Abstract:
A system for removing heat from heat load equipment including a re-circulating air handling unit for establishing an air curtain that flows up from and around the heat load equipment and one or more roof-mounted heat stratification housings disposed over the heat load equipment for receiving heat from the equipment. The heat generated from the equipment travels upwardly inside of and propelled by the air curtain. The heat stratification housing includes a plurality of heat transfer plates that extend between interior and exterior areas thereof. Water nozzles direct a spray on the heat transfer plates.

Description:
RELATED CASES 
       [0001]    Priority for this application is hereby claimed under 35 U.S.C. § 119(e) to commonly owned and co-pending U.S. Provisional Patent Application No. 61/031,816 filed on Feb. 27, 2008 and which is incorporated by reference herein in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates in general to a heat dissipation system, and more particularly, to a system for removing btu&#39;s generated from heat load equipment by means of a heat stratification technique. 
       BACKGROUND OF THE INVENTION 
       [0003]    Current environmental systems for high-density heat load applications collect the generated heat and discharge it externally. The heat is collected for mechanical rejection outside the building using, for example, chillers, cooling towers, piping and pumps. One of the major problems associated with existing systems is the substantial expense particularly in electrical usage for kilowatts per ton of cooling. At the present time there may be considered as basically two different types of systems. A first system is an all air system and a second system is a combination of rack cooling and an air system. 
         [0004]    The all air systems use maximum coverage and include fan powered boxes or VAV boxes throughout the room that are controlled by sensors to prevent stratification or hot spots. These all -air systems require large equipment, large duct work, fan-powered boxes, VAV boxes and associated controls. These systems are thus relatively complicated in design, require excessive maintenance and are costly to install and maintain. 
         [0005]    The combination rack cooling and air system uses enclosures that entrap the heat and send it outdoors via piping systems to reject the heat produced by the equipment. The air system cools the remainder of the room from floor to ceiling usually as per ISO design criteria. The rack cooling and air system surrounds the high-density heat load equipment in a cabinet usually maintained at 55° F. The rack cooling technique intakes room system air and exhausts hot air back into the primary HVAC system. The primary HVAC system then returns this additional heat as well as the heat load of the space. 
         [0006]    It is an object of the present invention to provide an improved heat dissipation system, one that is more efficient in its operation than existing systems, is more maintenance free and can be constructed at substantially reduced cost. 
       SUMMARY OF THE INVENTION 
       [0007]    To accomplish the foregoing and other advantages and features of the present invention there is provided a system that employs a heat stratification concept that includes one or more heat stratification housings. The heat stratification zone is for storing and the rejection of heat through the heat stratification housings. This is combined with an air-conditioning zone which is defined about the high-density heat load equipment. 
         [0008]    The heat stratification housings in accordance with the present invention reduce the electrical cost of rejecting BTU&#39;s from the facility. The heat rejection capabilities of the housings allow for a savings in electrical cost and the total required capacity of the HVAC system. This is possible in accordance with the present invention because the heat load is not returned to the cooling cycle. The system of the present invention also employs what is herein termed air curtains that surround the equipment with the primary HVAC system serving only the cubic footage that is not covered by the air curtains. This conditioning zone about the heat load equipment is considered as having a height on the order of the equipment height in which case the size of the primary HVAC system can be substantially reduced. Currently, the cubic footage of an HVAC system is calculated using the total cubic footage of the room from floor to ceiling. This results in greater sized systems and equipment which are not necessary in accordance with the present invention as the HVAC system is designed only for use in the conditioned zone. 
         [0009]    The air curtains surrounding the equipment provide the same benefit as a rack cooling system without the need for enclosures and additional equipment that has to be maintained. The system of the present invention provides at least the following benefits: 
         [0010]    (1) reduced electrical operating costs; 
         [0011]    (2) simpler construction; 
         [0012]    (3) overall cost saving of equipment; 
         [0013]    (4) a more “green” arrangement; 
         [0014]    (5) an annual operating cost savings due to less equipment, controls and maintenance; and 
         [0015]    (6) due to the lower amount of heat rejection required by the primary HVAC system and with the use of air curtains, this results in less tonnage of the HVAC system required to maintain room design criteria. 
         [0016]    To accomplish the foregoing and other advantages and features of the present invention there is provided a system for removing heat from heat load equipment comprising:
       an air-conditioning unit for circulating air down aisles about the equipment;   a re-circulating air handling unit for establishing an air curtain that flows up from and around the heat load equipment to a return for the air curtain;   and one or more roof-mounted heat stratification housings disposed over the heat load equipment for receiving heat from the equipment forced from the air curtain that is below;   the heat stratification housing including a plurality of heat transfer plates that extend between interior and exterior areas thereof.       
