modelExteriorBoundaryConditions
Information
This model computes the boundary conditions for the outside-facing surface of opaque constructions.
The model computes the infrared, solar, and convective heat exchange between these surfaces and the exterior temperature and the sky temperature. Input into this model are weather data that may be obtained from Buildings.BoundaryConditions.WeatherData.
In this model, the solar radiation data are converted from horizontal irradiation to irradiation on tilted surfaces using models from the package Buildings.BoundaryConditions.SolarIrradiation. The convective heat transfer between the exterior surface of the opaque constructions is computed using Buildings.HeatTransfer.Convection.
The heat transfer of windows are not computed in this model. They are implemented in Buildings.ThermalZones.Detailed.BaseClasses.ExteriorBoundaryConditionsWithWindow.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Boolean | linearizeRadiation | Set to true to linearize emissive power | |
| ParameterConstruction[nCon] | conPar | ||
| Exterior constructions | |||
| Integer | nCon | Number of exterior constructions | |
| Convective heat transfer | |||
| Buildings.HeatTransfer.Types.ExteriorConvection | conMod | Buildings.HeatTransfer.Types.ExteriorConvection.TemperatureWind | Convective heat transfer model for opaque part of the constructions |
| Modelica.Units.SI.CoefficientOfHeatTransfer | hFixed | 10.0 | Constant convection coefficient for opaque part of the constructions |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_a[nCon] | opa_a | Heat port at surface a of opaque construction | |
| BoundaryConditions.WeatherData.Bus | weaBus |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| HeatTransfer.Convection.Exterior[nCon] | conOpa | Convection model for opaque part of the wall | |
| SkyRadiationExchange | skyRadExc | Infrared radiative heat exchange with sky | |
| BoundaryConditions.SolarIrradiation.DirectTiltedSurface[nCon] | HDirTil | Direct solar irradiation on the surface | |
| BoundaryConditions.SolarIrradiation.DiffusePerez[nCon] | HDifTil | Diffuse solar irradiation | |
| Modelica.Blocks.Math.Add[nCon] | HTotConExt | Total solar irradiation | |
| Buildings.HeatTransfer.Sources.PrescribedHeatFlow[nCon] | solHeaGaiConExt | Total solar heat gain of the surface |
Revisions
-
September 24, 2025, by Jianjun Hu:
Explicitly assigned value to the roughness of the exterior constructions.
This is for issue 4367. -
September 16, 2021, by Michael Wetter:
Removed parameterlatbecause the latitude is now obtained from the weather data bus.
This is for IBPSA, #1477. -
August 9, 2011 by Michael Wetter:
Changed assignment of tilt in instanceconOpa. This fixes the bug in issue 35 that led to the wrong solar radiation gain for roofs and floors. (Since the tilt has been changed in the model Buildings.ThermalZones.Detailed.MixedAir at the place where it makes an instance of this model, the change in the tilt parameter of the convective heat transfer model was required.) -
March 28, 2011, by Michael Wetter:
Propaged parameterhFixedto top-level of the model. -
March 23, 2011, by Michael Wetter:
Removed default value for convection model. -
November 23, 2010, by Michael Wetter:
First implementation.