is both efficient and quiet. 
     In one embodiment, an air exhaust assembly can take the form of a fan assembly. The fan assembly can be an axial fan assembly configured to axially move air through the housing by creating the abovementioned pressure differential. The fan assembly can also be configured as a mixed air fan assembly providing both axial and centrifugal components to air as it exits the fan assembly. In one embodiment, the fan assembly can occupy a substantial portion of available cross sectional area of the cylindrical housing. For example, the fan assembly can account for at least 85% or thereabouts of an available cross sectional area of an interior of the housing. In any case, air can enter through the vents in the base unit. In one embodiment, a baffle arrangement can bifurcate (split) the airflow in such a way that some of the airflow remains within a central column separate from a peripheral airflow located away from the central column. The central column of air can thermally engage a heat sink structure on which internal components can be mounted. In order to optimize thermal transfer, components can be configured and mounted axially (in the direction of airflow) in order to maximize an amount of air engaging the components. In this way, both the central airflow and the peripheral airflow can be used to cool the central core and still maintain the housing at an acceptable temperature. 
     The housing can include an exhaust lip at the second opening. The exhaust lip can be arranged to engage a portion of the air as it flows out of the second opening having the effect of directing the airflow (and sound) away from the user. The exhaust lip can also provide an integrated handle structure suitable for grasping the compact computing system. The housing can have a thickness that is tuned by which it is meant that the housing has a varying thickness in which a portion of the housing nearest the exhaust lip is thicker than that portion away from the exhaust lip. The thickness of the housing can be varied in a manner that promotes an axial and circumferential conduction of heat in the housing that promotes a more even distribution of heat that inhibits the formation of hot spots in the housing. 
     A good electrical ground (also referred to as a chassis ground) can be used to isolate components that emit significant electromagnetic energy (such as a main logic board, or MLB) from those circuits, such as wireless circuits, that are sensitive to electromagnetic energy. This isolation can be particularly important in the compact computing system due to the close proximity of components that emit electromagnetic energy and those components that are sensitive to electromagnetic energy. Moreover, the housing can include conductive material (such as a gasket infused with conductive particles) that can be mated to a corresponding attachment feature on the base unit completing the formation of a Faraday cage. The Faraday cage can block electromagnetic energy (both internal and external) effectively shielding the external environment from EMI generated by the compact computing system (and the internal environment from externally generated EMI). In order to complete the Faraday cage, air vents in the base unit can be sized to effectively block electromagnetic energy having selected wavelength. More specifically, the wavelength of electromagnetic energy blocked by the vents can be consistent with that emitted by active components with the compact computing system. 
     In one embodiment, the compact computing system can include a sensor configured to detect whether or not the housing is properly in place and aligned with respect to the internal components. Proper placement of the housing is important due to the key role that both the shape and configuration of the housing has with respect to thermal management of the compact computing system as well as completing the Faraday cage discussed above. The compact computing system can include an interlock system that detects the presence and proper alignment of the housing with respect to the internal components. Only when the proper alignment is detected, the interlock system will allow the internal components to power up and operate in a manner consistent with system specification. In one embodiment, the interlock system can include a magnetic element detectable by a Hall effect sensor only when the housing is in a proper position and alignment with respect to the internal components. 
     Due at least to the strong and resilient nature of the material used to form the housing; the housing can include a large opening having a span that does not require additional support structures. Such an opening can be used to provide access to an input/output panel and power supply port. The input/output panel can include, for example, data ports suitable for accommodating data cables configured for connecting external circuits. The opening can also provide access to an audio circuit, video display circuit, power input, etc. In one embodiment, selected data ports can be illuminated to provide easier access in reduced lighting. 
     These and other embodiments are discussed below with reference to  FIGS. 1-15 . However, those skilled in the art will readily appreciate that the detailed description given herein with respect to these figures is for explanatory purposes as the invention extends beyond these limited embodiments. 
       FIG. 1  shows a perspective view of compact computing system  100 . Compact computing system  100  can have a shape defined by housing  102 . In the described embodiments, housing  102  can be cylindrical in shape having a first opening  104  characterized as having diameter d 1 . More specifically, housing  102  can take the form of a circular right cylinder having a longitudinal axis that extends long a centerline of a central volume enclosed by housing  102 . Housing  102  can be characterized as having a circular cross section having a center point coincident with a corresponding point on the longitudinal axis. The circular cross section has a radius that is perpendicular to the longitudinal axis and extends outwardly therefrom. Accordingly, thickness t of housing  102  (more specifically a housing wall) can be defined as a difference between an outer radius r o  associated with an exterior of housing  102  and inner radius r i  associated with an interior surface of housing  102 . Moreover, housing  102  can include second opening  106  axially disposed from first opening  104  having diameter d 2  defined in part by exhaust lip  108  where d 1  is at least equal to or greater than d 2 . Housing  102  can be formed from a single billet of aluminum in the form of a disk that can be extruded in a manner forming exhaust lip  108 . Thickness t of housing  102  can be tuned to mitigate hot spots. In this regard, housing  102  can have a non-uniform thickness t. In particular, portion  110  near exhaust lip  108  can have a first thickness of about 4-6 mm that then changes to a second thickness associated with portion  112  that is reduced from the first thickness and located away from exhaust lip  108 . In this way, portion  110  can act as both an integrated handle used to grasp compact computing system  100  and as a feature that absorbs and conducts thermal energy transferred from a portion of exhaust airflow  114  that engages exhaust lip  108 . Through radiative and conductive heat transfer and by limiting the amount of heat transferred to portion  112 , the formation of local hot spots in housing  102  can be mitigated. Tuning the thickness of housing  102  can be accomplished using, for example, an impact extrusion process using a metal disk that is then machined to the desired thickness profile. The metal disk may be made of aluminum, titanium, and any other metallic material that provides the strength, thermal conductivity, and RF-isolation desired. The extrusion process forms a cylinder that is machined in the exterior portion and in the interior portion to acquire the desired cross sectional profile and also the desired visual appeal from the exterior. 
     Compact computing system  100  can further include base unit  116 . Base unit  116  can be used to provide support for compact computing system  100 . Accordingly, base unit  116  can be formed of strong and resilient material along the lines of metal that can also prevent leakage of electromagnetic (EM) energy from components within compact computing system  100  that radiate EM energy during operation. Base unit  116  can also be formed of non-metallic compounds that can nonetheless be rendered electrically conductive using, for example, electrically conductive particles embedded therein. In order to assure that any electromagnetic energy emitted by components within compact computing system  100  does not leak out, lower conductive gasket  118  can be used to complete a Faraday cage formed by base unit  116  and housing  102 . Upper conductive gasket  120  (shown in more detail in  FIG. 3 ) can be disposed on the interior surface of housing  102  near a lower edge of portion  110 . Use of conductive gaskets  118  and  120  to complete the Faraday cage can increase EMI isolation by about 20 dB. 
     Base unit  116  can also include vents  122 . Vents  122  can be dual purpose in that vents  122  can be arranged in base unit  116  in such a way that a suitable amount of air from an external environment can flow through vents  122  in the form of intake airflow  124 . In one embodiment, intake airflow  124  can be related to a pressure differential across vents  122  created by an air mover disposed with compact computing system  100 . In one embodiment, the air mover can be disposed near second opening  106  creating a suction effect that reduces an ambient pressure within housing  102 . In addition to facilitating intake airflow  124 , vents  122  can be sized to prevent leakage of electromagnetic energy there through. The size of vents  122  can be related to a wavelength corresponding to electromagnetic energy emitted by internal components. 
