Abstract:
An energy recovery ventilator wherein two of the air flow openings are in direct communication with either the fresh air space or the stale air space. The energy recovery ventilator has a housing with at least a first face panel holding a heat exchange device. The housing includes two air flow openings in the first face panel of the housing, in direct communication with the stale air space, and two other air flow openings in the housing in communication with the fresh air space through duct pipes. Alternatively, the first two air flow openings are in direct communication with the fresh air space, and the other two air flow openings are in communication with the stale air space through duct pipes. The energy recovery ventilator also includes a hinged bar mounting system and a control system. The features of the present invention facilitate ease of installation.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The present invention relates generally to air-to-air heat exchangers, otherwise known as energy recovery ventilators, and more particularly to an energy recovery ventilator with features facilitating ease of installation. The design of the present invention provides a more efficient and more cost effective method for installing an energy recovery ventilator.  
         [0002]     An energy recovery ventilator is generally used to exhaust stale air from a stale air space to a fresh air space and bring in fresh air from the fresh air space to the stale air space while exchanging heat or cool energy, thereby reducing heating or cooling requirements associated with fresh air introduction. Energy recovery ventilators are often used in connection with a heating or cooling system, wherein the stale air space is sometimes a return air duct of the heating or cooling system, and the fresh air space is generally the outdoors.  
         [0003]     When in use with a heating or cooling system, an outside air stream from the outdoors and a stale room air stream from the return air duct separately enter the energy recovery ventilator and pass through a heat exchange device. In passing through the heat exchange device, energy from the stale room air stream is transferred either to or from the outside air stream. The outside air stream then exits the energy recovery ventilator to the return air duct as a fresh air stream. The stale room air stream then exits the energy recovery ventilator to the outdoors as an exhaust room air stream.  
         [0004]     An energy recovery ventilator used in connection with a heating or cooling system typically comprises a housing holding a heat exchange device. The heat exchange device includes a heat exchanger. There are several types of heat exchangers that can be used in the heat exchange device, including rotating wheel, pipe, and plate types. In the prior art, the energy recovery ventilator is generally mounted on a wall or ceiling. The outside air stream and the stale room air stream generally enter the housing through duct pipes connected to two air flow openings in the housing. The fresh air stream and the exhaust room air stream exit the housing through two other duct pipes connected to two other air flow openings in the housing. The air flow openings are generally fitted with duct collar connections for connection to the duct pipes carrying each air stream to or from the fresh air or stale air spaces.  
         [0005]     An example of a prior art energy recovery ventilator used in connection with a heating or cooling system is shown in  FIG. 1 , illustrating the use of four air flow openings fitted with duct collar connections.  FIG. 1  shows a rectangular housing  10  and a heat exchange device  20 . The housing includes a first air flow opening  30  and a second air flow opening  32  in a first side panel  37  of the housing  10 , and a third air flow opening  34  and a fourth air flow opening  36  in a second side panel  39  of the housing, the first side panel  37  opposing the second side panel  39 . Each of the air flow openings  30 ,  32 ,  34 ,  36  is fitted with a duct collar connection  28  for connection to duct pipes. The heat exchange device  20  includes a diamond-shaped plate-type heat exchanger  22  such as the heat exchanger in U.S. Pat. No. 5,660,228, and a first fan  24  and a second fan  26  to induce air flow through the heat exchange device  20  and housing  10 .  
         [0006]     An outside air stream  50  from a fresh air space (not shown) enters the housing  10  from a first intake duct pipe (not shown) connected to the first air flow opening  30 . A stale room air stream  52  from a stale air space (not shown) enters the housing  10  from a second intake duct pipe (not shown) connected to the second air flow opening  32 . The outside air stream  50  and the stale room air stream  52  enter the heat exchanger  22 . The outside air stream  50  exits the heat exchanger  22  as a fresh air stream  56  that is driven by the first fan  24  to exit the housing  10  through the third air flow opening  34  connected to a first exhaust duct pipe (not shown) for delivery to the stale air space (not shown). The stale room air stream  52  exits the heat exchanger  22  as an exhaust room air stream  54  that is then driven by the second fan  26  and exits the housing through the fourth air flow opening  36  connected to a second exhaust duct pipe (not shown) for delivery to the fresh air space (not shown).  
