Method and apparatus for preheating ventilation air for a building

Abstract

A solar air heating system for a building having a vertical, south-facing wall. The system has a perforated panel covering the wall. Vertical frame members fasten the panel to the wall to space the panel a short distance away from the wall and to form an air channel between the wall and panel. There is an air collecting space at the bottom of the channel, adjacent the wall. An air inlet in the wall connects the air collecting space to the interior of the building. A fan in the inlet draws outside air into the channel through the perforations in the panel, from the channel into the air collecting space, and from the air collecting space into the building through the air inlet.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority of Canadian application no. 2,559,641, filed 13 Sep. 2006, and which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention is directed toward a solar air heating system for buildings.

2. Description of the Related Art

Solar air heating systems for buildings are known. The systems are used to heat ventilating air added to buildings. These known systems comprise a perforated, heat-absorbing panel mounted over at least a portion of the outside of a south-facing wall of a building, the panel spaced a short distance from the wall to form a vertical air channel between the panel and the wall. The sun heats the panel and air adjacent the outer surface of the panel. As the panel heats, it further heats the air adjacent the outer surface of the panel. The heated air rises along the panel outer surface and passes into the air channel through perforations in the panel. The panel also heats the air in the channel causing the air in the channel to rise to the top of the building from where the air is collected in a collector duct and directed therefrom through an inlet into the building. A fan is employed in the collector duct or inlet to help draw the heated air on the outer surface of the panel into the channel through the perforations, and to draw the air in the channel upwardly and into the building.

These known systems have disadvantages however. The top of the system gets very hot and as a result there is considerable heat loss to the outside air making the system inefficient. Attachment of the system to the top of the building is difficult since the collecting duct at the top of the system is in the way.

This makes it difficult to attach the panel and its support members to the top framing part of the building. Servicing and maintenance of the fan in the collector duct or inlet is difficult because of its high location. The perforations in the panel are designed to facilitate upward flow of air into the channel. The configuration of the openings limits the design variations available in the make-up of the panel.

SUMMARY OF THE INVENTION

It is the purpose of the present invention to provide a solar air heating system that is simpler in construction, simpler and easier to install, more efficient in use, easier to service, and lends itself to a greater variety in design of the panel.

In accordance with the present invention a solar air heating system is provided having a perforated, heat-absorbing panel mounted over at least a portion of the outside of a south wall of a building, the panel spaced a short distance from the wall to form a vertical air channel. An air inlet is provided in the bottom half of the building wall, preferably near the bottom of the wall. A fan is located in the inlet to draw air from outside the panel into the channel through perforations in the panel and from the channel through the air inlet into the building. The sun heats the panel and outside air adjacent the panel. The operation of the fan moves air in the channel toward the inlet and into the building and draws the heated air on the outer surface of the panel into the channel through the perforations in the panel. The air in the channel is heated by the sun-warmed panel, by the sun-warmed air entering the channel through the perforations, and by any heat coming through the wall from inside the building.

The panel can be mounted to the building wall with vertical, horizontal or a combination of vertical and horizontal frame members depending on the construction of the panel. The frame members are fastened on one side to the building wall and the panel is fastened to the other side of the frame members. To facilitate air flow within the channel toward the air inlet in the building wall, the frame members are preferably perforated. The perforations in the frame members not only facilitate air flow in the channel both vertically and horizontally but also reduce the weight of the frame members making installation easier.

The system could be provided with a horizontal air collector duct at the bottom of the panel to collect the air from the air channel, the duct leading to the air inlet in the bottom of the building wall. While satisfactory, the use of a bottom horizontal collector duct can lead to a pressure drop in the air flow due to the abrupt change of direction of the air flow. In place of an air collecting duct, a bottom portion of the panel can be angled outwardly away from the building wall at the bottom to form an air collecting space at the bottom of the channel thus simplifying the construction. The air inlet in the building wall is centered within the air collecting space between its sides. The air collecting space, continually enlarging toward the bottom of the system, allows the air to expand on emerging into the collecting space from the channel increasing air flow in the channel. In addition, the angled panel portion faces the sun at a better heating angle improving air heating efficiency in the area of the collecting space.

