Abstract:
An electrical component having a hybrid air cooling system. The electrical component comprises an air plenum that extends across the width of the component and a first set of air movers that is positionable in a first lateral position downstream of the air plenum within the component enclosure and a second set of air movers that is positionable in a second lateral position downstream of the air plenum within the component enclosure. The first and second sets of air movers each include at least two air movers arranged adjacent each other in series. When both positioned in the component enclosure, the first and second sets of air movers are arranged in parallel such that both serial and parallel air flows are provided within the component enclosure to dissipate heat generated therein.

Description:
FIELD OF THE INVENTION 
     The invention relates generally to an electrical component having a hybrid air cooling system and method. More particularly, the invention relates to an electrical component using redundant serial and parallel air flows to dissipate heat generated within the electrical component. 
     BACKGROUND OF THE INVENTION 
     Data storage components typically comprise a plurality of data storage devices, such as disk drives, that mount within a component enclosure. The data storage devices operate at high speeds, generating relatively large amounts of heat that must be dissipated to ensure proper functioning of the devices. Recently, sufficient heat dissipation in such systems has become increasing difficult to achieve due to the current trend toward increased packing density of the data storage devices within the component enclosures. Extremely high packing density increases the amount of heat generated within the system and similarly increases the difficulty of tailoring effective cooling systems to remove this heat. 
     Conventional data storage systems typically use forced air convection to remove heat generated by the data storage devices within the system. Normally, each data storage component includes a plurality of air movers, such as fans, which draw ambient air over the data storage devices contained within the enclosure and expel the heated air from the component to the ambient air. The air movers are usually arranged in parallel along the rear of the component enclosure such that, if one of the air movers were to fail, one or more other air movers still operate to remove heat generated within the component. When an air mover fails in such systems, however, flow through the adjacent exhaust outlet can reverse due to the influence of the other, still functioning, air movers within the component. In that this reverse air flow can interfere with the airflow within the component enclosure to significantly inhibit the heat dissipation capacity of the cooling system, conventional components often are provided with flapper doors which automatically close when an adjacent air mover fails, to prohibit the flow of air through the exhaust outlet and back into the component enclosure. 
     Although typically providing enough cooling to the data storage devices when each of the air movers is operating correctly, conventional cooling systems of the type described above do not adequately dissipate heat from the data storage devices when one or more of the air movers fails. In particular, when an air mover fails and its adjacent flapper door closes, air flow within the component in the vicinity of the closed flapper door is greatly reduced, resulting in a concomitant reduction in heat dissipation from the data storage devices in that portion of the component. If the nonfunctioning air mover is not replaced quickly, one or more of the storage devices could overheat, resulting in lost information and even permanent damage to the device. Even when air mover failure is quickly detected, replacement normally requires shut-down of the entire data storage component in that the air movers are not placed in a convenient position for online replacement. 
     From the above, it can be appreciated that it would be desirable to have an electrical component that includes a cooling system which solves the above-identified problems. 
     SUMMARY OF THE INVENTION 
     Briefly described, the present invention relates to an electrical component having a hybrid air cooling system. The electrical component comprises a component enclosure including front and rear ends and an air plenum that extends across the width of the component enclosure between the front and rear ends. The component further comprises a first set of air movers positioned in a first lateral position downstream of the air plenum within the component enclosure and a second set of air movers positioned in a second lateral position downstream of the air plenum within the component enclosure such that the first and second sets of air movers are arranged in parallel with each other within the component enclosure. The first and second sets of air movers each typically comprise at least two air movers arranged directly adjacent each other in series. Arranged in this manner, the first and second sets of air movers provide both serial and parallel air flows within the component enclosure to dissipate heat generated therein. 
     In addition, the invention relates to a method of dissipating heat generated within an electrical component that has a component enclosure including front and rear ends and an air plenum that extends across the width of the component enclosure between the front and rear ends. The method comprises the steps of providing a first set of air movers arranged adjacent each other in series in a first lateral position downstream of the air plenum within the component enclosure and providing a second set of air movers arranged adjacent each other in series in a second lateral position downstream of the air plenum within the component enclosure, wherein the first set of air movers is arranged in parallel with the second set of air movers within the component enclosure such that both serial and parallel air flow is provided within the component enclosure to dissipate heat generated therein. 
    
    
     The particular objects, features, and advantages of this invention will become more apparent upon reading the following specification, when taken in conjunction with the accompanying drawings. It is intended that all such additional features and advantages be included therein with the scope of the present invention, as defined by the claims. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present invention. In the drawings, like reference numerals designate corresponding parts throughout the several views. 
     FIG. 1 is a front perspective view of a data storage component constructed in accordance with the present invention including a plurality of data storage modules inserted therein. 
     FIG. 2 is a fragmentary, rear perspective view of the data storage component shown in FIG.  1 . 
     FIG. 3 is a fragmentary, rear perspective view of a power supply module used in the data storage component shown in FIGS. 1-2. 
