Industrial Noise & Vibration Centre

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Chiller Fan Noise Control – classic low frequency problem solution

Chiller fan noise reduction

Attempts are often made to solve classic low-frequency chiller fan noise using conventional silencers and noise barriers. Despite the fact that there is zero chance that these techniques can work at low frequencies, a fortune is still wasted every year on these useless palliatives. Previous failed attempts on this chiller (48.5Hz and harmonics) were replaced with aerodynamic techniques that reduced the tones by 95% and improved the fan efficiency – all by email via forwarded video clips and photos.

The company had already tried using a barrier to mitigate the complaints to no avail. This is because barriers are almost completely ineffective at frequencies below around 200Hz (drones, hums etc). Chiller fans regularly generate low-frequency tones as the blade pass hum often falls in this range. Whilst acoustic barriers and attenuators can be used to reduce the overall dB(A) noise level, they do not touch the low-frequency tones that are very commonly the actual cause of complaints. Analysis of emailed video clips immediately confirms whether this is the case, avoiding potentially costly mistakes. In contrast, our aerodynamic fan noise reduction technology addresses the low-frequency noise problem by reducing it at source with increased fan efficiency as a common additional benefit.