Buildings.Utilities.Psychrometrics.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.
Extends from Modelica.Icons.ExamplesPackage (Icon for packages containing runnable examples).
Package Content
| Name | Description |
|---|---|
 Density_pTX
|
Model to test the density computation |
| DewPointTemperature
|
Unit test for dew point temperature calculation |
| HumidityRatioPressure
|
Unit test for humidity ratio model |
| MassFraction_pTphi
|
Unit test for dew point temperature calculation |
| Phi_pTX
|
Model to test the relative humidity computation |
| SaturationPressure
|
Model to test the wet bulb temperature computation |
| SaturationPressureLiquid
|
Model to test the wet bulb temperature computation |
| SublimationPressureIce
|
Model to test the wet bulb temperature computation |
| TWetBul_TDryBulPhi
|
Model to test the wet bulb temperature computation |
| TWetBul_TDryBulXi
|
|
| TotalAirDryAir
|
Unit test for conversion of humidity per total air and dry air mass |
Buildings.Utilities.Psychrometrics.Examples.Density_pTX
Model to test the density computation
Information
This examples is a unit test for the density computation.
Extends from Modelica.Icons.Example (Icon for runnable examples).
Modelica definition
model Density_pTX "Model to test the density computation"
extends Modelica.Icons.Example;
package Medium = Buildings.Media.Air "Medium model";
Modelica.Blocks.Sources.Constant p(k=101325) "Pressure";
Modelica.Blocks.Sources.Ramp XDryBul(
height=0.014,
offset=0,
duration=0.5) "Dry bulb water vapor mass fraction";
Buildings.Utilities.Psychrometrics.Density_pTX den "Density";
Modelica.Blocks.Sources.Ramp TDryBul(
duration=0.5,
startTime=0.5,
height=-10,
offset=303.15) "Dry bulb temperature";
equation
connect(XDryBul.y, den.X_w);
connect(den.p, p.y);
connect(TDryBul.y, den.T);
end Density_pTX;
Buildings.Utilities.Psychrometrics.Examples.DewPointTemperature
Unit test for dew point temperature calculation
Information
Extends from Modelica.Icons.Example (Icon for runnable examples).
Modelica definition
model DewPointTemperature "Unit test for dew point temperature calculation"
extends Modelica.Icons.Example;
package Medium = Buildings.Media.Air "Medium model";
Buildings.Utilities.Psychrometrics.pW_TDewPoi watVapPre;
Modelica.Blocks.Sources.Ramp XHum(
duration=1,
height=(0.01 - 0.1),
offset=0.1) "Humidity concentration";
Buildings.Utilities.Psychrometrics.pW_X humRat(
use_p_in=false);
Buildings.Utilities.Psychrometrics.TDewPoi_pW TDewPoi;
equation
connect(XHum.y, humRat.X_w);
connect(humRat.p_w, TDewPoi.p_w);
connect(TDewPoi.T, watVapPre.T);
end DewPointTemperature;
Buildings.Utilities.Psychrometrics.Examples.HumidityRatioPressure
Unit test for humidity ratio model
Information
Extends from Modelica.Icons.Example (Icon for runnable examples).
Modelica definition
model HumidityRatioPressure "Unit test for humidity ratio model"
extends Modelica.Icons.Example;
package Medium = Buildings.Media.Air "Medium model";
Buildings.Utilities.Psychrometrics.pW_X vapPre(
use_p_in=true) "Model for humidity ratio";
Modelica.Blocks.Sources.Ramp XHumDryAir(
duration=1,
height=(0.0133 - 0.2),
offset=0.2) "Humidity concentration in [kg/kg dry air]";
Modelica.Blocks.Sources.Constant p(k=101325) "Pressure";
Buildings.Utilities.Psychrometrics.X_pW humRat(
use_p_in=true);
Diagnostics.AssertEquality assertEquality(threShold=1E-5)
"Checks that model and its inverse implementation are correct";
ToTotalAir toTotalAir;
equation
connect(vapPre.p_w, humRat.p_w);
connect(humRat.X_w, assertEquality.u1);
connect(p.y, humRat.p_in);
connect(p.y, vapPre.p_in);
connect(XHumDryAir.y, toTotalAir.XiDry);
connect(toTotalAir.XiTotalAir, vapPre.X_w);
connect(toTotalAir.XiTotalAir, assertEquality.u2);
end HumidityRatioPressure;
Buildings.Utilities.Psychrometrics.Examples.MassFraction_pTphi
Unit test for dew point temperature calculation
Information
Extends from Modelica.Icons.Example (Icon for runnable examples).
