The EastLink tunnel in Melbourne has had its tunnel ventilation system upgraded to dynamically alter the system depending on traffic levels.
The tunnel’s operators say this upgrade has slashed the ventilation system’s electricity usage by two-thirds reducing GHG emissions by 9,000 tonnes CO2-e annually, and halved the audible noise from the ventilation system.
It says that since the opening of EastLink, the speed of airflows within the tunnels and stacks was controlled in a traditional way, by switching individual fans on and off at pre-programmed times of the day. When switched on, a fan always operated at full speed but that now the ten large ventilation fans have been upgraded from fixed speed fully off / fully on operation and now the ventilation system responds dynamically and in close to real-time for the volume of traffic travelling through the tunnels based on the vehicle mix such as the proportion of large heavy vehicles, and prevailing weather conditions such as wind speed and direction.
It says that electricity usage has reduced by 68%, saving approximately 6.2 GWh each year, audible noise from the ventilation stacks has halved and there have also been savings in maintenance costs and longer lifespans for tunnel ventilation equipment.