Paper presented at the 6th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 30 June - 2 July, 2008.
An apparatus was developed to measure the thermal diffusivity of solids with particular emphasis on building materials which do not necessarily have smooth surfaces. Time dependent temperature variations, which may be general, on the cold and hot surfaces of a specimen are used as boundary conditions for a numerical solution of the governing heat flow equation. A least average absolute temperature difference between measured and calculated mid-point temperatures is used to obtain the thermal diffusivity. The apparatus provides a base for the development of improved methods of measuring the thermal properties of materials.