Tuning the Crystallization Properties of Advanced Phase Change Materials




Bithi, Swastika
Aria, Saman
Larson, William

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Petroleum-based paraffin waxes are versatile phase change materials (PCMs) with attractive benefits such as high latent heat, chemical inertness, low vapor pressure, and good thermal stability. Nevertheless, a significant drawback of paraffin waxes is low thermal conductivity, making heat storage and release slow. Nanomaterials with high thermal conductivity can be used as dopants in paraffin waxes. However, the PCMs must undergo many heating and cooling cycles (>1000) in a PCM-based energy storage system. The stability and dispersion characteristic of nanomaterials after several thermal cycles also change the phase transition properties of PCMs. Due to the repetitive thermal cycle, little fundamental understanding exists of phase change behavior. We propose to exploit the effect of thermal cycles on the phase transition behavior of carbon nanotube (CNT) doped commercial paraffin. In this study, we take two approaches: 1) a bulk phase measurement of the phase change behavior mechanism (dispersion of nanomaterial, heat of fusion, crystallinity, and weight loss) using SEM-EDS, DSC, XRD, and TGA, respectively, and 2) parallel a phase contrast microscopy methods to directly visualize the stochastic nature of the onset of crystallization and melting of microcapsules of CNT-doped paraffin.


Phase change materials have been used in various applications, including thermal storage of building materials and electronic cooling systems, industrial waste heat recovery[1-3], and heat exchangers for spacecraft [4] because of their high latent heat. PCMs are projected to have a $3.1 billion market by 2026[5]. Thus, the advanced PCMs developed in this study are expected to have a significant economic impact. PCMs are preferred in heat exchangers because of their greater heat storage density than traditional liquids' sensible heat limitations. Among the PCMs, paraffin waxes have gained attention due to their higher latent heat of fusion, low vapor pressure, inert nature, and thermal stability[3]. However, the main difficulty for paraffin waxes is their low thermal conductivity


2024 Faculty and Student Research Poster Session and Research Fair, West Texas A&M University, College of Engineering, Poster, Nanomaterials, Phase change materials