Buildings.BoundaryConditions.SolarIrradiation

Information

Package Content

Name	Description
DiffuseIsotropic	Diffuse solar irradiation on a tilted surface with an isotropic sky model
DiffusePerez	Hemispherical diffuse irradiation on a tilted surface using Perez's anisotropic sky model
DirectTiltedSurface	Direct solar irradiation on a tilted surface
Examples	Collection of models that illustrate model use and test models
BaseClasses	Package with base classes for Buildings.BoundaryConditions.SolarIrradiation

Buildings.BoundaryConditions.SolarIrradiation.DiffuseIsotropic

Information

This component computes the hemispherical diffuse irradiation on a tilted surface using an isotropic model. The irradiation is a sum composed of diffuse solar irradiation and radiation reflected by the ground. For a definition of the parameters, see the User's Guide.

References

Parameters

Type	Name	Default	Description
Angle	til		Surface tilt [rad]
Real	rho	0.2	Ground reflectance
Boolean	outSkyCon	false	Output contribution of diffuse irradiation from sky
Boolean	outGroCon	false	Output contribution of diffuse irradiation from ground

Connectors

Type	Name	Description
output RealOutput	H	Radiation per unit area [W/m2]
Bus	weaBus	Bus with weather data
output RealOutput	HSkyDifTil	Diffuse solar irradiation on a tilted surfce from the sky
output RealOutput	HGroDifTil	Diffuse solar irradiation on a tilted surfce from the ground

Modelica definition

block DiffuseIsotropic 
  "Diffuse solar irradiation on a tilted surface with an isotropic sky model"
  extends Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.PartialSolarIrradiation;
public 
  parameter Real rho=0.2 "Ground reflectance";
  parameter Boolean outSkyCon=false 
    "Output contribution of diffuse irradiation from sky";
  parameter Boolean outGroCon=false 
    "Output contribution of diffuse irradiation from ground";

  Modelica.Blocks.Math.Add add;

  Modelica.Blocks.Interfaces.RealOutput HSkyDifTil if (outSkyCon) 
    "Diffuse solar irradiation on a tilted surfce from the sky";
  Modelica.Blocks.Interfaces.RealOutput HGroDifTil if (outGroCon) 
    "Diffuse solar irradiation on a tilted surfce from the ground";
protected 
  Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.DiffuseIsotropic
    HDifTilIso(til=til, rho=rho);

equation 
  connect(weaBus.HGloHor, HDifTilIso.HGloHor);
  connect(weaBus.HDifHor, HDifTilIso.HDifHor);

  connect(HDifTilIso.HSkyDifTil, add.u1);
  connect(HDifTilIso.HGroDifTil, add.u2);
  connect(add.y, H);

  connect(HDifTilIso.HSkyDifTil, HSkyDifTil);
  connect(HDifTilIso.HGroDifTil, HGroDifTil);
end DiffuseIsotropic;

Buildings.BoundaryConditions.SolarIrradiation.DiffusePerez

Information

This component computes the hemispherical diffuse irradiation on a tilted surface using an anisotropic sky model proposed by Perez. For a definition of the parameters, see the User's Guide.

References

• P. Ineichen, R. Perez and R. Seals (1987). The Importance of Correct Albedo Determination for Adequately Modeling Energy Received by Tilted Surface, Solar Energy, 39(4): 301-305.
• R. Perez, R. Seals, P. Ineichen, R. Stewart and D. Menicucci (1987). A New Simplified Version of the Perez Diffuse Irradiance Model for Tilted Surface, Solar Energy, 39(3): 221-231.
• R. Perez, P. Ineichen, R. Seals, J. Michalsky and R. Stewart (1990). Modeling Dyalight Availability and Irradiance Componets From Direct and Global Irradiance, Solar Energy, 44(5):271-289.

