Abstract:
An air handling system for selectively and incrementally heating a flow of inlet air entering the air handling system through an inlet opening includes a first heating coil assembly in fluid communication with a first inlet manifold header and a first outlet manifold header, and a second heating coil assembly in fluid communication with a second inlet manifold header and a second outlet manifold header. The first heating coil assembly is oriented forward of the second heating coil assembly such that the first heating coil assembly is disposed closer to the inlet opening than the second heating coil assembly.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit of U.S. Provisional Application Ser. No. 60/548,120, filed on Feb. 26, 2004, and herein incorporated by reference in its entirety. 
     
    
     FIELD OF THE INVENTION  
       [0002]     This invention relates in general to a multi-zone integral face bypass coil system, and deals more particularly with a multi-zone integral face bypass coil system that provides greater flexibility with two or more heating zones, and greater protection against damaging environmental condition, than known systems.  
       BACKGROUND OF THE INVENTION  
       [0003]     Integral face bypass (IFB) coil systems are known in the art and typically employ a single input and output header for feeding a predetermined amount of hot water or steam through a series of heating coils. The coils are themselves disposed within selectively actuating damper devices, which open and close by a given degree in order to permit a varying amount of inlet air to pass directly over the coils.  
         [0004]     While these known integral face bypass coil systems are successful to a degree, it is desirable to increase the efficiency of such systems. That is, known integral face bypass coil systems, commonly referred to as VAV (Variable Air Volume) systems, are increasingly being asked to provide for heating requirements over a wide span of temperature ranges and circulation volumes. If the swing in the desired volume of air being processed by known integral face bypass coil systems is too great, it is possible that the pressure within the coils can drop to levels that may lead to the freezing of condensate in the coils, and thus related structural damage or failure.  
         [0005]     Similarly, known integral face bypass coil systems must be manufactured to handle wide swings in the volume of treated air, therefore the components in these systems are large in size, and may in fact be ‘over-built’ when the systems are utilized in small-volume applications. Moreover, the damper-drive assemblies of known integral face bypass coil systems are complex and that take up a fair amount of room, as well as being less precise than possible due to the large number of linkages utilized in such assemblies.  
         [0006]     Still yet another aspect of known integral face bypass coil systems that may be improved lies in the nature, complexity and expense of the valves utilized therein. That is, owing to the use of variable speed blowers and variable air volume control systems, many known integral face bypass coil systems utilize modulating valves that maintain desired pressure, but often fall short of desired steam volume.  
         [0007]     With the forgoing problems and concerns in mind, it is the general object of the present invention to provide a multi-zone integral face bypass coil systems which overcomes the above-described drawbacks while maximizing effectiveness, flexibility and environmental hardiness.  
       SUMMARY OF THE INVENTION  
       [0008]     It is an object of the present invention to provide a multi-zone, vertical integral face bypass (VIFB) apparatus.  
         [0009]     It is another object of the present invention to provide a multi-zone, VIFB apparatus having two or more heating manifolds.  
         [0010]     It is another object of the present invention to provide a multi-zone, VIFB apparatus that provides protection against damaging environmental conditions.  
         [0011]     It is another object of the present invention to provide a multi-zone, VIFB apparatus that may be fashioned from smaller gauge materials, and smaller diameter piping.  
         [0012]     It is another object of the present invention to provide a multi-zone, VIFB apparatus that is more energy efficient.  
         [0013]     It is another object of the present invention to provide a multi-zone, VIFB apparatus that provides more precise temperature conditioning than known single-manifold systems.  
         [0014]     It is another object of the present invention to provide a multi-zone, VIFB apparatus that utilizes direct-driven dampers.  
         [0015]     In accordance, therefore, with one embodiment of the present invention, an air handling system for selectively and incrementally heating a flow of inlet air entering the air handling system through an inlet opening includes a first heating coil assembly in fluid communication with a first inlet manifold header and a first outlet manifold header, and a second heating coil assembly in fluid communication with a second inlet manifold header and a second outlet manifold header. The first heating coil assembly is oriented forward of the second heating coil assembly such that the first heating coil assembly is disposed closer to the inlet opening than the second heating coil assembly.  
