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Aquarea air / water heat pump – design handbook 07 / 2014
Project Design
Acoustics
Example
Example
The outdoor unit WH-UD12FE5 of a bi-bloc system has a sound power
level of 67 dB(A) and is installed such that the sound can propagate into
the quarter space (Q = 4). The sound pressure level as 10 m distance
results in:
L
Aeq
(10 m) = 67 dB (A) + 10 × log
4
= 42 dB (A)
4 × π × 10²
(
)
For a distance of 20 m the sound pressure level is still:
L
Aeq
(20 m) = 67 dB (A) + 10 × log
4
= 36 dB (A)
4 × π × 20²
(
)
The sound pressure level can be determined roughly from the following
table, in that the table value is subtracted from the unit specific sound
power level (see technical data).
Directivity
factor Q
Distance from the sound source in m
1
2
4
5
6
8
10
12
15
2
-8 -14 -20
-22 -23,5 -26
-28 -29,5 -31,5
4
-5 -11 -17
-19 -20,5 -23
-25 -26,5 -28,5
8
-2
-8 -14
-16 -17,5 -20
-22 -23,5 -25,5
Table for rough calculation of the sound pressure level based on the sound power level.
Note
Through the selection of the installation location, the sound pressure
level can be increased or decreased. Installation on reflective floor sur-
faces should be avoided. Sound pressure level can be reduced further
by constructing obstructions, whereby the air flow itself should not be
obstructed.
The sound output direction of outdoor and / or monobloc units should
be selected if possible towards the street, since neighbouring rooms to
be protected are seldom oriented in this direction.
In case of doubt, an acoustic engineer must be consulted.
