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FIELD OF THE INVENTION  
       [0001]     Embodiments of the present invention are directed to cooling of rack-mounted devices, and more particularly to a data center infrastructure having a cooling system.  
       BACKGROUND OF THE INVENTION  
       [0002]     Electronic equipment racks generally are designed to receive a number of electronic components arranged vertically in the rack, mounted on shelves, and/or to front and rear mounting rails. The electronic equipment may include, for example, printed circuit boards, communications equipment, computers, including computer servers, or other electronic components.  
         [0003]     Electronic equipment housed in racks produces a considerable amount of heat, which undesirably affects performance and reliability of the electronic equipment. Often the heat produced by the rack-mounted components is not evenly distributed in the racks. Temperature gradients causing elevated inlet temperatures at tops of racks, for example, reduce equipment reliability substantially. Equipment reliability may be reduced by as much as half the reliability of specific equipment function for each 10° F. rise in temperature. Accordingly, rack-mounted computer systems typically require effective cooling systems to maintain operational efficiency. Cooling can be accomplished by introducing cooled air into an equipment rack causing the air to flow through equipment in the rack and exit the rack at an increased temperature, thereby removing some of the heat. The heat removed from the rack is typically returned into the room containing the racks and the entire room is cooled using a relatively large air conditioning system.  
       SUMMARY OF THE INVENTION  
       [0004]     A first aspect of the present invention is directed to a modular data center. The modular data center includes a plurality of racks, each of the racks having a front face and a back face, wherein the plurality of racks is arranged in a first row and a second row, such that the back faces of racks of the first row are facing the second row, and the back faces of the racks of the second row are facing the first row. The data center also includes a first end panel coupled between a first rack of the first row and a first rack of the second row, the first end panel having a bottom edge and a tope edge. Further, the data center includes a second end panel coupled between a second rack of the first row and a second rack of the second row, the second end panel having a top edge and a bottom edge, and a roof panel is included to couple between the top edge of the first panel and the top edge of the second panel.  
         [0005]     The modular data center can be designed so that the roof panel is coupled to a top portion of at least one rack of the first row and to a top portion of at least one rack of the second row, such that the roof panel, the first end panel, the second end panel, and the first and second rows of racks form an enclosure around an area between the first row of racks and the second row of racks. The plurality of racks can further include cooling equipment that draws air from the area, cools the air and returns cooled air out of the front face of one of the racks. At least one of the first end panel and the second end panel can include a door. Further, at least a portion of the roof panel can be translucent. The modular data center can have at least one rack that includes an uninterruptible power supply to provide uninterrupted power to equipment in at least one other rack of the plurality of racks. The first row of racks in the modular data center can be substantially parallel to the second row. In addition, the modular data center can be designed such that one of the plurality of racks includes cooling equipment that draws air from an area between the first row and the second row, cools the air and returns cooled air out of the front face of one of the racks.  
         [0006]     Another aspect of the present invention is directed to a method of cooling electronic equipment contained in racks in a data center. The method includes arranging the racks in two rows, including a first row and a second row that is substantially parallel to the first row, with a back face of at least one of the racks of the first row facing towards a back face of at least one of the racks of the second row. The method also includes forming an enclosure around an area between the first row and the second row, and drawing air from the area into one of the racks and passing the air out of a front face of the one of the racks.  
         [0007]     The method can include a further step of cooling the air drawn into the one of the racks prior to passing the air out of the front face. The step of forming an enclosure may include coupling first and second side panels and a roof panel between the first row and the second row. At least one of the first side panel and the second side panel may include a door and the roof panel can include a translucent portion. Additionally, the method can include using an uninterruptible power supply to provide power to equipment in the racks.  
         [0008]     Yet another aspect of the present invention is directed to a modular data center that includes a plurality of racks, each of the racks having a front face and a back face, wherein the plurality of racks is arranged in a first row and a second row, such that the back faces of the racks of the first row are facing the second row, and the back faces of the racks of the second row are facing the first row. The modular data center further includes means for enclosing a first area between the first row and the second row, and means for drawing air from the enclosed area, cooling the air, and returning cooled air to a second area.  
