The model represents an air-based heating system with an ideal heater and an ideal humidifier
in the supply duct. The heater and humidifier are controlled with a feedback loop that
tracks the room air temperature and room air humidity. These quantities are simulated
in the EnergyPlus simulation program through the Building Controls Virtual Test Bed.
The component bouBCVTB
models the boundary between the domain that models the air
system (in Modelica) and the room response (in EnergyPlus).
model MoistAir
extends Modelica.Icons.Example;
package Medium =
Buildings.Media.Air;
parameter Modelica.SIunits.MassFlowRate m_flow_nominal=
259.2*6/1.2/3600 ;
Buildings.Fluid.FixedResistances.FixedResistanceDpM dp1(
redeclare package Medium = Medium,
m_flow_nominal=m_flow_nominal,
dp_nominal=200,
from_dp=false,
allowFlowReversal=false);
Buildings.Fluid.Sources.Boundary_pT sou(
nPorts=2,
redeclare package Medium = Medium,
use_T_in=true,
use_X_in=true,
p(displayUnit="Pa") = 101325,
T=293.15);
Buildings.Fluid.FixedResistances.FixedResistanceDpM dp2(
redeclare package Medium = Medium,
m_flow_nominal=m_flow_nominal,
dp_nominal=200,
from_dp=false,
allowFlowReversal=false);
Buildings.Utilities.IO.BCVTB.MoistAirInterface bouBCVTB(
nPorts=2,
redeclare package Medium = Medium,
m_flow=0,
use_m_flow_in=false,
m_flow_nominal=m_flow_nominal);
Buildings.Fluid.MassExchangers.Humidifier_u hum(
m_flow_nominal=m_flow_nominal,
dp_nominal=200,
redeclare package Medium = Medium,
mWat_flow_nominal=0.01*m_flow_nominal,
from_dp=false,
allowFlowReversal=false,
use_T_in=false) ;
Buildings.Fluid.HeatExchangers.HeaterCooler_u hex(
m_flow_nominal=m_flow_nominal,
dp_nominal=200,
redeclare package Medium = Medium,
Q_flow_nominal=m_flow_nominal*50*1006,
from_dp=false,
allowFlowReversal=false) ;
Buildings.Fluid.Sensors.TemperatureTwoPort
TRet(
redeclare package Medium = Medium,
m_flow_nominal=m_flow_nominal) ;
Buildings.Fluid.Sensors.MassFractionTwoPort
Xi_w(
redeclare package Medium = Medium,
m_flow_nominal=m_flow_nominal) ;
Modelica.Blocks.Sources.Constant XSet(k=0.005) ;
Modelica.Blocks.Sources.Constant TRooSetNig(k=273.15 + 16) ;
Buildings.Controls.Continuous.LimPID PIDHea(
yMax=1,
yMin=0,
Td=1,
controllerType=Modelica.Blocks.Types.SimpleController.PI,
k=0.1,
Ti=600) ;
Buildings.Controls.Continuous.LimPID PIDHum(
yMax=1,
yMin=0,
controllerType=Modelica.Blocks.Types.SimpleController.PI,
k=20,
Td=60,
Ti=600) ;
Buildings.Utilities.IO.BCVTB.BCVTB bcvtb(
xmlFileName="socket.cfg",
nDblRea=4,
nDblWri=5,
flaDblWri={1,1,1,1,1},
uStart={0,0,0,0,20},
activateInterface=true,
timeStep=60);
Modelica.Blocks.Routing.DeMultiplex4 deMultiplex2_1(
n1=1,
n2=1,
n3=1,
n4=1);
Modelica.Blocks.Routing.Multiplex5 mul;
Buildings.Fluid.Sensors.TemperatureTwoPort
TSup(
redeclare package Medium = Medium,
m_flow_nominal=m_flow_nominal) ;
Buildings.Fluid.Movers.SpeedControlled_y fan(
redeclare package Medium = Medium,
per(pressure(V_flow={0,m_flow_nominal/1.2}, dp={2*400,400})),
energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial);
Modelica.Blocks.Sources.Constant yFan(k=1) ;
Modelica.Blocks.Math.Gain perToRel(k=0.01) ;
Modelica.Blocks.Math.Gain perToRel1(
k=0.01) ;
Buildings.Utilities.Psychrometrics.X_pTphi masFra(use_p_in=false) ;
Buildings.Controls.SetPoints.OccupancySchedule occSch ;
Modelica.Blocks.Logical.Switch switch1;
Modelica.Blocks.Sources.Constant TRooSetDay(k=273.15 + 20) ;
Buildings.Utilities.IO.BCVTB.From_degC from_degC;
Buildings.Utilities.IO.BCVTB.To_degC to_degC;
Buildings.Utilities.IO.BCVTB.From_degC from_degC1;
equation
connect(dp1.port_a, hum.port_b);
connect(hex.port_b, hum.port_a);
connect(TRet.T, PIDHea.u_m);
connect(PIDHea.y, hex.u);
connect(XSet.y, PIDHum.u_s);
connect(PIDHum.y, hum.u);
connect(bcvtb.yR, deMultiplex2_1.u);
connect(mul.y, bcvtb.uR);
