Abstract:
A liquid submersion-cooled computer that is configured to reduce physical structures passing through walls of the computer liquid-tight computer case, which eliminates the amount of sealing needed around those physical structures and reduces the number of possible fluid leakage paths from the interior of the computer that contains a cooling liquid submerging at least some of the computer components. The computer includes a mechanism to pass input/output signals into and from the computer without any physical structure extending through any of the plurality of walls. The computer also has a mechanism for wirelessly transferring power into the interior space of the computer case, and a switch that controls power in the computer without having any physical structure extending through any of the plurality of walls.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application 61/378,044 filed Aug. 30, 2010, which application is incorporated by reference herein in its entirety. 
         [0002]    In addition, this application relates to U.S. Pat. No. 7,403,392; U.S. Publication No. 2008/0196870; U.S. Publication No. 2008/0017355; U.S. Pat. No. 7,724,517; U.S. Pat. No. 7,414,845; U.S. Publication No. 2009/0260777; U.S. application Ser. No. 12/795,854; and U.S. application Ser. No. 12/714,904, each of which is incorporated by reference herein in its entirety. 
     
    
     TECHNICAL FIELD 
       [0003]    This disclosure relates to a liquid submersion-cooled electronic system, and in particular, to a case that is used in a liquid submersion-cooled electronic device, for example, a computer such as a server computer or a personal computer. 
       BACKGROUND 
       [0004]    Typical computers are air cooled and thus the computer cases have openings allowing air flow into, through and out of the cases to allow the air to exchange heat with the computer electronics for cooling the electronics. However, conventional computer cases are not suitable for liquid submersion-cooled computers because the openings in the case would allow liquid to leak from the case. Sealing the openings is possible, although each sealed opening forms a possible leakage path for liquid to escape from the case. In addition, any joint between two separate physical structures of a computer case forms a possible leakage path. 
       SUMMARY 
       [0005]    A liquid submersion-cooled computer is described that is configured to reduce physical structures passing through walls of the computer liquid-tight computer case, which eliminates the amount of sealing needed around those physical structures and reduces the number of possible fluid leakage paths from the interior of the computer that contains a cooling liquid submerging at least some of the computer components. 
         [0006]    Examples of liquid submersion-cooled computers to which the concepts described herein include, but are not limited to, server computers such as blade servers and personal computers. The concepts described herein can also be applied to other liquid submersion-cooled electronic devices including, but not limited to, disk arrays/storage systems; storage area networks; network attached storage; storage communication systems; work stations; routers; telecommunication infrastructure/switches; wired, optical and wireless communication devices; cell processor devices; printers; power supplies; displays; optical devices; instrumentation systems, including hand-held systems; military electronics; etc. 
         [0007]    In one embodiment, the liquid submersion-cooled computer has a housing including a plurality of walls that define a liquid-tight interior space, a liquid inlet in a wall of the housing, a liquid outlet in a wall of the housing, and a dielectric cooling liquid disposed within the interior space. A logic board is disposed in the interior space of the housing, and heat generating computer components are disposed on the logic board. At least some of the heat generating computer components are submerged in the dielectric cooling liquid. 
         [0008]    In order for the computer to function, there must be some way to pass input/output signals into and from the housing, and to pass power into the housing to power the computer components and other components in the housing. In addition, most computers have an on/off power switch to turn the computer on and off. Typically, input/output, power and a power switch extend physically through one or more walls of the computer housing. However, in a liquid submersion-cooled computer, any structure passing through a wall of the housing must be sealed to prevent fluid leakage, and even if sealed, a potential leakage path is formed. 
         [0009]    To minimize the need for sealing and to reduce the number of leakage paths, in one embodiment the computer is provided with a means for passing input/output signals to/from the logic board, where the means for passing input/output signals does not have any physical structure thereof extending through any of the plurality of walls. The means for passing input/output signals can be any mechanism suitable for passing input/output signals into/from the housing without requiring any physical structure passing through a wall of the housing. For example, the means for passing input/output signals can be an optical input/output unit that is coupled to or near one of the walls, for example a front wall or a rear wall. To facilitate passage of optical signals, some or all of the front or rear wall can be optically transparent. 
