Form-stable microencapsulated phase change materials for efficient solar thermal energy storage

• A promising microfluidic encapsulation technique is proposed. • A novel phase change heat storage microcapsule was developed. • Microencapsulated phase change materials for storage/release of thermal energy such as solar energy. Phase change materials (PCMs), renowned for their exceptional heat storage capabilities, have been extensively utilized in solar energy utilization. However, the persistent challenge of liquid leakage during their use remains unresolved. In this study, a promising microfluidic encapsulation technology is presented, leading to the development of a novel phase change heat storage microcapsule. Differential scanning calorimetry measurements confirm the retention of over 88% of the latent heat of the phase change material (up to 171.8 J/g). Additionally, CFD modeling demonstrates that the geometric structure of the microcapsules significantly enhances heat transfer, effectively addressing the issue of low heat transfer efficiency in PCM systems. Leakage tests have demonstrated the exceptional cyclic stability of microcapsule encapsulation, as it exhibits no leakage even after undergoing 100 consecutive melting-freezing cycles. Moreover, it experiences only a minimal 4.2% loss in latent heat. The incorporation of microcapsule encapsulation into phase change heat storage technology opens up exciting opportunities for harnessing the full potential of phase change materials .