In a cogeneration plant with combustion engines, electricity and heat (often intended for a heating application) are produced simultaneously, by the means of a heat transfer involving the exhaust gases (at high temperature) and an exchanger.
This mode of energy production is often based on high power industrial engines, whose noise emissions are important and must be controlled to preserve the neighborhood of any nuisance e.g. in relation to the emergence of noise of the installation compared to the residual noise (especially during the night period).
In such a context, the exhaust is always a major concern.
Indeed, the noise of the engines, even if attenuated by different components of the exhaust line such as the exchanger, the catalyst (if there is one), the different elbows as well as the entry of the chimney, can be at the origin of a sound power level, at the outlet of the chimney, likely to impact very negatively the sound environment, a fortiori if the limit of property is close and if all the usual noises in the absence of installation noise is low (this is often the case in rural areas).
ITS participated in the design and supply of a silencer for a cogeneration plant near Caen (Calvados department, Normandy region - France).
This soundproofing device was intended to achieve an acoustic pressure level of 10 meters as low as 50 dB (A) ref. 20 μPa, while creating a total pressure loss as low as 10 mbar for an exhaust gas flow (at a temperature of the order of 400 degrees C) of the order of 15 tons per hour for a motor of which the noise emissions were characterized by an exhaust sound power level close to 130 dB (A) ref. 1 pW, with a very marked tonal component in the octave band centered on 125 Hz.
Combining a reactive stage and a dissipative stage, the silencer has been sized to have the required acoustic performances (i.e. as resulting from a calculation note prepared by ITS, taking into account the data mentioned above as well as the directivity of the chimney and its attenuation).
Manufactured with care in a specialized boilermaking workshop, and delivered in record time, this efficient soundproofing equipment has given complete satisfaction.