 
         [0021]    In accordance with other aspects of the present invention the plurality of heat transfer plates may be supported in a parallel array; each heat stratification housing may comprise a tower having opposite walls that each support an array of heat transfer plate; each plate may extend between the interior area of the housing and outside of the housing; an array of liquid nozzles is disposed outside of the heat stratification housing and directed at the heat transfer plate to provide evaporative cooling, and an exhaust fan for drawing air from the heat transfer plates; an evaporative cooling water manifold and a pump may be provided for directing water to the manifold and from the manifold to the nozzles; an external housing for the nozzles, a sump drain from the external housing and slotted air openings in the external housing for evaporative cooling may be provided; the re-circulating air handling unit directs air to floor diffusers that are disposed about the heat load equipment for establishing respective air curtains about the heat load equipment; a heat reclaim system may be provided within the heat stratification housing and a drain pan on the inside of the heat stratification housing under the heat transfer plates. 
         [0022]    In another version of the invention there is provided a building system for containing and dissipating heat from heat load equipment, said building system comprising: 
         [0023]    a building structure having a floor and a roof; 
         [0024]    at least one heat stratification housing mounted at the roof and including at least one side wall that partially forms an internal housing area; 
         [0025]    a plurality of heat transfer plates that each extend across the side wall of the stratification housing between the internal housing area and outside of the stratification housing; 
         [0026]    a re-circulating air handling unit for establishing an air curtain that flows up from and around the heat load equipment; 
         [0027]    said re-circulating air handling unit arranged at the floor of the building structure; 
         [0028]    the at least one heat stratification housing being disposed over the heat load equipment for receiving heat from the air curtain; 
         [0029]    and a cooling system including a fan adjacent the heat stratification housing for drawing heat from the heat transfer plates. 
         [0030]    In accordance with still other aspects of the present invention the plurality of heat transfer plates may be supported in a parallel array, each heat stratification housing comprises a tower having opposite walls that each support an array of heat transfer plates, and each plate extends between the interior area of the housing and outside of the housing; an array of liquid nozzles may be disposed outside of the heat stratification housing and directed at the heat transfer plates to provide evaporative cooling; an evaporative cooling water manifold and a pump for directing water to the manifold and from the manifold to the nozzles may be provided; an external housing for the nozzles, a sump drain from the external housing and slotted air openings in the external housing for evaporative cooling may be provided; the re-circulating air handling unit may direct air to floor diffusers that are disposed about the heat load equipment for establishing respective air curtains about the heat load equipment; a heat reclaim system may be provided within the housing and a drain pan on the inside of the heat stratification housing under the heat transfer plates. 
         [0031]    In still another version there is provided a method of removing heat from heat load equipment that is contained in a building structure having a floor and roof, said method comprising the steps of: 
         [0032]    providing at least one heat stratification housing that supports a plurality of heat transfer plates; 
         [0033]    mounting the at least one heat stratification housing at the roof of the building structure; 
         [0034]    re-circulating air about the heat load equipment for establishing an air curtain that flows up from and around the heat load equipment; 
         [0035]    the air from the air curtains causing the heat from the equipment to rise to the at least one heat stratification housing; 
         [0036]    and extracting the heat from the heat transfer plates by one of water cooling evaporation and dry cooling. 
         [0037]    For water cooling there may be provided for spraying water on the heat transfer plates and exhausting the air from the heat transfer plates. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0038]    It should be understood that the drawings are provided for the purpose of illustration only and are not intended to define the limits of the disclosure. The foregoing and other objects and advantages of the embodiments described herein will become apparent with reference to the following detailed description when taken in conjunction with the accompanying drawings in which: 
           [0039]      FIG. 1  is a schematic illustration of one of the stratification housings or towers of the present invention; 
           [0040]      FIG. 2  is a schematic elevation view of a system in accordance with the present invention illustrating the load equipment, heat stratification housings and re-circulating air handling system; 
           [0041]      FIG. 3  is a schematic elevation view showing further details of the evaporative cooling water manifolds used with the system of the present invention; 
           [0042]      FIG. 4  is a floor plan showing the HVAC system associated with the load equipment; 
           [0043]      FIG. 5  is a floor plan of the HVAC system and its components; 
           [0044]      FIG. 6  is a schematic elevation view showing the re-circulating air handling unit and its components; and 
           [0045]      FIG. 7  is a perspective view illustrating one of the stratification towers with the heat transfer plates. 