In an alternative construction, the entire panel can be angled slightly outwardly to make the channel wider at the bottom than at the top. The air inlet to the building is at the bottom of the tapered channel. The air flow through the channel is improved since the channel continually enlarges moving toward the bottom. The angled panel also faces the sun at a slightly better heating angle than a vertical panel improving heating efficiency of the air.

Having the inlet located in the lower half of the wall of the building, and preferably near the bottom of the building wall, provides several advantages. With the air flowing generally downwardly in the vertical channel, the temperature profile in the channel is more uniform over its height, the heat loss from the channel is reduced since there are no hot areas in the channel, and the system is more efficient. In addition, having the air inlet into the building low down makes installation and servicing of the fan in the inlet much simpler and easier. If an air collector duct is employed, it also is located low down adjacent the inlet and this location makes it easier to attach the panel and the panel frame members, particularly their top portions, directly to the framing of the building.

Also in accordance with the present invention, the perforations in the panel are made circular. The panel can be made from siding members, which can be mounted in various positions on the building wall to provide design variations improving the appearance of the building. The circular perforations allow mounting of the siding members in various positions without adversely affecting the flow of air through the perforations into the channel.

The invention is particularly directed toward a solar air heating system for a building having a vertical, south facing wall, the system having a perforated, heat-absorbing, panel for covering the wall, the bottom of the panel at the bottom of the wall. Frame members fasten the panel to the wall to space the panel a short distance away from the wall to form an air channel between the wall and the panel. There is an air inlet from the channel to the interior of the building, the inlet in the building wall below the mid-height of the panel. There is a fan in the inlet, drawing outside air into the channel through the perforations and from the channel through the inlet into the building. Preferably the frame members are also perforated allowing air flow through the channel in all directions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-section view of the solar air heating system;

FIG. 2 is a detailed cross-section view taken along line 2-2 in FIG. 1;

FIG. 3 is a detailed elevation view of heating system;

FIG. 4 is a cross-section view of another embodiment of the heating system;

FIG. 5 is a cross-section view of a further embodiment of the heating system;

FIG. 6 is a cross-section view of another embodiment of the heating system;

FIG. 7 is a another cross-section view of another embodiment of the heating system; and

FIG. 8 is a cross-section view taken along line 8-8 in FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The solar air heating system, as shown in FIGS. 1-3, has a perforated, heat-absorbing panel 1 mounted on a south facing wall 3 of a building 5. The panel could be coated on its outside surface with a black paint to make it heat absorbing. The panel 1 is spaced a short distance from the wall 5 to form an air channel 7. The panel 1 can be made up of a plurality interlocked siding members 9, the siding members mounted horizontally on the building 5. The siding members 9 have circular perforations 11 therein, the perforations 11 normally equally spaced apart. The perforations 11 are about 0.0625 inches in diameter and there are about 3 to 8 perforations per square inch of panel but the size and density of perforations can vary depending on the amount of air required to be added to the building for heating or ventilation purposes.

To mount the siding members 9 horizontally to form the panel 1, a plurality of vertical frame members 15, horizontally spaced apart, are used to connect the members 9 to the wall 5. The frame members 15 can be in the form of zee channels. One inner arm 17 of each frame member 15 is fastened to the wall 5 by suitable fastening means and the siding members 9 are then fastened to the other outer arms 19 of the frame members by suitable fastening means. The vertical frame members 9 are about as long as the panel 1 and help direct the air vertically through the air channel 7. The sides of the panel 1 can be fastened to the wall 5 by frame members (not shown) having a u-shaped cross-section to close the sides of the air channel 7. The frame members can have profile shapes other than a zee shape.

