model SupplyBranch "Supply branch of a dual duct system" replaceable package MediumA = Modelica.Media.Interfaces.PartialMedium "Medium model for air"; Modelica.Fluid.Interfaces.FluidPort_a port_aHot(redeclare package Medium = MediumA) "Connector for hot deck"; Modelica.Fluid.Interfaces.FluidPort_a port_aCol(redeclare package Medium = MediumA) "Connector for cold deck"; Modelica.Fluid.Interfaces.FluidPort_a port_b(redeclare package Medium = MediumA) "Fluid connector b (positive design flow direction is from port_a1 to port_b1)"; parameter Modelica.Fluid.Types.Dynamics energyDynamicsJunctions=Modelica.Fluid.Types.Dynamics.FixedInitial "Formulation of energy balance in junction volumes"; parameter Boolean dynamicBalanceJunction=true "Set to true to use a dynamic balance for junction volumes, which often leads to smaller systems of equations"; parameter Boolean from_dp=false "= true, use m_flow = f(dp) else dp = f(m_flow)"; parameter Boolean linearizeFlowResistance=false "= true, use linear relation between m_flow and dp for any flow rate"; parameter Modelica.SIunits.MassFlowRate m_flow_nominal "Mass flow rate cold air deck"; parameter Modelica.SIunits.MassFlowRate mAirHot_flow_nominal = 0.3*m_flow_nominal "Mass flow rate hot air deck"; parameter Modelica.SIunits.MassFlowRate mAirCol_flow_nominal = m_flow_nominal "Mass flow rate cold air deck"; parameter Modelica.SIunits.Volume VRoo "Room volume"; Controls.RoomMixingBox con(m_flow_min=VRoo*3*1.2/3600) "Room temperature controller"; VAVReheat.Controls.ControlBus controlBus; Buildings.Fluid.Actuators.Dampers.VAVBoxExponential vavHot( redeclare package Medium = MediumA, A=0.6, use_v_nominal=true, m_flow_nominal=mAirHot_flow_nominal, dp_nominal(displayUnit="Pa") = 40, from_dp=from_dp, linearized=linearizeFlowResistance) "VAV damper for hot deck"; Buildings.Fluid.Actuators.Dampers.VAVBoxExponential vavCol( redeclare package Medium = MediumA, A=0.6, use_v_nominal=true, m_flow_nominal=mAirCol_flow_nominal, dp_nominal(displayUnit="Pa") = 40, from_dp=from_dp, linearized=linearizeFlowResistance) "VAV damper for cold deck"; Buildings.Fluid.Sensors.MassFlowRate senMasFlo(redeclare package Medium = MediumA) "Sensor for mass flow rate"; Modelica.Blocks.Math.Gain fraMasFlo(k=1/m_flow_nominal) "Fraction of mass flow rate, relative to nominal flow"; Modelica.Blocks.Math.Gain ACH(k=1/VRoo/1.2*3600) "Air change per hour"; Modelica.Blocks.Interfaces.RealInput TRoo "Measured room temperature"; Fluid.FixedResistances.SplitterFixedResistanceDpM mix( redeclare package Medium = MediumA, m_flow_nominal={mAirCol_flow_nominal,mAirHot_flow_nominal,mAirCol_flow_nominal + mAirHot_flow_nominal}, energyDynamics=energyDynamicsJunctions, massDynamics=energyDynamicsJunctions, from_dp=from_dp, linearized=linearizeFlowResistance, dynamicBalance=false, dp_nominal=20*{0,0,0}) "Mixer for hot and cold air deck"; Fluid.Sensors.RelativePressure senRelPreHot(redeclare package Medium = MediumA) "Relative pressure hot deck (compared to room pressure)"; Fluid.Sensors.RelativePressure senRelPreCol(redeclare package Medium = MediumA) "Relative pressure cold deck (compared to room pressure)"; Modelica.Blocks.Interfaces.RealOutput p_relCol "Pressure signal of cold deck"; Modelica.Blocks.Interfaces.RealOutput p_relHot "Pressure signal of hot deck"; Fluid.Sensors.TemperatureTwoPort TSup(redeclare package Medium = MediumA, m_flow_nominal=m_flow_nominal) "Supply air temperature"; equation connect(fraMasFlo.u, senMasFlo.m_flow); connect(ACH.u, senMasFlo.m_flow); connect(con.TRoo, TRoo); connect(vavHot.port_a, port_aHot); connect(vavHot.port_b, mix.port_2); connect(mix.port_1, vavCol.port_b); connect(mix.port_3, senMasFlo.port_a); connect(senMasFlo.m_flow, con.mAir_flow); connect(con.yHot, vavHot.y); connect(con.yCol, vavCol.y); connect(senRelPreHot.port_a, port_aHot); connect(senRelPreCol.port_a, port_aCol); connect(vavCol.port_a, port_aCol); connect(senRelPreHot.port_b, mix.port_3); connect(senRelPreCol.port_b, mix.port_3); connect(senRelPreCol.p_rel, p_relCol); connect(senRelPreHot.p_rel, p_relHot); connect(con.TRooSetHea, controlBus.TRooSetHea); connect(con.TRooSetCoo, controlBus.TRooSetCoo); connect(senMasFlo.port_b, TSup.port_a); connect(TSup.port_b, port_b); end SupplyBranch;