Technical data

www.dimplex.de 01.2012 | Project planning manual for heat pumps for heating and domestic hot water preparation | 59
Noise emissions from heat pumps 5.2
5.2 Sound propagation of heat pumps
Different measures for sound protection should be implemented
when installing heat pumps depending on the installation loca-
tion.
Indoor installation
Like any boiler, heat pumps should be connected with isolating
fixings. The heat pump should be connected to the heating flow
and return with pressure-resistant, temperature-resistant, non-
ageing, flexible hoses to prevent vibrations being transmitted.
Most heat pumps are also equipped with a vibration-isolated
compressor base plate, which means that the compressor is in-
stalled on a separate base plate positioned on on rubber buffers
for solid-borne noise insulation. For reducing the transmission of
solid-borne noise, the heat pump should be set up on SYL 250
sylomer strips (available as accessory).
Outdoor installation
Solid-borne noise insulation is only necessary if the heat pump's
foundation is in direct contact with the building. Flexible hoses fa-
cilitate the connection of the heat pump to the heating system
and simultaneously prevent any vibrations from being transmit-
ted.
Most heat pumps for outdoor installation also have a vibration-
isolated compressor base plate. Sound propagation must also be
taken into account when installing heat pumps outdoors. Blowing
out air directly onto terraces, balconies etc. should be avoided.
Blowing air directly on to building walls should also be avoided,
as this can increase the sound pressure level. Structural obsta-
cles can reduce the sound propagation. The outlet side should
be directed towards the street where possible.
NOTE
The air flow of air-to-water heat pumps installed outdoors must not be ob-
structed at any side.
Fig. 5.4: Example of how a heat pump is integrated when installed outdoors
Vibration isolation with expansion joints
Double-sphere rubber expansion joint for isolating heat pumps
and heating systems. The expansion joints absorb vibrations and
movements caused by pumps, compressors, fittings and other
sources, reduce noise output and even out internal strain (axial
and lateral deviations) stemming from imprecisions in assembly.
Fig. 5.5: Integration of expansion joints
In order to guarantee the functionality of the expansion joints and
not shorten their working lives due to any additional stress, a
number of rules should be observed:
 Expansion joints must be installed in such a way that their
position and movement are not impeded.
 During assembly and after installation, care should be taken
not to displace the bellows or subject them to any form of tor-
sional strain.
 The bellows should be protected against any damage aris-
ing from external mechanical, thermal or chemical influ-
ences.
 The bellows convolutions must be completely free from any
contamination.
Acoustic emission of air-to-water heat pumps
installed outdoors
Fig. 5.3 on page 58 shows the four main directions of sound
propagation. The air inlet side is indicated by direction "1" and
the air outlet side by direction "3".
Directional sound pressure levels of the air-to-water heat pumps
can be determined using the tables . The values at a distance of
1 m are actual measured values. The values at a distance of 5
and 10 m are calculated on the basis of hemispherical propaga-
tion in the open air. Deviations are possible in actual use on ac-
count of sound reflection and/or sound absorption due to local
conditions.
Table 5.3: Sound propagation LA 20-24AS and LA 17PS
,QVXODWHGKHDWLQJSLSHV
)OH[LEOHKRVHFRQQHFWLRQV
+HDWLQJUHWXUQ

+HDWLQJIORZ

Type LA 20AS / LA 17PS LA 24AS / LA 28AS
Dir. 12341234
1m 52 48 54 48 56 50 58 50
5m 41 37 43 37 45 39 47 39
10m 35 31 37 31 39 33 41 33