       
    
    
     DETAILED DESCRIPTION 
       [0046]    The present invention is embodied in a system that combines heat stratification with an HVAC system so as to optimize heat rejection while reducing the size of the HVAC system. The system of the present invention allows the design of the building or facility that contains the high-density heat load equipment to be part of the heat dissipation solution by basically incorporating two separate zones. These two separate zones are demarcated, for example, as illustrated in  FIG. 6  by the demarcation line L. This separates the clean room heat stratification zone  24  from the clean room conditioned zone  25 . The demarcation line L is approximately at the height of the high-density heat load equipment  27  as depicted in  FIG. 6 . The heat stratification zone is for the storage and rejection of heat through the one or more heat stratification housings H. The conditioned zone is basically the cubic footage of the space that houses the high-density heat load equipment  27 . The equipment  27  may be of any type such as used at large computer centers including server rooms and information technology rooms. 
         [0047]    Thus, in accordance with the present invention it is preferred that the building or facility not have traditional ceilings. This allows the heat stratification zone  24  to basically begin at a height equal to the recirculating air handling unit  23  with air returns  14  above the high-density heat load equipment  27 . The heat identified in the drawings by the arrow X travels, under the force of the air curtain, up into the stratification zone for rejection in the stratification housings H. The heat is coupled through the heat transfer plates  4  to the exterior of the housing and is disposed of through evaporative cooling in which the spray nozzles  6  spray the external portion of the heat transfer plates. Exhaust fans  11  draw air across the heat transfer plates and discharge the heat above the housing structure. By allowing the heat to stratisfy using the heat stratification housings and related HVAC system, the majority of the heat is allowed to stratisfy and be discharged through the heat stratification housings H. This allows for smaller HVAC equipment and less electrical consumption. 
         [0048]    The heat stratification housings H are depicted in  FIGS. 1 ,  2  and  7 .  FIG. 1  depicts a single housing H while  FIG. 2  schematically illustrates more of an overall facility.  FIG. 2  illustrates three such housings H.  FIG. 7  is a perspective view illustrating a single housing H and associated heat transfer plates or fins  4 . 
         [0049]      FIG. 1  shows the heat stratification housing H along with the oppositely disposed heat transfer plates  4 , the heat reclaim system at  26 , water spray nozzles  6 , evaporative cooling water manifolds  5 , water pumps  9  for evaporative cooling, and fans  11  that may be used for both evaporative cooling and dry cooling. This combination allows the heat rejection through the use of evaporative cooling. For environments where the housings are expected to be subjected to temperatures below 32° then dry cooling is preferred without the use of water. 
         [0050]      FIGS. 1 and 2  depict one embodiment of a stratification housing H. It is understood that various different configurations and shapes of housings may be employed. As shown in  FIG. 2 , three of these housings are used extending from the roof R.  FIG. 2  also shows the facility F without any ceiling between the high-density heat load equipment  27  and the housings H. Each of the housings or towers include an exterior wall surface  1 . The exterior surface may be constructed of metal or plastic suitable for an exterior environment and an evaporative condensing environment. The housing H also includes an interior stratification housing wall surface  2 . The surface  2  may be constructed of a material such as wallboard or other materials that may be employed in a clean room and that preferably equal or surpass the ISO design criteria for the room. Between the wall surfaces  1  and  2  there is provided an insulating material  3 . The insulating material may be foam, fiberglass or any type of insulating material capable of providing protection to prevent condensation. 
         [0051]    Each of the housings H support on either side thereof heat transfer plates or fins  4 . The heat transfer plates are preferably constructed of metal so as to allow the transfer of heat from the inside of the stratification housing to the exterior of the stratification housing. The plates  4  may be supported from the housing an any number of different ways, but in a fixed position relative to the housing H. The height, length and thickness, as well as the quantity of the transfer plates is determined by the amount of BTU&#39;s in the room to be rejected. Plate capacity may be added to comply with room redundancy requirements to meet standards for classification of application and ISO or other standards that govern design criteria. The heat stratification housing itself may be provided in sets thereof on a building that is, for example, 200 feet long and 200 feet wide. In such a size facility a total of four housings may be provided each measuring 180 feet in length, 40 feet wide and 30 feet high. The room or facility layout and equipment loads determines the size of each of the housings. 
