On October 13 and 14, the Wind Engineering and Fluid Mechanics Working Group, together with colleagues from the Technical Meteorology Department at the University of Hamburg and the Institute for Combustion and Power Plant Technology at the University of Stuttgart, hosted a technical discussion at Ruhr University on "Improving the immission situation in residential areas by adapting discharge conditions - Alternative Measures to Chimney Height Increase."

Representatives from the chimney sweep trade, industry associations, authorities and ministries, expert agencies and manufacturers of combustion plants and filter systems came together to discuss the results presented by the project group. Since 1 January 2022, new regulations for the discharge of exhaust gases have applied to newly constructed solid fuel combustion plants in accordance with Section 19 of the 1st BImSchV. These are based on the VDI 3781 Sheet 4 guideline. Existing plants were exempted from the new regulations.

The research project ‘Improvement of the immission situation in residential areas by adapting discharge conditions – alternative measures to chimney heightening’ (Federal Environment Agency, FKZ 3722 19 301 0) is intended to record and document in more detail for the Federal Environment Agency (UBA) the relationships between plant technology, emission behaviour, discharge conditions and the immission situation in the neighbourhood. The research project is being carried out in collaboration with the Meteorological Institute of the University of Hamburg, the Institute for Combustion and Power Plant Technology at the University of Stuttgart and the Wind Engineering and Fluid Mechanics Working Group at the Ruhr University Bochum. To this end, model tests are being carried out to quantitatively investigate the influence of discharge conditions on the immission situation in the vicinity of solid fuel combustion in residential areas. These model tests are carried out according to a comprehensive concept, both on the physical model in a qualified boundary layer wind tunnel and in extensive simulation calculations using a qualified numerical model (computational fluid dynamics, CFD).
On the other hand, technical measures to reduce emissions and thus also immissions are to be identified and quantified, particularly with regard to existing plants. The aim is to determine which alternative plant engineering measures are possible in order to achieve an equivalent immission situation in the neighbourhood as with a chimney height increase for the discharge of exhaust gases in accordance with the state of the art (VDI 3781 Sheet 4).
In addition to providing information to invited experts, the workshop was intended to serve as a forum for discussing relevant practical aspects so that these could be taken into account in the further course of the project.