Enhancing Building Energy Efficiency: Leaf Transpiration Inspired Construction of Lignin-Based Wood Plastic Composites for Building Energy Conservation

Abstract

Incorporating phase change materials (PCMs) into buildings represents a strategic method for reducing reliance on air conditioning systems and decreasing energy usage consequently. Inspired by leaf veins providing channels for transpiration, lignin porous carbon (LPC) was synthesized by chemical activation, showing a vein pore structure. The capillary network system of the LPC provided more channel to adsorb PCM through surface tension and capillary force, achieving an impressive loading capacity of LPC for polyethylene glycol (PEG) (75%), which demonstrated exceptional heat storage capability (133.21 J/g). The lignin-derived wood-plastic composite (L-WPC) was further prepared. With the gradual increase of LPC/PEG, the latent heat of L-WPC increased gradually. The ΔHm, ΔHc and energy storage efficiency of L-WPC-50 (incorporated 50 wt% LPC/PEG-75) reached 39.99 J/g, 42.65 J/g and 90.26%, respectively. The vein pore structure of LPC also provided a thermal conductivity link for L-WPC. L-WPC-50 demonstrated an increased thermal conductivity (0.66 W/(m·K)) and a reduced thermal diffusion coefficient (0.24 mm2/s), optimizing the effectiveness of the phase transition. Additionally, L-WPC-50 displayed satisfactory mechanical properties and dimensional stability, with tensile strength, bending modulus and water absorption thickness swelling rate measuring 14.40 MPa, 1043.72 MPa, and 1.61% respectively. It introduced a feasible approach for utilizing biomass in enhancing building energy efficiency, marking a significant stride towards reducing building energy consumption and advocating sustainable energy practices.