         [0007]     The prior art energy recovery ventilator units are costly and cumbersome to install in that they require the installation of four separate duct pipes to carry each air stream to or from the fresh air or stale air spaces. Further, it is difficult for a single person to efficiently and easily install a prior art energy recovery ventilator, and contractors often go to the expense of sending two installers to the job to ensure that the installation is completed within specific time parameters.  
         [0008]     This invention relates to improvements over the ventilators described above, and to solutions to the problems raised or not solved thereby.  
       SUMMARY OF THE INVENTION  
       [0009]     The present invention provides an energy recovery ventilator wherein two of the air flow openings are capable of being in direct communication with either the fresh air space or the stale air space of a return air duct of a heating or cooling system. The energy recovery ventilator comprises a housing having at least a first face panel and holding a heat exchange device. The housing includes a first air flow opening and a second air flow opening in the first face panel of the housing, a third air flow opening in the housing, and a fourth air flow opening in the housing.  
         [0010]     In a preferred embodiment, the first air flow opening is in direct communication with the return air duct to receive stale room air from the return air duct, and the second air flow opening is in direct communication with the return air duct to deliver fresh air to the return air duct. The third air flow opening is in communication with the fresh air space to receive outside air from the fresh air space through an intake duct pipe, and the fourth air flow opening is in communication with the fresh air space to deliver exhaust room air to the fresh air space through an exhaust duct pipe.  
         [0011]     The energy recovery ventilator of the preferred embodiment can be installed in a number of different orientations and locations on the return air duct of a heating or cooling system. For example, the housing can be installed on the bottom of a horizontal section of the return air duct in a parallel or perpendicular orientation, on the side of a horizontal section of a return air duct in a parallel orientation, or on a vertical section of a return air duct in a parallel orientation.  
         [0012]     In another preferred embodiment, the first air flow opening and the second air flow opening are in direct communication with a fresh air space, such as the outdoors. The first air flow opening is in direct communication with the fresh air space to receive outside air from the fresh air space, and the second air flow opening is in direct communication with the fresh air space to deliver exhaust room air to the fresh air space. The third air flow opening is in communication with the stale air space to receive stale room air from the stale air space through an intake duct pipe, and the fourth air flow opening is in communication with the stale air space to deliver fresh air to the stale air space through an exhaust duct pipe. The energy recovery ventilator of this preferred embodiment can be installed on a wall using a through-the-wall accessory kit.  
         [0013]     The energy recovery ventilator of the present invention also includes a hinged bar mounting system to make installation easier and more efficient. The hinged bar mounting system comprises two hinge brackets, a first hinge bracket removably fastened to a mounting surface, such as a return air duct or a wall, and a second hinge bracket removably fastened to the housing. The first hinge bracket is shaped to engageably receive the second hinge bracket. The two hinge brackets thus engaged support the energy recovery ventilator with respect to the mounting surface, thereby enabling an installer to more easily connect the energy recovery ventilator to the return air duct or wall.  
         [0014]     The energy recovery ventilator of the present invention further includes a control system. The control system is built into the energy recovery ventilator and includes a plug-in power source. The control system will operate the energy recovery ventilator a portion of each hour based on the desired ventilation rate and the air flow capacity of the unit. In addition, the control system can be wired to the heating or cooling system to operate the heating or cooling system blower concurrently with the energy recovery ventilator.  
         [0015]     The present invention also contemplates a ventilation system comprising a heating or cooling system having a heating or cooling mechanism, a blower to induce air movement, a duct system including a return air duct, and an energy recovery ventilator installed on the return air duct. The energy recovery ventilator comprises a housing having at least a first face panel, a heat exchange device supported in the housing, a first air flow opening in the first face panel of the housing, a second air flow opening in the first face panel of the housing, a third air flow opening in the housing, and a fourth air flow opening in the housing. The first air flow opening and the second air flow opening are in direct communication with the return air duct. The ventilation system also includes a control system that operates the heating or cooling system blower concurrently with the energy recovery ventilator.  