     FIG. 4 is a fragmentary, rear perspective view of an air mover pack used in the data storage component shown in FIGS. 1-2. 
     FIG. 5 is a schematic view of the data storage component shown in FIGS. 1-2 depicting the pattern of airflow within the component. 
    
    
     DETAILED DESCRIPTION 
     Referring now in more detail to the drawings, in which like reference numerals indicate corresponding parts throughout the several views, FIGS. 1-2 illustrate an electrical component  10  having a hybrid air cooling system constructed in accordance with the present invention. Typically, the electrical component  10  is a data storage component. Although the component  10  is described herein as a data storage component, it is to be understood that the component could be any electrical component that internally generates heat that is to be dissipated. 
     The electrical component  10  comprises a substantially rectilinear enclosure  12  having front and rear ends  14  and  16 . Pivotally mounted at the front end  14  of the component enclosure  12  is an enclosure door  18  which provides access to a data storage module enclosure  20 . As indicated most clearly in FIG. 1, the module enclosure  20  is adapted to receive a plurality of data storage modules  22  in a plurality of bay slots  24 . As is further apparent from FIG. 1, the modules  22  are tightly packed within the module enclosure  20  such that only small air spaces  26  separate one data storage module from the next. 
     Each data storage module  22  generally comprises a data storage device  28 , such as a disk drive, and a module carrier  30 . As indicated in FIG. 1, the module carrier  30  is arranged such that the data storage device  28  is exposed to the ambient air. This open air configuration improves heat transfer from the data storage devices  28 . Mounted at the front of each module carrier  30  is a bezel  32  which includes a plurality of air inlets  34 . 
     Positioned inside the module enclosure  20  is a main circuit board generally referred to as a backplane  36 . The backplane  36  includes a plurality of electrical connectors  38 , such as multiple pin connectors, and a plurality of airflow openings  40 . Typically, there is one electrical connector  38  and one airflow opening  40  aligned with each bay slot  24  of the module enclosure such that each data storage module  22  aligns with its own electrical connector and airflow opening. 
     With reference to FIG. 2, the data storage component  10  further comprises a transverse wall  42  which spans the width of the data storage component. As shown in the figure, the transverse wall  42  is oriented substantially parallel to the backplane  36 . Together, the backplane  36  and the transverse wall  42  define a first air plenum  44  which, as discussed below, serves to balance the airflow along the width of the component. The transverse wall  42  includes a plurality of airflow openings  46  that typically are positioned so as to be aligned with the airflow openings  40  of the backplane  36  to enable air to flow from module enclosure  20 , through the backplane air openings  40  into the first air plenum  44 , and then through the transverse wall airflow openings  46 . 
     Extending from the transverse wall  42  to the end of the component enclosure  12  are longitudinal walls  48 . Normally, there are two such longitudinal walls  48  that are arranged in parallel with one another within the component enclosure  12 . At the front end of the longitudinal walls  48  is a plurality of perforations  50  which, like the airflow openings  46  of the transverse wall  42 , permit air to flow therethrough. Together, the longitudinal walls  48 , the transverse wall  42 , and the walls of the component enclosure  12  define power supply module housings  52 . Similarly, the transverse wall  42 , the longitudinal walls  48 , and the walls of the component enclosure define a second air plenum  53 . Extending between the longitudinal walls  48  in substantially parallel planes is a plurality of trays  54  that, together with the longitudinal walls define, in descending order, a first daughter board housing  56 , a first air mover pack housing  58 , a second air mover pack housing  60 , and a second daughter board housing  62 . 
     FIGS. 3 and 4 depict a power supply module  64  and a modular air mover pack  66 , respectively, which are adapted to be slidably inserted into one of the power supply module housings  52  and one of the air mover pack housings  58  or  60 , respectively. As shown in FIG. 3, the power supply module  64  comprises a substantially rectilinear enclosure  68  that includes front and rear ends  70  and  72  and a top side  74 , a bottom side  76 , a front side  78 , a rear side  80 , and opposed lateral sides  82 . At the front end  70  of the enclosure  68  is a plurality of perforations  84 . Normally, these perforations  84  are provided on the front and lateral sides  78  and  82  of the enclosure  68  and together form an air inlet. Similarly, the rear end  72  of the enclosure  68  is provided with a plurality of perforations  86 . These perforations  86  are normally formed on the rear side  80  of the enclosure and to form an exhaust outlet. Attached to the rear side  80  of the module  64  is a handle  88  which facilitates insertion and removal of the module  64  into the component enclosure  12 . Mounted within the power supply module  64  is a set  89  of at least two air movers  90 . As indicated in FIG. 3, the air movers  90  typically take the form of axial fans which are mounted directly adjacent each other in series such that the forward-most air mover exhausts towards the rearward-most air mover. 
     When the power supply module  64  is slidably received within the power supply module housing  52  of the component enclosure  12 , the perforations  84  of the power supply module  64  are positioned adjacent to the airflow openings  46  of the component transverse wall  42  and the perforations  50  of one of the component longitudinal walls  48 . Arranged in this manner, air flowing from the front of the component enclosure  12  to the rear of the enclosure can pass through the transverse wall  42  and into the power supply module  64  where it is drawn rearwardly by the air movers  90  positioned therein until finally being exhausted out from the power supply module through its exhaust outlet. 
