modelSkymodelBase
Extends from ExtraTerrestrialIrradiance (Calculates the extraterrestrial irradiance of the sun), TransiEnt.Basics.Icons.Model (Icon for models).
Information
1. Purpose of model
Base model for modeling the influence of orientation of a surface for calculation of irradiance.
2. Level of detail, physical effects considered, and physical insight
ratio_beam is invalid for small angles
3. Limits of validity
Usage for small values of angleOfSunIncidence.horizontal is not recommended because of refraction by atmosphere
4. Interfaces
(no remarks)
5. Nomenclature
direct_tilted, diffuse_tilted and ground_tilted are the calculated irradiances of tilted surface.
6. Governing Equations
7. Remarks for Usage
Model needs outer variables SI.Irradiance direct_measured, diffuse_horizontal, sun_horizontal.
8. Validation
purely theoretical model
9. References
Duffie/Beckman (2006): Solar Engineering of Thermal Processes
10. Version History
Model created by Tobias Toerber (tobias.toerber@tuhh.de), Jul 2015
Edited by Sascha Guddusch (sascha.guddusch@tuhh.de), May 2016
Modified by Anne Senkel (anne.senkel@tuhh.de), Mar 2017
Modified by Lisa Andresen (andresen@tuhh.de), Apr. 2017
Model modified by Oliver Schülting (oliver.schuelting@tuhh.de), May 2018
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Real | offset (from SolarTime) | {0, 0, 0, 0} | |
| SI.Angle | longitude_local (from SolarTime) | Modelica.Units.Conversions.from_deg(10) | East positive, west negative, 10 for Hamburg |
| SI.Angle | longitude_standard (from SolarTime) | Modelica.Units.Conversions.from_deg(15) | 15 needed for offset calculation of central european time, 30 for central european summer time |
| Real | utc (from SolarTime) | longitude_standard*12/Const.pi | Difference between UTC and zone time; i.e. +1 in Amsterdam/Berlin/Bern/Rome; default works for standard time, beware of summer time ! |
| SI.Irradiance | solarConstant (from ExtraTerrestrialIrradiance) | 1367 | |
| SI.Angle | latitude (from ExtraTerrestrialIrradiance) | Modelica.Units.Conversions.from_deg(53.55) | latitude of the position, north posiive, 53,55 N for Hamburg |
| SI.Angle | slope (from ExtraTerrestrialIrradiance) | Modelica.Units.Conversions.from_deg(30) | slope of the tilted surface, Assumption |
| SI.Angle | surfaceAzimuthAngle (from ExtraTerrestrialIrradiance) | 0 | Angle between the local meridian and the projection of the normal of the surface on a horizontal surface, west positive |
| Boolean | fixedMounting (from ExtraTerrestrialIrradiance) | true | choose if surface is fix mounted - if 'true' the sun position is ideally tracked |
| Real | reflectance_ground | 0.2 | Reflection coefficient of the ground |
| Boolean | direct_normal | true | =true, if the direct irradiance measured on a surface is normal to irradiance |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Units.NonSI.Time_day | dayoftheyear (from SolarTime) | Day as floating point number. 0.0 at 1.1. 00:00:00, 1.0 at 2.1. 00:00:00 a.s.o. | |
| Modelica.Units.NonSI.Time_day | totaldays (from SolarTime) | 365 | total days of the year, standard=365, leap year=366 |
| SI.Time | solarTime (from SolarTime) | Local solar time in seconds | |
| SI.Time | offset_sec (from SolarTime) | ||
| SI.Angle | angle_horizontal (from ExtraTerrestrialIrradiance) | ||
| SI.Angle | angle_tilted (from ExtraTerrestrialIrradiance) | ||
| SI.Irradiance | irradiance_extraterrestrial (from ExtraTerrestrialIrradiance) | ||
| SI.Angle | declination (from ExtraTerrestrialIrradiance) | ||
| SI.Angle | hourAngle (from ExtraTerrestrialIrradiance) | ||
| SI.Irradiance | irradiance_direct_measured | Measured direct irradiance | |
| SI.Irradiance | irradiance_diffuse_horizontal | Measured diffuse irradiance | |
| SI.Irradiance | irradiance_direct_horizontal | Direct horizontal irradiance | |
| SI.Irradiance | irradiance_direct_tilted | ||
| SI.Irradiance | irradiance_diffuse_tilted | ||
| SI.Irradiance | irradiance_ground_tilted | ||
| Real | ratio_beam | Ratio between direct irradiance on a tilted surface and irradiance on a horizontal surface |