The planning of our sound hood is based on the following principles:
1. The smallest possible size of the sound hood
2. Modular expandability
3. Highest possible sound insulation
4. Avoidance of system performance losses
5. Unhindered access for service and maintenance
6. Relocation of the air inlet to the shady side of the system
lower delta T)
Outlet refrigeration system
The system has a maximum cooling capacity of 59.7 kW and uses an axial fan to move an air volume of 19,584 m3/h at maximum capacity.
The system has 2 scroll compressors with 1 refrigeration circuit. R410A is used as refrigerant.
System sound pressure level
The sound pressure level at a distance of 10 meters from the system is 50.3 dB(A) according to ISO3744:210, with a sound power level of 81 dB according to UIN EN ISO 9614.
Sound hood concept
Aluminum frame construction to accommodate soundproof aluminum service doors for air outlet and air inlet and integration around the system.
The acoustic hood is designed for an air volume of 20,100 m3/h, the system can be operated in the acoustic hood without pressure loss.
The basic construction has the following dimensions: 1'700 x 1'700 x 2'635 mm (L x W x H)
Service doors with internal 40 mm thick sound insulation are integrated around the systems.
These service doors are equipped with quick-release fasteners that can be easily removed by one person. In this way we ensure unhindered access for service and maintenance work.
The insulation material offers high sound insulation over the entire frequency spectrum.
The insulation is also water and UV resistant and does not build up bacteria and fungi.
The insulation also corresponds to the highest fire safety class.
Advantages of the sound hood
All-round high sound reduction between 18 and 20 dB(A).
Protection of the systems against weather influences (direct sunlight, rain, hail, wind.
Unrestricted access to the facilities for service and maintenance work.
All components of the acoustic hood are recyclable
The Mitsubishi Air Sourec heat pump series SHW112YAA has the following dimensions: 1,050 x 480 x 1,020 mm (W x D x H).
The system on the image was set up at our test site prior to shipment to the customer. The system has an axial fan with a maximum air flow rate of 4,800 m3/h. sound hood concept The basic structure of the acoustic hood is an aluminum plug-in profile frame, the service doors around the system and in the roof 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. Because the laminated polyethylene foam absorbs sound and does not reflect it, it is an excellent alternative to many noise control materials used today.
The insulation is also moisture-resistant, does not build up mold, can be rinsed off with a high-pressure cleaner and corresponds to the fire protection class: B-S2-d0 (hardly inflammable).
The base frame of the acoustic hood has the following dimensions: 1,700 x 1,100 x 1,400 mm (L x W x H) with a weight of 90 kg.
The entry of the supply air at the rear can be on the right or left. The air outlet is mirrored traffic on the side in front. The acoustic hood is designed for an air flow rate of 5,100 m3/h.
The average air outlet speed is 1.7 m/sec. so that we hardly transmit any sound. Details acoustic hood
The all-round noise reduction across the frequency spectrum from 63 to 8,000 Hz is between 19 and 21 dB(A).
Adaptation to the environment
The acoustic hood is made entirely of aluminum and produced in the RAL color of your choice.
1'100 x 420 x 1'200 mm (L x W x H)
Maximum air volume Heat pumps
Heat Pumps: 4'200 m3/h
Air Conditioning: 3'500 m3/h
VRF/VRV systems: 3'500 m3/h
Pressure loss through the sound hood
about 18 pascals RAL
Manufactured in Black
Completely made of aluminum isolation 40 mm thick, the insulation is flame retardant and corresponds to fire class EN 13501-1 B-s2-d0 DIN4102: B1
The outdoor unit of the tabletop evaporators only consist of the condenser and the fans, the compressor is located in the interior. The challenge was to eliminate airborne noise in a high frequency range. Since the systems are on/off systems, they run continuously on the maximum air volume of 10,300 m3 / h.
Each unit each has the following dimensions: 2,006 x 956 x 1,268 mm L x W x H. The systems are mounted next to each other with a small gap.
The acoustic enclosure for the 2 systems has the dimensions: 2,006 x 956 x 1,268 mm (L x W x H). The hood was built to accommodate 2 table top evaporators and is 2,600 x 3,100 x 1,500 mm (L x W x H).
The sound reduction measured according to the enveloping surface method is 15 to 16 dB (A).
The acoustic hood is made entirely of aluminum. The basic construction is an aluminum plug-in system that is easy to assemble. Service doors were installed around the system, which allow unrestricted access to the system for service and maintenance work.
