modelSwitchBox
Model for mass flow rate redirection with three-port two-position directional valves
Information
This model represents a hydronic arrangement avoid flow reversal in the service line, for instance when connecting an energy transfer station such as the one modeled in Buildings.DHC.ETS.Combined.HeatPumpHeatExchanger. For that intent, two three-port two-position directional valves are used. The valves are actuated based on the logic described in Buildings.DHC.ETS.Combined.Controls.SwitchBox.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Real | trueHoldDuration | 60 | true hold duration |
| Real | falseHoldDuration | trueHoldDuration | false hold duration |
| Nominal condition | |||
| Modelica.Units.SI.MassFlowRate | m_flow_nominal | Nominal mass flow rate | |
| Modelica.Units.SI.PressureDifference | dpValve_nominal | 5000 | Valve pressure drop at nominal conditions |
| Dynamics › Conservation equations | |||
| Modelica.Fluid.Types.Dynamics | energyDynamics | Modelica.Fluid.Types.Dynamics.FixedInitial | Type of energy balance (except for the pump always modeled in steady state) |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Fluid.Interfaces.FluidPort_b | port_bSup | Supply line outlet port | |
| Modelica.Fluid.Interfaces.FluidPort_b | port_bRet | Return line outlet port | |
| Modelica.Fluid.Interfaces.FluidPort_a | port_aSup | Supply line inlet port | |
| Modelica.Fluid.Interfaces.FluidPort_a | port_aRet | Return line inlet port | |
| Buildings.Controls.OBC.CDL.Interfaces.RealInput | mRev_flow | Service water mass flow rate in reverse direction | |
| Buildings.Controls.OBC.CDL.Interfaces.RealInput | mPos_flow | Service water mass flow rate in positive direction |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Buildings.DHC.ETS.BaseClasses.Junction | splSup | Flow splitter | |
| Buildings.DHC.ETS.BaseClasses.Junction | splRet | Flow splitter | |
| Buildings.DHC.ETS.Combined.Controls.SwitchBox | con | Switch box controller | |
| Fluid.Actuators.Valves.ThreeWayEqualPercentageLinear | valSup | Directional valve | |
| Fluid.Actuators.Valves.ThreeWayEqualPercentageLinear | valRet | Directional valve |
Contents
| Name | Description |
|---|---|
 Medium | Medium model |
Revisions
-
March 27, 2024, by David Blum:
Update icon.
This is for issue #3606. -
February 23, 2021, by Antoine Gautier:
Refactored with three-way valves instead of pumps.
This is for issue 1769. -
January 16, 2020, by Michael Wetter:
Added documentation.