Abstract:
A system and method for cooling a plurality of connectors interfacing electrical and optical signals to circuit boards in an electronics cabinet, such as backplane connectors routing signals to circuit boards housed in card cage assemblies. Heat pipes coupled to the connectors efficiently remove heat from the connectors and sink the connector heat to a cold junction of a liquid cooling system, which cooling system may also extract heat from air flow cooling the circuit boards such that the system is room neutral, meaning that the ambient temperature remains constant during operation of the system. The heat connector cooling system is effective where connectors are outside of an air flow cooling envelope that may cool the circuit boards.

Description:
CLAIM OF PRIORITY 
     This application is a continuation-in-part of U.S. application Ser. No. 13/681,188 filed Nov. 19, 2012 entitled Transverse Cooling System and Method, which claims priority of U.S. Provisional Patent Application Ser. No. 61/561,240 filed Nov. 17, 2011 entitled Transverse Cooling System and Method. 
    
    
     GOVERNMENT RIGHTS 
     This invention was made with U.S. Government support under Agreement No. HR0011-07-9-0001 awarded by DARPA. The U.S. Government has certain rights in this invention. 
    
    
     FIELD OF THE INVENTION 
     The present invention is related to systems for cooling electronics, and more particularly to cabinet mounted electronics assemblies such as rack mounted circuit boards. 
     BACKGROUND INFORMATION 
     Conventionally, electronics cabinets such as those with rack mounted electronics, such as circuit boards and connectors, are cooled by directing cooled air vertically up through the cabinet. The cooled air typically enters the cabinet at or near the floor and the heated air exits at or near the top of the cabinet. Circuit boards are arranged vertically such that air flows bottom to top along the surfaces of the circuit boards, taking advantage of the fact that hot air rises. Electrical and optical connectors are sometimes cooled by such airflow, depending on the configuration. 
     Cabinets including electronics that are cooled in this manner exhibit a significant caloric rise from bottom to top as the circulated air heats draws heat from each of the electronics in its path. Notably, the distance the air travels vertically through a tall cabinet significantly reduces the cooling efficiency of the upper electronics. Moreover, the cooling efficiency drops further due to the pressure drop from the bottom to the top of the cabinet. 
     In addition, such a cooling approach is often complex and expensive. Air conditioning may be needed to cool the air before it enters the cabinet. If the heat rise of the circulated air up through the cabinet is large, intercooler assemblies may be placed between electronics assemblies to extract heat from the vertically directed air between each assembly. Intercooler assemblies sometimes include a refrigerant or a liquid such as water to aid in extracting heat from the air passing through the intercooler assembly. Such approaches increase the heat generated by the cabinet, further reducing the power usage efficiency (PUE) of the unit. 
     Connectors, including backplane connectors interfacing electrical and optical signals into a card cage assembly including the circuit boards, also generate a significant source of heat during operation. Both wired and optical connectors can generate between 2 to 10 Watts of heat each in some configurations, which cumulative heat significantly increases the temperature within the cabinets and also the ambient. This heat generated by the connectors is not typically efficiently cooled or expelled from the cabinet because the connectors are not located in the cooling envelope of the air flow. While air flow may be provided across the circuit boards, the connectors extending through the backplanes interfacing with the circuit boards significantly extend behind the backplane and the card cage assembly, and may generate heat in a space or cavity defined between the backplane and the cabinet rear wall, or are exposed to the ambient. 
