block ActuatorFilter "Filter used for actuators of valves, dampers and movers" import Modelica.Blocks.Types.Init; extends Modelica.Blocks.Interfaces.SISO; constant Integer n=2 "Order of filter"; parameter Modelica.Units.SI.Frequency f(start=1) "Cut-off frequency"; parameter Boolean normalized = true "= true, if amplitude at f_cut is 3 dB, otherwise unmodified filter"; parameter Modelica.Blocks.Types.Init initType=Modelica.Blocks.Types.Init.NoInit "Type of initialization (1: no init, 2: steady state, 3: initial state, 4: initial output)"; parameter Real x_start[n]=zeros(n) "Initial or guess values of states"; parameter Real y_start=0.0 "Initial value of output (remaining states are in steady state)"; parameter Real u_nominal = 1 "Magnitude of input"; Real x[n](each final stateSelect=StateSelect.never) = u_nom*s "Transformed filter states"; protected final parameter Real u_nom = if abs(u_nominal-1) < 1E-12 then 1-1E-12 else u_nominal "Magnitude of input (set to a value different from 1 to avoid elimination by symbolic processing)"; parameter Real alpha=if normalized then sqrt(2^(1/n) - 1) else 1.0 "Frequency correction factor for normalized filter"; parameter Real w_u=2*Modelica.Constants.pi*f/alpha/u_nom; Real s[n](start=x_start/u_nom) "Filter states"; initial equation if initType == Init.SteadyState then der(s) = zeros(n); elseif initType == Init.InitialState then s = x_start/u_nom; elseif initType == Init.InitialOutput then y = y_start; der(s[1:n - 1]) = zeros(n - 1); end if; equation der(s[1]) = (u - u_nom*s[1])*w_u; for i in 2:n loop der(s[i]) = (u_nom*s[i - 1] - u_nom*s[i])*w_u; end for; y =u_nom*s[n]; end ActuatorFilter;

block IndexMassFraction "Computes the index of a substance in the mass fraction vector Xi" replaceable package Medium = Modelica.Media.Interfaces.PartialCondensingGases "Medium model"; parameter String substanceName="" "Name of species substance"; protected parameter Integer i_x = sum( if Modelica.Utilities.Strings.isEqual(string1=Medium.substanceNames[i], string2=substanceName, caseSensitive=false) then i else 0 for i in 1:Medium.nXi) "Index of substance"; initial equation assert(i_x > 0, "Substance '" + substanceName + "' is not present in medium '" + Medium.mediumName + "'.\n" + "Change medium model to one that has '" + substanceName + "' as a substance."); end IndexMassFraction;

model MassFlowRateMultiplier "Model that multiplies the mass flow rate" extends Buildings.Fluid.Interfaces.PartialTwoPort; parameter Boolean use_input=false "Set to true for multiplier factor provided as an input instead of a parameter"; parameter Real k=1 "Gain for mass flow rate"; Modelica.Blocks.Interfaces.RealInput u( final unit="1", final min=Modelica.Constants.small) if use_input "Multiplier factor"; Modelica.Blocks.Interfaces.RealOutput uInv if use_input "Inverse of the multiplier factor"; protected Modelica.Blocks.Interfaces.RealInput u_internal "Connector for multiplier factor for internal use only"; Modelica.Blocks.Sources.Constant cst( final k=k) if not use_input "Constant gain value"; Modelica.Blocks.Math.Division div1 if use_input "Compute the inverse"; Modelica.Blocks.Sources.Constant one( final k=1) if use_input "Constant 1"; initial equation assert(k > Modelica.Constants.small, "Gain must be strictly positive. Received k = " + String(k)); equation assert(u_internal > Modelica.Constants.small, "Gain must be strictly positive. Received u = " + String(u_internal)); // Pressure drop in design flow direction port_a.p = port_b.p; // Mass balance (mass is not conserved by this model!) port_b.m_flow = -u_internal * port_a.m_flow; // Specific enthalpy flow rate port_a.h_outflow = inStream(port_b.h_outflow); port_b.h_outflow = inStream(port_a.h_outflow); // Transport of substances port_a.Xi_outflow = inStream(port_b.Xi_outflow); port_b.Xi_outflow = inStream(port_a.Xi_outflow); port_a.C_outflow = inStream(port_b.C_outflow); port_b.C_outflow = inStream(port_a.C_outflow); connect(cst.y, u_internal); connect(u_internal, div1.u2); connect(one.y, div1.u1); connect(div1.y, uInv); connect(u, u_internal); end MassFlowRateMultiplier;

