This is a model for transport of heat without storing it; see also: ThermalResistor. It may be used for complicated geometries where the thermal conductance G (= inverse of thermal resistance) is determined by measurements and is assumed to be constant over the range of operations. If the component consists mainly of one type of material and a regular geometry, it may be calculated, e.g., with one of the following equations:
Conductance for a box geometry under the assumption that heat flows along the box length:
    G = k*A/L
    k: Thermal conductivity (material constant)
    A: Area of box
    L: Length of box
    
    Conductance for a cylindrical geometry under the assumption that heat flows from the inside to the outside radius of the cylinder:
    G = 2*pi*k*L/log(r_out/r_in)
    pi   : Modelica.Constants.pi
    k    : Thermal conductivity (material constant)
    L    : Length of cylinder
    log  : Modelica.Math.log;
    r_out: Outer radius of cylinder
    r_in : Inner radius of cylinder
    
    
    Typical values for k at 20 degC in W/(m.K):
      aluminium   220
      concrete      1
      copper      384
      iron         74
      silver      407
      steel        45 .. 15 (V2A)
      wood         0.1 ... 0.2