HK1133050A - Skylight tube with infrared heat transfer - Google Patents

Description

Skylight body with infrared heat transfer device

Technical Field

The present invention relates generally to skylights.

Background

Tubular skylights are disclosed in U.S. patent nos. 5,896,713 and 6,035,593, both of which are of the same assignee as the present invention and both of which are incorporated herein by reference. Both types of skylights can use the skylight dome disclosed in U.S. patent No. 5,896,712, also assigned to the same assignee as the present invention and incorporated herein by reference. These inventions represent the leading edge of the art, and one or more of them have been commercially successful.

Briefly, a tubular skylight such as that described above includes a tube assembly mounted between a roof and a ceiling of a building. The top end of the tube assembly is covered by a dome or cover mounted on the roof, such as the cover disclosed in the above-mentioned' 712 patent, while the bottom end of the tube assembly is covered by a ceiling mounted diffuser plate. With this combination, natural light from outside the building enters the interior of the building directly through the tube assembly for interior illumination.

Tubular skylights use reflective surfaces to transmit light down the tube from the roof to the interior ceiling. The spectral response of the dome, tube and diffuser, and the number of reflections that occur as light passes down the tube, determine how much light reaches the interior of the building. In addition to visible light, these properties also determine how much heat energy will be conducted to the interior of the building.

It is recognized herein that it is desirable to maximize the amount of visible light (light wavelengths of approximately 400nm-760nm) passing down the tube, while minimizing the amount of heat (in the form of infrared light having wavelengths greater than 760nm) passing into the room. It is further believed that many fenestration products designed to reduce the absorption of solar heat have drawbacks. For example, it is typically undesirable to stain the surface of a window with a coating or film, i.e., the stain reduces the transfer of heat, but also reduces the transfer of visible light. The same is true, only to a lesser extent, for low-e coatings and/or films deposited on window panes, as well as for multiple glazing units. Further, the same observation is made for skylights in which a film or coating is used to increase the visible light transmitted down the tube, while also increasing the heat input into the room, and in which the light blocking means of the dome or diffuser block visible light while blocking infrared light. Thus, a current solution is provided.

Disclosure of Invention

The skylight assembly includes a transparent dome and a skylight shaft substrate extending away from the dome, light entering the dome being transmitted through the shaft substrate. A spectrally selective film or coating is juxtaposed to the interior surface of the hoistway substrate to substantially reflect visible light and to substantially transmit infrared light.

If desired, means may be provided in combination with the substrate to conduct thermal energy from the inner surface to the outer surface of the substrate. The means for conducting heat may comprise a binder having particles of carbon black or other infrared absorbing substance disposed between the spectrally selective film and the substrate and/or it may comprise a bright black (satin black) on the inner surface of the substrate and an anodized outer surface of the substrate. Alternatively, the substrate has an outer surface with a relatively low ir emissivity and the inner surface or film has a high emissivity, with heat energy radiating within the tube and rising up and passing through the dome to the outside. Further, the substrate may be transparent so that infrared light is transmitted through the substrate while the film or coating keeps visible light inside the tube.

In another aspect, the skylight shaft assembly substrate has a hollow shaft substrate defining an interior surface and an exterior surface. An entity is bonded to the inner surface. The body substantially reflects visible light incident on the body and substantially does not reflect infrared light incident on the body.

In another aspect, the skylight shaft assembly substrate includes a hollow shaft substrate defining an interior surface and an exterior surface, and means associated with the interior surface for substantially reflecting visible light but not infrared light.

The details of the present invention, both as to its structure and operation, can best be understood in reference to the accompanying drawings, in which like reference numerals refer to like parts, and in which:

drawings

FIG. 1 is a partial cross-sectional side view of a tubular skylight of the present invention;

FIG. 2 is a perspective view of a tube having a spectrally selective film or coating in accordance with the present invention;

FIG. 3 is a cross-sectional view taken along line 3-3 of FIG. 2;

FIG. 4 is a cross-sectional view of an alternative embodiment as seen along line 3-3 of FIG. 2;

FIG. 5 is a cross-sectional view of the alternate embodiment as taken along line 3-3 of FIG. 2;

FIG. 6 is a partial cross-sectional side view of an alternative embodiment of a tubular skylight of the present invention;

FIG. 7 is a partial cross-sectional side view of another alternative embodiment of a tubular skylight of the present invention;

FIGS. 8 and 9 are cross-sectional views of the respective embodiments as viewed along circle 8-8 of FIG. 7;

FIG. 10 is a partial cross-sectional side view of another alternative embodiment of a tubular skylight of the present invention;

fig. 11 is a cross-sectional view of the hoistway floor of fig. 10.

