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Buildings.BoundaryConditions.SolarIrradiation.BaseClasses

Package with base classes for Buildings.BoundaryConditions.SolarIrradiation

Information

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

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

Package Content

Name Description
Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.BrighteningCoefficient BrighteningCoefficient Circumsolar and horizon brightening coefficients
Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.DiffuseIsotropic DiffuseIsotropic Diffuse solar irradiation on a tilted surface with an isotropic model
Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.DiffusePerez DiffusePerez Hemispherical diffuse irradiation on a tilted surface with Perez's anisotropic model
Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.DirectTiltedSurface DirectTiltedSurface Direct solar irradiation on a tilted surface
Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.RelativeAirMass RelativeAirMass Relative air mass
Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.SkyBrightness SkyBrightness Sky brightness
Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.SkyClearness SkyClearness Sky clearness
Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.PartialSolarIrradiation PartialSolarIrradiation Partial model that is used to compute the direct and diffuse solar irradiation
Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.Examples Examples Collection of models that illustrate model use and test models

Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.BrighteningCoefficient Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.BrighteningCoefficient

Circumsolar and horizon brightening coefficients

Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.BrighteningCoefficient

Information

This component computes the circumsolar and horizon brightening coefficients. 



Extends from Modelica.Blocks.Icons.Block (Basic graphical layout of input/output block).


Connectors




TypeNameDescription


input RealInputzenZenith angle of the sun beam [rad]


input RealInputskyCleSky clearness. skyCle=1: overcast sky; skyCle=8 clear sky


input RealInputskyBriSky brightness [0,1]


output RealOutputF1Circumsolar brightening coefficient


output RealOutputF2Horizon brightening coefficient




Modelica definition


block BrighteningCoefficient 
  "Circumsolar and horizon brightening coefficients"
  extends Modelica.Blocks.Icons.Block;
  import H = Buildings.Utilities.Math.Functions.spliceFunction;
public 
  Modelica.Blocks.Interfaces.RealInput zen(
    quantity="Angle",
    unit="rad",
    displayUnit="degree") "Zenith angle of the sun beam";
  Modelica.Blocks.Interfaces.RealInput skyCle 
    "Sky clearness. skyCle=1: overcast sky; skyCle=8 clear sky";
  Modelica.Blocks.Interfaces.RealInput skyBri "Sky brightness [0,1]";
  Modelica.Blocks.Interfaces.RealOutput F1 
    "Circumsolar brightening coefficient";
  Modelica.Blocks.Interfaces.RealOutput F2 "Horizon brightening coefficient";
protected 
  Real F11;
  Real F12;
  Real F13;
  Real F21;
  Real F22;
  Real F23;
  Real d=0.01;
  Real a1;
  Real a2;
  Real a3;
  Real a4;
  Real a5;
  Real a6;
  Real a7;
  Real a8;
  Real b1;
  Real b2;
  Real b3;
  Real b4;
  Real b5;
  Real b6;
  Real b7;
  Real b8;
equation 
  b1 = H(
    1,
    0,
    1.065 - skyCle,
    d);
  b2 = H(
    1,
    0,
    1.23 - skyCle,
    d);
  b3 = H(
    1,
    0,
    1.50 - skyCle,
    d);
  b4 = H(
    1,
    0,
    1.95 - skyCle,
    d);
  b5 = H(
    1,
    0,
    2.80 - skyCle,
    d);

  b6 = H(
    1,
    0,
    4.50 - skyCle,
    d);
  b7 = H(
    1,
    0,
    6.20 - skyCle,
    d);
  b8 = H(
    1,
    0,
    skyCle - 6.20,
    d);

  a1 = b1;
  a2 = b2 - b1;
  a3 = b3 - b2;
  a4 = b4 - b3;
  a5 = b5 - b4;
  a6 = b6 - b5;
  a7 = b7 - b6;
  a8 = b8;

