Frog technology quietens all systems
Concern about environmental noise continues to grow, with air conditioners and refrigeration plant mounted at roof level being seen as particularly difficult areas to tackle
Problem:.
Machines can, of course, always be silenced by putting them in sealed boxes lined with sound-absorbing material. But how then is air going to get in and/or out?
Solution: Refrigeration engineer Rhys Schrivener has patented a solution called the Frogbox – a concept which is now in commercial production in Southampton. His idea, put basically, is to put the relevant machinery inside a box which is then enclosed in a second, outer box.
In the case of refrigeration plant, air is drawn into the passages between the tops and bottoms of the boxes, passed over the heat exchanger elements, and then exhausted through the passages between the sides of the boxes; the passages are lined with mineral wool. Air entering the enclosure is turned through 180º before encountering the heat exchanger and again through 180º before exiting.
Application: The arrangement reduces sound emissions by 20dBA, reducing the noise level of a typical unit to about 25dBA at 10m in free field conditions.
In essence, this makes it virtually inaudible. Extra fan energy consumption is typically around 5%.
Retrofit work is currently being undertaken in conjunction with Westminster City Council while the Frogbox design is approved as an accessory by Dakin Air Conditioners and Mitsubishi Heavy Industries.
Projects are now underway to develop products suitable for use with Honda generators in the USA and for pumps made by Jacuzzi. TS
(Frogbox)
Frogbox Enter 529
