Buildings.BoundaryConditions.SolarGeometry.BaseClasses

Information

This package contains base classes that are used to construct the models in Buildings.BoundaryConditions.SolarGeometry.

Extends from Modelica.Icons.BasesPackage (Icon for packages containing base classes).

Package Content

Name	Description
Declination	Declination angle
IncidenceAngle	The solar incidence angle on a tilted surface
SolarAzimuth	Solar azimuth
SolarHourAngle	Solar hour angle
ZenithAngle	Zenith angle
Examples	Collection of models that illustrate model use and test models

Buildings.BoundaryConditions.SolarGeometry.BaseClasses.Declination

Information

This component computes the angle between the equatorial plane and the solar beam.

Extends from Modelica.Blocks.Interfaces.BlockIcon (Basic graphical layout of input/output block).

Connectors

Type	Name	Description
input RealInput	nDay	One-based day number in seconds [s]
output RealOutput	decAng	Declination angle [rad]

Modelica definition

block Declination "Declination angle"
  extends Modelica.Blocks.Interfaces.BlockIcon;
public 
  Modelica.Blocks.Interfaces.RealInput nDay(quantity="Time", unit="s") 
    "One-based day number in seconds";
  Modelica.Blocks.Interfaces.RealOutput decAng(
    final quantity="Angle",
    final unit="rad",
    displayUnit="deg") "Declination angle";
equation 
  decAng = Modelica.Math.asin(-sin(23.45*2*Modelica.Constants.pi/360)*
    Modelica.Math.cos((nDay/86400 + 10)*2*Modelica.Constants.pi/365.25)) 
    "(A4.5)";
end Declination;

Buildings.BoundaryConditions.SolarGeometry.BaseClasses.IncidenceAngle

Information

This component computes the solar incidence angle on a tilted surface using the solar hour angle and the declination angle as input.

Extends from Modelica.Blocks.Interfaces.BlockIcon (Basic graphical layout of input/output block).

Parameters

Type	Name	Default	Description
Angle	lat		Latitude [rad]
Angle	azi		Surface azimuth. azi=-90 degree if surface outward unit normal points toward east; azi=0 if it points toward south [rad]
Angle	til		Surface tilt. til=90 degree for walls; til=0 for ceilings; til=180 for roof [rad]

Connectors

Type	Name	Description
input RealInput	solHouAng	Solar hour angle [rad]
input RealInput	decAng	Declination [rad]
output RealOutput	incAng	Incidence angle on a tilted surfce [rad]

Modelica definition

block IncidenceAngle "The solar incidence angle on a tilted surface"
  extends Modelica.Blocks.Interfaces.BlockIcon;
public 
  parameter Modelica.SIunits.Angle lat "Latitude";
  parameter Modelica.SIunits.Angle azi(displayUnit="degree") 
    "Surface azimuth. azi=-90 degree if surface outward unit normal points toward east; azi=0 if it points toward south";
  parameter Modelica.SIunits.Angle til(displayUnit="degree") 
    "Surface tilt. til=90 degree for walls; til=0 for ceilings; til=180 for roof";
  Modelica.Blocks.Interfaces.RealInput solHouAng(quantity="Angle", unit="rad") 
    "Solar hour angle";
  Modelica.Blocks.Interfaces.RealInput decAng(quantity="Angle", unit="rad") 
    "Declination";
  Modelica.Blocks.Interfaces.RealOutput incAng(
    final quantity="Angle",
    final unit="rad",
    displayUnit="deg") "Incidence angle on a tilted surfce";
protected 
  Real dec_c=Modelica.Math.cos(decAng);
  Real dec_s=Modelica.Math.sin(decAng);
  Real sol_c=Modelica.Math.cos(solHouAng);
  Real sol_s=Modelica.Math.sin(solHouAng);
  Real lat_c=Modelica.Math.cos(lat);
  Real lat_s=Modelica.Math.sin(lat);
equation 
  incAng = Modelica.Math.acos(Modelica.Math.cos(til)*(dec_c*sol_c*lat_c + dec_s
    *lat_s) + Modelica.Math.sin(til)*(Modelica.Math.sin(azi)*dec_c*sol_s +
    Modelica.Math.cos(azi)*(dec_c*sol_c*lat_s - dec_s*lat_c))) "(A.4.13)";
end IncidenceAngle;

Buildings.BoundaryConditions.SolarGeometry.BaseClasses.SolarAzimuth

Information

This component computes the solar azimuth angle.

