Phase change materials in latent thermal energy storage systems: experimental and numerical investigations

This PhD Thesis investigates Phase Change Materials (PCMs) with a focus on their behavior during melting and solidification, particularly for applications in Latent Thermal Energy Storage (LTES) systems and electronic component protection during reflow soldering. The study begins by contrasting Sensible and Latent Thermal Energy Storage systems, highlighting PCMs' higher energy storage density. Strategies to enhance PCMs’ low thermal conductivity, such as the use of metal foams, fins, and carbon-based additives, are also discussed. An experimental analysis of a prototype LTES system utilizing a paraffinic PCM and a finned-tube heat exchanger was conducted. The system’s thermal performance during charging and discharging phases was evaluated and compared to that of a conventional STES system using water, demonstrating the superior efficiency of LTES in terms of energy storage and thermal power exchange. Further numerical investigations examined PCM melting and solidification within heated/cooled cavities, evaluating the effects of metallic fin configurations. Two case studies were conducted: one on melting in a rectangular cavity with and without vertical fins, and another on phase transitions within a double cavity system. Results demonstrated that fin placement significantly influences heat transfer dynamics and efficiency. The final part of the research explores an industrial application, assessing PCMs’ capability to protect sensitive electronic components during Surface Mount Device (SMD) soldering. Numerical simulations and experimental validations confirmed that integrating PCMs reduces thermal stress, improving component reliability. Overall, this Thesis provides a comprehensive analysis of PCMs in both theoretical and practical contexts, contributing new insights into optimizing thermal management systems and proposing innovative solutions for industrial heat control. Future research directions aim to further enhance PCM-based systems for broader and more efficient energy applications.