Air vent shape optimization with metamaterials.

Heating, Ventilation and Air Conditioning (HVAC), are crucial in every building for the well being of the occupants. While these equipments take care of the air quality with exhausting polluted air out and bringing fresh air in, they can let a polluant in: noise. Noise can have non-physical effects like disturbed sleep, cognitive problems or even influences on heart diseases. Recent developments in the acoustic field shown the use of metamaterials that can reduce noise while keeping good ventilation. The sonic crystals, disposed in a certain pattern following the Bragg's law, can be tuned to reduce noise on a wide frequency band. The design of an air vent, known as a metacage, was made by using open source numerical simulations. Based on a numerical plan and optimization methods, this study's goal was to find the optimal solution for the HVAC to reduce noise while minimizing ventilation loss. Following the simulations results, the metacage generated was 3D printed for validation in the laboratory, showing the corroboration with the simulations. The final results show third-octave bands with a TL peak over 10dB and an average of 3dB for all the others bands up to 10kHz. All this while keeping minimal ventilation loss.