Abstract:
An embodiment includes a transparent sash mounted integral to the perforated doors on racks which hold computer servers typically installed in data centers. The racks are arrayed in rows forming cold aisles and hot aisles. Cooled air introduced into the cold aisle flows through the racks and cools the servers, and subsequently is removed from the hot aisle. Embodiment sashes slide vertically and extend above the tops of the racks and form a sealing relationship with the data center ceiling and adjacent sashes, thereby preventing wasteful mixing and recirculation of cooled and heated air over the tops of the racks. Embodiments are raised and lowered manually or automatically. The controls for the movement of the sashes are tied to the building automation and fire alarm systems and the sashes are lowered automatically upon activation of the data center fire suppression system, thereby complying with code requirements and avoiding interference with the fire sprinkler and suppression systems.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    This application relates to the control and management of cooling airflow in computer data centers. 
         [0003]    2. Description of Related Art including information disclosed under 37 CFR 1.97 and 1.98 
         [0004]    The cooling of computer servers in data centers, sometimes termed “IT or electronic servers”, presents significant problems in efficient energy consumption. The computer servers typically are stacked on shelves in enclosed racks or cabinets some up to seven feet high, three feet wide, and four feet deep. Doors on the front and back sides of the racks retain the servers in the racks and control access to the servers. The front and back doors of the racks are perforated so that cooling air enters through the perforations in the front door, flows over the enclosed computer server, thereby cooling the heat generating processors, and the now heated air exits through the rear door of the rack. Racks are aligned in a data center in arrays of 15 to 20 racks in such a manner that all the front doors of the racks are on the same side of the array. Two parallel arrays of racks with the front doors facing each other constitute a “cold aisle.” The rear doors of racks in each array are adjacent to the rear doors of a parallel array with the space between the rear doors of the arrays constituting a “hot aisle.” The aisles allow access to the front doors and to the rear doors of the racks for purposes of inspection, maintenance, or replacement, of the computer servers contained within the racks. 
         [0005]    Cooled air is introduced into a cold aisle, typically through perforated floor tiles in a raised access floor or through overhead ductwork. The cooled air within the cold aisle is drawn into the perforations in the front doors by fans in the computer servers; the air cools the computers; and the now heated air is extruded through the perforated back door into the hot aisle. Such heated air is then cooled by air conditioning apparatus and returned to the cold aisle or simply extruded from the data center. 
         [0006]    The above cold aisle—hot aisle system suffers significant inefficiencies which stem from the mixing and recirculation of air between the cold aisle and the hot aisle over the top of the racks. The energy expended in the cooling of air which mixes above the racks is wasted, as that cooled air never is used to cool the computer servers. 
         [0007]    A variety of containment approaches have been proposed to reduce or remove this inefficiency. The containment situation is complicated by the requirement that the space above the racks be free of obstructions for the proper flow of water from automatic sprinklers activated in case of a fire event. The following prior art represent approaches to solving this problem. 
         [0008]    U.S. Pat. No. 6,672,955 discloses an Internet Data Center with a plenum below the floor for fresh air which opens to a cold aisle tunnel. Heated air freely flows upward from the hot aisle and is collected at a plenum at the top of the Center. 
         [0009]    U.S. Pat. No. 7,403,391 discloses a data center with a number of embodiments, all of which involve a cooling unit positioned adjacent to a rack. In some embodiments flat or curved panels are located at the top of the racks, which restrict but don&#39;t prevent airflow between aisles. 
         [0010]    U.S. Pat. No. 7,542,287 discloses racks which are fully enclosed except for the front side which admits cooled air and with ducts at the top for removal of heated air. 
         [0011]    U.S. Pat. No. 7,667,965 discloses acoustically absorptive vertical anti-recirculation panels fixed by L shaped brackets to tops of adjacent racks. 
         [0012]    U.S. Pub. Pat. Applic. No. 2006/0260338 discloses a system of baffles, doors, and slanted baffles attached to the top of racks to impede the horizontal flow of warm air from a hot aisle to a cold aisle. 
