Heat transfer simulation in encapsulated phase change materials for energy storage application

In the pursuit of sustainable energy systems, the complexity of technological integration is crucial for overcoming future challenges. Encapsulated Phase Change Materials (EPCM) have emerged as prominent players in this field due to their exceptional heat storage capabilities, offering vital and efficient energy management solutions for diverse eco-friendly applications. Despite their appealing characteristics, the large-scale integration of EPCM faces hurdles, particularly concerning the maintenance of structural integrity amid phase transitions characterized by uneven thermal distribution and stress accumulation due to volume changes. These challenges can lead to structural damage, thereby impacting system efficiency, environmental safety, and hindering public acceptance and utilization of EPCM technologies [1][2]. Recent studies have explored the behaviour of Encapsulated Phase Change Materials (EPCM) through simulations. However, many of these studies still rely on simplified unrealistic assumptions, such as maintaining constant volume during phase changes, thereby neglecting the complex stress scenarios encountered in practical applications [3]. This study establishes a comprehensive model to simulate the conjugate heat transfer process in EPCM, encapsulating it within a solid sphere and exposing it to a turbulent environment. The heat transfer coefficients between different interfaces throughout the heat transfer process were investigated using computational fluid dynamics (CFD) simulations. In addition, the analysis focused on the uneven temperature distribution, which was verified to be mainly caused by changes in the contact medium within the encapsulation material and boundary layer separation on the outer surface.