         [0016]     The present invention further contemplates a method of installing the energy recovery ventilator. The method comprises the steps of pivotably connecting a hinge bracket on the energy recovery ventilator to a corresponding hinge bracket on the return air duct, rotating the energy recovery ventilator into a mounting position, and removably fastening the energy recovery ventilator to the return air duct. The method further comprises attaching a first and second duct pipe to the energy recovery ventilator, directly connecting a first air flow opening in the energy recovery ventilator to a first opening in the return air duct, and directly connecting a second air flow opening in the energy recovery ventilator to a second opening in the return air duct.  
         [0017]     There are a number of advantages of the present invention. First, the housing can mount directly to the return air duct of a heating or cooling system. Also, the housing requires only two separate duct pipes to be installed instead of four, saving installation time and cost. Installation of the energy recovery ventilator of the present invention is also very flexible because it can be installed in a number of different orientations and locations on the return air duct of a heating or cooling system, or on a wall, ceiling, or other mounting location as a stand-alone unit.  
         [0018]     In addition, the hinged bar mounting system allows one person to easily install the energy recovery ventilator, again saving time and cost associated with installation. Further, a built-in control system with a plug-in power source eliminates the need to further wire the control system to an existing electrical system in the building, unless concurrent operation with the heating or cooling system fan is desired. The control system can also facilitate good fresh air distribution in the building by minimizing fresh air stagnation in the return air duct through operation of the heating or cooling system fan concurrently with the energy recovery ventilator.  
         [0019]     Various other features, objects, and advantages of the invention will be made apparent to those skilled in the art from the accompanying drawings and detailed description thereof. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]      FIG. 1  is rear elevational view of one embodiment of a prior art energy recovery ventilator;  
         [0021]      FIG. 2  is an isometric view of a first embodiment of the energy recovery ventilator of the present invention installed directly on to a return air duct of a heating or cooling system, showing the energy recovery ventilator in phantom before being swung into position for installation;  
         [0022]      FIG. 3  an isometric view of a second embodiment of the energy recovery ventilator of the present invention installed directly on to a return air duct of a heating or cooling system, showing the energy recovery ventilator in phantom before being swung into position for installation;  
         [0023]      FIG. 4  is a side elevational view of the embodiment of  FIG. 2  and a top plan view of the embodiment of  FIG. 3  illustrating the use of a hinged bar mounting system;  
         [0024]      FIG. 4A  is an enlarged fragmentary exploded view of a portion of  FIG. 4  illustrating the use of a hinged bar mounting system;  
         [0025]      FIG. 5  is a side elevational view of the embodiment of  FIG. 2  and a top plan view of the embodiment of  FIG. 3  illustrating the use of a hinged bar mounting system;  
         [0026]      FIG. 6  is a rear isometric view of the embodiments of  FIGS. 2 and 3 ;  
         [0027]      FIG. 7  is an enlarged fragmentary isometric view of the portion of  FIG. 6  indicated by curve  7 - 7  illustrating the use of a hinged bar mounting system;  
         [0028]      FIG. 7A  is an enlarged fragmentary isometric view of the portion of  FIG. 6  indicated by line  7 - 7  similar to  FIG. 7  but with further elements removed to improve the view of the relevant illustrated elements;  
         [0029]      FIG. 8  is a rear elevational view of the embodiments of  FIGS. 2 and 3 ;  
         [0030]      FIG. 9  is an isometric view of a third embodiment of the energy recovery ventilator of the present invention installed directly on to a return air duct of a heating or cooling system;  
         [0031]      FIG. 10  is a rear perspective view of the embodiment of  FIG. 9 ;  
         [0032]      FIG. 11  is an enlarged fragmentary isometric view of the portion of  FIG. 10  indicated by curve  11 - 11  illustrating the use of a hinged bar mounting system;  
