Noise isolation in building HVAC system using recyclable plastic bottles

Abstract

The paper proposes an improvement of the acoustic environment in a sustainable building by utilizing differently sized discarded bottles. The HVAC (heating, ventilation and air conditioning) ducts in buildings serve as conduits for purified air, but they also generate noise as a result of turbulent flow caused by internal irregularities within the ducts. This study involves the modification in the design of ducts by utilizing the discarded or recyclable bottles. By incorporating recyclable bottles along the periphery of the duct, there is decrease in the generation of flow noise. The work presents a comprehensive investigation that employs numerical, experimental, and theoretical methods to assess the sound transmission loss (STL) within the redesigned air duct. The four-microphone impedance tube technique is utilized to measure the STL. The findings reveal that connecting bottles along the length of the air duct at specific intervals leads to a significant reduction in low-frequency noise. Additionally, increasing the number of bottles arranged radially along the air duct leads to a further enhancement and widening of the bandwidth of sound transmission loss (STL).