         [0009]     The means for drawing air can further include means for passing cooled air through the front face of one of the racks. The modular data center can also be comprised of means for providing uninterruptible power to equipment in the racks. Access means for allowing access into the first area may also be a design feature of the modular data center.  
         [0010]     The invention will be more fully understood after a review of the following figures, detailed description and claims. 
     
    
     BRIEF DESCRIPTION OF THE FIGURES  
       [0011]     For a better understanding of the present invention, reference is made to the figures which are incorporated herein by reference and in which:  
         [0012]      FIG. 1  is a perspective view of a modular data center cooling system for rack-mounted equipment in accordance with one embodiment of the invention;  
         [0013]      FIG. 2  is a top view of another modular data system, similar to the system of  FIG. 1 ; and  
         [0014]      FIG. 3  is a block flow diagram of a process of cooling equipment mounted in modular data centers in one embodiment of the invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0015]     Embodiments of the invention provide a data center infrastructure having a cooling system for cooling rack-mounted electronic equipment. Embodiments of the invention provide a modular data center for rack-mounted equipment, wherein the modular data center provides power distribution, cooling and structural support for the rack-mounted equipment. The power distribution unit and cooling is provided in some embodiments using redundant systems to prevent downtime due to electrical or mechanical failures. As understood by those skilled in the art, other embodiments are within the scope of the invention, such as embodiments used to provide infrastructure for equipment other than electronic equipment.  
         [0016]     A system for providing power distribution for rack-mounted equipment which can be used with embodiments of the present invention is described in U.S. patent application Ser. No. 10/038,106, entitled, “Adjustable Scalable Rack Power System and Method,” which is herein incorporated by reference.  
         [0017]     Referring to  FIG. 1 , a perspective view of a modular data center  10  is shown. The modular data center  10  includes a power distribution unit  14 , a power protection unit  12 , a floor mounted cooling unit  16 , equipment racks  18 , and a hot room  22 . The modular data center  10  also has a door  52  having a window  54 , a roof  56 , a cold water supply and return  60 , and a voltage feed  58 . The data center  10  is a modular unit comprised of the power distribution unit  14 , the power protection unit  12  the floor mounted cooling unit  16 , and equipment racks  18  positioned adjacent to each other to form a row  32  and a row  34 . Row  32  and row  34  are substantially parallel. The power distribution unit  14  and the power protection unit  12  can be located directly adjacent to one another, and can be located at the end of one of the rows. The floor-mounted cooling unit  16  may be located and positioned adjacent to the power distribution unit  14 . Remaining enclosures forming the at least one additional row in the data center  10  are equipment racks  18 . The hot room  22  is located between row  32  and row  34 , and rows  32  and  34  comprise two of the perimeter walls of the modular data center  10 .  
         [0018]     The power distribution unit  14  typically contains a transformer, and power distribution circuitry, such as circuit breakers, for distributing power to each of the racks in the modular data center  10 . The power distribution unit  14  provides redundant power to the racks  18  and can monitor the total current draw. An uninterruptible power supply can provide uninterruptible power to the power distribution unit  14 . Preferably, the power distribution unit  14  includes a 40 kW uninterruptible power supply having N+1 redundancy, where the ability to add another power module provides N+1 redundancy. In one embodiment of the invention, input power to the power distribution unit  14  is received through the top of the rack from a voltage feed  58 . In one embodiment, the voltage feed  58  is a 240 volt feed coupled to the power distribution unit  14  that enters through the roof panel  56 . Alternatively, the input power may be received from underneath the rack, as through a raised floor, or through the back of the rack.  
