AirFlowSetpointControl

The AirFlowSetpointControl component determines the effective setpoint for regulating the airflow using the damper, based on the output from the temperature control loop for cooling or heating, the setpoints for the minimum and maximum airflow for cooling and heating, the current occupancy status, operating mode (normal, balancing), and HVAC mode.

The AirFlowSetpointControl component has the following slots:

• Status: informs about the status of the component; if the Operating Mode/OccupancyStatus/HVAC Mode slot or one of the demand input slots has a null value then the status is fault, otherwise it is OK;

  • Available statues: OK, Fault, Disabled, Unlicensed, Down, Error;

• Effective Airflow Setpoint: returns an airflow setpoint calculated based on the output of the temperature control loop (heating or cooling) and taking into account the setpoint limit values for heating or cooling (Max Occupied Cool Airflow, Max Occupied Heat Airflow, Min Occupied Cool Airflow, Min Occupied Heat Airflow), occupancy mode and occupancy setpoints (UnoccAirflowSetpoint, StandbyAirflowSetpoint);

• Operating Mode: shows the operating mode from the BMS or panel (from Modbus/BACnet network point) and allows to initiate an airflow setpoint balancing procedure;

  • Available settings: Auto, MaxFlow, MinFlow, UserFlow;

• HVAC Mode: receives the HVAC mode setting, which determines the ariflow setting dependencies and impacts functioning of the fan and heaters (if available on the system);

  • Available settings: Auto, Heat, MorningWarmUp, Cool, NightPurge, PreCool, Off, Fire;

• Occupancy Status: shows the value coming from the OccupancyCalculator component which is an occupancy status resulting from the values of window contact, present motion, network occupancy, schedule occupancy, airflow detection, and panel button override;

  • Available settings: Occupied, Unoccupied; Standby, Bypass;

• Cool Demand: shows the value from the cooling PID loop;

• Heat Demand: shows the value from the heating PID loop;

• Co2 Demand: shows the value from the CO₂ PID loop;

• Dual Heat: provides the component with the DualHeat function status to adjust the effective airflow setpoint calculations in the occupied mode;

  • Available settings:

    • Yes (the DualHeat function active):

      • primary stage (from HeatPriority):

        • for heating demand in the range of 0-50%, scales the effective airflow setpoint between the MinHeatOccAirflowSetpoint and MaxHeatOccAirflowSetpoint values;

        • for heating demand over 50%, effective airflow setpoint equals the MaxHeatOccAirflowSetpoint;

      • secondary stage (from HeatPriority):

        • for heating demand in the range of 0-50%, effective airflow setpoint equals the MinHeatOccAirflowSetpoint;

        • for heating demand over 50%, scales the effective airflow setpoint between the MinHeatOccAirflowSetpoint and MaxHeatOccAirflowSetpoint values;

    • No (the DualHeat function not active);

• Heat Priority: provides the component with the heating stages priority to adjust the effective airflow setpoint calculations in the occupied mode as described above;

  • Available settings: primary (true), secondary (false);

• Max Occupied Cool Airflow: receives a maximum airflow setpoint in the occupied state, set during the balancing process;;

• Max Occupied Heat Airflow: receives a maximum airflow setpoint in the occupied state, set during the balancing process;;

• Min Occupied Cool Airflow: receives a maximum airflow setpoint in the occupied state, set during the balancing process;;

• Min Occupied Heat Airflow: receives a maximum airflow setpoint in the occupied state, set during the balancing process;;

• Standby Airflow: receives an airflow setpoint set from the BMS system and, optionally, from the local room panel, when the room is temporarily unoccupied;

• Unoccupied Airflow: receives an airflow setpoint set from the BMS system and, optionally, from the local room panel, when the room is unoccupied;

• User Airflow: receives an airflow setpoint set for tests in the balancing process;

• Startup Fan Airflow: receives a value of minimum airflow starting the parallel fan; after the Startup Fan Delay time has elapsed, normal control starts (airflow control according to the calculated setpoint);

• Fan Type: allows to select a preferred fan type as series or parallel; version without fan is None;

• Fan Active: the rising state on this slot causes the Startup Fan Airflow setpoint to be used for the time specified in the Startup Fan Delay slot; after the time has elapsed, normal control starts;

• Startup Fan Delay: allows to set a startup time with a minimum airflow specified in the Startup Fan Airflow slot;

• Unit Selector: allows to set the unit type.

More

More on airflow setpoint as used in the VAV application: Airflow