Enabling high-strength cement-based materials for thermal energy storage via fly-ash cenosphere encapsulated phase change materials

Abstract The incorporation of phase change materials (PCMs) in cement-based materials opens pathways for large-scale thermal energy storage with tremendous opportunities for energy saving. However, traditional use of polymer micro-encapsulated PCMs (MEPCM) in cement-based materials lead to several well-known drawbacks (e.g., detrimental to mechanical performance, lower thermal conductivity, and high costs). In this research, a novel micro-encapsulation pathway is pursued, using fly-ash cenosphere to encapsulate PCMs for high volume use in cement-based materials. A comparative study was conducted to elucidate the effects of the cenosphere encapsulated PCMs (namely CenoPCM) and its polymer micro-encapsulated counterparts on the mechanical and thermal properties of functionalized cement-based materials. In addition, a micro-mechanics-based model was developed to predict properties of cementitious materials containing MEPCM. Property trade-off analysis shows that CenoPCM has substantial potential in the development of heat-storing cement-based materials, due to its significantly improved mechanical properties, good thermal conductivity, and much lower cost than other MEPCMs.