  F11 = -0.0083117*a1 + 0.1299457*a2 + 0.3296958*a3 + 0.5682053*a4 + 0.8730280*
    a5 + 1.1326077*a6 + 1.0601591*a7 + 0.6777470*a8;
  F12 = 0.5877285*a1 + 0.6825954*a2 + 0.4868735*a3 + 0.1874525*a4 - 0.3920403*
    a5 - 1.2367284*a6 - 1.5999137*a7 - 0.3272588*a8;
  F13 = -0.0620636*a1 - 0.1513725*a2 - 0.2210958*a3 - 0.2951290*a4 - 0.3616149*
    a5 - 0.4118494*a6 - 0.3589221*a7 - 0.2504286*a8;
  F21 = -0.0596012*a1 - 0.0189325*a2 + 0.0554140*a3 + 0.1088631*a4 + 0.2255647*
    a5 + 0.2877813*a6 + 0.2642124*a7 + 0.1561313*a8;
  F22 = 0.0721249*a1 + 0.0659650*a2 - 0.0639588*a3 - 0.1519229*a4 - 0.4620442*
    a5 - 0.8230357*a6 - 1.1272340*a7 - 1.3765031*a8;
  F23 = -0.0220216*a1 - 0.0288748*a2 - 0.0260542*a3 - 0.0139754*a4 + 0.0012448*
    a5 + 0.0558651*a6 + 0.1310694*a7 + 0.2506212*a8;
  F1 = Buildings.Utilities.Math.Functions.smoothMax(
    0,
    F11 + F12*skyBri + F13*zen,
    0.01);
  F2 = F21 + F22*skyBri + F23*zen;
end BrighteningCoefficient;







Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.DiffuseIsotropic
Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.DiffuseIsotropic



Diffuse solar irradiation on a tilted surface with an isotropic model



Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.DiffuseIsotropic



Information




This component computes the hemispherical diffuse irradiation on a tilted surface.
The irradiation is composed of the diffuse horizontal solar irradiation and the irradiation
that has been reflected by the ground. Both components are adjusted to take into account
the tilt of the receiving surface.



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.



Extends from Modelica.Blocks.Icons.Block (Basic graphical layout of input/output block).


Parameters




TypeNameDefaultDescription


Realrho0.2Ground reflectance


Angletil Surface tilt angle [rad]




Connectors




TypeNameDescription


input RealInputHDifHorHorizontal diffuse solar radiation [W/m2]


input RealInputHGloHorHorizontal global radiation [W/m2]


output RealOutputHGroDifTilDiffuse solar irradiation on a tilted surfce from the ground [W/m2]


output RealOutputHSkyDifTilDiffuse solar irradiation on a tilted surfce from the sky [W/m2]




Modelica definition


block DiffuseIsotropic 
  "Diffuse solar irradiation on a tilted surface with an isotropic model"
  extends Modelica.Blocks.Icons.Block;
public 
  parameter Real rho=0.2 "Ground reflectance";
  parameter Modelica.SIunits.Angle til(displayUnit="deg") "Surface tilt angle";

  Modelica.Blocks.Interfaces.RealInput HDifHor(quantity=
        "RadiantEnergyFluenceRate", unit="W/m2") 
    "Horizontal diffuse solar radiation";
  Modelica.Blocks.Interfaces.RealInput HGloHor(quantity=
        "RadiantEnergyFluenceRate", unit="W/m2") "Horizontal global radiation";

  Modelica.Blocks.Interfaces.RealOutput HGroDifTil(final quantity="RadiantEnergyFluenceRate",
      final unit="W/m2") 
    "Diffuse solar irradiation on a tilted surfce from the ground";
protected 
  Real til_c "Cosine of tilt angle";

public 
  Modelica.Blocks.Interfaces.RealOutput HSkyDifTil(final quantity="RadiantEnergyFluenceRate",
      final unit="W/m2") 
    "Diffuse solar irradiation on a tilted surfce from the sky";
equation 
  til_c = Modelica.Math.cos(til);
  HSkyDifTil = 0.5*HDifHor*(1 + til_c);
  HGroDifTil = 0.5*HGloHor*rho*(1 - til_c);
end DiffuseIsotropic;







Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.DiffusePerez
Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.DiffusePerez



Hemispherical diffuse irradiation on a tilted surface with Perez's anisotropic model



Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.DiffusePerez



Information




This component computes the hemispherical diffuse irradiation on a tilted surface by using an anisotropic model proposed by Perez. 



References





Extends from Modelica.Blocks.Icons.Block (Basic graphical layout of input/output block).


Parameters




TypeNameDefaultDescription


Realrho0.2Ground reflectance


Angletil Surface tilt angle [rad]




Connectors




TypeNameDescription


input RealInputbriCof1Brightening Coeffcient F1


input RealInputbriCof2Brightening Coeffcient F2


input RealInputHDifHorDiffuse horizontal solar radiation [W/m2]


input RealInputHGloHorGlobal horizontal radiation [W/m2]


input RealInputzenZenith angle of the sun beam [rad]


input RealInputincAngSolar incidence angle on the surface [rad]


output RealOutputHGroDifTilHemispherical diffuse solar irradiation on a tilted surfce from the ground [W/m2]


output RealOutputHSkyDifTilHemispherical diffuse solar irradiation on a tilted surfce from the sky [W/m2]




