HVAC Control in the New Millennium.pdf - HVAC.Amickracing

HVAC Control in the New MillenniumFire/Smoke EvacuationThe smoke pressurization sequence may involve all VAV air handlercontrollers as well as the zone controllers. Providing positive pressureon the floors above and below a fire may be part of these sequences.The fire floor may be controlled to a negative pressure with all zonesshut down, and return/exhaust fans at full volume.Smoke evacuation is a sequence which enables the exhaust andreturn fans on all units. Another technique to use separate smoke evacuationfans that are enabled when a fire occurs. In this case all VAV airhandlers are shut off to avoid introducing more air or interfering withthe smoke evacuation fans.Demand Limit ControlThis control technique raises the cooling setpoint in order to reducesome stages of cooling. This is a building-wide sequence that requiresequipment turn-off and avoids demand peaks. If companies know theirenergy profiles, how and when they consume power, they can negotiatebetter rates for the type and amount of power they need.Power MeasurementIntelligent devices and systems can monitor, measure, protect, coordinate,and control how power is distributed. Power and controlmonitoring systems use meters, protective relays, circuit break trip units,and motor starters. They can communicate information over an Ethernetnetwork to a central location for remote monitoring, alarming, trending,and control.Power-monitoring software can be used to analyze energy use andpower quality. It can identify load profiles to help rate negotiation. Loadshaping involves the prediction of demand excursions for sheddingloads or starting generators to avoid setting new peaks. It can also beused to predict maintenance requirements or provide energy bills forindividual departments or areas for actual power use.Intelligent metering and monitoring systems offer a low-costmethod for quick energy saving practices. The Cutler-Hammer plant in©2001 by The Fairmont Press, Inc. All rights reserved.