LBL logo

Buildings.Fluid.Interfaces.Examples

Collection of models that illustrate model use and test models

Information

This package contains examples for the use of models that can be found in Buildings.Fluid.Interfaces.

Extends from Modelica.Icons.ExamplesPackage (Icon for packages containing runnable examples).

Package Content

Name Description
Buildings.Fluid.Interfaces.Examples.ConservationEquation ConservationEquation Model that tests the conservation equation
Buildings.Fluid.Interfaces.Examples.HeaterCooler_u HeaterCooler_u Model that tests a heat exchanger model with reverse flow
Buildings.Fluid.Interfaces.Examples.Humidifier_u Humidifier_u  
Buildings.Fluid.Interfaces.Examples.PrescribedOutletState PrescribedOutletState Test model for prescribed outlet state
Buildings.Fluid.Interfaces.Examples.ReverseFlowHumidifier ReverseFlowHumidifier Model that tests the reverse flow for a humidifier
Buildings.Fluid.Interfaces.Examples.ReverseFlowMassExchanger ReverseFlowMassExchanger Model that tests the reverse flow for a mass exchanger
Buildings.Fluid.Interfaces.Examples.StaticTwoPortConservationEquation StaticTwoPortConservationEquation Model that tests the static two port conservation equation

Buildings.Fluid.Interfaces.Examples.ConservationEquation Buildings.Fluid.Interfaces.Examples.ConservationEquation

Model that tests the conservation equation

Buildings.Fluid.Interfaces.Examples.ConservationEquation

Information

Model that tests the conservation equations that are used for the heat and mass balance.

Extends from Modelica.Icons.Example (Icon for runnable examples).

Modelica definition

model ConservationEquation "Model that tests the conservation equation" extends Modelica.Icons.Example; package Medium = Buildings.Media.Water "Medium model"; Buildings.Fluid.Interfaces.ConservationEquation dyn(redeclare package Medium = Medium, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial, nPorts=2, fluidVolume=0.01, use_mWat_flow=true) "Dynamic conservation equation"; Buildings.Fluid.Interfaces.StaticTwoPortConservationEquation ste( redeclare package Medium = Medium, m_flow_nominal=0.01, show_T=true, use_mWat_flow=true) "Steady-state conservation equation"; Modelica.Blocks.Sources.Constant mWat_flow(k=0) "Water mass flow rate added to the control volume"; Modelica.Blocks.Sources.TimeTable QSen_flow(startTime=0, table=[ 0,-100; 900,-100; 900,0; 1800,0; 1800,100]) "Sensible heat flow rate added to the control volume"; Buildings.Fluid.Sources.Boundary_pT sin( nPorts=2, use_p_in=false, redeclare package Medium = Medium, p=101325, T=283.15); Buildings.Fluid.FixedResistances.FixedResistanceDpM res1( from_dp=true, redeclare package Medium = Medium, m_flow_nominal=0.01, dp_nominal=100) "Flow resistance"; Buildings.Fluid.Sources.MassFlowSource_T bou( nPorts=2, redeclare package Medium = Medium, m_flow=0.01) "Boundary condition for mass flow rate"; Buildings.Fluid.FixedResistances.FixedResistanceDpM res2( from_dp=true, redeclare package Medium = Medium, m_flow_nominal=0.01, dp_nominal=100) "Flow resistance"; equation connect(QSen_flow.y, dyn.Q_flow); connect(mWat_flow.y, dyn.mWat_flow); connect(bou.ports[1], dyn.ports[1]); connect(res1.port_b, sin.ports[1]); connect(QSen_flow.y, ste.Q_flow); connect(mWat_flow.y, ste.mWat_flow); connect(res2.port_b, sin.ports[2]); connect(ste.port_a, bou.ports[2]); connect(ste.port_b, res2.port_a); connect(dyn.ports[2], res1.port_a); end ConservationEquation;

Buildings.Fluid.Interfaces.Examples.HeaterCooler_u Buildings.Fluid.Interfaces.Examples.HeaterCooler_u

Model that tests a heat exchanger model with reverse flow

Buildings.Fluid.Interfaces.Examples.HeaterCooler_u

Information

Model that tests the basic class that is used for the heater models. It adds and removes heat for forward and reverse flow. The top and bottom models should give similar results, although the sign of the temperature difference over the components differ because of the reverse flow. The model uses assert statements that will be triggered if results that are expected to be close to each other differ by more than a prescribed threshold. All temperature sensors are configured as steady-state sensors to avoid differences in temperature due to the dynamic response of the sensor.

Extends from Modelica.Icons.Example (Icon for runnable examples).

