Micro-scale thermal analysis of energy storage in cement-based composites containing phase change materials (PCMS)

Abstract

In the last decades, the use of smart components embedded inside cementitious materials, like Phase Change Material (PCM), has become a more and more attractive solution for saving energy and for providing a more efficient thermal comfortability to modern buildings. Present research running at the Institute of Construction and Building Materials (WiB) of TU-Darmstadt deals with the investigation of advanced coupling of two physical mechanisms represented by a heat problem and microstructural heterogeneities. The thermal response of such a composite system, along with occurring phase change phenomena, will be simulated at the microscale level. A virtual 3D porous microstructure with embedded PCMs, created with the available hydration model Hymostruc, provides a fundamental basis for the analysis of the morphological influence of PCMs on the effective thermal diffusion parameters. The work is aimed at investigating the influence of the morphological effect on the thermal effective properties of hydrating cement combined with Micro-encapsulated (M)-PCMs. Laboratory characterization of the PCMs was performed using a designated test set-up. The thermal performance of cement-based pastes with and without MPCMs were experimentally evaluated and used as benchmark for calibration purposes. Particularly, the obtained results combined with specific heat capacity of PCM-cement pastes and thermal conductivity measurements were taken as reference for validating the proposed numerical technique.