         [0052]    On the interior of the stratification housing, the plates  4  are for the most part exposed with only an interior drain pan  10  disposed there-under as illustrated in  FIG. 1 . On the outside of the housing H, there is provided a support housing J as illustrated in  FIG. 1 . Associated with the housing J is an evaporative cooling water manifold  5 . The manifold  5  may be constructed of plastic. The manifold  5  supplies water to the water spray nozzles  6  that are schematically depicted in  FIG. 1 .  FIG. 1  shows an array of nozzles  6 . Each of the array of nozzles may direct water to one or more of the heat transfer plates  4 . Also, more than one array of nozzles may be provided along the length of all of the heat transfer plates  4 . The water spray nozzles  6  spray water provided by the evaporative cooling water manifold. The quantity of water directed from the spray nozzles and the GPM rating for each nozzle is to be determined by the amount of heat rejection that is desired. 
         [0053]    Referring now to  FIGS. 1-3 , and particularly to  FIG. 3 , it is noted that some of the external components associated with the stratification housing are shown in somewhat more detail. This includes the water nozzles  6  that are directed at the heat transfer plates  4  and the manifold  5  that feeds the nozzles  6 . A sump drain  7  at the bottom of housing J is also illustrated in  FIGS. 1 and 3 . This may be in the form of a ball valve connected to the bottom of the external wet housing J. This allows for the draining of water from the housing J. The housing J preferably also includes slotted air openings  8  in a wall thereof that may be of metal or plastic. This allows air to supply the evaporative cooling or free cooling across the heat transfer plates  4 . The manifolds  5  are supplied from the water pump  9  also illustrated in  FIG. 3 .  FIG. 3  also illustrates on the inside of the housing H the interior drain pan  10 . This is preferably constructed of an insulated material and may be either plastic or metal. The drain pan  10  collects condensation that may collect on the heat transfer plates  4 . The drain pan is insulated to avoid condensation occurring on the interior wall of the drain pain. Any collected condensation is discharged from the pan to the roof R. 
         [0054]    At the top of the housing J there is provided a fan  11 . The fan  11  is for evaporative cooling or dry cooling depending upon the outside climate temperatures. The fan section  11  may be considered as part of the external housing and is constructed so as to provide adequate discharge of air as in the direction of arrow B in  FIG. 1 . 
         [0055]      FIG. 3  also schematically illustrates a reflective screen  28  that may be used on the inner side of the heat transfer plates  4 . The reflective screen may be selectively operated and may be raised and lowered to provide protection against overcooling and to maximize the reclaiming of heat. The screen  28  may be controlled by temperature sensors that monitor the interior temperature of the housing as well as ambient temperature and the reclaimed water temperature. The screen  28  moves up or down to cover the amount of heat transfer plates necessary to allow efficient use of heat rejection and heat reclaiming. 
         [0056]    Reference is now made to  FIG. 2  which depicts more of the overall system in accordance with the present invention. This depicts the use of a plurality of stratification housings H associated with the facility F.  FIG. 2  also depicts a floor slab  30  along with a raised floor  32  that defines a recirculating chamber or plenum  34 . The underfloor supply air system  12  is schematically illustrated as connecting the recirculating air handling unit  23 , via the plenum  34  to the slot diffusers  13 . The underfloor supply air system may comprise duct work that may be constructed of metal or plastic and is insulated. The slot diffusers  13  are disposed on all four sides of the heat generating equipment  27  and form an air curtain illustrated in  FIG. 2  by the arrows  36 . The recirculation is completed back to the unit  23  by means of a return line indicated at  14  in  FIG. 2 . This may include return registers mounted at the height of the equipment  27 . The air temperature may be controlled to be at 55° (or is adjustable), CFM and velocity to be determined by the footprint of the equipment being cooled. The return air indicated at  15  in  FIG. 2  from the air curtain registers to the recirculating air handling unit  23  may be metal or plastic. The line  14  in  FIG. 2  corresponds to the line L illustrated in  FIG. 6 . 
         [0057]    The equipment  27  is normally provided with its own fan system so as to draw air from the direction  16  shown in  FIG. 6 , through the equipment (thus passing the heat out of the equipment) to the direction  17  shown in  FIG. 6 , where the heat is captured by the air curtain  36  and directs the heat, represented in  FIG. 6  by arrow X, to the stratification housings H. The air curtains function as propelling means to direct the heat from the equipment up into the stratification zone  24 . 
