partial model MixingVolumeReverseFlow "Test model for mixing volume with flow reversal" extends Modelica.Icons.Example; package Medium = Buildings.Media.Air "Medium model"; constant Boolean prescribedHeatFlowRate = false "Flag that affects what steady state balance is used in the volume"; parameter Modelica.SIunits.Pressure dp_nominal = 10 "Nominal pressure drop"; parameter Modelica.SIunits.MassFlowRate m_flow_nominal = 2.0 "Nominal mass flow rate"; Modelica.Fluid.Sources.MassFlowSource_T sou( redeclare package Medium = Medium, nPorts=1, m_flow=m_flow_nominal, use_m_flow_in=true, T=313.15) "Flow source and sink"; Sources.Boundary_pT bou( redeclare package Medium = Medium, T=303.15, nPorts=2) "Boundary condition"; replaceable Buildings.Fluid.MixingVolumes.MixingVolume volDyn constrainedby Buildings.Fluid.MixingVolumes.BaseClasses.PartialMixingVolume( redeclare package Medium = Medium, V=1, nPorts=2, m_flow_nominal=m_flow_nominal, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial) "Volume with dynamic balance"; replaceable Buildings.Fluid.MixingVolumes.MixingVolume volSte constrainedby Buildings.Fluid.MixingVolumes.BaseClasses.PartialMixingVolume( redeclare package Medium = Medium, final prescribedHeatFlowRate = prescribedHeatFlowRate, V=1, nPorts=2, m_flow_nominal=m_flow_nominal, energyDynamics=Modelica.Fluid.Types.Dynamics.SteadyState) "Volume with steady-state balance"; Modelica.Blocks.Math.Gain gain "Gain to add heat, moisture or trace substance flow rate"; Modelica.Fluid.Sources.MassFlowSource_T sou1( redeclare package Medium = Medium, nPorts=1, m_flow=m_flow_nominal, use_m_flow_in=true, T=313.15) "Flow source and sink"; Modelica.Blocks.Sources.Ramp m_flow( height=-2*m_flow_nominal, duration=10, offset=m_flow_nominal) "Mass flow rate"; equation connect(sou.ports[1], volDyn.ports[1]); connect(sou1.ports[1], volSte.ports[1]); connect(volSte.ports[2], bou.ports[1]); connect(volDyn.ports[2], bou.ports[2]); connect(sou.m_flow_in, m_flow.y); connect(m_flow.y, sou1.m_flow_in); connect(m_flow.y, gain.u); end MixingVolumeReverseFlow;

partial model MoistureMixingConservation "Partial for checking conservation of mass for independent mass fraction" extends Modelica.Icons.Example; package Medium = Buildings.Media.Air "Medium model"; Buildings.Fluid.Sources.MassFlowSource_h sou1( redeclare package Medium = Medium, nPorts=1, m_flow=2, X={0,1}) "Air source"; Buildings.Fluid.Sources.MassFlowSource_h sou2( redeclare package Medium = Medium, nPorts=1, m_flow=1, X={0,1}) "Air source"; Buildings.Fluid.MixingVolumes.MixingVolumeMoistAir vol( redeclare package Medium = Medium, massDynamics=Modelica.Fluid.Types.Dynamics.SteadyState, m_flow_nominal=1, V=1, nPorts=2, allowFlowReversal=false, energyDynamics=Modelica.Fluid.Types.Dynamics.SteadyState) "Mixing volume for adding water"; Buildings.Fluid.MixingVolumes.MixingVolumeMoistAir vol1( redeclare package Medium = Medium, massDynamics=Modelica.Fluid.Types.Dynamics.SteadyState, m_flow_nominal=1, V=1, nPorts=2, allowFlowReversal=false, energyDynamics=Modelica.Fluid.Types.Dynamics.SteadyState) "Mixing volume for adding water"; Buildings.Fluid.Sources.Boundary_pT sin(redeclare package Medium = Medium, nPorts=1) "Air sink"; Buildings.Fluid.MixingVolumes.MixingVolumeMoistAir vol2( redeclare package Medium = Medium, massDynamics=Modelica.Fluid.Types.Dynamics.SteadyState, m_flow_nominal=1, V=1, nPorts=2, allowFlowReversal=false, energyDynamics=Modelica.Fluid.Types.Dynamics.SteadyState) "Mixing volume for removing water"; Modelica.Blocks.Sources.Constant mWatFlo1(k=0.001) "Water mass flow rate 1"; Modelica.Blocks.Sources.Constant mWatFlo3(k=-(mWatFlo1.k + mWatFlo2.k)) "Withdrawn water rate"; Modelica.Blocks.Sources.Constant mWatFlo2(k=0.003) "Water mass flow rate 2"; Modelica.Blocks.Math.Add cheMasFra(k2=-1) "Check for water