Supermarket cooling tower noise reduction treatment plan
Author：Trlon Views: Time:2020-11-16
1. Overview of classic cases:
A group of 3 cooling tower units are placed on the roof of a supermarket in Guangdong. The residential building is about 20 meters away from the cooling tower. When the cooling tower was put into use, it was measured that the noise in front of the residential building windows was around 65dB, which was far higher than the national emission standards for residential area noise. It is a serious hazard to the ordinary life and health of the residents. The supervisor of the supermarket attaches great importance to the noise hazard. In order to reasonably and effectively suppress the noise of the cooling tower, the supermarket invites our company (cooling tower manufacturer Kangming Energy-saving Air Conditioner) to give scientific advice on the noise of the cooling tower. Reasonable treatment method.
2. Objectives for comprehensive control of cooling tower noise reduction:
1. Realize relevant national standards and regulations
2. Consider the experience of relevant staff
Considering that the real goal of the noise reduction project is to reduce the harm to the residents, we try our best to further reduce the low-frequency noise of machinery and equipment on the basis of meeting the standards.
3. On-site noise sources:
The cooling tower specifically relies on the refrigeration cycle of the mechanical equipment exhaust system to reciprocate hot water. A pump is used to send the circulating hot water to the water distributor to spray out, and the water falls into the reservoir along the filler. The exhaust fan introduces the cold air into contact with the hot water from the drench, exchanges heat and cools the water. The noise source of the cooling tower consists of the following parts:
(1) Exhaust fan intake and exhaust noise (specific noise source);
(2) Water spray noise (specific noise source);
(3) Exhaust fan reducer and motor noise;
(4) Noise of cooling tower water pumps, pipelines and valves;
Among them, it is mainly the noise of intake and exhaust of exhaust fan operation and water splashing noise. The exhaust fan radiates noise through the air inlet and outlet and the tower. The air outlet noise is about 5-10dB(A) higher than the air inlet noise, and its frequency spectrum is characterized by a continuous spectrum dominated by low frequency, which belongs to low frequency noise. When the circulating hot water falls from the sprinkler, the sprinkling water that collides with the water in the drip tray at the bottom of the tower is a high-frequency noise. The amount of sprinkling sound is related to the height of the sprinkling water and the water flow per unit time.
4. the comprehensive management implementation plan of cooling tower noise control:
In order to ensure that the noise in front of the residential building windows meets the standard, we set a noise value of 48dB. For the low-frequency noise of cooling towers such as supermarkets, our company has formulated the following comprehensive treatment methods based on our past work experience in comprehensive management of similar projects and combined with the actual situation on the spot:
1. In the middle of the cooling tower and the residential building, and on both sides of the cooling tower, the suction and sound insulation panels are used to seal, showing a "U"-shaped barrier. The overall size of the barrier is (7+18+7)*4m.
2. The cooling tower exhaust system is oriented to the side facing away from the residential building. In order to reduce low-frequency noise more reasonably and effectively, while reducing resistance damage, a 3000mm high expansion chamber muffler is set above the exhaust fan of the cooling tower unit.
5. Noise reduction effect of cooling tower
Meet relevant national standards