A Metawindow with Optimised Acoustic and Ventilation Performance

Abstract

Crucial factors in window performance, such as natural ventilation and noise control, are generally conceived separately, forcing users to choose one over the other. To solve this dualism, this study aimed to develop an acoustic metamaterial (AMM) ergonomic window design to allow noise control without dependence on the natural ventilation duration and vice versa. First, the finite element method (FEM) was used to investigate the noise control performance of the acoustic metawindow (AMW) unit, followed by anechoic chamber testing, which also served as the validation of the FEM models. Furthermore, FEM analysis was used to optimise the acoustic performance and assess the ventilation potential. The numerical and experimental results exhibited an overall mean sound reduction of 15 dB within a bandwidth of 380 to 5000 Hz. A good agreement between the measured and numerical results was obtained, with a mean variation of 30%. Therefore, the AMW unit optimised acoustic performance, resulting in a higher noise reduction, especially from 50 to 500 Hz. Finally, most of the AMW unit configurations are suitable for natural ventilation, and a dynamic tuned ventilation capacity can be achieved for particular ranges by adjusting the window’s ventilation opening. The proposed designs have potential applications in building acoustics and engineering where natural ventilation and noise mitigation are required to meet regulations simultaneously.

Broadband potential optimisation of a full scale acoustic metawindow performance.

“…Nevertheless, the noise reduction is guaranteed by the customisation of the AMW design (depending on H) and the degree of opening (depending on T). The numerical analysis of the acoustically optimised model of AMW (in several different customisable designs according to T and H) finally shows that with a tailored perforated AMM unit structure [8], noise attenuation can be consistently achieved within the frequency range of 50-5000…”

“…As achieved in a previous study for the AMW unit [8], acoustic optimisation is investigated for the full-scale AMW design. In Fusaro et al [8], three perforation configurations were tested numerically for the AMW unit for acoustic performance improvements in the lower frequency range.…”

“…As achieved in a previous study for the AMW unit [8], acoustic optimisation is investigated for the full-scale AMW design. In Fusaro et al [8], three perforation configurations were tested numerically for the AMW unit for acoustic performance improvements in the lower frequency range. The resonating volume extension through AMM unit cells panels perforation was investigated to reach a resonance that affects low-frequency bandwidth.…”

“…However, these systems faced some limitations in terms of passive energetic requirements, broadband frequency range of application, and ergonomic value [6,7]. With this aim, the latest research development managed to achieve ergonomic driven window design based on acoustic metamaterials [8,9], which showed potential over ventilation and noise reduction but highlighted limitations over the lower frequency range. For these reasons, it is necessary to investigate further an ideal design of AMM based windows to address noise control and natural ventilation on a wider frequency range.…”

Analysis of Impact of Natural Ventilation Strategies in Ventilation Rates and Indoor Environmental Acoustics Using Sensor Measurement Data in Educational Buildings

“…al. [ 38 , 39 ] proposed a new metacage window which allows natural ventilation and noise reduction based on the principle of Snell’s Law. The used of this novel prototype showed an overall mean sound reduction of 15 dB within a bandwidth of 380 to 5000 Hz.…”