The inside of the acoustic hood is covered with 40 mm thick insulation (Stratocell Whisper).
The air inlet is guided at the bottom and blown out on the long sides at the top. An air short circuit is avoided by a transnorm sheet that separates the air chambers.
The sound hood was set up on our premises before shipping and we loaded it pre-assembled so that it can only be lifted over the system like a hat on site.
For more information:
A "Panasonic Mini VRF system U-5LE2E8" was installed on an intermediate roof between two single-family houses near Frankfurt.
The system has the following dimensions: 980 x 370 x 996 (+ 200 vibration dampers) mm (W x D x H).
At maximum output, the system has an air volume of 4,320 m3 / h, the static pressure of the fan is around 15 to 20 Pascal. When planning the acoustic hoods, we assumed a static pressure of <15 Pascal.
By means of the acoustic hood, the noise level is reduced to the neighborhood, the next window is around 7 meters away from the acoustic hood.
Acoustic hood concept
The air inlet is at the rear (condenser side towards the roof). This enables us to achieve an even air flow to the condenser without causing a pressure loss due to excessive air deflection.
The air outlet is on the front side (fan side), front left. A deflector plate was also installed here at the air outlet, which ensures the air outlet speed of 1.4 meters / sec. continues to insulate.
In this way, we achieve a continuous flow of exhaust air without creating an air short circuit. With an air outlet speed of around 1.4 m/sec. hardly any sound is transmitted via the air outlet.
The basic structure of the acoustic hood is based on aluminum system profiles which have the advantage of being light in weight when mounted on the roof. Around the system as well as in the enclosures roof, aluminum sheets were installed as easy-to-open service doors with a thickness of 1.5 mm with internal 50 mm insulation made of closed-cell, semi-rigid and sound-absorbing polyethylene foam sheets (Stratocell Whisper). Due to its sound-absorbing properties, this foam is one of the most innovative materials for sound control in HVAC systems.
The insulation is UV and water resistant and non-flammable. The isolation does not build up bacteria or fungi. And has strong sound insulation across all frequency bands. In this way we prevent masking effects that often occur when eliminating high-frequency sound bands and which lead to an increase in the tonality of the compressor sound.
The insulation is also light and hardly increases the weight of the service doors.
Sound hood dimensions
The acoustic hood has the following dimensions: 1,700 x 1,300 x 1,100mm (W x H x D) / weight including service doors 127 kg. The acoustic hood is made entirely of aluminum and was subsequently powder-coated in RAL color 7016 to match the color of the roof.
Sound reduction between 18 to 20 dB (A)
A total of six acoustic enclosures for six tabletop Heat Pump evaporator modules were created for this project. Since the heat pumps are in series, the air inlet and the air outlet have been moved on both sides.
The cold air is blown out on the side opposite the air outlet so that an air short circuit between the air inlet and the air outlet is impossible. The air chambers are separated by a deflector plate in the middle of the hood. The air outlet going up is deflected by 90° and thus the airborne sound is broken.
The sound reduction on all sides is around 19 dB (A) over the entire frequency band.
The hoods each have the size of: 1'700 x 1'000 x 1'700 mm (L x W x H) and are completely made of aluminum and then powder-coated in RAL color 9003. The systems are freely accessible for service and maintenance work via service doors that are installed around the systems.
The sound hoods were delivered to the construction site in AMSTERDAM pre-assembled.
The picture shows a acoustic enclosure for a Carrier refrigeration system with four axial fans with vertical air flow and an air volume of 28,900 m3/h at the highest performance level.
The system is used to cool the production rooms of a food manufacturer and is in the immediate vicinity of a residential area. Noise complaints from residents led to the system being fitted with a sound barrier.
The acoustic hood offers the following advantages:
Noise reduction over the entire frequency band of -19 dB (A) so that the system also fulfills the maximum permitted sound level for residential areas of 35 dB (A) in the evening and after hours at the next immission location (nearest window to the system). #
The acoustic hood is made entirely of aluminum and powder-coated in RAL color 9006.
Infrared refrigerant sensors with a detection limit of ≤ 10 ppm, which are built into the hood, warn the operator of even the slightest loss of refrigerant. The sound enclosure was delivered to the construction site pre-assembled in 4 parts and set up on the additional concrete foundation built around the system in less than 2 hours.
Our unique Environmental Enclosure systems provide a complete package solution for larger HVAC equipment, where noise and visual constraints are an issue on your project.