The new flow controller. Source: VTTVTT Technical Research Centre of Finland and Fläkt Woods Oy have developed a new flow sensor that enables ventilation to adapt to actual demand resulting in improved air quality and energy efficiency.

Based on ultrasound, the flow sensor is ideal for use in hospital conditions and schools.

Today’s ventilation systems are based on estimated average occupancy rates and don’t adapt to unexpected changes. In this project, the new flow sensor allows for reliable measurement across the entire speed range, even at low flow rates. This takes place without dirt gathering or bulky measuring devices needed and it is maintenance-free, quiet, precise and does not cause pressure drops.

"Our flow sensor is based on ultrasound technology,” says Anu Kärkkäinen, researcher at VTT. “An ultrasound pulse is transmitted in the radial direction of the air channel and is measured differentially. This measurement system enables us to eliminate several sources of error and obtain highly accurate measurements.”

Researchers say the flow controllers provide the right volume of air to be pumped into a room based on the current load. This drops the lifecycle costs of the property when the ventilation works precisely and is demand controlled, the team says. This ultimately could result in a reduction of energy costs by 45 percent to 50 percent.

VTT says it will launch the flow sensor to Finnish and Swedish markets initially beginning in September.