Buildings.HeatTransfer.Data.BaseClasses

Information

Package Content

Name	Description
Material	Thermal properties of materials w/o storage

Buildings.HeatTransfer.Data.BaseClasses.Material

Information

The specific heat capacity can be zero, in which case the material will be modeled as a thermal resistor that does not store energy.

Note that the thermal resistance is in units of m2*K/W and not K/W because this record does not have the surface area as a parameter. The surface area will be defined in the model of the construction that uses this material. This allows use of the same material in walls, floors and ceilings of different surface area.

Extends from Modelica.Icons.Record (Icon for a record).

Parameters

Type	Name	Default	Description
Length	x		Material thickness [m]
ThermalConductivity	k		Thermal conductivity [W/(m.K)]
SpecificHeatCapacity	c		Specific heat capacity [J/(kg.K)]
Density	d		Mass density [kg/m3]
Real	R		Thermal resistance of a unit area of material [m2.K/W]
Integer	nStaRef	3	Number of state variables in a reference material of 0.2 m concrete
Boolean	steadyState	(c == 0 or d == 0)	Flag, if true, then material is computed using steady-state heat conduction
Advanced
Integer	nSta	max(1, integer(ceil(nStaReal...	Actual number of state variables in material
Real	piRef	331.4	Ratio x/sqrt(alpha) for reference material of 0.2 m concrete
Real	piMat	if steadyState then piRef el...	Ratio x/sqrt(alpha)
Real	nStaReal	nStaRef*piMat/piRef	Number of states as a real number

Modelica definition

record Material "Thermal properties of materials w/o storage"
  extends Modelica.Icons.Record;
  parameter Modelica.SIunits.Length x "Material thickness";
  parameter Modelica.SIunits.ThermalConductivity k "Thermal conductivity";
  parameter Modelica.SIunits.SpecificHeatCapacity c "Specific heat capacity";
  parameter Modelica.SIunits.Density d "Mass density";
  parameter Real R(unit="m2.K/W") 
    "Thermal resistance of a unit area of material";
  parameter Integer nStaRef(min=0) = 3 
    "Number of state variables in a reference material of 0.2 m concrete";
  parameter Integer nSta(min=1)=max(1, integer(ceil(nStaReal))) 
    "Actual number of state variables in material";
  parameter Boolean steadyState= (c == 0 or d == 0) 
    "Flag, if true, then material is computed using steady-state heat conduction";
  parameter Real piRef=331.4 
    "Ratio x/sqrt(alpha) for reference material of 0.2 m concrete";
  parameter Real piMat=if steadyState then piRef else x*sqrt(c*d)/sqrt(k) 
    "Ratio x/sqrt(alpha)";
  parameter Real nStaReal(min=0) = nStaRef*piMat/piRef 
    "Number of states as a real number";

end Material;