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Aquarea air-to-water heat pumps - Planning and installation manual - 02/2022
Planning
5
A rough determination of the sound pressure level L
Aeq
at a certain location at a distance r to the
heat pump can be calculated with the following formula and based on the sound power level L
Waeq
:
L
Aeq
= L
WAeq
+ 10 × log
(
Q
)
4 × π × r²
This only requires the direction factor Q in addition, which takes into account the spatial
propagation conditions of the sound source.
Direction factor Q for different arrangements of the sound source
Sound
propagation
In half space
(1 boundary: floor)
In quarter space
(2 boundaries: floor + 1 wall)
In eighth space
(3 boundaries: floor + 2 walls)
Q =
2
4
8
Arrangement
Example
The outdoor unit WH-UX16HE8 of a T-CAP bi-bloc system has a sound power level of 67 dB(A)
and is set up such that the sound can propagate in the quarter space (Q = 4). The sound pressure
level at 10 m distance is then:
L
Aeq
(10 m) = 67 dB (A) + 10 × log
(
4
)
= 42 dB (A)
4 × π × 10²
At a distance of 20 m, the sound pressure level is however still only:
L
Aeq
(20 m) = 67 dB (A) + 10 × log
(
4
)
= 36 dB (A)
4 × π × 20²
The sound pressure level can roughly be calculated even more easily by using the table below, by
subtracting the table value from the device-specific sound power level (→
, →
4.6.3.3 Technical Data (mono-bloc systems), p. 55
).
Table for rough determination of the sound pressure level based on the sound power level
Distance from the sound source (m)
Guide factor Q
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