Window Sash Heat-Conducting Element Condensation Prevention

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Solution Overview

Problem

Vacuum glazing in doors and windows is prone to condensation and mold formation due to large temperature differences, and existing solutions like thermal coupling elements may not sufficiently transfer heat to prevent condensation, especially at low outside temperatures.

Innovation Solution

A window or door sash design with a heat-conducting element between the glazing bead and rebate base, where the heat-conducting element is positioned to shift isotherms away from the vacuum insulating glazing surface, using materials with high thermal conductivity like aluminum, and ensuring a minimal distance of 15 mm or less between the glass edge and rebate base.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If vacuum glazing is used to achieve low Ug values, then thermal insulation is improved, but the risk of condensation and mold formation increases due to low surface temperature at the transition area

Engineering Contradiction:
Improvethermal insulationVSAvoidcondensation risk
Core Design Contradiction:
Loss of energyVSObject-affected harmful factors

Solution Approach 1:

A heat-conducting element is introduced as an intermediary component between the glazing bead and the rebate base. This element acts as a thermal bridge that actively conducts heat from the warmer interior side to the colder transition area, preventing condensation without compromising the vacuum glazing's insulation performance.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The heat-conducting element is strategically positioned only in the transition area where condensation risk exists, rather than throughout the entire frame. This localized approach provides thermal enhancement precisely where needed while maintaining energy efficiency elsewhere.

Inventive Principle:
Principle #3Local quality

2Object-affected harmful factors

If thermal coupling elements are added to prevent condensation, then condensation risk is reduced, but the heat transfer may still be insufficient at low outside temperatures

Engineering Contradiction:
Improvecondensation riskVSAvoidheat transfer effectiveness
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent specifies that the heat-conducting element must have high thermal conductivity, quantified as at least 15 W/(mK). This parameter change ensures sufficient heat transfer capacity even under extreme temperature differences, making the condensation prevention reliable across all operating conditions.

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If the distance between glass edge and rebate base is reduced to 15 mm or less, then isotherms are shifted away from the glazing surface, but the structural design becomes more constrained

Engineering Contradiction:
Improvecondensation formationVSAvoidstructural design constraints
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent establishes a specific geometric parameter: the distance between the glass edge and rebate base must be 15 mm or less. This parameter change fundamentally alters the thermal field distribution, shifting isotherms away from the vulnerable glazing surface and into the rebate space where they cannot cause condensation.

Inventive Principle:
Principle #35Parameter changes

4Power

If high thermal conductivity materials are used in the heat-conducting element, then heat transfer efficiency is improved, but material selection becomes more limited

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidmaterial selection flexibility
Core Design Contradiction:
PowerVSAdaptability or versatility

Solution Approach 1:

The patent sets a minimum thermal conductivity threshold of 15 W/(mK) for the heat-conducting element material. This parameter specification ensures adequate heat transfer performance while still allowing flexibility in material selection among various metals and metal alloys that meet or exceed this threshold.

Inventive Principle:
Principle #35Parameter changes

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

Effectively reduces the risk of condensation and mold formation by efficiently transferring heat from the room to the vacuum insulating glazing surface, preventing isotherms from running along the glazing surface and promoting condensation formation.

Implementation Method 1

the heat-conducting element comprises at least one support part with which the heat element rests on the rebate base... efficiently transferring heat from the room to the vacuum insulating glazing surface

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

an insulating glazing unit received in the rebate space at the end face, which comprises at least two glass panes, the space between which is subjected to a negative pressure

Methodology Applied
Scientific EffectVacuum insulation: Vacuum

Data Source

PatentEP4202169B1Window or door leaf and window or door comprising same
Publication Date: 2025.10.01 REHAU IND SE & CO KG
  • EP4202169B1 patent drawingFigure 1
  • EP4202169B1 patent drawingFigure 2
  • EP4202169B1 patent drawingFigure 3

AI summary

The present invention relates to a window or door sash (1) comprising (a) a sash frame (2) formed from sections of a window or door sash profile (3), which has a rebate base (8) and an outer overlap (6), (b) a glazing bead (10) anchored in a glazing bead groove (9) of the window or door sash profile (3), which together with the rebate base (8) and the outer overlap (6) forms a rebate space (11) that is at least partially open on one side, wherein the glazing bead (10) comprises at least one glazing seal (15, 15'); and (c) an insulating glazing unit (12) received at the end face of the rebate space (11), which comprises at least two glass panes (13, 13') whose space between them is pressurized and which has a glass edge (14) facing the rebate base (8);comprising, wherein the at least one glass seal (15, 15') bears at least partially against the glass pane (13') facing it, wherein the window or door sash (1) is characterized according to the invention in that, viewed in cross-section of the window or door sash (1), the distance between the glass edge (14) and the rebate base (8) is at most 15 mm, preferably at most 10 mm. Furthermore, the present invention also relates to a window (100) or a door comprising a frame (4) or a jamb and such a window or door sash (1) received therein in the closed state of the window (100) or the door.