Attenuators for noise control in air conditioning systems: case study with the use of reused sound-absorbing materials

Abstract

The HVAC (Heating, Ventilation and Air Conditioning) machines cause noise during their operation, due to the items that compose them and the movement of the fluid along the branches that distribute the air. These noises, when intense, cause physical and mental strain on people, depending on the sound level emitted by the devices. As they are present in the daily lives of countless workers and students, strict sound control is necessary in order to reduce damage caused by sound intensity. This work aims to identify changes in acoustic attenuators used in HVAC systems for the incorporation of reused sound-absorbing materials. For this, variables that indicate the efficiency of acoustic attenuators for air conditioning systems were identified, in addition to characterizing the main forms of emission and propagation of sound in terms of sound pressure levels and spectral composition of a typical HVAC system. The sound-absorbing materials used in HVAC systems were also analyzed according to their absorption coefficient. From the analyses, it can be concluded that with the use of reused sound-absorbing materials it is possible to have absorption coefficients very close to the results of primary materials, in addition to achieving higher levels of attenuation in different frequency bands.