Tunnelplan Clip for acoustic cover heat pump

Tunnelplan Clip for a heat pump cover.

The outdoor unit of the heat pump can be covert with an attractive wooden casing. It would be nice if a noise reduction could also be achieved with this. However, this requires a sound-damping material whit out interruption of the airflow. The 20 mm acoustic panels are cut into strips of 475 x 50 mm and 500 x 50 mm and fastened with a clip. The clips are printed from PLA with a thickness of 6 mm. Each strip has 3 clips.

The heat pump has an outlet diameter of 500 mm (1960 cm^2). The wooden casing with applied strips has an outflow of 2 x 14 x 475 x 20 mm (2660 cm^2) plus 36%, so more than sufficient. The inflow sides with applied strips 2 x 14 x 500 x 20 mm (2800 cm^2).

What is the result
To measure this, a sound box has been placed against the wall on an elevation. The sound of a heat pump is played on this with 50 dB (+/-2) measured at a distance of 3 meters. The casing is then placed and measured again at a distance of 3 meters.
Result was 45 dB (+/-2).

An acoustic plate of 40 mm thickness will be installed at the top, back and bottom. At the front of the heat pump (without diameter 500 mm) a plate that prevents the outflowing air from flowing directly inside the cover to the inflow side
Measured at Daikin 32 dB (night mode14-01-2022)

https://www.evolarshop.com/nl/evolar-evo-cover-wood-medium-airco-buitenunit-omka.html
https://www.akoestiekwinkel.nl/akotherm-basic-d40-absorptieplaten