Buildings.Media.PerfectGases.Examples

Collection of models that illustrate model use and test models

Information

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

Extends from Modelica.Icons.ExamplesPackage (Icon for packages containing runnable examples).

Package Content

Name Description

MoistAirTemperatureEnthalpyInversion Model to check computation of h(T) and its inverse

MoistAirUnsaturatedTemperatureEnthalpyInversion Model to check computation of h(T) and its inverse

MoistAirComparison

MoistAirDerivativeCheck

MoistAirUnsaturatedDerivativeCheck

TestMoistAir

TestMoistAirUnsaturated

Name	Description
MoistAirTemperatureEnthalpyInversion	Model to check computation of h(T) and its inverse
MoistAirUnsaturatedTemperatureEnthalpyInversion	Model to check computation of h(T) and its inverse
MoistAirComparison
MoistAirDerivativeCheck
MoistAirUnsaturatedDerivativeCheck
TestMoistAir
TestMoistAirUnsaturated

Buildings.Media.PerfectGases.Examples.MoistAirTemperatureEnthalpyInversion

Model to check computation of h(T) and its inverse

Information

Extends from Modelica.Icons.Example (Icon for runnable examples), Buildings.Media.BaseClasses.TestTemperatureEnthalpyInversion (Model to check computation of h(T) and its inverse).

Parameters

Type Name Default Description

replaceable package Medium PartialCondensingGases

Temperature T0 273.15 + 20 Temperature [K]

Type	Name	Default	Description
replaceable package Medium	PartialCondensingGases
Temperature	T0	273.15 + 20	Temperature [K]

Connectors

Type Name Description

replaceable package Medium

Type	Name	Description
replaceable package Medium

Modelica definition

model MoistAirTemperatureEnthalpyInversion 
  "Model to check computation of h(T) and its inverse"
  extends Modelica.Icons.Example;
  extends Buildings.Media.BaseClasses.TestTemperatureEnthalpyInversion(
    redeclare package Medium = Buildings.Media.PerfectGases.MoistAir);
end MoistAirTemperatureEnthalpyInversion;

Buildings.Media.PerfectGases.Examples.MoistAirUnsaturatedTemperatureEnthalpyInversion

Model to check computation of h(T) and its inverse

Information

Extends from Modelica.Icons.Example (Icon for runnable examples), Buildings.Media.BaseClasses.TestTemperatureEnthalpyInversion (Model to check computation of h(T) and its inverse).

Parameters

Type Name Default Description

replaceable package Medium PartialCondensingGases

Temperature T0 273.15 + 20 Temperature [K]

Type	Name	Default	Description
replaceable package Medium	PartialCondensingGases
Temperature	T0	273.15 + 20	Temperature [K]

Connectors

Type Name Description

replaceable package Medium

Type	Name	Description
replaceable package Medium

Modelica definition

model MoistAirUnsaturatedTemperatureEnthalpyInversion 
  "Model to check computation of h(T) and its inverse"
  extends Modelica.Icons.Example;
  extends Buildings.Media.BaseClasses.TestTemperatureEnthalpyInversion(
    redeclare package Medium =
        Buildings.Media.PerfectGases.MoistAirUnsaturated);
end MoistAirUnsaturatedTemperatureEnthalpyInversion;

Buildings.Media.PerfectGases.Examples.MoistAirComparison

Information

This example compares the perfect medium model Buildings.Media.PerfectGases.MoistAir with the ideal gas model from Modelica.Media.Air.MoistAir

Extends from Modelica.Icons.Example (Icon for runnable examples).

Parameters

Type Name Default Description

Pressure P 101325 Pressure [Pa]

Type	Name	Default	Description
Pressure	P	101325	Pressure [Pa]

Modelica definition

model MoistAirComparison
  extends Modelica.Icons.Example;

   package PerfectMedium = Buildings.Media.PerfectGases.MoistAir;
   package IdealMedium =   Modelica.Media.Air.MoistAir;

    Modelica.SIunits.SpecificEnthalpy hLiqPer "Liquid phase enthalpy";
    Modelica.SIunits.SpecificEnthalpy hLiqIde "Liquid phase enthalpy";
    Modelica.SIunits.SpecificEnthalpy hStePer "Water vapor enthalpy";
    Modelica.SIunits.SpecificEnthalpy hSteIde "Water vapor enthalpy";
    Modelica.SIunits.SpecificEnthalpy hAirPer "Air enthalpy";
    Modelica.SIunits.SpecificEnthalpy hAirIde "Air enthalpy";

