CA3050898A1 - Heat recovery device - Google Patents

Abstract

A heat recovery device for use on a clothes dryer includes a body having a main passageway. The body has a first end and a second end and a dryer exhaust coupling proximate to the first end. The first end has a main flow inlet and the second end has a main flow outlet. The heat recovery device also includes a return air conduit coupled to the body. The return air conduit has a return air inlet and a return air outlet. The return air inlet is disposed within the main passageway and facing the main flow inlet. The dryer exhaust coupling is configured to be removably coupled to a dryer exhaust outlet of a clothes dryer. The return air inlet is configured to receive a portion of the exhaust air discharged from the clothes dryer and discharge that portion through the return air outlet.

Description

HEAT RECOVERY DEVICE
Technical Field [0001] The present invention relates to a heat recovery device for use with a clothes dryer.
Background

[0002] Electric and gas heated clothes dryers have become common household appliances during the past several decades for drying wet clothes inside a building, such as a house. As part of the typical clothes drying process, the clothes dryer produces hot air. The hot air flows through the wet clothes and is then exhaust to the exterior of the house by way of an exhaust vent. The practice of venting this hot exhaust air outside is particularly inefficient and results in wasted energy, which may result in increased operating costs, especially in recent years with the rapid rise in energy costs for homeowners. There are several problems, however, associated with simply venting the hot exhaust air from the clothes dryer directly back into the interior of the house which is why the conventional practice is to vent the exhaust air to the exterior of the house. For example, the hot exhaust air from the dryer typically contains a certain amount of moisture and lint picked up from the clothes being dried. As a result, it is undesirable to re-circulate the hot exhaust air into the interior of the house or even back into the dryer.

[0003] What is needed, therefore, is a device and method for recovering at least some of the driest hot air that would otherwise be exhausted to the exterior of the house and redirecting that hot air either back into the house or even the clothes dryer.

Summary

[0004] A heat recovery device for use on a clothes dryer includes a body having a main passageway with a central axis. The body has a first end and a second end and a dryer exhaust coupling proximate to the first end. The first end has a main flow inlet and the second end has a main flow outlet. The heat recovery device also includes a return air conduit coupled to the body. The return air conduit has a return air inlet and a return air outlet. The return air inlet is disposed within the main passageway and facing the main flow inlet. The dryer exhaust coupling is configured to be removably coupled to a dryer exhaust outlet of a clothes dryer such that the exhaust air discharged from the clothes dryer flows into the main flow inlet.
The return air inlet is configured to receive a portion of the exhaust air discharged from the clothes dryer and discharge that portion through the return air outlet and a remainder of the exhaust air being discharged through the main flow outlet.

[0005] In one embodiment, when the heat recovery device is coupled to the dryer exhaust outlet, the central axis is substantially horizontal. In this embodiment, the return air outlet is configured to discharge the portion of the exhaust air from the clothes dryer in a direction substantially perpendicular to the central axis.

[0006] The return air inlet has a cross-section that is one of circular, semi-circular, elliptical, rectangular, square, or triangular.

[0007] In one embodiment, the return air inlet is disposed in an upper half of the main passageway.

[0008] In another embodiment, a heat recovery device for use on a clothes dryer, includes a body having a main passageway with a central axis. The body has a first end and a second end and a dryer exhaust coupling proximate to the first end.
The first end has a main flow inlet and the second end has a main flow outlet. The heat recovery device also includes a return air conduit integrally formed to the body. The return air conduit has a return air inlet and a return air outlet. The return air inlet is disposed within the main passageway and faces the main flow inlet and the return air outlet is disposed outside the main passageway. The body and the return air conduit are comprised of a first half and a second half separable from each other along a plane extending through the central axis. The dryer exhaust coupling is configured to be removably coupled to a dryer exhaust outlet of a clothes dryer such that the exhaust air discharged from the clothes dryer flows into the main flow inlet.
The return air inlet is configured to receive a portion of the exhaust air discharged from the clothes dryer and discharge that portion through the return air outlet and a remainder of the exhaust air is discharged through the main flow outlet. In one embodiment, a portion of the return air conduit external to the body has a T-shaped profile. When the heat recovery device is coupled to the dryer exhaust outlet, the central axis may be substantially horizontal. In that configuration, the return air outlet is configured to discharge the portion of the exhaust air from the clothes dryer in a direction substantially perpendicular to the central axis.

