Experimental Investigations on the Thermal Performance and Phase Change Hysteresis of Low-Temperature Paraffin/MWCNTs/SDBS Nanocomposite via Dynamic DSC Method

Abstract

Phase change materials (PCMs) with ideal thermal property, has become a critical hallmark in thermal energy storage (TES). The phase change hysteresis (PCH) phenomenon is particularly prominent since the phase transition of PCM mixture non-isothermal. In this paper, a paraffin-based nanocomposite PCM were prepared, the multiwalled carbon nanotubes (MWCNTs) and sodium dodecyl benzene sulfonate (SDBS) were comprised for the enhancement of thermal conductivity and suspension stability. The PA/MWCNTs/SDBS composite PCM exhibited excellent chemical compatibility, better thermal storage capacity, high thermal charging and discharging efficiency, and preferable thermal and cyclic stability through a series of characterization. Furthermore, the differential scanning calorimetry (DSC) was performed to investigate the association of temperature range, temperature changing rate, and sample mass on hysteresis degree. Besides, the causes of PCH were interpretated from the respective of energy storage, temperature delay, thermal resistance of PCMs, crystallinity, and interfacial free energy. The results showed that PCH phenomenon is controllable, thereby improving the energy utilization efficiency of PCMs. Namely, the prepared PA/MWCNTs/SDBS composite PCM with suitable phase transition temperature of 5.5 °C, high latent heat of 222.7 J g -1 , and thermal conductivity of 0.3727 W m -1 K -1 , possesses enormous potential in large-scale applications.