Reduction through Brick Wall Barrier and Acoustic Sponge of Environmental Noise Levels from Chiller Cooling System

Abstract

The aim of this study was to investigate the noise level reduction of the air cooled liquid chiller to the desired levels of environmental noise requisite. Noise control procedures are implemented with various systems to prevent environmental noise disturbances. This paper examines the application of a passive noise control approach to the control of air-cooled liquid chiller noise located in the garden of an official institution. The approach of passive noise control utilizing brick walls with acoustic sponge in the immediate vicinity of the chiller is discussed. When the chiller was covered with a brick wall, the noise level was reduced by 5.5 Leq dBA 1 m away from the nearest residence. However, this reduction could not meet the requirements of legal regulations. Therefore, the inside of brick wall was covered with acoustic sponge. As a result, the ambient noise level where 1m away from the nearest residence to the chiller has been reduced to the background noise levels with a total reduction of about 8.5 Leq dBA. It is shown that, due to the noise produced by the chiller fans and compressors, so as to achieve significantly cognizable levels of noise reduction it is necessary to isolation brick walls with acoustic sponge.