Energy-efficient foam concrete with phase change composites: Field-scale thermoregulation tests

The integration of phase change materials (PCMs) into lightweight foam concrete presents a promising approach for improving the energy efficiency of buildings, as it couples thermal insulation with effective thermal energy storage capacity. In this research, expanded perlite (EP) was impregnated with capric acid (CA) to produce EP/CA composites, which were incorporated into foam concrete mixtures at various substitution levels. The resulting composites retained up to 58 % CA without leakage and exhibited a phase transition enthalpy of 96.4 J/g with a melting point of 29.2 ˚C. Increasing EP/CA content reduced flow diameter and dry density, while leading to higher porosity and water absorption. Both mechanical strength and thermal conductivity declined with higher EP/CA ratios, with 30 % replacement mixture showing the lowest values (4.04 MPa and 0.213 W/m·K, respectively). Field-scale evaluations of thermal comfort performance revealed that the mixture containing 30 % EP/CA reduced peak indoor temperatures by approximately 6.6 ˚C during daytime and provided a modest nighttime heating benefit of up to 1.1 ˚C. Overall, these results demonstrate the strong potential of EP/CA modified foam concrete to moderate indoor thermal fluctuations and contribute to improved building energy efficiency. • EP, is porous and lightweight, was preferred as the support material. • Innovative and lightweight foam concrete with solar thermoregulatory ability. • The presence of EP/CA composite improved thermal insulation performance of foam concrete. • Solar thermoregulation tests were performed under real weather conditions in a specially designed room.