Layered laser-engraved wood-based composite capable of photothermal conversion and energy storage for indoor thermal management in buildings

Wood is used more and more in building. Phase change materials (PCM) with automatic temperature regulation and heat storage function have been widely concerned in the field of building energy conservation. However, phase-change materials have poor light induction and cannot absorb sunlight during the day in time, resulting in limited heat storage effect. For the purpose of achieving efficient energy collection and utilization, a laser-engraved method was employed in this study to directly generate a three-dimensional grid structure on the surface of wood. Then, the eutectic mixture of capric acid (CA) and stearic acid (SA) and nano-SiO2 composite PCM (CPCM) was impregnated into the supporting substrate with photothermal conversion capability. The obtained laser-engraved wood (LEW) loaded with CA-SA/Nano-SiO2 showed a latent heat of 64.706 J/g, a thermal conductivity of 0.732 W/(m⋅K) and a photothermal conversion efficiency of 64.46 %. Additionally, the three-dimensional porous structure of wood and the addition of nano-silica set up a double barrier for the leakage of PCM. Therefore, CPCM have prospective applications as indoor thermal insulation materials. In this research, a simple laser engraving method was adopted to endow the wooden substrate with photothermal conversion ability, which provides an idea to expand the application of photothermal conversion materials in the field of phase-change energy storage. In addition, the building simulation software validated the potential of CPCM in stabilizing indoor temperatures and reducing building energy consumption.