Saving energy for ventilation using decentralised duct fans

In conventional mechanical ventilation systems with constant air volume (CAV) airflows are often balanced using balancing flat plate dampers. The purpose of the dampers is to obtain nominal airflows to the individual zones or rooms in the building. Unfortunately, this procedure leads to increased pressure drops which in turn will increase energy use.
This paper presents a novel procedure for balancing CAV-systems using decentralised duct fans instead of flat plate dampers. The procedure will result in lower pressure drops and consequently in a reduction of energy use for ventilation when compared to a conventional mechanical ventilation system with flat plate dampers. Theoretical calculations and experimental observations for the investigated systems show that the power demand for distribution of air can be reduced about 30%.
The work carried out forms part of an ongoing PhD-project on mechanical ventilation systems with low energy use for new and renovation of buildings.