         [0010]    In another embodiment, the computer is provided with a means for wirelessly transferring power into the interior space of the housing, where the means for wirelessly transferring power does not have any physical structure thereof extending through any of the plurality of walls. The means for wirelessly transferring power can be any mechanism suitable for wirelessly passing power through a wall of the housing without requiring any physical structure passing through a wall of the housing. For example, the means for wirelessly passing can be an induction mechanism such as an induction coupling, an electrodynamic induction mechanism, or an electrostatic induction mechanism. 
         [0011]    In another embodiment, the computer is provided with an on/off switch means for controlling power in the computer, where the switch means does not have any physical structure thereof extending through any of the plurality of walls. The on/off switch means can be any type of switch suitable for controlling power in the computer without requiring any physical structure passing through a wall of the housing. For example, the switch means can be a proximity switch that senses a person in proximity to the switch to switch power on or off. 
         [0012]    When the computer is, for example, a server computer, plurality of the server computers can be arranged in an array on a server rack. In addition, the computer can have a single logic board or a plurality of logic boards disposed within the interior space. Each logic board(s) includes a number of heat-generating components, including at least one processor, for example, a CPU or a GPU. In addition, other heat-generating components of the computer can be submerged in the cooling liquid, for example, power supplies, RAM, daughter cards and storage drives such as solid-state drives or mechanical hard drives. 
     
    
     
       DRAWINGS 
         [0013]      FIG. 1  illustrates a server computer case as described herein. 
           [0014]      FIG. 2  illustrates the server computer case of  FIG. 1  with one of the side walls removed to show the electronics within the case. 
           [0015]      FIG. 3  is a rear perspective view showing the rear wall of the case. 
           [0016]      FIG. 4  shows an example of the optical input/output unit. 
           [0017]      FIG. 5  shows an example of the transformer unit. 
           [0018]      FIG. 6  shows the rack system that holds the array of cases. 
       
    
    
     DETAILED DESCRIPTION 
       [0019]    A liquid submersion-cooled electronic device is described. Examples of electronic devices to which the concepts described herein can be applied include, but are not limited to: computers including server computers such as blade servers, and personal computers; disk arrays/storage systems; storage area networks; network attached storage; storage communication systems; work stations; routers; telecommunication infrastructure/switches; wired, optical and wireless communication devices; cell processor devices; printers; power supplies; displays; optical devices; instrumentation systems including hand-held systems; military electronics; etc. 
         [0020]    For sake of convenience, this description will describe the electronic device as a liquid submersion-cooled blade server computer. However, it is to be realized that the concepts described herein could be used on other liquid submersion-cooled electronic devices as well. 
         [0021]      FIGS. 1-3  illustrate a liquid submersion-cooled blade server computer  10  having a case or housing  12 . The case includes a plurality of walls that define a liquid-tight interior space  14 . The walls include a pair of side walls  16  (only one side wall is visible in  FIGS. 1-3 ), a top wall  18 , a bottom wall  20 , a front wall  22  and a rear wall  24 . The terms front, rear, top, bottom, and side refer to the relative positions of the walls when the computer  10  is properly oriented during use. 
         [0022]    When the walls are assembled together they form the liquid-tight interior space  14  which is designed to contain the server electronics and a cooling liquid that submerges some or all of the server electronics. The rear wall  24  includes a valved liquid inlet  26  and a valved liquid outlet  28  to allow cooling liquid to enter and exit the interior space  14 . Therefore, a liquid-tight interior space is intended to mean that there is no unintentional leakage or other unintentional discharge of cooling liquid from the interior of the case  12 , despite there being the ability for cooling liquid to intentionally flow into and out of the case  12  through the inlet and the outlet. Although the inlet  26  and the outlet  28  are illustrated in this embodiment as being in the rear wall  24 , the inlet and the outlet could be formed in other walls, for example the front wall  22 , and the inlet and the outlet need not be in the same wall. 
         [0023]    In use, the inlet  26  and the outlet  28  are connected to a thermal dissipation or recovery device (not shown). The thermal dissipation or recovery device can be any device that is suitable for dissipating heat or allowing recovery of the heat from the cooling liquid from inside the case. For example, the device can be a simple heat exchanger, such as a radiator, for dissipating heat. Air or liquid could be used as the heat exchanging medium. In addition, the heat exchanger could be disposed underground to allow the relatively cool ground to cool the liquid. The external heat exchanger can take on a number of different configurations, as long as it is able to cool the liquid down to an acceptable temperature prior to being fed back into the case. Examples of thermal dissipation devices include, but are not limited to, a cooling stack, evaporation, and an in-ground loop. A pump is used to pump the cooling liquid from the case, to the thermal dissipation or recovery device, and back into the case. Further information on thermal dissipation or recovery devices can be found in U.S. Patent Application Publication No. 2009/0260777, which is incorporated by reference in its entirety. 
