Development of a full scale metamaterial window with optimised ventilation and noise-reduction performance

Noise reduction is a key factor regarding indoor comfort and energy-smart Architecture and Engineering. In most cases, occupants of the building must choose between a naturally ventilated indoor environment or a quiet one. On the other side, acoustic metamaterials (AMMs) have recently found interesting applications in ventilation ducts by conjugating innovation and sustainability. Previous research conducted by the author has proved AMM-based windows to be a resourceful way to address both natural ventilation and reduce the incoming noise propagation ergonomically (i.e. with design which is optimised for the use of the final user); however, the effective spectral range lacked in the lower frequencies (50-350 Hz). This study aims, therefore to implement the previous model with an ergonomic full-scale acoustic metawindow (AMW). The metamaterial system is enhanced by doubling the original resonating volume and coupling it with a ¾ wavelength resonator. According to the parametric numerical FEM analysis (already assessed in previous experiments) over the opening ratio of the AMW (going from 3 to 33%) the TL related to the window is improved overall by 70% on the frequency range from 50 to 350 Hz. Such results encourage the use of new AMMs ergonomic windows in place of standard ones to achieve both natural ventilation and noise attenuation in the hearing main spectrum, being resourceful for domestic, sanitary, and public applications. This work is part of the author’s PhD thesis led between Sheffield University (UK) and the A*STAR – Institute of High Performance Computing (SG), which reports a multidisciplinary methodology to implement acoustic metamaterial (AMM) technology in window design to allow noise insulation and natural ventilation simultaneously. The PhD thesis includes results from Social and Natural Sciences, Ergonomic, Numerical, Analytical and Experimental investigations to draw a full-scale window prototype using AMMs. The so-called acoustic metawindow (AMW) allows TL of 10-60dB on a significant frequency range for human hearing (50-5000 Hz) in an open configuration while allowing sufficient natural ventilation. In addition, the AMW is proven to positively impact the indoor environment from both physical and human perception points of view, thanks to its ergonomic and psychoacoustic nature. This PhD project has opened a new AMMs field of investigation that is not limited to noise reduction but also includes outdoor acoustic stimuli optimisation towards a more comprehensive indoor comfort.

Keywords: ; Acoustic metamaterials, Ergonomics, Natural ventilation, Sound Insulation, Psychoacoustics

• 2025 10th International Conference on Energy Efficiency and Agricultural Engineering (EE&AE) Radka Atanasova, Martin Ivanov, Ivan Dimchev, pp.1 (DOI:10.1109/EEAE65901.2025.11273777)

Gioia Fusaro, Sviluppo di una finestra metamateriale con ventilazione e attenuazione acustica ottimizzata in "RIVISTA ITALIANA DI ACUSTICA" 2/2023, pp 9-16, DOI: 10.3280/ria2-2023oa15499