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

TypeNameDefaultDescription
RealtrueHoldDuration60true hold duration
RealfalseHoldDurationtrueHoldDurationfalse hold duration
Nominal condition
Modelica.Units.SI.MassFlowRatem_flow_nominalNominal mass flow rate
Modelica.Units.SI.PressureDifferencedpValve_nominal5000Valve pressure drop at nominal conditions
Dynamics › Conservation equations
Modelica.Fluid.Types.DynamicsenergyDynamicsModelica.Fluid.Types.Dynamics.FixedInitialType of energy balance (except for the pump always modeled in steady state)

Components

TypeNameDefaultDescription
Modelica.Fluid.Interfaces.FluidPort_bport_bSupSupply line outlet port
Modelica.Fluid.Interfaces.FluidPort_bport_bRetReturn line outlet port
Modelica.Fluid.Interfaces.FluidPort_aport_aSupSupply line inlet port
Modelica.Fluid.Interfaces.FluidPort_aport_aRetReturn line inlet port
Buildings.Controls.OBC.CDL.Interfaces.RealInputmRev_flowService water mass flow rate in reverse direction
Buildings.Controls.OBC.CDL.Interfaces.RealInputmPos_flowService water mass flow rate in positive direction
Buildings.DHC.ETS.BaseClasses.JunctionsplSupFlow splitter
Buildings.DHC.ETS.BaseClasses.JunctionsplRetFlow splitter
Buildings.DHC.ETS.Combined.Controls.SwitchBoxconSwitch box controller
Fluid.Actuators.Valves.ThreeWayEqualPercentageLinearvalSupDirectional valve
Fluid.Actuators.Valves.ThreeWayEqualPercentageLinearvalRetDirectional valve

Contents

NameDescription
MediumMedium 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.