[0009] In one embodiment, the heat recovery device further includes one connector affixed to the body and one connector affixed to the return air conduit.
Each connector is configured to couple together the first half and the second half.

[0010] In another embodiment, the return air conduit includes a cover with openings and the cover is coupled to the return air outlet. The cover may be slideably removable from the return air outlet and the openings may be elongated slots. The return air conduit may include openings on at least one side of the return air conduit. The return air inlet may have a semi-circular cross-section and the return air inlet is disposed in an upper half of the main passageway.

[0011] Other features of the heat recovery device are contemplated and described and claimed below.
Brief Description of the Drawings

[0012] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one or more exemplary embodiments of the invention and, together with the general description of the invention given above, and the detailed description of the embodiments given below, serve to explain the embodiments of the invention.

[0013] Fig. 1 is side elevational view of the heat recovery device installed on a clothes dryer according to one embodiment of the invention.

[0014] Fig. 2 is a perspective view of the heat recovery device of Fig.
1.

[0015] Fig. 3 is a cross-sectional view of the heat recovery device of Fig. 2 taken along line 3-3.

[0016] Fig. 4 is a perspective view of a heat recovery device according to another embodiment of the invention.

[0017] Fig. 5 is a cross-sectional view of the heat recovery device of Fig. 4 taken along line 5-5.

[0018] Fig. 6 is a perspective view of a heat recovery device according to another embodiment of the invention.

[0019] Fig. 7 is a cross-sectional view of the heat recovery device of Fig. 6 taken along line 7-7.

[0020] Fig. 8 is a perspective view of a heat recovery device according to another embodiment of the invention.

[0021] Fig. 9 is a cross-sectional view of the heat recovery device of Fig. 8 taken along line 9-9.

[0022] Fig. 10 is a front prospective view of a heat recovery device according to another embodiment of the invention.

[0023] Fig. 11 is rear prospective view of the heat recovery device of Fig. 10.

[0024] Fig. 12 is a cross-sectional perspective view of the heat recovery device of Fig. 10 taken along line 12-12 with the cover slid partially out.

[0025] Fig. 13 is a front elevational view of the heat recovery device of Fig. 10.

[0026] Fig. 14 is a partial cross-sectional perspective view of the heat recovery device of Fig. 10

[0027] Fig. 15 is a side elevational view of a clothes dryer exhausting dryer air to the exterior of a building.

[0028] Fig. 16 is a side elevational view of a clothes dryer exhausting dryer air to the interior of a building.

[0029] Fig. 17 is a cross-sectional view of the heat recovery device of Fig. 2 with the inlet port located near the middle of the main passageway.

[0030] Fig. 18 is a cross-sectional view of the heat recovery device of Fig. 2 with the inlet port located near the bottom of the main passageway.
Detailed Description

[0031] The invention is intended to return heat, in the form of hot air, that is normally exhausted from a conventional clothes dryer to the exterior of a building, such as a house, and into the environment. According to one aspect of the invention, at least some of the hot air may be returned to the interior of the house, such as into the room where the clothes dryer is located, to heat at least part of the interior of the house. According to another aspect of the invention, at least some of the hot air may be returned back into the clothes dryer to enhance the drying efficiency of the clothes dryer. According to one aspect of the invention, little or none of the moisture and lint which may be entrained in the exhausted hot air from the clothes dryer is returned to the interior of the house or the clothes dryer.

