FLAT SOLAR CHIMNEY FOR PASSIVE REDUCTION OF BUILDING COOLING LOADS

Abstract

A flat solar chimney in accordance with the invention reduces a building's cooling load by dissipating the solar energy outside the building. What Applicants have done is construct an outer wall having an inner air space before the building structure. The solar light is absorbed by the outside layer which includes a porous metal layer. The heated high surface area foam metal creates a convective air flow in the channel that extends vertically with openings at the bottom and top. This flow dissipates the absorbed heat and is totally external to the building's interior.

In a further embodiment of the invention, a plurality of rectangular slats either horizontally or vertically disposed act as venetian style blinds. The dynamic blinds allow visual function or the solar chimney as per need.

Claims

1. A flat solar chimney for reducing a building's cooling load during periods of excessive heat, said solar chimney comprising: an outer sun-facing wall of a building and an outer transparent wall having an inner surface outwardly spaced from the sun-facing wall of the building, and an opaque porous layer fixed to said inner surface of said outer transparent wall and spaced from said outer sun-facing wall of said building to thereby form an upwardly extending channel for convection of heated air; and an opening for said channel at a lower portion of said building and a second opening at an upper portion for heated air to flow by convection from the lower portion to the upper portion and exits said channel at said upper portion of said building without entering an inner space of said building.

2. A flat solar chimney for reducing a building's cooling load according to claim 1, which includes a plurality of heat transmitting fin like elements extending outwardly from said porous metal absorber for transmitting heat into said channel.

3. A flat solar chimney for reducing a building's cooling load according to claim 2, which includes an anti-reflective coating on said outer surface of said transparent wall.

4. A flat solar chimney for reducing a building's cooling load according to claim 2, in which said sun-facing building wall includes a layer of thermal insulation on an outer surface thereof.

5. A flat solar chimney for reducing a building's cooling load according to claim 4, in which said transparent or translucent wall includes an outer coating of low emissivity paint thereon.

6. A flat solar chimney for reducing a building's cooling load according to claim 2, which includes a glass transparent wall and a porous metal wall and an aerogel layer between said glass wall and said porous metal wall.

7. A flat solar chimney for reducing a building's cooling load according to claim 2, which includes a plurality of heat conducting fins extending into said channel from said porous metal layer.

8. A flat solar chimney for reducing a building's cooling load according to claim 2, which includes a plurality of horizontally disposed rectangular parallel blinds.

9. A flat solar chimney for reducing a building's cooling load according to claim 2, which includes a plurality of vertically disposed parallel rotatable parallel rectangular blinds.

10. A flat solar chimney for reducing a building's cooling load according to claim 8, in which said blinds are rotatable about a series of parallel axis (is that horizontal or vertical) fixed to an edge of each of said blinds.

11. A flat solar chimney for reducing a building's cooling load according to claim 8, in which each of said blinds is rotatable about one of a plurality of axis extending through a center of each of said blinds.

12. A flat solar chimney for reducing a building's cooling load according to claim 9, in which each of said blinds are rotatable about an edge of said blinds.

13. A flat solar chimney for reducing a building's cooling load according to claim 9, in which each of said blinds is rotatable about a vertical axis and blinds can be open as per user preference to see through from inside of the building to the outside.

14. A flat solar chimney for reducing a building's cooling load according to claim 9, in which a fan at the top portion of said channel of the upwardly extending channel induces forced convection of air.

15. A flat solar chimney for reducing a building's cooling load according to claim 2, in which said sun-facing wall of said building is sealed from the bottom to the top of said building to prevent heated air in said chamber from entering into the interior of said building.

16. A flat solar chimney for reducing a building's heating load in which said outer sun-facing wall of said building includes a first opening into said building from said upwardly extending channel and a second opening in an upper or top portion of said building to channel heat from said upwardly extending channel into the interior of said building.

17. The outward layer in claim 1 can also be opaque metallic, stone or concrete layer and has large surface area of metals that can be porous metal or fins toward the building side.

18. A flat solar chimney for reducing a building's cooling load according to claim 17, in which the material of claim 17 is a porous metal foam.