         [0019]     The power protection unit  12  provides redundant power protection for centralized information technology equipment, as is contained in the equipment racks  18 . The power protection unit  12  can have individual power modules and battery modules that can be individually added or removed to accommodate different load requirements. The use of multiple power modules and battery modules provides redundancy by allowing continued operation despite the failure of any one power module or battery module. For example, the power protection unit can include a Symmetra PX® scalable, uninterruptible power supply having a three-phase input and a three-phase output, available from American Power Conversion Corporation, of West Kingston, R.I., or the power protection unit can include one of the uninterruptible power supplies described in U.S. Pat. No. 5,982,652, titled, “Method and Apparatus for Providing Uninterruptible Power,” which is incorporated herein by reference.  
         [0020]     The floor mounted cooling unit  16  provides heat removal by use of a chilled water supply, which enters the unit through supply line  60 . Alternatively, the cooling units can provide heat removal using DX compressorized cooling via use of a direct expansion refrigerant-based unit, which can be in the unit itself. The cooling unit contains a primary chilled water coil and secondary direct expansion coil within the same frame. The cooling unit can be configured for air, water or glycol use. Cooled air can be released through the bottom of the unit or the top of the unit. In one embodiment of the invention, cool air is released from the cooling unit  16  out its front face, so that the air flow is from the back of the rack and out the front of the rack. The cooling unit  16  can further be configured as one, two or three modules. In the embodiment shown in  FIG. 1 , a three-module cooling unit is used.  
         [0021]     In the embodiment of  FIG. 1 , each of row  32  and row  34  is comprised of six racks. In embodiments of the invention, the number of racks and the function of the equipment in the racks can vary. In one embodiment of the invention, the racks  18  are modified standard 19 inch racks, such as those available from American Power Conversion Corporation of West Kingston, R.I., under the trade name NETSHELTER VX Enclosures®.  
         [0022]     The back face of each of the power distribution unit  14 , the power protection unit  12 , the floor mounted cooling unit  16 , and the equipment racks  18  faces the interior of the modular data center  10 , or the hot room  22 . Essentially, the back faces of the racks in row  32  face the back faces of the racks in row  34 . In one embodiment, the equipment racks  18  have their rear doors removed so that each rack  18  remains open to the inside of the hot room  22 . In the embodiment shown, the modular data center  10  contains seven equipment racks  18 . Alternatively, in another embodiment, six equipment racks  18  complete the rows, but more than seven equipment racks  18  can complete the rows contained in the data center  10  and can be adjacent to one another or adjacent to other enclosures in the data center  10 , such as the power distribution unit  14 , the power protection unit  12 , or the floor mounted cooling unit  16 .  
         [0023]     The door  52  located at the end of the row of racks is attached with hinges  53  to a detachable frame  55 . The detachable frame  55  is located behind the power protection unit  12 . The detachable frame may be positioned behind any one of the power protection unit  12 , the power distribution unit  14 , or the equipments racks  18 , depending on which of the units are positioned at the end of a row in the data center  10 . The detachable frame  55  allows the door  52  to be quickly removed for replacement of the power protection unit  12  if necessary. The hot room is accessible by the door  52  and can be monitored through the observation window  54 . Preferably, a door  52  is located at each end of the hot room  22 . Generally, the door  52  is a 2×36 inch insulated, lockable steel door having an insulated observation window  54 .  
         [0024]     The cold water supply and return  60  can enter the hot room through supply pipes into the roof  56  or directly into the roofs of the racks. The voltage feed  58  can also enter through the roof  56  or through the roofs of the racks. Alternatively, the cold water supply and return  60  and the voltage feed  58  enter the hot room through a raised floor on which the modular data center rests or from another location outside of the room and into the racks, such as into the sides of the racks.  
         [0025]     The roof panel  56  is preferably a semi-transparent plexiglass roof panel supported by steel supports  62  that are positioned at intervals along the length  72  of the data center  10 . The roof  56  extends to cover the top of the hot room  22  located in the middle of the rows of racks. The roof  56  can be easily detachable to allow for removal of racks  18  or the power protection unit  12  when necessary. A roof panel  56  constructed of semi-transparent plexiglass allows room light to enter the space defining the hot room  22 . Additionally, the plexiglass roof  56  is preferably substantially airtight.  