Modelica definition
model MassFraction_pTphi "Unit test for dew point temperature calculation"
extends Modelica.Icons.Example;
package Medium1 = Buildings.Media.Air "Medium model";
package Medium2 = Buildings.Media.Air "Medium model";
Modelica.Blocks.Sources.Ramp Phi(
offset=0,
duration=0.5,
height=1) "Relative humidity";
Buildings.Utilities.Psychrometrics.X_pTphi masFra1
"Mass fraction computation";
Modelica.Blocks.Sources.Ramp T(
height=10,
offset=283.15,
duration=0.5,
startTime=0.5) "Temperature";
Modelica.Blocks.Sources.Constant P(k=101325) "Pressure";
Buildings.Utilities.Psychrometrics.X_pTphi masFra2(use_p_in=false)
"Mass fraction computation";
equation
connect(T.y, masFra1.T);
connect(Phi.y, masFra1.phi);
connect(T.y, masFra2.T);
connect(Phi.y, masFra2.phi);
connect(P.y, masFra1.p_in);
end MassFraction_pTphi;
Buildings.Utilities.Psychrometrics.Examples.Phi_pTX
Model to test the relative humidity computation
Information
This examples is a unit test for the relative humidity computation.
Extends from Modelica.Icons.Example (Icon for runnable examples).
Modelica definition
model Phi_pTX "Model to test the relative humidity computation"
extends Modelica.Icons.Example;
package Medium = Buildings.Media.Air "Medium model";
Modelica.Blocks.Sources.Constant p(k=101325) "Pressure";
Modelica.Blocks.Sources.Ramp XDryBul(
height=0.014,
offset=0,
duration=0.5) "Dry bulb water vapor mass fraction";
Buildings.Utilities.Psychrometrics.Phi_pTX phi "Relative humidity";
Modelica.Blocks.Sources.Ramp TDryBul(
duration=0.5,
startTime=0.5,
height=-10,
offset=303.15) "Dry bulb temperature";
equation
connect(XDryBul.y, phi.X_w);
connect(phi.p, p.y);
connect(TDryBul.y, phi.T);
end Phi_pTX;
Buildings.Utilities.Psychrometrics.Examples.SaturationPressure
Model to test the wet bulb temperature computation
Information
This examples is a unit test for the saturation pressure computation.Extends from Modelica.Icons.Example (Icon for runnable examples).
Modelica definition
model SaturationPressure "Model to test the wet bulb temperature computation"
extends Modelica.Icons.Example;
package Medium = Buildings.Media.Air "Medium model";
Buildings.Utilities.Psychrometrics.SaturationPressure pSat
"Saturation pressure";
Modelica.Blocks.Sources.Ramp T(
height=373.15 - 190,
duration=1,
offset=190) "Temperature";
equation
connect(T.y, pSat.TSat);
end SaturationPressure;
Buildings.Utilities.Psychrometrics.Examples.SaturationPressureLiquid
Model to test the wet bulb temperature computation
Information
This examples is a unit test for the saturation pressure computation of liquid water.Extends from Modelica.Icons.Example (Icon for runnable examples).
Modelica definition
model SaturationPressureLiquid
"Model to test the wet bulb temperature computation"
extends Modelica.Icons.Example;
Buildings.Utilities.Psychrometrics.SaturationPressureLiquid pSat
"Saturation pressure";
Modelica.Blocks.Sources.Ramp T(
height=100,
duration=1,
offset=273.15) "Temperature";
equation
connect(T.y, pSat.TSat);
end SaturationPressureLiquid;
Buildings.Utilities.Psychrometrics.Examples.SublimationPressureIce
Model to test the wet bulb temperature computation
Information
This examples is a unit test for the sublimation pressure computation of ice.Extends from Modelica.Icons.Example (Icon for runnable examples).
