How to deal with air source heat pump noise problem

Air source heat pump unit has the advantages of energy-saving, environmental protection, now began to be widely used in the field of heating.Such air to central heating equipment host has a characteristic, is the host and the circulating pump are of great power, and the resulting noise problem also nots allow to ignore.

heat pump Noise analysis

Heat pump units is also called heat pump vibration noise, heat pump vibration noise, heat pump units, the structure of the heat pump units noise, belongs to the noise on the physical properties.In general, heat pump noise is heat pump units produce irregular when the job is running, intermittent, continuous random noise.The noise level from 70 to 90 db (A).Upper part of the heat pump units of the noise sources include: heat pump axial flow fan;A compressor at the bottom of the heat pump;And its matching pumps.

According to the different way of noise propagation, we usually adopt the mode of vibration isolation, sound insulation, muffler, etc to deal with the noise of the heat pump units.The characteristics of heat pump units belong to the low frequency noise, low frequency noise is a longer slow attenuation, sound waves, strong penetrating power (the diffraction wave can easily bypass obstructions), so the low-frequency noise is not easy to handle.

From the structural analysis of heat pump, noise source is the compressor and fan.Run the compressor and fan noise, and the equipment running led to the steel structure of micro vibration and structure of the heat pump vibration noise, but the former is the main noise.

(1)the measured noise levels and vendors of large heat pump noise index or marked on the sample of noise level has certain difference, the measured noise is more than 3 ~ 10 db.The general heat pump A levels for 79 ~ 82 db noise, some of the heat pump more than 90 db.If in the vicinity of a residential building or on the top of the building installation for heat pump, heat pump noise is bound to cause bigger effect on the surrounding environment.

（2）Large heat pump noise is open, the noise from the both sides of the heat pump and top outward radiation, the area of the radiated noise is larger.Such as the top of the fan stations is more, there are nearly a century, a total area of up to more than 12 ㎡, on both sides of the area has more than a dozen square meters, the noise from such a large area spread (back to spread the sound source), influence scope is big, slow attenuation, within the scope of the heat pump on both sides of the 3 m noise attenuation, basically no distance attenuation within the length of the heat pump for 3 db.

（3）Frequency characteristic shows neutral generally low frequency noise characteristics of heat pump, the main noise frequency is 63 ~ 500 hz, the distance of the low-frequency noise attenuation slow, influence range, it is not easy to eliminate.

（4）Due to the bottom of the general heat pump often do not have a fully enclosed chassis, only the steel structure framework, compressor are supported on the frame, so the noise is spread down from the bottom.If the pump is installed on the roof, down the noise of the transmission is blocked by slab form reflex, install the if the cracks or holes in the structure of the plane, the noise will spread out from the crevices or holes.

Heat pump noise control measures

Concrete pump set of acoustic noise reduction to do?Pumps generally located in the roof of the building, it produces the noise are mainly the following several aspects: sound operation of the air pump set of motor, pump group compressor vibration cause the vibration of the building foundation and pump group work to encourage pipeline resonance.So thoroughly solve the problem of heat pump noise from the sound, the equipment vibration and air piping vibration in three aspects.

1、Air acoustic processing sound acoustic noise is relatively easy to governance in the pump group, group pump air acoustic noise generally not more than 85 db (A), indoor and pump group and owner at least one interval of the floor.General 120 mm of cast-in-situ concrete air sound insulation quantity is greater than 52 db, the sound isolation pumps air is quite good.But now the state of indoor sound environment has the strict request, so if the pumps with the landlord separated by a distance of the floor, the need for sound insulation with special processing, the commonly used method by sound insulation cover, soundproofing suspended ceiling, indoor sound absorption and so on.

2、Vibration isolation is generally selected pump set of system vibration isolation system vibration isolator, if the pump set is stronger vibration, optimizing the practice of building ground, because the building ground vibration effect is better, vibration and can play in the band is wider.

3、Pipeline vibration isolation handle connected to the pump group increase (change) rubber soft connection pipe, general soft connection length is shorter, less elastic, vibration isolation effect is not ideal, the overall replacement after the vibration isolation effect will increase obviously.Soft even the appropriate answer to choose better performance of vibration isolation, length is longer than the professional vibration isolation and corrosion resistance of the products.

4、Pipe supports for vibration reduction of dealing with the general pipe support and ground connection are hard links, lead to the vibration of the pipeline to the building structure, good vibration damping processing under the bracket, can prevent the spread of vibration energy to building structure.

5、Pipe wall processing pipe connected to the wall is hard commonly, a handful of pipeline vibration energy passed to the building structure, so want to release the pipe and wall body, to prevent the transfer of energy.

6、Pipe sound insulation bandaging pipeline damping vibration noise is higher, the vibration of air will also affect residents, so comprehensive damping pipe sound insulation bandaging, on the one hand, reduce the vibration of the pipeline, on the other hand can also play the role of sound isolation air.

Visible, noise control pump group is a professional and systematic project, should from the voice of the sound source, transmission and user receiver jointly do vibration acoustic design and processing, to decreasing heat pump units as noise on the impact of owner.