       FIG. 2  shows another embodiment of compact computing system  100  in the form of compact computing system  200 . It should be noted that compact computing system  200  can be substantially the same or similar as compact computing system  100  with respect to size and shape of housing  102 . Compact computing system  200  can include housing  202  that can differ from housing  102 . In this embodiment, housing  202  can include opening  204  having a size and shape in accordance with interface panel  206 . Interface panel  206  can include various ports used for communication of data between compact computing system  200  and various external circuits. For example, interface panel  206  can include audio jack ports  208  that can be used to provide an audio stream to an external audio circuit, such as a headphone circuit, audio processor, and the like. A set of data ports  210  can be used to transfer data of various forms and/or power between an external circuit(s) and compact computing system  200 . Data ports  210  can be used to accommodate data connections such as USB, Thunderbolt®, and so on. For example, the set of data ports  210  can include data ports  212  in the form of USB ports whereas data ports  214  can take the form of Thunderbolt® ports. In this way, compact computing system  200  can be interconnected to other computing systems such as data storage devices, portable media players, and video equipment, as well as to form a network of computing systems. Furthermore, data ports  216  can take the form of Ethernet ports suitable for forming communication channels to other computing systems and external circuits whereas data port  218  in the form of an HDMI port can be used for audio/video (AV) data transport. In this way, data port  218  can be used to stream high speed video between compact computing system  200  and an external video monitor or other video processing circuitry. Accordingly, interface panel  206  can be used to form connections to a large number and variety of external computing systems and circuits which is particularly useful in those situations where a large amount of computing resources are required without the high capital costs associated with large mainframe type computers. Moreover, the compact size and shape of compact computing system  200  also lends itself to space efficient computing networks, data farms, and the like. 
     Interface panel  206  can be made of a non-conductive material to electrically insulate each of the ports from one another and from housing  202 . Accordingly, interface panel  206  may include a plastic inlay dyed to provide a cosmetic appeal to computing system  200 . For example, in some embodiments interface panel  206  is dyed with a black or dark tint. Below the surface of interface panel  206 , a conductive web supported by a conductive gasket maintains a Faraday cage for RF and EMI insulation formed between housing  202  and upper and lower conductive gaskets ( 118 ,  120 ) located at an interior surface of housing  202 . Power on/off button  220  can be readily available to accept a user touch for initiating a power on sequence (including, for example, boot up process) as well as a power down sequence. Power input port  222  can be sized and shaped to accept a power plug suitable for transferring external power to operational components within housing  202 . In some cases, compact computing system  200  can include internal power resources (such as a battery) that can be charged and re-charged in accordance with power delivered by way of power input port  222 . 
     Housing interlock opening  224  can be accommodate housing interlock  226  used to secure housing  202  to internal structures of compact computing system  200 . Housing interlock  226  can take the form of a sliding latch or other such mechanism that can be manually engaged and disengaged. In this way, housing  202  can be easily removed in order to expose internal components and structures for servicing, for example. It should be noted that although not shown, a detection circuit can be used to detect if housing  202  is properly in place with respect to internal components and structures. This is particularly important since thermal management of compact computing system  200  relies to a large degree on the presence and proper placement of housing  202 . Therefore, it is desired that if it is determined that housing  202  is not in proper placement or alignment with respect to internal structures or components, then the detection circuit will prevent compact computing system  200  from operating, or at least operating at full capacity. In one embodiment, the detection circuit can include a magnetic sensor (such as a Hall Effect device) located to detect a magnet(s) disposed on housing  202  only when housing  202  is properly placed and aligned. 
     Removing housing  202  can expose a central core of compact computing system  200 . More specifically,  FIG. 3  shows central core  300  of compact computing system  200  absent housing  202 . Central core  300  can include a computing engine having computational components and a heat sink that can be used as a framework used to support at least some of the computational components. In this way, the computing engine takes on a form factor in accordance with that of the heat sink. Accordingly, the cylindrical shape of compact computing system  200  dictates the arrangement of various internal components as well as requirements for thermal management. For example, internal components can be arranged in an axial manner that optimizes both a component packing density (the number of operational components per available volume) and a computing power density (computing power per available volume). Moreover, the axial arrangement of internal components also optimizes an amount of heat that can be transferred to intake airflow  124  from the internal components and removed by way of exhaust airflow  114 . (It should be noted that, in general, the nature of compact computing system  200  provides that intake airflow  124  be about the same as that of exhaust airflow  114 .) 
     For example, memory module  302  can be formed of substrate  304  on which is mounted memory device  306 . Substrate  304  can have major axis  310  that is parallel to peripheral airflow  312 . In order to optimize heat transfer from memory device  306  to peripheral airflow  312 , memory device  306  can be mounted onto substrate  304  in a manner that maximizes a thermal transfer interface with peripheral airflow  312 . For example, each memory device can have a shape corresponding to a minor dimension (representing a width W, for example) and a major dimension (represented by a length L, for example). In the embodiment shown, the minor dimension W of memory device  306  is aligned generally parallel to peripheral airflow  312 . In this way, a thermal transfer interface formed between peripheral airflow  312  and memory device  306  disposed on memory module  302  can be optimized. It should also be noted that peripheral airflow  312  is constrained by the presence of housing  202  to flow in a peripheral region defined by an interior surface of housing  202  and central core  300 . Moreover, peripheral airflow  312  can be characterized as having substantially no radial components through the central portion where most heat generating components reside thereby further enhancing the heat transfer capability of peripheral airflow  312  with respect to memory module  302  and memory device  306 . In this way, the axial components of peripheral airflow  312  align with the minor dimension W of memory device  306 . It should be noted that intake airflow  124  is split into peripheral airflow  312  and central airflow  314  (not shown) that flows within a central portion of the central core  300 . Accordingly, peripheral airflow  312  and central airflow  314  are combined forming exhaust airflow  114  prior to passing out of compact computing system  200  through second opening  106 . 
     In the described embodiment, air mover  320  can be disposed in proximity to second opening  106  (cf.  FIG. 1 ). It should be noted that air mover  320  could combine the central airflow  314  and peripheral airflow  312  back into exhaust airflow  114 . Air mover  320  can include air exhaust assembly  322  that can be used to direct exhaust airflow  114  through second opening  106  at least some of which engages with exhaust lip  108  in a manner that facilitates the transfer of thermal energy generated by internal components of compact computing system  200 . Air exhaust assembly  322  includes vents  324  to allow exhaust airflow  114  to pass through. Cosmetic shield  326  can be used to cover operational components such as RF circuits and antenna. In this regard, cosmetic shield  326  can be formed of RF transparent material such as plastic, ceramic, or other non-conductive materials. 
     Due to the electrically conductive nature of housing  202 , housing  202  can be used as a chassis ground to provide a good ground for internal components. Accordingly, touch points  328  can be formed of conductive material and be used to form a conductive path between internal components and an interior of housing  202 . It should be noted that in order to make a good electrical connection, portions of housing  202  contacting touch points  328  are devoid of any non-conductive or insulating material (such as aluminum oxide). Therefore, in those cases where housing  202  has an aluminum oxide layer formed thereon, selected portions of the aluminum oxide are removed (or that portion of housing  102  masked during the anodization operation) to expose bulk material in those locations that come into contact with touch points  328 . As discussed above, in order to prevent leakage of electromagnetic energy, housing  202  and base unit  116  forms a Faraday cage. 
     In order to provide a user-friendly interaction with compact computing system  200 , central core  300  may include sensors such as accelerometers disposed on a plurality of points. Thus, as the user handles housing  202  in order to position compact computing system  200  in a convenient location and orientation, illumination patterns can be used to highlight aspects of interface panel  206  so as to make portions of interface panel  206  more visible to the user. Accordingly, some of the sensors may include light sensing devices to determine whether or not there is sufficient ambient illumination for the user to see selected items on interface panel  206 . 
       FIG. 4  shows a perspective exploded view of compact computing system  100 . Heat sink  402  can include a plurality of planar faces  403  that define a central volume  405  having a triangular cross section along the lines of a triangular prism. Heat sink  402  can also act as a support structure, or a frame, upon which a computing engine that includes at least computational components of compact computing system  100  can be supported. In this way, the computing engine can take on the general shape of heat sink  402 . In one embodiment, heat sink  402  can cooperate with an interior surface of housing  102  to define a peripheral zone that can be used as an air path for peripheral airflow used to cool at least some of the computational and operational components of compact computing system  100 . Central volume  405  can also be used as an air path for a central airflow  314  to further cool at least some of the computational and operational components. In order to facilitate the cooling afforded by central airflow  314 , heat sink  402  a plurality of cooling fins  407  that extend from a first planar face to at least a second planar face and spans the triangular central volume. In one embodiment, a center cooling fin can extend from the first planar face to a junction of the second and a third planar face. In this way, the center cooling fin can separate central volume  405  into two adjacent volumes each having similar triangular cross sections can include vapor chambers  404  that are disposed on each face  403  of heat sink  402 . 
