Innovative PCM-integrated calcium silicate panels for thermal regulation in building envelopes

• Calcium silicate boards host up to 72% by weight of Phase Change Material • PCM-impregnated panels show losses of less than 1%, ensuring leak-proof performance • Impregnation preserves the thermal storage capacity of PCM • PCM-impregnated panel effectively mitigate temperature fluctuation • Analyses show that the system is suitable for thermal buffering in buildings Buildings significantly contribute to global energy consumption and CO 2 emissions, underscoring the need for energy-efficient building solutions that enhance thermal comfort. Existing Phase Change Materials (PCMs)-based thermal storage solutions are promising but often suffer from leakage or loss of latent heat capacity. This study addresses these limitations by developing ready to use, leak-proof composite panels through direct impregnation of porous calcium silicate boards with organic PCMs for efficient latent heat storage in buildings. Two paraffinic PCMs were incorporated into two calcium silicate panels with different microstructure using the direct impregnation technique. The resulting composites boards were characterised by leakage tests, Fourier Transformed Infrared Spectroscopy, Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis, Scanning Electron Microscopy, thermal conductivity measurements, and controlled thermal response experiments. The panels achieved high PCM uptake exceeding 69 wt.% with negligible leakage (