Destratification fan can be speed controlled
Elta Fans has developed a destratification fan to overcome thermal stratification in high spaces. ZOO (Zone of Occupancy) units generate columns of air which direct warm air at high level down to the occupied zone. They can also be used in closer proximity as spot coolers, taking advantage of the evaporative-cooling sensation.
These fans use the FE2 Owlet sickle-bladed aerofoil-profile axial impeller powered by the speed-controllable Ziehl-Abegg external-rotor motor. Serrations on the trailing edge of the blades muffle sound, with further noise reduction achieved by winglets on each blade, like aircraft wings.
Destratifying an air mass uses more power than maintaining equilibrium. Once the air has been destratified, the fan speed can be turned down by 30 to 60%.
Alan Macklin, group technical manager, suggests that energy savings of 10 to 40% can be achieved for space heating.