From the structure analysis of the heat pump, the noise source is the compressor and exhaust fan. Compressor and exhaust fan operation noise, and due to the operation of the equipment leads to the steel structure of the heat pump micro-vibration and structural vibration noise, but the former is the main noise.
First, the measured noise level of large heat pumps and sellers to provide noise indicators or samples marked on the noise level there is a certain difference between the measured noise are beyond 3 ~ 10dB. general heat pump A sound level noise is 79 ~ 82dB, some heat pumps more than 90dB. if installed near the residential building or office building on the roof of a number of heat pumps, the noise will inevitably be caused by the surrounding environment The larger the impact.
Secondly, the noise of large heat pumps is open, the noise is mainly radiated from the sides and top of the heat pump, and the area of radiated noise is large. Such as the top of the exhaust fan more, more than nearly a hundred units, the total area of up to 12m2 or more, the area on both sides of the dozen square meters or so, the noise from such a large area to spread out (echoes source propagation), a large range of influence, slow decay, in the heat pump on both sides of the 3m range of the noise basically no attenuation in the length of the heat pump within the distance of the attenuation rate of 3dB.
Thirdly, the noise of heat pumps Frequency characteristics are generally neutral low-frequency characteristics, in which the main noise frequency is 63~500Hz, low-frequency noise distance attenuation is slow, the influence of a wide range, not easy to eliminate.
Fourth, because the bottom of the general heat pump often does not have a fully enclosed chassis, only the steel frame, the compressor are supported on the frame, so the noise is also propagated from the bottom downwards. If the heat pump is installed on the roof, the downward propagation of noise is blocked by the floor to form a reflection, if it is installed in the structural plane with gaps or holes, the noise will spread out from the gaps or holes.