Abstract:
According to the present invention, there is provided a system for removing heat from server blades densely packaged in a rack of server blades. The system includes a liquid distribution manifold. In addition, the system includes a plurality of cold blades attached to the liquid distribution manifold, wherein liquid is circulated through the liquid distribution manifold and the cold blades. Moreover, the system includes at least one server blade attached to each of the cold blades.

Description:
FIELD OF THE INVENTION 
   The present invention relates to computer cooling systems and, more specifically, to a system and method for providing the removal of heat from server blades densely packaged in a rack of server blades. 
   BACKGROUND OF THE INVENTION 
   Servers implemented as racks of full of blades (unpackaged printed circuit boards) are becoming increasingly popular because of their potentially high density. However, the difficulty of removing heat from such systems via forced air cooling has emerged as a very significant problem. It is so severe that in most actual datacenter installations blade server racks need to be kept half empty because they cannot be cooled with standard methods. 
   SUMMARY OF THE INVENTION 
   According to the present invention, there is provided a system for removing heat from server blades densely packaged in a rack of server blades. The system includes a liquid distribution manifold. In addition, the system includes a plurality of cold blades attached to the liquid distribution manifold, wherein liquid is circulated through the liquid distribution manifold and the cold blades. Moreover, the system includes at least one server blades attached to each of the cold blades. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows the interior layout of a rack for iceblades. 
       FIG. 2  shows two iceblades in close, direct thermal contact with a water-cooled coldblade. 
       FIG. 3  shows the cross-section of a generic iceblade. 
       FIG. 4  shows the cross-section of an iceblade holding disks. 
       FIG. 5  shows a pair of iceblades, one diskless and one with disks, embracing a coldblade. 
       FIG. 6  shows two diskless iceblades embracing a coldblade. 
       FIG. 7  shows the relative location of two clamps utilized in holding two iceblades together, where the iceblades surround a coldblade. 
       FIG. 8  shows a detailed view of the clamping mechanism utilized in holding two iceblades together, where the iceblades surround a coldblade, according to an exemplary embodiment of the invention. 
       FIG. 9  is a diagram showing how iceblades make contact with a backplane, according to an exemplary embodiment of the invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The invention describes a system and method for removing heat from server blades densely packaged in a rack of server blades. 
     FIG. 1  shows the interior layout of a rack for server blades (iceblades) within rack enclosure  10 . Rack enclosure  10  includes a water distribution manifold including manifold columns  14 , an upper portion  11  and a base portion  12 . Multiple coldblades  16  can be attached to each of the manifold columns  14 . Water flows horizontally through coldblades  16 . The coldblades  16  are accessible from the front of enclosure  10 . Airflow parallel to the coldblades  16  may be employed to remove residual heat which cannot be removed by the coldblades  16 . 
     FIG. 2  shows two iceblades  18  in close thermal contact with a coldblade  16 . In one embodiment, the coldblade  16  is water-cooled. Each iceblade  18  is a carrier for electronic components. Each coldblade  16  is tightly embraced by two iceblades  18 . 
     FIG. 3  shows a cross-section of an iceblade  18 . In one embodiment, Iceblade  18  consists of printed circuit board  20  and heat-conducting metal plate  22 . Major heat producing circuits (e.g., chips  24 ) on the printed circuit board  20  are in direct thermal contact with aluminum plate  22 . Heat spreading methods of various kinds may be employed to carry heat from dissipating electronic elements to aluminum plate  22 . In an exemplary embodiment, the space between printed circuit board  20  and aluminum plate  22  heat is filled with conducting polymer  26  or other materials, such as crushed copper wool. In another exemplary embodiment, metallic thermal shims may be used to carry heat form from dissipating electronic elements to aluminum plate  22 . Also, heat dissipating elements (e.g., DIMMS) can be mounted on the backside of printed circuit board  20 , where they are exposed to airflow. 
     FIG. 4  shows a cross-section of an iceblade  18  holding multiple disks  28 . The rigid surface of aluminum plate  22  makes it practical to rigidly mount disks  28 . In contrast, conventional blades are typically unable to hold more than one or two disks  28 . 
     FIG. 5  shows one embodiment of a field replaceable unit (FRU)  30 , consisting of a pair of iceblades  18 , one diskless and one with disks  28 , embracing a coldblade  16 . A clamping mechanism automatically clamps the two iceblades  18  onto the coldblade  16  upon insertion. The clamping mechanisms includes clamping unit  32 . 
     FIG. 6  shows another embodiment of field replaceable unit (FRU)  30 , consisting of a pair of diskless iceblades  18  embracing a coldblade  16 . 
     FIG. 7  is a diagram  36  showing the action associated with the insertion and removal of FRU  30  in conjunction with coldblade  30 . In diagram  36 , FRU  30  is shown with clamping unit  32  mounted on the top and bottom of FRU  30 . In diagram  36 , FRU  30  is inserted from the front of coldblade  16  towards manifold columns  14 . 
     FIG. 8  shows the details of an exemplary clamping unit  32  utilized by FRU  30 . Clamping unit  32  includes self-locking worm gear  40 , DC motor  42 , shaft  44 , steel nuts  46 . DC motor  42  drives worm gear  40  through shaft  44 . The ends of shaft  44  contain threads of opposite handedness (left handed and right handed, respectively) and engage nut  46  and nut  48 . Nut  46  and nut  48  are each embedded in iceblades  18 . 
   Application of DC voltage of one polarity to DC motor  42  will simultaneously draw iceblades  18  closer to coldblade  16 . Application of the opposite polarity will drive iceblades  18  apart. In a DC motor  42 , current draw and torque are nearly linearly related. This fact can be used to measure the applied torque and shut off the power when a pre-determined amount of torque or clamping force has been achieved. 
   Worm gear  40  is of self-locking design, where removing the voltage to the DC motor  42  will not result in a loosening of the clamping force. The axis of each DC motor  42  included in FRU  30  is extended to the front of the FRU  30  and fitted with a small handle. The small handle can be used to release FRU  30  in the event of the failure of DC motor  42 . 
     FIG. 9  shows one embodiment of the contact mechanism utilized in rack enclosure  10 , between iceblades  18  and backplane  46 . Extending perpendicular from backplane  46  two arrays of contact points  48 . Each iceblade  18  includes multiple contact blocks  50 . Contact blocks  50  penetrate aluminum plate  22 , so that they slightly protrude over the level of the mating surface of aluminum plate  22 . The protruding contact blocks make contact with corresponding contact points  48 . Clamping unit  32  provides the force necessary for contact between contact points  48  and contact blocks  50 . In an alternative embodiment, capacitive coupling mechanisms can be employed as well. 
   Thus, a system, method and service to provide a cooling system for high-powered compute and storage server blades have been described. Although the present invention has been described with reference to specific exemplary embodiments, it will be evident that various modifications and changes may be made to these embodiments without departing from the broader spirit and scope of the invention. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense.