blockActiveAirFlow
Output the active airflow setpoint for dual-duct terminal unit with cold-duct minimum control
Information
This sequence sets the active cooling and heating maximum and the active minimum setpoints for dual-duct terminal unit with cold-duct minimum control. The implementation is according to the Section 5.14.4 of ASHRAE Guideline 36, May 2020.
The setpoints shall vary depending on the mode of the zone group.
| Setpoint | Occupied | Cooldown | Setup | Warm-up | Setback | Unoccupied |
|---|---|---|---|---|---|---|
Cooling maximum (VActCooMax_flow) | VCooMax_flow |
VCooMax_flow | VCooMax_flow |
0 | 0 | 0 |
Minimum (VActMin_flow) | VOccMin_flow | 0 | 0 | 0 | 0 | 0 |
Heating maximum (VActHeaMax_flow) | VHeaMax_flow |
0 | 0 | VHeaMax_flow | VHeaMax_flow |
0 |
Note that the designer must ensure that the minimum (VOccMin_flow) and heating
maximum (VHeaMax_flow) sum to less
than the cooling maximum (VCooMax_flow) to avoid oversupplying the diffusers.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Real | VCooMax_flow | Design zone cooling maximum airflow rate | |
| Real | VHeaMax_flow | Design zone heating maximum airflow rate | |
| Advanced | |||
| Real | floHys | Near zero flow rate, below which the flow rate or difference will be seen as zero | |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Buildings.Controls.OBC.CDL.Interfaces.RealInput | VOccMin_flow | Occupied minimum airflow setpoint | |
| Buildings.Controls.OBC.CDL.Interfaces.IntegerInput | uOpeMod | Zone operation mode | |
| Buildings.Controls.OBC.CDL.Interfaces.RealOutput | VActCooMax_flow | Active cooling maximum airflow setpoint | |
| Buildings.Controls.OBC.CDL.Interfaces.RealOutput | VActMin_flow | Active minimum airflow setpoint | |
| Buildings.Controls.OBC.CDL.Interfaces.RealOutput | VActHeaMax_flow | Active heating maximum airflow setpoint |
Revisions
-
August 1, 2020, by Jianjun Hu:
First implementation.