     Vapor chamber  404  can be used to distribute heat generated by various integrated circuits across each planar face of heat sink  402 . CPU riser board  406 , that can include a multi-core central processing unit (CPU) and memory modules  302  can be coupled to heat sink  402  by way of attachment points  408 . Attachment points  408  can cooperate with CPU spring  410  to place the CPU in direct thermal contact with vapor chamber  404 . CPU spring  410  can be utilized to provide a predefined amount of pressure between the CPU and its associated cooling stack and vapor chamber  404 . Similarly, Graphics Processing Unit (GPU) riser board  412  and GPU riser board  414  can be similarly coupled to their respective faces of heat sink  402 . GPU riser boards  412  and  414  each include a GPU  416  surrounded by Video Random Access Memory (VRAM) Chips  418 . In this depiction, four VRAM chips  418  can be arranged in a diamond pattern around GPU  416 . When GPU riser boards  412  and  414  are coupled to their respective vapor chambers  404 , GPU  416  and each of VRAM chips  418  can be in direct thermal contact with a respective vapor chamber  404 . It should be noted that in some configurations (not shown) a single vapor chamber can wrap around an edge of heat sink  402  such that integrated circuits mounted on GPU riser boards  412  and  414  can dissipate heat across vapor chamber having a substantially larger area. Such a configuration can be advantageous in single GPU operations. Furthermore, VRAM chips  418  can include thermal gap pads that put them in direct thermal contact with a vapor chamber  404  as VRAM chips tend to have a lower profile than proximate GPU  416 . In this way, vapor chambers  404  thereby facilitate even spread of heat across each face of heat sink  402  during operation of compact computing system  100 . Also depicted is Solid State Drive (SSD) module  420  which can be coupled to a rear face of GPU riser board  414 . 
     Once each of riser boards  406 ,  412 , and  414  are securely coupled to heat sink  402 , each of the riser boards can be electrically coupled together across main logic board (MLB)  422 . In some embodiments MLB  422  can include a System Management Controller (SMC) chip. CPU riser board  406  includes a card edge connector  424  that attaches to MLB  422  at card edge slot  426 . In one embodiment, card edge connector  424  can be a PCI-E 3.0 type connector allowing at least 32 lanes of PCI-E to run between CPU riser board  406  and MLB  422 . GPU Riser Boards  412  and  414  can be coupled to MLB  422  at flex jumper connectors  428 . In this way, each of riser boards  406 ,  412 , and  414  can be in electrical contact. 
     Compact computing system  100  also includes an input output (I/O) assembly  430 . Input/Output (I/O) assembly  430  encompasses a number of components including power supply unit (PSU)  432 . PSU  432  can supply external power to various components of compact computing system  100 . In one embodiment PSU  432  can be configured to supply about 450 W of total power to compact computing system  100 . PSU  432  can also include airflow perforations  434  that are configured to allow cooling air to flow through PSU  432  during operation of compact computing system  100 . Airflow perforations  434  can be sized to regulate a flow of air through PSU  432 . I/O assembly  430  also includes I/O board  436 . I/O board  436  can be electrically coupled to MLB  422  by a flex jumper cable (not shown) when compact computing system  100  is completely assembled. I/O board  436  allows high-speed communications to enter and leave compact computing system  100 . I/O assembly  430  also includes structural wall  438 , which provides a cosmetic interface for users when installing and removing high-speed data cables or power cables from compact computing system  100 . Once I/O assembly  430  is fully assembled, structural wall  438  can be coupled to a top lip portion of base unit  116 . 
       FIG. 4  also provides a depiction of air exhaust assembly  440 . Air exhaust assembly  440  includes plenum plate  442 , impeller  316 , air exhaust vents  318  and cosmetic shield  326 . Plenum plate  442  can be operable to shape a flow of air into impeller  316 . Plenum plate  442  can also be operable as a shroud for fan blades of impeller  316 , which will be discussed in detail below. Impeller  316  and plenum plate  442  can be coupled to air exhaust vents  318 . Cosmetic shield  326  can be secured to a top surface of air exhaust vents  318 . Once fully assembled air exhaust assembly  440  can be coupled to a top portion of heat sink  402 . In this way central core  300  can be assembled. 
       FIG. 5  shows a partial cross-sectional view of base unit  116  showing vents  122 . As depicted, intake airflow  124  can be drawn into compact computing system  100  through vents  122 . As intake airflow  124  passes through base unit  116 , ribs  502  help to direct airflow entering compact computing system  100 . In some embodiments, ribs  502  can facilitate the transition of intake airflow  124  into peripheral flow  312  and central airflow  314 . In the described embodiment, a first portion of intake airflow  124  can be directed by ribs  502  towards the central volume of heat sink  402  in the form of central airflow  314 . In one embodiment, a baffle arrangement  504 , also referred to as an airflow splitter, can be used to split intake airflow  124  into the central airflow  314  as described above and a second portion into the peripheral airflow  312 . In one embodiment, a flex jumper cable  504  can be used as the airflow splitter. In this way, flex jumper cable  504 , in addition to electrically coupling GPU riser board  414  to MLB  422 , can redirect proportionate amounts of intake airflow  124  into the central airflow  314  and the peripheral airflow  312 . For example, flex jumper cable  504  can bias more of airflow  124  towards a central portion of GPU riser board  414  than over peripheral edges of the board. Widening or narrowing flex jumper cable  504  can adjust an amount of air that is redirected up GPU riser board  414 . It should be noted that a distance between a bottom surface of GPU riser board  414  and MLB  422  can be adjusted to bias more or less air to enter central airflow  314 . 
       FIG. 6A  shows a top cross-sectional view of heat sink  402 . Machining a number of features from an extruded aluminum block can form heat sink  402 . In one embodiment, a plurality of cooling fins  602  can be attached to the interior surfaces of planar faces of heat sink  402  while in another embodiment, plurality of cooling fins  602  can be created as a part of the extrusion process during which the planar faces of heat sink  402  are formed. In either case, plurality of cooling fins  602  can be distributed in a number of ways. In one embodiment, all of plurality of cooling fins  602  can extend from first planar face  604  to at least second planar face  605  spanning triangular central volume  607 . In an embodiment, one of the plurality of cooling fins  602  (referred to as center cooling fin  602 - 1 ) can extend from first planar face  604  to a junction of second planar face  605  and third planar face  609 . In this way, the triangular central volume defined by heat sink  402  is bisected into first region I and second region II each having similar right triangular cross sections. In one embodiment, first cooling fin  602 - 2  spanning region I can be at first angle Ø1 with respect to first planar face  604 . First angle Ø1 can have an angular value that varies in accordance with a distance a 1  between first cooling fin  602 - 2  and central cooling fin  602 - 1 . Similarly, second cooling fin  602 - 3  spanning region II can be at second angle Ø2 with respect to first planar face  604 . Second angle Ø2 can have an angular value that also varies in accordance with a distance a 2  between second cooling fin  602 - 3  and central cooling fin  602 - 1 . Generally speaking, distance a 1  and distance a 2  are about equal, however, the number of cooling fins actually implemented in either regions I or II can vary as required for a particular design as can the various geometric relationships. In one embodiment, a summation of first angle Ø1 and second angle Ø2 can be about 180°. 
     Any of the planar faces can be modified to accommodate various components. For example, a portion of first planar face  604  can be removed by any number of processes to leave a low profile mounting position for vapor chamber  404 . Vapor chamber  404  can be adhesively or mechanically fixed to the first planar face  604 . Vapor chamber  404  can have very efficient heat conduction properties, on the order of about 10 times the heat conduction efficiency of copper. In some embodiments a conductive gel can be placed between vapor chamber  404  and heat sink  402  to facilitate efficient heat transfer between vapor chamber  404  and heat sink  402 . Vapor chamber  404  can also include attachment points  408 . Attachment points  408  can be integrally formed with vapor chamber  404  and are configured to provide a means for attaching the various riser boards associated with compact computing system  100  to the vapor chambers. 
       FIG. 6B  illustrates another cross-sectional view of heat sink  402  with a number of riser boards attached. CPU riser board  406  is shown attached to vapor chamber  404 . CPU riser board  406  attaches to vapor chamber  404  through a low profile thermal module  606 . Low profile thermal module  606  can be configured to properly seat CPU  608  on socket  610  of CPU riser board  406 . In some embodiments low profile thermal module  606  can exert about 100 pounds of force on CPU  608 . This 100 pounds of force can be balanced by CPU spring  410  disposed on the opposite side of CPU riser board  406 . CPU spring  410  can be a U-shaped spring that when flattened counteracts the force of low profile thermal module  606 . CPU spring  410  can be made of any number of robust materials. In one embodiment CPU spring  410  can be made from 17-7 precipitation hardening stainless steel. 
     In addition to seating CPU  608 , low profile thermal module  606  can have apertures through which fasteners  609  (also referred to as fasteners  714  in  FIG. 7B ) can engage attachment points  408  of vapor chamber  404 . The fasteners  611  (also referred to as fasteners  716  in  FIG. 7B ) coupling CPU riser board  406  to vapor chamber  404  can be used to establish a robust thermal interface between CPU  608  and vapor chamber  404 . Fasteners  611  are disposed behind fasteners  609  and are represented as dashed lines in the cross-sectional view of  FIG. 6B . In some embodiments about 30 pounds of force can be applied between CPU  608  and vapor chamber  404 . In addition to seating CPU  608 , CPU spring  410  can also be utilized to help set the 30 pounds of force between CPU  608  and vapor chamber  404 . This applied force allows robust thermal contact to be established between CPU  608  and vapor chamber  404  as well as securely attaching CPU riser board  406  to heat sink  402 . GPU riser boards  412  and  414 , having GPU  614  and GPU  616  respectively, can be mechanically coupled to the other faces of heat sink  402 . Similarly to CPU riser board  406 , GPU riser boards  412  and  414  can be coupled to their respective vapor chambers. For example, GPU riser board  412  can be coupled to its respective vapor chamber by fasteners  618 . 
