Emission-Based Ventilation ControlCopyright: © ISAC
With regard to the ventilation of existing tunnels, there is potential for innovation. One example of this is the Einhorn Tunnel. The emission control ventilation currently used there extracts 90% of the tunnel air, and the electricity consumption for this process is 697 MWh per year. However, the process was designed for road traffic with considerably higher pollutant emissions than is the case today. For this reason, the use of the ventilation system is currently structured on the basis of time windows; the decisive factor here is not the pollutant load, but the speed at the exhaust stack. This is where the EmBaLu research project comes in: By means of in-situ pollutant measurements, the necessary air supply can be determined and the ventilation can be controlled according to demand.
The actual pollutant load is to be recorded in order to control the tunnel's emission control ventilation system as required in the future. Data obtained during the test will be used to validate existing forecasts. In addition, a correlation between NOx and CO concentrations will be determined. This will provide the basis for controlling the ventilation system according to demand, even beyond the trial period.
By means of an adaptive ventilation control, the electricity demand can probably be reduced by at least 30% and the annual CO2 emissions by 88t. This is accompanied by operating cost savings of approx. 57,000€ per year.
Various measurements will be carried out in the Einhorn Tunnel, such as CO and visual turbidity measurements inside the tunnel or measurement of NOx loads at the tunnel portals and the exhaust stack. At the same time, traffic behavior is recorded and traffic flows are linked to pollutant concentrations, and a causal relationship is established between NOx and CO/CO2 levels. In addition, weather data is used, which is recorded at the tunnel portals and taken into account when performing dispersion calculations for the pollutants.