A horizontal air collector duct 23 is provided at the bottom of the panel 1. The duct 23 is slightly wider than the channel 7 and the channel 7 leads into the duct 23. An air inlet 25, generally centrally located in the duct 23, leads from the duct 23 through the building wall 3 into the building 5. A fan 27 is located in the inlet 25. The top of the channel 7 is closed by a top wall 29. The frame members 9 are shown only in the air channel 7 but they could extend into the collector duct 23.

In operation, the sun heats the panel 1 and the sun and the panel 1 heat the air adjacent the outside surface 30 of the panel. The heated air begins to flow up along the panel until it encounters a circular perforation 11 and is then pulled into the channel 7 by the fan 27 and down to the collector duct 23. As the air flows down the channel 7 to the duct 23 it is further heated by the sun-warmed panel 1 and by any heat escaping from the building through the wall 3. The air expands slightly moving into the collector duct 23, facilitating flow through the channel 7, and is then drawn into the building from the duct through the inlet 25.

It will be seen that the temperature profile of the air in the channel is more uniform with no hot spot, particularly at the top of the channel as in the prior art, where heat can be lost from the channel to the outside, as air leaves the channel. The air coming into the channel near the bottom is relatively cool in comparison to the air in the channel moving down the channel and thus the air in the channel is not overheated. Also any heat from the building comes into the channel hotter near the top than at the bottom thus not overheating the air where it leaves the channel.

The upper part of the panel 1 and the panel frame members 15 are easily attached to the top of the framing of the building since the collector duct is located at the bottom of the system out of the way. The weight of the panel and the frame members is readily supported from the top of the building framing and need only be attached to the bottom of the building in a non-weight bearing manner making installation easier. The fan installation and servicing is easier at ground level.

The system described can be modified by eliminating the collector duct 23 and instead having a short, bottom portion 31 of the panel 1′ angled outwardly as shown in FIG. 4. The bottom portion 31 is angled outwardly from the long, top portion 33 of the panel 1′ about a horizontal bend line 35. The angling of the bottom portion 31 of the panel 1′ forms, with wall 3′, an enlarged, elongated air collector space 37 at the bottom of the air channel 7′ for the heated air being drawn downwardly. The collector space 37 is closed by a bottom wall 38. The space 37 enlarges toward the bottom thus improving the flow of air within and from the channel. In addition, the angled bottom portion 31 of the panel 1′ is better oriented with respect to the sun and thus more efficient in heating the air. The inlet opening 25′ is centrally located within the collector space 37 between its sides. The bottom portion 31 of the panel 1′ is perforated in the same manner as the top portion 33 of the panel. The vertical framing members 15′ are shown only in the air channel 7′ but they can extend to the bottom of the collector space 37. Special end frame members (not shown) are used to close the sides of the air channel 7′ and the sides of the collector space 37.

In another embodiment, the entire panel 1″ may be angled outwardly from its top edge 43 as shown in FIG. 5. In this embodiment, the vertical framing members 15″ would increase in width from the top toward the bottom to properly support the panel 1″ and would terminate a short distance up from the bottom above an air collecting space 37′. A major, top portion 45 of the panel 1″ forms, with the wall, the air channel 7″. A minor, bottom portion 46 of the panel forms, with the wall 3″, the collecting space 37′. The air collecting space 37′ tapers toward the channel 7″ which continues the taper toward the top. The bottom of the air collector space 37′ is closed by a bottom wall 38′. Tapered end frame members (not shown) would close the sides of the air channel 7″ and the collector space 37′. The inlet 25″ is centrally located in the collecting space 37′. The angling of the entire panel 1″ places it in a more efficient heating position relative to the sun and also improves the flow of the air downwardly through the channel 7″ toward the inlet 25″.