         [0058]    With respect to the slot diffusers  13 , reference is also made to the plan view of  FIG. 4  as well as the schematic diagram of  FIG. 6 .  FIG. 6  also shows the air handling unit  23  and the heat generating equipment  27 . The slot diffusers  13  are illustrated in  FIG. 6 , and furthermore, the plan view of  FIG. 4  shows the diffusers  13  as disposed about the equipment  27  on all four sides thereof so as to provide air curtains directed upwardly about all sides of the equipment  27  toward the return at  14 . The diffusers are basically at the level of floor  32 .  FIG. 6  also shows, at  16 , the cooling air flow directed to the equipment  27  coming from the 55° F. (or is adjustable) environment of the air curtain that is directed upwardly about each of the pieces of equipment  27 .  FIG. 6  also illustrates schematically at  17  the heat being generated from the equipment inside the air curtain, rising inside the air curtain up to the stratification housings H. This heat is identified in  FIG. 6  by arrow X. This heat is also illustrated schematically in  FIGS. 1 and 2  by the arrow X. The slot diffusers  13  are basically in the form of slotted ports on each side of the heat generating equipment  27  at floor level. The air handling unit  23  directs air flow through these slot diffusers to form the air curtains  36  as schematically illustrated in  FIG. 2 .  FIG. 6  schematically illustrates the manner in which the flow from the heat or air curtains directs dissipated heat as indicated by the directional arrow X in  FIG. 6 . 
         [0059]      FIG. 4  is a plan view showing the primary HVAC system and the configuration of the various components that comprise this system. It is noted that  FIG. 4  also depicts the heat generating equipment  27  and the position of the slot diffusers  13  that are associated with the recirculating air handling system with slots on each side of the equipment. In  FIG. 4  the primary HVAC system blows down the aisles from wall mounted grills. The height of the grills is not to exceed air curtain return heights. The return air is drawn through the floor for return to the primary HVAC unit. In this regard,  FIG. 5  is an illustration of an elevation of the primary HVAC system supply which may be wall mounted and the return which may be connected to the underside of the raised floor by the use of the under floor space as a return air plenum. Note in  FIG. 5  the return air plenum at P. 
         [0060]      FIG. 5  illustrates the primary HVAC system  18  for the room. This system may use cubic footage of the room to the height of the equipment and deduct the cubic footage of the air curtains in determining its capacity. The system  18  is considered as a horizontal system for air conditioning.  FIG. 4  also depicts the primary HVAC unit at  22  for supplying air to the ducted supply system. This unit may include chilled water or other cooling, hot water, steam or an electric heating cool. The preheat and reheat coils maintain room design temperature. Humidification may also be provided to maintain the relative humidity required in the space. Refer also to  FIGS. 4 and 5  for the HVAC system supply air duct  19 . This duct may be made of metal or plastic and delivers the 72° F. (or is adjustable) air down the aisles as illustrated by arrows C in  FIG. 4 . This serves the cubic footage of the room that is not served by the air curtain system into a height not to exceed the top of the equipment in the associated with the air curtains.  FIG. 5  also illustrates the primary HVAC unit return at  20 . This may be through a perforated raised floor for connection to return air ducts or under the floor space may be used as a return air plenum. In this connection refer also in  FIGS. 4 and 5  to the raised floor perforated returns at  21 . They allow the air to move from the top of the raised floor to the underside of the raised floor to the plenum P. 
         [0061]    The recirculating air handling unit  23  is schematically depicted in  FIGS. 2 and 6 . This unit provides CFM and static pressure for the air curtain. The unit  23  may use chilled water or a DX coil and hot water, steam or electric heating. There may be preheat and reheat coils sized to maintain air curtain temperature. There may also be provided associated with unit  23  a humidifier to maintain the desired relative humidity. 
         [0062]    As mentioned previously,  FIG. 6  shows an elevation view of the recirculating air handling unit  23  with its supply duct  12  connected to the slot diffusers  13  on all sides of the equipment  27 . The return air at the top of the equipment also on all four sides is approximately in line with the demarcation between the zones  24  and  25 . Again, the zone  24  is considered as a stratification zone in a space above the equipment  27  and including the heat stratification housings. The conditioned air zone  25  is the area from the floor to the top of the equipment  27 .  FIG. 6  also shows the heat being released from the equipment at  17  rising inside the air curtain to the stratification zone above the equipment for rejection in the heat stratification housings H. The aforementioned air curtain is represented by air columns that extend upwardly such as in the direction of arrows  36  in  FIG. 2  to direct the heated air in the direction of arrow X toward the heat stratification housings H. 
         [0063]      FIG. 1  also schematically illustrates a heat reclaim system at  26 . This may be comprised of circulating water for use in a building heating system or for domestic hot water. For this purpose the system may include copper or steel piping with fins to maximize the transfer of heat to the recirculating water. 
         [0064]    Having now described a limited number of embodiments of the present invention, it should now be apparent to one skilled in the art that numerous other embodiments and modifications thereof are contemplated as falling within the scope of the present invention as defined by the appended claims.