Modelica definition

model HeaterCooler_u "Model that tests a heat exchanger model with reverse flow" extends Modelica.Icons.Example; package Medium = Buildings.Media.Water; Buildings.Fluid.HeatExchangers.HeaterCooler_u hea1( redeclare package Medium = Medium, Q_flow_nominal=5000, m_flow_nominal=0.5, dp_nominal=200, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial, massDynamics=Modelica.Fluid.Types.Dynamics.DynamicFreeInitial) "Heater and cooler"; Modelica.Blocks.Sources.Constant TDb(k=293.15) "Drybulb temperature"; Buildings.Fluid.Sources.Boundary_pT sou_1( redeclare package Medium = Medium, use_T_in=true, nPorts=4, p(displayUnit="Pa") = 101735, T=293.15); Buildings.Fluid.FixedResistances.FixedResistanceDpM res_11( redeclare package Medium = Medium, dp_nominal=5, m_flow_nominal=0.5); Buildings.Fluid.FixedResistances.FixedResistanceDpM res_12( redeclare package Medium = Medium, dp_nominal=5, m_flow_nominal=0.5); Buildings.Fluid.Sources.Boundary_pT sin_1( redeclare package Medium = Medium, use_p_in=true, T=288.15, nPorts=4); Modelica.Blocks.Sources.Constant POut(k=101325); Modelica.Blocks.Sources.Ramp u( height=2, duration=3600, offset=-1, startTime=0) "Control signal"; Buildings.Fluid.HeatExchangers.HeaterCooler_u hea2( redeclare package Medium = Medium, Q_flow_nominal=5000, m_flow_nominal=0.5, dp_nominal=200, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial) "Heater and cooler"; Modelica.Blocks.Math.Gain gain(k=-1); Buildings.Fluid.HeatExchangers.HeaterCooler_u hea3( redeclare package Medium = Medium, Q_flow_nominal=5000, m_flow_nominal=0.5, dp_nominal=200, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial, massDynamics=Modelica.Fluid.Types.Dynamics.DynamicFreeInitial) "Heater and cooler"; Buildings.Fluid.FixedResistances.FixedResistanceDpM res_2( redeclare package Medium = Medium, dp_nominal=5, m_flow_nominal=0.5); Buildings.Fluid.FixedResistances.FixedResistanceDpM res_3( redeclare package Medium = Medium, dp_nominal=5, m_flow_nominal=0.5); Buildings.Fluid.HeatExchangers.HeaterCooler_u hea4( redeclare package Medium = Medium, Q_flow_nominal=5000, m_flow_nominal=0.5, dp_nominal=200, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial) "Heater and cooler"; Buildings.Fluid.FixedResistances.FixedResistanceDpM res_4( redeclare package Medium = Medium, dp_nominal=5, m_flow_nominal=0.5); Buildings.Fluid.MixingVolumes.MixingVolume mix1( redeclare package Medium = Medium, V= 0.000001, nPorts=2, m_flow_nominal=0.5, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial); Buildings.Utilities.Diagnostics.AssertEquality ass1( threShold= 0.05, startTime=600); Buildings.Utilities.Diagnostics.AssertEquality ass2( threShold= 0.05, startTime=600); Buildings.Fluid.HeatExchangers.HeaterCooler_u hea5( redeclare package Medium = Medium, Q_flow_nominal=5000, m_flow_nominal=0.5, dp_nominal=200, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial, massDynamics=Modelica.Fluid.Types.Dynamics.DynamicFreeInitial) "Heater and cooler"; Buildings.Fluid.FixedResistances.FixedResistanceDpM res_1( redeclare package Medium = Medium, dp_nominal=5, m_flow_nominal=0.5); Buildings.Fluid.FixedResistances.FixedResistanceDpM res_5( redeclare package Medium = Medium, dp_nominal=5, m_flow_nominal=0.5); Buildings.Fluid.HeatExchangers.HeaterCooler_u hea6( redeclare package Medium = Medium, Q_flow_nominal=5000, m_flow_nominal=0.5, dp_nominal=200, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial) "Heater and cooler"; Buildings.Fluid.HeatExchangers.HeaterCooler_u hea7( redeclare package Medium = Medium, Q_flow_nominal=5000, m_flow_nominal=0.5, dp_nominal=200, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial, massDynamics=Modelica.Fluid.Types.Dynamics.DynamicFreeInitial) "Heater and cooler"; Buildings.Fluid.FixedResistances.FixedResistanceDpM res_6( redeclare package Medium = Medium, dp_nominal=5, m_flow_nominal=0.5); Buildings.Fluid.FixedResistances.FixedResistanceDpM res_7( redeclare package Medium = Medium, dp_nominal=5, m_flow_nominal=0.5); Buildings.Fluid.HeatExchangers.HeaterCooler_u hea8( redeclare package Medium = Medium, Q_flow_nominal=5000, m_flow_nominal=0.5, dp_nominal=200, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial) "Heater and cooler"; Buildings.Fluid.FixedResistances.FixedResistanceDpM res_8( redeclare package Medium = Medium, dp_nominal=5, m_flow_nominal=0.5); Buildings.Fluid.MixingVolumes.MixingVolume mix2( redeclare package Medium = Medium, V=0.000001, nPorts=2, m_flow_nominal=0.5, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial); Buildings.Utilities.Diagnostics.AssertEquality ass9( threShold=0.05, startTime=600); Buildings.Utilities.Diagnostics.AssertEquality ass10( threShold=0.05, startTime=600); Buildings.Fluid.Sensors.TemperatureTwoPort senTem2a(redeclare package Medium = Medium, m_flow_nominal=0.5, tau=0) "Temperature sensor"; Buildings.Fluid.Sensors.TemperatureTwoPort senTem2b(redeclare package Medium = Medium, m_flow_nominal=0.5, tau=0) "Temperature sensor"; Buildings.Fluid.Sensors.TemperatureTwoPort senTem1a(redeclare package Medium = Medium, m_flow_nominal=0.5, tau=0) "Temperature sensor"; Buildings.Fluid.Sensors.TemperatureTwoPort senTem1b(redeclare package Medium = Medium, m_flow_nominal=0.5, tau=0) "Temperature sensor"; Buildings.Fluid.Sensors.TemperatureTwoPort senTem3a(redeclare package Medium = Medium, m_flow_nominal=0.5, tau=0) "Temperature sensor"; Buildings.Fluid.Sensors.TemperatureTwoPort senTem3b(redeclare package Medium = Medium, m_flow_nominal=0.5, tau=0) "Temperature sensor"; Buildings.Fluid.Sensors.TemperatureTwoPort senTem4a(redeclare package Medium = Medium, m_flow_nominal=0.5, tau=0) "Temperature sensor"; Buildings.Fluid.Sensors.TemperatureTwoPort senTem4b(redeclare package Medium = Medium, m_flow_nominal=0.5, tau=0) "Temperature sensor"; Buildings.Utilities.Diagnostics.AssertEquality ass3( threShold= 0.05, startTime=600); Buildings.Utilities.Diagnostics.AssertEquality ass4( threShold= 0.05, startTime=600); Buildings.Utilities.Diagnostics.AssertEquality ass5( threShold= 0.05, startTime=600); Buildings.Utilities.Diagnostics.AssertEquality ass6( threShold= 0.05, startTime=600); Buildings.Fluid.Sensors.TemperatureTwoPort senTem6b(redeclare package Medium = Medium, m_flow_nominal=0.5, tau=0) "Temperature sensor"; Buildings.Fluid.Sensors.TemperatureTwoPort senTem6a(redeclare package Medium = Medium, m_flow_nominal=0.5, tau=0) "Temperature sensor"; Buildings.Fluid.Sensors.TemperatureTwoPort senTem5b(redeclare package Medium = Medium, m_flow_nominal=0.5, tau=0) "Temperature sensor"; Buildings.Fluid.Sensors.TemperatureTwoPort senTem5a(redeclare package Medium = Medium, m_flow_nominal=0.5, tau=0) "Temperature sensor"; Buildings.Utilities.Diagnostics.AssertEquality ass7( threShold= 0.05, startTime=600); Buildings.Utilities.Diagnostics.AssertEquality ass8( threShold= 0.05, startTime=600); Buildings.Fluid.Sensors.TemperatureTwoPort senTem8b(redeclare package Medium = Medium, m_flow_nominal=0.5, tau=0) "Temperature sensor"; Buildings.Fluid.Sensors.TemperatureTwoPort senTem8a(redeclare package Medium = Medium, m_flow_nominal=0.5, tau=0) "Temperature sensor"; Buildings.Fluid.Sensors.TemperatureTwoPort senTem7b(redeclare package Medium = Medium, m_flow_nominal=0.5, tau=0) "Temperature sensor"; Buildings.Fluid.Sensors.TemperatureTwoPort senTem7a(redeclare package Medium = Medium, m_flow_nominal=0.5, tau=0) "Temperature sensor"; equation connect(POut.y,sin_1. p_in); connect(TDb.y,sou_1. T_in); connect(u.y, hea1.u); connect(gain.y, hea2.u); connect(u.y, gain.u); connect(u.y, hea3.u); connect(gain.y, hea4.u); connect(u.y, hea6.u); connect(u.y, hea8.u); connect(gain.y, hea5.u); connect(gain.y, hea7.u); connect(sin_1.ports[1], res_12.port_a); connect(sin_1.ports[2], res_3.port_a); connect(sou_1.ports[1], res_11.port_a); connect(sou_1.ports[2], res_2.port_a); connect(sin_1.ports[3], res_1.port_a); connect(sin_1.ports[4], res_6.port_a); connect(sou_1.ports[3], res_5.port_a); connect(sou_1.ports[4], res_7.port_a); connect(mix1.ports[1], res_4.port_a); connect(mix2.ports[1], res_8.port_a); connect(senTem1a.T, ass1.u1); connect(senTem2a.T, ass1.u2); connect(senTem1b.T, ass2.u2); connect(senTem2b.T, ass2.u1); connect(senTem4a.T, ass4.u2); connect(senTem3a.T, ass4.u1); connect(senTem4b.T, ass3.u1); connect(senTem3b.T, ass3.u2); connect(senTem6a.T, ass6.u2); connect(senTem5a.T, ass6.u1); connect(senTem6b.T, ass5.u1); connect(senTem5b.T, ass5.u2); connect(senTem8a.T, ass8.u2); connect(senTem7a.T, ass8.u1); connect(senTem8b.T, ass7.u1); connect(senTem7b.T, ass7.u2); connect(senTem3a.T, ass10.u1); connect(senTem7a.T, ass10.u2); connect(senTem2b.T, ass9.u1); connect(senTem5b.T, ass9.u2); connect(res_12.port_b, senTem2a.port_a); connect(senTem2a.port_b, hea2.port_a); connect(hea2.port_b, senTem2b.port_a); connect(senTem2b.port_b, senTem1b.port_b); connect(hea1.port_b, senTem1b.port_a); connect(res_11.port_b, senTem1a.port_a); connect(senTem1a.port_b, hea1.port_a); connect(res_2.port_b, senTem3a.port_a); connect(senTem3a.port_b, hea3.port_a); connect(hea3.port_b, senTem3b.port_a); connect(senTem3b.port_b, mix1.ports[2]); connect(hea4.port_b, senTem4b.port_a); connect(res_3.port_b, senTem4a.port_a); connect(senTem4a.port_b, hea4.port_a); connect(senTem4b.port_b, res_4.port_b); connect(res_5.port_b, senTem6a.port_a); connect(senTem6a.port_b, hea6.port_a); connect(hea6.port_b, senTem6b.port_a); connect(senTem6b.port_b, senTem5b.port_b); connect(senTem5b.port_a, hea5.port_b); connect(hea5.port_a, senTem5a.port_b); connect(senTem5a.port_a, res_1.port_b); connect(res_7.port_b, senTem8a.port_a); connect(senTem8a.port_b, hea8.port_a); connect(hea8.port_b, senTem8b.port_a); connect(senTem8b.port_b, res_8.port_b); connect(mix2.ports[2], senTem7b.port_b); connect(senTem7b.port_a, hea7.port_b); connect(hea7.port_a, senTem7a.port_b); connect(senTem7a.port_a, res_6.port_b); end HeaterCooler_u;