[0032] With reference to Fig. 1, an exemplary laundry room 10 with a conventional clothes dryer 12 is illustrating venting hot exhaust air from the clothes dryer 12 to the exterior of a building 14, such as a house. A heat recovery device 20 according to one exemplary embodiment is shown coupled at one end to a dryer exhaust outlet 22 of the clothes dryer 12 and coupled at another end to an exhaust duct 24 which is routed through an exterior wall 26 of the building 14. Hot exhaust air 28 flowing through the exhaust duct 24 exits through a vent 30. A conduit 32, such as pipe or tube, is coupled to the heat recovery device 20. According to an aspect of the invention, return hot air 34 exits the conduit 32 into the interior of the house 14 as illustrated in Fig. 1. Alternatively, return hot air 34 may also exit into the clothes dryer 12 instead of the interior of the house 14 according to another aspect of the invention.

[0033] Various embodiments of heat recovery devices are shown in Figs. 2-12.
Some features of the various embodiments of the heat recovery devices in Figs.

12 are the same or nearly the same. Consequently, the same reference number for such a feature will be used on each embodiment where appropriate.

[0034] The heat recovery device 20 is further illustrated in Figs. 2 and 3. The heat recovery device 20 is comprised of a body 40 having a main passageway 42 with a main flow inlet 44 and main flow outlet 46. The main flow inlet 44 includes a dryer exhaust coupling 48, which is configured to be coupled in sealing engagement to the dryer exhaust outlet 22 of the clothes dryer 12. The exhaust duct 24 is coupled in sealing engagement with the main flow outlet 46 of the heat recovery device 20. The heat recovery device 20 further includes a return air conduit having a return air inlet 52 and a return air outlet 54, which is in sealing engagement with the conduit 32. The return air inlet 52 is positioned in the main passageway 42, and more particularly, near the top of the main passageway 42. The return air conduit 50 and its return air inlet 52 and return air outlet 54 have a generally circular cross-section, but could have other cross-sectional shapes as will be discussed below.

[0035] With specific reference to Fig. 2, the flow path of the hot exhaust air from the clothes dryer 12 through the heat recovery device 20 is illustrated. Hot exhaust air being discharged from the dryer exhaust outlet 22 flows into the main flow inlet 44 and into the main passageway 42 as schematically indicated by arrow A. A
portion of the hot exhaust air exits through the main flow outlet 46 as schematically indicated by arrow B. The remainder of the hot exhaust air exits through the return air outlet 54 as schematically indicated by arrow C.

[0036] As shown in Figs. 2 and 3, the body 40 of the heat recovery device 20 is cylindrical in shape, and sized such that the dryer exhaust coupling 48 and body 40 have similar cross-sectional areas compared to the dryer exhaust outlet 22.
However, the body 40 and the dryer exhaust coupling 48 of the heat recovery device 20 are not limited to these shapes. The dryer exhaust coupling 48 may be threaded or may be sized to produce a frictional or interference fit with the dryer exhaust outlet 22 of the clothes dryer 12 to couple in sealing engagement with the dryer exhaust coupling 48 of the heat recovery device 20. Similarly, the main flow outlet 46 of the heat recovery device 20 may be sized to produce a frictional or interference fit with the exhaust duct 24. It will be appreciated that tape, a pipe clamp, zip ties, screws, rivets, or other mechanical fasteners may be used to couple the heat recovery device 20 to the dryer exhaust outlet 22 and the exhaust duct 24. In one embodiment (Fig. 5), the heat recovery device 20 is constructed of polyvinyl chloride (PVC), but it may be constructed of any other suitable plastic, rubber, carbon-fiber, metal, or any other suitable material. Moreover, the components of the heat recovery device 20 may each be constructed of different materials as operating conditions warrant. For example, the body 40 may be constructed of PVC while the return air conduit 50 may be constructed of metal.

