blockReliefDamper
Relief damper control for AHUs using actuated dampers without fan
Information
Sequence for controlling actuated relief damper yRelDam for AHUs using
actuated relief damper without a fan.
It is implemented according to Section 5.18.8 of ASHRAE Guideline G36, May 2020.
In Section 3.2.2.3, find the relief damper position setpoint limits:
-
relDam_min: the relief damper position that maintainx a building pressure of 12 Pa (0.05 in. of water) while the economizer is positioned to provide minimum outdoor airflow while the supply fan is at minimum speed. -
relDam_max: the relief damper position that maintainx a building pressure of 12 Pa (0.05 in. of water) while the economizer damper is fully open and the fan speed is at cooling maximum.
Relief damper shall be enabled when the associated supply fan is proven on and any outdoor air damper is open, and disabled and closed otherwise.
Relief damper position shall be reset lineary from relDam_min to
relDam_max as the commanded economizer damper position goes from
uOutDam_min to 100% open.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Real | relDam_min | Relief-damper position that maintains a building pressure of 12 Pa while the economizer damper is positioned to provide minimum outdoor air while the supply fan is at minimum speed | |
| Real | relDam_max | Relief-damper position that maintains a building pressure of 12 Pa while the economizer damper is fully open and the fan speed is at cooling maximum | |
| Advanced | |||
| Real | posHys | 0.05 | Hysteresis for damper position check |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Buildings.Controls.OBC.CDL.Interfaces.RealInput | uOutDam_min | Outdoor air damper minimum position | |
| Buildings.Controls.OBC.CDL.Interfaces.RealInput | uOutDam | Outdoor damper position | |
| Buildings.Controls.OBC.CDL.Interfaces.BooleanInput | u1SupFan | Supply fan command on | |
| Buildings.Controls.OBC.CDL.Interfaces.RealOutput | yRelDam | Relief damper commanded position |
Revisions
-
May 20, 2021, by Jianjun Hu:
First implementation.