87
Aquarea air / water heat pump – design handbook 07 / 2014
Project Design
Acoustics
Sound power level
• Interruption by obstructions like buildings, walls or landscape
formations
• Reflection from surfaces such as walls, glass facades, buildings or
asphalt-covered areas as well as areas made of stone
• Absorption of sound on e.g. grass, bark-chip mulch, leaves or
fresh-fallen snow
• Wind can increase or decrease the sound pressure level (depending
on wind direction).
An estimation of the sound pressure level L
Aeq
at a certain place with
a distance r from the heat pump can be calculated with the following
formula based on the sound power level L
WAeq
:
(
)
L
Aeq
= L
WAeq
+ 10 × log
Q
4 × π × r²
For this, one additionally needs the direction factor Q, which considers
the spatial radiation conditions of the sound source:
Sound
propagation
Half space
Quarter space
Eighth space
Q =
2
4
8
Arrangement
Directional factor Q for different arrangements of the sound source