In a further embodiment, the webs 21, 21′, or 21″ of the vertical framing members 15, 15′ or 15″ could be perforated with perforations 47 to allow the air flowing in the channels 7, 7′, or 7″ to move laterally as well as vertically. The fan would pull the air coming down the channel laterally toward the vertical center of the system where the building inlet 25, 25′, or 25″ is located. The perforations 47 would also lighten the framing members making them easier to handle.

Perforated framing members permit a very simplified heating system to be used. As shown in FIG. 6, the simplified system can comprise a perforated panel 101 supported by perforated framing members 115 to form a channel 107. The inlet 125 can be located anywhere in the bottom half of the channel 107 since the fan 123 can pull the air both vertically and transversely through the channel 107 and the perforations 147 in the frame members 115.

No air collecting duct or air collecting space is needed in this embodiment, the channel itself acting as an air collecting space. The top, bottom and sides of the channel 107 are closed by top, bottom and side walls.

If desired a louver 149 can be provided in the panel 101 adjacent or near the inlet opening 125 to allow cooler outside air to flow into the channel 107 and to mix with the heated air to cool it in the summer if needed. A similar louver could be used in any of the panels 1, 1′, or 1″ in the other embodiments previously described.

The siding members 209 forming the panel 201 could be mounted vertically. In this variant, as shown in FIGS. 7 and 8, narrower vertical frame members 215 could be used along with horizontal frame members 210 in all the embodiments previously shown with horizontal siding members. The horizontal frame members 210 are attached to the outer arms 219 of the vertical frame members 215 as shown in FIGS. 7 and 8. The horizontal frame members 210 are vertically spaced-apart. The vertical siding members 209 are attached to the horizontal frame members 210, which can have a u-shaped cross-section, with suitable fastening members (not shown). Perforations 247 can be provided in the webs 221 of the vertical frame members 215 and perforations 248 can be provided in the webs 222 of the horizontal frame members 210. Top panel 231 can close the top of channel 207 and the duct 223 can close the bottom of the channel. Side panels close the sides of the channel 207. The vertical siding members 209 are straight in this embodiment and in the embodiment shown in FIG. 6; bent as shown in the embodiment in FIG. 4 or angled as shown in the embodiment in FIG. 5. If bent or angled, the vertical frame members could be shaped to fit the bent or angled configurations with the horizontal frame members being uniform. Alternatively, the vertical frame members could be uniform with the horizontal frame members progressively deepening toward the bottom, where needed, in the bent or angled configurations. The siding members could also be mounted diagonally.

While this invention has been described as having a preferred design, it is understood that it is capable of further modifications, and uses and/or adaptations of the invention and following in general the principle of the invention and including such departures from the present disclosure as come within the known or customary practice in the art to which the invention pertains, and as may be applied to the central features hereinbefore set forth, and fall within the scope of the invention or limits of the claims appended hereto.

Claims

1. A solar air heating system for a building having a vertical, south-facing wall, the system having a heat-absorbent panel for covering the wall; perforations in the panel allowing air to flow through the panel; vertical frame members for fastening the panel to the wall to space the panel a short distance away from the wall and to form an air channel between the wall and panel; an air collecting space at the bottom of the channel, adjacent the wall; an air inlet in the wall to connect the air collecting space to the interior of the building; and a fan in the inlet to draw outside air into the channel through the perforations in the panel, from the channel into the air collecting space, and from the air collecting space into the building through the air inlet.

2. A solar air heating system as claimed in claim 1 wherein the air collecting space is a collecting duct extending across the width of the panel, the duct slightly deeper than the channel.

3. A solar air heating system as claimed in claim 1 wherein the panel has a vertical top portion parallel to the wall to form, with the wall, the air channel and a bottom portion that is angled outwardly from the bottom of the top portion to form, with the wall, the air collector space.

4. A solar air heating system as claimed in claim 1 wherein the panel is angled slightly outwardly away from its top edge; a top, major, portion of the panel forming, with the wall, the channel; the channel being tapered from its bottom end to its top end; the bottom, minor portion of the panel forming, with the wall, the air collector space; the bottom end of the channel connected to the top of the air collector space; the air collector space tapered toward the channel.