Detailed Description

Referring first to FIG. 1, a tubular skylight made in accordance with the present invention, generally designated 10, is provided for illuminating an interior room 12, generally designated 16, located within a building having a ceiling mounted wall 14 within the room 12. In fig. 1, a building 16 has a roof 18 and one or more joists 20, the joists 20 supporting the roof 18 and ceiling 14.

As shown in FIG. 1, the skylight 10 includes a rigid hard plastic or glass roof-mounted covering 21, the covering 21 being light-transmissive, preferably transparent. In one embodiment, the cover 21 may be the cover disclosed in the above-mentioned' 712 patent. Alternatively, the cover 21 may be other suitable covers, such as the covers sold commercially by the present assignee under the trade name "Solatube".

The cover 21 may be mounted to the roof 18 by a metal flashing 22 similar to a ring, the flashing 22 being connected to the roof 18 in a manner known in the art. The metal flashing 22 is angled to fit the slope of the roof 18 to engage and support the covering 21 in a generally vertical upright orientation as shown.

As further shown in fig. 1, an internally reflective hollow shaft assembly, generally designated 24, is attached to the flashing 22. The assembly 24 may be circular, rectangular, triangular, etc. in cross-section. Thus, while the term "tube" is sometimes used herein, it is to be understood that the principles of the present invention are not limited to a cylindrical shape per se unless otherwise specified.

The shaft assembly 24 extends to the ceiling 14 of the interior room 12. In accordance with the present invention, the shaft assembly 24 directs light entering the shaft assembly 24 downwardly to a light diffusing assembly, generally indicated at 26, disposed within the room 12 and mounted to the ceiling 14 or joists 20, as described in the aforementioned' 953 patent. In some instances for a "light well," the light diffusing component 26 is typically omitted.

The shaft assembly 24 may be made of metal, such as aluminum alloy or steel, or may be made of plastic or other suitable material as disclosed below. The interior of the shaft assembly 24 is treated in a manner as disclosed below.

It is recognized herein that existing multilayer polymeric reflective films can be configured to reflect or transmit light depending on the wavelength of the light. Such films can be considered to be spectrally selective. In particular, the present invention contemplates that the multilayer polymeric reflective film can be configured to reflect visible light, as indicated by line 30, while transmitting Infrared (IR) light to the tube substrate (in the example shown in FIG. 1, thermal energy is transmitted through the tube substrate to the exterior of the skylight, as indicated by line 32, but in other embodiments as described below, the thermal energy can travel up the tube substrate). A non-limiting example of such a Film is "Daylighting Film-DF2000 MA", manufactured by Minnesota Mining and Manufacturing (3M).

Thus, as shown in FIG. 2, a multilayer selectively conductive film or coating 40 that reflects visible wavelengths and transmits Infrared (IR) wavelengths may be adhered to a tube substrate 42, it being understood that the tube substrate 42 may be used with any of the tubes and/or tube segments described above. Light of visible wavelengths is reflected by the film 40, while light in the Infrared (IR) portion of the spectrum is transmitted through the film to the tube 42.

As shown in fig. 2, the multilayer film 40 is adhered to the inner surface 44 of the tube 42. Fig. 3 best shows that the film 40 (which may be a coating as shown) is adhered to the tube 42 using a clear adhesive 46. The tube 42 may be made of aluminum, and in particular, when a clear adhesive is used, the inner surface 44 may be painted with a bright black (satin) or otherwise treated for high heat absorption. Rather, the outer surface 48 of the substrate 42 is preferably anodized or coated or otherwise treated to impart a high thermal conductivity to allow heat energy to be transferred from the inner surface 44 to the outer surface 48. Thus, the outer surface 48 has a high emissivity (emittance) to radiate thermal energy outward from the pipe body, while the inner surface 44 may have high ir absorption and low ir reflectance characteristics.

Alternatively, as shown in FIG. 4, rather than treating the inner surface 44 to be absorptive, an opaque (infrared absorbing) adhesive 50 is disposed between the multilayer film or coating 40 and the tube substrate 42. The binder 50 may be a mixture of a transparent binder and carbon black or other infrared absorbing solid particles, and thus, the opaque binder has characteristics of high infrared absorptivity and low infrared reflectivity.

Alternatively, as shown in FIG. 5, a spectrally selective multilayer coating 52 that reflects visible light but transmits infrared light can be deposited directly onto an infrared-absorptive inner surface 54 of a substrate 56 without an adhesive, the substrate 56 having a high emissivity outer surface 58. The substrate 56 shown in fig. 5 is otherwise identical in all essential respects to that shown in fig. 3 and 4.

