Pulse Pressurization for Low-Pressure Air Leakage Measurement
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Solution Overview
Problem
Current methods for determining air leakage in buildings, such as the blower door technique, face challenges including high pressure differences that are not representative of natural conditions, leading to inaccurate measurements and potential damage to the building structure, as well as limitations in measuring low-pressure leakage accurately due to errors from wind and buoyancy effects.
Innovation Solution
A system utilizing a processor, source of compressed air, pressure sensors, and a nozzle unit to generate a pulse of compressed air, allowing direct measurement of low-pressure air leakage by analyzing background and transient pressure signals, which minimizes the impact of wind and buoyancy and provides a more accurate and portable method for assessing air tightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high pressure difference (50 Pa) is used for measurement, then measurement reliability is improved by overcoming wind and buoyancy effects, but measurement precision deteriorates because the pressure is not representative of natural conditions requiring extrapolation
Solution Approach 1:
The patent changes the pressure parameter from high (50 Pa) to low (4 Pa) to match natural ventilation conditions. By using a pulse pressurisation technique that generates controlled low-pressure differences, the system directly measures leakage at representative conditions without requiring extrapolation, thereby improving both reliability and precision simultaneously
Solution Approach 2:
The patent employs periodic pulse pressurisation to generate transient pressure differences. The compressor delivers periodic pulses of compressed air through a nozzle, creating controlled pressure variations that allow direct measurement of low-pressure leakage while maintaining measurement reliability through repeated measurements and statistical analysis
2Ease of operation
If blower door technique is used, then ease of operation is improved, but device complexity increases and building structure may be damaged due to high pressure
Solution Approach 1:
The patent replaces the mechanical blower door system with a pulse pressurisation system using a compressor and nozzle. This substitution eliminates the need for large fans and complex door installations, reducing device complexity while maintaining ease of operation through a simpler, more portable apparatus that applies pressure pulses rather than continuous high-pressure flow
Solution Approach 2:
The patent introduces a nozzle as an intermediary component between the compressor and the building envelope. This nozzle focuses and directs the compressed air pulses, enabling controlled low-pressure application that achieves measurement goals without the complexity and potential damage associated with direct high-pressure blower door application
3Measurement precision
If multiple points test is conducted, then measurement precision is improved, but loss of time increases due to multiple measurements at different pressure levels
Solution Approach 1:
The patent uses periodic pulse pressurisation to efficiently gather multiple data points. By delivering a series of controlled pressure pulses at the target 4 Pa level, the system obtains statistically significant measurements quickly, avoiding the time-consuming process of conducting separate tests at multiple pressure levels while maintaining high measurement precision
Solution Approach 2:
The patent changes from measuring at multiple pressure levels to maintaining a constant low pressure (4 Pa) through controlled pulse delivery. This parameter change allows direct measurement at the representative pressure level, eliminating the need for time-consuming extrapolation and multiple tests at different pressures while preserving measurement precision
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 enables precise and repeatable measurement of air leakage at low pressures, reducing uncertainties and providing a more accurate representation of building air tightness, while being safer and more convenient than traditional methods, with the ability to quickly establish leakage profiles and compare to high-pressure measurements.
Implementation Method 1
A system utilizing a processor, source of compressed air, pressure sensors, and a nozzle unit to generate a pulse of compressed air
Implementation Method 2
a pressure sensor configured to measure the pressure of air residing within the space and to provide background pressure signals to the processor
Implementation Method 3
a source pressure sensor configured to measure a transient pressure during the pulse and to provide a transient pressure signal to the processor
Implementation Method 4
the processor is configured to determine the air leakage based on changes in the background pressure signals and from the transient pressure signal
Data Source
AI summary
A system (100) and method for determining the air leakage of a space (102) in a building is disclosed. The system (100) comprises a processor (120); a source (130) of compressed air; a pressure sensor (150) configured to measure the pressure of air residing within the space (130) and to provide background pressure signals to the processor (120); a nozzle unit (140) for metering the supply of a pulse of compressed air from the source (130) and for directing the pulse into the space (102) and a source pressure sensor (132) configured to measure a transient pressure during the pulse and to provide a transient pressure signal to the processor (120), wherein the processor (120) is configured to determine the air leakage based on changes in the background pressure signals and from the transient pressure signal. This provides a more reliable and cost effective way of measuring air leakage.