Energy efficiency power plans by optimizing air supply control
An energy plant requires air for combustion and for cooling. More and more Internal Combustion Engines are installed that can start quickly in order to provide instant power on moments when nature cannot provide sufficient solar or wind-energy. It is important to run these plants as efficiently as possible. In order to meet the specifications to ensure efficient operation. The way in which this is provided is often overlooked. The relevance of these aspects is shown in a whitepaper.
Energy label for attenuators (paper / excel tool / manual)
Within larger building air need to travel far. In order to get the required pressure to overcome this large ventilation units are required that produce a lot of noise. That noise needs to be attenuated both inside and outside in order to re-establish acceptable noise levels. These attenuators also result to additional pressure losses. With the current technology that uses heat pumps, heat exchangers and recirculation, the ventilation is often uses most energy of the entire building. ESC and Alara-Lukagro b.v. have created a tool together in order to evaluate the energy efficiency of attenuators. You can evaluate both the project or the individual attenuator. You can download a tool (EXCEL2013 or higher-based). Please read the short manual. The publication on the creation of the energy efficiency label tool can be downloaded here. Please notice the doesn’t require the presence of an actual attenuator, but does need noise requirements in order to establish an energy label.
Predictability of acoustic engineering
Alara-Lukagro b.v. submitted a paper on the evaluation of noise engineering for the International Congress on Acoustics, Aachen 2019. After this research improvements were made both for Alara-Lukagro and ESC.
Directivity leakage in attenuators
One of the main improvements was the introduction of acoustic leakage in attenuators based on the Fresnel bending potential in combination to the shape (and thus directivity) of the local propagated acoustic wave. A paper was created for DAGA 2020. The reverberant application of this theory has been compared to real projects, as can be seen in the publication for the ISMA 2022 CH.4. A combined paper was made available for this website.
Standing waves in ducts
One of the main challenges in the evaluation of complex channels is the accountability of reflective noise. Channels are also used in laboratories with ISO7235 testing of attenuators. A relatively complete picture on air bound acoustic waves in channels is found in the ISMA 2022 publication. A more detailed presentation just on reflections is at Congres Geluid, Trillingen en luchtkwaliteit 2022.
Low frequency hearing threshold
For the VVM Rob Hoffman asked Alara-Lukagro if their acoustic laboratory could be made periodically available for evaluation measurements of the low frequency hearing threshold on individuals. A lot of discussion is unfortunately present on whether or not the low frequency noise measured at locations where people suffer low frequency noise is audible or not. Most times the low frequency noise is even below background low frequency noise, so the test conditions are hard to get right. Once acceptable test conditions were created, a number of volunteers was tested to test the test. Not only turned the hearing threshold much lower than in previous studies. A signal with an impulse character proved to be even much better audible. Click her for the full publication.