         [0026]     The hot room  22  is completely enclosed and has walls formed by the backside of the racks  18  and walls comprised of the door  52  attached at each end of the hot room  22 . Alternatively, panels without doors can be the walls that complete the hot room. The hot room  22  is a substantially airtight passageway when the roof panel  56  is in place. Thus, the modular data center  10  is an enclosed computer infrastructure defined on its outside perimeter by the front face of each of the racks  18 , power protection unit  12 , power distribution unit  14 , and cooling unit  16 , and having a hot room  22  in its midsection. The outside walls of the hot room formed by the doors  52  are a portion of two of the outside walls of the modular data center  10 .  
         [0027]     Referring to  FIG. 2 , a top view of a modular data center  10  in one embodiment of the invention is shown. The modular data center of  FIG. 2  is similar to that of  FIG. 1 , but has five racks in each of row  32  and row  34 , rather than the six racks in each row of  FIG. 1 . With like numbers referring to like embodiments, the modular data center  10  of  FIG. 2  is comprised of the power distribution unit  14 , the power protection unit  12 , the floor mounted cooling unit  16 , the equipment racks  18 , and the hot room  22 . The power protection unit  12  is positioned directly adjacent to one side of the power distribution unit  14 , while a floor-mounted cooling unit  16  is positioned on the other side of the power distribution unit. A service clearance area  20  surrounds the modular data center  10 . In  FIG. 2 , an embodiment of the invention is shown having six equipment racks  18  and a cooling unit  16  having two modules.  
         [0028]     The dimensions of the modular data center  10  depend on the number of racks included in each of the rows of racks. For example, and referring again to  FIG. 1 , a data center  10  having six equipment racks  18  can have a width of 120″, indicated by arrow  28 , a length of 120″, indicated by arrow  29 , and a height of 36″, indicated by arrow  24 . The height  24  of the data center can be 36″, while the service clearance is preferably 36″ in width  26 . With the inclusion of the service clearance  20 , the floor surface area for the data center  10  is, preferably, a length  30  of 192″ and a width  30  of 192″. Alternatively, and referring to  FIG. 2 , a data center  10  having seven equipment racks  18  can have a width of 120″ and a length of 144″, while the height of the data center  10  is 36″. With the inclusion of the service clearance  20 , the floor surface area for an alternate data center is 192″ by 216″. The dimensions of the modular data center are given only as examples, but can vary significantly depending upon the type and size of racks used to design the data center.  
         [0029]     The modular data center  10  is operational when provided with a source of chilled water  60  and a voltage feed  58 . The data center can include a number of different power input designs, but is preferably a 40 kW design, allowing 6.7 kW/rack in a system having six equipment racks  18 , or 5.7 kW/rack in a system having seven equipment racks  18 , for example. Cold water enters the floor mounted cooling units  16  via supply lines  60 . A common supply line  60  can provide cold water to one or more cooling units simultaneously, as the cooling units  16  are connected to the common supply  60  with flexible hose that is easily disconnected.  
         [0030]     The modular data center  10  provides cooling for equipment in the data center as follows. Air from the room, or ambient air, filters through the front of the racks  18  to cool the equipment stored in the racks  18 . Air enters through the front of the racks  18  and is expelled out of the backside of the racks  18 . As the air passes through the equipment racks  18 , the temperature of the air rises. The respectively warmer air is expelled into the hot room  22 . The hot room  22  contains the warm air and prevents the warm air from mixing with air in the surrounding room. The cooling unit  16  draws warm air from the hot room and return cool air to the room outside the data center  10 . The warm air enters the cooling units  16  directly from the hot room  22 . The cold water supply  60  acts within the cooling unit to lower the temperature of the air, and the cooled air is then released into the surrounding area. The air is recycled to the surrounding room at a substantially cooled temperature. For example, the cooling unit  16  generally receives air from the hot room at 95° F. and cools it to a temperature of approximately 72° F. before it is released into the area surrounding the data center  10 . The floor mounted cooling unit  16  operates at substantially higher supply and return temperatures, allowing realization of high capacity without latent heat removal.  