19. A flat solar chimney for reducing a building's cooling load according to claim 17, in which the material of claim 17 is a porous cement.

20. A flat solar chimney for reducing a building's cooling load according to claim 17, in which the material of claim 17 is a porous stone.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG. 1 is a side view of a solar chimney in accordance with a first embodiment of the invention;

[0017] FIG. 1A is a front view looking at or through a spaced apart transparent or translucent glass wall of a building that faces the winter sun;

[0018] FIG. 1B is a is a side view illustrating the positioning of the glass transparent wall with respect to the two triangular supports and one ground support together with the foundation of the south facing wall of the building;

[0019] FIG. 1C is a perspective view of a triangular support for positioning the transparent wall with respect to a south facing outer wall of the building;

[0020] FIG. 1D is a perspective view of a positioning support for supporting the separate glass wall positioned with respect to the south facing outer wall of the building;

[0021] FIG. 2 is a schematic side view of a plurality of heat conducting fins extending into an upwardly extending channel of a solar chimney in accordance with the invention;

[0022] FIG. 3 is a cross sectional view of a transmitting wall of a flat solar chimney for reducing a building's cooling load by deflecting solar energy away from a building as opposed to the inside of the building;

[0023] FIG. 4 is a further embodiment of the invention illustrating a plurality of heat transferring fins extending into an upwardly extending channel;

[0024] FIG. 5 illustrates an additional embodiment of the invention wherein an enclosed venetian style blind assembly includes a plurality of rotatable louvers or slats for directing the solar energy into an upwardly extending channel or the like;

[0025] FIG. 6 is a further illustration of FIG. 5 showing the blinds or louvers in an open position;

[0026] FIG. 7 is a top or plan view looking down on the louvers in the enclosed portion of a solar chimney;

[0027] FIGS. 8 and 9 illustrate a solar chimney as shown in FIGS. 6 and 7 and including enclosed blinds or louvers that are pivotal about an axis through the center of each of said louvers or blinds;

[0028] FIG. 10 is a top or plan view of a blind as shown FIGS. 8 and 9 in which the blinds are in an open position;

[0029] FIG. 11 is a side view of the rotatable blinds or louvers rotatable about axes extending through the midsection of each blind;

[0030] FIG. 12 is a further illustration of the blinds in FIG. 11 but a side view of the blinds in an open position;

[0031] FIG. 13 is a top or plan view looking down on an open blind that is rotatable about its axis running through its midsection;

[0032] FIG. 14 illustrates a solar chimney in accordance with a further embodiment of the invention and which includes an electric generator illustrated schematically as a fan at the top of the upwardly extending channel; and

[0033] FIG. 15 illustrates a further solar chimney wherein the invention is used for heating an interior of a building.

[0034] The invention will now be described in connection with the accompanying drawings wherein like reference numbers are used to identify like parts.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

[0035] In a first embodiment of the invention, a flat solar chimney for reducing the cooling load on a building during periods of excessive heat includes a flat solar chimney as shown in FIG. 1. As illustrated, a building 10 includes an outer wall 12 that is preferably facing the sun and a transparent or translucent separate glass wall 14 that is spaced apart from the sun-facing wall 12 of the building by 10 to 20 centimeters and forms an upwardly extending channel 16 between the sun-facing building wall 12 and the separate transparent wall 14. The channel 16 directs heated air upwardly from a lower point of the building 10 to the top 13 of the building 10.

[0036] As illustrated in FIG. 1A a transparent wall 14 is supported in front of a sun-facing building wall 12 and supported by a pair of ground based supports 120 with a support on each side of the south facing wall. As illustrated, the transparent wall 14 and sun-facing wall 12 of the building form an upwardly extending channel 16 with openings at the bottom and the top of the transparent wall 14. As illustrated, the upwardly extending channel extends from the bottom to the top of the building with a channel defined in between the transparent wall and the south facing building wall extending upwardly to direct a flow of air due to convection.

[0037] FIG. 1B is a schematic side illustration of the upwardly extending channel between the transparent wall and the south facing building wall with a pair of triangular supports spacing the transparent wall 14 from the south facing building wall. As shown, a ground support 123 and two triangular supports 125 space the wall away from the south facing building wall. Further detail of a triangular support is shown in FIG. 1C.

