.Buildings.Obsolete.Controls.OBC.ASHRAE.G36_PR1.AHUs.MultiZone.VAV.SetPoints.SupplyFan .Buildings.Obsolete.Controls.OBC.ASHRAE.G36_PR1.AHUs.MultiZone.VAV.SetPoints.SupplyFanSupply fan control for a multi zone VAV AHU according to ASHRAE guideline G36, PART 5.N.1 (Supply fan control).
have_duaDucBox=true)
or the AHU does not have airflow measurement station (have_airFloMeaSta=false),
sum the current airflow rate from the VAV boxes and output to a software point.Static pressure setpoint shall be reset using trim-respond logic using following parameters as a starting point:
| Variable | Value | Definition |
|---|---|---|
| Device | AHU Supply Fan | Associated device |
| SP0 | iniSet | Initial setpoint |
| SPmin | minSet | Minimum setpoint |
| SPmax | maxSet | Maximum setpoint |
| Td | delTim | Delay timer |
| T | samplePeriod | Time step |
| I | numIgnReq | Number of ignored requests |
| R | uZonPreResReq | Number of requests |
| SPtrim | triAmo | Trim amount |
| SPres | resAmo | Respond amount |
| SPres_max | maxRes | Maximum response per time interval |
Supply fan speed is controlled with a PI controller to maintain duct static pressure at setpoint
when the fan is proven on. The setpoint for the PI controller and the measured
duct static pressure are normalized with the maximum design static presssure
maxSet.
Where the zone groups served by the system are small,
provide multiple sets of gains that are used in the control loop as a function
of a load indicator (such as supply fan airflow rate, the area of the zone groups
that are occupied, etc.).
final keyword.