Abstract:
A multizone variable damper for air passageways having a plurality of damper zones, a plurality of opposed blades that are rotatable about a horizontal axis, a pair of blades of the plurality of blades being provided in each zone of the plurality of damper zones, and an actuator for each pair of blades, each actuator being configured to independently rotate each of the pairs of blades of the plurality of opposed blades so as to selectively and independently control a degree of openness of each of the pairs of blades of the plurality of opposed blades in each damper zone of the plurality of damper zones.

Description:
BACKGROUND 
       [0001]    1. Field of the Invention 
         [0002]    This invention relates to variable dampers that regulate air flow through passageways, such as grates. The dampers are positioned in or adjacent the passageways and have one or more members that selectively and variably block air passing through the passageways. 
         [0003]    2. Background of the Invention 
         [0004]    There are certain environments in which it may be desirable to regulate the air flow through a passageway such that different volumes of air are permitted to pass through different zones of the passageway. One such environment is a data center, and the subject passageway is an access floor grate panel in the data center, as discussed below. 
         [0005]    A typical data center includes multiple IT racks. The equipment supported by those racks, and the associated cables and other accessories, generate a relatively high amount of heat. Because of that heat, providing adequate cooling to IT racks in the data center is of paramount importance. Moreover, it is desirable that the IT racks be cooled as efficiently as possible, as the energy costs to cool IT racks may approach a large percentage of the energy costs to operate the data center. 
         [0006]    Data centers typically have a raised floor system, often called an access floor system. An access floor system is usually comprised of a continuous array of floor panels, arranged edge-to-edge, and supported above the sub-floor by support structure. The array of access floor panels usually extends wall-to-wall in the data centers. 
         [0007]    A plenum is formed between the sub-floor and the access floor panel array. Cables, wires, hoses, etc. are located in the plenum, and the plenum is also used as a conduit for cooling air. Often, one or more air conditioning units supply air to the plenum, and some of the access floor panels in the access floor panel array have grates. The cooling air passes through the grates into the data center. 
         [0008]    The access floor panels with grates are usually positioned immediately adjacent to IT racks, and may have vanes that direct the cooling air that passes through the grates toward the IT racks. 
         [0009]    A typical IT rack supports a variety of electronic equipment. The equipment is often unevenly distributed throughout the rack, including vertically. In that regard, an IT rack may have shelves, spaced vertically. Different equipment may be placed on the different individual shelves. 
         [0010]    Different IT equipment generates different amounts of heat. Thus, the heat generated by the equipment at one vertical height of an IT rack (e.g., on one shelf) may differ from the heat generated by the equipment at another vertical height of the same IT rack (e.g., on a different shelf). However, the prior art IT rack cooling apparatus does not take into account that difference in heat at the various heights. Rather, usually there are temperature sensors at various locations of an IT rack, and the volume of cooling air is determined for the whole rack based on the readings of those sensors. In fact, often the volume of cooling air for the entire rack is based on the highest sensed temperature in the IT rack. That is, the entire IT rack is subjected to the volume of cooling air necessary to cool the hottest area or zone in the rack, even the areas or zones of the rack that are already much cooler than the hottest area or zone. 
         [0011]    This results in inefficient cooling of the IT racks, because the cooling air is directed at the same volume to all areas of the IT rack based on the highest temperature in the rack, even to those areas that may need little, if any, cooling. More efficient and economical cooling would be achieved if larger amounts of cooling air are directed to the hottest areas of the IT racks, while lesser amounts of cooling air are directed to the other, cooler areas of the IT rack. Thus, in a data center, there is a need for cooling apparatus that directs different amounts of cooling air to different areas of or zones in the IT racks in the data center. 
       SUMMARY OF THE INVENTION 
       [0012]    The multizone variable damper of this invention addresses that need, as well as the need in other environments for apparatus that selectively regulates the flow of air in different zones of a passageway. 
         [0013]    A multizone variable damper according to one embodiment of this invention includes two or more air passageway zones defined by movable members, wherein the positions of the movable members determine the air passageway openings in each of the passageway zones. The movable members are movable relative to each other such that the sizes of the air passageway openings in the passageway zones can be varied relative to each other. This embodiment also includes actuators that move the movable members relative to each other. 