         [0016]     These and other objectives of the present invention, and their preferred embodiments, shall become clear by consideration of the specification, claims and drawings taken as a whole. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]      FIG. 1  illustrates a known vertical integral face bypass (VIFB) apparatus.  
         [0018]      FIG. 2  illustrates a simplified, schematic plan-view representation of the heating coils and clam-shell dampers arranged in the VIFB apparatus of  FIG. 1 , when the clam-shell dampers are in their fully open position.  
         [0019]      FIG. 3  illustrates a simplified, schematic plan-view representation of the heating coils and clam-shell dampers arranged in the VIFB apparatus of  FIG. 1 , when the clam-shell dampers are in their partially closed position.  
         [0020]      FIG. 4  illustrates a simplified, schematic plan-view representation of the heating coils and clam-shell dampers arranged in the VIFB apparatus of  FIG. 1 , when the clam-shell dampers are in their fully closed position.  
         [0021]      FIG. 5  illustrates a VIFB apparatus in accordance with one embodiment of the present invention.  
         [0022]      FIG. 6  illustrates a partial cross-sectional view A-A of the VIFB apparatus shown in  FIG. 5 .  
         [0023]      FIG. 6A  illustrates a partial cross-sectional view a VIFB apparatus in accordance with another embodiment of the present invention.  
         [0024]      FIG. 7  illustrates a simplified, schematic plan-view representation of the heating coils and clam-shell dampers arranged in the VIFB apparatus of  Figure 5 .  
         [0025]      FIG. 8  illustrates a direct-drive damper system utilized with the VIFB apparatus of  FIG. 5 .  
         [0026]      FIG. 9  is a magnified view of the direct-drive damper system shown in  FIG. 8 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0027]      FIG. 1  illustrates a prior art IFB apparatus  100 . In particular,  FIG. 1  illustrates a known vertical integral face bypass (VIFB) apparatus  100  having a single inlet manifold header  102  and a single outlet manifold header  104  for supplying heated water, steam or the like to a series of interconnected, vertically oriented heating coils  106 . A series of clam-shell dampers  108  are utilized to selectively isolate the heating coils  106 , to a greater or lesser extent, from the flow of outside, or inlet, air. A complex set of interconnected linkages  110  are mounted to the VIFB apparatus  100  to control the selective positioning of the clam-shell dampers  108 .  
         [0028]      FIGS. 2-4  show a simplified, schematic plan-view representation of the heating coils  106  as arranged in the VIFB apparatus  100 . As shown in  FIG. 2 , the clam-shell dampers  108  are fully opened, thus causing a maximum of inlet air flow over and about the heating coils  106 . When oriented in the manner shown in  FIG. 2 , the clam-shell dampers  108  enable the greatest possible heat transfer between the inlet air and the heating coils, and thus provide the greatest temperature increase to the inlet air.  
         [0029]     In those circumstances where the inlet air need not be warmed to the extent necessary as in  FIG. 2 , the clam-shell dampers  108  may be selectively controlled so as to close part-way, as shown in  FIG. 3 , thus restricting to a certain degree the amount of inlet air flow over and about the heating coils  106 . When oriented in the manner shown in  FIG. 3 , the clam-shell dampers  108  enable a graduated heat transfer characteristic between the inlet air and the heating coils, thus providing a variable temperature increase to the inlet air.  
         [0030]      FIG. 4  now illustrates that condition of the VIFB  100  in which it is desirable to isolate the inlet air from the heating coils  106  to the greatest extent possible, thus minimizing the heat transfer between the heating coils  106  and the inlet air flow. As depicted in  FIG. 4 , the clam-shell dampers  108  are in their fully closed position, thus permitting the inlet air to bypass direct contact with the heating coils  106  during those times when it is determined that the inlet temperature does not need to be significantly raised.  
         [0031]     While the known VIFB apparatus  100  has been shown and described in connection with  FIGS. 1-4 , the efficiency and reliability of these known systems suffer somewhat when asked to deliver temperature conditioning to an inlet air flow over a wide temperature and/or volumetric range.  
