Building Envelope Airtightness Testing via Pressure Modulation
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Solution Overview
Problem
Conventional methods for testing airtightness of building envelopes are complex, time-consuming, and costly, requiring large equipment and elaborate procedures, making them economically unviable for widespread use.
Innovation Solution
A method involving an air flow generator and differential pressure transducer to modulate airflow and measure pressure modulation amplitude, allowing for simplified and automated assessment of airtightness without the need for external pressure measurement, utilizing existing ventilation systems and reducing sensitivity to wind pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional blower door testing is used to measure building airtightness, then measurement precision is improved, but device complexity and testing time increase significantly
Solution Approach 1:
The patent extracts the essential measurement function from the complex blower door system by using only a differential pressure transducer to measure pressure modulation, eliminating the need for complex airflow measurement equipment and calibration systems while maintaining measurement capability through a simplified approach
Solution Approach 2:
The patent replaces the mechanical blower door system with an electrical/electronic solution using a differential pressure transducer and electronic modulation of the air flow generator, substituting mechanical measurement components with electronic sensors and signal processing
2Measurement precision
If conventional blower door testing is used to measure building airtightness, then measurement precision is improved, but testing time increases
Solution Approach 1:
The patent applies periodic modulation to the air flow generator, switching between different flow rates in a periodic manner to create pressure oscillations that can be measured by the differential pressure transducer, enabling rapid measurement without requiring prolonged steady-state testing
Solution Approach 2:
The patent uses feedback by monitoring the pressure modulation signal from the differential pressure transducer and using it to calculate the building airtightness parameter, enabling real-time measurement and immediate results without lengthy data collection periods
3Measurement precision
If conventional blower door testing is used to measure building airtightness, then measurement precision is improved, but ease of operation deteriorates
Solution Approach 1:
The patent enables self-service operation by using the building's existing air flow generator (HVAC system) as the test equipment, eliminating the need for external blower door equipment and complex setup procedures, allowing building operators to perform their own airtightness measurements
Solution Approach 2:
The patent creates a universal measurement system that can be applied to any building with an existing air flow generator and differential pressure measurement capability, making the testing method adaptable to various building types and locations without requiring specialized equipment
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
This approach significantly reduces testing time and cost, enabling quick and accurate airtightness evaluation, capable of estimating leakage flow rates and compliance with standardized tests like 'qv10', while being flexible and adaptable to various building types.
Implementation Method 1
providing a differential pressure transducer configured to measure a relative building pressure between a building pressure at the inside of the building envelope, and a reference pressure of a pressure container that is coupled to the differential pressure transducer
Implementation Method 2
providing an air flow generator in a duct, i.e. any opening through the building envelope, wherein the air flow generator is switchable between at least two different flow rates. The method further comprises repeatedly switching the air flow generator between a first flow rate and a second flow rate for modulating the building pressure
Data Source
AI summary
A method and system for testing airtightness of a building envelope (10). An air flow generator (21) is provided that is switchable between at least two different flow rates (Q0,Q1). The air flow generator (21) is repeatedly switched between a first flow rate (Q0) and a second flow rate (Q1) for modulating the building pressure (P1) as a function of time (t) between respective equilibrium pressure values at the first flow rate (Q0) and the second flow rate (Q1). The relative building pressure (ΔP) is measured by a differential pressure transducer (31) and recorded as a function of time (t). A pressure modulation amplitude (ΔPmodulation) is calculated for providing a measure of the airtightness.