     What is needed is a system and method that addresses these issues and other issues that will become apparent in reading below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates an electronics system with transverse cooling; 
         FIG. 2A  s an exploded view of a blower assembly that can be used in the electronics systems of  FIG. 1 ; 
         FIG. 2B  illustrates an exploded view of a fan assembly that can be used in the blower assembly of  FIG. 2A ; 
         FIG. 3  illustrates an electronics system with an alternate transverse cooling approach; 
         FIG. 4  illustrates an electronics system with yet another transverse cooling approach; 
         FIG. 5  illustrates an electronics system with yet another transverse cooling approach; 
         FIG. 6  illustrates an electronics system with yet another transverse cooling approach; 
         FIG. 7  illustrates an electronics system with yet another transverse cooling approach; 
         FIG. 8  illustrates an electronics system with yet another transverse cooling approach; 
         FIG. 9  illustrates an electronics system with yet another transverse cooling approach; 
         FIG. 10  illustrates one example embodiment of the system of  FIG. 5 ; 
         FIG. 11  depicts a system diagram of the cooling system including a map of the circulated cooling fluid; 
         FIG. 12  depicts an exploded view of one cabinet to illustrate the vertically positioned intercooler, the chassis backplane cooling coils, and the power supply cooling coils and the various control valves; 
         FIGS. 13 and 14  illustrate air flow through an electronics system comprising four electronics cabinets, for two different ambient conditions, whereby the electronics system is room neutral such that the ambient temperature is not increased during operation of the electronics system; 
         FIG. 15  illustrates an embodiment of a multi-cabinet electronics system with transverse cooling; 
         FIGS. 16 and 17  illustrate example embodiments of larger multi-cabinet electronics systems with transverse cooling; 
         FIG. 18  illustrates an enlarged view of the heat pipe fingers shown in  FIG. 11 , each extending from the cooling pipe to backplane connectors; 
         FIG. 19  is a perspective view of one clip connector secured about an optical connector, and including a heat pipe drawing heat from the optical connector for routing to a cold junction of a cooling system; 
         FIG. 20A  is a perspective view of the clip connector secured about the optical connector,  FIG. 20B  is a perspective view of the rotated clip connector of  FIG. 20A , and  FIG. 20C  is an opposite side perspective view of the clip connector of  FIG. 20A ; 
         FIGS. 21A ,  21 B and  21 C are views of the clip connector; 
         FIG. 22A  is a perspective view of a left hand heat pipe attached to a cold junction bracket including a thermal filler,  FIG. 22B  is a side view of the heat pipe and cold junction bracket of  FIG. 22A , and  FIG. 22C  is a top view of the heat pipe and cold junction bracket of  FIG. 22A ; 
         FIG. 23A  is a side view of the heat pipe of  FIG. 22A , and  FIG. 23B  is another view of the heat pipe of  FIG. 22A ; 
         FIG. 24A  is a perspective view of a left hand heat pipe attached to a cold junction bracket including a thermal filler,  FIG. 24B  is a side view of the heat pipe and cold junction bracket of  FIG. 24A , and  FIG. 24C  is a top view of the heat pipe and cold junction bracket of  FIG. 24A ; and 
         FIG. 25A  is a side view of the heat pipe of  FIG. 24A , and  FIG. 25B  is another view of the heat pipe of  FIG. 24A . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention. 
       FIGS. 1-9  depict various embodiments of room neutral electronics systems according to preferred embodiments of the invention. 
     An electronics system with transverse cooling is shown in  FIG. 1 . In electronics system  100  of  FIG. 1 , a blower system  102  blows air horizontally across electronics assemblies positioned in cabinets  104  and  106 . In the example shown, each cabinet includes three electronics chassis  108 . Each electronics chassis  108  includes one or more electronics assemblies (not shown) oriented substantially horizontally in chassis  108 . In addition, each chassis  108  and each cabinet  104  is open to the first and second side to the extent necessary to receive air and direct that air across each of the plurality of electronics assemblies. 
     In the embodiment shown in  FIG. 1 , blower system  102  is positioned adjacent to the first side of the first cabinet and the second cabinet is positioned on the opposite side of the first cabinet. The electronics assemblies are cooled by actuating the blower system such that blower system  102  directs air into the first cabinet. The air flows substantially horizontally through the side of the first cabinet  104  and across each of the plurality of electronics assemblies within the first cabinet  104  before entering the second cabinet  106  and flowing substantially horizontally across each of the plurality of electronics assemblies of the second cabinet  106  before exiting the second cabinet  106 . 
     In another embodiment, electronics assemblies are cooled by actuating the blower system such that blower system  102  draws air from the first cabinet. The air flows substantially horizontally through the side of the second cabinet  106  and across each of the plurality of electronics assemblies within the second cabinet  106  before entering the first cabinet  104  and flowing substantially horizontally across each of the plurality of electronics assemblies of the first cabinet  104 . 
     A blower system  102  is shown in  FIG. 2A . In the blower system of  FIG. 2A , one or more blower assemblies  110  are positioned in a frame assembly  112 . In the embodiment shown in  FIG. 2A , each blower assembly  110  includes three blowers  120  stacked vertically. A power unit  114  is mounted under blower assembly  110 . In one embodiment, blower system also includes a side panel inlet/exhaust  116  used to prevent objects from entering blower assembly  110  and a frame joiner  118  used to connect blower system  102  to a respective cabinet. 
       FIG. 2B  provides an exploded view of one embodiment of a blower  120  that can be mounted in blower assembly  110 . Blower  120  includes a blower frame  122 , a fan  124 , a cover  126  and a grill  128 . In one embodiment, blower  120  is designed to be hot-swappable and is wired to indicate failure. 
     Another example electronics system with transverse cooling is shown in  FIG. 3 . In electronics system  130  of  FIG. 3 , a blower system  102  blows air horizontally across electronics assemblies positioned in cabinets  104  and  106 . Each electronics assembly is oriented substantially horizontally in cabinet  104  and  106 , as shown in  FIG. 9  which will be described in more detail shortly. In addition, each cabinet  104  and  106  is open to the first and second side to the extent necessary to receive air and direct that air across each of the plurality of electronics assemblies. An intercooler  132  is positioned between the first cabinet  104  and the second cabinet  106  and is configured to cool air as it passes through intercooler  132  before entering the next cabinet  106 . Intercooler  132 , as implemented and described in many embodiments of the invention hereafter, is preferably a coiled assembly configured to draw heat from air circulated therethrough into a fluid circulated through the coiled assembly, as will be discussed further in regards to  FIGS. 11-14 . 
