modelFLUXsurf
Information
Calculation of diffuse and direct incident irradiance on a particular surface (tilt and azimuth given)
Hypothesis and equations
In the diffuse isotropic model, the total irradiance on an particular surface is given by:
In the HDKR (Hay, Davies, Klucher, Reindl) model, the total radiation on an inclined surface is given by:
where:
,
,
where n is the calendar day (day number within the month) and Isc the solar constant (in this model Isc = 1367 W / m²).
Bibliography
none
Instructions for use
Model which takes as input the vector G from a weather reader to calculate the surface irradiance on a particular surface (tilt and orientation given). G contains:
- (1) Horizontal diffuse flux
- (2) Normal direct flux
- (3) Horizontal direct flux
- (4) Horizontal global flux
- (5) Time in UTC at time t = 0 (start of the simulation)
- (6-7-8) Sun's direction cosines (6-sinH, 7-cosW, 8-cosS)
- (9) Solar azimuth angle
- (10) Solar elevation angle
You can choose which diffuse model to use. The isotropic diffuse model is considered more conservative (tendency to underestimate the incident radiation on an inclined plane) but is easier to use. The diffuse model Hay Davies Klucher Reindl (HDKR) is preferred in solar applications (photovoltaic, solar thermal ...).
Known limits / Use precautions
none
Validations
Validated model:
- Aurélie Kaemmerlen 02/2011: Validation of similar model developed for BESTEST (time in RST) and DIRH and GLOH input fluxes: verification with TRNSYSv16: TMY reading with Type89i and calculation of incidents fluxes with Type16g Analytical Validation (Via Excel calculations) on the model parametrization: type of weather, type of average and flows considered
- Amy Lindsay 03/2013: validation du modèle de diffus HDKR sur données d'ensoleillement à PV ZEN
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Licensed by EDF under a 3-clause BSD-license
Copyright © EDF 2009 - 2023
BuildSysPro version 3.6.0
Author : Aurélie KAEMMERLEN, EDF (2011)
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Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Units.NonSI.Angle_deg | azimut | Surface azimuth (Orientation relative to the south) - S=0°, E=-90°, W=90°, N=180° | |
| Modelica.Units.NonSI.Angle_deg | incl | Surface tilt - downwards = 180° skyward = 0°, vertical = 90° | |
| Boolean | use_Albedo_in | false | Variable Albedo |
| Real | albedo | 0.2 | Albedo of the environment |
| Integer | diffus_isotrope | 1 | Model for diffuse irradiance |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Blocks.Interfaces.RealInput[10] | G | Inputs data {DIFH, DIRN, DIRH, GLOH, t0, CosDir[1:3], solar azimuth angle, solar elevation angle} | |
| BuildSysPro.BoundaryConditions.Solar.Interfaces.SolarFluxOutput[3] | FluxIncExt | Surface irradiance in [W/m²] 1-Diffuse, 2-Direct and 3-Cosi | |
| Modelica.Blocks.Interfaces.RealOutput[3] | AzHSol | Solar azimuth and elevation angle and diffuse irradiation | |
| Modelica.Blocks.Interfaces.RealInput | Albedo_in | Albedo |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Units.SI.HeatFlux | DIRH | ||
| Modelica.Units.SI.HeatFlux | DIRN | ||
| Modelica.Units.SI.HeatFlux | GLOH | ||
| Modelica.Units.SI.HeatFlux | DIFH | ||
| Modelica.Units.SI.HeatFlux | DiffusSol | Part of the diffuse irradiance from the ground reflection | |
| Real | sin_h | ||
| Real | cosi |
Revisions
Aurélie Kaemmerlen 02/2011 :
- Ajout de la paramétrisation de la moyenne des flux mesurés (Booléen MoyFlux) et du choix des flux en entrée
- Correction dans le calcul du cosi : il manquait le paramètre h0 !
Aurélie Kaemmerlen 05/2011 :
- Ajout de sorties : hauteur et azimut du soleil, Rayonnement incident diffus provenant du sol
- Vecteur Gh de dimension 9 (anciennement 6) pour ajouter les entrées CoupleFlux, MoyFlux et dt
- Ajout d'une sécurité pour éviter un flux direct infini : sin_h>0.01 au lieu de >0 pour le calcul de FDIRN/FDIRH
Hassan Bouia 03/2013 : Simplication du calcul solaire - attention nouvelle dimension du vecteur Gh renommé en G
Amy Lindsay 03/2013 : Ajout du paramètre diffus_isotrope pour choisir entre un modèle de diffus isotrope ou le modèle de diffus HDKR
Aurélie Kaemmerlen 09/2013 : Ajout du choix de mettre un albédo variable (mesures BESTLAB par exemple) et ajout d'un max entre 0 et DIRN pour éviter les valeurs négatives au lever-coucher de soleil