         [0014]    In certain embodiments, the movable members are pairs of opposed blades, with one of the pairs of opposed blades being located in each air passageway zone. The blades may extend lengthwise, and the air passageway zones may be aligned edge-to-edge widthwise. 
         [0015]    The actuators can be manual or “automatic.” The “automatic” actuators may move the movable blades based on predetermined conditions (e.g., time of day) or sensed conditions (e.g., temperature or pressure differential). 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  is a partial view of a data center that includes a multizone variable damper of this invention. 
           [0017]      FIG. 2  is a top view of one embodiment of this invention. 
           [0018]      FIG. 3  is a side view of the embodiment of this invention illustrated in  FIG. 2 . 
           [0019]      FIG. 4  is a schematic diagram of the multizone variable damper of  FIGS. 1-3  installed in an access floor panel array, with temperature sensors on the adjacent IT rack. 
           [0020]      FIG. 5  is a schematic diagram of the sensors, control unit and actuators. 
           [0021]      FIGS. 6 and 7  illustrate the multizone variable damper of  FIGS. 2 and 3 , in a data center, with the pairs of opposing blades in different positions. 
       
    
    
     DETAILED DESCRIPTION 
       [0022]    Before describing the multizone variable damper of this invention, one environment in which it may be utilized is first described. The environment is a data center that includes one or more IT racks. That environment is illustrated, in part, in  FIG. 1 . 
         [0023]    In  FIG. 1 , IT rack  30  is in a data room and positioned on and supported by access floor panel array  35 . Access floor array  35  is spaced above subfloor  34 . The space or plenum  70  between access floor panel array  35  and subfloor  34  functions as a conduit for air from an air conditioning unit (not shown). The access floor panel array  35  includes grate panel  32 , which is positioned immediately adjacent IT rack  30 . An access floor panel array in a data room will usually include multiple grate panels.  FIG. 1  illustrates one of those grate panels. Cooling air passes from plenum  70  through grate panel  32  to cool IT rack  30 . 
         [0024]    IT rack  30  supports a variety of IT equipment. The heat generated by the equipment supported by IT rack  30  may vary in different areas or zones of IT rack  30  for many reasons, including the following. First, different types of IT equipment generate different amounts of heat. Second, the equipment may be unevenly distributed in IT rack  30 , in all three dimensions, including vertically, laterally and longitudinally. Third, different units or assemblies of the equipment may operate at different times of the day. All of those factors may result in zones of different temperatures in IT rack  30  at any given time. For example, in  FIG. 1 , IT rack  30  may have vertical zones  31   a ,  31   b  and  31   c , from bottom to top, of different temperatures at a given time. In  FIG. 1 , those temperatures are: zone  31   a— 73°; zone  31   b— 75°; and zone  31   c— 71°. 
         [0025]    To achieve the most efficient and economical cooling of IT rack  30  when it has zones of different temperatures, such as zones  31   a ,  31   b  and  31   c , it is desirable to supply or direct different volumes of cooling air to the different zones, so that each zone is cooled by the minimum necessary amount of cooling air. Thus, taking  FIG. 1  as an example, for efficient and economical cooling, more cooling air should be directed to zone  31   b  than to zones  31   a  and  31   c , and more cooling air should be directed to zone  31   a  than to zone  31   c.    
         [0026]    This invention achieves that goal, as discussed in detail below. 
         [0027]    The embodiment of this invention illustrated in the Figures is multizone variable damper  10 . In  FIG. 1 , multizone variable damper  10  is positioned below grate panel  32  in access floor panel array  35 . 
         [0028]    Multizone variable damper  10  is illustrated in more detail in  FIGS. 2 and 3 . In particular,  FIG. 2  is a top view and  FIG. 3  is a side view of multizone variable damper  10 . 
         [0029]    In the embodiment illustrated in the Figures, the multizone variable damper  10  defines three zones: zones  21   a ,  21   b  and  21   c . The number of zones is not limited to three, but can be more than three zones and as few as two zones. 
