Microencapsulated phase change materials for enhanced thermal energy storage performance in construction materials: A critical review

Abstract

The potential of phase change materials (PCM) as a thermal energy storage medium in buildings has been widely discussed. However, the possible leakage of melted PCM into construction material matrix could have deleterious effects on some of the intrinsic properties of these materials. To prevent this, PCM is microencapsulated in micron size shells to form microencapsulated phase change materials (MPCM). Numerous studies in the literature, including reviews, have shown that MPCM can enhance the thermal performance of construction materials and reduce operational carbon emissions associated with frequent heating and cooling of buildings. However, there is limited information on the effects of the shell material encapsulating the PCM on the thermal performance of PCM as well as its effect on the inherent properties of cementitious composites and gypsum boards. This information is extremely useful for better understanding of how the known properties of construction material will be affected by the incorporation of MPCM into its matrix. In this study, we critically analyzed how MPCM affects the fresh and hardened properties of construction materials. More also, general overview of PCM, microcapsules, production process of MPCM, and various thermal enhancement methods for MPCM were also rigorously discussed and evaluated. The findings from this study show that biobased PCM can be an environmentally friendly alternative replacement for paraffins and MPCM can improve thermal performance of construction materials. The low-cost advantage of inorganic PCM over organic PCM makes it a potential candidate for economical thermal energy storage solutions. Furthermore, MPCM typically lowers the mechanical properties of building materials, with a considerable loss reported in MPCM with organic shells as opposed to inorganic microcapsules. The workability of cementitious composite decreases with increasing MPCM content, and the shell material and morphology are significant contributing factors. The highlighted knowledge gaps for future research to support MPCM scalability and large-scale applications were critically reviewed. The findings from this review provide invaluable insights for researchers, engineers, and key stakeholders in the construction industry on the recent developments and huge potential of MPCM for building thermal management.