partial model PartialResistance "Partial model for a hydraulic resistance" extends Buildings.Fluid.Interfaces.PartialTwoPortInterface( show_T=false, dp(nominal=if dp_nominal_pos > Modelica.Constants.eps then dp_nominal_pos else 1), m_flow( nominal=if m_flow_nominal_pos > Modelica.Constants.eps then m_flow_nominal_pos else 1), final m_flow_small = 1E-4*abs(m_flow_nominal)); constant Boolean homotopyInitialization = true "= true, use homotopy method"; parameter Boolean from_dp = false "= true, use m_flow = f(dp) else dp = f(m_flow)"; parameter Modelica.Units.SI.PressureDifference dp_nominal(displayUnit="Pa") "Pressure drop at nominal mass flow rate"; parameter Boolean linearized = false "= true, use linear relation between m_flow and dp for any flow rate"; parameter Modelica.Units.SI.MassFlowRate m_flow_turbulent(min=0) "Turbulent flow if |m_flow| >= m_flow_turbulent"; protected parameter Medium.ThermodynamicState sta_default= Medium.setState_pTX(T=Medium.T_default, p=Medium.p_default, X=Medium.X_default); parameter Modelica.Units.SI.DynamicViscosity eta_default= Medium.dynamicViscosity(sta_default) "Dynamic viscosity, used to compute transition to turbulent flow regime"; final parameter Modelica.Units.SI.MassFlowRate m_flow_nominal_pos=abs( m_flow_nominal) "Absolute value of nominal flow rate"; final parameter Modelica.Units.SI.PressureDifference dp_nominal_pos( displayUnit="Pa") = abs(dp_nominal) "Absolute value of nominal pressure difference"; initial equation assert(homotopyInitialization, "In " + getInstanceName() + ": The constant homotopyInitialization has been modified from its default value. This constant will be removed in future releases.", level = AssertionLevel.warning); equation // Isenthalpic state transformation (no storage and no loss of energy) port_a.h_outflow = if allowFlowReversal then inStream(port_b.h_outflow) else Medium.h_default; port_b.h_outflow = inStream(port_a.h_outflow); // Mass balance (no storage) port_a.m_flow + port_b.m_flow = 0; // Transport of substances port_a.Xi_outflow = if allowFlowReversal then inStream(port_b.Xi_outflow) else Medium.X_default[1:Medium.nXi]; port_b.Xi_outflow = inStream(port_a.Xi_outflow); port_a.C_outflow = if allowFlowReversal then inStream(port_b.C_outflow) else zeros(Medium.nC); port_b.C_outflow = inStream(port_a.C_outflow); end PartialResistance;

partial model PartialThreeWayResistance "Flow splitter with partial resistance model at each port" extends Buildings.Fluid.Interfaces.LumpedVolumeDeclarations( final massDynamics=energyDynamics, final mSenFac=1); Modelica.Fluid.Interfaces.FluidPort_a port_1( redeclare package Medium = Medium, h_outflow(start=Medium.h_default, nominal=Medium.h_default), m_flow(min=if (portFlowDirection_1 == Modelica.Fluid.Types.PortFlowDirection.Entering) then 0.0 else -Modelica.Constants.inf, max=if (portFlowDirection_1== Modelica.Fluid.Types.PortFlowDirection.Leaving) then 0.0 else Modelica.Constants.inf)) "First port, typically inlet"; Modelica.Fluid.Interfaces.FluidPort_b port_2( redeclare package Medium = Medium, h_outflow(start=Medium.h_default, nominal=Medium.h_default), m_flow(min=if (portFlowDirection_2 == Modelica.Fluid.Types.PortFlowDirection.Entering) then 0.0 else -Modelica.Constants.inf, max=if (portFlowDirection_2 == Modelica.Fluid.Types.PortFlowDirection.Leaving) then 0.0 else Modelica.Constants.inf)) "Second port, typically outlet"; Modelica.Fluid.Interfaces.FluidPort_a port_3( redeclare package Medium=Medium, h_outflow(start=Medium.h_default, nominal=Medium.h_default), m_flow(min=if (portFlowDirection_3==Modelica.Fluid.Types.PortFlowDirection.Entering) then 0.0 else -Modelica.Constants.inf, max=if (portFlowDirection_3==Modelica.Fluid.Types.PortFlowDirection.Leaving) then 0.0 else Modelica.Constants.inf)) "Third port, can be either inlet or outlet"; parameter Modelica.Units.SI.Time tau=10 "Time constant at nominal flow for dynamic energy and momentum balance"; parameter Modelica.Units.SI.MassFlowRate mDyn_flow_nominal "Nominal mass flow rate for dynamic momentum and energy balance"; parameter Boolean from_dp = true "= true, use m_flow = f(dp) else dp = f(m_flow)"; parameter Modelica.Fluid.Types.PortFlowDirection portFlowDirection_1=Modelica.Fluid.Types.PortFlowDirection.Bidirectional "Flow direction for port_1"; parameter Modelica.Fluid.Types.PortFlowDirection portFlowDirection_2=Modelica.Fluid.Types.PortFlowDirection.Bidirectional "Flow direction for port_2"; parameter Modelica.Fluid.Types.PortFlowDirection portFlowDirection_3=Modelica.Fluid.Types.PortFlowDirection.Bidirectional "Flow direction for port_3"; parameter Boolean verifyFlowReversal = false "=true, to assert that the flow does not reverse when portFlowDirection_* does not equal Bidirectional"; parameter Modelica.Units.SI.MassFlowRate m_flow_small "Small mass flow rate for checking flow reversal"; replaceable Buildings.Fluid.Interfaces.PartialTwoPortInterface res1 constrainedby Buildings.Fluid.Interfaces.PartialTwoPortInterface( redeclare final package Medium = Medium, allowFlowReversal=portFlowDirection_1 == Modelica.Fluid.Types.PortFlowDirection.Bidirectional) "Partial model, to be replaced with a fluid component"; replaceable Buildings.Fluid.Interfaces.PartialTwoPortInterface res2 constrainedby Buildings.Fluid.Interfaces.PartialTwoPortInterface( redeclare final package Medium = Medium, allowFlowReversal=portFlowDirection_2 == Modelica.Fluid.Types.PortFlowDirection.Bidirectional) "Partial model, to be replaced with a fluid component"; replaceable Buildings.Fluid.Interfaces.PartialTwoPortInterface res3 constrainedby Buildings.Fluid.Interfaces.PartialTwoPortInterface( redeclare final package Medium = Medium, allowFlowReversal=portFlowDirection_3 == Modelica.Fluid.Types.PortFlowDirection.Bidirectional) "Partial model, to be replaced with a fluid component"; Buildings.Fluid.Delays.DelayFirstOrder vol( redeclare final package Medium = Medium, final nPorts=3, final tau=tau, final m_flow_nominal=mDyn_flow_nominal, final energyDynamics=energyDynamics, final p_start=p_start, final T_start=T_start, final X_start=X_start, final C_start=C_start, final allowFlowReversal=true, final prescribedHeatFlowRate=false) if have_controlVolume "Fluid volume to break algebraic loop"; protected parameter Boolean have_controlVolume= energyDynamics <> Modelica.Fluid.Types.Dynamics.SteadyState "Boolean flag used to remove conditional components"; Modelica.Fluid.Interfaces.FluidPort_a port_internal( redeclare package Medium = Medium) if not have_controlVolume "Internal dummy port for easier connection of conditional connections"; initial equation assert(portFlowDirection_1<>Modelica.Fluid.Types.PortFlowDirection.Leaving or portFlowDirection_2<>Modelica.Fluid.Types.PortFlowDirection.Leaving