model To_VolumeFraction "Example problem for conversion model" extends Modelica.Icons.Example; package Medium = Buildings.Media.GasesPTDecoupled.SimpleAir(extraPropertiesNames={"CO2"}); Buildings.Fluid.Sensors.Conversions.To_VolumeFraction conMasVolFra(MMMea= Modelica.Media.IdealGases.Common.SingleGasesData.CO2.MM) "Conversion from mass fraction CO2 to volume fraction CO2"; Modelica.Blocks.Sources.Constant volFra(k=1000E-6) "Set point for volume fraction of 700PPM CO2"; Buildings.Controls.Continuous.LimPID limPID( controllerType=Modelica.Blocks.Types.SimpleController.PI, reverseAction=true, Ti=600, k=2, Td=1); Buildings.Fluid.Sensors.TraceSubstances senCO2(redeclare package Medium = Medium, substanceName="CO2") "CO2 sensor"; Buildings.Fluid.MixingVolumes.MixingVolume vol( nPorts=4, redeclare package Medium = Medium, V=4*4*2.7, C_start={300E-6}*44.009544/28.9651159, m_flow_nominal=0.1, energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial) "Volume of air"; Buildings.Fluid.Sources.TraceSubstancesFlowSource souCO2( use_m_flow_in=true, redeclare package Medium = Medium, nPorts=1) "CO2 source"; Modelica.Blocks.Math.Gain CO2Per(k=15/1000/3600*1.977) "CO2 emission per person"; Buildings.Fluid.Sources.MassFlowSource_T sou( use_m_flow_in=true, redeclare package Medium = Medium, C={300E-6}*44.009544/28.9651159, nPorts=1) "Source of fresh air with 300 PPM CO2"; Buildings.Fluid.Sources.FixedBoundary sin( redeclare package Medium = Medium, p=100000, C={300E-6}*44.009544/28.9651159, nPorts=1) "Sink for exhaust air"; Modelica.Blocks.Math.Gain gai(k=50/3600) "Gain for mass flow rate"; Modelica.Blocks.Sources.Constant nPeo(k=1) "Number of people"; Buildings.Fluid.Sensors.VolumeFlowRate senVolFlo(redeclare package Medium = Medium, m_flow_nominal=0.1); Modelica.Blocks.Math.Gain norSet(k=1/1000E-6) "Normalization for set point (to scale control input)"; Modelica.Blocks.Math.Gain norMea(k=1/1000E-6) "Normalization for measured concentration (to scale control input)"; Modelica.Blocks.Math.Gain conVolFlo(k=3600, y(unit="m3/h")) "Conversion from m3/s to m3/h"; Buildings.Fluid.Sensors.TraceSubstancesTwoPort senTraSubPeo(m_flow_nominal=0.1, redeclare package Medium = Medium, C_start=0, initType=Modelica.Blocks.Types.Init.InitialState) "CO2 concentration in absorptance from people"; Buildings.Fluid.Sensors.TraceSubstancesTwoPort senTraSubFre(m_flow_nominal=0.1, redeclare package Medium = Medium, C_start=0, initType=Modelica.Blocks.Types.Init.InitialState) "CO2 concentration in fresh air supply"; inner Modelica.Fluid.System system; Buildings.Fluid.FixedResistances.FixedResistanceDpM res( redeclare package Medium = Medium, dp_nominal=10, m_flow_nominal=50/3600) "Pressure drop to decouple the state of the volume from the state of the boundary condition"; equation connect(souCO2.m_flow_in, CO2Per.y); connect(gai.y, sou.m_flow_in); connect(limPID.y, gai.u); connect(nPeo.y, CO2Per.u); connect(sou.ports[1], senVolFlo.port_a); connect(senCO2.C, conMasVolFra.m); connect(conMasVolFra.V, norMea.u); connect(norMea.y, limPID.u_m); connect(volFra.y, norSet.u); connect(norSet.y, limPID.u_s); connect(conVolFlo.u, senVolFlo.V_flow); connect(souCO2.ports[1], senTraSubPeo.port_a); connect(senTraSubPeo.port_b, vol.ports[1]); connect(senVolFlo.port_b, senTraSubFre.port_a); connect(senTraSubFre.port_b, vol.ports[2]); connect(vol.ports[3], senCO2.port); connect(vol.ports[4], res.port_a); connect(res.port_b, sin.ports[1]); end To_VolumeFraction;