[0037] The return air inlet 52 of the heat recovery device 20 in Figs. 2 and 3 has a circular cross-section with a diameter which is smaller than the diameter of the circular cross-section of the main passageway 42 of the body 40. In the embodiment in Fig. 3, the diameter of return air inlet 52 is a little more than one-third the diameter of main passageway 42 of the body 40. By way of example, but not a limitation, the diameter of return air inlet 52 may range from between one-tenth to three-quarters of the diameter of the main passageway 42 of the body 40. The size and location of the return air inlet 52 may be dictated by how much moist air is desired to be directed back into the laundry room 10. For instance, someone in drier climates may want more of the moist air directed back into the interior of the house 14. To that end, a larger return air inlet 52 positioned lower in the body 40 may likely return more moist air back into the interior of the house 14 and a smaller return air inlet 52 positioned at the top of the main passageway 42 of the body 40 may likely return less moist air back into the interior of the house 14.

[0038] In the embodiment of the heat recovery device 20 shown in Figs. 2 and 3, the return air inlet 52 is sized to remain in the upper half of the main passageway 42 of the body 40 to capture the dry hot air while the moist air and lint particulates pass under return air inlet 52 and are exhausted to the exterior of the building 14 via the exhaust duct 24. It is believed that placing the return air inlet 52 in the upper-half of the main passageway 42 of the body 40 will return the driest air from the dryer exhaust outlet 22 back into the laundry room 10. In addition, the force of the exhaust airstream exiting from the exhaust outlet 22 is adequate to separate and return the dry air via the return air conduit 50 into the laundry room 10. As a result, no additional energy is consumed to recover the dry air from the exhaust stream.

[0039] Different shapes and configurations of the return air inlet 52 of the return air conduit 50 would be apparent to one skilled in the art in order to alter the amount of warm air recovered. As such, the shapes and configurations are not limited to the shapes and configurations disclosed herein. In one embodiment shown in Figs. 4 and 5, the heat recovery device 20 includes a return air conduit 60 with a return air inlet 62 having a flat surface 64 located in the upper-half of the main passageway 42 of the body 40 and just below where the return air conduit 60 intersects with the body

40. The flat surface 64 may be located at different positions relative to the top of the main passageway 42 of the body 40 to change the amount of hot air returned to laundry room 10 via conduit 32. The closer the flat surface 64 is to the top of the main passageway 42 of the body 40 (e.g., around 25% of the diameter of the main passageway 42 from the top), the less hot air that may be directed into the interior of the laundry room 10. Conversely, the further the flat surface 64 is from the top of the main passageway 42 body 40 (e.g., around 75% of the diameter of the main passageway 42 from the top) the warmer air may be directed into the interior of the laundry room 10. The flat surface 64 is shown mounted to the sidewalls of the main passageway 42 of the body 40 with a flat, half-moon shaped back portion 66, curved to couple it to the upper-half of the main passageway 42.
[0040] In another embodiment shown in Figs. 6 and 7, the heat recovery device 20 includes a return air conduit 70 with a return air inlet 72 that has an elliptical cross-section. The upper-half of the elliptical cross-section of the return air inlet 72 generally mimics the shape of the main passageway 42 of the body 40 of the heat recovery device 20.

[0041] In yet another embodiment shown in Figs. 8 and 9, the heat recovery device 20 includes a return air conduit 80 with a return air inlet 82 that has a rectangular cross-section. The return air inlet 82 may also have a square cross-section. In another embodiment, the cross-section of the return air inlet may have triangular cross section.

