modelInfraredRadiationExchange

Infrared radiation heat exchange between the room facing surfaces

Extends from Buildings.ThermalZones.Detailed.BaseClasses.PartialSurfaceInterfaceRadiative (Partial model that is used for infrared radiation balance).

Information

This model computes the infrared radiative heat transfer between the interior surfaces of a room. Each opaque surface emits radiation according to

Eⁱ = σ Aⁱ εⁱ (Tⁱ)⁴,

where σ is the Stefan-Boltzmann constant, Aⁱ is the surface area, εⁱ is the absorptivity in the infrared spectrum, and Tⁱ is the surface temperature. If the parameter linearizeRadidation is set to true, then the term (Tⁱ)⁴ is replaced with T₀³ Tⁱ, where T₀ = 20°C is a parameter.

The incoming radiation at surface i is

Gⁱ = -∑_j F^j,i J^j

where F^j,i is the view factor from surface j to surface i, J^j is the radiosity leaving surface j and the sum is over all surfaces. For opaque surfaces, it follows from the first law that the radiosity Jⁱ is

Jⁱ = -Eⁱ - (1-εⁱ) Gⁱ.

For windows, the outgoing radiosity is an input into this model because the window model computes this quantity directly.

For each surface i, the heat balance is

0 = Qⁱ + Jⁱ + Gⁱ.

For opaque surfaces, the heat flow rate Qⁱ is set to be equal to the heat flow rate at the heat port. For the glass of the windows, the radiosity outflow at the connector is set to the radiosity Gⁱ that is leaving the surface.

The view factor from surface i to j is approximated as

F^i,j = A^j ⁄ ∑_k A^k.

Parameters

Type	Name	Default	Description
Integer	NConExt (from ConstructionNumbers)	max(1, nConExt)	Number of elements for exterior constructions
Integer	NConExtWin (from ConstructionNumbers)	max(1, nConExtWin)	Number of elements for exterior constructions with windows
Integer	NConPar (from ConstructionNumbers)	max(1, nConPar)	Number of elements for partition constructions
Integer	NConBou (from ConstructionNumbers)	max(1, nConBou)	Number of elements for constructions that have their outside surface exposed to the boundary of this room
Integer	NSurBou (from ConstructionNumbers)	max(1, nSurBou)	Number of elements for surface heat transfer models that connect to constructions that are modeled outside of this room
Boolean	haveConExt (from ConstructionNumbers)	nConExt > 0	Flag to conditionally remove components
Boolean	haveConExtWin (from ConstructionNumbers)	nConExtWin > 0	Flag to conditionally remove components
Boolean	haveConPar (from ConstructionNumbers)	nConPar > 0	Flag to conditionally remove components
Boolean	haveConBou (from ConstructionNumbers)	nConBou > 0	Flag to conditionally remove components
Boolean	haveSurBou (from ConstructionNumbers)	nSurBou > 0	Flag to conditionally remove components
ParameterConstruction[NConExt]	datConExt (from ConstructionRecords)		Data for exterior construction
Buildings.ThermalZones.Detailed.BaseClasses.ParameterConstructionWithWindow[NConExtWin]	datConExtWin (from ConstructionRecords)		Data for exterior construction with window
Buildings.ThermalZones.Detailed.BaseClasses.ParameterConstruction[NConPar]	datConPar (from ConstructionRecords)		Data for partition construction
Buildings.ThermalZones.Detailed.BaseClasses.ParameterConstruction[NConBou]	datConBou (from ConstructionRecords)		Data for construction boundary
Buildings.ThermalZones.Detailed.BaseClasses.OpaqueSurface[NSurBou]	surBou (from ConstructionRecords)		Record for data of surfaces whose heat conduction is modeled outside of this room
HeatTransfer.Data.OpaqueConstructions.Brick120	dummyCon (from ConstructionRecords)		Dummy construction to assign a parameter to the instance
Buildings.HeatTransfer.Data.GlazingSystems.SingleClear3	dummyGlaSys (from ConstructionRecords)		Dummy construction to assign a parameter to the instance
Boolean	homotopyInitialization	true	= true, use homotopy method
Boolean	linearizeRadiation		Set to true to linearize emissive power
Exterior constructions
Integer	nConExt (from ConstructionNumbers)		Number of exterior constructions
Integer	nConExtWin (from ConstructionNumbers)		Number of window constructions
Partition constructions
Integer	nConPar (from ConstructionNumbers)		Number of partition constructions
Boundary constructions
Integer	nConBou (from ConstructionNumbers)		Number of constructions that have their outside surface exposed to the boundary of this room
Integer	nSurBou (from ConstructionNumbers)		Number of surface heat transfer models that connect to constructions that are modeled outside of this room
Experimental (may be changed in future releases)
Boolean	sampleModel	false	Set to true to time-sample the model, which can give shorter simulation time if there is already time sampling in the system model

Connectors

Type	Name	Description
Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_a[NConExt]	conExt (from PartialSurfaceInterface)	Heat port that connects to room-side surface of exterior constructions
Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_a[NConExtWin]	conExtWin (from PartialSurfaceInterface)	Heat port that connects to room-side surface of exterior constructions that contain a window
Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_a[NConExtWin]	conExtWinFra (from PartialSurfaceInterface)	Heat port that connects to room-side surface of window frame
Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_a[NConPar]	conPar_a (from PartialSurfaceInterface)	Heat port that connects to room-side surface a of partition constructions
Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_a[NConPar]	conPar_b (from PartialSurfaceInterface)	Heat port that connects to room-side surface b of partition constructions
Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_a[NConBou]	conBou (from PartialSurfaceInterface)	Heat port that connects to room-side surface of constructions that expose their other surface to the outside
Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_a[NSurBou]	conSurBou (from PartialSurfaceInterface)	Heat port to surfaces of models that compute the heat conduction outside of this room
HeatTransfer.Interfaces.RadiosityInflow[NConExtWin]	JInConExtWin	Incoming radiosity that connects to non-frame part of the window
HeatTransfer.Interfaces.RadiosityOutflow[NConExtWin]	JOutConExtWin	Outgoing radiosity that connects to non-frame part of the window

Revisions

November 30, 2021, by Michael Wetter:
Removed test on radiation balance that was added for debugging purposes.
April 14, 2020, by Michael Wetter:
Changed homotopyInitialization to a constant.
This is for IBPSA, #1341.
January 23, 2017, by Michael Wetter:
Corrected wrong start value for J. The start value was positive, but J(each max =0).
This is for issue 627.
May 21, 2015, by Michael Wetter:
Reformulated to reduce use of the division macro in Dymola. This is for issue 417.
May 30, 2014, by Michael Wetter:
Removed undesirable annotation Evaluate=true.
June 27, 2013, by Michael Wetter:
Changed model because the outflowing radiosity has been changed to be a non-negative quantity. See track issue #158.
April 18, 2013, by Michael Wetter:
Removed cardinality function as this is deprecated in the MSL specification and not correctly implemented in omc.
February 10, 2012 by Wangda Zuo:
Fixed a bug for linearization of T4.
April 21, 2011 by Michael Wetter:
Fixed a bug in the view factor calculation, and rewrote the model to reduce simulation time. The bug caused too much radiosity to flow from large to small surfaces because the law of reciprocity for view factors was not satisfied. This led to low surface temperatures if a surface had a large area compared to other surfaces.
April 2, 2011 by Michael Wetter:
Added homotopy operator.
Feb. 3, 2011, by Michael Wetter:
Corrected bug in start value of radiosity, reformulated equations to get smaller system of coupled equations.
Dec. 1, 2010, by Michael Wetter:
First implementation.