Initial position
An OCHSNER heat pump from the "AIR-85-C14A" model series was used as part of a renovation project. The outdoor unit is designed as a table evaporator. The system has the following dimensions: 2,225 x 1,940 x 1,340 mm L x W x H. The system has 2 axial fans with a maximum volume flow at full load of 20,000 m3/h.

The heat pump is located outside of a kindergarten in Stuttgart.
 
Acoustic enclosure concept 
The basic structure of the acoustic hood is an aluminum plug-in profile frame, the service doors around the system are integrated into this profile frame. The service doors are based on aluminum panels with a thickness of 1.5 mm with internal 40 mm thick insulation made of Stratocell® Whisper, the material has one of the best sound-absorbing properties available on the market.
 
The acoustic hoods have the following dimensions: 2,800 x 2,500 x 1,700 mm (L x W x H) with a weight of 375 kg.
The air openings and the free air inlet openings are designed with around 15% above the required air volume of the system. The air flow is offset to the sides, so that no air short circuit can occur between the exhaust air and supply air. With the air deflection by 90°, the airborne sound is broken, which leads to a significant reduction in the exit noise. The air outlet speed is around 1.98 m/sec.

Noise reduction
The all-round noise reduction across the frequency spectrum from 63 to 8,000 Hz is between 19 and 20 dB(A), with a pressure loss of around 20 Pa.
 
Adaptation to the environment
The acoustic hood was made entirely of aluminum and powder-coated in the RAL color: 5022 (night blue).

Additional Information
info@silent-mode.com
​www.silent-mode.com (German)
www.silent-mode.net (English)
www.silent-mode.it (Italian)

​Large heat pumps are particularly suitable for use in industry, in municipal infrastructure or in large residential, commercial and commercial buildings. While heat pumps for use in private residential and commercial buildings are now standard heating technology and the use of condensing technology is increasingly being pushed back, there is still great potential in the broad application of large heat pumps and industrial heat pumps in the power range from 200 kW to > 1,000 kW.

But their areas of application already show the way that the mostly with multi-stage compressors and high air volume, meet the quiet needs of the residents in the dense construction in cities.

Our modular sound hoods can help here, by combining several modules, practically all mooring sizes can be equipped with a sound hood.

The picture shows a sound hood for a heat pump with a heating capacity of 120kW and a cooling capacity of 315kW installed in our warehouse before shipping.

The system has 5 axial fans with an air volume at full load operation of 85,000 m3/h. The dimensions of the system are 3,600 x 2,250 x 2,320 mm (L x W x H).

The acoustic hood has the following dimensions: 5,000 x 3,300 x 3,100 mm (L x W x H). The acoustic hood is designed for an air flow rate of 92,000 m3/h and brings a noise reduction of 18 - 20 dB(A) at a distance of 1 meter, measured according to the enveloping surface method.