Innovative PCM-enhanced recycled concrete for year-round energy savings and thermal regulation in buildings

Reducing reliance on energy-inefficient mechanical cooling systems by improving building energy efficiency is critical for transforming the global energy landscape and achieving sustainability. This study introduces a novel phase change material–impregnated recycled concrete aggregate (RCA–PCM) composite concrete designed to deliver year-round energy savings and enhanced thermal regulation. The RCA–PCM concrete achieves a compressive strength of 48.7 MPa–47.1 % higher than standard RCA concrete, while providing effective latent heat storage of ∼9.2 J/g, enabling superior thermal and energy performance. Prototype testing demonstrates that this innovative material can lower peak indoor temperatures by up to 7.2 °C compared to RCA concrete and 5 °C compared to conventional concrete during summer conditions. EnergyPlus simulations indicate that incorporating RCA–PCM concrete into building walls and roofs can reduce energy consumption by 37.1 %, corresponding to an annual CO₂ emission reduction of 2.12 billion metric tons, or 5.7 % of global emissions. Manufactured using abundant recycled concrete waste and simple technologies, this sustainable material offers a scalable and practical solution for minimizing the construction industry's carbon footprint while advancing global carbon neutrality goals.