    Modelica.SIunits.SpecificEnthalpy hMixPer "Mixture specific enthalpy";
    Modelica.SIunits.SpecificEnthalpy hMixIde "Mixture specific enthalpy";

    Modelica.SIunits.MassFraction X[2] = {0.01, 0.09};
    Modelica.SIunits.Temperature T "Temperature";
    Modelica.SIunits.Conversions.NonSIunits.Temperature_degC T_degC 
    "Temperature";

    Real errLiq "Error liquid phase";
    Real errSte "Error steam phase";
    Real errAir "Error gas mixture";
    Real errMix "Error gas mixture";
    Real errT 
    "Error in temperature when enthalpy-temperature relation is inverted";

    parameter Modelica.SIunits.Pressure P = 101325 "Pressure";

equation 
    T_degC = 1+99*time; // exclude 0, to avoid large relative error
    T = 273.15 + T_degC;
    hLiqPer=PerfectMedium.enthalpyOfLiquid(T);
    hStePer=PerfectMedium.enthalpyOfCondensingGas(T);
    hAirPer=PerfectMedium.enthalpyOfGas(T, X);
    hLiqIde=IdealMedium.enthalpyOfLiquid(T);
    hSteIde=IdealMedium.enthalpyOfCondensingGas(T);
    hAirIde=IdealMedium.enthalpyOfGas(T, X);

    hMixPer=PerfectMedium.h_pTX(P, T, X);
    hMixIde=IdealMedium.h_pTX(P, T, X);

    errLiq * abs(hLiqIde+1E-3) = hLiqIde - hLiqPer;
    errSte * abs(hSteIde+1E-3) = hSteIde - hStePer;
    errAir * abs(hAirIde+1E-3) = hAirIde - hAirPer;
    errMix * abs(hMixIde+1E-3) = hMixIde - hMixPer;
    errT * T = T - PerfectMedium.T_phX(P, PerfectMedium.h_pTX(P, T, X), X);

    assert( abs(errLiq) < 0.09, "Error too large. Check medium model.");
    assert( abs(errSte) < 0.01, "Error too large. Check medium model.");
    assert( abs(errAir) < 0.01, "Error too large. Check medium model.");
    assert( abs(errMix) < 2.01, "Error too large. Check medium model.");
    assert( abs(errT) < 0.01, "Error too large. Check medium model.");

end MoistAirComparison;

Buildings.Media.PerfectGases.Examples.MoistAirDerivativeCheck

Information

This example checks whether the function derivative is implemented correctly. If the derivative implementation is not correct, the model will stop with an assert statement.

Extends from Modelica.Icons.Example (Icon for runnable examples).

Modelica definition

model MoistAirDerivativeCheck
  extends Modelica.Icons.Example;

   package Medium = Buildings.Media.PerfectGases.MoistAir;

    Modelica.SIunits.SpecificEnthalpy hLiqSym "Liquid phase enthalpy";
    Modelica.SIunits.SpecificEnthalpy hLiqCod "Liquid phase enthalpy";
    Modelica.SIunits.SpecificEnthalpy hSteSym "Water vapor enthalpy";
    Modelica.SIunits.SpecificEnthalpy hSteCod "Water vapor enthalpy";
    Modelica.SIunits.SpecificEnthalpy hAirSym "Dry air enthalpy";
    Modelica.SIunits.SpecificEnthalpy hAirCod "Dry air enthalpy";
    constant Real conv(unit="K/s") = 1 
    "Conversion factor to satisfy unit check";
initial equation 
     hLiqSym = hLiqCod;
     hSteSym = hSteCod;
     hAirSym = hAirCod;
equation 
    hLiqCod=Medium.enthalpyOfLiquid(conv*time);
    der(hLiqCod)=der(hLiqSym);
    assert(abs(hLiqCod-hLiqSym) < 1E-2, "Model has an error");

    hSteCod=Medium.enthalpyOfCondensingGas(conv*time);
    der(hSteCod)=der(hSteSym);
    assert(abs(hSteCod-hSteSym) < 1E-2, "Model has an error");

    hAirCod=Medium.enthalpyOfDryAir(conv*time);
    der(hAirCod)=der(hAirSym);
    assert(abs(hAirCod-hAirSym) < 1E-2, "Model has an error");

end MoistAirDerivativeCheck;

Buildings.Media.PerfectGases.Examples.MoistAirUnsaturatedDerivativeCheck

Information

This example checks whether the function derivative is implemented correctly. If the derivative implementation is not correct, the model will stop with an assert statement.

Extends from Modelica.Icons.Example (Icon for runnable examples).

