modelSimpleHouse3

Air model

Extends from SimpleHouse2 (Building window model).

Information

To increase the model detail we now add an air model assuming the zone is 8m x 8m x 3m in size. The air will exchange heat with the wall. This may be modelled using a thermal resistance representing the convective heat resistance which is equal to Rconv=1/(h*A), where A is the heat exchange surface area and h=2 W/(m2*K) is the convective heat transfer coefficient.

Required models

Connection instructions

The MixingVolume Medium parameter contains information about the type of fluid and its properties that should be modelled by the MixingVolume. Set its value to MediumAir, which is declared in the template, by typing redeclare package Medium = MediumAir. For the nominal mass flow rate you may assume a value of 1 kg/s for now. You will have to change this value once you add a ventilation system to the model (see Buildings.Examples.Tutorial.SimpleHouse.SimpleHouse6). Finally, set the energyDynamics of the MixingVolume, which can be found in the Dynamics tab of the model parameter window, to FixedInitial.

Make a connection with the PrescribedHeatFlow as well. This block makes the connection between the heat flow from the gain, represented as a real value, and a heat port that is compatible with the connectors of the thermal capacitance and resistance.

Reference result

The result with and without the air model is plotted in the figure below.

Wall temperature as function of time, with (green) and without (blue) air model.

Parameters

TypeNameDefaultDescription
Modelica.Units.SI.AreaAWall (from SimpleHouse0)100Wall area
Modelica.Units.SI.LengthdWall (from SimpleHouse0)0.25Wall thickness
Modelica.Units.SI.ThermalConductivitykWall (from SimpleHouse0)0.04Wall thermal conductivity
Modelica.Units.SI.DensityrhoWall (from SimpleHouse0)2000Wall density
Modelica.Units.SI.SpecificHeatCapacitycpWall (from SimpleHouse0)1000Wall specific heat capacity
Modelica.Units.SI.AreaAWin (from SimpleHouse2)2Window area
Modelica.Units.SI.VolumeVZone8*8*3Zone volume
Modelica.Units.SI.MassFlowRatemAir_flow_nominal1Nominal mass flow rate for air loop
Modelica.Units.SI.CoefficientOfHeatTransferhWall2Convective heat transfer coefficient at the wall

Connectors

TypeNameDefaultDescription
Buildings.BoundaryConditions.WeatherData.BusweaBus (from SimpleHouse0)Weather data bus

Components

TypeNameDefaultDescription
Buildings.BoundaryConditions.WeatherData.ReaderTMY3weaDat (from SimpleHouse0)Weather data reader
Buildings.HeatTransfer.Sources.PrescribedTemperatureTOut (from SimpleHouse0)Exterior temperature boundary condition
Modelica.Thermal.HeatTransfer.Components.HeatCapacitorwalCap (from SimpleHouse1)Thermal mass of wall
Modelica.Thermal.HeatTransfer.Components.ThermalResistorwalRes (from SimpleHouse1)Thermal resistor for wall: 25 cm of rockwool
Modelica.Blocks.Math.GaingaiWin (from SimpleHouse2)Gain for solar irradiance through the window
Modelica.Thermal.HeatTransfer.Sources.PrescribedHeatFlowwin (from SimpleHouse2)Very simple window model
Modelica.Thermal.HeatTransfer.Components.ThermalResistorconResThermal resistance for convective heat transfer
Buildings.Fluid.MixingVolumes.MixingVolumezonVery simple zone air model

Revisions

  • September 4, 2023, by Jelger Jansen:
    First implementation.