Solar selective coating
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Solution Overview
Problem
Current solar selective coatings for thermal solar collector systems face challenges in maintaining long-term stability at high temperatures and in atmospheric environments, experiencing corrosion and deterioration, which affects their optical properties and longevity.
Innovation Solution
A solar selective coating with a sandwich construction comprising a metallic adhesion layer of refractory metals like Molybdenum and Titanium, providing high IR reflection, corrosion resistance, and acting as a diffusion barrier, along with an absorber and antireflection stack, to enhance adhesion and reduce thermal emittance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a multi-layered coating is used to achieve high solar radiation absorption and low infrared radiation loss, then the optical properties are improved, but the long-term stability at high temperatures and in atmospheric environments deteriorates due to corrosion and layer deterioration
Solution Approach 1:
The coating is divided into functionally distinct layers: an adhesion layer for substrate bonding, an absorber stack for solar radiation absorption, and an antireflection stack for minimizing infrared radiation loss. This segmentation allows each layer to be optimized for its specific function while working together to solve the contradiction between optical performance and long-term stability.
Solution Approach 2:
The patent employs composite material structures where multiple materials with different properties are combined in a layered architecture. The adhesion layer uses materials with high thermal stability and corrosion resistance, the absorber stack uses materials optimized for solar absorption, and the antireflection stack uses materials tailored for infrared management. This composite approach enables simultaneous achievement of high optical performance and long-term environmental stability.
2Duration of action of stationary object
If the coating is exposed to high temperatures and atmospheric environments for long-term use, then the operational lifespan is extended, but corrosion and deterioration of the coating layers occur, changing optical properties
Solution Approach 1:
The adhesion layer is applied first as a preliminary protective barrier before the absorber and antireflection layers are deposited. This preliminary layer is specifically designed with high corrosion and oxidation resistance to protect the underlying layers from environmental degradation, preventing corrosion and deterioration before they can affect the optical properties.
Solution Approach 2:
The adhesion layer creates a protective environment for the underlying coating layers by resisting oxidation and corrosion from the atmospheric environment. This effectively shields the sensitive absorber and antireflection layers from harmful atmospheric interactions, maintaining their optical properties over extended periods at high temperatures.
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 solution achieves improved corrosion protection, reduced optical property degradation, and extended lifespan of the coating, maintaining high absorption and low thermal emittance even in harsh environments, thereby enhancing the efficiency and durability of solar energy conversion.
Implementation Method 1
The adhesion layer comprises a metallic layer configured with an amorphous disordered structure... High IR reflection - in order to achieve high emission characteristics for the solar selective coating
Implementation Method 2
solar absorbers which convert solar radiation into heat through photo-thermal conversion
Implementation Method 3
Diffusion barrier at the operational temperature levels - in order to reduce the diffusion of elements from the substrate into the absorber layers
Data Source
Figure 1
Figure 2~2B
Figure 3~3B
AI summary
An object is achieved by a solar selective coating to be deposited on a substrate, which solar selective coating comprises an adhesion layer, an absorber stack comprising at least one absorber layer, and an antireflection stack comprising at least one antireflection layer in a sandwich construction. The sandwich construction is configured with the adhesion layer deposited onto the substrate, the absorber stack deposited on the adhesion layer, and the antireflection stack deposited on the absorber stack. The adhesion layer comprises a metallic layer comprising molybdenum and titanium.