Vip panel with surface corrugations, wall element and thermal insulation enclosure including such a panel

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Solution Overview

Problem

The fragility of the barrier casing in Vacuum Insulating Panels (VIP) makes them susceptible to compressive and bending forces, leading to degradation of gas barrier properties and reduced longevity, limiting their use in thermal insulation applications.

Innovation Solution

A VIP panel design featuring a porous material resistant to compression, with a gas-tight barrier envelope that includes a first support surface with undulations forming outward bosses, guiding the barrier material to reduce the risk of micro-rupture and maintain integrity under atmospheric pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a thin flexible barrier envelope is used to maintain vacuum in PIV panels, then the panel achieves high insulation performance and reduced thickness, but the envelope becomes fragile and susceptible to compressive and bending forces, leading to degradation of gas barrier properties

Engineering Contradiction:
Improvethermal insulation performanceVSAvoidgas barrier integrity
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The support surface is designed with undulations featuring rounded bosses instead of sharp edges. This curvature distributes stress evenly across the barrier envelope, preventing stress concentration and micro-ruptures while maintaining the thin-envelope design for high insulation performance

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The undulating support surface with rounded bosses is pre-formed to anticipate and cushion the compressive forces that will act on the barrier envelope during vacuum maintenance. This pre-cushioning prevents direct transmission of harmful forces to the thin envelope

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If the porous material core shrinks under atmospheric pressure, then the barrier envelope experiences stress and forms wrinkles, but the shrinkage is necessary to maintain vacuum tightness

Engineering Contradiction:
Improvevacuum tightnessVSAvoidsurface appearance and envelope integrity
Core Design Contradiction:
ReliabilityVSShape

Solution Approach 1:

Rounded bosses on the support surface guide the barrier envelope to form smooth undulations rather than sharp wrinkles. The curved geometry allows the envelope to accommodate core shrinkage while maintaining aesthetic appearance and preventing stress concentration that could lead to micro-ruptures

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The support surface geometry is specifically designed with controlled undulation parameters (amplitude, wavelength, boss radius) to optimize the balance between accommodating core shrinkage and maintaining envelope integrity. The rounded boss radius is specifically tuned to prevent stress concentration

Inventive Principle:
Principle #35Parameter changes

3Shape

If grooves are formed in the porous material to take up excess film, then the appearance of wrinkles is limited, but weaknesses form at the intersections of grooves and microscopic rupture risks increase due to shear forces

Engineering Contradiction:
Improvewrinkle appearanceVSAvoidenvelope durability
Core Design Contradiction:
ShapeVSReliability

Solution Approach 1:

The invention replaces angular groove intersections with rounded boss undulations. This curvature eliminates the stress concentration zones at groove intersections where weaknesses would form, while still providing the necessary film accommodation through the undulating surface geometry

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The invention converts the harmful shear forces that cause micro-ruptures at groove intersections into beneficial distributed compressive forces along the rounded boss undulations. The rounded geometry transforms stress concentration into stress distribution, improving envelope durability

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 design enhances the durability and longevity of VIP panels by preventing micro-rupture and maintaining gas tightness, allowing for effective thermal insulation with reduced thickness and improved aesthetic appearance.

Implementation Method 1

elementary panels of the PIV type comprise an insulating porous core material maintained under vacuum by a barrier envelope guaranteeing gas tightness

Methodology Applied
Scientific EffectVacuum: Vacuum

Implementation Method 2

the barrier envelope defining the outer layer of the panel placed under atmospheric pressure

Methodology Applied
Scientific EffectPressure difference: Pressure Gradient

Implementation Method 3

the first portion of the barrier envelope extending along the first support surface and being deformed to conform to said relief with rounded top projections in correspondence with the bosses

Methodology Applied
Scientific EffectStress distribution:

Implementation Method 4

guided in bending by the bosses, which makes it possible to significantly reduce the risk of micro-rupture/degradation by shearing

Methodology Applied
Scientific EffectBending: Deformation

Implementation Method 5

the barrier casing is stressed from the manufacturing stage due to the shrinkage of the porous material core

Methodology Applied
Scientific EffectShrinkage: Thermal Contraction

Implementation Method 6

subjecting the exterior of the envelope to atmospheric pressure

Methodology Applied
Scientific EffectAtmospheric pressure: Pressure Increase

Data Source

PatentEP3018261B1Vip panel with surface corrugations, wall element and thermal insulation enclosure including such a panel
Publication Date: 2017.08.16 ELECTRICITE DE FRANCE
  • EP3018261B1 patent drawingFigure 1~2A
  • EP3018261B1 patent drawingFigure 2B~3B
  • EP3018261B1 patent drawingFigure 4~5

AI summary

The heat-insulating panel (3) of the PIV type comprises an insulating core (1) including a porous material resistant to compression and a gas-tight barrier envelope (2) making it possible to maintain an internal vacuum and which encloses the insulating core. A flexible portion (5) of the envelope covers one of the main faces (4a) of the porous material and extends along a support surface to conform according to a relief of this support surface, forming an undulation with projections (5a) with a rounded top. The projections (5a) correspond to bosses of the support surface underlying the flexible portion (5). The bosses can be formed directly on the face (4a) of the porous material.