         [0032]     That is, as discussed previously, known VIFB apparatuses are typically fashioned to have relatively large inlet and outlet manifold headers,  102  and  104  respectively, and heating coils  106 , so as to accommodate large temperature rises in the inlet air, or large increases in the volume of inlet air to be conditioned. Such systems, however, typically suffer when the increase in air flow temperature is desired to be much smaller; that is, when the ΔT (the instructed rise in the temperature of the outside inlet air) is small, or when the volume or air to be conditioned is small.  
         [0033]     For example, in those cases where the ΔT is small, it may not be sufficient for the clam-shell dampers  108  to close fully, as shown in  FIG. 4 . That is, even with the clam-shell dampers  108  fully closed, the temperature rise of the inlet air may still exceed the desired temperature rise. Thus, in prior art VIFB apparatuses, it is known to reduce the flow of hot water or steam being directed through the heating coils  106 , to thereby further reduce the rise in temperature of the inlet air.  
         [0034]     As will be appreciated, when the flow rate within the heating coils  106  is reduced, the pressure within the heating coils  106  is correspondingly reduced and the VIFB apparatus  100  therefore becomes susceptible to environmentally-induced damage, such as freezing. Moreover, it is also practically difficult to precisely regulate the incremental reduction of flow-rate and pressure within the heating coils  106  so as to provide the type of fine temperature control oftentimes needed in modern day buildings.  
         [0035]     Complicating the fine control of known VIFB apparatuses even further is the complex set of linkages  110  that control the selective positioning of the clam-shell dampers  108 . Not only are known damper linkages  110  relatively cumbersome and space-consuming, their numerous integral components each contribute a measured amount of mechanical tolerances, or ‘play’, thus making the overall control of the clam-shell dampers  108  less definable and accurate.  
         [0036]     Thus, known VIFB apparatuses as shown in  FIGS. 1-4  are vulnerable in those applications where large temperature and/or volumetric swings may be experienced, and where the fine and incremental control of temperature rise is desired.  
         [0037]     The present invention addresses the problems of known VIFB apparatuses, and provides an architecture that not only accommodates the conditioning of inlet air flow over wide temperature and volumetric ranges, but does so without endangering the integral heating coils, via freezing or the like. Moreover, the present invention removes the complex linkages of known VIFB apparatuses with a direct-connection control for the clam-shell dampers, as discussed hereinafter.  
         [0038]      FIG. 5  illustrates a VIFB apparatus  200 , in accordance with one embodiment of the present invention. As shown in  FIG. 5 , the VIFB apparatus  200  includes a first inlet manifold header  202  which communicates with a first outlet manifold header  210 . Together with an integral first set of heating coils  206 , the first inlet and outlet manifold headers,  202  and  210  respectively, act as a first, stand-alone heating/conditioning assembly  209 .  
         [0039]     As is also shown in  FIG. 5 , and in stark contrast to known VIFB devices, the VIFB apparatus  200  further includes a second inlet manifold header  208  which communicates with a second outlet manifold header  204 . Together with an integral second set of heating coils  212 , the second inlet and outlet manifold headers,  208  and  204  respectively, act as a second, stand-alone heating/conditioning assembly  213 . Both the first set of heating coils  206  and the second set of heating coils  212  are disposed within a common clam-shell damper  214 . As will be appreciated, and similar to known devices, the VIFB apparatus  200  includes a plurality of selectively actuating clam-shell dampers  214  to control the amount of inlet air incident upon the first and second sets of heating coils,  206  and  212 , although only one such damper assembly is shown in  FIG. 5  for clarity&#39;s sake.  
         [0040]      FIG. 6  illustrates a partial cross-sectional view A-A of the VIFB apparatus  200  shown in  FIG. 5 . As shown in  FIG. 6 , the second heating/conditioning assembly  213  is disposed in a sheltered relationship behind the first heating/conditioning assembly  209 . Therefore, in accordance with a preferred embodiment of the present invention, the first heating/conditioning assembly  209  is oriented forward of the second heating/conditioning assembly  213  within each of the clam-shell dampers  214 , as shown in  FIG. 7 . That is, the present invention locates the first heating/conditioning assembly  209  in front of the second heating/ conditioning assembly  213  and closer to the air inlet side of the VIFB apparatus  200 . Thus, during those times when the clam-shell dampers  214  are in their at least partially-opened position, the inlet air flow {overscore (F)} is firstly and primarily incident upon the first heating/conditioning assembly  209 .  