connect(PIDHum.y, mul.u4[1]);
connect(PIDHea.y, mul.u3[1]);
connect(mul.u1[1], bouBCVTB.HSen_flow);
connect(bouBCVTB.HLat_flow, mul.u2[1]);
connect(Xi_w.X, PIDHum.u_m);
connect(fan.port_b, hex.port_a);
connect(fan.port_a, sou.ports[1]);
connect(perToRel.y, bouBCVTB.phi);
connect(deMultiplex2_1.y4[1], perToRel.u);
connect(perToRel1.u, deMultiplex2_1.y3[1]);
connect(masFra.phi, perToRel1.y);
connect(masFra.X, sou.X_in);
connect(yFan.y, fan.y);
connect(occSch.occupied, switch1.u2);
connect(TRooSetNig.y, switch1.u3);
connect(TRooSetDay.y, switch1.u1);
connect(switch1.y, PIDHea.u_s);
connect(from_degC.Kelvin, bouBCVTB.T_in);
connect(TSup.T, to_degC.Kelvin);
connect(to_degC.Celsius, mul.u5[1]);
connect(from_degC1.Kelvin, sou.T_in);
connect(from_degC1.Celsius, deMultiplex2_1.y1[1]);
connect(deMultiplex2_1.y2[1], from_degC.Celsius);
connect(from_degC1.Kelvin, masFra.T);
connect(dp2.port_b, Xi_w.port_a);
connect(Xi_w.port_b, TRet.port_a);
connect(TRet.port_b, sou.ports[2]);
connect(dp1.port_b, TSup.port_a);
connect(TSup.port_b, bouBCVTB.ports[1]);
connect(dp2.port_a, bouBCVTB.ports[2]);
end MoistAir;
Given a control signal for two heat flow rates, Modelica simulates the thermal response
of two first order systems. The two systems may represent a first order approximation of a room.
The control signal for the heat flow rate is computed in the Building Controls Virtual Test Bed
using a discrete time implementation of a proportional controller.
Every 60 seconds, measured temperatures and control signals for the heat flow rates are
exchanged between Dymola and the Building Controls Virtual Test Bed.
model TwoRooms
extends Modelica.Icons.Example;
parameter Modelica.SIunits.Time tau = 2*3600 ;
parameter Modelica.SIunits.HeatFlowRate Q_flow_nom = 100 ;
parameter Modelica.SIunits.ThermalConductance UA = Q_flow_nom / 20 ;
parameter Modelica.SIunits.Temperature TStart = 283.15 ;
Modelica.Thermal.HeatTransfer.Components.HeatCapacitor C1(C=tau*UA, T(start=
TStart, fixed=true)) ;
Modelica.Thermal.HeatTransfer.Components.ThermalConductor UA1(G=UA) ;
Buildings.HeatTransfer.Sources.FixedTemperature TOut1(T=278.15) ;
Buildings.HeatTransfer.Sources.PrescribedHeatFlow Q_flow_1 ;
Modelica.Blocks.Math.Gain GaiQ_flow_nom1(k=Q_flow_nom) ;
Modelica.Thermal.HeatTransfer.Components.ThermalConductor UA2(G=UA) ;
Modelica.Thermal.HeatTransfer.Components.HeatCapacitor C2(C=2*tau*UA, T(start=
TStart, fixed=true)) ;
Buildings.HeatTransfer.Sources.FixedTemperature TOut2(T=278.15) ;
Buildings.HeatTransfer.Sources.PrescribedHeatFlow Q_flow_2 ;
Modelica.Blocks.Math.Gain GaiQ_flow_nom2(k=Q_flow_nom) ;
Modelica.Thermal.HeatTransfer.Sensors.TemperatureSensor TRoo1 ;
Modelica.Thermal.HeatTransfer.Sensors.TemperatureSensor TRoo2 ;
Buildings.Utilities.IO.BCVTB.BCVTB bcvtb(
xmlFileName="socket.cfg",
uStart={TStart - 273.15,TStart - 273.15},
timeStep=60,
final nDblWri=2,
final nDblRea=2);
Modelica.Blocks.Routing.Multiplex2 multiplex2_1;
Modelica.Blocks.Routing.DeMultiplex2 deMultiplex2_1;
Buildings.Utilities.IO.BCVTB.To_degC to_degC1;
Buildings.Utilities.IO.BCVTB.To_degC to_degC2;
equation
connect(TOut1.port, UA1.port_a);
connect(UA1.port_b, C1.port);
connect(TOut2.port, UA2.port_a);
connect(UA2.port_b, C2.port);
connect(Q_flow_1.port, C1.port);
connect(Q_flow_2.port, C2.port);
connect(C1.port, TRoo1.port);
connect(C2.port, TRoo2.port);
connect(GaiQ_flow_nom1.y, Q_flow_1.Q_flow);
connect(GaiQ_flow_nom2.y, Q_flow_2.Q_flow);
connect(bcvtb.yR, deMultiplex2_1.u);
connect(deMultiplex2_1.y1[1], GaiQ_flow_nom1.u);
connect(deMultiplex2_1.y2[1], GaiQ_flow_nom2.u);
connect(multiplex2_1.y, bcvtb.uR);
connect(TRoo1.T, to_degC1.Kelvin);
connect(TRoo2.T, to_degC2.Kelvin);
connect(to_degC2.Celsius, multiplex2_1.u2[1]);
connect(to_degC1.Celsius, multiplex2_1.u1[1]);
end TwoRooms;