Equations for conductive shape factors are presented. The products of these factors with conductivity give the conductances of a thermal model. Four new equations treat: the truncated hollow cone with variable wall thickness, the truncated full cone, the trapezium and the cube. Since the equation for spherical segments is usually not given in literature it is also presented.
The shape factors found by these equations are compared with results determined by the ’area/distance’ equation, by TMG and/or by equations from literature. The TMG programm with automatic meshing was used with varying node numbers. It is shown that many nodes are needed for most of the chosen examples in order to obtain a convergence to a sufficient precise result. The practical advantage of the presented equations is thus to allow a reduction of the number of nodes for a desired precision of the model.