Vacuum Insulated Panel Passivation for Stable Vacuum Life
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Solution Overview
Problem
Vacuum insulated panels suffer from loss of vacuum level over time due to UV-induced and elevated temperature-induced outgassing from glass substrates, which existing technologies have not effectively addressed, and existing technologies have not addressed, and existing vacuum insulated panels have not effectively addressed the challenge of UV-induced and elevated temperature induced issues.
Innovation Solution
A vacuum insulated panel comprising a dielectric passivation layer is applied to the vacuum insulated panel which comprises a dielectric passivation layer on the first glass substrate, a second glass substrate, and a plurality of spacers between the substrates, with a seal partially between the substrates, and a low-emissivity coating on the second glass substrate, where the dielectric passivation layer is transparent and has a refractive index no greater than the first glass substrate, reducing outgassing without significantly affecting visible transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a vacuum insulated panel uses glass substrates without passivation layer, then the panel provides good initial vacuum insulation, but the vacuum level degrades over time due to UV-induced and elevated temperature-induced outgassing from the glass substrates
Solution Approach 1:
A dielectric passivation layer is introduced as an intermediary between the glass substrate and the vacuum cavity. This passivation layer acts as a barrier that prevents outgassing from the glass substrate while allowing the vacuum cavity to maintain its insulation properties. The passivation layer is specifically designed to be transparent to visible light and have appropriate optical properties to minimize impact on the panel's overall performance.
Solution Approach 2:
The passivation layer is applied to the glass substrate before the panel is assembled and evacuated. This preliminary protective action prevents UV-induced and elevated temperature-induced outgassing from occurring in the first place, rather than attempting to address the outgassing problem after the panel is assembled. The passivation layer is designed to block the release of hydrogen, oxygen, and carbon monoxide that would otherwise degrade the vacuum.
2Reliability
If a dielectric passivation layer is applied to the first glass substrate, then outgassing is reduced and vacuum level stability is improved, but the panel structure becomes more complex
Solution Approach 1:
The passivation layer is designed with specific optical parameters to minimize its impact on the panel's overall performance. The layer is made transparent to visible light and its refractive index is matched to the glass substrate to reduce reflections. By optimizing these parameters, the passivation layer provides its protective function while having minimal impact on the panel's optical and thermal properties, thus reducing the effective complexity increase.
3Reliability
If the dielectric passivation layer has high refractive index, then outgassing protection is effective, but visible transmission is significantly affected
Solution Approach 1:
The passivation layer's refractive index is carefully selected and controlled to balance two competing requirements: providing effective outgassing protection and maintaining good visible transmission. The refractive index is matched to the glass substrate to minimize optical reflections and maximize light transmission. This parameter optimization allows the passivation layer to perform its protective function while having minimal impact on the panel's optical properties.
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 dielectric passivation layer reduces outgassing from the glass substrates, extending the panel's useful life and maintaining desirable u-factors by preventing hydrogen, oxygen, and carbon monoxide outgassing, thus enhancing the panel's insulation properties.
Implementation Method 1
UV light over the spectral range of 330 nm to 450 nm can solarize soda lime silicate float glass and cause embedded water vapor, excess hydrogen and carbon dioxide and carbon monoxide to outgas from the glass surface or bulk material
Implementation Method 2
reducing radiative energy with a low-emissivity (low-E) coating provided on one of the 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 at least one passivation layer for reducing outgassing from a glass substrate, in order to improve lifespan of the vacuum insulating panel.