The present invention relates to photovoltaic (“PV”) roofing tiles. In particular, the present invention relates to a PV roofing tile with a fire suppression capability.
PV roofing tiles, also known as solar power roofing tiles, are well known in the art and are used in both commercial and residential roofs. However, unlike typical roofing tiles, PV roofing tiles are not or cannot be easily made flame retardant by conventional means. For example, conventional roofing tiles typically composed of polymeric or synthetic materials are made flame retardant by the addition of flame retardant additives such as aluminum tri-hydrate, magnesium hydroxide, halogenated fire retardants, and phosphorus flame retardants.
Such additives have various means by which they achieve fire retardation. In the case of aluminum tri-hydrate and magnesium hydroxide, the compounds decompose at elevated temperatures, absorbing energy and releasing water.
While conventional PV roofing tiles are made from glass, PV roofing tile manufacturers are now looking into PV tiles constructed in part with a flexible laminate and a polymeric cover film. The polymeric cover film must be weather resistant and is typically made from a fluoropolymer. While fluoropolymer films can be flame retardant, encapsulants, which are used in the PV roofing tiles, can burn and cannot be easily made flame retardant. As such, encapsulants, such as EVA, can adversely affect the flammability resistance of the PV roofing tile.
As such, there is a need to provide for a roofing tile and, in particular, a PV roofing tile, having fire suppression or flame retardant capabilities to further improve the safety of building materials.
Briefly stated, the present invention is directed to a photovoltaic roofing tile which includes a substrate having a first substrate surface, a second substrate surface, a first end, and a second end. The first substrate surface faces away from the second substrate surface. The first end is on an opposite side of the substrate from the second end. A photovoltaic laminate is positioned over the substrate. A fire suppression material is arranged proximate the first end of the substrate.
In another aspect, the present invention is directed to a roof assembly which includes a deck having a mounting surface. A plurality of photovoltaic roofing tiles are arranged on the deck in an overlapping relationship. Each photovoltaic roofing tiles includes a substrate having a first substrate surface, a second substrate surface, a first end, and a second end. The first substrate surface faces away from the second substrate surface. The first end is on an opposite side of the substrate from the second end. A photovoltaic laminate is positioned over the substrate. A fire suppression material is arranged proximate the first end of the substrate.
The foregoing summary, as well as the following detailed description of the invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there are shown in the drawings embodiments which are presently preferred. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown.
In the drawings:
Certain terminology is used in the following description for convenience only and is not limiting. The words “right”, “left”, “lower” and “upper” designate directions in the drawings to which reference is made. The words “inwardly” and “outwardly” refer to directions toward and away from, respectively, the geometric center of the roofing tile and designated parts thereof. Unless specifically set forth herein, the terms “a”, “an” and “the” are not limited to one element but instead should be read as meaning “at least one”. The terminology includes the words noted above, derivatives thereof and words of similar import.
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In the first embodiment the substrate 12 preferably includes a flange 14 extending from a first end 12c at an angle with respect to the first substrate surface 12a. The flange 14 preferably extends generally perpendicular with respect to a plane defined by the substrate 12 or with respect to the first substrate surface 12a, although other angular orientations are possible without departing from the spirit and scope of the invention. The flange 12 preferably extends from the first end 12c a distance to provide a mounting surface for a fire suppression material as described in more detail below.
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The PV laminate 18 preferably is substantially coextensive with the upper surface of the substrate 12 so as to maximize the electricity-producing area of the PV roofing tile 10. The PV laminate 18 may be arranged so as to not extend all the way to the peripheral portions of the substrate 12. Additionally, placing a PV laminate 18 in portions that will not be exposed to sunlight is inefficient and is preferably avoided. Accordingly, if the PV roofing tiles 10 are going to be arranged in a overlapping relationship (explained more fully below), any portions of the substrate 12 which will eventually be covered by a substrate 12 from another PV roofing tile 10 or non-PV roofing tile are preferably not covered with the PV laminate 18. The area of coverage and of no coverage by the PV laminate 18 is preferably predetermined depending on the intended use of the roofing tiles. It may be possible for the PV laminate 18 to extend to portions of a substrate 12 that will be covered by another substrate 12, except that such portions of the PV laminate 18 will preferably lack the PV cells 20 to reduce cost. Thus, merely extending the polymeric portions of the PV laminate 18 to areas with no sunlight is possible. Preferably, matching the PV laminate 18 to the area with actual sun exposure is preferred because of lower cost and a reduction of the use of potentially flammable materials, such as the polymeric layers of the PV laminate 18.
