Solar Mirror Coating Stack for High-Temperature Silver Protection
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Solution Overview
Problem
Conventional mirror technologies for concentrated solar power systems face issues with environmental concerns due to wet chemical waste disposal and limitations in processing high-temperature treatments, which affect the longevity and reflectivity of silver-coated glass substrates.
Innovation Solution
A method for creating a reflective article involving a transparent glass substrate with a basecoat, primary reflective coating, anti-corrosion coating, and inorganic protective coating, allowing for heating to high temperatures without damaging the silver layer, thereby enhancing reflectance and extending the article's lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If wet chemical process is used to deposit silver coating, then reflectance of solar radiation is improved, but environmental harm increases due to waste disposal
Solution Approach 1:
The patent extracts and eliminates the harmful wet chemical process from the manufacturing system. Instead of using silver nitrate solutions and chemical precipitants, the invention employs physical vapor deposition methods to deposit reflective metal layers, thereby removing the source of chemical waste while maintaining the reflective function.
Solution Approach 2:
The patent replaces the chemical deposition mechanism with a physical deposition mechanism. Rather than using wet chemical reactions to precipitate silver, the invention uses vacuum deposition or sputtering techniques to physically deposit metal layers onto the glass substrate, substituting chemical processes with physical ones.
2Illumination intensity
If silver layer is deposited by wet chemistry, then reflectance is improved, but processing temperature is limited due to damage to silver layer
Solution Approach 1:
The patent applies preliminary protective actions by depositing multiple layers in a specific sequence before any thermal processing occurs. The reflective metal layer is deposited first, followed by protective dielectric layers that will later enable high-temperature processing without damaging the underlying metal coating.
Solution Approach 2:
The patent creates a composite coating structure consisting of multiple materials with complementary properties. The reflective metal layer provides optical functionality, while overlying dielectric layers provide thermal stability and chemical protection, allowing the composite structure to withstand high temperatures that would individually damage the metal layer.
3Reliability
If copper layer is added to protect silver from corrosion, then durability is improved, but environmental harm increases due to wet chemical waste
Solution Approach 1:
The patent replaces the wet chemical copper deposition process with a physical vapor deposition process. Instead of using copper sulfate solutions and chemical displacement reactions, the invention uses vacuum deposition or sputtering to deposit copper and subsequent protective layers, eliminating the associated chemical waste while achieving the same protective function.
4Reliability
If multiple coating layers are added to protect reflective layer, then durability is improved, but device complexity increases
Solution Approach 1:
The patent segments the protective function into multiple specialized layers, each performing a specific role: the reflective metal layer provides optical functionality, the first dielectric layer provides immediate protection and adhesion, the second dielectric layer provides additional environmental barrier, and the polymer layer provides mechanical protection and weathering resistance. This segmentation allows each layer to be optimized for its specific function.
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 method improves the reflectance of electromagnetic radiation and allows for heat treatment or bending of the coated substrate, extending its commercial life and reducing environmental impact by eliminating the need for wet chemical processes.
Implementation Method 1
a primary reflective coating formed over at least a portion of the basecoat... the reflective article has a higher reflectance in a selected range of electromagnetic radiation
Implementation Method 2
an inorganic protective coating formed over at least a portion of the primary reflective coating... to protect the silver layer
Implementation Method 3
heating the coated substrate to at least a softening temperature of the glass substrate... allows for heating to high temperatures without damaging the silver layer
Data Source
AI summary
A reflective article, such as a solar mirror, includes a highly transparent substrate having a first major surface and a second major surface. At least one reflective coating is formed over at least a portion of one of the surfaces, e.g., the second major surface (or, alternatively, the first major surface). The reflective coating includes at least one metallic layer. An encapsulation structure can be formed over at least a portion of the second reflective coating.