Whether in an industrial, commercial or civil application, manufacturers of cooling towers today increasingly have to monitor noise emission levels. Cooling towers are mechanical equipment and, as such, may represent a more or less significant source of noise pollution.
Designed to work intermittently throughout the year (especially in industrial applications), this equipment must comply with the noise levels dictated by the building regulations of the place where they are installed and the defined design requirements. Cooling tower manufacturers are therefore obliged to build this equipment following these specifications, sometimes using additional and targeted silencing solutions.
This is true, for example, with cooling towers for air conditioning in hospitals or near residential areas, where noise reduction is imperative.
There are essentially three primary sources of noise from an evaporative cooling tower:
There are several solutions to control and thus reduce noise pollution caused by cooling towers and evaporative condensers, depending on the type of equipment and the cause of the noise generated. As an example, we present a list of possible solutions:
Regarding the reduction of noise generated by fans, a premise is in order. Axial fans, while being the best choice in terms of energy efficiency, are at the same time the least effective choice in terms of noise. Centrifugal fans, by contrast, are less effective in terms of energy performance but offer more solutions in terms of noise reduction, thus ensuring quieter operation.
That said, to attenuate broadband fan noise, cooling tower manufacturers often provide silencers (effective in the case of medium to high frequencies). Decsa, too, offers factory-designed and tested sound-absorbing inlet and discharge silencers that can effectively attenuate fan noise.
Alternatively, the recommended solution in case of high frequency and noise from one direction only, noise barriers can be used. The main problem with barriers in the context of cooling towers is that they are only effective when close to the source. This in turn results in reduced airflow, reducing system efficiency and increasing operating costs.
It should be pointed out that the above-mentioned silencers and sound barriers do not attenuate low-frequency sound.
The noise caused by the water falling into the water collection tank, although perceptible especially close to the evaporative cooling tower, is nevertheless a medium-high frequency sound that can be a significant source of the noise.
For forced-draft cooling towers, where fans push air into the equipment, the noise is reduced as the water collection tank is inside the tower and is fully enclosed.
In the case of induced-draft cooling towers, especially those with suction fans positioned at the top of the tower, the tank is exposed to the open, making the noise much more perceptible (the greater the size of the equipment). Today there are indeed systems that, positioned close to the tank, reduce the perceived noise of falling water (anti-splash systems).
Decsa also offers this kind of solution.
Decsa has a wide range of the latest generation of centrifugal and axial fan cooling towers, designed to ensure minimum noise and maximum performance, and suitable for all applications in the process cooling, HVAC and industrial refrigeration industries in the most diverse plant configurations. Soundproofing systems are also available as accessories upon request.
Contact your local representative to find out more about our quieter solutions.
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