HeatScopy - Visualizing the Structure of Phase Change Materials

ongoing

Seasonal and short-term heat storage with phase change materials (PCMs) represent a promising alternative to traditional carbon-intensive energy systems. They could reduce greenhouse emissions and provide sustainable renewable heating systems. Paraffin waxes have demonstrated potential for this purpose and fillers to enhance the thermal conductivity of waxes have been developed. However, these mixtures are expensive and unsustainable to upscale. Bio-based PCMs are cheaper, but often come with large heterogeneities, for which heat storage performance is difficult to predict. This study proposes the advancement of experimental methodologies to identify the impact of heterogeneities and mixture composition on phase change material performance for the development of sustainable products. An experimental approach is particularly beneficial, since computational techniques often require assumptions for high purity, which deviate significantly from the composition of naturally-occuring waxes. In this context, the proposed project will build on new experimental tools enabling to characterize heterogeneous and more complex mixtures, shed light on literature gaps about the mechanism of co-crystallization and speed up the selection of more sustainable and less costly PCMs. This study proposes to use atomic force microscopy, low field nuclear magnetic resonance, inverse gas chromatography and T-history, to reveal the mechanism behind the structural evolution during the phase change. A workflow will be developed using conventional paraffin wax and filler mixtures. Then, the established workflow will be applied to plant-based waxes, such as soy wax and coconut oil-based wax. The final goal is to predict heat storage performance of novel materials, from the evolution of structural features characterized experimentally. This workflow will facilitate the selection and testing for PCM to ensure optimal heat storage performance and a reduction in greenhouse emissions for heating.