Coated Construction Granules for Solar Heat Reduction
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Solution Overview
Problem
Conventional roofing materials, such as asphalt shingles, absorb significant near-infrared radiation, leading to elevated temperatures and heat-island effects, particularly in dark-colored shingles, which increases the need for energy-consuming cooling systems, while existing solutions for improved reflectivity often compromise aesthetics.
Innovation Solution
Development of coated construction granules with a conductive layer and a dielectric layer, capable of reflecting greater than 20% of incident solar radiation and having an emissivity of at least 50%, suitable for use in bituminous construction materials, which can be fabricated using various metals and dielectric materials applied through specific processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional asphalt shingles are used with dark colors for aesthetic appeal, then aesthetic appearance is improved, but solar radiation absorption increases leading to heat-island effects
Solution Approach 1:
The patent applies composite materials by combining a dark-colored granule core with thin-film coatings of metal (aluminum or zinc) and dielectric materials. This composite structure allows the granule to maintain its dark aesthetic appearance while the metal and dielectric layers provide solar radiation reflection, particularly in the near-infrared spectrum, thereby reducing heat absorption without compromising color.
Solution Approach 2:
The patent applies local quality by applying thin-film coatings only to the surface of the granules rather than making the entire granule structure different. The dark color is maintained in the core while the surface layers provide selective solar reflection. This localized application allows the bulk of the granule to retain its aesthetic properties while the surface provides the functional solar reflection capability.
2Object-affected harmful factors
If white or light-colored pigments are applied to enhance solar reflectivity, then solar radiation reflection is improved, but aesthetic appearance deteriorates due to loss of dark color preference
Solution Approach 1:
Instead of using white or light-colored pigments that would compromise aesthetic appearance, the patent uses composite materials consisting of thin-film metal and dielectric layers. These coatings provide effective solar radiation reflection through their optical properties rather than through light color, allowing the granule core to maintain its preferred dark color while achieving the desired reflectivity.
Solution Approach 2:
The patent substitutes the traditional approach of using light-colored pigments (a mechanical/chemical coloring approach) with a thin-film coating system that relies on optical reflection properties of metal and dielectric materials. This substitution allows solar reflection to be achieved through physical optical mechanisms rather than through color, preserving the dark aesthetic appearance.
3Object-affected harmful factors
If metal flakes such as aluminum are adhered to provide radiation-reflective surface, then solar radiation reflection is improved, but aesthetic appearance becomes less pleasing to consumers
Solution Approach 1:
The patent applies local quality by using thin-film coatings of metal rather than adhering discrete metal flakes to the surface. The thin-film approach creates a uniform, smooth surface that maintains aesthetic appeal, whereas metal flakes would create a textured, visually distracting surface. The metal layer is applied in a controlled thin-film manner that provides reflection functionality while preserving surface smoothness and visual uniformity.
Solution Approach 2:
The patent employs flexible shells and thin films by applying metal and dielectric materials as thin-film coatings on the granule surface. This thin-film approach provides the solar reflection functionality of metal while creating a smooth, uniform surface that maintains aesthetic appearance. The thin-film structure allows the metal to be integrated into the granule surface rather than appearing as separate flakes, thereby preserving visual appeal.
4Ease of manufacture
If conventional roofing materials are used, then manufacturing simplicity is maintained, but energy consumption increases due to heat-island effects requiring cooling systems
Solution Approach 1:
The patent applies composite materials by integrating thin-film metal and dielectric coatings onto conventional granule cores. This approach maintains the simplicity of conventional granule manufacturing while adding the solar reflection functionality through subsequent coating processes. The composite structure allows existing manufacturing infrastructure to be utilized with minimal modification, preserving ease of manufacture while reducing energy consumption through reduced heat-island effects.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The coated granules effectively reduce solar heat absorption, mitigating heat-island effects while maintaining an aesthetically pleasing appearance, as they reflect a substantial amount of solar radiation and emit energy efficiently.
Implementation Method 1
the coated construction granule reflecting greater than about 20% of incident solar radiation
Implementation Method 2
the bituminous construction material having an emissivity of at least about 50%
Data Source
AI summary
Provided are construction material granules. In one embodiment, the granules include a core enclosed by a layer comprising a conductive material and a layer comprising a dielectric material. Also provided are related methods of constructing such materials.