Buildings.Fluid.Interfaces.Examples.Humidifier_u Buildings.Fluid.Interfaces.Examples.Humidifier_u


Buildings.Fluid.Interfaces.Examples.Humidifier_u

Information

Model that tests the basic class that is used for the humidifier model. It adds and removes water for forward and reverse flow. The top and bottom models should give similar results, although the sign of the humidity difference over the components differ because of the reverse flow. The model uses assert statements that will be triggered if results that are expected to be close to each other differ by more than a prescribed threshold.

Extends from Modelica.Icons.Example (Icon for runnable examples).

Parameters

TypeNameDefaultDescription
MassFlowRatemWat_flow_nominal0.001Nominal water mass flow rate [kg/s]

Modelica definition

model Humidifier_u extends Modelica.Icons.Example; package Medium = Buildings.Media.Air; parameter Modelica.SIunits.MassFlowRate mWat_flow_nominal = 0.001 "Nominal water mass flow rate"; Humidifier hea1(redeclare package Medium = Medium, m_flow_nominal=0.5, mWat_flow_nominal=mWat_flow_nominal, dp_nominal=50, show_T=true, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial, massDynamics=Modelica.Fluid.Types.Dynamics.DynamicFreeInitial) "Heater and cooler"; Modelica.Blocks.Sources.Constant TDb(k=293.15) "Drybulb temperature"; Buildings.Fluid.Sources.Boundary_pT sou_1( redeclare package Medium = Medium, use_T_in=true, nPorts=4, p(displayUnit="Pa") = 101435, T=293.15); Buildings.Fluid.FixedResistances.FixedResistanceDpM res_11( redeclare package Medium = Medium, dp_nominal=5, m_flow_nominal=0.5); Buildings.Fluid.FixedResistances.FixedResistanceDpM res_12( redeclare package Medium = Medium, dp_nominal=5, m_flow_nominal=0.5); Buildings.Fluid.Sources.Boundary_pT sin_1( redeclare package Medium = Medium, use_p_in=true, T=288.15, nPorts=4); Modelica.Blocks.Sources.Constant POut(k=101325); Modelica.Blocks.Sources.Ramp u( duration=3600, startTime=0, height=1, offset=0) "Control signal"; Humidifier hea2( redeclare package Medium = Medium, m_flow_nominal=0.5, mWat_flow_nominal=mWat_flow_nominal, dp_nominal=50, show_T=true, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial) "Heater and cooler"; Modelica.Blocks.Math.Gain gain(k=-1); Humidifier hea3( redeclare package Medium = Medium, m_flow_nominal=0.5, mWat_flow_nominal=mWat_flow_nominal, dp_nominal=50, show_T=true, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial, massDynamics=Modelica.Fluid.Types.Dynamics.DynamicFreeInitial) "Heater and cooler"; Buildings.Fluid.FixedResistances.FixedResistanceDpM res_2( redeclare package Medium = Medium, dp_nominal=5, m_flow_nominal=0.5); Buildings.Fluid.FixedResistances.FixedResistanceDpM res_3( redeclare package Medium = Medium, dp_nominal=5, m_flow_nominal=0.5); Humidifier hea4( redeclare package Medium = Medium, m_flow_nominal=0.5, mWat_flow_nominal=mWat_flow_nominal, dp_nominal=50, show_T=true, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial) "Heater and cooler"; Buildings.Fluid.FixedResistances.FixedResistanceDpM res_4( redeclare package Medium = Medium, dp_nominal=5, m_flow_nominal=0.5); Buildings.Fluid.MixingVolumes.MixingVolume mix1( redeclare package Medium = Medium, V=0.000001, nPorts=2, m_flow_nominal=0.5, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial); Buildings.Utilities.Diagnostics.AssertEquality ass1( startTime=0.3, threShold=0.05); Modelica.Blocks.Sources.RealExpression y1(y=hea2.staB.T); Modelica.Blocks.Sources.RealExpression y2(y=hea1.staB.T); Buildings.Utilities.Diagnostics.AssertEquality ass2( startTime=0.3, threShold=0.05); Modelica.Blocks.Sources.RealExpression y3(y=hea2.staA.T); Modelica.Blocks.Sources.RealExpression y4(y=hea1.staA.T); Buildings.Utilities.Diagnostics.AssertEquality ass3( startTime=0.3, threShold=0.05); Modelica.Blocks.Sources.RealExpression y5(y=hea4.staB.T); Modelica.Blocks.Sources.RealExpression y6(y=hea3.staB.T); Buildings.Utilities.Diagnostics.AssertEquality ass4( startTime=0.3, threShold=0.05); Modelica.Blocks.Sources.RealExpression y7(y=hea4.staA.T); Modelica.Blocks.Sources.RealExpression y8(y=hea3.staA.T); Humidifier hea5(redeclare package Medium = Medium, m_flow_nominal=0.5, mWat_flow_nominal=mWat_flow_nominal, dp_nominal=50, show_T=true, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial, massDynamics=Modelica.Fluid.Types.Dynamics.DynamicFreeInitial) "Heater and cooler"; Buildings.Fluid.FixedResistances.FixedResistanceDpM res_1( redeclare package Medium = Medium, dp_nominal=5, m_flow_nominal=0.5); Buildings.Fluid.FixedResistances.FixedResistanceDpM res_5( redeclare package Medium = Medium, dp_nominal=5, m_flow_nominal=0.5); Humidifier hea6( redeclare package Medium = Medium, m_flow_nominal=0.5, mWat_flow_nominal=mWat_flow_nominal, dp_nominal=50, show_T=true, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial) "Heater and cooler"; Humidifier hea7(redeclare package Medium = Medium, m_flow_nominal=0.5, mWat_flow_nominal=mWat_flow_nominal, dp_nominal=50, show_T=true, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial, massDynamics=Modelica.Fluid.Types.Dynamics.DynamicFreeInitial) "Heater and cooler"; Buildings.Fluid.FixedResistances.FixedResistanceDpM res_6( redeclare package Medium = Medium, dp_nominal=5, m_flow_nominal=0.5); Buildings.Fluid.FixedResistances.FixedResistanceDpM res_7( redeclare package Medium = Medium, dp_nominal=5, m_flow_nominal=0.5); Humidifier hea8( redeclare package Medium = Medium, m_flow_nominal=0.5, mWat_flow_nominal=mWat_flow_nominal, dp_nominal=50, show_T=true, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial) "Heater and cooler"; Buildings.Fluid.FixedResistances.FixedResistanceDpM res_8( redeclare package Medium = Medium, dp_nominal=5, m_flow_nominal=0.5); Buildings.Fluid.MixingVolumes.MixingVolume mix2( redeclare package Medium = Medium, V= 0.000001, nPorts=2, m_flow_nominal=0.5, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial); Buildings.Utilities.Diagnostics.AssertEquality