Interference Filter Coating for Angle-Stable Orange Solar Glazing
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Solution Overview
Problem
Current solar energy systems face challenges in architectural integration due to their dark appearance and inability to completely hide technical components, which limits their visual appeal and potential efficiency.
Innovation Solution
A multi-layered interferential coating is applied to the inner side of solar glazing, reflecting a narrow spectral band of visible light while maintaining transparency for the solar spectrum, using non-absorbing materials like ZnO, SiO2, Al2O3, and MgF2, to achieve an orange color that masks technical parts and ensures high solar transmittance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a multi-layered interferential coating is applied to achieve orange color and hide technical components, then the architectural integration and visual appeal are improved, but the solar transmittance may be reduced
Solution Approach 1:
The patent applies a multi-layered interferential coating that reflects orange light (wavelengths around 580-620 nm) while transmitting other wavelengths. This selective color reflection achieves the desired orange appearance to mask technical components, while the coating is designed to maintain high transmittance in the solar spectrum range, thus resolving the contradiction between aesthetic appearance and energy transmission.
Solution Approach 2:
The coating design optimizes layer thicknesses and refractive indices to create a narrowband reflection peak in the orange region while maintaining high transmission in the solar spectrum. By precisely controlling optical parameters (layer thickness, refractive index ratios), the system achieves both aesthetic goals and energy efficiency requirements.
2Loss of energy
If the glazing reflects a narrow spectral band to maintain solar transmittance, then the efficiency of solar systems is maintained, but the ability to completely hide technical components is reduced
Solution Approach 1:
The interferential coating reflects orange light which masks the visual appearance of technical components behind the glazing. The orange reflection provides sufficient camouflage for most architectural applications while the narrow spectral bandwidth ensures minimal impact on solar energy transmission, balancing aesthetic requirements with energy efficiency.
3Loss of energy
If the coating uses non-absorbing materials to maintain transparency, then the solar transmittance is improved, but the manufacturing complexity increases
Solution Approach 1:
The coating uses alternating layers of materials with different refractive indices (e.g., TiO2/SiO2, ZnO/SiO2, Al2O3/SiO2) to create the interferential effect. These composite multi-layer structures provide the necessary optical functionality while using non-absorbing dielectric materials to maintain high solar transmittance, achieving both performance and material compatibility requirements.
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 provides a stable orange color with minimal color variation at different viewing angles, enhancing architectural integration and maintaining high solar system efficiency with limited efficiency loss compared to uncoated glass.
Implementation Method 1
a multi-layered interferential coating is applied to the inner side of solar glazing, reflecting a narrow spectral band of visible light
Implementation Method 2
using non-absorbing materials like ZnO, SiO2, Al2O3, and MgF2, to achieve an orange color that masks technical parts and ensures high solar transmittance
Data Source
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AI summary
Solar glazing unit, suitable for photovoltaic modules and solar thermal collectors, comprising a substrate delimited by two main faces and a multi-layered interference filter also delimited by two main faces, one main face of said substrate being adapted to be in contact with an incident medium, the other main face being in contact with a main face of said interference filter, the other main face of said interference filter being adapted to be in contact with an exit medium; said incident medium having a refractive index ninc = 1, said substrate having a refractive index nsubstrate defined as follows : 1.45 ≤ nsubstrate ≤ 1.6 at 550 nm, and said exit medium having a refractive index nexit = 1 or defined as follows 1.45 ≤ nexit ≤ 1.6 at 550 nm; and wherein said unit is designed in such a way that the CIE colour stability ΔE*Norm, as observed under daylight illumination CIE D65 at higher angles of reflection Θr (Θr > 10°), is less than 15 or ΔE*Norm ≤ (Θr / 3°) for 10° < Θ ≤ 60°.