         [0013]    U.S. Pub. Pat. Applic. No. 2009/0173017 discloses partitions on the tops of racks which are normally in the vertical position to inhibit unwanted airflows. The partitions are hinged at the attachment to the rack and are supported by guy-wires with fusible trigger-point assemblies which releases the partitions at a predetermined temperature, allegedly restoring the unrestricted gap between rack top and ceiling required by the fire-code. 
         [0014]    U.S. Pub. Pat. Applic. No. 2010/0000953 discloses modular blocking panels which close off unused sections of a rack. 
         [0015]    U.S. Pub. Pat. Applic. No. 2010/0061057 discloses modular panels which extend from adjacent racks to form a ceiling over a hot or cold aisle. 
         [0016]    U.S. Pub. Pat. Applic. No. 2010/0108272 discloses a curtain-like roll-up air barrier with a spring-loaded roller fastened to the ceiling and with the bottom fastened to a hold down structure located on top of an IT rack. Water soluble loops fasten the barrier to the hold down structure and are designed to release the barrier when wetted by a sprinkler system. 
         [0017]    U.S. Pub. Pat. Applic. No. 2010/0190430 discloses a computer room air conditioning system with a physical separation on the top of racks separating the hot and cold aisles. 
         [0018]    None of the discovered prior art solves the problems solved by embodiments of the present disclosure. In particular, embodiments solve the problems of preventing mixing of cooled and heated air above the racks while meeting the fire suppression requirements, and have the further advantages of allowing installation, inspection, replacement, or maintenance of individual racks and servers contained within the racks without interruption to working data centers. In addition, embodiments can be installed without the requirement of interruption to working racks and the IT servers within the racks. 
         [0019]    The foregoing examples of the related art and limitations related therewith are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings. 
       BRIEF SUMMARY OF THE INVENTION 
       [0020]    A system for controlling the flow of air over the top of racks containing computer servers arrayed in rows in a room was disclosed. The system comprised: A computer rack door with openings which allow air flow through the door. Channels are attached to the sides of the door, arrayed parallel to the sides of the door, with the tops of the channels near the top of the door. A rectangular air impermeable sash was capable of mounting on the door through interaction of the side edges of the sash with the channels. The sash was vertically movable from a lower position wherein the top edge of the sash is approximately adjacent to the top edge of the door, and the upper position in which the top edge of the sash is capable of touching the ceiling of the room. There are seals on both the top edge and the two side edges of the sash. When in the upper position the seal on the top edge is capable of a sealing interaction with the ceiling, and when in the upper position the seals on the side edges of the sash are capable of a sealing interaction with seals on adjacent sashes which are also in the upper position. An elevation mechanism is capable of elevating and lowering the sash between the lower and upper positions. The elevation mechanism is capable of operation in response to signals from a control mechanism. There is a control mechanism capable of signaling the elevation mechanism. Embodiments can be mounted on either the front door or rear door of a rack. 
         [0021]    The following embodiments and aspects thereof are described and illustrated in conjunction with systems, tool and methods which are meant to be exemplary and illustrative, not limiting in scope. In various embodiments, one or more of the above-described problems have been reduced or eliminated, while other embodiments are directed to other improvements. 
         [0022]    In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the drawings and by study of the following descriptions. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) 
         [0023]      FIG. 1  is a perspective view of the interior of a data center showing an array of server racks each with a first embodiment sash system mounted on the front door. 
           [0024]      FIG. 2  is a perspective view of a rack with a first embodiment sash system with the rack front door open and the sash in the lower position. 
           [0025]      FIG. 3  is a cross-sectional view of the upper region of a rack door showing a first embodiment elevation device. 
           [0026]      FIG. 4  is a cross-sectional view of the upper region of a rack door showing a second embodiment elevation device. 
