Innovative tunnel ventilation system
The reversible MoJet® tunnel ventilation system can enhance the in-tunnel aerodynamic thrust delivered by other jetfans by up to 25%, depending on the installation location. To achieve such a significant improvement in performance, the MoJet® uses shaped nozzles which turn the airstream away from the tunnel soffit and walls. This reduces surface friction, minimising the Coanda Effect, where a reduction in static pressure due to the high jet velocity tends to deflect the jet towards any solid surface.
The MoJet® represents a significant improvement over older technologies to reduce the Coanda effect, such as the Banana Jet® and airflow deflectors (see our power comparison paper).
MoJets® can provide a number of significant benefits for tunnel design, construction and operation.
In terms of tunnel operation, the MoJet® can potentially offer the following benefits:
Reductions of up to 30% in the power consumption
for tunnel ventilation, leading to lower costs for energy and installed power, as well as a lower carbon footprint.
Reduced number of fans
and hence lower maintenance costs.
Smaller and lighter fans for the same aerodynamic thrust
improving handling during installation, as well as reducing overheads associated with commissioning and maintenance.
A significant reduction in sound pressure levels
can be achieved with the MoJet® by reducing the blade pitch angle, while still delivering the same in-tunnel aerodynamic thrust as a conventional jetfan.
If specified with 4-pole motors
MoJets® can offer significantly lower sound emissions compared to conventional jetfans.
During tunnel design and construction, the MoJet® can offer the following benefits:
A smaller tunnel cross-section
leading to a reduced requirement for construction materials and contributing to a faster construction programme.
Reduced cabling costs
since MoJets® can be installed much closer together than conventional jetfans.
Additional ventilation capacity
For existing tunnels, additional ventilation capacity can be delivered without the need for installing tunnel niches.