Design methodology and economic evaluation of central-fan-integrated supply ventilation systems.

Residential ventilation systems can be categorized as supply, exhaust, or balanced systems.This effort focused on establishing a design methodology for central-fan-integrated supplyventilation systems. Air flow measurements were taken for 7.6 m lengths of 12.7 cm through22.9 cm diameter flexible ducts, with a 15.2 cm wall-cap, at duct pressures of -10 Pa to -120Pa. Using these measurements and field experience, a five-step method was developed as aguide for sizing and installing the ventilation system. An economic evaluation was made byconducting hourly computer simulations to determine the impact on heating, cooling, and fanenergy use for four U.S. climates. An effective ventilation system can be achieved using afiltered duct from outdoors to the return side of a central air distribution fan with a specializedfan control that automatically cycles the fan if the fan has been inactive for a period of time.