           [0027]      FIG. 5  is a front view of an elevated sash showing the relationship between adjacent sashes, a data center suspended ceiling, and a data center sprinkler system. 
           [0028]      FIG. 6  is a front view of an elevated sash showing a manual embodiment sash. 
           [0029]      FIG. 7  is a cross-sectional view taken at  7 - 7  of  FIG. 6  showing a manual embodiment sash elevation and locking mechanism. 
           [0030]      FIG. 8  is a cross-sectional view taken at  8 - 8  of  FIG. 6  showing a manual embodiment sash locking mechanism. 
           [0031]      FIG. 9  is a front view of an array of racks showing the embodiment in which the sash is attached to the back door of the rack. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0032]      FIG. 1  is a perspective view of the interior of a data center showing an array of server racks each with a first embodiment sash system. The sash system is comprised of a sash, sash mounts, elevation mechanism, and control system. The first embodiment sash system is connected to the rack front door. Visible in  FIG. 1  is the data center floor  10 , the cold aisle  11  through which cooled air is delivered, and the hot aisle  12  into which air which has been used to cool the computer servers is collected. An array  13  of racks is shown comprised of a multiplicity of similar individual racks  14 . Also visible is the individual rack front door  15  which has a multiplicity of ventilation holes  16 , and a rack handle  23  for opening the rack front door  15 . A transparent sash  17  is shown in the upper position in which it extends above the rack top  20 . The top gasket  18  at the top edge  35  interacts with and has a sealing relationship with the data center ceiling (not shown in  FIG. 1 ). A left gasket  21  is located at the left side of the sash  17  and a right gasket  22  is located at the right side of the sash  17 . Interaction between the right gasket  22  of sash  17  on rack  14  and the left gasket  38  of sash  37  of adjacent rack  57  seals the sashes  17  and  37  between adjacent racks. Similar gasket interactions between sashes in the array seal the area above the racks in the array and below the ceiling. 
         [0033]      FIG. 2  is a perspective view of a rack  14  with a first embodiment sash  17  with the rack door or front side  15  open and the sash in the lower position. Visible in FIG. 
         [0034]      2  are ventilation holes  16  in the rack door or front side  15 , and hinges  26  which attach the rack front door to the rack. A number of shelves  27  vertically arranged within the rack are visible, with servers  28  sitting on the shelves. In  FIG. 2  the sash  17  is in the lowered position. The sash  17  is mounted and retained between two U-shaped channels  25  attached to the inside of the front door  15 . Also visible in  FIG. 2  are the elevation mechanisms  24  which raise and lower the sash. When the sash  17  is in the lowered position the top gasket  18  is approximately level with the top of the door and the top  20  of the rack  14 . 
         [0035]      FIG. 3  is a vertical cross-sectional view of the upper region of a rack door showing a first embodiment elevation mechanism in a partially elevated position. Visible in  FIG. 3  is the door frame  29 , the door  15  with ventilation holes  16  and U-shaped channel  25 . The sash  17  is shown retained within the U-shaped channel  25 . In the first embodiment elevation mechanism an elongated screw  32  is connected to the bottom edge of the sash  17  via a bushing  39 . A nut  33  is firmly attached to the inside of the U-shaped channel  25 . The screw  32  is rotated by the screw rotator  34  to raise or lower the sash. Similar elevation devices are located on each side of the sash. Also visible in  FIG. 3  is an optional battery  51 . The battery provides power to the screw rotator  34  and automatically lowers the sash to lowest position in the event of failure of both the main power source and back-up power source to the data center. 
         [0036]      FIG. 4  is a vertical cross-sectional view of the upper region of a rack door showing a second embodiment elevation mechanism in a partially elevated position. Visible in  FIG. 4  is the door frame  29 , the door  15  with ventilation holes  16  and U-shaped channel  25 . The sash  17  is shown retained within the U-shaped channel  25 . In the second embodiment a notched rod  230  is connected to the bottom edge of the sash  17 . The rod  30  is raised or lowered by a geared rotator  231  to raise or lower the sash. Similar elevation devices are located on each side of the sash. Also visible in  FIG. 4  is an optional battery  251 . The battery provides power to the gear rotator  231  and automatically lowers the sash to lowest position in the event of failure of both the main power source and back-up power source to the data center. 