ass5( startTime=0.3, threShold=0.05); Modelica.Blocks.Sources.RealExpression y9(y=hea6.staB.T); Modelica.Blocks.Sources.RealExpression y10( y=hea5.staB.T); Buildings.Utilities.Diagnostics.AssertEquality ass6( startTime=0.3, threShold=0.05); Modelica.Blocks.Sources.RealExpression y11( y=hea6.staA.T); Modelica.Blocks.Sources.RealExpression y12( y=hea5.staA.T); Buildings.Utilities.Diagnostics.AssertEquality ass7( startTime=0.3, threShold=0.05); Modelica.Blocks.Sources.RealExpression y13( y=hea8.staB.T); Modelica.Blocks.Sources.RealExpression y14( y=hea7.staB.T); Buildings.Utilities.Diagnostics.AssertEquality ass8( startTime=0.3, threShold=0.05); Modelica.Blocks.Sources.RealExpression y15( y=hea8.staA.T); Modelica.Blocks.Sources.RealExpression y16( y=hea7.staA.T); Buildings.Utilities.Diagnostics.AssertEquality ass9( startTime=0.3, threShold=0.05); Modelica.Blocks.Sources.RealExpression y17(y=hea2.staB.T); Modelica.Blocks.Sources.RealExpression y18(y=hea5.staB.T); Buildings.Utilities.Diagnostics.AssertEquality ass10( startTime=0.3, threShold=0.05); Modelica.Blocks.Sources.RealExpression y19(y=hea4.staA.T); Modelica.Blocks.Sources.RealExpression y20(y=hea7.staA.T); Buildings.Utilities.Diagnostics.AssertEquality ass11( threShold=1E-2, startTime=0.3); Modelica.Blocks.Sources.RealExpression y21(y=hea2.staB.X[1]); Modelica.Blocks.Sources.RealExpression y22(y=hea1.staB.X[1]); Buildings.Utilities.Diagnostics.AssertEquality ass12(threShold=1E-2, startTime= 0.3); Modelica.Blocks.Sources.RealExpression y23( y=hea2.staA.X[1]); Modelica.Blocks.Sources.RealExpression y24( y=hea1.staA.X[1]); Buildings.Utilities.Diagnostics.AssertEquality ass13(threShold=1E-2, startTime= 0.3); Modelica.Blocks.Sources.RealExpression y25( y=hea4.staB.X[1]); Modelica.Blocks.Sources.RealExpression y26( y=hea3.staB.X[1]); Buildings.Utilities.Diagnostics.AssertEquality ass14(threShold=1E-2, startTime= 0.3); Modelica.Blocks.Sources.RealExpression y27( y=hea4.staA.X[1]); Modelica.Blocks.Sources.RealExpression y28( y=hea3.staA.X[1]); Buildings.Utilities.Diagnostics.AssertEquality ass15(threShold=1E-2, startTime= 0.3); Modelica.Blocks.Sources.RealExpression y29( y=hea6.staB.X[1]); Modelica.Blocks.Sources.RealExpression y30( y=hea5.staB.X[1]); Buildings.Utilities.Diagnostics.AssertEquality ass16(threShold=1E-2, startTime= 0.3); Modelica.Blocks.Sources.RealExpression y31( y=hea6.staA.X[1]); Modelica.Blocks.Sources.RealExpression y32( y=hea5.staA.X[1]); Buildings.Utilities.Diagnostics.AssertEquality ass17(threShold=1E-2, startTime= 0.3); Modelica.Blocks.Sources.RealExpression y33( y=hea8.staB.X[1]); Modelica.Blocks.Sources.RealExpression y34( y=hea7.staB.X[1]); Buildings.Utilities.Diagnostics.AssertEquality ass18(threShold=1E-2, startTime= 0.3); Modelica.Blocks.Sources.RealExpression y35( y=hea8.staA.X[1]); Modelica.Blocks.Sources.RealExpression y36( y=hea7.staA.X[1]); Buildings.Utilities.Diagnostics.AssertEquality ass19(threShold=1E-2, startTime= 0.3); Modelica.Blocks.Sources.RealExpression y37(y=hea2.staB.X[1]); Modelica.Blocks.Sources.RealExpression y38(y=hea5.staB.X[1]); Buildings.Utilities.Diagnostics.AssertEquality ass20(threShold=1E-2, startTime= 0.3); Modelica.Blocks.Sources.RealExpression y39(y=hea4.staA.X[1]); Modelica.Blocks.Sources.RealExpression y40(y=hea7.staA.X[1]); protected model Humidifier "Model for humidifier that adds a variable for the thermodynamic states at its ports" extends Buildings.Fluid.MassExchangers.Humidifier_u; Medium.ThermodynamicState staA= Medium.setState_phX(port_a.p, actualStream(port_a.h_outflow), actualStream(port_a.Xi_outflow)) "Thermodynamic state in port a"; Medium.ThermodynamicState staB= Medium.setState_phX(port_b.p, actualStream(port_b.h_outflow), actualStream(port_b.Xi_outflow)) "Thermodynamic state in port b"; end Humidifier; equation connect(POut.y,sin_1. p_in); connect(TDb.y,sou_1. T_in); connect(res_11.port_b, hea1.port_a); connect(u.y, hea1.u); connect(gain.y, hea2.u); connect(u.y, gain.u); connect(res_12.port_b, hea2.port_a); connect(res_2.port_b, hea3.port_a); connect(u.y, hea3.u); connect(gain.y, hea4.u); connect(res_3.port_b, hea4.port_a); connect(hea4.port_b, res_4.port_b); connect(hea1.port_b, hea2.port_b); connect(y1.y, ass1.u1); connect(y2.y, ass1.u2); connect(y3.y, ass2.u1); connect(y4.y, ass2.u2); connect(y5.y, ass3.u1); connect(y6.y, ass3.u2); connect(y7.y, ass4.u1); connect(y8.y, ass4.u2); connect(res_1.port_b, hea5.port_a); connect(res_5.port_b, hea6.port_a); connect(res_6.port_b,hea7. port_a); connect(res_7.port_b,hea8. port_a); connect(hea8.port_b,res_8. port_b); connect(hea5.port_b,hea6. port_b); connect(y9.y,ass5. u1); connect(y10.y, ass5.u2); connect(y11.y, ass6.u1); connect(y12.y, ass6.u2); connect(y13.y, ass7.u1); connect(y14.y, ass7.u2); connect(y15.y, ass8.u1); connect(y16.y, ass8.u2); connect(y17.y,ass9. u1); connect(y18.y,ass9. u2); connect(y19.y, ass10.u1); connect(y20.y, ass10.u2); connect(u.y, hea6.u); connect(u.y, hea8.u); connect(gain.y, hea5.u); connect(gain.y, hea7.u); connect(y21.y, ass11.u1); connect(y22.y, ass11.u2); connect(y23.y, ass12.u1); connect(y24.y, ass12.u2); connect(y25.y, ass13.u1); connect(y26.y, ass13.u2); connect(y27.y, ass14.u1); connect(y28.y, ass14.u2); connect(y29.y, ass15.u1); connect(y30.y, ass15.u2); connect(y31.y, ass16.u1); connect(y32.y, ass16.u2); connect(y33.y, ass17.u1); connect(y34.y, ass17.u2); connect(y35.y, ass18.u1); connect(y36.y, ass18.u2); connect(y37.y, ass19.u1); connect(y38.y, ass19.u2); connect(y39.y, ass20.u1); connect(y40.y, ass20.u2); connect(sin_1.ports[1], res_12.port_a); connect(sin_1.ports[2], res_3.port_a); connect(sou_1.ports[1], res_11.port_a); connect(sou_1.ports[2], res_2.port_a); connect(sin_1.ports[3], res_1.port_a); connect(sin_1.ports[4], res_6.port_a); connect(sou_1.ports[3], res_5.port_a); connect(sou_1.ports[4], res_7.port_a); connect(hea3.port_b, mix1.ports[1]); connect(mix1.ports[2], res_4.port_a); connect(hea7.port_b, mix2.ports[1]); connect(mix2.ports[2], res_8.port_a); end Humidifier_u;

