Bio-based wood-fatty alcohol phase change composite reinforced with hydroxylated carbon nanotubes for thermal energy storage

A bio-based phase change composite was developed by impregnating balsa wood with a eutectic fatty alcohol phase change material (PCM) composed of 1-dodecanol and 1-octadecanol derived from renewable oil-based resources. Before impregnation, the PCM was reinforced with hydroxylated multi-walled carbon nanotubes using salicylic acid as a stabilizing agent to improve thermal conductivity. After impregnation, the composite surface was sealed with a polyurethane layer to prevent PCM leakage. The resulting composite achieved a 62.3 % weight gain, a latent heat of 69.7 J/g, and a peak specific heat capacity of 11.68 J/(g·K) near 20.8 °C, which is about ten times higher than that of conventional structural materials. Infrared imaging revealed a temperature buffering effect of approximately 5 °C, confirming efficient heat regulation. The material maintained excellent structural stability and latent heat retention after 200 thermal cycles. Impregnation tests on five additional wood species showed that pore structure governed PCM uptake and nanofiller dispersion. WUFI simulation predicted a 1.3 °C reduction in indoor peak temperature and a 6 h thermal lag under July climatic conditions in Québec City. This study demonstrates a scalable and sustainable approach to fabricating wood-fatty alcohol phase change composite, providing an efficient bio-based material for building thermal energy storage. Bio-based fatty alcohol PCM in wood with thin PU sealing enables passive thermal buffering (ΔT ≈ 5 °C). • Hydroxylated MWCNTs were stably dispersed in fatty alcohol PCM using salicylic acid as stabilizer. • Vacuum impregnation of balsa wood achieved high PCM uptake (62.3 %) and latent heat storage (69.7 J/g). • Polyurethane coating (200 μm) provided effective leakage protection and cycling durability. • Wood porosity and pore size critically governed PCM impregnation efficiency across wood species. • WUFI simulations revealed 1.3 °C peak temperature reduction and 6 h thermal lag in Québec climate.