Active noise control in an autonomous ventilation module

Abstract

Decentralised ventilation systems are becoming increasingly popular for buildings since they are more environmentally friendly than other systems. The other main ventilation system, the centralised one, was previously used for entire building's apartments. Nowadays, decentralised ventilation modules, which are distinct to each apartment, are preferred. However, they produces more bothersome noise than a decentralised system as they directly operate in the room that they ventilate. The goal of this study is therefore to cancel the noise produced by the ventilation module using Active Noise Control (ANC). This method indeed allows the sound to be continuously reduced, responding to any change of speed of the fan. The LMS and FxLMS are popular algorithms used for active noise control. A lot of research has been conducted using those algorithms and they have shown their efficiency. For that reason, they were used in this thesis. Noise reduction is estimated using only pure sinusoidal signals, corresponding to a tonal noise generated by the impeller of the fan. In the end, the proposed method of Ahmed et al. (2021) combined with a band-pass filter in the frequency range of interest showed the best sound power reduction.