Buildings.Fluid.Interfaces.Examples.PrescribedOutletState Buildings.Fluid.Interfaces.Examples.PrescribedOutletState

Test model for prescribed outlet state

Buildings.Fluid.Interfaces.Examples.PrescribedOutletState

Information

Model that demonstrates the use of an ideal heater and an ideal cooler.

The heater model has an almost unlimited positive capacity (Q_flow_nominal = 1.0e10 Watts), and hence its outlet temperature always reaches the set point temperatures.

The cooler model has a limited negative capacitiy (Q_flow_nominal = 1000 Watts), and hence its outlet temperature reaches only a limited value corresponding to its maximum negative capacity.

There is also a heater and cooler with unlimited capacity.

At t=1000 second, the flow reverses its direction.

Each flow leg has the same mass flow rate. There are three mass flow sources as using one source only would yield a nonlinear system of equations that needs to be solved to determine the mass flow rate distribution.

The heater and cooler models have the parameter show_T set to true to allow inspecting the temperatures at their ports.

Extends from Modelica.Icons.Example (Icon for runnable examples).

Parameters

TypeNameDefaultDescription
MassFlowRatem_flow_nominal0.1Nominal mass flow rate [kg/s]

Modelica definition

model PrescribedOutletState "Test model for prescribed outlet state" extends Modelica.Icons.Example; package Medium = Buildings.Media.Water; parameter Modelica.SIunits.MassFlowRate m_flow_nominal=0.1 "Nominal mass flow rate"; Buildings.Fluid.Sources.Boundary_pT sin( redeclare package Medium = Medium, use_T_in=false, p(displayUnit="Pa"), T=293.15, nPorts=3) "Sink"; Buildings.Fluid.Interfaces.PrescribedOutletState heaHigPow( redeclare package Medium = Medium, Q_flow_maxHeat=1.0e10, m_flow_small=1E-4*abs(m_flow_nominal), show_T=true, m_flow_nominal=m_flow_nominal) "Steady-state model of the heater with high capacity"; Modelica.Blocks.Sources.TimeTable TSetHeat(table=[0,273.15 + 20.0; 120,273.15 + 20.0; 120,273.15 + 60.0; 500,273.15 + 60.0; 500,273.15 + 30.0; 1200,273.15 + 30.0]) "Setpoint heating"; Buildings.Fluid.Interfaces.PrescribedOutletState cooLimPow( redeclare package Medium = Medium, Q_flow_maxCool=-1000, m_flow_small=1E-4*abs(m_flow_nominal), show_T=true, m_flow_nominal=m_flow_nominal) "Steady-state model of the cooler with limited capacity"; Modelica.Blocks.Sources.TimeTable TSetCool(table=[0,273.15 + 20.0; 120,273.15 + 20.0; 120,273.15 + 15.0; 500,273.15 + 15.0; 500,273.15 + 10.0; 1200,273.15 + 10.0]) "Setpoint cooling"; Buildings.Fluid.Interfaces.PrescribedOutletState heaCooUnl( redeclare package Medium = Medium, m_flow_small=1E-4*abs(m_flow_nominal), show_T=true, m_flow_nominal=m_flow_nominal) "Steady-state model of the heater or cooler with unlimited capacity"; Modelica.Blocks.Sources.TimeTable TSetCoolHeat(table=[0,273.15 + 20.0; 120,273.15 + 20.0; 120,273.15 + 15.0; 500,273.15 + 15.0; 500,273.15 + 30.0; 1200,273.15 + 30.0]) "Setpoint cooling"; Modelica.Blocks.Sources.Ramp m_flow( height=-2*m_flow_nominal, duration=100, offset=m_flow_nominal, startTime=1000) "Mass flow rate"; Buildings.Fluid.Sources.MassFlowSource_T sou1( redeclare package Medium = Medium, use_m_flow_in=true, T=293.15, nPorts=1) "Flow source"; Buildings.Fluid.Sources.MassFlowSource_T sou2( redeclare package Medium = Medium, use_m_flow_in=true, T=293.15, nPorts=1) "Flow source"; Buildings.Fluid.Sources.MassFlowSource_T sou3( redeclare package Medium = Medium, use_m_flow_in=true, T=293.15, nPorts=1) "Flow source"; equation connect(TSetHeat.y,heaHigPow. TSet); connect(TSetCool.y,cooLimPow. TSet); connect(TSetCoolHeat.y,heaCooUnl. TSet); connect(m_flow.y, sou1.m_flow_in); connect(m_flow.y, sou2.m_flow_in); connect(m_flow.y, sou3.m_flow_in); connect(sou1.ports[1], heaHigPow.port_a); connect(sou2.ports[1], cooLimPow.port_a); connect(sou3.ports[1], heaCooUnl.port_a); connect(heaCooUnl.port_b, sin.ports[1]); connect(cooLimPow.port_b, sin.ports[2]); connect(heaHigPow.port_b, sin.ports[3]); end PrescribedOutletState;

Buildings.Fluid.Interfaces.Examples.ReverseFlowHumidifier Buildings.Fluid.Interfaces.Examples.ReverseFlowHumidifier

Model that tests the reverse flow for a humidifier

Buildings.Fluid.Interfaces.Examples.ReverseFlowHumidifier

Information

This model tests whether the results for a humidifer are identical for forward flow and reverse flow. If the results differ, then an assert is triggered.

