Buildings.Airflow.Multizone.BaseClasses.Examples

Information

This package contains examples for the use of models that can be found in Buildings.Airflow.Multizone.BaseClasses.

Package Content

Name	Description
PowerLaw	Test model for power law function
PowerLawFixedM	Test model for power law function
WindPressureLowRise	Test model for wind pressure function

Buildings.Airflow.Multizone.BaseClasses.Examples.PowerLaw

Information

This examples demonstrates the Buildings.Airflow.Multizone.BaseClasses.powerLaw function.

Parameters

Type	Name	Default	Description
Real	k	2/10^m	Flow coefficient, k = V_flow/ dp^m
Real	m	0.5	Flow exponent, m=0.5 for turbulent, m=1 for laminar
Pressure	dp_turbulent	5	Pressure difference where regularization starts [Pa]

Modelica definition

model PowerLaw "Test model for power law function"
  extends Modelica.Icons.Example;
  parameter Real k = 2/10^m "Flow coefficient, k = V_flow/ dp^m";

  parameter Real m(min=0.5, max=1) = 0.5 
    "Flow exponent, m=0.5 for turbulent, m=1 for laminar";
  parameter Modelica.SIunits.Pressure dp_turbulent(min=0)=5 
    "Pressure difference where regularization starts";

  Modelica.SIunits.Pressure dp "Pressure difference";
  Modelica.SIunits.VolumeFlowRate V_flow "Volume flow rate";
equation 
  dp = 10*(-1+2*time);
  V_flow = Buildings.Airflow.Multizone.BaseClasses.powerLaw(dp=dp, k=k, m=m, dp_turbulent=dp_turbulent);
end PowerLaw;

Buildings.Airflow.Multizone.BaseClasses.Examples.PowerLawFixedM

Information

This examples demonstrates the Buildings.Airflow.Multizone.BaseClasses.powerLaw and Buildings.Airflow.Multizone.BaseClasses.powerLawFixedM functions. They need to return the same function value. This is verified by an assert statement.

Parameters

Type	Name	Default	Description
Real	k	2/10^m	Flow coefficient, k = V_flow/ dp^m
Pressure	dp_turbulent	5	Pressure difference where regularization starts [Pa]

Modelica definition

model PowerLawFixedM "Test model for power law function"
  extends Modelica.Icons.Example;
  parameter Real k = 2/10^m "Flow coefficient, k = V_flow/ dp^m";

  constant Real m(min=0.5, max=1) = 0.5 
    "Flow exponent, m=0.5 for turbulent, m=1 for laminar";
  parameter Modelica.SIunits.Pressure dp_turbulent(min=0)=5 
    "Pressure difference where regularization starts";

  Modelica.SIunits.Pressure dp "Pressure difference";
  Modelica.SIunits.VolumeFlowRate V_flow 
    "Volume flow rate computed with model powerLaw";
  Modelica.SIunits.VolumeFlowRate VFixed_flow 
    "Volume flow rate computed with model powerLawFixed";

  constant Real gamma(min=1) = 1.5 
    "Normalized flow rate where dphi(0)/dpi intersects phi(1)";
  constant Real a = gamma 
    "Polynomial coefficient for regularized implementation of flow resistance";
  constant Real b = 1/8*m^2 - 3*gamma - 3/2*m + 35.0/8 
    "Polynomial coefficient for regularized implementation of flow resistance";
  constant Real c = -1/4*m^2 + 3*gamma + 5/2*m - 21.0/4 
    "Polynomial coefficient for regularized implementation of flow resistance";
  constant Real d = 1/8*m^2 - gamma - m + 15.0/8 
    "Polynomial coefficient for regularized implementation of flow resistance";

equation 
  dp = 10*(-1+2*time);
  V_flow = Buildings.Airflow.Multizone.BaseClasses.powerLaw(dp=dp, k=k, m=m, dp_turbulent=dp_turbulent);
  VFixed_flow = Buildings.Airflow.Multizone.BaseClasses.powerLawFixedM(
    k=k,
    dp=dp,
    m=m,
    a=a,
    b=b,
    c=c,
    d=d,
    dp_turbulent=dp_turbulent);
  assert(abs(V_flow-VFixed_flow) < 1E-10, "Error: The two implementations of the power law model need to give identical results");
end PowerLawFixedM;

Buildings.Airflow.Multizone.BaseClasses.Examples.WindPressureLowRise

Information

This examples demonstrates the Buildings.Airflow.Multizone.BaseClasses.windPressureLowRise function.

Parameters

Type	Name	Default	Description
Real	Cp0	0.6	Wind pressure coefficient for normal wind incidence angle
Real	G	Modelica.Math.log(0.5)	Natural logarithm of side ratio

Modelica definition

model WindPressureLowRise "Test model for wind pressure function"
  extends Modelica.Icons.Example;
  parameter Real Cp0 = 0.6 
    "Wind pressure coefficient for normal wind incidence angle";
  Modelica.SIunits.Angle incAng "Wind incidence angle (0: normal to wall)";
  parameter Real G = Modelica.Math.log(0.5) "Natural logarithm of side ratio";
  Real Cp "Wind pressure coefficient";
equation 
  incAng=time*2*Modelica.Constants.pi;
  Cp = Buildings.Airflow.Multizone.BaseClasses.windPressureLowRise(Cp0=Cp0, G=G, incAng=incAng);
end WindPressureLowRise;