Enable solar regulation and thermal insulation improvement of transparent wood with oriented VO2-Cellulose fiber

Abstract

Compared to commercial glass, transparent wood-based windows is provided with better thermal insulation performance, and more comparable solar transmittance. However, transparent wood cannot dynamically regulate solar light switching between summer and winter, and its insulation is worth improving but without a clear micron thermal mechanism model. Herein, a thermochromic and insulation transparent window composed of oriented cellulose attached by VO2 nanoparticles was prepared, and its thermal conductivity model of micron cellulose, VO2 nanoparticles, and PMMA polymer was established. The results show that the extinction coefficient of Cell-wall@VO2@PMMA is improved to 21.68 % when the VO2 occurs phase change at near-infrared spectra. The optimal angle of cellulose for comprehensive insulation performance of blocking near-infrared and heat conduction equals 60°. Besides, the transparent wood sample demonstrates a low thermal conductivity of Cell-wall@VO2@PMMA, reaching to 0.175 W·m−1·K−1, as well as reducing the temperature difference by 36.8 %. This paper provides a novelty heat transfer perspective for designing thermochromic transparent cellulose with excellent insulation performance in the future.