A concern with any air conditioning plant has always been the avoidance of intrusive noise levels. This applies as much to the community as to the occupants of a particular building or industrial site.

With internal plant in an isolated space, use of water cooled chillers and acoustic insulation is a relatively straightforward solution, but for roof mounted plant the user has to be aware of his neighbours and any local byelaws affecting noise levels.

In dense urban areas, this becomes a major concern and will be an important element of the specification for both commercial comfort and industrial process requirements, with major cities being particularly stringent in this area. At night, mandatory levels may be set even lower, particularly relevant to hospitals, hotels, some leisure complexes and 24/7 operation of industrial processes.

Rooftop chillers, by nature, will produce mechanical and air flow noise from compressors and fans and through careful design the Hitachi Samurai range has become the quietest choice for many applications. There are a number of reasons why this is so, not least being the quality of engineering used in construction and attention to all aspects of sound and vibration.

Foremost is the adoption of highly efficient, semi hermetic screw compressors, with immediate benefits over reciprocating technologies because of their smooth running and balanced operation. The low sound and vibration is further damped by the use of rubber mounting pads that protect the structure of the chiller from adverse vibration. Not content with that, Hitachi enclose the units using acoustic insulating materials to absorb sound to the lowest level feasible.

The Hitachi designed 6 pole fans have also been developed to reduce noise, without impairing air circulation and ensuring this is sufficient for correct operation of the chiller at all loads. There are also options for low noise and extra low noise versions which employ slower rotating 8 pole fans and additional insulation to reach even lower sound levels.

Hitachi Samurai's modular construction has further benefits to offer in suppressing overall noise in multiple module configurations. The accepted standard is for multi unit plant is an increased noise level of 3dBA for each additional unit. However, because each Samurai chiller is constructed from individual modules to create a completely self contained, balanced unit, the build up of noise and vibration is closely controlled and limited to just a few decibels across the complete range of units from 100 - 1100kW.

For a more detailed review of sound data, please consult the Hitachi Samurai Technical Guide, available from Axair Climate Limited.

The Hitachi Samurai range, supplied exclusively in the UK by Axair Climate , from which full product and technical information is available. Now acknowledged as one of the quietest running chillers on the market, the range is well suited to a wide variety of air conditioning and process specifications and has become the choice of many frontline projects in recent years.

Please don’t hesitate to contact us on our free phone number 0800 801 819 or contact our Applied Products Division Manager on the email address given below.