Innovative fibreless HVAC duct silencer based on microperforated elements

A novel environmentally friendly silencer concept for noise control in HVAC applications is presented and its acoustic properties are studied in this paper. As a sustainable alternative to the mass-produced, nowadays unfavourable fibrous material filled silencers, the silencing effect of the new solution is based on multi-layered microperforated elements. A prototype silencer following standard HVAC dimensions has been composed and optimal design and technological aspects of the fibreless solution are described. The paper also provides overview of experimental methods for the determination of primary acoustic characteristics, including low frequency transmission loss spectra in various mean flow conditions and insertion loss results for the silencer. The acoustic effect is hereby validated by comparison of the results with experimentally obtained characteristics of typical fibrous material filled units commercially available in the region. The conclusions of the acoustic study demonstrate the suitability of the silencer type for a variety of HVAC implementations were reliable and eco-friendly noise cancellation is important.