[0038] In FIG. 1D a ground support 120 positions the wall together with the triangular supports 125 in FIG. 1D. As illustrated in FIG. 1D, a metal support rest on or extends into a ground level foundation. The bottom of the wall extends into a cut out in the top of the support 120.

[0039] In FIG. 1 the dynamic process is described. The upwardly extending channel 16 has an opening at the bottom of the building 10 or at the bottom thereof and a second opening at the top of the building 10 which is sealed to prevent heated air from entering the building from the channel 16. The transparent or translucent wall 14 includes an outer glass support 15 and a porous metal absorber 18 in contact with the glass support 15 and plus an array of outwardly extending heat transmitting fins 19 or elements that extend outwardly into the channel 16.

[0040] The porous metal absorber 18 is immediately in back of and behind and/or in contact with the rear surface of the glass wall 14 and may include a conventional array 19 of metal fins extending rearwardly from the porous metal absorber 18 and extending rearwardly from a layer 20 of black paint on the rear surface of the absorber 19 and into the upwardly extending channel 16.

[0041] The outwardly extending fins are shown schematically as a series of short stubs 21 in FIG. 2 but in reality are flat fins similar to those in a core of an automotive radiator that extends into the channel 16.

[0042] As shown in FIG. 3, the transparent or translucent wall includes a glass support member 14 with an anti-reflective coating on a front surface on the glass wall 14. The glass wall 14 may also include a translucent aerogel layer 17 on the back of the transparent member 14. An aerogel layer would allow the solar radiation to pass through the outer transparent glass wall into the air channel and prevent it from reflecting back out the glass wall to the ambient. In other words, it works to trap the heat in the vertical air channel.

[0043] The aerogel layer is followed by a layer of foam metal absorbers 18 with a coating of black paint 19 on a rear surface thereof and finally an array 22 of thin metal sheet material 21 that is similar in thickness to the metal in an automotive radiator. Aerogel increases the temperature of the metal foam which eventually improve the natural convection.

[0044] As illustrated in FIG. 1, the building's sun-facing outer wall 12 is preferably sealed to prevent heat from the upper extending channel 16 from passage into the inner structure of the building 10. As illustrated in FIG. 3, the sun-facing outer wall 12 of the building 10 may preferably include a layer 17 of insulation to help protect the outer wall of the building from permitting heat produced by the sun's rays and a low emissivity coating on top of the layer 17. Layer 17 is not a thermal insulation but it is a low emissivity coating to reduce radiative heat transfer to the building or wall 12.

[0045] Further embodiments of the invention are shown in FIGS. 5-17 wherein a separate wall is outwardly moved away from the sun-facing wall 24 of the building 10 by about 10 to 20 centimeters and includes a pair of parallel walls 21 and 23 comprising a plurality of rotatable rectangular slats disposed in an enclosed box like chamber.

[0046] As shown, each of the chambers include a plurality of rotatable rectangular wooden, metal or plastic blades that are rotatable about parallel axes that may be horizontally or vertically disposed to rotate about the leading or trailing or midsection of each blind. The blinds which are basically rectangular shaped are rotatable about a leading edge, trailing edge or the midsection of each blind.

[0047] For example, FIGS. 1-10 illustrate blinds that are rotatable about a leading or trailing edge while FIGS. 5-13 illustrate the case where the blinds are rotatable about the central axis. It should also be recognized that the rotatable axes may be rotatable about a horizontal or vertical axes. Such axes may be disposed on the leading or trailing edges or the midsection of each of the blinds. For contrast, FIGS. 11-13 show blinds that are rotatable about the midsection of the blinds.

[0048] FIGS. 14 is a schematic illustration of a still further embodiment of the invention wherein a fan is shown at the exit of the upwardly extending channel near an exit near the top of the building for enhancing natural convection. Other electricity generating or other devices can be powered as desired.

[0049] While the invention has been illustrated for cooling a building during periods of elevated temperatures it should be recognized that the invention may be used for other applications without departing from the scope of the claims.

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