A project to install a new on-demand tunnel ventilation system, one of the first of its type in the world, on Melbourne’s M3 EastLink tolled motorway has been awarded the 2018 National Industry Award by ITS Australia.
The National Awards celebrate the achievements of the intelligent transportation systems industry in Australia, and recognize professional expertise and raise awareness across all levels of government and society about the benefits of ITS technology to cities and communities, the economy, environment, transportation and everyday lives.
The award-winning EastLink project demonstrated many of these benefits by solving some of the drawbacks of conventional tunnel ventilation systems. Since the opening of the EastLink motorway, the speed of airflows within the tunnels and stacks was controlled in the 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, which EastLink identified as being highly inefficient and expensive to run.
In April 2018, EastLink completed the implementation of its award-winning innovative solution; the freeway tunnel ventilation on-demand (VoD) system. The highway’s Mullum Mullum and Melba one mile-long (1.6km) tunnels are equipped with 10 large ventilation fans that were upgraded from fixed-speed fully-off / fully-on operation to much more efficient self-regulating or closed loop variable speed operation.
New impellers designed for quiet efficient operation were installed within each of the existing ventilation fan housings and new variable speed drive motors were fitted to regulate their rotational speed. A new ventilation control system was also deployed, which uses real-time data from air quality and air flow sensors to dynamically control the speed and number of fans required to meet traffic demand.
For these works, each ventilation fan, weighing over 7 tonnes, was separately removed, upgraded off-site, and then re-installed within the tunnel complex in delicate operations conducted during nights when traffic was lowest.
Remarkably, almost no tunnel closures were required for these works. Traffic management was mostly limited to temporary lane closures while at least one lane remained operating. The results of the new tunnel ventilation on demand system have exceeded expectations:
• Ventilation system electricity usage was reduced by 68%, saving approximately 6.2GWh each year;
• This electricity usage reduction has reduced GHG emissions from power stations by an estimated 9,000 tonnes CO₂-e annually;
• Audible noise from the ventilation stacks has halved, confirmed by noise measurements, reducing disturbance for local residents;
• A temporary monitoring station has verified that air quality standards in the local community have not been compromised through the introduction of the new VoD system.
“We are delighted that our innovative tunnel ventilation on demand system has won the 2018 ITS Australia National Industry Award. The new system has delivered significant benefits in reductions of power usage, GHG emissions, and audible noise for local residents,” commented EastLink’s corporate affairs and marketing manager, Doug Spencer-Roy.
“We hope that winning this award encourages other tunnel operators in Australia and overseas to upgrade ventilation systems as we have done, and for developers to consider ventilation on demand for future freeway tunnel construction projects.”