Through a combination of theoretical and experimental research, this paper aims at evaluating the suitability of a transient plane heat source (TPS) method for the visualisation of the activity of phase change materials (PCMs). The TPS method provides measurements of thermal conductivity and thermal diffusivity of a material in a transient course. It has previously been tested on various building materials but not on PCMs. In this study TPS was tested in a laboratory environment on two inorganic PCMs (salt-hydrates), with melting temperatures 21 oC and 24 oC respectively. Based on the experimental trials, the technique has shown to be a valuable technique for the identification of the activity of phase change material