         [0037]      FIG. 5  is a front view of an elevated sash showing the relationship between adjacent sashes, a data center suspended ceiling, and a data center sprinkler system. Visible in  FIG. 5  are the data center roof structure  41 , suspender wires  40  which connect the roof structure  41  with the data center ceiling  19  and support the ceiling  19 .  FIG. 5  shows the interactions between the left rack  53  and right rack  54  and the ceiling  19 . Visible in  FIG. 5  are the left U-shaped channel  25  and right U-shaped channel  38  of the left  53  and right  54  racks. In  FIG. 5  the sashes  17  are in the raised or upper position in close proximity to the ceiling with the top sash gaskets  18  forming a sealing relationship with the ceiling  19 , such sealing relationship preventing or inhibiting the passage of air over the tops of the sashes. In addition, the sashes in the upper position prevent the passage of air over the tops  20  of the left  53  and right  54  racks. The sash bottom edges  49  do not extend above the tops  20  of the racks. Sprinkler heads  42  mounted on the ceiling  19  also are shown. A sealing relationship is formed between the right gasket  22  of the left rack  53  sash and the left gasket  21  of the right rack  54  sash. The control boxes  50  mounted on the U-shaped channels  25  of left  53  and right  54  racks are also shown in  FIG. 5 . 
         [0038]      FIG. 6  is a front view of an elevated sash showing a manual embodiment sash. This manual embodiment sash  317  is moved between the upper and lower positions by an operator using the handle  348 . Upper seal  18 , left seal  21  and right seal  22  are shown on the edges of the sash  317 . The sash  317  is mounted between the left U-shaped channel  325  and right U-shaped channel  338 . Connected to the left channel  325  is a left square conduit  343  and connected to the right channel  338  is a right square conduit  355 . 
         [0039]    A slot (not visible in  FIG. 6 ) is located in the side of the square conduit which is attached to the back of the U-shaped channel and extends through both the square conduit and U-shaped channel and extends through the length of the conduits and U-shaped channels. Additional detail on the conduits, channels, and slots are found in  FIG. 8 . A left piston  345  is capable of vertical movement within the left square conduit  343 . A left piston arm  346  is attached at an approximately right angle to the piston, and the arm extends through the slot in the conduit and the U-shaped channel and is attached to and supports the bottom edge  349  of the sash  317 . Similarly, a right piston  365  and right piston arm  366  also support and are connected to the bottom edge  349  of the sash  317 . A control box  350  for controlling the locking mechanism is shown in  FIG. 6 . One embodiment mechanism for retaining the sash in a raised position is shown in  FIG. 7 . 
         [0040]      FIG. 7  is a vertical cross-sectional view taken at  7 - 7  of  FIG. 6  showing a manual embodiment sash elevation and locking mechanism. In this embodiment the sash is retained in a raised position by electromagnets. Visible in  FIG. 7  is the sash  317  and handle  348  which is used for manually raising and lowering the sash. Also visible is the left seal  321  attached to the sash left edge  336 . In this embodiment the seal is comprised of grommet filaments which are compressed by the U-shaped channel  325  when in the lowered position and extend fully to interact with an adjacent grommet when extended above the top  20  of the rack. Also visible in  FIG. 7  is the back side  326  of the left U-shaped channel  325 . The left U-shaped channel  325  is attached to the left square conduit  343 , of which the back edge  350 , left edge  351 , and front edge  353  of the square conduit are visible in  FIG. 7 . A multiplicity of electromagnets  347  are arrayed along the back edge  350  of the square conduit. Also visible is the piston  345  with an arm  346  which extends from the piston and is connected to and supports the bottom edge  349  of the sash  317 . The piston  345  may be moved vertically within the square conduit  343  and retained at any level by activation of the electromagnets which are arrayed along the back edge  350  of the square conduit. De-activation of the electromagnets allows the piston and attached sash to move to a lower position by the action of gravity. Also visible in  FIG. 7  is the rack door  15  and ventilation holes  16  in the door. 
