Until recently you had two choices for residential air filtration. First, the traditional pleated media filter that strains larger particles out of the air stream. Extended surface filters (not "furnace" filters) capture only larger particles, restrict air flow and must be replaced every few months. Second, electronic air cleaners create an electric field that charges particles. These particles attach themselves to oppositely charged collector plates. These units offer less air flow resistance and capture smaller particles than media filters. However, they operate properly only when clean, and frequent cleaning is needed. In addition, electronic air cleaners generate ozone, which may be good in the stratosphere, but is unhealthy in homes.

Now there is a third choice. Nutech Energy Systems has developed the Turbulent Flow Precipitator that promises highly effective filtration, low airflow resistance, very little maintenance and zero ozone.

The TFP is based on the idea that air flowing near the wall of a duct is turbulent. This turbulence flings suspended particles against the duct walls. Particles bounce off the hard surfaces and are picked up again by the swirling air. In a TFP, the walls trap the particles.

The TFP contains an internal fan that forces air through a labyrinth. The walls of the labyrinth are pleated fabric that hold particles thrown out by the air stream. The unit can operate for years without changing the pleated fabric.

The TFP attaches to the duct system of a heat recovery ventilator or a forced heating system.

Nutech claims that the TFP will capture 100 percent of the particles larger than 5 microns, 98 percent of those between 5 and 1 microns, and 90 percent of particles between 1 and 0.5 microns. (You can find a detailed description of filter performance in the February 1994 issue.)

Contact:

American Aldes Ventilation Corp.