     In the embodiment shown in  FIG. 3 , blower system  102  is positioned adjacent to the first side of the first cabinet  104  and the second cabinet is positioned on the opposite side of the first cabinet. The electronics assemblies are cooled by actuating the blower system such that blower system  102  directs air into the first cabinet. The air flows substantially horizontally through the side of the first cabinet  104  and across each of the plurality of electronics assemblies within the first cabinet  1046  before entering intercooler  132 . The air is cooled in intercooler  132  and then passes into the second cabinet  106 , flowing substantially horizontally across each of the plurality of electronics assemblies of the second cabinet  106  before exiting the second cabinet  106 . 
     In another embodiment, electronics assemblies in each cabinet  104  and  106  of  FIG. 3  are cooled by actuating the blower system such that blower system  102  draws air from the first cabinet. The air flows substantially horizontally through the side of the second cabinet  106  and across each of the plurality of electronics assemblies within the second cabinet  106  before entering intercooler  132 . The air is cooled in intercooler  132  and then passes into the first cabinet  104 , flowing substantially horizontally across each of the plurality of electronics assemblies of the first cabinet  104 , before being drawn into blower  102 . 
     Another example electronics system with transverse cooling is shown in  FIG. 4 . In electronics system  140  of  FIG. 4 , a blower system  102  blows air horizontally across electronics assemblies positioned in cabinets  104  and  106 . Each electronics assembly is oriented substantially horizontally in respective cabinet  104  and  106 . In addition, each cabinet  104  and  106  is open to the first and second side to the extent necessary to receive air and direct that air across each of the plurality of electronics assemblies. An intercooler  132  inserted between the first cabinet  104  and second cabinet  106  and is configured to cool air as it passes through intercooler  132  before entering the next cabinet  106 . A second intercooler  132  is configured to cool the air exiting cabinet  106 . 
     In the embodiment shown in  FIG. 4 , blower system  102  is positioned adjacent to the first side of the first cabinet and the second cabinet is positioned on the opposite side of intercooler  132 . The electronics assemblies are cooled by actuating the blower system such that blower system  102  directs air into the first cabinet  104 . The air flows substantially horizontally through the side of the first cabinet  104  and across each of the plurality of electronics assemblies within the first cabinet  104  before entering intercooler  132 . The air is cooled in intercooler  132  and then passes into the second cabinet  106 , flowing substantially horizontally across each of the plurality of electronics assemblies of the second cabinet  106  before exiting the second cabinet and entering intercooler  132 . 
     In another embodiment, electronics assemblies in each cabinet  104  and  106  of  FIG. 4  are cooled by actuating the blower system such that blower system  102  draws air from the first cabinet  104 . The air is drawn through intercooler  132 . The air then flow substantially horizontally through the side of the second cabinet  106  and across each of the plurality of electronics assemblies within the second cabinet  106  before entering intercooler  132 . The air is cooled in intercooler  132  and then passes into the first cabinet  104 , flowing substantially horizontally across each of the plurality of electronics assemblies of the first cabinet  104  before being drawn into blower  102 . 
     Another example electronics system with transverse cooling is shown in  FIG. 5 . In electronics system  150  of  FIG. 5 , a blower system  102  blows air horizontally across electronics assemblies positioned in cabinets  104  and  106 . Each electronics assembly is oriented substantially horizontally in the respective cabinet  104  and  106 . In addition, each cabinet  104  and  106  is open to the first and second side to the extent necessary to receive air and direct that air across each of the plurality of electronics assemblies. An intercooler  132  inserted between blower system  102  and cabinet  104  cools air as it passes through intercooler  132 . An intercooler  132  inserted between the first cabinet  104  and the second cabinet  106  cools air as it passes through intercooler  132  before entering the next cabinet  106 . 
     In the embodiment shown in  FIG. 5 , intercooler  132  is located between blower system  102  and cabinet  104 . The electronics assemblies in cabinet  104  are cooled by actuating the blower system such that blower system  102  directs air through intercooler  132  into the first cabinet. The air flows substantially horizontally through the side of the first cabinet  104  and across each of the plurality of electronics assemblies within the first cabinet  104  before entering intercooler  132 . The air is cooled in intercooler  132  and then passes into the second cabinet  106 , flowing substantially horizontally across each of the plurality of electronics assemblies of the second cabinet  106  before exiting the second cabinet. 