or portFlowDirection_3<>Modelica.Fluid.Types.PortFlowDirection.Leaving, "In " + getInstanceName() + ": All ports are configured to Modelica.Fluid.Types.PortFlowDirection.Leaving, which is non-physical."); assert(portFlowDirection_1<>Modelica.Fluid.Types.PortFlowDirection.Entering or portFlowDirection_2<>Modelica.Fluid.Types.PortFlowDirection.Entering or portFlowDirection_3<>Modelica.Fluid.Types.PortFlowDirection.Entering, "In " + getInstanceName() + ": All ports are configured to Modelica.Fluid.Types.PortFlowDirection.Entering, which is non-physical."); equation if verifyFlowReversal then if portFlowDirection_1==Modelica.Fluid.Types.PortFlowDirection.Entering then assert(port_1.m_flow> -m_flow_small, "In " + getInstanceName() + ": Flow is leaving port_1 despite portFlowDirection_1=PortFlowDirection.Entering, since m_flow=" + String(port_1.m_flow) + "<-"+String(m_flow_small)); end if; if portFlowDirection_1==Modelica.Fluid.Types.PortFlowDirection.Leaving then assert(port_1.m_flow< m_flow_small, "In " + getInstanceName() + ": Flow is entering port_1 despite portFlowDirection_1=PortFlowDirection.Leaving, since m_flow=" + String(port_1.m_flow) + ">"+String(m_flow_small)); end if; if portFlowDirection_2==Modelica.Fluid.Types.PortFlowDirection.Entering then assert(port_2.m_flow> -m_flow_small, "In " + getInstanceName() + ": Flow is leaving port_2 despite portFlowDirection_2=PortFlowDirection.Entering, since m_flow=" + String(port_2.m_flow) + "<-"+String(m_flow_small)); end if; if portFlowDirection_2==Modelica.Fluid.Types.PortFlowDirection.Leaving then assert(port_2.m_flow< m_flow_small, "In " + getInstanceName() + ": Flow is entering port_2 despite portFlowDirection_2=PortFlowDirection.Leaving, since m_flow=" + String(port_2.m_flow) + ">"+String(m_flow_small)); end if; if portFlowDirection_3==Modelica.Fluid.Types.PortFlowDirection.Entering then assert(port_3.m_flow> -m_flow_small, "In " + getInstanceName() + ": Flow is leaving port_3 despite portFlowDirection_3=PortFlowDirection.Entering, since m_flow=" + String(port_3.m_flow) + "<-"+String(m_flow_small)); end if; if portFlowDirection_3==Modelica.Fluid.Types.PortFlowDirection.Leaving then assert(port_3.m_flow< m_flow_small, "In " + getInstanceName() + ": Flow is entering port_3 despite portFlowDirection_3=PortFlowDirection.Leaving, since m_flow=" + String(port_3.m_flow) + ">"+String(m_flow_small)); end if; end if; if portFlowDirection_1==Modelica.Fluid.Types.PortFlowDirection.Leaving then if not have_controlVolume then connect(res1.port_a, port_internal); else connect(res1.port_a, vol.ports[1]); end if; connect(port_1, res1.port_b); else if not have_controlVolume then connect(res1.port_b, port_internal); else connect(res1.port_b, vol.ports[1]); end if; connect(port_1, res1.port_a); end if; if portFlowDirection_2==Modelica.Fluid.Types.PortFlowDirection.Leaving then if not have_controlVolume then connect(res2.port_a, port_internal); else connect(res2.port_a, vol.ports[2]); end if; connect(port_2, res2.port_b); else if not have_controlVolume then connect(res2.port_b, port_internal); else connect(res2.port_b, vol.ports[2]); end if; connect(port_2, res2.port_a); end if; if portFlowDirection_3==Modelica.Fluid.Types.PortFlowDirection.Leaving then if not have_controlVolume then connect(res3.port_a, port_internal); else connect(res3.port_a, vol.ports[3]); end if; connect(port_3, res3.port_b); else if not have_controlVolume then connect(res3.port_b, port_internal); else connect(res3.port_b, vol.ports[3]); end if; connect(port_3, res3.port_a); end if; end PartialThreeWayResistance;