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