blockSetpoint
Minimum flow setpoint calculation
Information
The minimum flow setpoint is determined as follows, to provide minimum flow through all operating units.
- For the units commanded on in the stage, calculate the highest ratio of minimum flow rate to design flow rate.
- Calculate the minimum flow setpoint as the highest minimum flow ratio multiplied by the sum of the design flow rates for the operating equipment.
Details
For plants consisting of identical units, the minimum flow setpoint is the minimum flow of each unit multiplied by the number of units enabled in the stage.
If the units have different minimum flow to design flow ratios, just maintaining the sum of the minimum flows will not satisfy the equipment with the highest relative minimum flows. Note that this also requires that equipment be balanced to distribute flow proportional to their design flow.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Integer | nEqu | 0 | Number of plant equipment |
| Real[:] | V_flow_nominal | Design flow rate – Each unit | |
| Real[:] | V_flow_min | Minimum flow rate – Each unit |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Buildings.Controls.OBC.CDL.Interfaces.BooleanInput[nEqu] | u1 | Equipment enable command | |
| Buildings.Controls.OBC.CDL.Interfaces.RealOutput | VPriSet_flow | Primary flow setpoint |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Buildings.Controls.OBC.CDL.Reals.Sources.Constant[nEqu] | floMin | Minimum flow rate | |
| Buildings.Controls.OBC.CDL.Conversions.BooleanToReal[nEqu] | booToRea | Convert to real signal | |
| Buildings.Controls.OBC.CDL.Reals.Multiply[nEqu] | floMinEna | Minimum flow for enabled equipment | |
| Buildings.Controls.OBC.CDL.Reals.Divide[nEqu] | ratFloMinEna | Minimum flow ratio for enabled equipment | |
| Buildings.Controls.OBC.CDL.Reals.Sources.Constant[nEqu] | floDes | Design flow rate | |
| Buildings.Controls.OBC.CDL.Reals.MultiMax | maxRatFloMinEna | Maximum of minimum flow ratio for enabled equipment | |
| Buildings.Controls.OBC.CDL.Reals.Multiply[nEqu] | floDesEqu | Design flow for enabled equipment | |
| Buildings.Controls.OBC.CDL.Reals.MultiSum | sumFloDesEna | Sum of design flow for enabled equipment | |
| Buildings.Controls.OBC.CDL.Reals.Multiply | floMinSet | Minimum flow setpoint |
Revisions
-
May 31, 2024, by Antoine Gautier:
First implementation.