     Fasteners  618  can couple to attachment points disposed on the vapor chamber, and an amount of pressure between vapor chamber  404  and GPU  614  can be balanced by GPU spring  620 . Fasteners  618  can cooperate with GPU spring  620  to provide a predetermined amount of force to seat GPU riser board  412  to heat sink  402 . In one embodiment, GPU  614  can be soldered to GPU riser board  412  eliminating the need for additional applied pressure in order to seat GPU  614  within a socket. It should also be noted that in some embodiments GPU riser board  412  can include stiffener  622  which can be operable to receive a force from GPU spring  620  and provide additional structural support to GPU riser board  412 . It should also be noted that one (as depicted) or both GPU riser boards  412 ,  414  can include SSD module  420 . SSD module  420  can be coupled to a rear surface of one or both GPU riser boards  412 ,  414 . 
       FIG. 6C  shows yet another cross-sectional view of heat sink  402  disposed within housing  102 . In addition to showing housing  102  surrounding heat sink  402 , I/O assembly  430  is depicted as well. I/O assembly  430  includes PSU  432 , I/O board  436 , and structural wall  438 . I/O assembly  430  includes a number of dotted holes representing perforations in a top surface of PSU  432 . In some embodiments, the perforations of PSU  432  can be sized to adjust a flow of air through PSU  432 . Disposed on an outward facing surface of I/O board  436  is connector column  624 , which represents a column of connectors accessible to a user through I/O inlay  626 . In one embodiment I/O inlay  626  can be a RF transparent hard plastic that is highly resistant to scratching. 
       FIG. 6D  shows the same cross section from  FIG. 6C  divided into airflow regions. Central airflow  314  is depicted in  FIG. 6D  as an airflow path that parallels the longitudinal axis of housing  102  and within the triangular central region of heat sink  402 . As shown in more detail in  FIG. 7A , peripheral airflow  312  can diverge into a plurality airflow branches one of which can be directed along a back portion of the GPU riser boards and shown as GPU airflow regions  630  and  632 . It should be noted that various computational components can have duty cycles that generate copious amounts of thermal waste heat. For example, SSD module  420  can be disposed on only GPU riser board  414 . SSD module  420  can cause substantially more heat to be emitted into GPU airflow region  630  than GPU airflow region  632 , given otherwise similar operating parameters of both GPU riser boards  412 ,  414 . In such a case, balancing operations can be implemented to offload GPU operations from GPU riser board  414  to GPU riser board  412 , thereby balancing heat dissipation across airflow regions  630  and  632 . 
     A portion of peripheral airflow  312  can be directed along both sides of CPU riser board, as depicted by airflow regions  634 . In this way, CPU riser board  406  can receive convective cooling on both front and rear surfaces. Airflow regions  636  represent airflow that applies convective cooling to memory (DIMM) modules  302 . Airflow region  638  represents a portion of peripheral airflow  312  that is routed through PSU  432 . As mentioned above, perforations in a top surface of PSU  432  can be sized to adjust an amount of airflow through PSU  432 . Finally, airflow region  640  can represent a volume of air directed along I/O board  436 . Various airflow guides can be utilized to facilitate establishing an optimal amount of airflow for each airflow regions. For example, in one embodiment ribs  502  can have varying angles depending on their angular position on base unit  116  (that in some embodiments can be releasable), to help distribute the airflow to a desired airflow region. In one embodiment, almost 50% of the air passing through compact computing system  100  can be directed into central airflow  314 . In such a configuration about 10% can be drawn through airflow region  638 , and the remaining approximately 40% of the airflow can be divided across the other airflow regions. 
       FIG. 7A  illustrates a side view of GPU riser board  414 . Airflow over GPU riser board  414  is indicated as peripheral airflow  312 , which as described in relation to  FIG. 5  can be diverted up over GPU riser board  414  by flex jumper cable  504 . This leaves a disproportionately large amount of peripheral airflow going over a central portion of GPU riser board  414 . This can be advantageous in embodiments such as the one depicted where heat emitting bodies such as SSD module  420  and GPU (not shown) are disposed in a central portion of GPU riser board  414 . As peripheral airflow  312  travels up GPU riser board  414  it can naturally spread out along the GPU riser board  414 . In addition to the natural normalization of airflow  312  the spreading of airflow  312  can be further encouraged by an interaction between a top portion of GPU riser board  414  and plenum plate  442 . Because peripheral portions of GPU riser board  414  are disposed at a greater radial distance from a center point of circular plenum plate  442 , a larger gap is left for air to rush over GPU riser board  414  and into impeller  316  (not shown). Consequently, an outer peripheral portion of peripheral airflow  312  can be greater in the upper portion of GPU riser board  414 . The upper portion of GPU riser board  414  can be configured such that heat-emitting components can benefit from the more uniform distribution of airflow  312 . For example, DC inputs  702  can emit a substantial amount of heat. Furthermore, power-conditioning modules  704  can be spread at even intervals across GPU riser board  414 . Capacitors  706  can also greatly benefit from convective cooling provided by peripheral airflow  312 . It should be noted that many of the heating bodies, including for example SSD module  420  and power conditioning modules  704 , as depicted, can be disposed vertically so the airflow over them and resulting convective heat transfer is maximized. It should be noted that peripheral airflow  312  over GPU riser board  412  can be substantially similar to the airflow depicted with regards to GPU riser board  414 . 
       FIG. 7B  illustrates a side view of CPU riser board  406 . This view is provided to show additional detail of CPU spring  410 . CPU spring  410  as previously discussed can be constructed from a U-shaped  17 - 7  precipitation hardened stainless steel alloy. Force can be applied by fasteners along CPU spring  410  to flatten it against a rear side of CPU riser board  406  as depicted. CPU spring  410  can include a number of various sized bands. CPU spring bands  710  as depicted are thicker than CPU spring bands  712  and provide the about 200 pounds of force needed to seat a CPU (not shown) to CPU riser board  406 . Fasteners  714  extend only into low profile thermal module  606 , allowing CPU spring  410  to securely seat a CPU on CPU riser board  406  prior to installing CPU riser board  406  on heat sink  402 . Fasteners  716  are configured to apply about 30 pounds of force through narrower CPU spring bands  712  and additionally operate to couple CPU riser board  406  to attachment points  408  of the vapor chamber configured to receive CPU riser board  406 . It should be noted that stiffener  718  can be disposed between CPU spring  410  and CPU riser board  406  to provide additional structural rigidity to CPU riser board  406 . 
       FIG. 8  illustrates a partial cross sectional side view of air exhaust assembly  440  disposed within a top portion of housing  102 . Central airflow  314  is combined with peripheral airflow  312  at air exhaust assembly  440 . Air exhaust assembly  440  includes impeller  316  that is responsible for drawing air through compact computing system  100  during operation of the device. Impeller  316  receives central airflow  314  and peripheral airflow  312 , and combines them back into exhaust airflow  114 . As depicted, exhaust airflow  114  is exhausted with axial and centrifugal components, consequently impeller  316  can be said to be a mixed flow fan. The axial components of exhaust airflow  114  reduce an amount of pressure drop when exhaust airflow  114  contacts portion  110  of housing  102 , as the flow does not undergo as much redirection as it would if it exited air exhaust assembly  440  in a substantially centrifugal direction. The axial components of exhaust airflow  114  also help to reduce a transfer of heat between exhaust airflow  114  and portion  110  of housing  102 . In this way, a normal operating temperature of portion  110  of housing  102  can be kept at a low enough temperature to allow a user to comfortably maneuver housing  102 . It should be noted that exhaust airflow  114  can be further conditioned to exit air exhaust assembly  440  in a substantially radial direction so that air can be expeditiously moved out of housing  102 . Swirling patterns can develop when exhaust airflow  114  contains non-radial components, causing additional pressure drop and increased convective heat transfer to housing  102 . 
     Heat distribution about housing  102  can be further controlled as a function of a thickness  802  of portion  110  of housing  102 . In one embodiment, thickness  802  can be on the order of about 4-6 mm, allowing heat to be efficiently conducted circumferentially about housing  102 . In this way hot spots can be prevented form forming along housing  102 . As depicted, the thickness  802  of housing  102  can be gradually tapered going down as most heat received by housing  102  is near a top portion. Consequently, the heat can be evenly spread circumferentially at the top allowing the narrower lower portion to simply conduct the heat away from the upper opening in housing  102 . In some embodiments impeller  316  can be configured to pull air through compact computing system  100  at a rate of about 28-29 cubic feet per minute, while keeping the overall acoustic output of compact computing system below 37 dB. 
       FIG. 9A  shows a cross-sectional top view of air exhaust assembly  440 . In this depiction, impeller  316  can have 57 impeller blades  902 . In some embodiments, impeller blades  902  can be disposed about hub  904  at non-uniform intervals. For example, an angular distance between proximate fan blades can vary between about 5.5 and 7 degrees. This irregular spacing can help reduce an acoustic profile of impeller  316 . Table 1 below shows one particular blade spacing configuration that can be utilized with the 57 impeller blades  902  of impeller  316 . Additionally, impeller blades  902  can have backward curved blades to bias exhaust airflow  114  in a radial direction. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 (angular spacing between blades) 
               
