April 26, 2013

Abstract: 

The simplest, most effective, and most economical way to introduce fresh air in homes with central forced air systems is to use the central fan to pull in and distribute a controlled amount of outside air. The central fan integrated supply ventilation approach depends on two patented processes: fan cycling and ventilation damper cycling.

The simplest, most effective, and most economical way to introduce fresh air in homes with central forced air systems is to use the central fan to pull in and distribute a controlled amount of outside air. The most efficient approach to central fan integrated supply ventilation involves two patented process.1

FAN CYCLING: Fan cycling assures that the central air handler fan will run enough to distribute ventilation air and evenly mix air throughout the house, even when there is no demand for heating or cooling. But rather than operate the fan continuously or by a simple timer, the FanCycler™ method factors in prior operation—it does not run the central fan for ventilation when operation for heating or cooling has already accomplished the necessary ventilation and mixing. In this way, the FanCycler™ method saves energy as well as wear and tear on equipment.

VENTILATION DAMPER CYCLING – Integrating a motorized ventilation damper with fan cycling limits the potential for over-ventilation and saves the energy of unnecessarily conditioning this "extra" outside air. The damper opens when the fan comes on, but if the fan stays on longer than needed for the introduction of ventilation air, the damper automatically closes. The damper is simply re-cycled for as long as the fan continues to operate.

While BSC strongly recommends fan cycling with motorized damper control, the climate region where it is most important is hot-humid (because of the energy associated with moisture-laden outside air). . .

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Footnotes:

  1. The fan and damper cycling methods described here are protected by one or more of the following patents: US 5,547,017; 5,881,806; 6,431,268 CA 2,245,135.