     In another embodiment, electronics assemblies in each cabinet  104  of  FIG. 5  are cooled by actuating the blower system such that blower system  102  draws air through intercooler  132  from the first cabinet  104 . The air is drawn initially through intercooler  132  from cabinet  106 . The air through cabinet  106  flows substantially horizontally through the side of the second cabinet  106  and across each of the plurality of electronics assemblies within the second cabinet  106  before entering intercooler  132 . The air is cooled in intercooler  132  and then passes into the first cabinet  104 , flowing substantially horizontally across each of the plurality of electronics assemblies of the first cabinet  104 , before being drawn into blower  102 . 
     Another example electronics system with transverse cooling is shown in  FIG. 6 . In electronics system  160  of  FIG. 6 , an additional intercooler  132  is added to system  160  of  FIG. 5 . In one embodiment, blower system  102  blows air horizontally across electronics assemblies positioned in cabinets  104  and  106 . Each electronics assembly is oriented substantially horizontally in respective cabinet  104  and  106 . In addition, each cabinet  104  and  106  is open to the first and second side to the extent necessary to receive air and direct that air across each of the plurality of electronics assemblies. An intercooler  1321  inserted between blower system  102  and cabinet  104  cools air as it passes through intercooler  132 . An intercooler  132  inserted between the first cabinet  104  and second cabinet  106  cools air as it passes through intercooler  132  before entering the next cabinet  106 . 
     In the embodiment shown in  FIG. 6 , the third intercooler  132  is added to one side of cabinet  106 . In one such embodiment, air blown through cabinet  106  passes through third intercooler  132  before being vented to the room 
     In another embodiment, electronics assemblies in each cabinet  104  and  106  of  FIG. 6  are cooled by actuating the blower system such that blower system  102  draws air through intercooler  132  from the first cabinet  104 . In such an embodiment, the third intercooler  132  cools the air before passing it on to cabinet  106 . 
     Another example electronics system with transverse cooling is shown in  FIG. 7 . In electronics system  170  of  FIG. 7 , a blower system  102  blows air horizontally across electronics assemblies positioned in cabinets  104  and  106 . Each electronics assembly is oriented substantially horizontally in respective cabinet  104  and  106 . In addition, each cabinet  104  and  106  is open to the first and second side to the extent necessary to receive air and direct that air across each of the plurality of electronics assemblies. An intercooler  132  mounted on the other side of cabinet  106  cools the air exiting cabinet  106 . 
     In the embodiment shown in  FIG. 7 , blower system  102  is positioned adjacent to the first side of the first cabinet, and the second cabinet is positioned on the opposite side of the first cabinet. The electronics assemblies are cooled by actuating the blower system such that blower system  102  directs air into the first cabinet  104 . The air flows substantially horizontally through the side of the first cabinet  104  and across each of the plurality of electronics assemblies within the first cabinet  104  before entering cabinet  106  The air flows substantially horizontally across each of the plurality of electronics assemblies of the second cabinet  106  before exiting the second cabinet and entering intercooler  132 . 
     In another embodiment, electronics assemblies in each cabinet  104  and  106  of  FIG. 7  are cooled by actuating the blower system such that blower system  102  draws air from the first cabinet  104 . The air is drawn through adjacent intercooler  132 . The air then flow substantially horizontally through the side of the second cabinet  106  and across each of the plurality of electronics assemblies within the second cabinet  106  before passing into the first cabinet  104 . The air then flows substantially horizontally across each of the plurality of electronics assemblies of the first cabinet  104 , before being drawn into blower  102 . 
     Another example electronics system with transverse cooling is shown in  FIG. 8 . In electronics system  180  of  FIG. 8 , an intercooler  132  is placed in between blower  102  and cabinet  104  of  FIG. 7 . 
     In the embodiment shown in  FIG. 8 , intercooler  132  is placed between blower system  102  and first cabinet  104 . The electronics assemblies are cooled by actuating the blower system such that blower system  102  directs air through intercooler  132  and into the first cabinet  104 . The air flows substantially horizontally through the side of the first cabinet  104  and across each of the plurality of electronics assemblies within the first cabinet  104  before entering cabinet  106 . The air flows substantially horizontally across each of the plurality of electronics assemblies of the second cabinet  106  before exiting the second cabinet and entering adjacent intercooler  132 . 
     In another embodiment, electronics assemblies in each cabinet  104  and  106  of  FIG. 8  are cooled by actuating the blower system such that blower system  102  draws air through intercooler  132  from the first cabinet  104 . The air is drawn through adjacent intercooler  132 , flowing substantially horizontally through the side of the second cabinet  106 . 2  and across each of the plurality of electronics assemblies within the second cabinet  106  before passing into the first cabinet  104 . The air then flows substantially horizontally across each of the plurality of electronics assemblies of the first cabinet  104 , before being drawn through intercooler  132  and into blower  102 . 
