modelOneElement

Thermal Zone with one element for exterior walls
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Extends from Buildings.Fluid.Interfaces.LumpedVolumeDeclarations (Declarations for lumped volumes).

Information

This model merges all thermal masses into one element, parameterized by the length of the RC-chain nExt, the vector of the capacities CExt[nExt] that is connected via the vector of resistances RExt[nExt] and RExtRem to the ambient and indoor air. By default, the model neglects all internal thermal masses that are not directly connected to the ambient. However, the thermal capacity of the room air can be increased by using the parameter mSenFac.

The image below shows the RC-network of this model.

image

Parameters

TypeNameDefaultDescription
Booleanuse_moisture_balancefalseIf true, input connector QLat_flow is enabled and room air computes moisture balance
Dynamics › Conservation equations
Modelica.Fluid.Types.DynamicsenergyDynamics (from LumpedVolumeDeclarations)Modelica.Fluid.Types.Dynamics.DynamicFreeInitialType of energy balance: dynamic (3 initialization options) or steady state
Modelica.Fluid.Types.DynamicssubstanceDynamics (from LumpedVolumeDeclarations)energyDynamicsType of independent mass fraction balance: dynamic (3 initialization options) or steady state
Modelica.Fluid.Types.DynamicstraceDynamics (from LumpedVolumeDeclarations)energyDynamicsType of trace substance balance: dynamic (3 initialization options) or steady state
Advanced › Dynamics
Modelica.Fluid.Types.DynamicsmassDynamics (from LumpedVolumeDeclarations)energyDynamicsType of mass balance: dynamic (3 initialization options) or steady state, must be steady state if energyDynamics is steady state
Initialization
Medium.AbsolutePressurep_start (from LumpedVolumeDeclarations)Medium.p_defaultStart value of pressure
Medium.TemperatureT_start (from LumpedVolumeDeclarations)Medium.T_defaultStart value of temperature
Medium.MassFraction[Medium.nX]X_start (from LumpedVolumeDeclarations)Medium.X_defaultStart value of mass fractions m_i/m
Medium.ExtraProperty[Medium.nC]C_start (from LumpedVolumeDeclarations)fill(0, Medium.nC)Start value of trace substances
Medium.ExtraProperty[Medium.nC]C_nominal (from LumpedVolumeDeclarations)fill(1E-2, Medium.nC)Nominal value of trace substances. (Set to typical order of magnitude.)
Dynamics
RealmSenFac (from LumpedVolumeDeclarations)1Factor for scaling the sensible thermal mass of the volume
Thermal zone
Modelica.Units.SI.VolumeVAirAir volume of the zone
Modelica.Units.SI.CoefficientOfHeatTransferhRadCoefficient of heat transfer for linearized radiation exchange between walls
IntegernOrientationsNumber of orientations
General › Ports
IntegernPorts0Number of fluid ports
Windows
Modelica.Units.SI.Area[nOrientations]AWinVector of areas of windows by orientations
Modelica.Units.SI.Area[nOrientations]ATransparentVector of areas of transparent (solar radiation transmittend) elements by orientations
Modelica.Units.SI.CoefficientOfHeatTransferhConWinConvective coefficient of heat transfer of windows (indoor)
Modelica.Units.SI.ThermalResistanceRWinResistor for windows
Modelica.Units.SI.TransmissionCoefficientgWinTotal energy transmittance of windows
RealratioWinConRadRatio for windows between indoor convective and radiative heat emission
BooleanindoorPortWinfalseAdditional heat port at indoor surface of windows
Exterior walls
Modelica.Units.SI.Area[nOrientations]AExtVector of areas of exterior walls by orientations
Modelica.Units.SI.CoefficientOfHeatTransferhConExtConvective coefficient of heat transfer of exterior walls (indoor)
IntegernExtNumber of RC-elements of exterior walls
Modelica.Units.SI.ThermalResistance[nExt]RExtVector of resistances of exterior walls, from inside to outside
Modelica.Units.SI.ThermalResistanceRExtRemResistance of remaining resistor RExtRem between capacity n and outside
Modelica.Units.SI.HeatCapacity[nExt]CExtVector of heat capacities of exterior walls, from inside to outside
BooleanindoorPortExtWallsfalseAdditional heat port at indoor surface of exterior walls
Advanced
Booleanuse_C_flowfalseSet to true to enable input connector for trace substance

Connectors

TypeNameDefaultDescription
Modelica.Blocks.Interfaces.RealInput[nOrientations]solRadSolar radiation transmitted through windows
Modelica.Blocks.Interfaces.RealInputQLat_flowLatent heat gains for the room
Modelica.Blocks.Interfaces.RealOutputTAirIndoor air temperature
Modelica.Blocks.Interfaces.RealOutputTRadMean indoor radiation temperature
Modelica.Fluid.Vessels.BaseClasses.VesselFluidPorts_b[nPorts]portsAuxiliary fluid inlets and outlets to indoor air volume
Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_aextWallAmbient port for exterior walls
Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_awindowAmbient port for windows
Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_aintGainsConvAuxiliary port for sensible internal convective gains
Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_aintGainsRadAuxiliary port for internal radiative gains
Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_awindowIndoorSurfaceAuxiliary port at indoor surface of windows
Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_aextWallIndoorSurfaceAuxiliary port at indoor surface of exterior walls
Modelica.Blocks.Interfaces.RealInputC_flowTrace substance mass flow rate added to the thermal zone

Components

TypeNameDefaultDescription
Fluid.MixingVolumes.MixingVolumevolAirIndoor air volume
Fluid.MixingVolumes.MixingVolumeMoistAirvolMoiAirIndoor air volume
Modelica.Thermal.HeatTransfer.Components.ThermalResistorresWinResistor for windows
Modelica.Thermal.HeatTransfer.Sources.PrescribedHeatFlowconvHeatSolSolar heat considered as convection
Modelica.Thermal.HeatTransfer.Sources.PrescribedHeatFlow[nOrientations]radHeatSolSolar heat considered as radiation
BaseClasses.ThermSplitterthermSplitterIntGainsSplits incoming internal gains into separate gains for each wall element, weighted by their area
BaseClasses.ThermSplitterthermSplitterSolRadSplits incoming solar radiation into separate gains for each wall element, weighted by their area
BaseClasses.ExteriorWallextWallRCRC-element for exterior walls

Revisions

  • March 7, 2022, by Michael Wetter:
    Removed massDynamics.
    This is for #1542.
  • October 9, 2019, by Michael Wetter:
    Refactored addition of moisture to also account for the energy content of the water vapor.
    This is for IBPSA, issue 1209.
  • September 24, 2019, by Martin Kremer:
    Added possibility to consider moisture balance.
    Defined volAir conditional. Added conditional volMoistAir and corresponding in- and output connectors.
  • July 11, 2019, by Katharina Brinkmann:
    Renamed alphaRad to hRad, alphaWin to hConWin, alphaExt to hConExt, alphaExtWallConst to hConExtWall_const, alphaWinConst to hConWin_const
  • January 25, 2019, by Michael Wetter:
    Added start value to avoid warning in JModelica.
  • September 26, 2016, by Moritz Lauster:
    Added conditional statements to solar radiation part.
    Deleted conditional statements of splitFactor and splitFactorSolRad.
  • April 17, 2015, by Moritz Lauster:
    First implementation.