Where Does the Cooling Tower Noise Come from? How to Control It?

Cooling towers are not only widely used in petrochemical, chemical, power, metallurgy and other industrial enterprises, but also used in the water circulating systems of urban hotels, restaurants, shopping malls and office buildings. These facilities generate a lot of noise during operation and this will cause negative impact on the daily life of the surrounding residents. How to achieve effective cooling tower noise control?

First, we need to find out where the cooling tower noise mainly comes from.

• Fan air intake and exhaust noise;
• Water spraying noise;
• Fan reducer and motor noises;
• Cooling tower water pump, piping and valve noise;

Among these noises, fan air intake and exhaust noise and water spraying noise are the main noise. The fan radiates noise through air inlet and outlet and the tower body. The outlet noise is about 5-10 dB (A) higher than inlet noise. As the noise spectrum features low-frequency-based continuous spectrum, therefore, it is a low-frequency noise. When the circulating hot water falls off from the water spray device, it collides with the water in the water tank at the bottom of the tower and produces water spraying noise. This noise is a high-frequency noise. The size of the water spraying noise is related to the falling height and the water flow per unit time. The overall noise of the cooling tower is low-frequency-based continuous spectrum without prominent noise peak value. It generally falls between 31.5-2000 Hz and the noise level is about 55-85 dB (A).

The cooling tower noise is low frequency and its direct harm is not so obvious as high frequency noise, however, people who living in this noise environment for a long period are prone to increase blood pressure, rapid heartbeat, irritability, neurasthenia and other symptoms, seriously affecting people's physical and mental health.

Then, we need take corresponding noise control measures.

• In terms of reducing cooling tower inlet and outlet noise, we may use noise eliminators, noise barriers and other noise reduction devices.
• When it comes to reduce water spraying noise, we may choose acoustic booths, noise barriers and other noise reduction equipment.
• In the case of reducing water collection tank waterfall noise, we may use muffler pad, waterfall noise reduction mats and other noise reduction devices.
• As for reducing cooling tower vibration, we may use shock absorbers, rubber flexible connection and other vibration reduction devices.

When governing cooling tower noise, we shall fully consider the causes and characteristics of cooling tower noise and take corresponding measures. Under the premise of ensuring the required technical data, we need to upgrade the cooling tower equipment and tackle the noise issues from the source.