            
           
           
               
               
               
            
               
                   
                 Blade # 
                 Angular Spacing (deg) 
               
               
                   
                   
               
            
           
           
               
               
               
            
               
                   
                 1 
                 6.92 
               
               
                   
                 2 
                 6.2399 
               
               
                   
                 3 
                 6.1458 
               
               
                   
                 4 
                 5.7145 
               
               
                   
                 5 
                 5.9564 
               
               
                   
                 6 
                 5.7037 
               
               
                   
                 7 
                 5.7124 
               
               
                   
                 8 
                 5.8201 
               
               
                   
                 9 
                 6.3916 
               
               
                   
                 10 
                 6.1342 
               
               
                   
                 11 
                 6.2996 
               
               
                   
                 12 
                 6.8305 
               
               
                   
                 13 
                 6.3928 
               
               
                   
                 14 
                 6.9324 
               
               
                   
                 15 
                 6.79 
               
               
                   
                 16 
                 6.3158 
               
               
                   
                 17 
                 6.6752 
               
               
                   
                 18 
                 6.332 
               
               
                   
                 19 
                 6.8873 
               
               
                   
                 20 
                 6.9171 
               
               
                   
                 21 
                 6.529 
               
               
                   
                 22 
                 6.8115 
               
               
                   
                 23 
                 6.1026 
               
               
                   
                 24 
                 6.7456 
               
               
                   
                 25 
                 5.7116 
               
               
                   
                 26 
                 5.6961 
               
               
                   
                 27 
                 6.1673 
               
               
                   
                 28 
                 5.8777 
               
               
                   
                 29 
                 5.8416 
               
               
                   
                 30 
                 5.9396 
               
               
                   
                 31 
                 6.1763 
               
               
                   
                 32 
                 6.692 
               
               
                   
                 33 
                 5.8011 
               
               
                   
                 34 
                 6.4961 
               
               
                   
                 35 
                 6.4858 
               
               
                   
                 36 
                 6.305 
               
               
                   
                 37 
                 5.886 
               
               
                   
                 38 
                 5.6992 
               
               
                   
                 39 
                 6.1355 
               
               
                   
                 40 
                 6.9192 
               
               
                   
                 41 
                 6.4834 
               
               
                   
                 42 
                 6.3266 
               
               
                   
                 43 
                 6.395 
               
               
                   
                 44 
                 6.2282 
               
               
                   
                 45 
                 6.4552 
               
               
                   
                 46 
                 6.9279 
               
               
                   
                 47 
                 6.7538 
               
               
                   
                 48 
                 6.9354 
               
               
                   
                 49 
                 6.926 
               
               
                   
                 50 
                 6.4034 
               
               
                   
                 51 
                 6.1482 
               
               
                   
                 52 
                 6.4643 
               
               
                   
                 53 
                 5.7442 
               
               
                   
                 54 
                 5.7055 
               
               
                   
                 55 
                 6.4974 
               
               
                   
                 56 
                 6.2366 
               
               
                   
                 57 
                 6.2388 
               
               
                   
                   
               
            
           
         
       