Parameters

Type	Name	Default	Description
Angle	til		Surface tilt [rad]
Real	rho	0.2	Ground reflectance
Angle	lat		Latitude [rad]
Angle	azi		Surface azimuth [rad]
Boolean	outSkyCon	false	Output contribution of diffuse irradiation from sky
Boolean	outGroCon	false	Output contribution of diffuse irradiation from ground

Connectors

Type	Name	Description
output RealOutput	H	Radiation per unit area [W/m2]
Bus	weaBus	Bus with weather data
output RealOutput	HSkyDifTil	Hemispherical diffuse solar irradiation on a tilted surfce from the sky
output RealOutput	HGroDifTil	Hemispherical diffuse solar irradiation on a tilted surfce from the ground

Modelica definition

block DiffusePerez 
  "Hemispherical diffuse irradiation on a tilted surface using Perez's anisotropic sky model"
  extends Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.PartialSolarIrradiation;

  parameter Real rho=0.2 "Ground reflectance";
  parameter Modelica.SIunits.Angle lat "Latitude";
  parameter Modelica.SIunits.Angle azi "Surface azimuth";
  parameter Boolean outSkyCon=false 
    "Output contribution of diffuse irradiation from sky";
  parameter Boolean outGroCon=false 
    "Output contribution of diffuse irradiation from ground";

  Modelica.Blocks.Math.Add add;
  Modelica.Blocks.Interfaces.RealOutput HSkyDifTil if (outSkyCon) 
    "Hemispherical diffuse solar irradiation on a tilted surfce from the sky";
  Modelica.Blocks.Interfaces.RealOutput HGroDifTil if (outGroCon) 
    "Hemispherical diffuse solar irradiation on a tilted surfce from the ground";

protected 
  BaseClasses.DiffusePerez HDifTil(final til=til, final rho=rho);
  BaseClasses.SkyClearness skyCle;
  BaseClasses.BrighteningCoefficient briCoe;
  BaseClasses.RelativeAirMass relAirMas;
  BaseClasses.SkyBrightness skyBri;
  SolarGeometry.IncidenceAngle incAng(
    lat=lat,
    azi=azi,
    til=til);

equation 
  connect(relAirMas.relAirMas, skyBri.relAirMas);
  connect(skyBri.skyBri, briCoe.skyBri);
  connect(skyCle.skyCle, briCoe.skyCle);
  connect(incAng.y, HDifTil.incAng);
  connect(weaBus.sol.zen, skyCle.zen);
  connect(weaBus.sol.zen, relAirMas.zen);
  connect(weaBus.sol.zen, briCoe.zen);
  connect(weaBus.HGloHor, skyCle.HGloHor);
  connect(weaBus.HDifHor, skyCle.HDifHor);
  connect(weaBus.HDifHor, skyBri.HDifHor);
  connect(weaBus.HGloHor, HDifTil.HGloHor);
  connect(weaBus.HDifHor, HDifTil.HDifHor);

  connect(briCoe.F2, HDifTil.briCof2);
  connect(briCoe.F1, HDifTil.briCof1);
  connect(weaBus, incAng.weaBus);
  connect(weaBus.sol.zen, HDifTil.zen);
  connect(HDifTil.HSkyDifTil, add.u1);
  connect(HDifTil.HGroDifTil, add.u2);
  connect(add.y, H);

  connect(HDifTil.HSkyDifTil, HSkyDifTil);
  connect(HDifTil.HGroDifTil, HGroDifTil);
end DiffusePerez;

Buildings.BoundaryConditions.SolarIrradiation.DirectTiltedSurface

Information

This component computes the direct solar irradiation on a tilted surface. For a definition of the parameters, see the User's Guide.

Parameters

Type	Name	Default	Description
Angle	til		Surface tilt [rad]
Angle	lat		Latitude [rad]
Angle	azi		Surface azimuth [rad]

Connectors

Type	Name	Description
output RealOutput	H	Radiation per unit area [W/m2]
Bus	weaBus	Bus with weather data
output RealOutput	inc	Incidence angle [rad]

Modelica definition

block DirectTiltedSurface 
  "Direct solar irradiation on a tilted surface"
  extends Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.PartialSolarIrradiation;

  parameter Modelica.SIunits.Angle lat "Latitude";
  parameter Modelica.SIunits.Angle azi "Surface azimuth";

  Buildings.BoundaryConditions.WeatherData.Bus weaBus;

  Modelica.Blocks.Interfaces.RealOutput inc(
    final quantity="Angle",
    final unit="rad",
    displayUnit="deg") "Incidence angle";

protected 
  SolarGeometry.IncidenceAngle incAng(
    final azi=azi,
    final til=til,
    final lat=lat);
  Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.DirectTiltedSurface
    HDirTil;

equation 
  connect(incAng.y, HDirTil.incAng);

  connect(weaBus.HDirNor, HDirTil.HDirNor);
  connect(incAng.y, inc);
  connect(HDirTil.HDirTil, H);

  connect(weaBus, incAng.weaBus);
end DirectTiltedSurface;