Modelica definition
model SublimationPressureIce
"Model to test the wet bulb temperature computation"
extends Modelica.Icons.Example;
Buildings.Utilities.Psychrometrics.SublimationPressureIce pSat
"Saturation pressure";
Modelica.Blocks.Sources.Ramp T(
height=273.15 - 190,
duration=1,
offset=190) "Temperature";
equation
connect(T.y, pSat.TSat);
end SublimationPressureIce;
Buildings.Utilities.Psychrometrics.Examples.TWetBul_TDryBulPhi
Model to test the wet bulb temperature computation
Information
This examples is a unit test for the wet bulb computation. The model on the top uses the accurate computation of the wet bulb temperature, whereas the model below uses the approximate computation of the wet bulb temperature.
The model contains an assert that validates the model based on a single operating point from Example 17.1 in Ananthanarayanan (2013).
References
Ananthanarayanan, P. N. Basic refrigeration and air conditioning. Tata McGraw-Hill Education, 2013.
Extends from Modelica.Icons.Example (Icon for runnable examples).
Modelica definition
model TWetBul_TDryBulPhi "Model to test the wet bulb temperature computation"
extends Modelica.Icons.Example;
package Medium = Buildings.Media.Air "Medium model";
Buildings.Utilities.Psychrometrics.TWetBul_TDryBulPhi wetBulPhi(
redeclare package Medium = Medium) "Model for wet bulb temperature";
Modelica.Blocks.Sources.Constant p(k=101325) "Pressure";
Modelica.Blocks.Sources.Ramp phi(
duration=1,
height=1,
offset=0) "Relative humidity";
Modelica.Blocks.Sources.Constant TDryBul(k=273.15 + 29.4)
"Dry bulb temperature";
Buildings.Utilities.Psychrometrics.TWetBul_TDryBulPhi wetBulPhiApp(
redeclare package Medium = Medium,
approximateWetBulb=true) "Model for wet bulb temperature";
Buildings.Utilities.Psychrometrics.TWetBul_TDryBulXi wetBulXi(
redeclare package Medium = Medium)
"Model for wet bulb temperature using Xi as an input, used to verify consistency with wetBulPhi";
Buildings.Utilities.Psychrometrics.X_pTphi x_pTphi "Computes mass fraction";
protected
block Assertions
extends Modelica.Blocks.Icons.Block;
constant Modelica.SIunits.Temperature dT_max=0.1
"Maximum allowed deviation with reference result";
Modelica.Blocks.Interfaces.RealInput phi "Relative humidity";
Modelica.Blocks.Interfaces.RealInput wetBulPhi_TWetBul
"Wet bulb temperature from wetBulPhi_phi";
Modelica.Blocks.Interfaces.RealInput wetBulXi_TWetBul
"Wet bulb temperature from wetBulXi_phi";
equation
// Validation of one data point based on example 17.1 in
// Ananthanarayanan, P. N. Basic refrigeration and air conditioning. Tata McGraw-Hill Education, 2013.
if abs(phi-0.48)<0.001 then
assert(abs(wetBulPhi_TWetBul - 21.1-273.15) < dT_max,
"Error in computation of wet bulb temperature, deviation with reference result is larger than "
+ String(dT_max) + " K since the wet bulb temperature equals " +String(wetBulPhi_TWetBul));
end if;
assert(abs(wetBulPhi_TWetBul-wetBulXi_TWetBul)<1e-2, "Inconsistent implementation of wetBulPhi and wetBulXi.");
end Assertions;
Assertions assertions "Verifies that the results are correct";
equation
connect(p.y, wetBulPhi.p);
connect(TDryBul.y, wetBulPhi.TDryBul);
connect(phi.y, wetBulPhi.phi);
connect(p.y, wetBulPhiApp.p);
connect(TDryBul.y, wetBulPhiApp.TDryBul);
connect(phi.y, wetBulPhiApp.phi);
connect(wetBulXi.TDryBul, TDryBul.y);
connect(wetBulXi.p, p.y);
connect(x_pTphi.p_in, p.y);
connect(x_pTphi.T, TDryBul.y);
connect(x_pTphi.phi, phi.y);
connect(x_pTphi.X[1], wetBulXi.Xi[1]);
connect(wetBulPhi.TWetBul, assertions.wetBulPhi_TWetBul);
connect(wetBulXi.TWetBul, assertions.wetBulXi_TWetBul);
connect(assertions.phi, phi.y);
end TWetBul_TDryBulPhi;
Buildings.Utilities.Psychrometrics.Examples.TWetBul_TDryBulXi
Information
This examples is a unit test for the wet bulb computation. The model on the top uses the accurate computation of the wet bulb temperature, whereas the model below uses the approximate computation of the wet bulb temperature.Extends from Modelica.Icons.Example (Icon for runnable examples).
