Buildings.Utilities.Psychrometrics.Functions.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.Utilities.Psychrometrics.Functions.
Extends from Modelica.Icons.ExamplesPackage (Icon for packages containing runnable examples).
Package Content
| Name | Description |
|---|---|
 Density_pTX
|
Model to test density_pTX |
| SaturationPressure
|
Model to test the saturationPressure function |
| X_pSatpphi
|
Model to test X_pSatpphi 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 |
| pW_X
|
Model to test pW_X and its inverse function |
| phi_pTX
|
Model to test phi_pTX |
Buildings.Utilities.Psychrometrics.Functions.Examples.Density_pTX
Model to test density_pTX
Information
Model that tests the implementation of Buildings.Utilities.Psychrometrics.Functions.density_pTX.
Extends from Modelica.Icons.Example (Icon for runnable examples).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Pressure | p | 101325 | Pressure of the medium [Pa] |
Modelica definition
model Density_pTX "Model to test density_pTX"
extends Modelica.Icons.Example;
parameter Modelica.Units.SI.Pressure p=101325 "Pressure of the medium";
Modelica.Units.SI.Temperature T "Temperature";
Modelica.Units.SI.MassFraction X_w "Mass fraction";
Modelica.Units.SI.Density d "Mass density";
constant Real convT(unit="1/s") = 0.999 "Conversion factor";
constant Real convX(unit="1/s") = 0.02 "Conversion factor";
equation
if time < 0.5 then
X_w = convX*time;
T = 293.15;
else
X_w = 0.5*convX;
T = 293.15+convT*(time-0.5)*10;
end if;
d = Buildings.Utilities.Psychrometrics.Functions.density_pTX(p=p, T=T, X_w=X_w);
end Density_pTX;
Buildings.Utilities.Psychrometrics.Functions.Examples.SaturationPressure
Model to test the saturationPressure function
Information
This example computes the saturation pressure of water.
Extends from Modelica.Icons.Example (Icon for runnable examples).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Temperature | TMin | 190 | Temperature [K] |
| Temperature | TMax | 373.16 | Temperature [K] |
Modelica definition
model SaturationPressure "Model to test the saturationPressure function"
extends Modelica.Icons.Example;
parameter Modelica.Units.SI.Temperature TMin=190 "Temperature";
parameter Modelica.Units.SI.Temperature TMax=373.16 "Temperature";
Modelica.Units.SI.Temperature T "Temperature";
Modelica.Units.SI.AbsolutePressure pSat "Saturation pressure";
constant Real conv(unit="1/s") = 1 "Conversion factor";
equation
T = TMin + conv*time * (TMax-TMin);
pSat = Buildings.Utilities.Psychrometrics.Functions.saturationPressure(T);
end SaturationPressure;
Buildings.Utilities.Psychrometrics.Functions.Examples.X_pSatpphi
Model to test X_pSatpphi function
Information
This example computes the water content of air for a relative humidity between 0 and 100%, a temperature of 20°C 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.Air "Medium model";
parameter Modelica.Units.SI.Temperature T=293.15 "Temperature";
parameter Modelica.Units.SI.Pressure p=101325 "Pressure of the fluid";
Modelica.Units.SI.AbsolutePressure pSat "Saturation pressure";
Real phi(min=0, max=1) "Relative humidity";
Modelica.Units.SI.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*conv;
pSat = Medium.saturationPressure(T);
X_w = Buildings.Utilities.Psychrometrics.Functions.X_pSatpphi(pSat=pSat, p=p, phi=phi);
end X_pSatpphi;
Buildings.Utilities.Psychrometrics.Functions.Examples.pW_TDewPoi
Model to test pW_TDewPoi and its inverse function
Information
Extends from Modelica.Icons.Example (Icon for runnable examples).
Modelica definition
model pW_TDewPoi "Model to test pW_TDewPoi and its inverse function"
extends Modelica.Icons.Example;
Modelica.Units.SI.Temperature T "Dew point temperature";
Modelica.Units.SI.Temperature TInv "Dew point temperature";
Modelica.Units.SI.TemperatureDifference dT "Difference between temperatures";
Modelica.Units.SI.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
Model to test the approximation for pW_TDewPoi and its inverse function
Information
Extends from Modelica.Icons.Example (Icon for runnable examples).
Modelica definition
model pW_TDewPoi_comparison
"Model to test the approximation for pW_TDewPoi and its inverse function"
extends Modelica.Icons.Example;
Modelica.Units.SI.Temperature T "Dew point temperature";
Modelica.Units.SI.Temperature TInv "Dew point temperature";
Modelica.Units.SI.TemperatureDifference dT "Difference between temperatures";
Modelica.Units.SI.Pressure p_w_ashrae
"Water vapor partial pressure according to the ASHRAE handbook";
Modelica.Units.SI.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.pW_X
Model to test pW_X and its inverse function
Information
Extends from Modelica.Icons.Example (Icon for runnable examples).
Modelica definition
model pW_X "Model to test pW_X and its inverse function"
extends Modelica.Icons.Example;
Modelica.Units.SI.MassFraction X "Mass fraction";
Modelica.Units.SI.MassFraction XInv "Mass fraction";
Modelica.Units.SI.MassFraction dX "Difference between mass fraction";
Modelica.Units.SI.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.phi_pTX
Model to test phi_pTX
Information
Extends from Modelica.Icons.Example (Icon for runnable examples).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Pressure | p | 101325 | Pressure of the medium [Pa] |
Modelica definition
model phi_pTX "Model to test phi_pTX"
extends Modelica.Icons.Example;
parameter Modelica.Units.SI.Pressure p=101325 "Pressure of the medium";
Modelica.Units.SI.Temperature T "Temperature";
Modelica.Units.SI.MassFraction X_w "Mass fraction";
Real phi "Relative humidity";
Real X_inv "Inverse computation of mass fraction";
constant Real convT(unit="1/s") = 0.999 "Conversion factor";
constant Real convX(unit="1/s") = 0.02 "Conversion factor";
equation
if time < 0.5 then
X_w = convX*time;
T = 293.15;
else
X_w = 0.5*convX;
T = 293.15+convT*(time-0.5)*10;
end if;
phi = Buildings.Utilities.Psychrometrics.Functions.phi_pTX(p=p, T=T, X_w=X_w);
X_inv=Buildings.Utilities.Psychrometrics.Functions.X_pTphi(p=p, T=T, phi=phi);
assert(abs(X_inv-X_w) < 1e-5,
"Inconsistency in the inverse implementation of phi_pTX: X_pTphi");
end phi_pTX;