         [0031]     Referring to  FIG. 3 , with further reference to  FIGS. 1-2 , the data center  10  is configured to perform a process of cooling equipment stored in enclosed racks using an infrastructure having independent power and coolant supplies. The process  100  includes the stages shown, although the process  100  may be altered, e.g., by having stages added, deleted, or moved relative to the stages shown.  
         [0032]     The process  100  of  FIG. 3  includes stage  102 , wherein power is supplied from a power distribution unit to a plurality of equipment racks  18 . The equipment racks  18  may contain a variety of electronic equipment that requires a consistent power supply to avoid system downtime. A voltage feed  58  is connected to the power distribution unit  14 , and a power protection unit  12  is installed adjacent to the power distribution unit  14  to ensure redundant power supply.  
         [0033]     At stage  104 , the racks  18  draw cool air from the surrounding room through the front face of the racks  18 . There may, for example, be an air distribution unit within the racks and/or within equipment contained in the racks that draws the room air into the rack  18  and distributes the air throughout the rack to cool components contained in the rack. As the air passes through the rack  18 , the air increases in temperature.  
         [0034]     At stage  106 , the racks  18  expel the air at an increased temperature into the hot room  22 . The air is expelled out of the backside of the racks  18 . As described above, in one embodiment, the racks  18  do not have rear doors. In other embodiments, rear doors may be included on the racks with the warm air being expelled into the hot room through vents in the doors. Air is held in the hot room  22  at an increased temperature and mixing of the warm air with the surrounding ambient air is prevented.  
         [0035]     At stage  108 , the cooling unit draws the warm air from the hot room  22 . The cooling unit  16  uses the cold water from the cold water supply  60  to cool the air from the hot room. At stage  110 , the cooled air is released from the cooling unit into the surrounding room, which completes the cooling cycle. The air in the surrounding room is then drawn into the racks  18  once again, and the cycle continues.  
         [0036]     Other embodiments are within the scope and spirit of the appended claims. For example, air could be forced up through the equipment racks  18 . Air moved through the racks  18  could be of varying temperatures, including hot air. The data center  10  may be configured to distribute gases other than air. Additionally, a refrigerant or other coolant may be used rather than cold water. Further, a controller can be coupled to the data center  10  to monitor air temperatures and flow rates, as well as power supply so that each rack is provided adequate power consistently. A data center may contain a single equipment rack  18  having a single cooling unit  16  creating an individual data center, whereby power is distributed to a single data center  10  or multiple single-rack data centers simultaneously.  
         [0037]     Further, in embodiments of the present invention, the roof over the hot area may include a number of fans that are controlled to exhaust air from the hot area in the event of a failure of an air conditioning unit in the modular data center, and/or when air temperature in the hot area exceeds a predetermined limit.  
         [0038]     Having thus described at least one illustrative embodiment of the invention, various alterations, modifications and improvements will readily occur to those skilled in the art. Such alterations, modifications and improvements are intended to be within the scope and spirit of the invention. Accordingly, the foregoing description is by way of example only and is not intended as limiting. The invention&#39;s limit is defined only in the following claims and the equivalents thereto.

Summary:
A modular data center includes a plurality of racks, each of the racks having a front face and a back face, wherein the plurality of racks is arranged in a first row and a second row, such that the back faces of racks of the first row are facing the second row, and the back faces of the racks of the second row are facing the first row, a first end panel coupled between a first rack of the first row and a first rack of the second row, the first end panel having a bottom edge and a tope edge, a second end panel coupled between a second rack of the first row and a second rack of the second row, the second end panel having a top edge and a bottom edge, and a roof panel coupled between the top edge of the first panel and the top edge of the second panel.