Sound and vibration management
Compressor sound radiation
For sound radiating from the compressor, the
emission path is airborne and the sound waves
are travelling directly from the machine in all
directions.
The CH scroll compressors are designed to be
quiet and the frequency of the sound generated
is pushed into the higher ranges, which not only
are easier to reduce but also do not generate the
penetrating power of lower frequency sound.
Use of sound-insulation materials on the inside of
unit panels is an effective means of substantially
reducing the sound being transmitted to the
outside. Ensure that no components capable
of transmitting sound/vibration within the unit
come into direct contact with any non-insulated
parts on the walls of the unit.
Because of the unique Danfoss design of a
full-suction gas-cooled motor, compressor
body insulation across its entire operating
range is possible. Acoustic hoods are available
from Danfoss as accessories. They have been
developed to meet specific extra low noise
requirements. They incorporate sound proofing
materials and offer excellent high and low
frequency alternative.
These hoods are quick and easy to install and do
not increase the overall size of the compressors
to a great extend.
Refer to section “Running sound level” for sound
attenuation and code numbers.
Vibration isolation constitutes the primary
method for controlling structural vibration.
Danfoss CH scroll compressors are designed to
produce minimal vibration during operations.
Once the supplied rubber grommets have been
properly mounted, vibrations transmitted from
the compressor base plate to the unit are held
to a strict minimum. In addition, it is extremely
important that the frame supporting the
mounted compressor be of sufficient mass and
stiffness to help dampen any residual vibration
potentially transmitted to the. For further
information on mounting requirements, please
refer to the section on mounting assembly.
Note: For parallel assemblies see specific
recommendations in Danfoss parallel application
guidelines (Rigid mounting).
The tubing should be designed so as to both
reduce the transmission of vibrations to other
structures and withstand vibration without
incurring any damage. Tubing should also be
designed for three-dimensional flexibility. For
more information on piping design, please see
the section entitled “Essential piping design
considerations”.
Gas pulsation
Mechanical vibrations
The Danfoss CH scroll compressors have been
designed and tested to ensure that gas pulsation
has been optimised for the most commonly
encountered air conditioning pressure ratio. On
heat pump installations and other installations
where the pressure ratio lies beyond the
typical range, testing should be conducted
under all expected conditions and operating
configurations to ensure that minimum gas
pulsation is present. If an unacceptable level
is identified, a discharge muffler with the
appropriate resonant volume and mass should
be installed. This information can be obtained
from the component manufacturer.
32
FRCC.PC.026.A4.02
Application Guidelines