         [0024]    With reference to  FIGS. 2 and 3 , a plurality of electronically and/or thermally active computer components that together form a complete computing system, for example forming a server computing system, are disposed within the case  12 . Examples of computer components that are electronically and/or thermally active include, but are not limited to, processors, one or more power supply units, memory and storage devices, management hardware, and other components. For a server computer, the computer components are mounted on a server logic board  40  that is suitably fixed in the interior space  14  of the case. 
         [0025]    A cooling liquid that submerges at least some or all of the heat generating components of the computer is within the interior space  14  so that the submerged components are in direct contact with the cooling liquid inside the case  12 . The cooling liquid can be, but is not limited to, a dielectric liquid. Dielectric liquids that can be used include, but are not limited to: 
         [0026]    Engineered fluids like 3M™ Novec™ 
         [0027]    Mineral oil 
         [0028]    Silicone oil 
         [0029]    Natural ester-based oils, including soybean-based oils 
         [0030]    Synthetic ester-based oils 
         [0031]    The cooling liquid can be single phase or two-phase. It is preferred that the liquid have a high enough thermal transfer capability to handle the amount of heat being generated by the submerged components so that the liquid does not change state. Enough of the liquid is present in the case  12  in order to submerge the heat generating components of the computer that one wishes to submerge. So in some instances the liquid may fill substantially the entire case  12 , while in other instances the liquid may only partially fill the case  12 . 
         [0032]    With reference to  FIG. 6 , a plurality of the server computers  10  can be arranged in an array on a server rack  50 . The rack  50  includes inlet  53   a  and outlet  53   b  manifolds disposed at the rear of the rack. The flow lines of the inlet and outlet manifolds  53   a ,  53   b  leading to each case  12  can utilize quick-disconnect valves that engage with quick-disconnect valves on the inlet  26  and the outlet  28 , so that the valves on the inlet and the outlet and the valves on the manifolds  53   a ,  53   b  can automatically open upon installation of a case and automatically close upon removal of the case. The quick-disconnect valves would allow the change-out of a failed server computer using a hot swappable system architecture. 
         [0033]    The rack  50  includes a frame  54 , a coolant return line  56  connected to the inlet manifolds  53   a  at the rear of the frame  54 , and a coolant outlet line  58  connected to the outlet manifolds  53   b . The computers  10  are each mountable on the frame  54  to support the computers in the desired array configuration. The frame  54  in  FIG. 6  is illustrated as being capable of supporting three vertically-spaced rows of computers that are slid into the frame  54 . Each computer  10  can be provided with means to facilitate sliding insertion and removal of the computer. 
         [0034]    Returning now to  FIGS. 1-3 , the computer  10  is provided with means  60  for passing input/output signals to/from the logic board into the case  12  and from the case  12 . To minimize sealing and reduce a potential leakage path, the means  60  for passing input/output signals to and from the computer  10  does not have any physical structure thereof extending through any of the plurality of walls. The means  60  for passing input/output signals can be any mechanism suitable for passing input/output signals into/from the case  12  without requiring any physical structure passing through a wall of the housing. In the embodiment illustrated in  FIGS. 2 and 3 , the means  60  for passing input/output signals is positioned to pass input/output signals through the rear wall  24 . However, the means  60  for passing input/output signals can be positioned to pass input/output signals through any of the walls, including the front wall  22 . 
         [0035]    Referring to  FIG. 4 , an example of the means  60  for passing input/output signals is illustrated in the form of an optical input/output unit that provides optical input/output connections. In this example, the unit is coupled to or near the rear wall  24  to enable external component IO and storage IO to pass into and out of the case  12  to and from the logic board  40  and its components. In this example, the optical I/O unit  60  includes an optical-to-digital/digital-to-optical converter mechanism  62 , such as, for example, a digital fiber optical-to-digital/digital-to-optical coaxial converter, that is disposed within the case  12  adjacent the rear wall  24 , for example mounted on the interior surface of the rear wall. The converter mechanism  62  receives optical signals through the rear wall that are then converted by the converter mechanism  62  into digital signals which are then distributed to the proper electronic components inside the case  12 . The converter mechanism  62  also takes digital signals from the electronic components inside the case  12  and converts them into optical signals for transmission outside the case  12 . 
