Meso-Scale Thermal Energy Storage Simulations of Cementitious Composites Made with Recycled Brick Aggregates Containing PCM

Abstract

The use of concrete as construction and building material has enormously increased in the last decades. Innovations in the concrete industry are asking for answers in terms of reusing construction demolishing waste, energy saving concepts and cost-effective solutions for CO2 reductions. Therefore, the concrete industry has committed itself towards developing novel technologies for new materials, which are aimed at reducing its carbon footprint dramatically. One promising solution can be achieved by turning cement-based elements into active energy storing systems via the integration of Phase Change Materials (PCMs), to be accommodated in a concrete’s open porosity. In this regard, this work deals with investigating the advanced coupling of two physical mechanisms represented by the thermal energy storage problem and the effect of mesoscale heterogeneities, where the latter is explicitly taken into account. The thermal response of Cementitious Composites made with Recycled Brick Aggregates (RBAs) containing PCM, along with the occurring phase transformation phenomena will be simulated at the meso-scale level. Particularly, 3D mesostructures considering coarse aggregates with embedded PCMs will provide a fundamental basis for the analysis of the morphological influence on the effective thermal energy storage capacity of such composites. The basic equations, employed for predicting phase transformation phenomena in PCM-based systems, and the corresponding simulations demonstrate the capability of the proposed modelling approach. Laboratory characterization of PCM-RBA-mortars were also performed using several test methods and are used as a benchmark for calibration purposes. The research activities presented are developed within the framework of the “2CENERGY” (A Coupled multiscale approach for modelling ENERGY storage phenomena in Cementitious systems) project founded by the Alexander von Humboldt-Foundation (http://www.avh.de).