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The fire suppression member 28 may be on any portion of the substrate 12 that is suitable to protect the PV roofing tile 10 and/or underlying structures and/or other PV roofing tiles against fire. The fire suppression member 28 is preferably arranged on or proximate the first end 12c the substrate 12. For example, the fire suppression member 28 may be arranged on the flange 14, preferably the front surface of the flange 14 (this surface corresponds to the front surface 30 of the substrate 12 wherein the substrate comprises a flange 14). The front surface of the flange 14 is the surface which faces away from the substrate 12. The first end 12c of the substrate 12 has a predetermined length depending on the type of tile being used.
For instance, it may have one undulation or several. The fire suppression member 28 preferably extends substantially along the length of the first end 12c, as shown in
The fire suppression material is preferably an intumescent compound or material but it may comprise a fire agent and/or a flame retardant. The fire suppression material may be molded and comprise a fire suppression additive in combination with a binder where, preferably, the fire suppression additive is 50-90% by weight of the fire suppression material. The fire suppression member 28 may be coated and may comprise a layer comprising a fire suppression additive. The fire suppression additive layer may comprise an intumescent paint or paste, which is a paint or paste which comprises an intumescent additive. The fire suppression additive is preferably substantially comprised of the fire agent, flame retardant, and/or intumescent compound, and may be essentially completely comprised of the fire agent, flame retardant, and/or intumescent compound.
The binder which may be combined with a fire suppression additive can be a polymeric binder. Any polymeric binder readily known in the art and suitable for use as a binding material can be used. Such polymeric binders includes polyethylene, polypropylene, polyethylene waxes, latex binders, polyvinyl alcohol, natural rubber, polyurethane, calcium aluminate cement, combinations thereof, and the like.
The fire suppression member 28 can optionally comprise a colorant or can otherwise be colored to provide for an aesthetic look substantially the same as that of the substrate 12, PV laminate 18, and/or both. For example, the fire suppression member 28 may comprise pigments and/or dies as coloring. Pigments are preferred because of their increased tolerance to UV radiation. Moreover, a paint film, which comprises a paint layer with a protective clear coat, can be arranged over the fire suppression member 28 to provide a desired aesthetic look. The paint layer preferably comprises toner or resin with pigments. The protective clear coat can be a fluoropolymer such as ETFE or a urethane coating. The fire suppression member 28 and/or the paint film, preferably the protective clear coat, may comprise UV blockers such as titanium dioxide and/or stabilizers such as hindered amines to maintain appropriate coloring after long-term exposure to UV radiation.
When the fire suppression member 28 is formed with a fire agent, the fire suppression member 28 acts to suppress or fight a fire to which it is exposed. Such fire agents can include: foams; dry powders of sodium carbonate, sodium bicarbonate, calcium carbonate, calcium sulfate, calcium aluminum phosphate, silica; heat activated foams; heat activated blowing agents such as urea, butyl urea, dicyandiamide, benzene sulfonyl-hydrazide, melamine, guanidine, glycine; chemical foaming agents; azodicarbonamide; and combinations thereof, and the like. A molded fire suppression member 28 comprising a fire agent additive with a high concentration such as 50-90 weight % advantageously allows for a molded fire suppression member 28 to disintegrate and scatter upon being exposed to a sufficient fire hazard or temperature. Moreover, when the fire suppression member 28 is attached to the front surface 30 of the substrate 12, upon disintegration, the disintegrated fire suppression member 28 expands to form a fire wall preventing the fire from moving up or down the roof depending on the wind direction.
When the fire suppression member 28 is formed with a flame retardant, the fire suppression member 28 is made to improve fire resistant properties. Such flame retardants can include aluminum tri-hydrate, magnesium hydroxide, halogenated fire retardants, phosphorus flame retardants, organobromines, organochlorines, phosphorous, organophosphates, red phosphorous, antimony trioxide, boron compounds, borates, ammonium polyphosphate, combinations thereof, and the like. Preferably, when the fire suppression member 28 comprises a flame retardant, the fire suppression member 28 is arranged to cover as much front-facing surface 30 of the substrate 12 as possible. However, this coverage is also possible with fire suppression members 28 comprising a fire agent, flame retardant, and/or intumescent material.