conservation"; Buildings.Fluid.Sensors.MassFractionTwoPort senMasFra( redeclare package Medium = Medium, m_flow_nominal=1, tau=0, allowFlowReversal=false) "Sensor for measuring water content"; Modelica.Blocks.Sources.Constant mWatFloSol "Solution mass fraction water"; Buildings.Fluid.Sensors.MassFlowRate senMasFlo(redeclare package Medium = Medium, allowFlowReversal=false) "Mass flow rate sensor"; Modelica.Blocks.Math.Add cheMasFlo(k2=-1) "Check for conservation of mass"; Modelica.Blocks.Sources.Constant mFloSol "Solution mass flow rate"; Sensors.EnthalpyFlowRate senSpeEnt( redeclare package Medium = Medium, allowFlowReversal=false, m_flow_nominal=1, tau=0) "Specific enthalpy flow rate sensor"; Modelica.Blocks.Math.Add cheSpeEnt(k2=-1) "Check for conservation of energy"; Modelica.Blocks.Sources.Constant hSol "Solution mass flow rate"; protected Modelica.Fluid.Interfaces.FluidPort_a port_a( redeclare package Medium = Medium) "Fluid port for using fluid stream mixing implementation"; equation connect(sou1.ports[1], vol.ports[1]); connect(sou2.ports[1], vol1.ports[1]); connect(mWatFlo1.y, vol.mWat_flow); connect(mWatFlo3.y, vol2.mWat_flow); connect(mWatFlo2.y, vol1.mWat_flow); connect(vol1.ports[2], port_a); connect(vol.ports[2], port_a); connect(port_a, vol2.ports[1]); connect(mWatFloSol.y,cheMasFra. u1); connect(senMasFlo.port_b, senMasFra.port_a); connect(vol2.ports[2], senSpeEnt.port_a); connect(senSpeEnt.port_b, senMasFlo.port_a); connect(hSol.y,cheSpeEnt. u1); connect(mFloSol.y,cheMasFlo. u1); connect(senMasFra.port_b, sin.ports[1]); end MoistureMixingConservation;

model TraceSubstanceConservation "This test checks if trace substance mass flow rates are conserved" extends Modelica.Icons.Example; constant String substanceName="CO2"; package Medium = Buildings.Media.Air(extraPropertiesNames={substanceName}); Buildings.Fluid.Sources.MassFlowSource_h sou( redeclare package Medium = Medium, nPorts=1, m_flow=1, X={0.01,0.99}, C=fill(0.001, Medium.nC)) "Air source with moisture and trace substances"; Buildings.Fluid.MixingVolumes.MixingVolumeMoistAir vol( redeclare package Medium = Medium, massDynamics=Modelica.Fluid.Types.Dynamics.SteadyState, m_flow_nominal=1, V=1, nPorts=2, allowFlowReversal=false, energyDynamics=Modelica.Fluid.Types.Dynamics.SteadyState) "Mixing volume for adding moisture"; Modelica.Blocks.Sources.Constant mWatFlo(k=0.001) "Water mass flow rate "; Buildings.Fluid.Sensors.TraceSubstancesTwoPort senTraSubIn( redeclare package Medium = Medium, m_flow_nominal=1, tau=0, allowFlowReversal=false, substanceName=substanceName) "Measured inlet trace substance concentration"; Buildings.Fluid.Sensors.TraceSubstancesTwoPort senTraSubOut( redeclare package Medium = Medium, m_flow_nominal=1, tau=0, allowFlowReversal=false, substanceName=substanceName) "Measured outlet trace substance concentration"; Buildings.Fluid.Sources.Boundary_pT sin(redeclare package Medium = Medium, nPorts=1) "Air sink"; Sensors.MassFlowRate senMasFloIn(redeclare package Medium = Medium, allowFlowReversal=false) "Fluid mass flow rate at inlet"; Sensors.MassFlowRate senMasFloOut(redeclare package Medium = Medium, allowFlowReversal=false) "Fluid mass flow rate at outlet"; Modelica.Blocks.Math.Product CfloIn "Trace substance mass flow rate at inlet"; Modelica.Blocks.Math.Product CfloOut "Trace substance mass flow rate at outlet"; equation connect(mWatFlo.y, vol.mWat_flow); connect(sou.ports[1], senTraSubIn.port_a); connect(senTraSubIn.port_b, senMasFloIn.port_a); connect(senMasFloIn.port_b, vol.ports[1]); connect(sin.ports[1], senMasFloOut.port_b); connect(senMasFloOut.port_a, senTraSubOut.port_b); connect(CfloIn.u2, senTraSubIn.C); connect(CfloIn.u1, senMasFloIn.m_flow); connect(CfloOut.u1, senMasFloOut.m_flow); connect(CfloOut.u2, senTraSubOut.C); connect(vol.ports[2], senTraSubOut.port_a); end TraceSubstanceConservation;