In this work, the authors tested five organic phase change materials for thermophysical properties (density, heat capacity, and thermal conductivity) in order to determine the best path to prediction (BPP) for the thermal diffusivity of organic PCMs in the liquid phase. Separate BPPs were determined for alkanes and unsaturated acids. The identified BPPs were then tested on a variety of materials and the estimated thermal diffusivity was within 15% for all ...