     
       FIG. 9B  shows a portion of the cross-section shown in  FIG. 9A . Specifically, fan blade  902  can be configured such that a trailing edge of fan blade  902  is inclined about 10 degrees more than a leading edge of fan blade  902 . In one embodiment, as depicted, the leading edge of fan blade  902  can have an angle of 130 degrees, whereas the trailing edge of fan blade  902  can have an angle of about 140 degrees. Even though fan blades  902  are backward swept, as a result of the direction of rotation of impeller  316 , airflow exiting impeller  316  can still have a circumferential component as it exits impeller  316 . Radially oriented 906 can be configured to substantially straighten exhaust airflow  114  as it passes through stators  906  by removing tangential components from airflow  114 . As a result, the direction of mean airflow leaving the stators  906  is more closely aligned to the radial direction. 
       FIGS. 10A-10B  show cross-sectional top views of an alternative embodiment of air exhaust assembly  440 . In this embodiment, stator blades  1002  can have a curved geometry and be oriented in an opposite direction to provide a more gradual redirection of exhaust airflow  114 . This configuration can reduce flow energy lost to turbulence due to separation from stator blade surfaces. In one set of trials a similarly configured curved stator configuration produced about 30% more pressure capacity than a similarly configured system with straight stator blades. In other embodiments straight stator blades can be oriented in a direction similar to depicted curved stator blades  1002 . 
       FIG. 11A  shows a partial cross-sectional side view of air exhaust assembly  440 , including impeller  316 , air exhaust vents  318 , and plenum plate  442 . Impeller  316  can be driven by fan motor  1102 . Fan motor  1102  can be a small form factor motor allowing airflow entrance losses to be reduced as well as allowing more volume for blades  902  should this be desired. In one particular embodiment fan motor  1102  can be a thrust bearing. Due to the compact nature of the thrust bearing, impeller  316  can have a contoured lead-in region  1104  that helps exhaust airflow  114  to have an axial component as it leaves impeller  316 . Air exhaust vents  318 , in addition to including stator blades to make exhaust airflow  114  substantially radial also includes ribs  1106  to add an additional axial component to exhaust airflow  114  as it exits air exhaust assembly  440 . It should be noted that exhaust airflow  114  is shown only on the left side of impeller  316  for exemplary purposes only and would also travel through the right side of impeller  316 . In this embodiment, plenum plate  442  functions as a shroud for impeller  316 . 
       FIG. 11B  shows a bottom view of air exhaust assembly  440  without plenum plate  442 . In this depiction, impeller  316  is shown specifically without a bottom shroud or shroud plate. This configuration can allow impeller  316  to be more easily manufactured in a single piece, versus having to manufacture a distinct shroud plate. Furthermore, such an implementation allows the use of support ring  1108  to dispose at a bottom, peripheral edge of impeller  316 . Support ring  1108  can add structural stability to fan blades  902 . Support ring  1108  can also be used to help balance impeller  316 . For example, a notch or aperture can be designed within support ring  1108  to help remedy a small balance problem that could be associated with impeller  316 . Support ring  1108  can also beneficially provide a small axial component to air that passes over support ring  1108  on its way out of air exhaust assembly  440 . 
       FIG. 12A  shows a rack arrangement  1200  suitable for supporting a number of compact computing systems  100  in accordance with any of the described embodiments. In this depiction, cooling air can be pulled in on one side of rack arrangement  1200  and exhausted on another side. In this way exhaust air from one compact computing system is not likely to be re-circulated into an intake of a nearby computing device. Compact computing systems arranged in such a manner can also be in direct communication via data connectors  1202 . Data connectors  1202  can be embodied by Ethernet cables, Thunderbolt® cables, or any number of other high-speed data transfer protocols. In some embodiments the depicted compact computing systems can be in wireless communication.  FIG. 12B  shows a configuration in which a number of compact computing system are slaved to a master compact computing system, thereby allowing the master compact computing system to allocate resources of the various other compact computing systems.  FIG. 12C  shows various other arrangements compatible with compact computing systems  100 . A perspective view and cross sectional view of one embodiment is depicted showing a hexagonal arrangement of compact computing systems. In another arrangement the compact computing systems can be arranged in a linear, cubic arrangement. 
       FIG. 13  describes a method  1300  for cooling a compact computing system. At step  1302  a flow of cooling air entering the compact computing system is split across a plurality of airflow regions. At step  1304  a portion of the flow of cooling air removes heat from a fin stack in direct thermal contact with a number of printed circuit boards (PCBs). Another portion of the cooling air can be utilized to simultaneously apply convective cooling to a rear portion of each of the number of PCBs. At step  1306 , the flow of cooling air is recombined before being exhausted from the compact computing system. 
       FIG. 14  is a flowchart detailing process  1400  for removing heat from a desktop computer having a cylindrical housing having a first opening at a first end and a second opening axially disposed from the first opening at a second end in accordance with the described embodiments. Process  1400  is carried out by at  1402  creating a negative pressure differential within the cylindrical housing with respect to an external environment near the first opening by an air mover located near the second opening. At  1404 , drawing air into the first opening of the cylindrical housing from the external environment in response to the negative pressure differential as an intake airflow. At  1406 , splitting the intake airflow into a central airflow and a peripheral airflow by an airflow splitter located near the first opening. At  1408 , causing the central airflow to follow a central airflow path through a central volume and the peripheral airflow to follow a peripheral airflow path through a peripheral volume separate from the central volume by the air mover. At  1410 , combining the central airflow and the peripheral airflow into an exhaust airflow at the air mover. At  1412 , creating a positive pressure differential with respect to the external environment near the second opening by the air mover. At  1414 , moving the exhaust airflow out from the cylindrical housing into the external environment in response to the positive pressure differential. 
       FIG. 15  is a block diagram of a computing system  1500  suitable for use with the described embodiments. The computing system  1500  illustrates circuitry of a representative computing system. The computing system  1500  includes input  1501  coupled to processor  1502  that pertains to a microprocessor or controller for controlling the overall operation of the computing system  1500 . It should also be noted that processor  1502  can also refer to multi-processor system. For example, computing system  1500  can include a single or multiple central processing units (CPUs) in addition to a single or multiple dedicated function processors such as a graphics processing unit (GPU). The computing system  1500  stores data (such as media data) in a file system  1504  and a cache  1506 . The file system  1504  typically provides high capacity storage capability for the computing system  1500 . The cache  1506  is, for example, Random-Access Memory (RAM) provided by semiconductor memory. The computing system  1500  can also include a RAM  1508  and a Read-Only Memory (ROM)  1510 . The ROM  1510  can store programs, utilities or processes to be executed in a non-volatile manner. 
     The computing system  1500  also includes a network/bus interface  1514  that couples to a data link  1512 . The data link  1512  allows the computing system  1500  to couple to a host computer or to accessory devices. The data link  1512  can be provided over a wired connection or a wireless connection. In the case of a wireless connection, the network/bus interface  1514  can include a wireless transceiver. The media items (media data) can pertain to one or more different types of media content. In one embodiment, the media items are audio tracks (e.g., songs, audio books, and podcasts). In another embodiment, the media items are images (e.g., photos). However, in other embodiments, the media items can be any combination of audio, graphical or visual content. Sensor  1516  can take the form of circuitry for detecting any number of stimuli. For example, sensor  1516  can include a Hall Effect sensor responsive to external magnetic field, an audio sensor, a light sensor such as a photometer, and so on. 
     Various embodiments are described herein. These embodiments include at least the following. 
     A thermal management system for a desktop computer having a housing with a longitudinal axis that encloses an internal volume that is symmetric about the longitudinal axis is described that includes at least a heat sink disposed within the internal volume that includes a plurality of planar faces that define and at least partially enclose a central thermal zone having a cross section that is perpendicular to the longitudinal axis. The thermal management system also includes an air mover that moves air through at least the central thermal zone. 
     A thermal management system for removing heat from a desktop computer that includes a housing having a longitudinal axis and that at least partially defines and encloses an internal volume that is symmetric about the longitudinal axis includes a heat sink positioned within the internal volume. The heat sink includes a plurality of planar faces that define a central airflow region having a cross section in the shape of a polygon that is perpendicular to the longitudinal axis. At least one of the plurality of planar faces includes an interior surface integrally formed with a cooling fin that extends from the interior surface and spans the central airflow region to an interior surface of at least another one of the plurality of planar faces, and an exterior surface configured to carry a computational component in thermal contact with the heat sink. 
     A heat removal system for a computing device enclosed within a cylindrical housing is described. The heat removal system includes a plurality of vents configured to receive an intake airflow in accordance with a pressure differential across the plurality of vents and to direct the intake airflow along a longitudinal axis of the cylindrical housing where the plurality of air vents is disposed at a first end of the cylindrical housing. The heat removal system also includes a baffles arrangement disposed between the plurality of vents and the longitudinal axis of the cylindrical housing, the baffles arrangement configured to bifurcate the intake airflow into a central airflow and a peripheral airflow, the central airflow directed towards a central portion of the computing device and the peripheral airflow directed towards a peripheral portion of the computing device, and an air exhaust system disposed at a second end of the cylindrical housing opposite the first end, the air exhaust system configured to receive and combine the central airflow with the peripheral airflow, and to exhaust the combined airflow through an opening in the cylindrical housing at the second end. 
     A method for removing heat generated by a computational component disposed within an air passage enclosed and defined by a housing having a first opening at a first end and a second opening at a second end opposite the first end is carried out by drawing an intake airflow into the air passage at the first opening by an air mover located near the second opening, splitting the intake airflow into a central airflow that passes through a central portion of the air passage and a peripheral airflow that concurrently passes through a peripheral portion of the air passage separate from the central portion of the air passage, where the computational component transfers at least some heat to the central airflow and the peripheral airflow, combining the central airflow and the peripheral airflow into an exhaust airflow by the air mover, and removing the heat from the housing by causing the exhaust airflow to move out of the housing through the second opening. 
     A thermal management system for a cylindrical desktop computer includes at least an air exhaust assembly suitable for cooling the cylindrical desktop computer. The air exhaust assembly includes an impeller that includes a hub, a plurality of fan blades protruding radially from the hub, adjacent ones of the plurality of fan blades disposed about the hub at an irregular angular interval, and a support ring integrally formed along a bottom surface of a trailing edge portion of each of the plurality of fan blades, the support ring operative to provide at least structural support to the plurality of fan blades. The thermal management system also includes a plurality of stator blades configured to inhibit formation of radial components in the exhausted airflow. 
