Numerical Energy Performance Analyses of New Heat Storage Batteries by Using Thermal Enhanced Grouts and PCM
Authors: Isania Fatemeh , Franze Sara , Martelletto Francesca , Dallasanta Giorgia , Scotton Paolo , Doretti Luca , Galgaro Antonio 
Published: March 2024

In addressing imbalances between energy supply and demand within thermal systems, the incorporation of latent heat thermal energy storage alongside sensible heat thermal energy storage emerges as a reliable and efficient solution. This synergistic approach optimizes system performance by integrating phase change materials (PCMs) for enhanced thermal management. This paper introduces a pioneering strategy by incorporating a novel coaxial borehole heat exchanger-PCM system to augment thermal system efficiency. The study employs an innovative numerical framework that integrates Multiphysics coupling, encompassing heat transfer, double fluid flow, and phase change phenomena within a complex geometry. A comprehensive three-dimensional computational fluid dynamics simulation is conducted for an exhaustive numerical heat transfer analysis. The investigation delves into the dynamic behavior of the system during both PCM charging and discharging processes, providing an in-depth assessment of its thermal performance. By exploring the intricate interactions of heat transfer, fluid flow, and phase change within a complex geometry, the research contributes valuable insights into advancing the understanding of complex thermal systems through innovative numerical methodologies. Furthermore, to optimize the overall performance of the system, an observation is made regarding the marginal decrease in the released heat load with an increased fluid flow rate. This phenomenon results in a substantial reduction in heating time, demonstrating the potential impact of fluid flow manipulation on system efficiency. The thermal energy storage system presented in this research serves as a groundbreaking solution, specifically designed to address the intermittent nature inherent in generating electricity for the grid from renewable resources. The enhancement of heat exchange processes related to increasing the thermal conductivity and capacity of the storage mass and heat exchanger, and a special solution to insulate the heat storage volume not only improve the heat exchanging rate but also aids the reduction of heat dissipation, playing a crucial role in significantly maximize the system efficiency. This innovative technology stands as a pioneering remedy, promoting effective energy utilization and strengthening the thermal management capabilities of heating and cooling systems. Moreover, it contributes to the advancement of sustainable practices by facilitating electricity generation from renewable sources. In conclusion, this comprehensive study not only introduces a novel coaxial borehole heat exchanger-PCM system but also provides a detailed analysis of its dynamic behavior through advanced numerical simulations. The findings offer valuable insights into the optimization of thermal systems, emphasizing the potential benefits of incorporating both latent and sensible heat thermal energy storage with innovative fluid flow strategies for enhanced efficiency in renewable energy applications.