     Another example electronics system with transverse cooling is shown in  FIG. 9 . In electronics system  190  of  FIG. 9 , a blower system  102  blows air horizontally across electronics assemblies  192  positioned in respective chassis  103  in each of cabinets  104  and  106 . Each electronics assembly  192  is oriented substantially horizontally in its chassis  103  in cabinet  104  and  106 . In addition, each cabinet  104  is open to the first and second side to the extent necessary to receive air and direct that air across each of the plurality of electronics assemblies. A second blower system  102  mounted on the other side of cabinet  106  draws air from cabinet  106 . 
     In another embodiment, electronics assemblies in each cabinet  104  and  106  of  FIG. 9  are cooled by actuating both blower systems  102  such that the first blower system  102  draws air from the first cabinet  104  while the second blower system  102  blows air into cabinet  106 . The air flows substantially horizontally through the side of the second cabinet  106  and across each of the plurality of electronics assemblies within the second cabinet  106  before passing into the first cabinet  104 . The air then flows substantially horizontally across each of the plurality of electronics assemblies of the first cabinet  104 , before being drawn into first blower  102 . 
     A more detailed example of electronics system  150  of  FIG. 5  is shown in  FIG. 10 . In electronics system  150  of  FIG. 10 , blower system  102  blows air horizontally across each electronics assembly  192  horizontally positioned in respective chassis  103  of cabinets  104  and  106 . Each cabinet  104  and  106  has open first and second sides configured to receive and direct cooled air horizontally across each of the plurality of electronic assemblies  192 , and expel the heated air. The first intercooler  132  is shown inserted between blower system  102  and first cabinet  104  and cools air as it passes air from the blower system  102  through first intercooler  132 . The second intercooler  132  inserted between the first cabinet  104  and second cabinet  106  cools air as it passes through the second intercooler  132  before entering the next cabinet  106 . 
     In another embodiment, electronic assemblies  192  in each cabinet  104  and  106  of  FIG. 10  are cooled by actuating the blower system such that blower system  102  draws air through the first intercooler  132  from the first cabinet  104 . The air is drawn initially through the second intercooler cabinet  106  and the second intercooler  132 . The air through cabinet  106  flows substantially horizontally through the side of the second cabinet  106  and across each of the plurality of electronic assemblies  192  within the second cabinet  106  before entering the second intercooler  132 . The air is cooled in the second intercooler  132  and then passes into the first cabinet  104 , flowing substantially horizontally across each of the plurality of electronic assemblies  192  of the first cabinet  104 , before being drawn into blower  102 . 
     Advantageously, by directing air horizontally across electronics assemblies  192  mounted horizontally in the respective cabinets, the invention takes advantage of the decreased path length of air flow across the cabinets, such that the temperature gradient is reduced across the electronics assemblies  192  resulting in a higher efficiency cooling system. Further, the pressure drop of the cooing air from side to side is reduced, allowing the implementation of less powerful fans and less expensive fans in blower  102  to achieve the desired cooling. The cooling system is configured such that the electronics system is room neutral, meaning the temperature of the air expelled from the cooled system is the same as the ambient air drawn into the cooling system, as will now be described in more detail. 
     Referring to  FIGS. 11-12 ,  FIG. 11  illustrates a system diagram of the fluid cooling system at  200 . System  200  is seen to comprise a cooling fluid inlet  202  feeding main fluid loop  203 , a fluid outlet  204 , and a variably fluid control valve  206  associated with each cabinet and electronically controlled by a control signal  208  from a process controller  210 . Each control valve  206  controls fluid flow to main fluid loop  203  associated with a cabinet, whereby valve  232  controls the portion of fluid flow through cooling loop  205 , known as a manifold, and the power supply water coil  214 , whereby the balance of fluid flow from main fluid loop  203  flows through intercooler  132 . The coil of the intercooler  132  has an inlet  220  coupled to the main fluid loop  203 , and an outlet  222  feeding fluid outlet  204 . The power supply coil  214  has an inlet  228  and outlet  230  also feeding fluid outlet  204 . The chassis backplanes  212  each have a plurality of left hand heat pipe fingers  224  and right hand heat pipe fingers  226  each physically and thermally coupled to the cooling loop  205 . The cooling loop  205  forms a cold junction  252  for sinking heat from the optical connectors  250  via the heat pipe fingers. The flow of cooling fluid flowing proximate the cold junctions  252  of the heat pipe fingers  224  and  226  sinks heat from the chassis backplane connectors  252  via the heat pipe fingers, as will be further described shortly in reference to  FIGS. 18-24 . 