FIG. 6 shows an alternative skylight assembly 100 with a tube substrate 102 that is identical in all material respects to the assembly 10 shown in FIG. 1, with the following exceptions. In order to conduct infrared light away from the pipe body, an outer hollow shell 104 is provided which essentially completely surrounds the pipe base 102, with a space 106 between the shell 104 and the base 102, along which space the infrared radiation propagates upwards, as indicated by heat rays 108. Thermal energy is transmitted through the open top end of the shell 104 and, if the top end is closed, through an opening 110 formed in the flashing or other structure of the skylight assembly 100. Alternatively, a transparent plastic dome 114 with a high emissivity (to infrared light) is used so that heat energy is conducted up through the dome to the exterior of the assembly 100.

FIGS. 7-9 illustrate another alternative embodiment of a skylight assembly 200 that is identical in all material respects to the assembly 10 shown in FIG. 1, with the following exceptions. In both examples shown in fig. 8 and 9, the outer surface 201 of the tube substrate 202 need not be highly emissive to infrared light. As in the case of the previous embodiments, the inner surface area is preferably infrared absorbing and visible light reflecting, so that the multilayer film 204 is bonded to the inner surface of the substrate 202 using an infrared absorbing adhesive 206 as shown in fig. 8, or the element 204 may be a multilayer coating deposited onto the substrate 202, in which case the element 206 itself may be the inner surface treated to be more absorptive, e.g., coated with carbon black or other infrared absorbing entity. The latter example is shown in greater detail in fig. 9.

In summary, returning to FIG. 7, due to the low emissivity of the outer surface 201, most of the thermal energy absorbed by the substrate 202 propagates through the opening or aperture 210 and over the assembly 200, the opening or aperture 210 being formed in the skylight dome 212, or between the dome 212 and the flashing 214 to which the dome 212 is mounted. Alternatively, no apertures need be provided, in which case the dome 212 is preferably highly emissive to infrared light, so that thermal energy can propagate up through the dome and out of the skylight assembly 200.

FIGS. 10 and 11 illustrate another alternative embodiment of a skylight assembly 300 that is identical in all material respects to the assembly 10 shown in FIG. 1, with the following exceptions. The assembly 300 shown in fig. 10 and 11 has a transparent plastic substrate 302, the inner surface of which transparent plastic substrate 302 is covered with a multilayer film or coating 304, the multilayer film or coating 304 being spectrally selective, i.e., reflecting visible light and transmitting infrared light. If desired, the multilayer film or coating 304 can be adhered to the substrate by a clear adhesive 306. With this combined structure, visible light is reflected downward within the tube, as shown by line 308 in FIG. 10, while infrared light is transmitted through the tube to the exterior, as shown by line 310.

Although a particular skylight tube having an infrared heat transfer assembly is illustrated and described in detail herein, the invention is not limited except as by the appended claims.

Claims (10)

1. A skylight assembly, comprising:

a transparent dome (21, 114, 212);

at least one skylight shaft substrate (42, 102, 202, 302) extending away from said dome (21, 114, 212), light entering the dome (21, 114, 212) being transmitted through said shaft substrate (42);

a spectrally selective film or coating (40, 52, 204, 304) juxtaposed to an interior surface of the hoistway floor (42, 102, 202) to substantially reflect visible light and to substantially transmit infrared light.

2. The assembly of claim 1, further comprising means associated with said substrate (42, 102, 202, 302) for transferring thermal energy from an interior surface to an exterior surface of said substrate (42, 102, 202, 302).

3. The assembly of claim 2, wherein the means for transferring thermal energy comprises an adhesive (50, 206) disposed between the spectrally selective film (52, 204) and the substrate (42, 202) and having carbon black and/or other infrared absorbing substance particles.

4. The assembly of claim 2 wherein the means for transferring thermal energy comprises a bright black and/or other infrared absorptive inner surface (44) of the substrate (42, 102, 202).

5. The assembly of claim 4 wherein the means for transferring thermal energy comprises an anodized or other high emissivity outer surface (48) of the substrate (42, 102).

6. The assembly of claim 2, wherein the means for transferring thermal energy comprises a spectrally selective coating (52, 204, 304) deposited onto the substrate (42).

7. The assembly of claim 1, wherein the substrate (202) has an outer surface (201), the outer surface (201) has a relatively low emissivity to infrared, and thermal energy propagates upwardly through the substrate (202) and the inside of the pipe body.

8. The assembly of claim 1, wherein the skylight shaft substrate (302) is transparent.

9. A skylight shaft assembly, comprising:

a hollow riser substrate (42, 102, 202, 302), the hollow riser substrate (42, 102, 202, 302) defining an interior surface and an exterior surface;

a body (40, 52, 204, 304) associated with the inner surface, the body (40, 52, 204, 304) substantially reflecting visible light incident on the body and substantially not reflecting infrared light incident on the body.

10. The assembly of claim 9, further comprising an adhesive (50, 206) disposed between the body and the substrate (42) and having carbon black and/or other infrared absorbing substance particles.