performance with recent occupancy history as a fitness function to select the weighting values each wsu also keeps a record of set points reset points and ventilation rates in flash in 15 minute increments based on a one week calendar that can be altered by the occupants if the occupancy sensors or thermal sensors in a wsu are triggered a request is sent to the zc every 15 minutes the zc sends a command to the wsus to execute the occupancy prediction algorithm and returns any conditioning results to the zc if there is a conditioning request pending the zc opens a sufficient number of drus to keep the pressure of the ducts low enough to maintain a high enough air flow for heat transfer hvac central plant safety and to prevent damage to the duct system the drus to open is determined by current hvac needs and by near future hvac needs by the zc querying the wsus that will run their respective prediction algorithms for current and near future occupancy as well as distance from current set setback point from these values the zc opens the next most likely drus to open until enough are opened to provide adequate air.