Data centres (or "data centers" in the US) require a lot of cooling - which involves noisy chiller fans, air handling units (AHUs), cooling towers and condensers. Moreover, in addition to the general fan air noise, there are often low-frequency tonal elements (hums or drones) that cannot be silenced using conventional attenuators and acoustic enclosures and barriers. Unfortunately, poor diagnosis of the exact causes of noise complaints has often led to ineffective control of the noise from data centers that not only fail to solve the problem, but also compromise cooling efficiency.
Fortunately, there are effective low-cost alternatives that can actually increase cooling capacity...
Data centre noise problems - low-cost precision attenuation
A Noise Abatement Notice had been issued re the AHU noise from a large array of chillers at this data centre. The company had already spent nearly £100k on noise control with very little success and was considering claiming Best Practicable means (BPM) in court when the council suggested they might like to get a second opinion from us to avoid the legal route…
We carried out a very accurate diagnosis of the precise noise elements that were the cause of the complaints. Based on this evaluation, we designed a set of precise retrofit noise reduction measures that were guaranteed to be BPM. The innovative noise control measures included:
- Air handling units: changing the geometry of the AHUs and introducing internal modifications to convert existing elements into effective acoustic attenuators cut the broadband noise by >10dB(A) with no effect on fan efficiency
- Chiller condenser fans: the noise from these units was reduced by fitting a combination of high-efficiency damping coupled with internal and fan modifications, reducing the overall noise by around 8dB(A) with no effect on performance. Improvements were also made to the existing noise barriers.
These noise mitigation measures cut the overall noise at the complainants from 48.5dB(A) down to 36.5dB(A) (as illustrated by the audio recording above and by this noise signature) without affecting the performance of the cooling systems. In addition to the reduced broadband noise, the tonal "character" of the noise was also eliminated.
The whole process took approximately 6 weeks from start to finish and completely resolved the complaint issue.
Cost savings on noise control
The overall effect was to reduce the data centre cooling system noise by 15dB at less than half the previously expected cost. If this approach had been implemented in the first place, the company would have saved over £100k, the council would have saved resources and the complainants would not have had to suffer unnecessary disturbance over a 2 year period.
More details on how to reduce environmental noise from data centers
More on chiller, condenser and heat exchanger AHU fan noise reduction.