     As illustrated in FIG. 4, the air mover pack  66  comprises a substantially rectilinear enclosure  92  that includes front and rear ends  94  and  96 , and at least top and rear sides  98  and  100 . The top side  98  is provided with at least one perforated area  102  which forms an air inlet. In addition, the rear side  100  of the enclosure  92  is provided with a plurality of perforations  104  which form an exhaust outlet. Mounted inside the pack enclosure  92  is a set  105  of at least one air mover  106 . Normally, two such air movers  106  are arranged directly adjacent each other in series, each being formed as a centrifugal fan having an inlet port  108  and an exhaust port  110 . The air movers  106  are positioned within the enclosure  92  such that the inlet ports  108  are aligned with one of the perforated areas  102  of the enclosure and the outlet ports  110  face the perforations  104  of the rear side  100  of the enclosure. Arranged in this manner, the air movers  106  can draw in air from outside the enclosure  92  through the perforated areas  102  and expel it from the enclosure through the perforations  104 . 
     When disposed in its air mover pack housing  58  or  60 , each air mover pack  66  is positioned such that the perforated areas  102  are aligned with inlet openings  112  provided in the trays  54  of the data storage component  10 . In the embodiment depicted in the figures, the top and bottom trays are provided with these inlet openings such that the air mover packs  66  can be inserted in the first and second air mover pack housings  58  and  60 . When placed within the component enclosure  12  in this manner, the air movers  106  of the first and second packs  66  can draw air from the second air plenum  53 , over the first and second daughter board housings  56  and  62 , respectively, to exhaust this air from the rear end  16  of the component enclosure  12 . 
     The primary structural features of the invention having been described above, air cooling of the component  10  will be discussed with general reference to FIGS. 1-4 and with particular reference to FIG.  5 . When the electronic component  10  is operating, ambient air is drawn into the component enclosure  12  through the front end  14  of the enclosure. In particular, this air is drawn into the module enclosure  20  through the air inlets  34  provided in the bezels  32  of the data storage modules  22  by the air movers  90  and  106  positioned within the component enclosure  12 . Once inside the module enclosure  20 , the air flows past the data storage devices  28  and through the backplane airflow openings  40  into the first air plenum  44 . Because of the open air configuration of the data storage devices  28 , an adequate amount of heat is transferred from the devices to the airflow despite the extremely close packing of the modules  22  within the module enclosure  20 . 
     Once inside the first air plenum  44 , the airflow is balanced such that a generally equal air pressure distribution is obtained across the width of the component enclosure interior. From this point, the air is drawn through the airflow openings  46  provided in the transverse wall  42  and into the power supply module housings  52  and the second air plenum  53 . At this point, the airflow is divided along four different paths. A portion of the air is drawn into the power supply modules  64  through the perforations  84  formed in the front end  70  of the power supply module enclosure  68 . Once inside the power supply modules  64 , the air is drawn through the air movers  90  mounted therein and then expelled out from the power supply module rear ends  72 . A portion of the air in the second air plenum is drawn past first and second daughter boards (not shown) positioned within the first and second daughter board housings  56  and  62 , through the inlet openings  112  provided in the trays  54 , through the perforated areas  102  of the air mover packs  66 , and into an air mover  106  to be expelled from the rear end  16  of the component housing  12 . 
     As indicated above and in the figures, each air mover is used in conjunction with a similar air mover such that there is air mover redundancy. Constructed in this manner, adequate heat dissipation can be obtained even if one of the air movers fails. For example, if one of the air movers  90  disposed within the power supply module  64  were to fail, the other air mover  90  would still operate to draw and exhaust the cooling air within the system. Similarly, if one of the air movers  106  disposed in the air mover pack housings  58  or  60  should fail the other air mover  106  would still operate to draw in air from its associated daughter board housing and expel the air from the rear end of the component enclosure  12 . In that positive airflow is maintained throughout each section of the component enclosure  12 , no flapper doors are needed to prevent reverse flow into the enclosure. The airflow within the enclosure is therefore not disrupted to a large degree when one of the air movers fails. Because of this fact, the data storage or other electrical devices to be cooled are prevented from overheating until such time when the inoperative air mover can be replaced. Moreover, due to the modular construction of the power supply modules  64  and the air mover packs  66 , the entire sub-component containing the inoperative air mover can be quickly removed and replaced with the system online, thereby reducing system downtime. 
     While preferred embodiments of the invention have been disclosed in detail in the foregoing description and drawings, it will be understood by those skilled in the art that variations and modifications thereof can be made without departing from the spirit and scope of the invention as set forth in the following claims. In particular, it is to be understood that, although the air cooling system is described in reference to a data storage component, the air cooling system could be used in any electrical component which internally generates heat that must be dissipated.