Comparative Analysis of Thermal Energy Management for Different Phase Change Materials by Polypyrrole Impregnation

Abstract

Energy storage systems have emerged as a key area of research due to growing global energy sustainability concerns. Phase change materials (PCMs) store energy in the form of latent heat and have applications at various temperatures. In the present work, Octadecane (M.P. 28°C) and Paraffin wax (M.P. 58°C) are selected as phase change materials, while Polypyrrole is chosen as a supporting material. Octadecane or Paraffin-based composites with varying weight percentages of Polypyrrole are prepared by the direct melt mixing method. Leakage tests suggest that Octadecane having 30 wt% Polypyrrole (OCT/PPY-3 composite) and Paraffin having 20 wt% of Polypyrrole (PAR/PPY-2 composite) show excellent shape stability. XRD patterns and FTIR spectra confirm the successful synthesis of OCT/PPY-3 and PAR/PPY-2 composites without any impurities or chemical reactions. DSC analysis reveals that Polypyrrole impregnation decreases the latent heat of octadecane and paraffin by 88 and 68 J g⁻¹, respectively, without any change in the melting temperature of the respective PCMs. Polypyrrole impregnation enhances the thermal stability and thermal conductivity of octadecane by 30°C and 47%, respectively; however, it does not affect paraffin. Charging and discharging times of pure PCM are shortened by polypyrrole impregnation. Therefore, the inherent properties of OCT and paraffin have been altered in distinct ways as a result of polypyrrole impregnation. In conclusion, OCT/PPY-3 can be considered a promising material for thermal management in buildings and textiles, while PAR/PPY-2 can be a promising candidate for water heaters and solar cookers.