Extends from Modelica.Blocks.Interfaces.BlockIcon (Basic graphical layout of input/output block).

Parameters

Type	Name	Default	Description
Angle	lat		Latitude [rad]

Connectors

Type	Name	Description
input RealInput	zen	Zenith angle [rad]
input RealInput	solTim	Solar time [s]
output RealOutput	solAzi	Solar Azimuth [rad]
input RealInput	decAng	Decline angle [rad]

Modelica definition

block SolarAzimuth "Solar azimuth"
  extends Modelica.Blocks.Interfaces.BlockIcon;
public 
  parameter Modelica.SIunits.Angle lat "Latitude";
  Modelica.Blocks.Interfaces.RealInput zen(quantity="Angle", unit="rad") 
    "Zenith angle";
  Modelica.Blocks.Interfaces.RealInput solTim(quantity="Time", unit="s") 
    "Solar time";
  Modelica.Blocks.Interfaces.RealOutput solAzi(
    final quantity="Angle",
    final unit="rad",
    displayUnit="deg") "Solar Azimuth";
  Modelica.Blocks.Interfaces.RealInput decAng(quantity="Angle", unit="rad") 
    "Decline angle";

protected 
Real arg;
Real tmp;

algorithm 
  tmp :=(Modelica.Math.sin(lat)*Modelica.Math.cos(zen) - Modelica.Math.sin(
    decAng))/(Modelica.Math.cos(lat)*Modelica.Math.sin(zen));

  arg :=min(1.0, max(-1.0, tmp));

  if solTim < 43200 then
    solAzi :=-Modelica.Math.acos(arg);
  else
    solAzi := Modelica.Math.acos(arg);
  end if "(A4.9a and b)";
end SolarAzimuth;

Buildings.BoundaryConditions.SolarGeometry.BaseClasses.SolarHourAngle

Information

This component computes the solar hour angle, which is defined as the angle between the circle that passes through an observer, the north pole and the south pole, and the circle that passes through the sun, the north and the south pole.

Extends from Modelica.Blocks.Interfaces.BlockIcon (Basic graphical layout of input/output block).

Connectors

Type	Name	Description
input RealInput	solTim	Solar time [s]
output RealOutput	solHouAng	Solar hour angle [rad]

Modelica definition

block SolarHourAngle "Solar hour angle"
  extends Modelica.Blocks.Interfaces.BlockIcon;
public 
  Modelica.Blocks.Interfaces.RealInput solTim(quantity="Time", unit="s") 
    "Solar time";
  Modelica.Blocks.Interfaces.RealOutput solHouAng(
    final quantity="Angle",
    final unit="rad",
    displayUnit="deg") "Solar hour angle";
equation 
  solHouAng = (solTim/3600 - 12)*2*Modelica.Constants.pi/24 
    "Our unit is s instead of h in (A4.6)";
end SolarHourAngle;

Buildings.BoundaryConditions.SolarGeometry.BaseClasses.ZenithAngle

Information

This component computes the zenith angle, which is the angle between the earth surface normal and the sun's beam. Input are the solar hour angle and the declination angle.

Extends from Modelica.Blocks.Interfaces.BlockIcon (Basic graphical layout of input/output block).

Parameters

Type	Name	Default	Description
Angle	lat		Latitude [rad]

Connectors

Type	Name	Description
input RealInput	solHouAng	Solar hour angle [rad]
input RealInput	decAng	Declination [rad]
output RealOutput	zen	Zenith angle [rad]

Modelica definition

block ZenithAngle "Zenith angle"
  extends Modelica.Blocks.Interfaces.BlockIcon;
public 
  parameter Modelica.SIunits.Angle lat "Latitude";
  Modelica.Blocks.Interfaces.RealInput solHouAng(quantity="Angle", unit="rad") 
    "Solar hour angle";
  Modelica.Blocks.Interfaces.RealInput decAng(quantity="Angle", unit="rad") 
    "Declination";
  Modelica.Blocks.Interfaces.RealOutput zen(
    final quantity="Angle",
    final unit="rad",
    displayUnit="deg") "Zenith angle";
equation 
  zen =  Modelica.Math.acos(Modelica.Math.cos(lat)*Modelica.Math.cos(decAng)*
    Modelica.Math.cos(solHouAng) + Modelica.Math.sin(lat)*Modelica.Math.sin(
    decAng)) "(A4.8)";
end ZenithAngle;