         [0041]     It is therefore an important aspect of the present invention that the first heating/conditioning assembly  209  not only accomplishes the conditioning of inlet air, but also acts as an environmental barrier to the second heating/conditioning assembly  213 . Thus, as will be described in more detail below, the first heating/conditioning assembly  209  acts to prevent freezing of the second heating/conditioning assembly  213 .  
         [0042]     In a preferred method of operation, and specifically in those applications where the VIFB apparatus  200  must operate over a wide temperature and/or volumetric range, the first heating/conditioning assembly  209  is operated at a substantial, to substantially maximum, capacity, thus insuring that the first heating/conditioning assembly  209  enjoys a high pressure, high flow-rate environment of heated water, steam or the like at all times. The selective operation of the clam-shell dampers  214  will thereby permit the first heating/conditioning assembly  209  to effectuate accurate, precise and efficient control over, approximately and at least, the first half of the total temperature range of the VIFB apparatus  200 .  
         [0043]     The second heating/conditioning assembly  213  need only then be operated in those high ΔT conditions when the temperature differential between the inlet air and the instructed air flow temperature is approximately outside of the first half of the total temperature range of the VIFB apparatus  200 , and therefore outside of the ability of the first heating/conditioning assembly  209  to adequately address.  
         [0044]     In such high ΔT situations, the second heating/conditioning assembly  213  can be selectively actuated by the operation of valves and the like, the workings of which are commonly known to those in the art. When so actuated, the second heating/conditioning assembly  213  supplements the ability of the clam-shell dampers  214  and the first heating/conditioning assembly  209 , to accomplish a system-instructed rise in the temperature of the inlet air anywhere within the total temperature range of the VIFB apparatus  200 .  
         [0045]     The present invention thus provides a multi-zone approach to the conditioning of inlet air, in which two separate heating/conditioning systems are selectively utilized to accomplish system-instructed temperatures rises in inlet air over a wider range of temperatures, and with a level of precision and efficiency not heretofore known in the art.  
         [0046]     In contrast to known systems, the multi-zone VIFB apparatus  200  of the present invention provides a second, and separate, manifold header assembly  208 / 204  that feeds a separate, matching second set of heating coils  212 . By providing the second set of heating coils  212 , and by selectively activating them on a case by case basis in dependence upon the volume of conditioned air required by the control system, or in times of high ΔT requirements, the present invention can ease the burden currently placed upon the single header/heating coil arrangement of known systems.  
         [0047]     In low ΔT conditions when the temperature differential between the inlet air and the instructed air flow temperature is approximately within the first half of the total desired temperature range of the VIFB apparatus  200 , the second heating/conditioning assembly  213  is operated at a minimum, to substantially negligible, capacity. That is, the second heating/conditioning assembly  213  can be largely inactive in those situations where the first heating/conditioning assembly  209  (by acting in combination with the clam-shell dampers  214 ) is capable of fully accomplishing a system-instructed rise in the temperature of the inlet air.  
         [0048]     It should of course be understood that although operation of the VIFB apparatus  200  has been chiefly discussed in connection with accomplishing the instructed rise in the temperature of the inlet air stream, the applicability of the present invention is not so limited. Indeed, the selective actuation of the second heating/conditioning assembly  213  may be alternatively controlled by the volumetric demands placed upon the VIFB apparatus  200 . In this regard, when the volume of inlet air to be conditioned is within the capacity of the first heating/conditioning assembly  209 , taking into account the instructed temperature rise in that volume of inlet air, the second heating/conditioning assembly  213  remains inactive. However, should the volume, or combination of volume and instructed temperature rise, in the inlet air stream be beyond the design specifications of the first heating/ conditioning assembly  209 , the control system of the VIFB apparatus  200  may selectively actuate the second heating/conditioning assembly  213  to compensate for the same.  
         [0049]     It is therefore yet another important aspect of the present invention that the second heating/conditioning assembly  213  may be only selectively utilized, thus making the overall VIFB apparatus  200  more efficient over its entire temperature and volumetric range by only coming ‘on-line’ when needed.  