         [0033]      FIG. 12  is a side elevational view of the embodiment of  FIG. 9  illustrating the use of a hinged bar mounting system;  
         [0034]      FIG. 13  is a rear elevational view of the embodiment of  FIG. 9 ;  
         [0035]      FIG. 14  is an isometric view of a fourth embodiment of the energy recovery ventilator of the present invention installed directly on to a return air duct of a heating or cooling system;  
         [0036]      FIG. 15 a  rear perspective view of the embodiment of  FIG. 14 ;  
         [0037]      FIG. 16  is an enlarged fragmentary isometric view of the portion of  FIG. 15  indicated by line  16 - 16  illustrating the use of a hinged bar mounting system;  
         [0038]      FIG. 17  is a side elevational view of the embodiment of  FIG. 14  illustrating the use of a hinged bar mounting system;  
         [0039]      FIG. 18  is a rear elevational view of the embodiment of  FIG. 14 ;  
         [0040]      FIG. 19  is an isometric view of a fifth embodiment of the energy recovery ventilator of the present invention installed on an exterior wall;  
         [0041]      FIG. 20  is a side elevational view, partially in section, of the energy recovery ventilator of  FIG. 19  illustrating the use of a through-the-wall accessory kit;  
         [0042]      FIG. 21  is an exploded perspective view of the through-the-wall accessory kit;  
         [0043]      FIG. 22  is an electrical schematic of the control system for the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0044]     Referring again to the drawings,  FIGS. 2, 3 ,  9  and  14  are isometric views of first, second, third and fourth embodiments of the present invention installed on a return air duct  14  of a heating or cooling system  12 . In each of  FIGS. 2, 3 ,  9 , and  14 , the energy recovery ventilator is shown as part of a ventilation system including a heating or cooling system  12 , a heating or cooling mechanism  13 , and a duct system including a return air duct  14 .  FIG. 2  shows a first embodiment, wherein the housing  10  is installed in a parallel orientation on the bottom of a horizontal section  16  of the return air duct  14 .  FIG. 3  shows a second embodiment, wherein the housing  10  is installed in a parallel orientation on the side of a vertical section  18  of a return air duct  14 .  FIG. 9  shows a third embodiment, wherein the housing  10  is installed in a perpendicular orientation on the bottom of a horizontal section  16  of a return air duct  14 .  FIG. 14  shows a fourth embodiment, wherein the housing  10  is installed in a parallel orientation on the side of a horizontal section  16  of a return air duct  14 . In each of  FIGS. 2, 3 ,  9  and  14 , the energy recovery ventilator is shown in phantom before being swung into position for installation.  
         [0045]     In  FIGS. 2, 3 ,  9  and  14 , a first air flow opening  30  and a second air flow opening  32  are shown in the first face panel  38  of the housing  10 , a third air flow opening  34  is shown in the third face panel  42  of the housing  10 , and a fourth air flow opening  36  is shown in the fourth face panel  44  of the housing  10 . The first air flow opening  30  and the second air flow opening  32  are in direct communication with the stale air space of the return air duct  14 . The third air flow opening  34  and the fourth air flow opening  36  are fitted with duct collar connections  28 . The third air flow opening  34  is connected to an intake duct pipe  58  for communication with a fresh air space (not shown). The fourth air flow opening  36  is connected to an exhaust duct pipe  60  for communication with a fresh air space (not shown).  
         [0046]     Stale room air enters the housing  10  directly from the return air duct  14  through the first air flow opening  30 . Outside air enters the housing  10  from the intake duct  58  through the third air flow opening  34 . Fresh air exits the housing  10  directly into the return air duct  14  through the second air flow opening  32 . Exhaust room air exits the housing  10  to an exhaust duct pipe  60  through the third air flow opening  34 . The hinged bar mounting system  62  is shown on the fifth face panel  46  of the housing  10  in  FIGS. 2 and 3  and on the first face panel  38  of the housing  10  in  FIGS. 9 and 14 . Once the hinged bar mounting system  62  is engaged, the housing  10  is rotated into position as shown.  