Modelica definition


block DiffusePerez 
  "Hemispherical diffuse irradiation on a tilted surface with Perez's anisotropic model"
  extends Modelica.Blocks.Icons.Block;
public 
  parameter Real rho=0.2 "Ground reflectance";
  parameter Modelica.SIunits.Angle til(displayUnit="deg") "Surface tilt angle";
  Modelica.Blocks.Interfaces.RealInput briCof1 "Brightening Coeffcient F1";
  Modelica.Blocks.Interfaces.RealInput briCof2 "Brightening Coeffcient F2";
  Modelica.Blocks.Interfaces.RealInput HDifHor(quantity=
        "RadiantEnergyFluenceRate", unit="W/m2") 
    "Diffuse horizontal solar radiation";
  Modelica.Blocks.Interfaces.RealInput HGloHor(quantity=
        "RadiantEnergyFluenceRate", unit="W/m2") "Global horizontal radiation";

  Modelica.Blocks.Interfaces.RealInput zen(
    quantity="Angle",
    unit="rad",
    displayUnit="degree") "Zenith angle of the sun beam";
  Modelica.Blocks.Interfaces.RealInput incAng(
    quantity="Angle",
    unit="rad",
    displayUnit="degree") "Solar incidence angle on the surface";

  Modelica.Blocks.Interfaces.RealOutput HGroDifTil(final quantity=
        "RadiantEnergyFluenceRate", final unit="W/m2") 
    "Hemispherical diffuse solar irradiation on a tilted surfce from the ground";
  Modelica.Blocks.Interfaces.RealOutput HSkyDifTil(final quantity=
        "RadiantEnergyFluenceRate", final unit="W/m2") 
    "Hemispherical diffuse solar irradiation on a tilted surfce from the sky";
protected 
  Real a;
  Real b;
  constant Real bMin=Modelica.Math.cos(Modelica.Constants.pi*85/180) 
    "Lower bound for b";
equation 
  a = Buildings.Utilities.Math.Functions.smoothMax(
    0,
    Modelica.Math.cos(incAng),
    0.01);
  b = Buildings.Utilities.Math.Functions.smoothMax(
    bMin,
    Modelica.Math.cos(zen),
    0.01);
  HSkyDifTil = HDifHor*(0.5*(1 - briCof1)*(1 + Modelica.Math.cos(til)) +
    briCof1*a/b + briCof2*Modelica.Math.sin(til));
  HGroDifTil = HGloHor*0.5*rho*(1 - Modelica.Math.cos(til));

end DiffusePerez;







Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.DirectTiltedSurface
Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.DirectTiltedSurface



Direct solar irradiation on a tilted surface



Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.DirectTiltedSurface



Information




This component computes the direct solar irradiation on a tilted surface.





Extends from Modelica.Blocks.Icons.Block (Basic graphical layout of input/output block).


Connectors




TypeNameDescription


input RealInputincAngIncidence angle of the sun beam on a tilted surface [rad]


input RealInputHDirNorDirect normal radiation [W/m2]


output RealOutputHDirTilDirect solar irradiation on a tilted surfce [W/m2]




Modelica definition


block DirectTiltedSurface 
  "Direct solar irradiation on a tilted surface"
  extends Modelica.Blocks.Icons.Block;
  Modelica.Blocks.Interfaces.RealInput incAng(
    quantity="Angle",
    unit="rad",
    displayUnit="degree") "Incidence angle of the sun beam on a tilted surface";
  Modelica.Blocks.Interfaces.RealInput HDirNor(quantity=
        "RadiantEnergyFluenceRate", unit="W/m2") "Direct normal radiation";
  Modelica.Blocks.Interfaces.RealOutput HDirTil(final quantity=
        "RadiantEnergyFluenceRate", final unit="W/m2") 
    "Direct solar irradiation on a tilted surfce";

algorithm 
  HDirTil := max(0, Modelica.Math.cos(incAng)*HDirNor);
end DirectTiltedSurface;







Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.RelativeAirMass
Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.RelativeAirMass



Relative air mass



Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.RelativeAirMass



Information




This component computes the relative air mass for sky brightness.



References

R. Perez (1999).
Fortran Function irrpz.f,
Emailed by R. Perez to F.C. Winkelmann on May 21, 1999.




Extends from Modelica.Blocks.Icons.Block (Basic graphical layout of input/output block).