         [0041]      FIG. 8  is a cross-sectional view taken at  8 - 8  of  FIG. 6  showing a manual embodiment sash locking mechanism. Visible in  FIG. 8  is the left square conduit  343  comprised of a left edge  351 , back edge  350 , right edge  352  and front edge  353  of the square conduit. A slot  344  extends through the length of the front edge  353  of the square conduit. Attached along the length of the left square conduit  343  is the left U-shaped channel  325 . The left U-shaped channel  325  is comprised of a back edge  328 , left edge  326 , and right edge  327 . The back edge  328  of the left U-shaped channel  325  is attached along its length to the front edge  353  of the left square conduit  343 . The slot  344  which extends through the front edge  353  of the left square conduit  343  also extends through the back edge  328  of the left U-shaped channel  325 . Also visible in  FIG. 8  is the piston  345  with attached arm  346 . An electromagnet  347  is visible on the back edge  350  of the left square conduit  343 . 
         [0042]      FIG. 9  is a front view of an array of racks showing the second embodiment sash system in which the sash  417  is attached to the back door  56  of the rack  14 . Other elements of the second embodiment sash system, such as the sash mounts, the elevation mechanism, and the control mechanism, are the same as in the first embodiment in which the sash is attached to the rack front door. Visible in  FIG. 9  is the data center floor  10 , the cold aisle  11  through which cooled air is delivered, and the hot aisle  12  into which air which has been used to cool the computer servers is collected. An array  13  of racks is shown comprised of a multiplicity of similar individual racks  14 . Also visible is the individual rack front door  15  which has a multiplicity of ventilation holes  16 , and rack handle  23  for opening the rack door  15 . A transparent sash  417  is shown in the upper position in which it extends above the rack top  20 . The top gasket  418  at the top edge  435  interacts with and has a sealing relationship with the data center ceiling (not shown in  FIG. 9 ). A left gasket  421  is located at the left side  436  of the sash  417  and a right gasket  422  is located at the right side  437  of the sash  417 . Interaction between the right gasket  422  of sash  417  on rack  57  and the left gasket  421  of sash  417  of adjacent rack  14  seals the sashes  417  between adjacent racks. The top edge gasket  418  is located at the top edge  435  of the sash  417 . The top edge gasket  418  seals the top edge  435  of the sash  417  against the ceiling (not shown in  FIG. 9 ). The right side U-shaped channel  427  is visible at the rear side  56  of the rack  14 . 
         [0043]    The second or back door or rear door embodiment sash system performs the same function as the first embodiment sash system, that of preventing or inhibiting the flow of air over the top of the racks in the array. By preventing the flow of air over the arrays, the efficiency of cooling in the data center is increased. The rear door embodiment has the advantage of being capable of installation without effecting the access into the rack for purposes of inspection, maintenance, replacement or installation of the computer servers in the rack. 
         [0044]    In embodiments sashes have seals attached to the two side edges and the top edge to create an air lock with the adjacent sash door or doors in the array and with the ceiling. These seals prevent circulation of hot air from the hot aisle back into the cold aisle, which results in wasted energy. The use of flexible seals at the top of the sash, and the ability to raise the sash just enough to contact the ceiling, allows the efficient sealing of the sashes despite irregularities and variations in the height of the ceiling. 
         [0045]    Embodiment seals are any suitable flexible, resilient materials capable of sealing interaction between the top of a sash and the ceiling, as well as with seals on a sash on an adjacent rack. Embodiment seals are manufactured of strips or fibers of plastics and rubber. Embodiment seals are grommet brushes. 
