A novel heat pipe based thermal analysis technique is modelled. The technique is able to monitor and control the casting quality of aluminium alloys during solidification. The two-dimensional model, based on the control volume finite difference approach and on the enthalpy method, uses cylindrical coordinates to simulate the solidification behaviour of an aluminium button located inside the heat pipe probe. The model is able to identify the critical parameters affecting the operation of the system. These are the melt temperature, the location of the control thermocouple in the sample, the temperature of the working substance in the heat pipe and the cooling air flowrate. A good agreement between predicted and measured thermal values is obtained for the 319 and 356 aluminium alloys used to test the technique.