5. A solar air heating system as claimed in claim 1 wherein the panel is made from horizontal siding members, the siding members fastened to the vertical frame members.

6. A solar air heating system as claimed in claim 2 wherein the panel is made from horizontal siding members, the siding members fastened to the vertical frame members.

7. A solar air heating system as claimed in claim 3 wherein the top portion of the panel is made from horizontal siding members, the siding members fastened to the vertical frame members.

8. A solar air heating system as claimed in claim 4 wherein the top portion of the panel is made from horizontal siding members, the siding members fastened to the vertical frame members.

9. A solar air heating system as claimed in claim 1 wherein the panel is made from vertical siding members, horizontal frame members attached to the outside of the vertical frame members, the vertical siding members attached to the horizontal frame members.

10. A solar air heating system as claimed in claim 2 wherein the panel is made from vertical siding members, horizontal frame members attached to the outside of the vertical frame members; the vertical siding members attached to the horizontal frame members.

11. A solar air heating system as claimed in claim 3 wherein the panel is made from vertical siding members, horizontal frame members attached to the outside of the vertical frame members, the vertical siding members attached to the horizontal frame members.

12. A solar air heating system as claimed in claim 4 wherein the panel is made from vertical siding members, horizontal frame members attached to the outside of the vertical frame members, the vertical siding members attached to the horizontal frame members.

13. A solar air heating system as claimed in claim 1 wherein the perforations are circular.

14. A solar air heating system as claimed in claim 2 wherein the perforations are circular.

15. A solar air heating system as claimed in claim 3 wherein the perforations are circular.

16. A solar air heating system as claimed in claim 4 wherein the perforations are circular.

17. A solar air heating system for a building having a vertical, south wall, the system having a heat-absorbing panel covering the wall, the bottom of the panel at the bottom of the wall; perforations in the panel allowing air to flow through the panel; vertical frame members for fastening the panel to the wall to space the panel a short distance away from the wall and to form an air channel between the wall and panel; perforations in the frame members; an air inlet in the lower portion of the wall to connect the channel to the interior of the building and a fan in the inlet to draw outside air into the channel through the perforations in the panel and then into the building, from the channel through the air inlet, the air passing through the perforations in the frame members in the channel.

18. A solar air heating system as claimed in claim 17 wherein the perforations in the panel are circular.

19. A solar air heating system as claimed in claim 17 wherein the panel is made from horizontal siding members, the siding members fastened to the vertical frame members.

20. A solar air heating system as claimed in claim 17 wherein the panel is made from vertical siding members, horizontal frame members attached to the outside of the vertical frame members, the vertical siding members attached to the horizontal frame members.

21. A solar air heating system as claimed in claim 18 wherein the panel is made from horizontal siding members, the siding members fastened to the vertical frame members.

22. A solar air heating system as claimed in claim 18 wherein the panel is made from vertical siding members, horizontal frame members attached to the outside of the vertical frame members; the vertical siding members attached to the horizontal frame members.

23. A solar air heating system as claimed in claim 17 including an air collector duct at the bottom of the channel between the panel and the building wall, the duct extending across the width of the panel, and being slightly deeper than the channel, the channel opening into the duct; and the air inlet located in the duct.

24. A solar air heating system as claimed in claim 17 wherein the panel has a vertical top portion parallel to the wall to form, with the wall, the air channel; the panel having a bottom portion that is angled outwardly from the bottom of the top portion to form, with the wall, the air collector space.

25. A solar air heating system as claimed in claim 17 wherein the panel is angled slightly outwardly away from its top edge; a top, major, portion of the panel forming, with the wall, the channel; the channel being tapered from its bottom end to its top end; the bottom, minor portion of the panel forming, with the wall, the air collector space; the bottom end of the channel connected to the top of the air collector space; the air collector space tapered toward the channel.