         [0047]      FIGS. 4, 5 ,  12  and  17  further illustrate the hinged bar mounting system  62 . A first hinge bracket  64  is shown removably fastened to the return air duct  14 , a second hinge bracket  66  is shown removably fastened to the fifth face panel  46  of the housing  10  in  FIGS. 4 and 5  and to the first face panel  38  of the housing  10  in  FIGS. 12 and 17 . The first and second hinge brackets  64 ,  66  are engaged. The housing  10  is positioned in an orientation necessary to engage the hinge brackets  64 ,  66  and secure the housing  10  to the return air duct  14 . The housing  10  is then rotated into the mounting position as shown. The housing  10  is removably fastened to the return air duct  14  with screws  68  and fastening brackets  70 .  
         [0048]      FIG. 4A  is an enlarged fragmentary exploded view of a portion of  FIG. 4  further illustrating the hinged bar mounting system  62 . The first hinge bracket  64  is removably fastened to the return air duct  14  and the second hinge bracket  66  is removably fastened to the fifth face panel  46  of the housing  10 . The housing  10  is oriented to a position that will allow the hinge brackets  64 ,  66  to engage, as shown in  FIG. 4 .  
         [0049]      FIGS. 6, 10  and  15  are rear isometric views further illustrating the present invention.  FIGS. 6, 10  and  15  show the first air flow opening  30  and the second air flow opening  32  in the first face panel  38  of the housing  10 , and the fourth air flow opening  36  in the fourth face panel  44  of the housing  10 . A gasket assembly  61  is shown on the first face panel  38  around the first and second air flow openings  30 ,  32 . The fourth air flow opening  36  is fitted with a duct collar connection  28 . The first hinge bracket  64  is removably fastened to the return air duct  14 , and the second hinge bracket  66  is removably fastened to the fifth face panel  46  of the housing  10  in  FIG. 6  and to the first face panel  38  of the housing  10  in  FIGS. 10 and 15 . The first and second hinge brackets  64 ,  66  are engaged and the gasket assembly  61  is flush with the return air duct  14 . Fittings  72  for a control system (not shown) are also shown in the fourth face panel  44  of the housing  10 . Outside air from the fresh air space (not shown) enters the housing  10  from an intake duct pipe  58  connected to the third air flow opening (not shown). Stale room air enters the housing  10  directly from the return air duct  14  through the first air flow opening  30 . Exhaust room air exits the housing  10  through the third air flow opening  34  to an exhaust duct pipe  60  for delivery to the fresh air space (not shown). Fresh air exits the housing  10  directly into the return air duct  14  through the second air flow opening  32 .  
         [0050]      FIGS. 7, 7A ,  11  and  16  are enlarged fragmentary views illustrating the hinged bar mounting system  62 . The first hinge bracket  64  is removably fastened to the return air duct  14  with screws  68 , and the second hinge bracket  66  is removably fastened to the fifth face panel  46  of the housing  10  in  FIGS. 7 and 7 A and to the first face panel  38  of the housing  10  in  FIGS. 11 and 16  with screws  68 . The first and second hinge brackets  64 ,  66  are engaged.  
         [0051]      FIGS. 8, 13  and  18  are rear elevational views illustrating the present invention.  FIGS. 8, 13  and  18  show the housing  10  including the heat exchange device  20 . The heat exchange device  20  comprises a diamond-shaped plate-type heat exchanger  22  like that described in U.S. Pat. No. 5,660,228, incorporated here by reference. The heat exchange device  20  further comprises a first fan  24  and a second fan  26  to induce air movement through the heat exchange device  20 . Outside air from a fresh air space (not shown) enters the housing  10  from an intake duct pipe  58  connected to the third air flow opening  34 . Stale room air enters the housing  10  directly from the return air duct  14  through the first air flow opening  30 . The outside air stream  50  and the stale room air stream  52  pass through the heat exchanger  22 , after which the outside air stream  50  becomes a fresh air stream  56  and the stale room air stream  52  becomes an exhaust room air stream  54 . The fresh air stream  56  then travels through the first fan  24  and exits the housing  10  directly into the return air duct  14  through the second air flow opening  32 . The exhaust room air stream  54  travels through the second fan  26  and exits the housing  10  through the third air flow opening  34  to an exhaust duct pipe  60  for delivery to a fresh air space (not shown). A control unit  77  for the control system (not shown) is also shown in the housing  10 .  
