Title:
Energy recovery ventilator
Kind Code:
A1


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.



Inventors:
Gates, Charles (Madison, WI, US)
Steege, Douglas (Madison, WI, US)
Friedlander, Matthew L. C. (Madison, WI, US)
Application Number:
10/738970
Publication Date:
06/23/2005
Filing Date:
12/17/2003
Assignee:
RenewAire, LLC
Primary Class:
International Classes:
F24F12/00; F28F13/06; (IPC1-7): F28F13/06
View Patent Images:



Primary Examiner:
DUONG, THO V
Attorney, Agent or Firm:
QUARLES & BRADY LLP (MAD) (Milwaukee, WI, US)
Claims:
1. An energy recovery ventilator comprising: 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; a fourth air flow opening in the housing; and wherein the first air flow opening and the second air flow opening are capable of being in direct communication with either a return air duct for a heating or cooling system or a fresh air space.

2. The energy recovery ventilator of claim 1, wherein the housing also has a second face panel opposite the first face panel, a third face panel, a fourth face panel opposite the third face panel, a fifth face panel, and a sixth face panel opposite the fifth face panel.

3. The energy recovery ventilator of claim 2, wherein the third air flow opening is located in the third face panel and the fourth air flow opening is located in the fourth face panel.

4. The energy recovery ventilator of claim 1, wherein 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.

5. The energy recovery ventilator of claim 4, wherein the third air flow opening is in communication with a 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 a fresh air space to deliver exhaust room air to the fresh air space through an exhaust duct pipe.

6. The energy recovery ventilator of claim 1, wherein the fresh air space is the outdoors.

7. The energy recovery ventilator of claim 1, wherein 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.

8. The energy recovery ventilator of claim 7, wherein the third air flow opening is in communication with a 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.

9. The energy recovery ventilator of claim 1, wherein the housing further includes a hinged bar mounting system, the hinged bar mounting system including a first hinge bracket removably fastened to a mounting surface and a second hinge bracket removably fastened to the housing.

10. The energy recovery ventilator of claim 9, wherein the mounting surface is the return air duct.

11. The energy recovery ventilator of claim 9 wherein the mounting surface is a wall.

12. The energy recovery ventilator of claim 9, wherein the first hinge bracket is shaped to engageably receive the second hinge bracket.

13. The energy recovery ventilator of claim 12, wherein the first hinge bracket and the second hinge bracket engage to support the energy recovery ventilator on the mounting surface.

14. The energy recovery ventilator of claim 1, wherein the energy recovery ventilator can be installed in a perpendicular orientation on a bottom surface of a horizontal section of the return air duct of a heating or cooling system.

15. The energy recovery ventilator of claim 1, wherein the energy recovery ventilator can be installed in a parallel orientation on a bottom surface of a horizontal section of the return air duct of a heating or cooling system.

16. The energy recovery ventilator of claim 1, wherein the energy recovery ventilator can be installed in a parallel orientation on a side surface of a horizontal section of a return air duct of a heating or cooling system.

17. The energy recovery ventilator of claim 1, wherein the energy recovery ventilator can be installed in a parallel orientation on a vertical section of a return air duct of a heating or cooling system.

18. The energy recovery ventilator of claim 1, wherein the energy recovery ventilator can be installed on a wall.

19. The energy recovery ventilator of claim 18, wherein the energy recovery ventilator is installed on a wall using a through-the-wall accessory kit.

20. The energy recovery ventilator of claim 1, wherein the energy recovery ventilator further comprises a control system.

21. The energy recovery ventilator of claim 20, wherein the control system is a built-in control system including a plug-in power source.

22. The energy recovery ventilator of claim 21, wherein the control system operates the energy recovery ventilator for a portion of each hour.

23. The energy recovery ventilator of claim 21, wherein the control system can be wired to a control system for the heating or cooling system to operate a heating or cooling system blower concurrently with the energy recovery ventilator.

24. An energy recovery ventilator for a heating or cooling system, the energy recovery ventilator comprising: a housing having at least a first face panel; a heat exchange device supported in the housing; a stale room air inlet in the first face panel of the housing, the stale room air inlet being in direct communication with a return air duct in a heating or cooling system to receive stale room air from the return air duct; a fresh air outlet in the first face panel of the housing, the fresh air outlet being in direct communication with a return air duct in a heating or cooling system to deliver fresh air to the return air duct; an outside air inlet in the housing, the outside air inlet being in communication with a fresh air space to receive outside air from the fresh air space through an intake duct pipe; and an exhaust room air outlet in the housing, the exhaust room air outlet being in communication with a fresh air space to deliver exhaust room air to the fresh air space through an exhaust duct pipe.

25. The energy recovery ventilator of claim 24, wherein the housing also has a second face panel opposite the first face panel, a third face panel, a fourth face panel opposite the third face panel, a fifth face panel, and a sixth face panel opposite the fifth face panel.

