TABLE OF CONTENTS - The Professional Green Building Council

Theme C: Education and Market Transformationthe need to install a costly full BMS replacement. The specific controls strategiesidentified varied considerably from building to building. The relative merit ofthese different approaches is a topic worthy of a separate paper. A sample of themost common measures is presented below:Time of use control: Perhaps the simplest saving that can be made is turning off aservice when it is not needed. Time of use control modifications within thesebuildings included reduced run hours for central plant, and switchoff achieved byusing triggered sensors such as occupancy sensors.Condenser water control: Significant savings were identified throughmodification of condenser water system controls. Examples include modifying thecondenser water temperature to track the wet bulb temperature plus three degrees,Thereby improving chiller efficiency, and modifications to cooling tower stagingor VSDs.Boiler temperature lockouts: Most buildings within the sample included gasfired boilers. Significant gas and electricity savings were available throughlocking out the operation of these boilers based upon outdoor air temperaturecriteria.Economy cycle control: Whilst most buildings incorporated an economy cycle toincrease the quantity of outside air above the minimum when conditions werefavourable, the methodologies for control often led to substantial losses of energy.For instance, enthalpy based economy cycle controls were controlled based upon asingle outside air RH sensor, leading to system failure upon the failure of a singlesensor.Air handler fan control: Considerable energy savings were identified from theoptimisation of air handler controls. Whilst control points were not generallysufficient to allow complex reset methodologies, such as critical zone pressurereset, a general strategy of resetting air handler pressures based between594