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

HVAC Control in the New Millenniumdecision-making circuits are combined with a customized program tomaximize demand and energy savings with a minimum impact on operatingconditions. The computer receives inputs from the electric meterand from sensors monitoring the critical loads in the building or facility.Loads may be cycled based on the following criteria:• maximum demand target,• time of day and day or week,• rate of demand increase,• heating and cooling temperatures,• pressures,• fuel flow and rates,• occupancy schedules,• inside and outside temperatures,• humidity,• wind direction and velocity and• combinations of the above factors.The durations are variable and can be changed automatically accordingto these parameters. A secondary demand target may be usedand if the primary demand target is exceeded other control actions areapplied.The demand target can float upward and downward according todemand rates, time of day, and other parameters. Different targets andcontrol strategies can be applied to different sections of buildings andplants. Reports and graphs showing the consumption by demand periodand by day, week, or month are provided.These systems can also be applied to manage the energy consumedby air conditioning systems. Intake and exhaust dampers are controlledon the basis of air temperatures, so that the mix of air requiring the leastenergy is obtained at all times. The start-up and shutdown of air conditioning,heating, and lighting systems can be regulated according toinside and outside temperatures as well as occupancy. The goal is toproduce the conditions which consume the least energy.©2001 by The Fairmont Press, Inc. All rights reserved.