Low-E Window Coating Structure for Matte Gray Heat Insulation
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Solution Overview
Problem
Existing window materials lack effective heat resistance, moisture resistance, and abrasion resistance while maintaining visible light transmittance and reflectivity for energy-saving purposes, particularly in achieving a matte gray appearance.
Innovation Solution
A functional building material for windows featuring a low-emissivity coating with a multilayer structure comprising a low-emissivity layer, a light-absorbing metal layer, and dielectric layers, including chromium nitride, which selectively reflects far-infrared rays and provides excellent heat insulation, while achieving a matte gray color index and suitable visible light transmittance and reflectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a low-emissivity layer containing silver is deposited to reflect infrared radiation and preserve energy, then energy-saving effect is improved, but the glass becomes susceptible to oxidation and reduced durability
Solution Approach 1:
A dielectric layer is introduced as an intermediary between the silver low-emissivity layer and the external environment. This dielectric layer serves as a protective barrier that prevents oxidation of the silver while maintaining the infrared reflection capability, thus preserving both energy-saving performance and durability
Solution Approach 2:
The patent creates a composite structure combining the silver low-emissivity layer with a dielectric layer. This composite material approach allows the silver to provide thermal reflection while the dielectric material provides oxidation resistance, achieving both energy efficiency and long-term reliability
2Reliability
If a dielectric layer is deposited to protect the low-emissivity layer from oxidation, then oxidation resistance is improved, but visible light transmittance may be reduced
Solution Approach 1:
The patent optimizes the thickness and refractive index parameters of the dielectric layer to achieve the right balance. By carefully controlling these parameters, the dielectric layer provides adequate oxidation protection while maintaining sufficient visible light transmittance for practical window applications
3Temperature
If multiple layers are added to achieve matte gray appearance and improve heat resistance, then heat resistance and appearance are improved, but device complexity increases
Solution Approach 1:
The patent segments the coating into distinct functional layers: a low-emissivity layer for infrared reflection, a dielectric layer for oxidation protection, and additional layers for heat resistance and matte gray appearance. Each layer performs a specific function, allowing the complex performance requirements to be met through modular layer design rather than a single complex material
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 material exhibits excellent heat resistance, moisture resistance, and abrasion resistance, while maintaining energy-saving properties by minimizing heat transfer and achieving a matte gray appearance, thus reducing energy consumption.
Implementation Method 1
a low-emissivity layer which selectively reflects far-infrared rays among the solar radiant rays
Implementation Method 2
exhibit excellent heat insulating performance by Roy (Low-e; low emissivity) effect which results from the low emissivity characteristics of the low-emissivity coating
Implementation Method 3
a lower light-absorbing layer, a light-absorbing metal layer wherein the lower-light absorbing layer comprises a chromium nitride
Implementation Method 4
a dielectric layer is deposited as an oxidation-resistant membrane on the upper and lower portions of the low-emissivity layer
Data Source
Figure 1~2
Figure 3
AI summary
Provided is a matte gray functional building material for windows, comprising: a transparent glass substrate; and a low-emissivity coating formed on one surface of the transparent glass substrate, wherein the low-emissivity coating comprises a lower light-absorbing layer, a light-absorbing metal layer, and a low-emissivity layer, the lower light-absorbing layer comprises chromium nitride and has a color index a* value of -5 to 5 and a color index b* value of -5 to 5, which are measured by means of a colorimeter for visible light transmitting color, the other surface of the transparent glass substrate, on which the low-emissivity coating is not coated, has a color index a* value of -5 to 5, a color index b* of -5 to 5, which are measured by means of a colorimeter for reflected color, and has a visible transmittance of 20-60%, and the visible reflectivity of the other surface of the transparent glass substrate, on which the low-emissivity coating is not coated, is 1-15%.