Buildings.Fluid.MassExchangers.Examples

Information

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

Package Content

Name	Description
ConstantEffectiveness
HumidifierPrescribed	Model that demonstrates the ideal humidifier model

Buildings.Fluid.MassExchangers.Examples.ConstantEffectiveness

Information

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.

Modelica definition

model ConstantEffectiveness
  extends Modelica.Icons.Example;

 package Medium1 = Buildings.Media.PerfectGases.MoistAirUnsaturated;
 package Medium2 = Buildings.Media.PerfectGases.MoistAirUnsaturated;

  Buildings.Fluid.Sources.Boundary_pT sin_2(
    redeclare package Medium = Medium2, T=273.15 + 10,
    use_p_in=true,
    nPorts=1);
    Modelica.Blocks.Sources.Ramp PIn(
    height=200,
    duration=60,
    offset=101330);
  Buildings.Fluid.Sources.Boundary_pT sou_2(
    redeclare package Medium = Medium2, T=273.15 + 5,
    use_p_in=true,
    use_T_in=true,
    nPorts=1);
    Modelica.Blocks.Sources.Ramp TWat(
    height=10,
    duration=60,
    offset=273.15 + 30,
    startTime=60) "Water temperature";
  Modelica.Blocks.Sources.Constant TDb(k=293.15) "Drybulb temperature";
    Modelica.Blocks.Sources.Constant POut(k=101325);
  Buildings.Fluid.Sources.Boundary_pT sin_1(
    redeclare package Medium = Medium1,
    T=273.15 + 30,
    X={0.012,1 - 0.012},
    use_p_in=true,
    p=300000,
    nPorts=1);
  Buildings.Fluid.Sources.Boundary_pT sou_1(
    redeclare package Medium = Medium1,
    T=273.15 + 50,
    X={0.012,1 - 0.012},
    use_T_in=true,
    p=100000,
    nPorts=1);
    Modelica.Blocks.Sources.Ramp PSin_1(
    duration=60,
    startTime=240,
    height=100,
    offset=1E5 - 110);
  Buildings.Fluid.MassExchangers.ConstantEffectiveness hex(
    redeclare package Medium1 = Medium1,
    redeclare package Medium2 = Medium2,
    m1_flow(start=5),
    m2_flow(start=5),
    m1_flow_nominal=5,
    m2_flow_nominal=5,
    dp1_nominal=100,
    dp2_nominal=100,
    show_T=true);
  inner Modelica.Fluid.System system;
equation 
  connect(PIn.y,sou_2. p_in);
  connect(TDb.y, sou_2.T_in);
  connect(TWat.y, sou_1.T_in);
  connect(PSin_1.y, sin_1.p_in);
  connect(sou_1.ports[1], hex.port_a1);
  connect(hex.port_a2, sou_2.ports[1]);
  connect(POut.y, sin_2.p_in);
  connect(hex.port_b1, sin_1.ports[1]);
  connect(hex.port_b2, sin_2.ports[1]);
end ConstantEffectiveness;

Buildings.Fluid.MassExchangers.Examples.HumidifierPrescribed

Information

Model that demonstrates the use of an ideal humidifier. Both humidifer models are identical, except that one model is configured as a steady-state model, whereas the other is configured as a dynamic model. Both humidifiers add water to the medium to track a set-point for the outlet temperature using adiabatic cooling. The temperature of the water that is added to the medium is determined by the parameter T of the humidifier models.

Parameters

Type	Name	Default	Description
MassFlowRate	m_flow_nominal	3000/1000/20	Nominal mass flow rate [kg/s]

Modelica definition

model HumidifierPrescribed 
  "Model that demonstrates the ideal humidifier model"
  extends Modelica.Icons.Example;

  package Medium = Buildings.Media.PerfectGases.MoistAirUnsaturated;

  inner Modelica.Fluid.System system;
  parameter Modelica.SIunits.MassFlowRate m_flow_nominal=
     3000/1000/20 "Nominal mass flow rate";

  Buildings.Fluid.Sources.MassFlowSource_T sou(
    redeclare package Medium = Medium,
    use_T_in=false,
    nPorts=2,
    m_flow=2*m_flow_nominal,
    T=303.15) "Source";
  Buildings.Fluid.MassExchangers.HumidifierPrescribed humSte(
    redeclare package Medium = Medium,
    m_flow_nominal=m_flow_nominal,
    dp_nominal=6000,
    tau=0,
    mWat_flow_nominal=m_flow_nominal*0.005,
    energyDynamics=Modelica.Fluid.Types.Dynamics.SteadyState) 
    "Steady-state model of the humidifier";
  Buildings.Fluid.Sensors.TemperatureTwoPort senTem1(redeclare package Medium
      = Medium, m_flow_nominal=m_flow_nominal) "Temperature sensor";
  Modelica.Blocks.Sources.TimeTable TSet(table=[0, 273.15 + 30; 120, 273.15 +
        30; 120, 273.15 + 25; 1200, 273.15 + 25]) "Setpoint";
  Buildings.Controls.Continuous.LimPID con1(
    Td=1,
    k=1,
    Ti=10,
    controllerType=Modelica.Blocks.Types.SimpleController.PI,
    reverseAction=true) "Controller";
  Buildings.Fluid.MassExchangers.HumidifierPrescribed humDyn(
    redeclare package Medium = Medium,
    m_flow_nominal=m_flow_nominal,
    dp_nominal=6000,
    mWat_flow_nominal=m_flow_nominal*0.005,
    energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial,
    massDynamics=Modelica.Fluid.Types.Dynamics.SteadyState,
    T_start=303.15) "Dynamic model of the humidifier";
  Buildings.Fluid.Sensors.TemperatureTwoPort senTem2(redeclare package Medium
      = Medium, m_flow_nominal=m_flow_nominal) "Temperature sensor";
  Buildings.Controls.Continuous.LimPID con2(
    Td=1,
    Ti=10,
    k=0.1,
    controllerType=Modelica.Blocks.Types.SimpleController.PI,
    reverseAction=true) "Controller";
  Buildings.Fluid.Sources.Boundary_pT sin(
    redeclare package Medium = Medium,
    use_T_in=false,
    p(displayUnit="Pa"),
    T=303.15,
    nPorts=2) "Sink";
equation 
  connect(senTem1.T, con1.u_m);
  connect(TSet.y, con1.u_s);
  connect(con1.y, humSte.u);
  connect(humSte.port_b, senTem1.port_a);
  connect(senTem2.T, con2.u_m);
  connect(TSet.y, con2.u_s);
  connect(con2.y, humDyn.u);
  connect(humDyn.port_b, senTem2.port_a);

  connect(sou.ports[1], humSte.port_a);
  connect(sou.ports[2], humDyn.port_a);
  connect(senTem1.port_b, sin.ports[1]);
  connect(senTem2.port_b, sin.ports[2]);
end HumidifierPrescribed;