Technical data

58 | Project planning manual for heat pumps for heating and domestic hot water preparation | 01.2012 www.dimplex.de
5.1.2 Noise emissions from heat pumps
5.1.2 Sound propagation
As already described, the sound power spreads out upon an in-
creasing surface with increasing distance, so that the resulting
sound pressure level decreases at an ever-increasing distance.
Additionally, the sound pressure value depends upon a specified
point of the sound propagation.
The following characteristics of the environment influence the
sound propagation:
 Shading due to major obstacles, such as buildings, walls or
land formations
 Reflections on reverberant surfaces such as rendering and
glass facades of buildings, or the asphalt and stone surfaces
of floors.
 Reduction of the level propagation by sound-absorbing sur-
faces, such as fresh snow, bark mulch or similar.
 Increase or reduction due to air humidity and air temperature
or wind direction
Fig. 5.2: Sound pressure level reduction with different installation
There are three different versions of heat pump installation:
 Free-standing heat pump installation (Q=2)
 Heat pump or air inlet/outlet (for indoor installation) on a
building wall (Q=4)
 Heat pump or air inlet/outlet (for indoor installation) on a
building wall with edge pointing inwards (Q=8)
For each of these installation versions, there is a different sound
pressure level inspection the further away you get from the heat
pump.
Example:
Sound power level LA 9TU: 60 dB(A)
Fig. 6.2 shows the sound pressure level inspection for the three
different installation version with a LA 9TU.
NOTE
Directional sound pressure levels are significant for heat pumps installed
outdoors.
For air-to-water heat pumps installed outdoors, there are four
main directions of sound propagation. The air intake side is indi-
cated by "1" and the air outlet side by "3".
Fig. 5.3: Sound directions for air-to-water heat pumps installed outdoors.
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