     A thermal management system for use in a desktop computer includes an impeller comprising a plurality of fan blades and an air exhaust grill surrounding the impeller and comprising a plurality of air vents through which an exhaust airflow moves out of the desktop computer. The plurality of air exhaust vents includes a plurality of ribs configured to cooperate with the plurality of fan blades to increase an axial component of the exhaust airflow, and a plurality of stators configured to remove a tangential component of the air passing through the air exhaust grill. 
     A heat sink for removing heat from a desktop computer that includes a housing having a longitudinal axis and that at least partially defines an internal volume that is symmetric about the longitudinal axis and a computing engine positioned within the internal volume having a computational component includes a plurality of planar faces that defines a central thermal zone having a cross section that is substantially perpendicular to the longitudinal axis. 
     A compact computing system includes a housing having a longitudinal axis and that encloses and defines an internal volume that is symmetric about the longitudinal axis, a heat sink that encloses at least a central thermal zone having a cross section having a shape of a polygon and that is substantially perpendicular to the longitudinal axis, an air mover configured to direct air through the internal volume and comprising a central airflow through the central thermal zone, and a computing component disposed within the internal volume and supported by and in thermal contact with the heat sink. 
     A consolidated thermal module (CTM) used to secure an integrated circuit (IC) to an electrical connector disposed on a first surface of a printed circuit board (PCB) and to maintain the IC in thermal contact with a heat transfer assembly includes a stiffener plate disposed on a second surface of the PCB, a retaining mechanism at least a portion of which is disposed on the stiffener plate configured to provide a first retaining force and a second retaining force, a first fastener used to secure the IC to the stiffener plate and the retaining mechanism, wherein the retaining mechanism evenly distributes the first retaining force across the stiffener plate that maintains the IC in uniform electrical contact with electrical contacts within the electrical connector, and a second fastener used to secure heat removal assembly to the retaining mechanism that maintains the IC in uniform thermal contact with the heat transfer assembly. 
     A thermal management system for a cylindrical desktop computer having a cylindrical housing that encloses a cylindrical volume having a longitudinal axis, the cylindrical housing having a first opening having a first cross section at a first end and a second opening having a second cross section at a second end opposite the first end includes a heat sink disposed within the cylindrical volume and comprising a plurality of planar faces that define and enclose a central thermal zone having a triangular cross section, and an air mover located near the second opening that moves air having no radial components at least through the central thermal zone. 
     A thermal module (TM) used to secure an integrated circuit (IC) to an electrical connector disposed on a first surface of a printed circuit board (PCB) and to maintain the IC in thermal contact with a heat transfer assembly includes a retaining mechanism configured to provide a first retaining force and a second retaining force, a first fastener used to secure the IC to the retaining mechanism, wherein the retaining mechanism evenly distributes the first retaining force across the IC that maintains the IC in uniform electrical contact with electrical contacts within the electrical connector, and a second fastener used to secure heat removal assembly to the retaining mechanism and that maintains the IC in uniform thermal contact with the heat transfer assembly. 
     A desktop computing system includes a housing that at least partially encloses and defines an internal volume that is symmetric about an axis, an air passage within the internal volume that extends along an entire length of the housing, and a computing engine disposed within the air passage and comprising at least one computing component. 
     Moreover, a thermal management system for a cylindrical desktop computer having a cylindrical housing that encloses a cylindrical volume having a longitudinal axis, the cylindrical housing having a first opening at a first end and a second opening at a second end opposite the first end. The thermal management system includes a heat sink disposed within the cylindrical volume and having a plurality of planar faces that define and enclose a central thermal zone having a triangular cross section. 
     The thermal management system includes cooling fin that extends from an interior surface of a first planar face to at least an interior surface of a second planar face and spans the central thermal zone. In an embodiment, the plurality of planar faces and an interior surface of the cylindrical housing enclose and define a peripheral thermal zone. In an embodiment, a center cooling fin extends from the interior surface of the first planar face to a junction of the interior surface of the second planar face and an interior surface of a third planar face. In an embodiment, the center cooling fin bisects the central thermal zone into a first region and a second region each having similar triangular cross sections. In an embodiment, the system also includes a first cooling fin that extends from the interior surface of the first planar face to only the interior surface of the second planar face and spans the first region. In an embodiment, the system also includes a second cooling fin that extends from the interior surface of the first planar face to only the interior surface of the third planar face and spans the second region. 
     In an embodiment, a first angle between the first cooling fin and the interior surface of first planar face varies in accordance with a distance between the first cooling fin and the center cooling fin. In an embodiment, a second angle between the interior surface of the second cooling fin and the interior surface of the first planar face varies in accordance with a distance between the second cooling fin and the center cooling fin. In an embodiment, a summation of the first angle and the second angle is equal to about 180°. In an embodiment, the heat sink is formed from a single piece of extruded metal. In an embodiment, the system also includes an air mover located near the second opening that creates a negative pressure differential in a first portion of the cylindrical housing that causes air to be drawn into the cylindrical housing at the first opening. In an embodiment, air is split into a central airflow that passes through the central thermal zone and a peripheral airflow that passes through the peripheral thermal zone. In an embodiment, the air mover is configured to recombine the central airflow and the peripheral airflow into an exhaust airflow. 
     In an embodiment, the air mover is configured to create a positive pressure differential in a second portion of the cylindrical housing that forces the exhaust airflow out of the cylindrical housing through the second opening. In an embodiment, one of the planar faces carries the computing component that is maintained within a range of predetermined operating temperatures by the thermal management system. 
     A thermal management system for removing heat from a computing engine having a computational component positioned within a cylindrical housing having a longitudinal housing is described. The thermal management system includes a heat sink having a plurality of planar faces defining a substantially triangular central airflow region. Each of the plurality of faces has an interior surface integrally formed with a plurality of cooling fins that extend from the interior surface and span the triangular central airflow region to an interior surface of another one of the plurality of faces, and an exterior surface configured to carry the computational component in thermal contact with the heat sink. 
     In an embodiment, the plurality of planar faces and an interior surface of the cylindrical housing enclose and define a peripheral airflow region. In an embodiment, the cylindrical housing further including a first opening at a first end and second opening at a second end opposite the first end. In an embodiment, the thermal management system further includes an air mover near the second opening configured to create a negative pressure differential within the cylindrical housing with respect to an external environment at the first opening. In an embodiment, the negative pressure differential at the first opening causes an intake of air into the first opening from the external environment. In an embodiment, the system also includes an air splitter near the first opening configured to split the intake air into a central airflow and a peripheral airflow. In an embodiment, the central airflow moves through the central airflow region along a central airflow path that is generally parallel to the longitudinal axis. 
     In an embodiment, the peripheral airflow moves through the peripheral airflow region along a peripheral airflow path that is generally parallel to the longitudinal axis. In an embodiment, where peripheral and central airflow have essentially no radial components. More specifically, the central airflow has no radial components as it passes through the central airflow region and the peripheral air flow has no radial components as it moves along the peripheral airflow path in that portion in which most of the heat generating components reside. In an embodiment, the air mover is configured to recombine the central airflow and the peripheral airflow into an exhaust airflow. In an embodiment, the air mover is configured to create a positive pressure differential within the cylindrical housing with respect to the external environment near the second opening. In an embodiment, the positive pressure differential forces the exhaust airflow through the second opening and out of the cylindrical housing where the exhaust airflow has a maximum acoustic signature of about 40 dBA and a maximum exhaust airflow at room temperature (25° C.) is about 25-30 cubic feet per minute (CFM) and about 40 CFM at an elevated temperature (35° C.). 
     In an embodiment, a first amount of heat from the computational component is transferred a vapor chamber in thermal contact with one of the plurality of cooling fins that is subsequently transferred to the central airflow. In an embodiment, a second amount of heat from the computational component is transferred directly to the peripheral airflow. In an embodiment, the opening in the second end of the cylindrical housing has an area greater than 50% of an overall cross-sectional area of the second end of the cylindrical housing. In an embodiment, the air mover is a mixed flow fan that produces essentially no radial airflow components. 
     A heat removal system for a computing device enclosed within a cylindrical housing is described. The heat removal system includes a plurality of vents configured to receive an intake airflow in accordance with a pressure differential across the plurality of vents and to direct the intake airflow towards a longitudinal axis of the cylindrical housing where the plurality of air vents is disposed at a first end of the cylindrical housing, a baffles arrangement disposed between the plurality of vents and the longitudinal axis of the cylindrical housing, the baffles arrangement configured to bifurcate the intake airflow into a central airflow and a peripheral airflow, the central airflow directed towards a central portion of the computing device and the peripheral airflow directed towards a peripheral portion of the computing device, and an air exhaust system disposed at a second end of the cylindrical housing opposite the first end, the air exhaust system configured to receive and combine the central airflow with the peripheral airflow, and to exhaust the combined airflow through an opening in the cylindrical housing. In one embodiment, the first end of the cylindrical housing includes a horizontal base that transitions to a curved portion, and where the plurality of vents are disposed along the curved portion of the cylindrical housing at an angle with respect to the horizontal base that directs the intake airflow towards the longitudinal axis of the cylindrical housing. 
     In one embodiment, an air mover disposed proximate the opening in the cylindrical housing defined by a circular lip portion having a tuned thickness arranged to evenly spread heat across the cylindrical housing. In one embodiment, the air exhaust system comprises a mixed flow fan configured to exhaust air out of the cylindrical housing. In one embodiment, the baffles arrangement comprises a data cable electrically coupling a first printed circuit board (PCB) to a second PCB. In one embodiment, a portion of the intake airflow that contacts the data cable is diverted towards the peripheral airflow. In one embodiment, a heat sink is configured to support at least two printed circuit boards, where an interior surface of the cylindrical housing cooperates with an outside surface of the heat sink to define a portion of the peripheral airflow. In one embodiment, the heat sink comprises a cooling fin stack that defines the central airflow. In one embodiment, the opening in the second end of the cylindrical housing has an area greater than 50% of an overall cross-sectional area of the second end of the cylindrical housing. 