Modelica definition

model MoistAirUnsaturatedDerivativeCheck
  extends Modelica.Icons.Example;

   package Medium = Buildings.Media.PerfectGases.MoistAirUnsaturated;

    Modelica.SIunits.SpecificEnthalpy hLiqSym "Liquid phase enthalpy";
    Modelica.SIunits.SpecificEnthalpy hLiqCod "Liquid phase enthalpy";
    Modelica.SIunits.SpecificEnthalpy hSteSym "Water vapor enthalpy";
    Modelica.SIunits.SpecificEnthalpy hSteCod "Water vapor enthalpy";
    Modelica.SIunits.SpecificEnthalpy hAirSym "Dry air enthalpy";
    Modelica.SIunits.SpecificEnthalpy hAirCod "Dry air enthalpy";
    constant Real conv(unit="K/s") = 1 
    "Conversion factor to satisfy unit check";
initial equation 
     hLiqSym = hLiqCod;
     hSteSym = hSteCod;
     hAirSym = hAirCod;
equation 
    hLiqCod=Medium.enthalpyOfLiquid(conv*time);
    der(hLiqCod)=der(hLiqSym);
    assert(abs(hLiqCod-hLiqSym) < 1E-2, "Model has an error");

    hSteCod=Medium.enthalpyOfCondensingGas(conv*time);
    der(hSteCod)=der(hSteSym);
    assert(abs(hSteCod-hSteSym) < 1E-2, "Model has an error");

    hAirCod=Medium.enthalpyOfDryAir(conv*time);
    der(hAirCod)=der(hAirSym);
    assert(abs(hAirCod-hAirSym) < 1E-2, "Model has an error");

end MoistAirUnsaturatedDerivativeCheck;

Buildings.Media.PerfectGases.Examples.TestMoistAir

Information

This is a simple test for the medium model. It uses the test model described in Modelica.Media.UsersGuide.MediumDefinition.TestOfMedium.

Extends from Modelica.Icons.Example (Icon for runnable examples), Modelica.Media.Examples.Tests.Components.PartialTestModel (Basic test model to test a medium).

Parameters

Type Name Default Description

replaceable package Medium PartialMedium Medium model

AbsolutePressure p_start Medium.p_default Initial value of pressure [Pa]

Temperature T_start Medium.T_default Initial value of temperature [K]

SpecificEnthalpy h_start Medium.h_default Initial value of specific enthalpy [J/kg]

Real X_start[Medium.nX] Medium.X_default Initial value of mass fractions

Type	Name	Default	Description
replaceable package Medium	PartialMedium	Medium model
AbsolutePressure	p_start	Medium.p_default	Initial value of pressure [Pa]
Temperature	T_start	Medium.T_default	Initial value of temperature [K]
SpecificEnthalpy	h_start	Medium.h_default	Initial value of specific enthalpy [J/kg]
Real	X_start[Medium.nX]	Medium.X_default	Initial value of mass fractions

Connectors

Type Name Description

replaceable package Medium Medium model

Type	Name	Description
replaceable package Medium	Medium model

Modelica definition

model TestMoistAir
  extends Modelica.Icons.Example;
  extends Modelica.Media.Examples.Tests.Components.PartialTestModel(
     redeclare package Medium =
          Buildings.Media.PerfectGases.MoistAir);

end TestMoistAir;

Buildings.Media.PerfectGases.Examples.TestMoistAirUnsaturated

Information

This is a simple test for the medium model. It uses the test model described in Modelica.Media.UsersGuide.MediumDefinition.TestOfMedium.

Extends from Modelica.Icons.Example (Icon for runnable examples), Modelica.Media.Examples.Tests.Components.PartialTestModel (Basic test model to test a medium).

Parameters

Type	Name	Default	Description
replaceable package Medium	PartialMedium	Medium model
AbsolutePressure	p_start	Medium.p_default	Initial value of pressure [Pa]
Temperature	T_start	Medium.T_default	Initial value of temperature [K]
SpecificEnthalpy	h_start	Medium.h_default	Initial value of specific enthalpy [J/kg]
Real	X_start[Medium.nX]	Medium.X_default	Initial value of mass fractions

Connectors

Type Name Description

replaceable package Medium Medium model

Type	Name	Description
replaceable package Medium	Medium model

Modelica definition

model TestMoistAirUnsaturated
  extends Modelica.Icons.Example;
  extends Modelica.Media.Examples.Tests.Components.PartialTestModel(
     redeclare package Medium =
          Buildings.Media.PerfectGases.MoistAirUnsaturated);

end TestMoistAirUnsaturated;

Automatically generated Fri Nov 4 08:29:00 2011.