       FIG. 12  illustrates an exploded view one cabinet having a respective intercooler  132 , chassis backplanes  224  supporting the plurality of electronic assemblies  192 , and the associated power supply unit  114  partitioned into  2  parts as shown. Collectively, the coils of these subsystems draw all heat generated by the electronics systems  192  and the power supply unit  114  such that the system is room neutral. 
       FIGS. 13 and 14  depict a pair of serially positioned electronics systems  160  of  FIG. 6 , in two different room neutral conditions. In the example embodiment shown in  FIG. 13 , the air entering blower system  102  is at 22° C., sea level, and intercoolers  132 , chassis backplane coils  212 , and power supply coils  214  each operate such that the collective systems  160  expel air to the ambient at 22° C., such that the complete system is room neutral. As shown, the temperature of the cooling fluid provided to each coil is 45° F., and the associated return fluid temperature of each coil and the fluid flow rate is shown. In the example shown in  FIG. 14 , the ambient room temperature is 32° C., sea level, and thus the fluid flow rates to the various coils are increased to maintain a room neutral system, as shown. 
     In the examples shown in  FIGS. 13 and 14 , there is no intercooler  132  to the right of the right blower  102 , because there is an intercooler  132  to the left of the right blower  102 , although the intercooler associated with the right blower  102  could be positioned to the right thereof if desired. 
     In the examples shown in  FIGS. 13 and 14 , the power supply coils  214  remove heat generated by the respective power supplies  114  such that the power supplies  114  don&#39;t contribute heat to the heat generated by electronics assemblies  192  above. Advantageously, this modular cooling design is configured such that the electronics assemblies  192  are thermally isolated from the power supplies  114 . 
     In the various embodiments, a temperature sensor is positioned on or proximate on each electronics assembly  192  and used to determine the adequate flow of cooling fluid into associated intercooler  132 . The controller  210  variably and responsively controls the respective valves  206  and  232  such that the thermal gradients of the respective cooling coils achieve the desired cooling. In one embodiment, the respective system may apply direct enough cooling fluid to maintain the temperature of the air exiting each intercooler at the temperature of the air going into the previous component. In another embodiment, the respective system may apply only enough water to maintain the temperature of the air exiting one or more intercoolers at a predetermined temperature higher or lower that the temperature of the air going into the previous component. 
     One advantage of transverse cooling is that the heat added by each cabinet is extracted soon after the air leaves the cabinet. In the examples shown in  FIGS. 3 ,  4 ,  5 ,  6  and  11 - 13 , the heat is extracted by an intercooler  132  as soon as the air leaves the respective cabinet. In the examples shown in  FIGS. 7 and 8 , the heat is extracted by an intercooler  132  as soon as the air leaves the second cabinet  106 . As a result, the air exiting from each system is at or around the same temperature that it was when entering system, thus room neutral. The air leaving the system can, therefore, be used to cool the next cabinet to realize a significantly large electronics system. 
     An example of a larger-scaled room neutral electronics system  300  comprising a single row of cabinets is shown in  FIG. 15 , with various components labeled for illustration. A main cooling fluid supply line  302  is shown which feeds each cabinet water inlet  202  is shown. 
     An even larger scaled electronics system  400  with multiple rows of cabinets is shown in  FIG. 16 . In the example shown in  FIG. 16 , the computer cabinets, i.e. cabinets  104  and  106 , are placed side-by-side to form a row of cabinets  402 , and the rows of cabinets  402  are arranged to form an array of cabinets  404 . Air is directed into a first one of the cabinets  406  in each row and flows from cabinet to cabinet down the row. In the example shown in  FIG. 16 , a blower intercooler combination as is shown in  FIGS. 5 ,  6 ,  8 ,  10 ,  11 ,  12  and  13  is used to cool air received from an air intake  408  before directing the air into the row of cabinets. Water lines  302  supply water to each computer cabinet and are controlled to cool air leaving each computer cabinet to approximately the same temperature it had when entering cabinet. Cable trays  410  carry cables connecting cabinets to cabinets in other rows. Cable access openings  412  and cable exit ports  414  are used to direct and protect cables passing between rows. Air mover racks are shown at  416 . 
     In one embodiment, an air curtain or ducting forms an air redirector  420  used to move air flowing from one row of cabinets  402  to the next row of cabinets  402 , such as in a serpentine arrangement as shown in  FIG. 17 . In one embodiment, the systems include N+1 blower systems  102  for system configurations of N cabinets, where N is less than or equal to 6. One of the blower systems is configured as an exhaust blower cabinet. 
     In another embodiment, the systems include N+1 blower systems  102  for system configurations of N cabinets, where there are N cabinets in a row and where N is greater than or equal to 10. In configurations where an exhaust blower cabinet is needed, N+2 blower systems are used. 