Extends from Modelica.Icons.Example (Icon for runnable examples).

Modelica definition

model ReverseFlowHumidifier "Model that tests the reverse flow for a humidifier" extends Modelica.Icons.Example; package Medium = Buildings.Media.Air; Buildings.Utilities.Diagnostics.AssertEquality assTem(threShold=0.01) "Assert to test if the outputs of the forward flow and reverse flow model are identical"; Buildings.Utilities.Diagnostics.AssertEquality assEnt(threShold=0.5) "Assert to test if the outputs of the forward flow and reverse flow model are identical"; Buildings.Utilities.Diagnostics.AssertEquality assMas(threShold=1E-5) "Assert to test if the outputs of the forward flow and reverse flow model are identical"; Buildings.Fluid.MassExchangers.Humidifier_u humBac( redeclare package Medium = Medium, dp_nominal=0, m_flow(start=1), m_flow_nominal=1, mWat_flow_nominal=0.1, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial, T=283.15) "Humidifier with backward flow"; Buildings.Fluid.MassExchangers.Humidifier_u humFor( redeclare package Medium = Medium, dp_nominal=0, m_flow(start=1), m_flow_nominal=1, mWat_flow_nominal=0.1, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial, T=283.15) "Humidifier with forward flow"; Modelica.Blocks.Sources.Constant u2(k=0.01) "Control input"; Modelica.Fluid.Sources.MassFlowSource_T source1( redeclare package Medium = Medium, use_m_flow_in=false, use_T_in=false, use_X_in=false, T(displayUnit="K") = 323.15, X={0.01,0.99}, nPorts=1, m_flow=0.5) "Fluid source"; Buildings.Fluid.Sources.FixedBoundary sink1( redeclare package Medium = Medium, nPorts=2) "Fluid sink"; Sensors.SpecificEnthalpy senEnt1(redeclare package Medium = Medium) "Specific enthalpy sensor"; Sensors.Temperature senTem1(redeclare package Medium = Medium) "Temperature sensor"; Sensors.MassFraction senMas1(redeclare package Medium = Medium) "Mass fraction sensor"; Sensors.Temperature senTem2(redeclare package Medium = Medium) "Temperature sensor"; Sensors.SpecificEnthalpy senEnt2(redeclare package Medium = Medium) "Specific enthalpy sensor"; Sensors.MassFraction senMas2(redeclare package Medium = Medium) "Mass fraction sensor"; FixedResistances.FixedResistanceDpM res1( redeclare package Medium = Medium, m_flow_nominal=1, from_dp=true, linearized=false, dp_nominal=1000) "Fixed resistance"; FixedResistances.FixedResistanceDpM res2( redeclare package Medium = Medium, m_flow_nominal=1, from_dp=true, linearized=false, dp_nominal=1000) "Fixed resistance"; Modelica.Fluid.Sources.MassFlowSource_T source2( redeclare package Medium = Medium, use_m_flow_in=false, use_T_in=false, use_X_in=false, T(displayUnit="K") = 323.15, X={0.01,0.99}, nPorts=1, m_flow=0.5) "Fluid source"; equation connect(u2.y, humFor.u); connect(u2.y, humBac.u); connect(humFor.port_b, senTem1.port); connect(humFor.port_b, senEnt1.port); connect(humFor.port_b, senMas1.port); connect(humBac.port_a, senTem2.port); connect(humBac.port_a, senEnt2.port); connect(humBac.port_a, senMas2.port); connect(humFor.port_b, res1.port_a); connect(res1.port_b, sink1.ports[1]); connect(humBac.port_a, res2.port_a); connect(res2.port_b, sink1.ports[2]); connect(senTem1.T, assTem.u1); connect(senEnt1.h_out, assEnt.u1); connect(senMas1.X, assMas.u1); connect(senTem2.T, assTem.u2); connect(senEnt2.h_out, assEnt.u2); connect(senMas2.X, assMas.u2); connect(humFor.port_a, source1.ports[1]); connect(source2.ports[1], humBac.port_b); end ReverseFlowHumidifier;

Buildings.Fluid.Interfaces.Examples.ReverseFlowMassExchanger Buildings.Fluid.Interfaces.Examples.ReverseFlowMassExchanger

Model that tests the reverse flow for a mass exchanger

Buildings.Fluid.Interfaces.Examples.ReverseFlowMassExchanger

Information

This model tests whether the results for a mass exchanger are identical for forward flow and reverse flow. If the results differ, then an assert is triggered.

Note that if the latent heat transfer effectiveness is non-zero, then the results will differ. The reason is that the maximum capacity stream is computed using the mass flow rates at port_a1 and port_a2. For reverse flow, they are not equal if moisture is added to the mass flow rate. Using an average mass flow rate in computing the heat and moisture transfer would lead to identical results, but it would introduce additional nonlinear equations that need to be solved. Therefore, the model uses the mass flow rates at port_a1 and port_a2.

Note: This problem fails to translate in Dymola 2012 due to an error in Dymola's support of stream connector. This bug will be corrected in future versions of Dymola.

Extends from Modelica.Icons.Example (Icon for runnable examples).