         [0046]    Grommet seals are comprised of fibers or filaments arranged in an extended array and retained at one end of the filaments by a filament holder. Such grommet seals are often used to seal against air penetration areas in data centers where electrical cables penetrate the floor or there are other unsealed floor openings. 
         [0047]    Embodiments include filaments of diameter of 0.010 inch to 0.036 inch. Such fibers typically have a length of 3 inch to 6 inches. Suitable materials for fibers include nylon Type 6. Suitable grommet seals include Item No. 10012 Extended Raised Floor Grommets available from Upsite Technologies, Albuquerque, New Mexico. 
         [0048]    The control mechanism can be activated in two ways. Control buttons on the rack door control the movement of the sash to the upper position or the lower position or any position in between. For example, the control buttons are used to lower the sash when it is desirable to open the door for inspection, maintenance, or replacement of the computer servers contained within the rack. After the servicing is complete, the control buttons are used to raise the sash to a sealing relationship with the ceiling and adjacent elevated sashes. 
         [0049]    The second method of activating the control mechanism is automatic and is controlled by the fire detection and response system. A data center generally has a smoke detection and a sprinkler system located on the ceiling. In the event of a fire the smoke detection and sprinkler systems are activated and a fire alarm is sounded. Embodiments of the present application also respond to the event of a fire with automatic activation of the control mechanism with movement of the sash to the lower position. The sash also is automatically lowered using an optional battery when both the conventional or mains source of electricity is interrupted and the back-up source of electrical power is also interrupted. In manual embodiments the sash is automatically lowered by gravity through the release of electromagnets when the fire detection and sprinkler system is activated or when both the conventional or mains source of electricity is interrupted and the back-up source of electrical power is also interrupted. This insures that the spray of water or other fire-extinguishing fluid from the sprinkler system would not be blocked by the sash but will be capable of uninhibited penetration into the arrays of racks and aisles with extinguishment or containment of the fire. 
         [0050]    In embodiments the sash is transparent or translucent in order to maximize the efficiency of a lighting system mounted in or on the ceiling of the data center. 
         [0051]    Embodiment sashes are manufactured by any suitable strong, hard, transparent or translucent material such as poly (methyl methacrylate), polycarbonate, polystyrene, polyvinyl chloride, polyethylene terephthalate, polyethylene, polypropylene, or other suitable plastic. Embodiments also are manufactured of glass, such as soda lime glass or borosilicate glass. 
         [0052]    Embodiment sashes also can be manufactured of opaque materials for use in data centers where lighting efficiency is not a factor. Embodiment materials for such sashes include steel, aluminum, iron, and copper. 
         [0053]    Embodiments, when installed with sashes in the elevated or upper position, accomplish a containment of the cold aisle and inhibit the movement and recirculation of cooled air or heated air over the tops of the racks, thereby increasing the efficiency of server cooling. Use of embodiments insures maximum efficiency in use of cooled air in maintaining the servers at optimum temperature. 
         [0054]    Embodiments are suitable for retrofitting into existing racks. Furthermore, retrofitting can be done without interruption of the operations of an ongoing data center, thereby contributing to the profitability of operations of the center. 
         [0055]    Embodiments also solve code compliance issues related to fire suppression and obstructions near the ceiling of a room. Use of the movable sash integral to the rack and tied to the fire alarm system enables an obstruction free area for the sprinkler systems and the fire suppression systems to work properly according to code. 
         [0056]    While a number of exemplary aspects and embodiments have been discussed above, those of skill in the art will recognize certain modifications, permutations, additions and sub combinations thereof It is therefore intended that the following appended claims and claims hereafter introduced are interpreted to include all such modifications, permutations, additions and sub-combinations as are within their true spirit and scope. The applicant or applicants have attempted to disclose all the embodiments of the invention that could be reasonably foreseen. There may be unforeseeable insubstantial modifications that remain as equivalents.