     In one embodiment, the systems include sensors for monitoring system thermal conditions. In one such embodiment, the systems monitor ambient air temperature, ambient relative humidity, ambient dew point, blower status, air velocity and temperature of the air exiting intercooler assembly  132 , water coil inlet water temperature, water pressure differential across the water coil, water coil outlet air temperature and water detection both in the pre-conditioner and in computer cabinet. In one embodiment, the controls include front end rectifier power good indication. 
     In one embodiment, the systems use water valves to control coil water flow and air exhaust temperature, to precondition incoming air and to maintain room neutral exhaust temperatures. 
     In one embodiment, the controllers  210  vary blower cabinet fan speed as needed. In one such embodiment, the systems increase fan speed upon fan failure to maintain air velocity. In another embodiment, the systems increase fan speed to maintain chip temperatures in electronics assemblies  192 . If chip temperature exceeds a set value, the respective water valve is opened to bring the chip temperature down. If that doesn&#39;t work by itself, then the fan speed can be increased to 100% full speed. 
     The above described transverse cooling system and method is advantageous since it reuses air as that air passes through each cabinet. The increased cross-sectional area and the decreased pressure drop means that this method is a more efficient way of removing heat from the system. The increased cross-sectional area means that more fans can be placed in parallel. This, in turn, reduces the cost of the fans, as industry standard fans can be used instead of custom fans. It also reduces the effects of loss of a fan in blower system  102 . 
     In addition, since, in some embodiments, air exiting each cabinet is around the same temperature as entering the cabinet, similar cabinets  104  should exhibit similar thermal profiles and have similar energy utilization. That is, the cooling system is room neutral. Unconditioned and unfiltered air can be used. 
     Transverse cooling shows a dramatic increase in cooling efficiency. In one example embodiment, cooling energy dropped to 3% of total system power. This approach eliminates the need for conditioning and filtering air in the room in which systems are placed, relaxing computer room environmental requirements. The increased cross-sectional area of air flow reduces the effect of failures in any one fan, or in any one component of the cooling system, increasing system reliability. 
     Referring now to  FIG. 18 , there is shown an enlarged view of the chassis backplanes  212  of  FIG. 11  having the associated connectors  250  disposed therethrough and configured to receive electrical and/or optical cables, commonly known as vertical CXP connectors. A cooling system  300  according to a preferred embodiment of the invention is shown, including an associated heat sink finger comprising heat pipe finger  224  and  226  physically and thermally coupled to the each of the respective CXP connectors  250 , such as via a clip or bracket as will be described shortly, and to the cooling loop  205  via the cold junctions  252 . Each heat pipe finger  224  and  226  is coupled to the respective connectors  250  and is configured to sink heat therefrom, and transfer the sinked heat to the cold junctions  252  of cooling loop  205  or manifold as previously described with reference to  FIG. 11 . The heat drawn to the cold junctions  252  is then sinked/transferred to the fluid flowing through the cooling loop  205  and extracted from the system. In the embodiment as shown, each heat pipe finger is coupled to five connectors  250 , although more or less connectors can be coupled to a single heat pipe finger depending on the thermal design. 
     Advantageously, the connector cooling system  300  is configured to keep the case temperature of the connectors  250  less than 70 C with the connectors generating 4 Watts, allowing the overall system to remain room neutral within +/−10%. The connector temperature may be maintained at a lower temperature, and the connectors may generate between 2-10 Watts, depending on the connector and application. The heat pipe fingers, connector clips, and cold junction couplers do not interfere with electrical or optical cables routed to the connectors  250 . The cooling system  300  is passive and does not require power, control or monitor additional hardware. The cooling system does not create main cabinet cooling system air leaks, and is separate from the air flow envelope, such as the transverse cooling system previously described. The cooling system takes advantage of the cooling fluid, such as water, brought to every cabinet. One goal is to allow as high temperature of the cooling fluid as possible, such as 70 F (21 C). Cooling system  300  effectively maintains the connector temperature at  70 F when operating with this cooling fluid temperature. 
