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2. Acoustic evaluation
2. Acoustic evaluation
acoustic evaluation
S o un d p o wer leve l
The sound power is the sound energy per second
emitted of a noise source. The sound power level is
specifi c to the source of sound, independent of dis-
tance and direction and enables an easy comparison
of diff erent sound emitting devices. The sound power
can only be determined via mathematical calculation
according to international standards of the series
ISO 3740 - based on sound pressure level measure-
ments - as well as ISO 9614, which is based on the
measurement of sound intensity. The sound power
level of the heat pumps can be found in the technical
specifi cations.
S o un d p r ess ure le ve l
In contrast to the sound power level, the sound pres-
sure level, which is caused by a noise source can be
measured. The measured sound pressure is depen-
dent on the distance from the noise source and the
receiver location (geometrical divergence) as well as
the local conditions. As the sound pressure level is a
measure of the loudness of noise sensed by humans,
the legislation defi nes limit values, that must not be
exceeded.
S o un d -p r o pag at i on - out door
With increasing distance from a point noise source,
the sound power is distributed on an increasing area
due to spherical spreading. Therefore, the sound
pressure level is continuously decreasing with in-
creasing distance from the noise source to receiver
location. Doubling the distance leads to a reduction of
the sound pressure level of 6 dB(A). Besides the di-
stance from the installation site of the heat pump the
sound, the installation situation and local conditions
also have signifi cant impact on the resulting sound
pressure level at the relevant place of immission.
Major factors of infl uence are:
- sound attenuation by massive barriers e.g. buil-
dings,
walls or diff erent terrain.
- refl ection on acoustically hard ground e.g. glass
facade and stone surfaces
- attenuation due to sound absorbing porous sur-
faces e.g. grass, trees
- reinforcement/reduction of by wind speed/direction
6
Installation instructions AERO SLM
No is e imm is s i o n
The noise caused by an source at a certain place is
expressed as Immission, the corresponding sound
pressure level is called Immission level.The immissi-
on level at the relevant place of immission can either
be calculated with the iDM-sound calculator.
calculation of the sound pressure level shall be calc
lated by means of the following examples for typical
installation situations of the outdoor unit.
Version 1: Spherical spreading into 1/2 space (free
standing installation)
Version 2: Spherical spreading into 1/4 space
(installation next to facade)
Version 3: Spherical spreading into 1/8 space:
Source: bwp-Leitfaden-Schall
Source: bwp-Leitfaden-Schall
Source: bwp-Leitfaden-Schall
(C) IDM ENERGIESYSTEME GMBH
The
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