[0042] Another embodiment of a heat recovery device 90 is shown in Figs. 10-14.
The heat recovery device 90 is comprised of a body 92 having a main passageway 94 with a main flow inlet 96 and a main flow outlet 98. The main flow inlet 96 includes a dryer exhaust coupling 100 formed from a series of tabs 102, which are configured to be coupled in sealing engagement to the dryer exhaust outlet 22 of the clothes dryer 12. The tabs 102 may be flexible to allow the dryer exhaust coupling 100 to slip over the dryer exhaust outlet 22 to produce a frictional or interference fit.
It will be appreciated that tape, a pipe clamp, zip ties, screws, rivets, or other mechanical fasteners may be used to couple the heat recovery device 90 to the dryer exhaust outlet 22 and the exhaust duct 24. The heat recovery device 90 further includes a return air conduit 104 having a return air inlet 106 and a return air outlet 108. In one embodiment, the return air conduit 104 is integrally formed with the body 40. While the return air inlet 106 shown in Fig. 13 has a semi-circular cross-section, other cross-sectional geometries may be used, including but not limited to circular, elliptical, rectangular, square, or triangular. While the portion of the return air conduit 104 that is external to the body 92 has a generally T-shaped profile as seen in Fig. 13, other profiles may be implemented. The return air outlet 108 has a generally rectangular shape with a slidable cover 110 with openings 112, such as elongated slots, fit thereover. The cover 110 may be slid partially off or completely removed the return air outlet 108 so that the interior of the return air conduit 104 may be cleaned or to allow greater airflow through the return air outlet 108. The return air conduit 104 has opposing sides 114, 116, with openings 118, such as elongated slots. The slots 112 and the slots 118 are configured to allow return hot air flow through them. It will be appreciated that the return air outlet 108 may have other shapes such a square or circular, for example. It will be further appreciated that through holes and other types of openings may be used in place of the slots 112 and/or the slots 118 to allow return hot air to flow through them. As shown in Fig. 13, the bottom of the return air inlet 106 is located approximately one-third of the diameter of the main passageway 94 from the top of the main passageway 94. In other words, the return air inlet 106 is disposed within the upper portion of the main passageway 94.

[0043] With specific reference to Fig. 10, the flow path of the hot exhaust air from the clothes dryer 12 through the heat recovery device 90 is illustrated. Hot exhaust air flows through the main flow inlet 96 and into the main passageway 94 as indicated by arrow A. A portion of the hot exhaust air exits through the main flow outlet 98 as indicated by arrow B. A portion of the hot exhaust air exits through the return air outlet 108, and more specifically through the slots 112 of the cover 110, as indicated by arrow C. A portion of the hot exhaust air exits through the slots 118 in opposing sides 114, 116, as indicated by arrows D. Unlike the embodiments illustrated in Figs. 2-9, the return air conduit 104 is not connected to a conduit, such as conduit 32, to direct the return hot air into the laundry room 10. Instead, the return hot air enters the laundry room 10 immediately after exiting through the slots 112, 118.

[0044] In an exemplary embodiment, the heat recovery device 90 may be constructed of two, separate halves 120, 122, which are held together by three connectors 124, two on the return air conduit 104 (Figs. 10, 11) and one on the bottom of body 92 (Figs. 13, 14). In one embodiment, the two halves 120, 122 are joined to each other along a plane extending through the central axis of the main passageway 94. Each connector 124 includes a flexible member 126 with a retaining member 128 at its distal end. The flexible member 126 is coupled to side 122 of the heat recovery device 90. A coupling member 130 is coupled to side of the heat recovery device 90. As the two halves 120, 122 are move toward each other, the retaining member 128 contacts the coupling member 130 and flexes away from the coupling member 130 as the two halves 120, 122 continue to be moved toward each other. As the two halves 120, 122 engage one another, the retaining member 128 moves past the coupling member 130 the flexible member 126 returns to it undeflected position and retaining member 128 engages the coupling member 130 to hold the two halves 120, 122 of the heat recovery device 90. It will be appreciated that other connectors may be used to hold the two halves 120, 122 together, such as screws, nuts and bolts, adhesive, glue, etc. It will also be appreciated that the body 92 of the heat recovery device 90 may be formed as a single, monolithic structure, i.e., as one piece.

[0045] Each embodiment of the heat recovery devices 20, 90 discussed above includes a main passageway 42, 94, which has a central axis. Advantageously, in practice, the heat recovery devices 20, 90 will be coupled to the clothes dryer 12 such that the central axes of the main passageways 42, 94 are substantially horizontal and each of the return air outlets 54, 108 discharge return air substantially perpendicular to the central axis in a substantially vertical direction.