         [0030]    The zones  21   a ,  21   b  and  21   e  are positioned such that air that passes through each zone is directed, by grate panel  32 , to a specific zone in IT rack  30 . In this embodiment, the air from zone  21   a  is directed to IT rack zone  31   a , the air from zone  21   b  is directed to IT rack zone  31   b , and the air from zone  21   c  is directed to IT rack zone  31   c . See  FIGS. 6 and 7 , discussed in more detail below. 
         [0031]    Also in the embodiment illustrated in the Figures, each zone has a pair of opposed blades that move relative to each other to control airflow through that zone. Specifically, opposed blades  30   a  are in zone  21   a , opposed blades  30   b  are in zone  21   b  and opposed blades  30   c  are in zone  21   c . The blades  30   a ,  30   b  and  30   c  can be made of any material that is capable of providing the structural rigidity required for a given application. Preferably, the blades  30   a ,  30   b  and  30   c  are made of metal. 
         [0032]    Opposed blades  30   a ,  30   b  and  30   c  extend the length of multizone variable damper  10 , and the zones  21   a ,  21   b  and  21   e  are located serially along the width of multizone variable damper  10 . 
         [0033]    As shown in  FIG. 3 , in this embodiment of the invention, each blade of blades  30   a ,  30   b  and  30   c  is rotatable about an axis. The blades are rotatable between the extreme positions of completely closed (see blades  30   a  in  FIG. 3 ) to completely open (see blades  30   c  in  FIG. 3 ) to all positions between those extreme positions. 
         [0034]    While the embodiment illustrated in the Figures utilizes pairs of opposed blades  30   a ,  30   b  and  30   c  to regulate the amount of air that passes through each zone  21   a ,  21   b  and  21   c , respectively, any other means for variably regulating air flow through zones  21   a ,  21   b  and  21   c  can be used in place of opposed blades  30   a ,  30   b  and  30   c , including single blades. However, one advantage of using a pair of opposed blades instead of a single blade is that the pair of opposed blades does not interfere with the directional nature of grate panel  32  if grate panel  32  is a directional grate. 
         [0035]    In this embodiment, the multizone variable damper  10  includes actuators  20   a ,  20   b  and  20   c , which are provided for each pair of opposed blades  30   a ,  30   b , and  30   c , respectively. The actuators  20   a ,  20   b  and  20   c  rotate the pairs of opposed blades  30   a ,  30   b  and  30   c  to their desired positions. The actuators  20   a ,  20   b  and  20   c  can either be manually operated or can be automatically operated. 
         [0036]    There is a wide variety of manual actuators that can be used to rotate the blades of pairs of opposed blades  30   a ,  30   b  and  30   c , including a lever (not shown) that is rotatable between fully closed and fully opened positions, and all positions between those two extremes. The lever is connected by a link or a series of links to a member that rotates the pair of blades. When the lever is in a first position, the rotatable member positions the pair of blades in the completely closed position. When the lever is rotated to a second position, the rotatable member is rotated to position the pair of blades in the completely open position. 
         [0037]    There is also a wide variety of “automatic” actuators that can be used to rotate the blades of pairs of opposed blades  30   a ,  30   b  and  30   c , including motors that rotate the blades in accordance with signals or instructions from a control unit. The control unit may instruct the movement of the blades based on a sensed condition, or a predetermined condition such as by the time. An example of a control unit that is responsive to a sensed condition is illustrated in  FIG. 5 . 
         [0038]    In  FIG. 5 , the temperatures from sensors  80   a ,  80   b  and  80   c  are communicated to control unit  110 . Based on that temperature data, control unit  110  instructs the actuators  20   a ,  20   b  and  20   c  to rotate the various blades of pairs of blades  30   a ,  30   b  and  30   e  as necessary to adjust the openings provided by the pairs of blades  30   a ,  30   b  and  30   c.    
