Buildings.Utilities.Psychrometrics.Functions.Examples

Information

This package contains examples for the use of models that can be found in Buildings.Utilities.Psychrometrics.Functions.

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

Package Content

Name	Description
pW_X	Model to test pW_X and its inverse function
pW_TDewPoi	Model to test pW_TDewPoi and its inverse function
pW_TDewPoi_comparison	Model to test the approximation for pW_TDewPoi and its inverse function
X_pSatpphi	Model to test X_pSatpphi function

Buildings.Utilities.Psychrometrics.Functions.Examples.pW_X

Information

Modelica definition

model pW_X "Model to test pW_X and its inverse function"
  extends Modelica.Icons.Example;

  Modelica.SIunits.MassFraction X "Mass fraction";
  Modelica.SIunits.MassFraction XInv "Mass fraction";
  Modelica.SIunits.MassFraction dX "Difference between mass fraction";
  Modelica.SIunits.Pressure p_w "Water vapor partial pressure";
  constant Real conv(unit="1/s") = 0.999 "Conversion factor";
equation 
  X = conv*time;
  p_w = Buildings.Utilities.Psychrometrics.Functions.pW_X(X);
  XInv = Buildings.Utilities.Psychrometrics.Functions.X_pW(p_w);
  dX = X - XInv;
  assert(abs(dX) < 10E-12, "Error in function implementation.");
end pW_X;

Buildings.Utilities.Psychrometrics.Functions.Examples.pW_TDewPoi

Information

Modelica definition

model pW_TDewPoi "Model to test pW_TDewPoi and its inverse function"
  extends Modelica.Icons.Example;

  Modelica.SIunits.Temperature T "Dew point temperature";
  Modelica.SIunits.Temperature TInv "Dew point temperature";
  Modelica.SIunits.TemperatureDifference dT "Difference between temperatures";
  Modelica.SIunits.Pressure p_w "Water vapor partial pressure";
  constant Real conv(unit="K/s") = 100 "Conversion factor";
equation 
  T = conv*time + 273.15;
  p_w = Buildings.Utilities.Psychrometrics.Functions.pW_TDewPoi(T);
  TInv = Buildings.Utilities.Psychrometrics.Functions.TDewPoi_pW(p_w);
  dT = T - TInv;
  assert(abs(dT) < 10E-12, "Error in function implementation.");
end pW_TDewPoi;

Buildings.Utilities.Psychrometrics.Functions.Examples.pW_TDewPoi_comparison

Information

Modelica definition

model pW_TDewPoi_comparison 
  "Model to test the approximation for pW_TDewPoi and its inverse function"
  extends Modelica.Icons.Example;

  Modelica.SIunits.Temperature T "Dew point temperature";
  Modelica.SIunits.Temperature TInv "Dew point temperature";
  Modelica.SIunits.TemperatureDifference dT "Difference between temperatures";
  Modelica.SIunits.Pressure p_w_ashrae 
    "Water vapor partial pressure according to the ASHRAE handbook";
  Modelica.SIunits.Pressure p_w "Water vapor partial pressure";

  constant Real conv(unit="K/s") = 30 "Conversion factor";
  Real r_p "Ratio of the two approximations";
equation 
  T = conv*time + 273.15;
  p_w_ashrae = Buildings.Utilities.Psychrometrics.Functions.pW_TDewPoi(T);
  p_w = Buildings.Utilities.Psychrometrics.Functions.pW_TDewPoi_amb(T);
  r_p = p_w_ashrae/p_w;
  p_w = Buildings.Utilities.Psychrometrics.Functions.pW_TDewPoi_amb(TInv);
  dT = T - TInv;
  assert(abs(dT) < 10E-12, "Error in function implementation.");
end pW_TDewPoi_comparison;

Buildings.Utilities.Psychrometrics.Functions.Examples.X_pSatpphi

Information

This example computes the water content of air for a relative humidity between 0 and 100%, a temperature of 20ˆC and atmospheric pressure.

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

Parameters

Type	Name	Default	Description
Temperature	T	293.15	Temperature [K]
Pressure	p	101325	Pressure of the fluid [Pa]

Modelica definition

model X_pSatpphi "Model to test X_pSatpphi function"
  extends Modelica.Icons.Example;
  package Medium = Buildings.Media.PerfectGases.MoistAir "Medium model";
  parameter Modelica.SIunits.Temperature T = 293.15 "Temperature";
  Modelica.SIunits.AbsolutePressure pSat "Saturation pressure";
  parameter Modelica.SIunits.Pressure p = 101325 "Pressure of the fluid";
  Real phi(min=0, max=1) "Relative humidity";
  Modelica.SIunits.MassFraction X_w(
    min=0,
    max=1,
    nominal=0.01) "Water vapor concentration per total mass of air";

  constant Real conv(unit="1/s") = 1 "Conversion factor";
equation 
  phi = time;
  pSat = Medium.saturationPressure(T);
  X_w = Buildings.Utilities.Psychrometrics.Functions.X_pSatpphi(pSat=pSat, p=p, phi=phi);

end X_pSatpphi;