[0046] As mentioned above, the position of the return air inlet in the main passageway is likely to influence the amount of moisture in the returned hot air being discharged into the laundry room. That is, the return air inlet may be positioned to collected drier air or positioned to collect moister air. To evaluate the position of the return air inlet on the amount of moist in the returned hot air, the inventor conducted five tests. The five tests were conducted to evaluate how the temperature and humidity inside a laundry room containing a conventional, electric residential clothes dryer changed under varying venting configurations. The five tests were conducted in a laundry room measuring 5 feet by 6 feet with the laundry room door closed.
Each test began with removing five beach towels from conventional, residential clothes washing machine after completing a normal wash cycle and placing them into the clothes dryer. The dryer was run for 30 minutes on the high heat setting. A
temperate and humidity monitor made by ACURITErm sitting directly on the top center of the dryer was used to measure temperature and humidity immediately before and immediately after the drying cycle. None of the dryer exhaust was diverted back into the dryer during any of the five tests.

[0047] In Test No. 1, the dryer exhaust was vented directly to the outside like a typical clothes dryer is usually set-up and operated as schematically illustrated in Fig. 15. That is, a heat recovery device of the type discussed above was not used and no dryer exhaust was intentionally diverted into the laundry room.

[0048] In Test No. 2, all of the dryer exhaust was vented directly into the laundry room as schematically illustrated in Fig. 16. In other words, nothing was attached to the dryer exhaust pipe.

[0049] In Test No. 3, the heat recovery device 20 similar to the one shown in Figs. 2 and 3 was used. The dryer exhaust coupling 48 of the heat recovery device 20 was attached to the dryer exhaust outlet 22 and the main flow outlet 46 of the heat recovery device 20 was attached to the exhaust duct 24 which was attached to the vent 30. The return air conduit 50 was positioned such that return air inlet 52 was in the most upwardly vertical position in the main passageway 42 of the body 40 of the heat recovery device 20 as illustrated in Fig. 3. In this configuration, a portion of the dryer exhaust exited through the vent 30 and a portion of the dryer exhaust exited the return air conduit 50 into the laundry room.

[0050] In Test No. 4, the heat recovery device 20 was connected to the clothes dryer in the same manner as in Test 3, but the return air conduit 50 was positioned such that the centerline of the return air inlet 52 was concentric with the centerline of the main passageway 42 of the body 40 of the heat recovery device 20 as illustrated in Fig. 17. Like Test No. 4, a portion of the dryer exhaust exited through the vent 30 and a portion of the dryer exhaust exited the return air conduit 50 into the laundry room.

[0051] In Test No. 5, the heat recovery device 20 was connected to the clothes dryer in the same manner as in Test 3, but the return air conduit 50 was positioned in the most vertically downward position in the main passageway 42 of the body 40 of the heat recovery device 20 as illustrated in Fig. 18. Again, a portion of the dryer exhaust exited through the vent 30 and a portion of the dryer exhaust exited the return air conduit 50 into the laundry room.

[0052] The table below summarizes the data that the temperate and humidity monitor collected during the five tests.
Test Test Starting Ending Temp. Starting Ending Humidity Comments No. Description Temp. Temp. Change Humidity Humidity Change (F) (F) (F) (%) (%) (%) 1 Typical 75 77 +2 45 46 +1 No visible connection moisture on walls or ceiling of laundry room 2 Venting 75 111 +36 42 99 +57 Walls directly to showed laundry visible MOM wetness.
Ceiling showed significant wetness, including beads of water.
3 Inlet port in 75 82 +7 45 49 +4 No visible top position moisture on walls or ceiling of laundry 4 Inlet port in 75 80 +5 43 53 +10 No visible middle moisture on position walls or ceiling of laundry MOM
Inlet port in 75 81 +6 41 57 +16 Slightly bottom visible position wetness on walls and ceiling.

[0053] When looking at the data from Test Nos. 3-5, Test No. 3 yielded the greatest temperature gain, a rise of 7 degrees, and the lowest increase in humidity, a rise of 4 percentage points. Test No. 5 yielded the highest increase in humidity, 16 percentage points.

[0054] While the present invention has been illustrated by a description of various preferred embodiments and while these embodiments have been described in some detail, it is not the intention of the inventor to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Thus, the various features of the invention may be used alone or in any combination depending on the needs and preferences of the user.

