modelExteriorHeatRadiation
longwave radiative heat exchange of an exterior surface with the environment
Information
Longwave radiation Q̇lw between the surface and the environment is determined according to the Stefan-Boltzmann law as
Q̇lw = σ · εlw · A · (Ts4 - Fsky · Tsky4 - (1 - Fsky) · Tdb4)
where
- σ is the Stefan-Boltzmann constant [Mohr 2008],
- εlw is the longwave emissivity of the exterior surface A,
- Fsky is the radiant-interchange configuration factor between the surface and sky [Hamilton 1952], and the surface and the environment, respectively, and
- Ts and Tsky are the exterior surface and sky temperature, respectively.
Shortwave solar irradiation absorbed by the exterior surface Q̇sw is determined as
Q̇sw = εsw · A · Esw
where
- εsw is the shortwave absorption of the surface A, and
- Esw the total irradiation on the depicted surface.
References
[Hamilton 1952]: D.C. Hamilton, and W.R. Morgan,
"Radiant-interchange configuration factors",
Technical Report – National Advisory Committee for Aeronautics, Washington, 1952.
[Mohr 2008]: P.J. Mohr, B.N. Taylor, and D.B. Newell,
"CODATA recommended values of the fundamental physical constants: 2006",
Review of Modern Physics, vol. 80, pp. 633–730, 2008.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Units.SI.Area | A | Surface area of heat exchange surface | |
| Boolean | linearise | true | If true, linearise radiative heat transfer |
| Modelica.Units.SI.Emissivity | epsLw | Long wave emissivity | |
| Linearisation | |||
| Modelica.Units.SI.Temperature | Tenv_nom | 280 | Nominal temperature of environment |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_a | port_a | ||
| Modelica.Blocks.Interfaces.RealInput | Tenv | Radiative temperature of the environment |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Thermal.HeatTransfer.Sources.PrescribedTemperature | preTem | Prescribed temperature block | |
| IDEAS.Buildings.Components.BaseClasses.RadiativeHeatTransfer.HeatRadiation | heaRad | Component for computing radiative heat |
Revisions
-
June 17, 2025, by Lucas Verleyen:
Replaced images with inline equations. See #1440.