     Referring to  FIG. 19 , there is shown an enlarged view of one active optical connector (AOC)  250  physically and thermally coupled to a heat pipe finger  224  via a CXP clip connector  302 .  FIGS. 20A ,  20 B and  20 C show the CXP clip connector  302  secured about the AOC  250  without the heat pipe finger  224 , and  FIGS. 21A ,  21 B and  21 C show the CXP clip connector  302  alone. Connector  302  is comprised of a thermally conductive material, such as copper or an alloy, and comprises an integral L-shaped member  303  having a planar side member  304  and a base member  306 . A bracket  307  having a planar top member  308 , planar bottom member  309  and a joining intermediate planar side wall  311  having a plurality of inwardly extending spring fingers  312 , is physically and thermally joined to member  303 . The planar opposing major surfaces of member  304  and side wall  311  are physically and thermally joined to have excellent heat transfer characteristics, and may be joined via fasteners disposed through openings  316 , or bonding such as brazing. The bracket base member  309  and top member  308  each form an opposing spring that are slightly resilient and configured to securely snap fit about and engage the back shell of the AOC connector  250 , whereby the spring fingers  312  physically and thermally engages the opposing major side wall of the connector  250  back shell. The tension of the spring base member  309  and top member  308  provides a force that secures the connector  302  to the AOC  250  back shell, such that base member  308 , top member  309  and intermediate side wall  311 /side member  304  efficiently sink heat from the back shell of connector  250  during operation of the connector  250 . An integral clip  310  extends from base member  306  and is configured to physically and thermally receive the associated heat pipe finger  224 , whereby the heat in the AOC connector  250  is sunk by the connector  302  to the heat pipe finger  224  via clip  310 . Side member  304  is comprised of a planar heat spreader, such as a copper plate of suitable thickness, and is configured to efficiently sink heat from the connector  250  back shell via bracket  311  including the spring fingers  312 . Advantageously, the Case to Pipe Resistance of the CXP connector  302  is about 4 C/W. The Case is the AOC  250  back shell temperature, and the Pipe is the temperature of the heat pipe  224  on the cold junction side of the clip connector  302 . 
     Referring now to  FIGS. 22A ,  22 B and  22 C there is shown one left hand heat pipe finger  224  thermally and physically coupled to, and received by, a cold junction connector  350 . The cold junction connector  350  has an opening  352  securely receiving a proximal end  354  of the heat pipe finger  224 . A thermal filler material  356  is secured to an end face  358  of the connector  350 , and is configured to be interposed between the connector  350  and the cold junction  252  of cooling loop  205 . A preferred thermal filler material  356  is TFLEX 640-DC1 available from Laird Tech, although other suitable thermal filler materials, such as thermal grease, are suitable as well. 
       FIGS. 23A and 23B  show views of the heat pipe finger  224  alone. A heat pipe is a heat-transfer device that combines the principles of both thermal conductivity and phase transition to efficiently manage the transfer of heat between two solid interfaces. At the hot interface within a heat pipe, which is typically at a very low pressure, a liquid in contact with a thermally conductive solid surface turns into a vapor by absorbing heat from that surface. The vapor then travels along the heat pipe to the cold interface, condenses back into a liquid, releasing the latent heat. The liquid then returns to the hot interface through either capillary action or gravity action where it evaporates once more and repeats the cycle. In addition, the internal pressure of the heat pipe can be set or adjusted to facilitate the phase change depending on the demands of the working conditions of the thermally managed system. 
     A typical heat pipe consists of a sealed pipe or tube made of a material with high thermal conductivity such as copper or aluminum at both hot and cold ends. A vacuum pump is used to remove all air from the empty heat pipe, and then the pipe is filled with a fraction of a percent by volume of working fluid (or coolant) chosen to match the operating temperature. Alternatively, the pipe is heated until the fluid boils, and sealed while hot. Examples of such fluids include water, ethanol, acetone, sodium, or mercury. Due to the partial vacuum that is near or below the vapor pressure of the fluid, some of the fluid will be in the liquid phase and some will be in the gas phase. The use of a vacuum eliminates the need for the working gas to diffuse through any other gas and so the bulk transfer of the vapor to the cold end of the heat pipe is at the speed of the moving molecules. In this sense, the only practical limit to the rate of heat transfer is the speed with which the gas can be condensed to a liquid at the cold end. 
     Inside the pipe&#39;s walls, an optional wick structure exerts a capillary pressure on the liquid phase of the working fluid. This is typically a sintered metal powder or a series of grooves parallel to the pipe axis, but it may be any material capable of exerting capillary pressure on the condensed liquid to wick it back to the heated end. The heat pipe may not need a wick structure if gravity or some other source of acceleration is sufficient to overcome surface tension and cause the condensed liquid to flow back to the heated end. 
     Referring now to  FIGS. 24A ,  24 B and  24 C there is shown one right hand heat pipe finger  226  thermally and physically coupled to, and received by, a cold junction connector  350 . The cold junction connector  350  has an opening  352  securely receiving a proximal end  354  of the heat pipe finger  226 . A thermal filler material  356  is secured to an end face  358  of the connector  350 , and is configured to be interposed between the connector  350  and the cold junction  252  of cooling loop  205 . A preferred thermal filler material  356  is TFLEX 640-DC1 available from Laird Tech, although other suitable thermal filler materials, such as thermal grease, are suitable as well.  FIGS. 25A and 25B  show views of the heat pipe finger  226  alone. 
     Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement which is calculated to achieve the same purpose may be substituted for the specific embodiment shown. This application is intended to cover any adaptations or variations of the present invention. Therefore, it is intended that this invention be limited only by the claims and the equivalents thereof.