Claims (18)

WHAT IS CLAIMED IS:

1. A heat recovery device for use on a clothes dryer, comprising:
a body having a main passageway with a central axis, the body having a first end and a second end and a dryer exhaust coupling proximate to the first end, the first end having a main flow inlet and the second end having a main flow outlet; and a return air conduit coupled to the body, the return air conduit having a return air inlet and a return air outlet, the return air inlet disposed within the main passageway and facing the main flow inlet;
wherein the dryer exhaust coupling is configured to be removably coupled to a dryer exhaust outlet of a clothes dryer such that the exhaust air discharged from the clothes dryer flows into the main flow inlet, and wherein the return air inlet is configured to receive a portion of the exhaust air discharged from the clothes dryer and discharge that portion through the return air outlet and a remainder of the exhaust air being discharged through the main flow outlet.

2. The heat recovery device of claim 1, wherein when the heat recovery device is coupled to the dryer exhaust outlet, the central axis is substantially horizontal.

3. The heat recovery device of claim 2, wherein the return air outlet is configured to discharge the portion of the exhaust air from the clothes dryer in a direction substantially perpendicular to the central axis.

4. The heat recovery device of claim 1, wherein the return air inlet has a cross-section that is one of circular, semi-circular, elliptical, rectangular, square, or triangular.

5. The heat recovery device of claim 1 wherein the return air inlet is disposed in an upper half of the main passageway.

6. The heat recovery device of claim 1, wherein the return air conduit includes a cover with openings, the cover coupled to the return air outlet.

7. The heat recovery device of claim 6, wherein the cover is slideably removable from the return air outlet and the openings are elongated slots.

8. The heat recovery device of claim 6, wherein the return air conduit includes openings on at least one side of the return air conduit.

9. A heat recovery device for use on a clothes dryer, comprising:
a body having a main passageway with a central axis, the body having a first end and a second end and a dryer exhaust coupling proximate to the first end, the first end having a main flow inlet and the second end having a main flow outlet; and a return air conduit integrally formed to the body, the return air conduit having a return air inlet and a return air outlet, the return air inlet disposed within the main passageway and facing the main flow inlet, the return air outlet disposed outside the main passageway;

wherein the body and the return air conduit are comprised of a first half and a second half separable from each other along a plane extending through the central axis, wherein the dryer exhaust coupling is configured to be removably coupled to a dryer exhaust outlet of a clothes dryer such that the exhaust air discharged from the clothes dryer flows into the main flow inlet, and wherein the return air inlet is configured to receive a portion of the exhaust air discharged from the clothes dryer and discharge that portion through the return air outlet and a remainder of the exhaust air being discharged through the main flow outlet.

10. The heat recovery device of claim 9, further comprising one connector affixed to the body and one connector affixed to the return air conduit, each connector configured to couple together the first half and the second half.

11. The heat recovery device of claim 9, wherein a portion of the return air conduit external to the body has a T-shaped profile.

12. The heat recovery device of claim 9, wherein the return air conduit includes a cover with openings, the cover coupled to the return air outlet.

13. The heat recovery device of claim 12, wherein the cover is slideably removable from the return air outlet and the openings are elongated slots.

14. The heat recovery device of claim 12, wherein the return air conduit includes openings on at least one side of the return air conduit.

15. The heat recovery device of claim 9, wherein the dryer exhaust coupling is formed from a plurality of flexible tabs configured to be removably coupled to the dryer exhaust outlet of the clothes dryer.

16. The heat recovery device of claim 9, wherein the return air inlet has a semi-circular cross-section and the return air inlet is disposed in an upper half of the main passageway.

17. The heat recovery device of claim 9, wherein when the heat recovery device is coupled to the dryer exhaust outlet, the central axis is substantially horizontal.

18. The heat recovery device of claim 17, wherein the return air outlet is configured to discharge the portion of the exhaust air from the clothes dryer in a direction substantially perpendicular to the central axis.