Entry Date:
December 12, 1997

Ventilation Control Strategies

Principal Investigator Leslie Norford

Building space-conditioning systems often perform at poor part-load efficiencies because there is limited information feedback from individual offices and because part-load operation has led to large throttling losses. The increased use of microelectronics and power electronics in building control systems offers two benefits for ventilation systems: first, fans can be controlled not by adjusting dampers that throttle flow but by regulating the speed of the motor; and second, by communicating with digital rather than analog flow-regulation dampers in each occupied space, the central fan can be slowed to the speed that minimizes pressure drops across these dampers. A recently completed program tested and analyzed both of these benefits, with the goal of quantifying energy savings and providing to building owners, control manufacturers and electric utilities the information needed to make informed decisions about investing in new technologies. The performance of ventilation systems was monitored in several buildings and models were developed to correlate fan power with airflow and pressure.