         [0052]      FIG. 19  shows an isometric view of a fifth embodiment of the present invention, wherein the housing  10  is installed on a wall  74 . A first air flow opening  30  and a second air flow opening  32  are shown in the first face panel  38  of the housing  10 , a third air flow opening  34  is shown in the third face panel  42  of the housing, and a fourth air flow opening  36  is shown in the fourth face panel  44  of the housing  10 . The first air flow opening  30  and the second air flow opening  32  are in direct communication with the fresh air space of the outdoors  11  on the exterior of the wall  74 . The third air flow opening  34  and the fourth air flow opening  36  are fitted with duct collar connections  28 . The third air flow opening  34  is connected to an intake duct pipe  58  for communication with a stale air space (not shown). The fourth air flow opening  36  is connected to an exhaust duct pipe  60  for communication with a stale air space (not shown).  
         [0053]     Outside air enters the housing  10  directly from the outdoors  11  through the first air flow opening  30 . Stale room air from the stale air space (not shown) enters the housing  10  from the intake duct pipe  58  through the third air flow opening  34 . Exhaust room air exits the housing  10  directly into the outdoors  11  through the second air flow opening  32 . Fresh air exits the housing  10  through the third air flow opening  34  to an exhaust duct pipe  60  for delivery to a stale air space (not shown). Once the hinged bar mounting system  62  is engaged, the housing  10  is rotated into position as shown.  
         [0054]      FIGS. 20 and 21  illustrate the use of one embodiment of a through-the-wall accessory kit  76  to pass the air streams  50 ,  54  through the wall. An interior plate  78  having a first opening  79  and a second opening  80  is connected to the housing  10  so that the first opening  79  in the interior plate  78  is in-line with the first air flow opening  30  and the second opening  80  in the interior plate  78  is in-line with the second air flow opening  32 . The interior plate  78  is then connected to the interior of the wall  74 . A first wall insert  81  is connected to the interior plate  78  in-line with the first opening  79  and installed through the wall  74 . A second wall insert  82  is connected to the interior plate  78  in-line with the second opening  80  and installed through the wall  74 . A first weather hood  83  is installed on the exterior of the wall  74  and connected to the first wall insert  81 , and a second weather hood  84  is installed on the exterior of the wall  74  and connected to the second wall insert  82 . Screens  90  may also be installed in the weather hoods  83 ,  84 .  
         [0055]      FIG. 22  is an electrical schematic illustrating a preferred embodiment of the control system  73  of the invention. In this embodiment, the control system  73  operates a motor  85  by means of a relay  87 . In turn, motor  85  operates the first and second fans  24 ,  26  in the heat exchange device  20 . The control system  73  operates the motor  85  a portion of each hour based on the desired ventilation and the air flow capacity of the unit. In the preferred embodiment, the amount of each hour the control system  73  operates the motor  85  can be adjusted by any suitable adjustable control, such as a potentiometer  92 . For maximum ease of installation, control system  73  preferably includes a plug  88  capable of being plugged into a conventional electrical receptacle (not shown). The control system  73  also has the capability to control the heating or cooling system  12 , by means of relay  87  having a second set of relay contacts  89  conductively connected to connectors  91  which, once connected properly, operate the heating or cooling system blower (not shown) concurrently with the motor  85 .  
         [0056]     While the invention has been described with reference to preferred embodiments, those skilled in the art will appreciate that certain substitutions, alterations and omissions may be made to the embodiments without departing from the spirit of the invention. Accordingly, the foregoing description is meant to be exemplary only, and should not limit the scope of the invention.