         [0050]     Another important aspect of the present invention lies in the increased efficiency in the VIFB apparatus  200 , as compared to known single-manifold header systems. By utilizing two separate, yet complimentary, stand-alone heating/conditioning assemblies, the present invention is capable of finer and more precise control over the entire temperature and volumetric range of the VIFB apparatus  200 .  
         [0051]     The present invention also envisions disposing the second set of heating coils  212  behind the first set, thereby insulating the second set from environmental damage. That is, by orienting the second set of heating coils  212  in a sheltered position behind the first set of heating coils  206 , and by continually pressurizing the first set of coils at or near their maximum, the heated water or steam coursing through the first set of heating coils  206  provides a friendly environmental zone within which the second set of heating coils  212  are enveloped and therefore protected from freezing temperatures, even when the second set of heating coils  212  is run at low pressures, or completely shut off.  
         [0052]     Indeed, a preferred embodiment of the present invention can be seen in  FIG. 6A  in which the second heating/conditioning assembly  213  is completely sheltered behind the first heating/conditioning assembly  209 , including the second outlet manifold header  204 . It will be readily appreciated that the second outlet manifold header  204  may be oriented completely behind the first heating/conditioning assembly  213 , as shown in  FIG. 6A , or in the alternative position shown in  FIG. 5 , without departing from the broader aspects of the present invention.  
         [0053]     It is another important aspect of the present invention that as the first set of heating coils  206  are continually operated at a high, if not maximum, capacity, the first set of heating coils  206  are themselves protected against freezing.  
         [0054]     Still yet another important aspect of the present invention is that the proposed multi-zone integral face bypass coil system is capable of utilizing simple slow-acting steam valves, instead of the complex seat valves typically utilized with known single-coil designs.  
         [0055]     Moreover, by providing two separate manifold headers/heating coil assemblies, the size and gauge of the constituent components of the headers and the coils may be correspondingly reduced for each assembly. That is, smaller diameter coils and smaller manifold header boxes may be employed, thus reducing material cost, labor and assembly time. Another advantageous effect of reducing the size of the components is that the overall weight and dimensions of the system as a whole can be substantially reduced.  
         [0056]     The present invention also replaces the complex linkages utilized in known systems to drive the clam-shell dampers, with a direct-drive damper system  300 . As shown in  FIG. 8 , the controlling arms  302  of the direct-drive damper system  300  are directly coupled to the control rods  304  attached to all of the clam-shell dampers  214 . Thus, the direct-drive damper system avoids the tolerances and calibration ‘play’ inherent in those systems, which utilize complex linkages.  
         [0057]     In contrast to the known complex and indirect damper linkage  110  shown in  FIG. 1 , the direct-drive damper system  300  of the present invention, shown in  FIGS. 8 and 9 , is face mounted to the VIFB apparatus  200 .  
         [0058]     It is therefore another important aspect of the present invention that the proposed direct-drive damper system is considerably smaller and may be arranged within the outer dimensions of the VIFB apparatus  200  (instead of being mounted so as to extend outwards from the VIFB apparatus, as shown in  FIG. 1 ), thus reducing the size requirements of the overall system.  
         [0059]     Moreover, as the controlling arms  302  of the direct-drive damper system  300  are rigidly fixed to both a drive hub  306  and to the control rods  304 , precise movement of the control rods  204  may be effectively accomplished without any of the mechanical ‘play’ inherent in the known, in-directly driven damper drives.  
         [0060]     Although the present invention has been described such that the first heating/conditioning assembly  209  is designed to address approximately half of the total temperature or volumetric range of the VIFB device, with the second heating/conditioning assembly  213  being selectively called upon to address the remaining approximate half of the total temperature or volumetric range, the present invention is not limited in this regard. Indeed, the VIFB apparatus  200  of the present invention may be selectively designed so that the first and second stand-alone heating/conditioning assemblies address a greater or lesser portion of the total system range in temperature or volume, in dependence upon the specific design characteristics needed for a given application.  
         [0061]     While the invention has been described with reference to the preferred embodiments, it will be understood by those skilled in the art that various obvious changes may be made, and equivalents may be substituted for elements thereof, without departing from the essential scope of the present invention. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed, but that the invention includes all equivalent embodiments.