When the fire suppression member 28 is formed with an intumescent compound or material, the fire suppression member 28 acts to form a fire stop by way of a char line formed by the intumescent compound or material. Intumescent compounds or materials per se are well known in the art and non-limiting exemplary intumescent compounds or materials include both hard and soft char producers and those that contain hydrates, sodium silicates, graphite, unexpanded vermiculite, unexpanded perlite, intumescent foam rubber, and/or combinations thereof, and the like.
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Additionally, the PV roofing tiles 10 can be in overlapping relationships with other PV roofing tiles 10 and/or with non-PV roofing tiles. For example, in order to improve the fire resistance of a roof assembly, a mixture of PV roofing tiles 10 and non-PV roofing tiles may be utilized. The PV roofing tiles 10 may outnumber the non-PV roofing tiles (or vice-versa) in a defined area of the roof or on the entire roof. Additionally, the PV roofing tiles 10 can be together in clusters with other PV roofing tiles 10 where the clusters are separated by non-PV roofing tiles 10. Alternatively, the PV roofing tiles 10 can be individually separated from other PV roofing tiles 10 by non-PV roofing tiles. Preferably, clustering of PV roofing tiles 10 is preferable in order to facilitate the collection and transmission of electricity generated by the PV roofing tiles 10. Also, the roof assembly may include PV roofing tiles 10 with or without a fire suppression member 28 as well as non-PV roofing tiles with or without fire suppression member 28. Any mixture of these four types of roofing tiles may be included in a roof assembly. Additionally, the orientation of PV roofing tiles 10 on a roof may vary from PV roofing tile 10 to PV roofing tile 10 depending on aesthetics as well as optimum positioning for conversion of electromagnetic radiation into electricity. Additionally, the roof assembly can comprise PV roofing tiles 10 which have the fire suppression member 28 in the same or different locations so as to accommodate different aesthetic and functional requirements, depending on what is visible to consumers and where a fire is more likely to initiate and expand to.
While it is preferred that the fire suppression member 28 be located on the flange 14 at the first end 12c of the substrate 12, it is understood that the present invention is not limited to the exact location or mounting method the fire suppression member. The following is a description of alternative embodiments wherein like numerals indicate like elements throughout. Therefore a complete description of each embodiment is omitted and only the differences between the first embodiment and the alternative embodiment are discussed.
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The fire suppression container 34 may also be configured with a propellant under pressure such as CO2, nitrogen gas, or any other non-flammable propellant readily known in the art. As such, when the retaining element 36 is released, the contents of the fire suppression container 34, which are under pressure, are forcibly expelled from the fire suppression container 34 through the openings 32 and down the roof to actively fight the fire hazard. The fire suppressing agent can be a fire fighting foam, liquid, gas, or powder. Preferably, the fire suppressing agent is a liquid fire fighting agent, especially in combination with fire suppression container 34 having a pressurized propellant.
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The positions described above regarding the fire suppression member 28 are not limiting and additional positions are contemplated without departing from the spirit and scope of the invention. For example, the fire suppression member 28 can be arranged along any surface or partial surface of the substrate 12 which is not covered with the PV laminate 18. Regardless of where the fire suppression member 28 is arranged on the substrate 12, the fire suppression member 28 can extend partially along the width of the substrate 12, substantially along the width of the substrate 12, nearly completely along the width of the substrate 12 (the entire width except for the peripheral portions), or completely along the width of the substrate 12. The same possibilities are applicable regarding the extension of the fire suppression member 28 along a dimension which is perpendicular to the width of the substrate 12. The width of the substrate 12 is from left to right in
Additionally, the fire suppression member 28 can also be hidden just beneath the exposed surface of the substrate 12 such that during a fire hazard, the surface would melt away to allow the fire suppression device to activate in an unimpeded manner. Additionally, the fire suppression member 28 can partly extend into a groove 16 of the substrate 12 and partly protrude from the substrate 12, or it can extend from the groove 16 to be flush with a surface of the substrate 12, preferably a front surface 30.
Thus, the present invention permits the safe generation of electricity in rooftops in a versatile manner adaptable to different functional and/or aesthetic requirements.
It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.
The present application claims priority to U.S. Provisional Patent Application No. 61/032,245, which was filed on Feb. 28, 2009, the contents of which are incorporated herein in their entirety.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/US09/35696 | 3/2/2009 | WO | 00 | 8/27/2010 |
Number | Date | Country | |
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61032245 | Feb 2008 | US |