Modelica definition

model ReverseFlowMassExchanger "Model that tests the reverse flow for a mass exchanger" extends Modelica.Icons.Example; package Medium = Buildings.Media.Air; Buildings.Utilities.Diagnostics.AssertEquality assTem(threShold=1E-8, startTime=0) "Assert to test if the outputs of the forward flow and reverse flow model are identical"; Buildings.Utilities.Diagnostics.AssertEquality assEnt(threShold=1E-8, startTime=0) "Assert to test if the outputs of the forward flow and reverse flow model are identical"; Buildings.Utilities.Diagnostics.AssertEquality assMas(threShold=1E-8, startTime=0) "Assert to test if the outputs of the forward flow and reverse flow model are identical"; Modelica.Fluid.Sources.MassFlowSource_T source2( m_flow=1, redeclare package Medium = Medium, use_m_flow_in=false, use_T_in=false, use_X_in=false, nPorts=1, T(displayUnit="degC") = 303.15, X={0.02,0.98}); Buildings.Fluid.MassExchangers.ConstantEffectiveness masExcFor( redeclare package Medium1 = Medium, redeclare package Medium2 = Medium, m1_flow_nominal=1, m2_flow_nominal=1, dp1_nominal=0, dp2_nominal=0, epsL=0) "Mass exchanger with forward flow"; Buildings.Fluid.MassExchangers.ConstantEffectiveness masExcRev( redeclare package Medium1 = Medium, redeclare package Medium2 = Medium, m1_flow_nominal=1, m2_flow_nominal=1, dp1_nominal=0, dp2_nominal=0, epsL=0) "Mass exchanger with reverse flow"; Buildings.Fluid.Sources.FixedBoundary sink2( redeclare package Medium = Medium, nPorts=2) "Fluid sink"; FixedResistances.FixedResistanceDpM res3( redeclare package Medium = Medium, m_flow_nominal=1, from_dp=true, linearized=false, dp_nominal=1000) "Fixed resistance"; FixedResistances.FixedResistanceDpM res4( redeclare package Medium = Medium, m_flow_nominal=1, from_dp=true, linearized=false, dp_nominal=1000) "Fixed resistance"; Sensors.SpecificEnthalpy senEnt3(redeclare package Medium = Medium); Sensors.Temperature senTem3(redeclare package Medium = Medium); Sensors.MassFraction senMas3(redeclare package Medium = Medium); Sensors.SpecificEnthalpy senEnt4(redeclare package Medium = Medium); Sensors.Temperature senTem4(redeclare package Medium = Medium); Sensors.MassFraction senMas4(redeclare package Medium = Medium); Buildings.Utilities.Diagnostics.AssertEquality assTem1(threShold=1E-8, startTime=0) "Assert to test if the outputs of the forward flow and reverse flow model are identical"; Buildings.Utilities.Diagnostics.AssertEquality assEnt1(threShold=1E-8, startTime=0) "Assert to test if the outputs of the forward flow and reverse flow model are identical"; Buildings.Utilities.Diagnostics.AssertEquality assMas1(threShold=1E-8, startTime=0) "Assert to test if the outputs of the forward flow and reverse flow model are identical"; Modelica.Fluid.Sources.MassFlowSource_T source3( m_flow=1, redeclare package Medium = Medium, use_m_flow_in=false, use_T_in=false, use_X_in=false, X={0.01,0.99}, nPorts=1, T(displayUnit="degC") = 293.15); Modelica.Fluid.Sources.MassFlowSource_T source4( m_flow=1, redeclare package Medium = Medium, use_m_flow_in=false, use_T_in=false, use_X_in=false, nPorts=1, T(displayUnit="degC") = 303.15, X={0.02,0.98}); Modelica.Fluid.Sources.MassFlowSource_T source1( m_flow=1, redeclare package Medium = Medium, use_m_flow_in=false, use_T_in=false, use_X_in=false, X={0.01,0.99}, nPorts=1, T(displayUnit="degC") = 293.15); Buildings.Fluid.Sources.FixedBoundary sink1( redeclare package Medium = Medium, nPorts=2) "Fluid sink"; Sensors.SpecificEnthalpy senEnt1(redeclare package Medium = Medium); Sensors.Temperature senTem1(redeclare package Medium = Medium); Sensors.MassFraction senMas1(redeclare package Medium = Medium); Sensors.Temperature senTem2(redeclare package Medium = Medium); Sensors.SpecificEnthalpy senEnt2(redeclare package Medium = Medium); Sensors.MassFraction senMas2(redeclare package Medium = Medium); FixedResistances.FixedResistanceDpM res1( redeclare package Medium = Medium, m_flow_nominal=1, from_dp=true, linearized=false, dp_nominal=1000) "Fixed resistance"; FixedResistances.FixedResistanceDpM res2( redeclare package Medium = Medium, m_flow_nominal=1, from_dp=true, linearized=false, dp_nominal=1000) "Fixed resistance"; equation connect(res1.port_b, sink1.ports[1]); connect(res2.port_b, sink1.ports[2]); connect(senTem1.T, assTem.u1); connect(senEnt1.h_out, assEnt.u1); connect(senMas1.X, assMas.u1); connect(senTem2.T, assTem.u2); connect(senEnt2.h_out, assEnt.u2); connect(senMas2.X, assMas.u2); connect(masExcFor.port_b1, res1.port_a); connect(masExcFor.port_a1, source1.ports[1]); connect(masExcRev.port_a1, res2.port_a); connect(source2.ports[1], masExcFor.port_a2); connect(masExcRev.port_a1, senTem2.port); connect(masExcRev.port_a1, senEnt2.port); connect(masExcRev.port_a1, senMas2.port); connect(masExcFor.port_b1, senTem1.port); connect(masExcFor.port_b1, senEnt1.port); connect(masExcFor.port_b1, senMas1.port); connect(masExcFor.port_b2, res3.port_a); connect(masExcRev.port_a2, res4.port_a); connect(res3.port_b, sink2.ports[1]); connect(res4.port_b, sink2.ports[2]); connect(senTem3.T, assTem1.u1); connect(senTem4.T, assTem1.u2); connect(senEnt3.h_out, assEnt1.u1); connect(senEnt4.h_out, assEnt1.u2); connect(senMas3.X, assMas1.u1); connect(senMas4.X, assMas1.u2); connect(masExcFor.port_b2, senTem3.port); connect(masExcFor.port_b2, senEnt3.port); connect(masExcFor.port_b2, senMas3.port); connect(masExcRev.port_a2, senTem4.port); connect(masExcRev.port_a2, senEnt4.port); connect(masExcRev.port_a2, senMas4.port); connect(source3.ports[1], masExcRev.port_b1); connect(source4.ports[1], masExcRev.port_b2); end ReverseFlowMassExchanger;

Buildings.Fluid.Interfaces.Examples.StaticTwoPortConservationEquation Buildings.Fluid.Interfaces.Examples.StaticTwoPortConservationEquation

Model that tests the static two port conservation equation

Buildings.Fluid.Interfaces.Examples.StaticTwoPortConservationEquation

Information

Model that tests the conservation equations that are used for the heat and mass balance. The instances have either water or air, and either allow or prohibit flow reversal. This example tests the implementation of the steady-state balance.

Extends from Modelica.Icons.Example (Icon for runnable examples).

