Low-CTE Triple-Pane IGU Structure Without Tempering Warpage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Triple pane insulated glass units (IGUs) face challenges in meeting design constraints such as reduced weight, thickness, and manufacturing cost due to the additional glass layer, and thermal tempering can cause warping and birefringence, degrading optical quality.
Innovation Solution
A multi-layer IGU design with a low coefficient of thermal expansion (CTE) glass layer, typically less than 70×10−7/° C., is used between two thicker glass layers, which can be chemically strengthened or thermally tempered, and optionally coated or patterned, with sealed gas-filled gaps to improve mechanical strength and thermal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a triple pane IGU is used to improve thermal and insulative performance, then solar heat gain coefficient and U-values are improved by 20-30% or more, but weight, thickness, and manufacturing cost increase
Solution Approach 1:
The patent changes the material parameter of the center glass layer by selecting a glass composition with low coefficient of thermal expansion (CTE < 70×10^-7/°C.). This parameter change allows the glass to withstand thermal stresses without requiring thermal tempering, thereby reducing the thickness and weight of the center layer while maintaining triple-pane thermal performance
Solution Approach 2:
The patent uses a composite structure where the center glass layer is made of a specific glass composition (e.g., aluminosilicate or borosilicate glass) with low CTE properties, differentiated from the outer glass layers. This material composition strategy enables the center layer to be thinner and lighter while still providing the necessary thermal and mechanical performance in the triple-pane configuration
2Strength
If the center glass layer is thermally tempered to reduce breakage likelihood, then mechanical strength is improved, but the IGU thickness and weight increase, and manufacturing cost increases
Solution Approach 1:
The patent changes the chemical composition parameter of the glass to achieve low CTE (< 70×10^-7/°C.), which fundamentally alters the glass's thermal stress behavior. This parameter change allows the use of thinner, lighter glass in the center layer without thermal tempering, as the low CTE material inherently resists thermal stress-induced breakage
Solution Approach 2:
The patent extracts the thermal tempering process from the manufacturing sequence by using low CTE glass that does not require thermal tempering to achieve adequate mechanical strength. This removal of the thermal tempering step eliminates the associated weight and thickness increases while maintaining breakage resistance
3Strength
If the center glass layer is thermally tempered to improve mechanical strength, then breakage likelihood is reduced, but optical quality is degraded due to warping and birefringence
Solution Approach 1:
The patent removes the thermal tempering process from the manufacturing sequence by using low CTE glass that inherently resists thermal stress. This extraction eliminates the warping and birefringence defects associated with thermal tempering, thereby preserving the optical quality of the center glass layer while still achieving adequate mechanical strength through material selection
Solution Approach 2:
By changing the glass composition parameter to achieve low CTE, the patent fundamentally alters the glass's response to thermal stress. This parameter change eliminates the need for thermal tempering and prevents the development of warping and birefringence, thereby maintaining high optical quality in the center layer
4Loss of energy
If triple pane IGU is used to improve thermal performance, then insulative U-values are improved, but manufacturing cost increases
Solution Approach 1:
The patent changes the glass composition parameter to low CTE material, which eliminates the requirement for thermal tempering of the center layer. This parameter change removes a complex and costly manufacturing step while maintaining the triple-pane thermal performance, thereby reducing overall manufacturing cost
Solution Approach 2:
The patent extracts the thermal tempering process from the manufacturing sequence for the center glass layer by using low CTE glass that does not require tempering. This removal of the tempering step reduces manufacturing complexity and cost while preserving the insulative performance benefits of the triple-pane configuration
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 low CTE glass layer reduces thermal stress, prevents warping, and lowers manufacturing costs by eliminating the need for thermal tempering, resulting in a thinner, lighter, and more energy-efficient IGU with improved optical quality.
Implementation Method 1
the third glass layer has a coefficient of thermal expansion (CTE) over a temperature range 0-300° C. of less than 70×10−7/° C.
Implementation Method 2
The sheets of glass are spaced apart, and the space between each glass sheet, once sealed, can be filled with an inert gas, such as argon or krypton, or an inert gas mixture. In doing so, the insulative or thermal performance of the IGU can be improved.
Data Source
AI summary
An insulated glass unit is described and includes at least a first glass layer, a second glass layer and a third glass layer disposed therebetween. The third glass layer is separated from the first glass layer and the second glass layer by first and second sealed gap spaces. The third glass layer has a low CTE as compared to the CTE of the first and/or second glass layers. In some instances, the third glass layer has a CTE of less than 70×10−7/° C. over a temperature range of 0-300° C.