Chemically Strengthened Ceramic Spacers for Vacuum Panels
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Solution Overview
Problem
Metal spacers in vacuum insulated panels face limitations such as plastic deformation, micro-cracking, and increased thermal conductivity due to mismatched thermal expansion coefficients with glass substrates, leading to reduced insulation performance and aesthetic issues.
Innovation Solution
Employing ceramic spacers with compressive and tensile stress regions, chemically strengthened via ion exchange processes, to match the thermal expansion of glass substrates and enhance structural integrity and transparency, thereby reducing heat transfer and visibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal spacers are used in vacuum insulated panels, then the spacers provide structural support and maintain vacuum integrity, but they cause thermal conduction increase and aesthetic degradation due to visible presence and thermal expansion mismatch
Solution Approach 1:
The patent changes the material parameter from metal to ceramic, specifically selecting ceramic materials with thermal conductivity between 0.5-2.0 W/mK (compared to metal's 14.6 W/mK) and coefficient of thermal expansion matching glass substrates (7.0-9.0×10^-6/K). This parameter change resolves the contradiction by maintaining structural strength while dramatically reducing thermal conduction and eliminating thermal expansion mismatch issues.
Solution Approach 2:
The patent applies color/transparency changes by using ceramic spacers that are substantially transparent or translucent in the visible spectrum, matching the aesthetic appearance of glass substrates. This allows the spacers to maintain structural support function while becoming visually imperceptible, resolving the aesthetic degradation issue.
2Strength
If metal spacers are used in vacuum insulated panels, then the spacers provide structural support, but they cause micro-cracking and reliability reduction due to coefficient of thermal expansion mismatch with glass substrates
Solution Approach 1:
The patent changes the coefficient of thermal expansion parameter of the spacer material to match the glass substrate (7.0-9.0×10^-6/K for ceramic vs. metal's 15-20×10^-6/K). This parameter matching eliminates differential thermal expansion stresses that cause micro-cracking at the spacer-glass interface, thereby improving reliability while maintaining structural support.
3Loss of energy
If larger spacer separation distance is used, then the insulation performance is improved by reducing thermal conduction through spacers, but the vacuum stress loading support capability is reduced
Solution Approach 1:
The patent changes the material composition to ceramic with optimized mechanical properties (compressive strength ≥300 MPa, elastic modulus 60-80 GPa) that provide sufficient vacuum load support capability. This allows the use of larger spacer separation distances (50-100 mm) to reduce thermal conduction losses while the ceramic material's mechanical strength maintains adequate vacuum integrity.
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 ceramic spacers provide improved insulation performance by maintaining structural integrity under vacuum and thermal stress, reducing visible presence, and enhancing aesthetic appeal while maintaining low thermal conductivity.
Implementation Method 1
chemically strengthened via ion exchange processes
Implementation Method 2
match the thermal expansion of glass substrates
Implementation Method 3
Providing a vacuum in the space between the substrates reduces conduction and convection heat transport
Implementation Method 4
Providing a vacuum in the space between the substrates reduces conduction and convection heat transport
Data Source
AI summary
A vacuum insulating panel includes first and second substrates (e.g., glass substrates), a hermetic edge seal, a pump-out port, and spacers sandwiched between at least the two substrates. The gap between the substrates may be at a pressure less than atmospheric pressure to provide insulating properties. The vacuum insulating panel may include ceramic (e.g., aluminosilicate glass) spacers, which may be chemically strengthened.