26. The energy recovery ventilator of claim 24, wherein the outside air inlet is located in the third face panel and the exhaust room air outlet is located in the fourth face panel.

27. The energy recovery ventilator of claim 24, wherein the housing further includes a hinged bar mounting system, the hinged bar mounting system including a first hinge bracket removably fastened to the return air duct for the heating or cooling system and a second hinge bracket removably fastened to the housing.

28. The energy recovery ventilator of claim 27, wherein the first hinge bracket is shaped to engageably receive the second hinge bracket.

29. The energy recovery ventilator of claim 28, wherein the first hinge bracket and the second hinge bracket engage to support the energy recovery ventilator on the return air duct.

30. The energy recovery ventilator of claim 24, wherein the energy recovery ventilator can be installed in a perpendicular orientation on a bottom surface of a horizontal section of the return air duct of the heating or cooling system.

31. The energy recovery ventilator of claim 24, wherein the energy recovery ventilator can be installed in a parallel orientation on a bottom surface of a horizontal section of the return air duct of the heating or cooling system.

32. The energy recovery ventilator of claim 24, wherein the energy recovery ventilator can be installed in a parallel orientation on a side surface of a horizontal section of the return air duct of the heating or cooling system.

33. The energy recovery ventilator of claim 24, wherein the energy recovery ventilator can be installed in a parallel orientation on a vertical section of the return air duct of the heating or cooling system.

34. The energy recovery ventilator of claim 24, wherein the energy recovery ventilator further comprises a control system.

35. The energy recovery ventilator of claim 34, wherein the control system is a built-in control system having a plug-in power source.

36. The energy recovery ventilator of claim 34, wherein the control system operates the energy recovery ventilator for a portion of each hour.

37. The energy recovery ventilator of claim 34, wherein the control system can be wired to a control system for the heating or cooling system to operate a heating or cooling system blower concurrently with the energy recovery ventilator.

38. A ventilation system for a building, the ventilation system comprising: a heating or cooling system having a heating or cooling mechanism, a blower to induce air movement through the heating or cooling system, and a duct system having a return air duct; an energy recovery ventilator installed directly on to the return air duct; and wherein the energy recovery ventilator includes 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 being in direct communication with the return air duct.

39. The ventilation system of claim 38, wherein 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.

40. The ventilation system of claim 39, wherein 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.

41. The ventilation system of claim 3 8, wherein the ventilation system further comprises a control system that operates the heating or cooling system blower concurrently with the energy recovery ventilator.

42. A method for installing an energy recovery ventilator on a return air duct of a heating or cooling system, the method comprising the steps of: (a) removably connecting a hinge bracket on the energy recovery ventilator to a correspondingly engageable hinge bracket on the return air duct; (b) rotating the energy recovery ventilator into a mounting position; and (c) removably fastening the energy recovery ventilator to the return air duct;

43. The method of claim 42, further comprising the steps of: (d) attaching a first duct pipe to the energy recovery ventilator; and (e) attaching a second duct pipe to the energy recovery ventilator.

44. The method of claim 42, wherein step (a) includes attaching the return air duct hinge bracket to the return air duct and attaching the energy recovery ventilator hinge bracket to the energy recovery ventilator.

45. The method of claim 42, wherein step (c) includes 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.

Description:

BACKGROUND OF THE INVENTION

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.

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.

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.

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.

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.

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).

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.

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

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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

FIG. 1 is rear elevational view of one embodiment of a prior art energy recovery ventilator;

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;

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;

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;

FIG. 4A is an enlarged fragmentary exploded view of a portion of FIG. 4 illustrating the use of a hinged bar mounting system;

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;

FIG. 6 is a rear isometric view of the embodiments of FIGS. 2 and 3;

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;

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;

FIG. 8 is a rear elevational view of the embodiments of FIGS. 2 and 3;

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;

FIG. 10 is a rear perspective view of the embodiment of FIG. 9;

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;

FIG. 12 is a side elevational view of the embodiment of FIG. 9 illustrating the use of a hinged bar mounting system;

FIG. 13 is a rear elevational view of the embodiment of FIG. 9;

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;

FIG. 15 a rear perspective view of the embodiment of FIG. 14;

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;

FIG. 17 is a side elevational view of the embodiment of FIG. 14 illustrating the use of a hinged bar mounting system;

FIG. 18 is a rear elevational view of the embodiment of FIG. 14;

FIG. 19 is an isometric view of a fifth embodiment of the energy recovery ventilator of the present invention installed on an exterior wall;

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;

FIG. 21 is an exploded perspective view of the through-the-wall accessory kit;

FIG. 22 is an electrical schematic of the control system for the present invention.

DETAILED DESCRIPTION OF THE INVENTION

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.

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).

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.

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.

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.

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.

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 7A 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.

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.

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).

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.

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.

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.

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.