Double-Glazed Facade Venting With a Breathable Membrane

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Solution Overview

Problem

Existing building façade ventilation systems are complex, maintenance-intensive, and vulnerable to contamination, with control mechanisms requiring frequent cleaning and prone to condensation due to temperature fluctuations.

Innovation Solution

A building façade element with a frame separating outer and inner glazing, featuring a ventilation opening with a breathable membrane that allows permanent ventilation and prevents contamination, using a composite material with specific water vapor and air permeability properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a control mechanism with opening/closing ventilation is used, then condensation can be prevented, but the structure becomes complex and maintenance-intensive

Engineering Contradiction:
Improvecondensation preventionVSAvoidcontrol mechanism structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the control mechanism entirely from the ventilation system. Instead of using an opening/closing shutter system, the invention employs a permanently open ventilation opening that allows continuous air flow through the intermediate space, thereby preventing condensation without requiring any moving parts or control systems.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The ventilation system operates autonomously without external control. The breathable membrane automatically regulates air and vapor passage based on pressure differentials and humidity gradients, eliminating the need for motors, sensors, or manual operation while maintaining effective condensation prevention.

Inventive Principle:
Principle #25Self-service

2Reliability

If a ventilation opening is opened to ventilate the space, then condensation is prevented, but dirt can enter the space

Engineering Contradiction:
Improvecondensation preventionVSAvoidcontamination
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent employs a breathable membrane made of porous material with specific pore size and distribution. This membrane allows air molecules and water vapor to pass through while blocking larger particulate matter such as dust and dirt. The porous structure enables selective permeability based on particle size, maintaining ventilation effectiveness while preventing contamination.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The breathable membrane is constructed as a composite material combining hydrophobic and hydrophilic properties. The composite structure features a hydrophobic outer layer that repels liquid water and particulates, while an inner hydrophilic layer allows water vapor transmission. This composite design simultaneously achieves contamination prevention and effective ventilation.

Inventive Principle:
Principle #40Composite materials

3Object-affected harmful factors

If a breathable membrane is used, then contamination is prevented, but the membrane requires specific manufacturing precision

Engineering Contradiction:
Improvecontamination preventionVSAvoidmembrane pore structure
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent specifies optimal ranges for membrane parameters rather than exact values, allowing manufacturing flexibility. The breathable membrane is designed with pore sizes in a specific range (0.08-100 μm) and water vapor transmission rates within defined boundaries (35,000-65,000 g/m²/24h). These parameter ranges accommodate normal manufacturing variations while ensuring functional performance.

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

The system provides efficient, permanent ventilation that prevents condensation and contamination, eliminating the need for control mechanisms and reducing maintenance, while ensuring optimal insulation and sun protection.

Implementation Method 1

a breathable membrane that allows permanent ventilation and prevents contamination

Methodology Applied
Scientific EffectVapor permeability: Permeation

Implementation Method 2

the breathable membrane has a water vapor transmission rate in a range of 35,000 to 65,000 g/m2/24h

Methodology Applied
Scientific EffectWater vapor transmission: Permeation

Implementation Method 3

The breathable membrane has an air permeability of ≥ 10 L/m2

Methodology Applied
Scientific EffectAir permeability: Permeation

Implementation Method 4

The breathable membrane has an average pore diameter in a range of 0.08 to 100 μm

Methodology Applied
Scientific EffectPore diameter filtration: Filter (physical)

Implementation Method 5

The breathable membrane is water-repellent, with a water column of at least 5 m

Methodology Applied
Scientific EffectHydrophobicity: Hydrophobe

Data Source

PatentEP3835505B1Building facade element, connection element and use of a membrane for ventilating an intermediate space between an external and internal glazing
Publication Date: 2025.09.24 AEPLI METALLBAU AG
  • EP3835505B1 patent drawingFigure 1
  • EP3835505B1 patent drawingFigure 2
  • EP3835505B1 patent drawingFigure 3

AI summary

Building facade element (1) with a frame (5) in which an outer glazing (3) and an inner glazing (4) are arranged, wherein the outer glazing (3) and the inner glazing (4) are spaced apart from each other in such a way that a space (2) is formed between them, wherein the space (2) is permanently connected to the outside air via a ventilation opening (51), and wherein the ventilation opening (51) is provided with a breathable membrane (62).