         [0039]    In the embodiment illustrated by  FIG. 4 , the temperature sensors  80   a ,  80   b  and  80   c  are located in IT rack zones  31   a ,  31   b  and  31   c , respectively. Each sensor  80   a ,  80   b  and  80   c  can be a single sensor unit or multiple sensor units. In the embodiment illustrated in the  FIG. 4 , the temperature sensors  80   a ,  80   b  and  80   c  are single units located on the front face  100  of the IT rack  30 . However, the temperature sensors  80   a ,  80   b  and  80   c  can be placed at other positions in zones  31   a ,  31   b  and  31   c , for example, on the back face of IT rack  30  where the cooling air is exhausted. Further, if a sensor  80   a ,  80   b  and/or  80   c  includes more than one sensor unit, those sensor units can be positioned in different locations in the respective zones  31   a ,  31   b  and  31   c.    
         [0040]    The temperature data from sensors  80   a ,  80   b  and  80   c  is used to adjust the positions of the blades of pairs of blades  30   a ,  30   b  and  30   c  so that the minimal necessary cooling air is directed or supplied to the IT rack zones  31   a ,  31   b  and  31   c . Examples are discussed below, with reference to  FIGS. 6 and 7 . 
         [0041]    In  FIG. 6 , the temperature in IT rack zone  31   a  is 73°, the temperature in IT rack zone  31   b  is 75°, and the temperature in IT rack zone  31   c  is 71°. Those temperatures are communicated to control unit  110 , which instructs actuators  20   a ,  20   b  and  20   c  to place blades  30   a ,  30   b  and  30   c  in the positions illustrated in  FIG. 6 , which is that blades  30   a  are in a partially open state, blades  30   b  are in a fully opened state and blades  30   c  are in a completely closed state. This results in the highest airflow being directed to IT rack zone  31   a , a less amount of airflow being directed to IT rack zone  31   b , and little, if any, airflow being directed to IT rack zone  31   c.    
         [0042]    In  FIG. 7 , the temperature in IT rack zone  31   a  is 74°, the temperature in IT rack zone  31   b  is 73°, and the temperature in IT rack zone  31   c  is 71°. Accordingly, control unit  110  instructs actuators  20   a ,  20   b  and  20   c  to rotate blades  30   a  and  30   b  such that blades  30   a  and  30   b  are positioned to be partially open; however, the opening through blades  30   a  is greater than the opening through blades  30   b  because IT rack zone  30   a  is warmer than IT zone  31   b . Finally, the blades  30   e  are positioned in the completely closed position. 
         [0043]    As can be determined, blades  30   a ,  30   b  and  30   c  can be positioned relative to each other in any manner dictated by the respective temperatures in IT rack zones  31   a ,  31   b  and  31   c.    
         [0044]    As stated, in this embodiment, the control unit  110  controls the actuators  20   a ,  20   b  and  20   c  based on temperatures in the respective IT rack zones, zones  31   a ,  31   b  and  31   c . In other embodiments, the control unit  110  may receive and act on pressure differentials in the various zones, for example at the back face of the IT rack  30 , instead of the temperatures. 
         [0045]    Further, in other embodiments, each actuator  20   a ,  20   b  and  20   c  may be operated by a separate control unit dedicated to it. That is, instead of a single control unit  110 , there is a separate control unit for each actuator  20   a ,  20   b  and  20   c . Those individual control units receive information from the corresponding IT rack zones and provide instructions to the corresponding actuators. For example, an individual control unit for actuator  20   a  would receive the temperature data from sensor  80   a  and instruct actuator  20   a  accordingly, the control unit for actuator  20   b  would receive the temperature data from sensor  80   b  and instruct actuator  20   b  accordingly, and the control unit for actuator  20   c  would receive temperature data from sensor  80   c  and instruct actuator  20   c  accordingly. 
         [0046]    By providing three or more zones, the multizone variable damper  10  of this invention allows for precise cooling of the IT rack  30  based on sensed conditions along the height of the IT rack  30 . 
         [0047]    What has been described and illustrated herein are preferred embodiments of the invention along with some variations. The terms, descriptions and figures used herein are set forth by way of illustration only and are not meant as limitations. Those skilled in the art will recognize that many variations are possible within the spirit and scope of the invention, which is intended to be defined by the following claims—and their equivalents—in which all terms are meant in their broadest reasonable sense unless otherwise indicated.