Detection of Air Leakage in Building Envelopes using Microphone Arrays

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Unintended airflow through building envelopes leads to an increased demand in heating and cooling energy. The most common way to measure air leakage of buildings is the blower door test, which quantifies the overall leakage rate of one room or a building. To reduce air leakage and associated energy loss  in new and existing buildings, it is
necessary to identify leak locations and prioritize sealing of more substantial leaks. However, detection and quantification of individual leaks with smoke tracers or infrared thermography are challenging, time-consuming, and depend on the operator’s experience.
Acoustic methods have been identified to have the potential to localize and quantify individual leaks without the need for pressure or temperature differences. In this work, the acoustic beamforming method is proposed using a microphone array to detect leak locations and visualize them (acoustic camera). The objective of this investigation is to identify the potential of this technique for application to building envelopes. A pair of omnidirectional speakers is placed as a sound generator inside a room, and the microphone ring array with 48 microphones outside.  As an experimental setup, cable   ties are wedged in  a window frame to  simulate a damaged window gasket and to create reproducible leaks  of different sizes at  the same place.  Overlay of an optical picture with the acoustic image obtained from beamforming enables the visualization of leaks of sound through the building  envelope. All experiments were conducted using white noise with an analyzed frequency range  of  1-25 kHz. The sound sources are evaluated at multiple third-octave bands within this frequency range, enabling a distinction between these leaks at different frequencies.

Citation: IAQ 2020: Indoor Environmental Quality

Product Details

Published:

2021

Number of Pages:

9

File Size:

1 file

Product Code(s):

D-IAQ2020-C12

Note:

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