Modelica definition
model TWetBul_TDryBulXi
extends Modelica.Icons.Example;
package Medium = Buildings.Media.Air "Medium model";
Modelica.Blocks.Sources.Ramp TDryBul(
height=10,
duration=1,
offset=273.15 + 30) "Dry bulb temperature";
Buildings.Utilities.Psychrometrics.TWetBul_TDryBulXi wetBul( redeclare
package Medium = Medium) "Model for wet bulb temperature";
Modelica.Blocks.Sources.Constant p(k=101325) "Pressure";
Modelica.Blocks.Sources.Ramp XHum(
duration=1,
height=(0.0133 - 0.0175),
offset=0.0175) "Humidity concentration";
Buildings.Utilities.Psychrometrics.TWetBul_TDryBulXi wetBulApp(redeclare
package Medium = Medium, approximateWetBulb=true)
"Model for wet bulb temperature";
equation
connect(p.y, wetBul.p);
connect(XHum.y, wetBul.Xi[1]);
connect(TDryBul.y, wetBul.TDryBul);
connect(p.y, wetBulApp.p);
connect(XHum.y, wetBulApp.Xi[1]);
connect(TDryBul.y, wetBulApp.TDryBul);
end TWetBul_TDryBulXi;
Buildings.Utilities.Psychrometrics.Examples.TotalAirDryAir
Unit test for conversion of humidity per total air and dry air mass
Information
Extends from Modelica.Icons.Example (Icon for runnable examples).
Modelica definition
model TotalAirDryAir
"Unit test for conversion of humidity per total air and dry air mass"
extends Modelica.Icons.Example;
package Medium = Buildings.Media.Air "Medium model";
Modelica.Blocks.Sources.Ramp XHum(
duration=1,
height=(0.01 - 0.1),
offset=0.1) "Humidity concentration";
ToTotalAir toTotalAir;
ToDryAir toDryAir;
Diagnostics.AssertEquality assertEquality(threShold=1E-5)
"Checks that model and its inverse implementation are correct";
equation
connect(toTotalAir.XiDry, XHum.y);
connect(toTotalAir.XiTotalAir, toDryAir.XiTotalAir);
connect(toDryAir.XiDry, assertEquality.u1);
connect(assertEquality.u2, XHum.y);
end TotalAirDryAir;
Buildings.Utilities.Psychrometrics.Examples.TWetBul_TDryBulPhi.Assertions
Information
Extends from Modelica.Blocks.Icons.Block (Basic graphical layout of input/output block).
Connectors
| Type | Name | Description |
|---|---|---|
| input RealInput | phi | Relative humidity |
| input RealInput | wetBulPhi_TWetBul | Wet bulb temperature from wetBulPhi_phi |
| input RealInput | wetBulXi_TWetBul | Wet bulb temperature from wetBulXi_phi |
Modelica definition
block Assertions
extends Modelica.Blocks.Icons.Block;
constant Modelica.SIunits.Temperature dT_max=0.1
"Maximum allowed deviation with reference result";
Modelica.Blocks.Interfaces.RealInput phi "Relative humidity";
Modelica.Blocks.Interfaces.RealInput wetBulPhi_TWetBul
"Wet bulb temperature from wetBulPhi_phi";
Modelica.Blocks.Interfaces.RealInput wetBulXi_TWetBul
"Wet bulb temperature from wetBulXi_phi";
equation
// Validation of one data point based on example 17.1 in
// Ananthanarayanan, P. N. Basic refrigeration and air conditioning. Tata McGraw-Hill Education, 2013.
if abs(phi-0.48)<0.001 then
assert(abs(wetBulPhi_TWetBul - 21.1-273.15) < dT_max,
"Error in computation of wet bulb temperature, deviation with reference result is larger than "
+ String(dT_max) + " K since the wet bulb temperature equals " +String(wetBulPhi_TWetBul));
end if;
assert(abs(wetBulPhi_TWetBul-wetBulXi_TWetBul)<1e-2, "Inconsistent implementation of wetBulPhi and wetBulXi.");
end Assertions;