Modelica definition

model StaticTwoPortConservationEquation "Model that tests the static two port conservation equation" extends Modelica.Icons.Example; package MediumW = Buildings.Media.Water "Medium model"; package MediumA = Buildings.Media.Air "Medium model"; Modelica.Blocks.Sources.Constant mWat_flow(k=0) "Water mass flow rate added to the control volume"; Modelica.Blocks.Sources.TimeTable QSen_flow(startTime=0, table=[ 0,-100; 900,-100; 900,0; 1800,0; 1800,100]) "Sensible heat flow rate added to the control volume"; SubModel modWatRev( redeclare package Medium = MediumW, allowFlowReversal=true, use_mWat_flow = false) "Submodel for energy and mass balance"; SubModel modWatNoRev( redeclare package Medium = MediumW, allowFlowReversal=false, use_mWat_flow = false) "Submodel for energy and mass balance"; SubModel modAirRev( redeclare package Medium = MediumA, allowFlowReversal=true, use_mWat_flow = true) "Submodel for energy and mass balance"; SubModel modAirNoRev( redeclare package Medium = MediumA, allowFlowReversal=false, use_mWat_flow = true) "Submodel for energy and mass balance"; equation connect(QSen_flow.y, modWatRev.Q_flow); connect(mWat_flow.y, modWatRev.mWat_flow); protected model SubModel replaceable package Medium = Modelica.Media.Interfaces.PartialMedium "Medium model"; Sources.MassFlowSource_T bou( nPorts=1, redeclare package Medium = Medium, m_flow=0.01) "Boundary condition for mass flow rate"; Buildings.Fluid.Interfaces.StaticTwoPortConservationEquation conEqn( redeclare package Medium = Medium, m_flow_nominal=0.01, show_T=true, allowFlowReversal=allowFlowReversal, use_mWat_flow=use_mWat_flow, prescribedHeatFlowRate=true) "Steady-state conservation equation"; Buildings.Fluid.Sources.Boundary_pT sin( use_p_in=false, redeclare package Medium = Medium, nPorts=1, p=101325, T=283.15) "Sink"; Modelica.Blocks.Interfaces.RealInput Q_flow(unit="W"); Modelica.Blocks.Interfaces.RealInput mWat_flow(unit="kg/s"); parameter Boolean use_mWat_flow "Set to true to enable exchange of moisture"; parameter Boolean allowFlowReversal=true "= true to allow flow reversal, false restricts to design direction (port_a -> port_b)"; equation connect(conEqn.port_b, sin.ports[1]); connect(conEqn.port_a, bou.ports[1]); connect(Q_flow, conEqn.Q_flow); connect(mWat_flow, conEqn.mWat_flow); end SubModel; equation connect(QSen_flow.y, modWatNoRev.Q_flow); connect(mWat_flow.y, modWatNoRev.mWat_flow); connect(QSen_flow.y, modAirRev.Q_flow); connect(mWat_flow.y, modAirRev.mWat_flow); connect(QSen_flow.y, modAirNoRev.Q_flow); connect(mWat_flow.y, modAirNoRev.mWat_flow); end StaticTwoPortConservationEquation;

Buildings.Fluid.Interfaces.Examples.Humidifier_u.Humidifier Buildings.Fluid.Interfaces.Examples.Humidifier_u.Humidifier

Model for humidifier that adds a variable for the thermodynamic states at its ports

Buildings.Fluid.Interfaces.Examples.Humidifier_u.Humidifier

Information

Extends from Buildings.Fluid.MassExchangers.Humidifier_u (Ideal humidifier or dehumidifier with prescribed water mass flow rate addition or subtraction).

Parameters

TypeNameDefaultDescription
replaceable package MediumPartialCondensingGasesMedium in the component
Booleanuse_T_infalseGet the temperature from the input connector
TemperatureT293.15Temperature of water that is added to the fluid stream (used if use_T_in=false) [K]
MassFlowRatemWat_flow_nominal Water mass flow rate at u=1, positive for humidification [kg/s]
Nominal condition
MassFlowRatem_flow_nominal Nominal mass flow rate [kg/s]
PressureDifferencedp_nominal Pressure difference [Pa]
Initialization
MassFlowRatem_flow.start0Mass flow rate from port_a to port_b (m_flow > 0 is design flow direction) [kg/s]
PressureDifferencedp.start0Pressure difference between port_a and port_b [Pa]
Assumptions
BooleanallowFlowReversaltrue= true to allow flow reversal, false restricts to design direction (port_a -> port_b)
Advanced
MassFlowRatem_flow_small1E-4*abs(m_flow_nominal)Small mass flow rate for regularization of zero flow [kg/s]
BooleanhomotopyInitializationtrue= true, use homotopy method
Diagnostics
Booleanshow_Tfalse= true, if actual temperature at port is computed
Flow resistance
Booleanfrom_dpfalse= true, use m_flow = f(dp) else dp = f(m_flow)
BooleanlinearizeFlowResistancefalse= true, use linear relation between m_flow and dp for any flow rate
RealdeltaM0.1Fraction of nominal flow rate where flow transitions to laminar
Dynamics
Nominal condition
Timetau30Time constant at nominal flow (if energyDynamics <> SteadyState) [s]
Equations
DynamicsenergyDynamicsModelica.Fluid.Types.Dynamic...Type of energy balance: dynamic (3 initialization options) or steady state
DynamicsmassDynamicsenergyDynamicsType of mass balance: dynamic (3 initialization options) or steady state
Initialization
AbsolutePressurep_startMedium.p_defaultStart value of pressure [Pa]
TemperatureT_startMedium.T_defaultStart value of temperature [K]
MassFractionX_start[Medium.nX]Medium.X_defaultStart value of mass fractions m_i/m [kg/kg]
ExtraPropertyC_start[Medium.nC]fill(0, Medium.nC)Start value of trace substances

Connectors

TypeNameDescription
FluidPort_aport_aFluid connector a (positive design flow direction is from port_a to port_b)
FluidPort_bport_bFluid connector b (positive design flow direction is from port_a to port_b)
input RealInputT_inTemperature of water added to the fluid stream
input RealInputuControl input

Modelica definition

model Humidifier "Model for humidifier that adds a variable for the thermodynamic states at its ports" extends Buildings.Fluid.MassExchangers.Humidifier_u; Medium.ThermodynamicState staA= Medium.setState_phX(port_a.p, actualStream(port_a.h_outflow), actualStream(port_a.Xi_outflow)) "Thermodynamic state in port a"; Medium.ThermodynamicState staB= Medium.setState_phX(port_b.p, actualStream(port_b.h_outflow), actualStream(port_b.Xi_outflow)) "Thermodynamic state in port b"; end Humidifier;

Buildings.Fluid.Interfaces.Examples.StaticTwoPortConservationEquation.SubModel Buildings.Fluid.Interfaces.Examples.StaticTwoPortConservationEquation.SubModel


Buildings.Fluid.Interfaces.Examples.StaticTwoPortConservationEquation.SubModel

Parameters

TypeNameDefaultDescription
replaceable package MediumModelica.Media.Interfaces.Pa...Medium model
Booleanuse_mWat_flow Set to true to enable exchange of moisture
BooleanallowFlowReversaltrue= true to allow flow reversal, false restricts to design direction (port_a -> port_b)

Connectors

TypeNameDescription
replaceable package MediumMedium model
input RealInputQ_flow[W]
input RealInputmWat_flow[kg/s]

Modelica definition

model SubModel replaceable package Medium = Modelica.Media.Interfaces.PartialMedium "Medium model"; Sources.MassFlowSource_T bou( nPorts=1, redeclare package Medium = Medium, m_flow=0.01) "Boundary condition for mass flow rate"; Buildings.Fluid.Interfaces.StaticTwoPortConservationEquation conEqn( redeclare package Medium = Medium, m_flow_nominal=0.01, show_T=true, allowFlowReversal=allowFlowReversal, use_mWat_flow=use_mWat_flow, prescribedHeatFlowRate=true) "Steady-state conservation equation"; Buildings.Fluid.Sources.Boundary_pT sin( use_p_in=false, redeclare package Medium = Medium, nPorts=1, p=101325, T=283.15) "Sink"; Modelica.Blocks.Interfaces.RealInput Q_flow(unit="W"); Modelica.Blocks.Interfaces.RealInput mWat_flow(unit="kg/s"); parameter Boolean use_mWat_flow "Set to true to enable exchange of moisture"; parameter Boolean allowFlowReversal=true "= true to allow flow reversal, false restricts to design direction (port_a -> port_b)"; equation connect(conEqn.port_b, sin.ports[1]); connect(conEqn.port_a, bou.ports[1]); connect(Q_flow, conEqn.Q_flow); connect(mWat_flow, conEqn.mWat_flow); end SubModel;
http://simulationresearch.lbl.gov/modelica