How do I take noise reduction measures for air source heat pump units?

In daily life, while creating a comfortable living environment, air source heat pump units also bring serious environmental noise problems. Among residents' complaints about environmental pollution, the noise problem has been "outrageous" and accounted for most of the proportion. How to reduce the noise of air source heat pump units has become an urgent problem in this industry.

For the air source heat pump system, there are four main sources of noise: ① the noise of the host computer; ② the flow noise of the pipeline liquid; ③ the noise of the water pump; ④ the noise of the fan coil. In addition, there is a comprehensive operation analysis and processing of the system.

The solution is mainly through muffling, isolating, damping the equipment and choosing a reasonable operating mode, so that the noise around the building and the room used can meet the requirements of the code. After finding the root of the problem, it is relatively easy to solve it.

1.Air source heat pump host noise reduction

Air source heat pump unit noise mainly includes aerodynamic noise, mechanical noise and pipe noise. When placing it on the top floor of the building, it’s best to suggest that Party A should design the relevant parameters by the design institute, and we will install it according to the design requirements, but in the actual process, we may need to design more.

According to the weight of the air source heat pump, select the channel steel or I-beam, try to choose a corner of the building, weld the steel platform on site, and place the support point of the platform on the column of the building. For general engineering, buildings + 5CM rubber damping pads + section steel platform + 5CM rubber damping pads + air source heat pump equipment can meet the vibration damping requirements. However, for high-demand places, a more effective method of damping can be used, that is, building + 5CM rubber damping pad + steel platform + spring damper + air source heat pump equipment.

2.Air source heat pump pipe noise reduction

Let me talk about the noise removal method of the pipeline liquid flow noise.

First of all, pay attention to the choice of hanger. For pipeline installation, the national standards must be strictly followed. The main pipe hanger should use spring vibration damping hanger. The hanger should not be fixed on the floor. It should be fixed on the beam as much as possible. Channel steel beams can also be erected between the beam and the beam. . The water pipe must be used for passing through the floor or wall, and the space between the pipe and the pipe must be filled with non-combustible materials.

Secondly, the choice of the insulation layer of the pipeline is also very important. The insulation layer of the pipeline not only plays a role in insulation, but also plays a role in reducing and eliminating noise.

Of course, the liquid flowing in the pipe will also produce a certain amount of noise. Therefore, the flow rate of the pipeline is closely related to the size of the pipe diameter. For example: DN20, the flow rate is between 0.4M/S and 0.6M/S, and DN50 is about 1M/S. Since there are detailed information available, I will not list them all. In general, the flow rate control within 1.5M/S basically meets the requirements.

3.Pump noise reduction

Pump noise is mainly composed of mechanical noise and aerodynamic noise, the latter is relatively more. According to the characteristics of noise, the noise control of water pump is mainly to control the noise of its motor and the noise produced by the inlet and outlet pipes.

1) First of all, the water pump should be a high-quality water pump with high efficiency and low noise, and the hydraulic and resistance of the pipe network should be calculated more accurately during design. The actual head of the pump is 1.1 times the design head to meet the requirements. The pump with too large head is not only noisy, but also consumes high energy.

2) When the water pump is installed, the appropriate transmission rate should be selected for the vibration isolation calculation, so that the frequency ratio of the vibration isolation system and the pump speed is greater than 3. This problem is a bit too professional for the construction personnel. The simple method is to use a vibration reduction platform to reduce vibration and noise. The weight of the platform should be 1.5 to 2.5 times the weight of the pump. The platform form is preferably steel-concrete structure, which is characterized by small size, sturdiness and durability, and can be standardized and designed and produced. The inlet and outlet pipes of the water pump must be connected with matching soft joints. Spring damping hanger.

3) If some users have high requirements for noise, a sound insulation cover can be used to seal the pump equipment to isolate it from the external environment. It is particularly worth noting that the sound insulation cover must ensure that the heat generated during the operation of the pump and the heat energy converted from the noise in the cover must be diffused to the external environment in time to ensure that the temperature rise of the pump is within the allowable range, and at the same time, it must be convenient for maintenance.

The most effective sound insulation cover is determined by the material with high sound conduction attenuation rate and the structure type that facilitates ventilation and heat dissipation. The material can be steel plate or aluminum plate. Steel plate has better sound insulation effect than aluminum plate of the same thickness, but aluminum plate is lighter and easy to move and repair, so the material should be selected according to the actual situation. At the same time, in order to improve the sound absorption capacity and reduce the sound radiation of the board surface, a certain thickness of asphalt asbestos damping paint can be applied to the surface of the board.

4.Fan coil noise reduction

Because the noise of the fan varies with its type and specifications, and varies with its working conditions, it is necessary to determine the noise reduction plan according to the specific situation. When selecting the air plate, try to choose a fan coil with low noise and high efficiency. The pipes at the inlet and outlet of the air plate should not be turned sharply, and flexible joints should be used and maintained. The length of the joint is generally 100-150mm, and the material is fire-resistant glass cloth or fire-resistant artificial leather, and the air pipe behind the short pipe is wrapped with ultra-fine glass wool of 50 mm thick and 1 to 2 m long. This will have a good noise reduction effect.

5.Operating mode noise reduction

In many cases, designing a reasonable running time for the air source heat pump system is also a good way to reduce noise. Such examples are too numerous to mention, such as hotels, workshops, office buildings, etc. are more applicable. Advocating that the system must be designed with a reasonable water tank, there are also factors in this regard. For example, for hotels, the host can be set to run late at night, in the morning or afternoon, and store energy (cold or heat) in the water tank, which can greatly improve the noise environment.

To give another example, such as an office building or a car 4S shop, employees are off work at night, and the low price is used for cold storage. Not only the electricity price is low, but the energy efficiency ratio is high. When the system works during the day, the air source heat pump does not need to be activated because of energy storage. , So the biggest noise source does not exist.

To sum up, noise reduction is a systematic project. It needs to be inseparable from the specific requirements of the customer on the air source heat pump site, the installation and operation mode of the air source heat pump equipment, but as long as the essence of things is grasped, any problem will be solved.