     A method for removing heat from a desktop computer having a cylindrical housing having a first opening at a first end and a second opening axially disposed from the first opening at a second end is described. The method is carried out by drawing an intake airflow into the first opening of the cylindrical housing from the external environment by an air mover located near the second opening, where an airflow splitter near the first opening splits the airflow into a central airflow that follows a central airflow path through a central volume and a peripheral airflow that follows a peripheral airflow path through a peripheral volume separate from the central volume and combining the central airflow and the peripheral airflow into an exhaust airflow by the air mover that subsequently moves the exhaust airflow out from the cylindrical housing through the second opening and into the external environment. 
     A thermal management system for a cylindrical desktop computer is described. The thermal management system includes an air exhaust assembly suitable for cooling the cylindrical desktop computer, the air exhaust assembly has an impeller with a hub, a plurality of fan blades protruding radially from the hub, adjacent ones of the plurality of fan blades disposed about the hub at an irregular angular interval, and a support ring integrally formed along a bottom surface of a trailing edge portion of each of the plurality of fan blades, the support ring operative to provide at least structural support to the plurality of fan blades. 
     Also included is a plurality of stator blades and the impeller further includes a shaft axially stabilized by a thrust bearing. In one embodiment, the plurality of fan blades comprises backward swept fan blades. In one embodiment, a trailing edge of each of the plurality of fan blades is inclined about 10 degrees more than a corresponding leading edge of each of the plurality of fan blades. In one embodiment, the plurality of stator blades are curved stator blades, oriented in a direction opposite the plurality of fan blades. In one embodiment, air exhausted from the impeller has both axial and centrifugal components. In one embodiment, a geometry of the hub has a contoured geometry configured to contribute to an axial exhaust component of the airflow. In one embodiment, a plenum plate configured to direct air into the impeller. In one embodiment, the plurality of fan blades comprises 57 fan blades. In one embodiment, each fan blade is separated from an adjacent fan blade by a particular angular interval, where when each of the angular intervals is added together the angular intervals add up to 360 degrees, and where a first angular interval is 6.92°, a second angular interval is 6.2399°, a third angular interval is 6.1458°, a fourth angular interval is 5.7145°, a fifth angular interval is 5.9564°, a sixth angular interval is 5.7037°, a seventh angular interval is 5.7124°, an eighth angular interval is 5.8201°, a ninth angular interval 6.3916°, a tenth angular interval is 6.1342°, an eleventh angular interval is 6.2996°, a twelfth angular interval is 6.8305°, a thirteenth angular interval is 6.3928°, a fourteenth angular interval is 6.9324°, a fifteenth angular interval is 6.79°, a sixteenth angular interval is 6.3158°, a seventeenth angular interval is 6.6752°, an eighteenth angular interval is 6.332°, a nineteenth angular interval is 6.8873°, a twentieth angular interval is 6.9171°, a twenty-first angular interval is 6.529°, a twenty-second angular interval is 6.8115°, a twenty-third angular interval is 6.1026°, a twenty-fourth angular interval is 6.7456°; a twenty-fifth angular interval is 5.7116°, a twenty-sixth angular interval is 5.6961°, a twenty-seventh angular interval is 6.1673°; a twenty-eighth angular interval is 5.8777°; a twenty-ninth angular interval is 5.8416°, a thirtieth angular interval is 5.9396°, a thirty-first angular interval is 6.1763°, a thirty-second angular interval is 6.692°, a thirty-third angular interval is 5.8011°, a thirty-fourth angular interval is 6.4961°, a thirty-fifth angular interval is 6.4858°, a thirty-sixth angular interval is 6.305°, a thirty-seventh angular interval is 5.886°, a thirty-eight angular interval is 5.6992°, a thirty-ninth angular interval is 6.1355°, a fortieth angular interval is 6.9192°, a forty-first angular interval is 6.4834°, a forty-second angular interval is 6.3266°, a forty-third angular interval is 6.395°, a forty-fourth angular interval is 6.2282°, a forty-fifth angular interval is 6.4552°, a forty-sixth angular interval is 6.9279°, a forty-seventh angular interval is 6.7538°, a forty-eighth angular interval is 6.9354°, a forty-ninth angular interval is 6.926°, a fiftieth angular interval is 6.4034°, a fifty-first angular interval is 6.1482°, a fifty-second angular interval is 6.4643°, a fifty-third angular interval is 5.7442°, a fifty-fourth angular interval is 5.7055°, a fifty-fifth angular interval is 6.4974°, a fifty-sixth angular interval is 6.2366°, and a fifty-seventh angular interval is 6.2388°. 
     A thermal management system for use in a cylindrical desktop computer is described. The thermal management system includes a flow fan an impeller includes a plurality of fan blades configured to exhaust air having both axial and centrifugal components and an air exhaust grill surrounding the impeller and defining a plurality of air vents through which the exhaust air exits the mixed flow fan. In the described embodiment, the plurality of air exhaust vents includes a plurality of ribs configured to cooperate with the plurality of fan blades to impart an increased axial component to the air exhausted from the impeller, and a plurality of stators configured to straighten the air exiting the impeller by substantially removing a tangential component of the air passing through the air exhaust grill. 
     In one embodiment, each stator of the plurality of stators has a curved geometry configured to gradually remove the tangential component from the exhaust air such that turbulent flow is substantially avoided. In one embodiment, a curvature of the plurality of fan blades is opposite a curvature of the plurality of stators. In one embodiment, a plenum plate disposed across an inlet portion of the impeller, the plenum plate configured to both direct air into a central portion of the impeller and to function as a shroud to direct air passing through a lower portion of the impeller towards the air exhaust grill. In one embodiment, the impeller further comprises a band coupled to a peripheral portion of the impeller, the band configured to provide structural support to the plurality of blades and to add an additional axial component to a portion of the air it comes in contact with. 
     In one embodiment, a thrust bearing is configured to stabilize the impeller. In one embodiment, the impeller further includes a contoured portion configured to impart an axial component to the air prior to the air being engaged by the fan blades. 
     A heat sink for removing heat from a computing engine that includes a computing component disposed within a cylindrical volume having a longitudinal axis. The heat sink includes at least a plurality of planar faces that enclose and define a central thermal zone having a triangular cross section that is substantially parallel to the longitudinal axis. In one embodiment, one of the planar faces carries the computing component. In one embodiment, the computing engine has a form factor corresponding to the heat sink. In one embodiment, the heat sink comprises a cooling fin that extends along an inside surface of a first planar face. In one embodiment, the cooling fin extends from the inside surface of the first planar face to at least an inside surface of a second planar face and spans the central thermal zone. 
     In one embodiment, a center cooling fin extends from the inside surface of the first planar face to a junction of the inside surface of the second planar face and an inside surface of a third planar face. In one embodiment, the center cooling fin bisects the central thermal zone into a first region and a second region each having similar triangular cross sections. In one embodiment, a first cooling fin that extends from the inside surface of the first planar face to the inside surface of the second planar face and spans the first region. In one embodiment, a second cooling fin that extends from the inside surface of the first planar face to the inside surface of the third planar face and spans the second region. In one embodiment, a first angle between the first cooling fin and the inside surface of first planar face varies in accordance with a distance between the first cooling fin and the center cooling fin. In one embodiment, a second angle between the inside surface of the second cooling fin and the inside surface of the first planar face varies in accordance with a distance between the second cooling fin and the center cooling fin. In one embodiment, a summation of the first angle and the second angle is equal to about 180°. 
     A compact computing system includes a cylindrical housing that encloses and defines a cylindrical volume having a longitudinal axis, a heat sink that encloses at least a central thermal zone that is substantially parallel to the longitudinal axis and a computing component disposed within the cylindrical volume and supported by and in thermal contact with the heat sink. In one embodiment, the cylindrical housing comprises a first opening at a first end of the cylindrical housing having a first diameter corresponding to a diameter of the cylindrical housing and a top opening at a second end opposite the first end having a second diameter. The system also includes a base unit at the first end of the cylindrical housing that fits the first opening of the cylindrical housing and includes a support element that provides support for the compact computing system and a vent that enables passage of the intake airflow in cooperation with the air mover where the air mover is near the top opening. In an embodiment, the air mover merges the central airflow and the peripheral airflow and the air mover moves the merged airflow through the top opening and out of the cylindrical housing. In an embodiment, the second diameter is less than the first diameter. 
     A desktop computing system includes a housing having an axisymmetric shape and a length and an air passage that extends the length of the housing. In one embodiment, a computing engine is disposed within air passage. In one embodiment, a structural core is positioned within the housing that provides structural support for the computing engine such that the computing engine takes on a general shape of the structural core. In one embodiment, the structural core includes a heat sink that facilitates removal of heat from the computing engine. In one embodiment, the heat sink passes the at least some of the heat removed from the computing engine to the air passage. In one embodiment, the housing is a cylindrical housing. In one embodiment, the air passage is a cylindrical air passage. In one embodiment, the structural core has a triangular shape. In one embodiment, the desktop computing system includes an air mover configured to move air through the length of the air passage. 
     The various aspects, embodiments, implementations or features of the described embodiments can be used separately or in any combination. Various aspects of the described embodiments can be implemented by software, hardware or a combination of hardware and software. The described embodiments can also be embodied as computer readable code on a computer readable medium for controlling manufacturing operations or as computer readable code on a computer readable medium for controlling a manufacturing line. The computer readable medium is any data storage device that can store data that can thereafter be read by a computer system. Examples of the computer readable medium include read-only memory, random-access memory, CD-ROMs, DVDs, magnetic tape, optical data storage devices, and carrier waves. The computer readable medium can also be distributed over network-coupled computer systems so that the computer readable code is stored and executed in a distributed fashion. 
     The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the invention. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the invention. Thus, the foregoing descriptions of specific embodiments of the present invention are presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed. It will be apparent to one of ordinary skill in the art that many modifications and variations are possible in view of the above teachings. 
     The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents. 
     While the embodiments have been described in terms of several particular embodiments, there are alterations, permutations, and equivalents, which fall within the scope of these general concepts. It should also be noted that there are many alternative ways of implementing the methods and apparatuses of the present embodiments. It is therefore intended that the following appended claims be interpreted as including all such alterations, permutations, and equivalents as fall within the true spirit and scope of the described embodiments.

Metadata:
Filing Date: 20140605
Publication Date: 20150630
Grant Date: 20150630
Priority Date: 20130607
Inventors: DEGNER BRETT W.
PRATHER ERIC R.
NARAJOWSKI DAVID H.
LIANG FRANK F.
NIGEN JAY S.
DYBENKO JESSE T.
DUKE CONNOR R.
WHANG EUGENE A.
STRINGER CHRISTOPHER J.
BANKO JOSHUA D.
KALINOWSKI CAITLIN ELIZABETH
BERK JONATHAN L.
CASEBOLT MATTHEW P.
FETTERMAN KEVIN S.
WEIRSHAUSER ERIC J.
Assignee: APPLE INC
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Family ID: 52004898