Thermal performance evaluation of encapsulation materials for organic PCM-based cool thermal energy storage systems

The present study explores the intrinsic techniques of encapsulation materials and the storage performance of PCM for the optimal utilization of cool thermal energy storage systems to meet cooling load demands. Three encapsulation materials—stainless steel (SS), copper (Cu), and low-density polyethylene (LDPE)—were examined based on thermal conductivity and phase change characteristics. The optimal encapsulation material was identified using differential scanning calorimetry (DSC 214-Polyma). Results indicate that Cu and SS exhibited earlier melting onset temperatures (-5°C and -3.5°C, respectively), while LDPE delayed melting onset (0.5°C) and provided a larger melting range, ensuring controlled phase change. Furthermore, the phase change and thermal response of an organic mixture (OM05) PCM were analyzed through temperature-time (T-t) profiles during charging and discharging experimentation. Heat flow variations (5 K/min) influenced phase change temperatures and enthalpy values, with first derivative DSC analysis refining thermal transition points. OM05 exhibited reliable thermal cycling stability, with significant drop in latent heat from 242 J/g to 236 J/g. Thermal resistance (0.133 K/mK) and peak specific heat capacity (41.351 J/g.K) were identified. Overall, these findings highlight the critical role of choosing optimal encapsulation materials, focusing on their durability, energy storage capacity, and phase change dynamics for effective utilization in cool thermal energy storage (CTES) systems.