Connectors




TypeNameDescription


input RealInputzenZenith angle of the sun beam [rad]


output RealOutputrelAirMasRelative air mass




Modelica definition


block RelativeAirMass "Relative air mass"
  extends Modelica.Blocks.Icons.Block;
public 
  Modelica.Blocks.Interfaces.RealInput zen(
    quantity="Angle",
    unit="rad",
    displayUnit="degree") "Zenith angle of the sun beam";
  Modelica.Blocks.Interfaces.RealOutput relAirMas "Relative air mass";
protected 
  Real zenLim;
  Real zenDeg;
equation 
  zenLim = Buildings.Utilities.Math.Functions.smoothMin(
    zen,
    Modelica.Constants.pi/2,
    0.01);
  zenDeg = zenLim*180/Modelica.Constants.pi;
  relAirMas = 1/(Modelica.Math.cos(zenLim) + 0.15*(93.9 - zenDeg)^(-1.253));
end RelativeAirMass;







Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.SkyBrightness
Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.SkyBrightness



Sky brightness



Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.SkyBrightness



Information




This component computes the sky brightness.



References

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.



Extends from Modelica.Blocks.Icons.Block (Basic graphical layout of input/output block).


Connectors




TypeNameDescription


input RealInputrelAirMasRelative Air Mass


input RealInputHDifHorHorizontal diffuse solar radiation [W/m2]


output RealOutputskyBriSky Brightness




Modelica definition


block SkyBrightness "Sky brightness"
  extends Modelica.Blocks.Icons.Block;
public 
  Modelica.Blocks.Interfaces.RealInput relAirMas "Relative Air Mass";
  Modelica.Blocks.Interfaces.RealInput HDifHor(quantity=
        "RadiantEnergyFluenceRate", unit="W/m2") 
    "Horizontal diffuse solar radiation";
  Modelica.Blocks.Interfaces.RealOutput skyBri "Sky Brightness";
equation 
  skyBri = Buildings.Utilities.Math.Functions.smoothMin(
    HDifHor*relAirMas/1367,
    1,
    0.025);
end SkyBrightness;







Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.SkyClearness
Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.SkyClearness



Sky clearness



Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.SkyClearness



Information




This component computes the sky clearness.





Extends from Modelica.Blocks.Icons.Block (Basic graphical layout of input/output block).


Connectors




TypeNameDescription


input RealInputzenZenith angle of the sun beam [rad]


input RealInputHDifHorHorizontal diffuse solar radiation [W/m2]


input RealInputHGloHorHorizontal global solar radiation [W/m2]


output RealOutputskyCleSky clearness. skyCle=1: overast sky; skyCle=8: clear sky




Modelica definition


block SkyClearness "Sky clearness"
  extends Modelica.Blocks.Icons.Block;
public 
  Modelica.Blocks.Interfaces.RealInput zen(
    quantity="Angle",
    unit="rad",
    displayUnit="degreeC") "Zenith angle of the sun beam";
  Modelica.Blocks.Interfaces.RealInput HDifHor(quantity=
        "RadiantEnergyFluenceRate", unit="W/m2") 
    "Horizontal diffuse solar radiation";
  Modelica.Blocks.Interfaces.RealInput HGloHor(quantity=
        "RadiantEnergyFluenceRate", unit="W/m2") 
    "Horizontal global solar radiation";
  Modelica.Blocks.Interfaces.RealOutput skyCle 
    "Sky clearness. skyCle=1: overast sky; skyCle=8: clear sky";
protected 
  Real tmp1;
algorithm 
  tmp1 := 5.534e-6*(zen*180/Modelica.Constants.pi)^3;

  skyCle := smooth(1, if (HGloHor < Modelica.Constants.small) then 1 else 
    Buildings.Utilities.Math.Functions.smoothLimit(
    (HGloHor/Buildings.Utilities.Math.Functions.smoothMax(
      HDifHor,
      1e-4,
      1e-5) + tmp1)/(1 + tmp1),
    1,
    8,
    0.1));
end SkyClearness;







Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.PartialSolarIrradiation
Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.PartialSolarIrradiation



Partial model that is used to compute the direct and diffuse solar irradiation



Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.PartialSolarIrradiation



Information




This is a partial model that is used to implement the direct and diffuse irradiation.





Extends from Modelica.Blocks.Icons.Block (Basic graphical layout of input/output block).


Parameters




TypeNameDefaultDescription


Angletil Surface tilt [rad]




Connectors




TypeNameDescription


output RealOutputHRadiation per unit area [W/m2]


BusweaBusBus with weather data




Modelica definition


partial block PartialSolarIrradiation 
  "Partial model that is used to compute the direct and diffuse solar irradiation"
  extends Modelica.Blocks.Icons.Block;
  parameter Modelica.SIunits.Angle til(displayUnit="deg") "Surface tilt";
  Modelica.Blocks.Interfaces.RealOutput H(
     final quantity="RadiantEnergyFluenceRate",
     final unit="W/m2") "Radiation per unit area";

  WeatherData.Bus weaBus "Bus with weather data";

end PartialSolarIrradiation;






Automatically generated Thu Jun 19 10:54:29 2014.