Title: Noise reduction enabling natural ventilation technologies
Speaker: Prof. Du Liangfen
Time: April 28, 9:30
Venue: 213, Building 18, School of Physics and Optoelectronics
[Abstract]
The rapid pace of urbanization and the steady growth of population have intensified the issue of traffic noise, particularly in densely populated cities such as Hong Kong, Singapore, and Guangzhou. For residents grappling with disruptive effects of traffic noise, the immediate solution often involves closing windows or doors that face busy roads. However, this remedy simultaneously obstructs natural ventilation. In the post-COVID-19 era, there is a growing recognition of the profound significance of natural ventilation, as it offers a multitude of advantages, including the improvement of indoor air quality, the mitigation of health-related risks, and the advancement of sustainable green building practices. In an effort to address the dual challenge of noise reduction and natural ventilation, we have introduced three innovative technologies that enable both: acoustic friendly ventilation window (AFVW), ventilated acoustic meta-barrier (VAMB) and ultracompact double layered acoustic grating (UDLAG). 1) The AFVW consists of a double layer of glass panes with two staggered openings and a mechanical ventilation system integrated between the two glass panes. Two prototype windows have been installed in the NUS (National University of Singapore) – CDL (City Developments Limited) smart green home and CDL’s premises for test-bedding and system refinements. Field measurement results have demonstrated that the AFVW achieves a noise reduction level 13dB higher than that of a conventional window with the same opening size, all while providing approximately five times the air changes per hour compared to the conventional window. 2) The VAMB is comprised of layered Helmholtz Resonators (HRs) integrated with a ventilation duct. Thanks to local resonance, this design delivers extraordinary noise reduction performance across a broad frequency band, covering the various resonant frequencies of the HRs. 3) The UDLAG consists of a double layer of rigid panels with multiple perforated slits. Different from its noise-mitigating counterparts, the UDLAG is specifically designed to deflect noise away from sensitive areas. By optimizing the positions of the slits on both layers, it can effectively concentrate the energy of an incident acoustic wave within a predefined focusing region in an arbitrary direction. This presentation will provide an in-depth discussion on these three innovative technologies, spanning from the initial prototype design and fabrication stages to comprehensive evaluations of their noise reduction and natural ventilation capabilities.
Announced by the School of Physics and Optoelectronics