         [0036]    The optical I/O unit  60  interfaces with a corresponding digital-to-optical/optical-to-digital converter mechanism  64  that is disposed on the backplane of the rack  50  as shown in  FIG. 6 . The converter mechanism  64  converts digital signals into optical signals for transmission into the case  12 , and receives optical signals from the case and converts the received optical signals into digital signals. As shown in  FIG. 4 , when the computer  10  is mounted in the rack, the rear wall  24  is adjacent to the converter mechanism  64  to permit the passage of optical I/O signals through the rear wall  24 . 
         [0037]    The converter mechanisms  62 ,  64  can employ one or more optical conduits  66 , such as, for example, optical lenses and optical fibers, to facilitate transmission of the optical signals between the converter mechanisms  62 ,  64 . The rear wall  24  should be optically transparent between the converter mechanisms  62 ,  64  to allow passage of the optical signals. For example, some or all of the rear wall can be made of a transparent material to make the rear wall light transmissive. For example, a transparent I/O window  66  ( FIG. 3 ) can be provided in the rear wall, or the entire rear wall can be made transparent. 
         [0038]    Referring to  FIGS. 1-3 , the computer  10  is also provided with means  70  for wirelessly transferring power into the interior space of the housing. To minimize sealing and reduce a potential leakage path, the means  70  for wirelessly transferring power does not have any physical structure thereof extending through any of the plurality of walls. The means for wirelessly transferring power can be any mechanism suitable for wirelessly passing power through a wall of the housing without requiring any physical structure passing through a wall of the housing. In the embodiment illustrated in  FIGS. 2 and 3 , the means  70  for wirelessly transferring power is positioned to pass power through the rear wall. However, the means  70  for wirelessly transferring power can be positioned to pass power through any of the walls, including the front wall  22 . The means  70  for wirelessly transferring power can be an induction mechanism, such as an induction coupling, an electrodynamic induction mechanism, or an electrostatic induction mechanism. 
         [0039]    One example of the means  70  for wirelessly transferring power is illustrated in  FIG. 5 . In this illustrated example, the means for wirelessly transferring power comprises an induction coil  72  inside the case  12  on or adjacent to the interior surface of the rear wall  24 . The induction coil  72  is positioned to interface with a power port  74  that includes an induction coil that is disposed on the backplane of the rack  50  as shown in  FIG. 6  when the computer is mounted on the rack  50 . As shown in  FIG. 5 , when the computer  10  is mounted in the rack, the rear wall  24  is adjacent to the induction coil of the power port  74  to permit the passage of optical I/O signals through the rear wall  24 . 
         [0040]    The induction coil of the power port  74  creates an alternating electromagnetic field. The electromagnetic field produces an electrical current in the induction coil  72  which is then used to provide power to the electronic components within the case  12 . Suitable electromagnetic shielding is provided around the power port  74  and the means  70  for wirelessly transferring power to prevent electromagnetic interference with adjacent computers in the rack and with electronic components inside the case  12 . 
         [0041]    Referring to  FIGS. 1-3 , the computer  10  is also provided with an on/off switch means  80  for controlling power in the computer. To minimize sealing and reduce a potential leakage path, the switch means  80  does not have any physical structure thereof extending through any of the plurality of walls. The on/off switch means can be any type of switch suitable for controlling power in the computer without requiring any physical structure passing through a wall of the housing. 
         [0042]    In the embodiment illustrated in  FIGS. 1-3 , the switch means  80  is a proximity switch that senses a person in proximity to the switch to switch power on or off. The switch means  80  could also be a touch switch where a user has to physically touch a wall adjacent the switch to activate the switch. For example, the touch switch can be a capacitance touch switch or a resistance touch switch. In the embodiment illustrated in  FIGS. 1-3 , the switch means  80  is positioned on or near the interior surface of the front wall  22 . However, the switch means  80  can be positioned adjacent any of the walls, including the rear wall  24 . 
         [0043]    The embodiments disclosed in this application are to be considered in all respects as illustrative and not limitative. The scope of the invention is indicated by the appended claims rather than by the foregoing description; and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein.