Theoretical investigation of VO2 smart window with large-scale dynamic infrared emittance adjustment for adaptive thermal management

Abstract

Thermochromic windows based on vanadium dioxide (VO₂) are widely used in architectural windows due to its reversible phase change process. However, traditional VO₂ windows only manage solar radiative transmittance and their emittance variation trend in the mid-infrared contradicts realistic requirements, which seriously hinders the further development of thermochromic windows. To address this issue, a VO₂ full-spectrum smart window based on theoretical calculations is proposed for adaptive adjustment of solar spectral transmittance and thermal emittance. We cleverly utilize a thin Ag layer to construct a Fabry-Perot (FP) resonant cavity with the VO₂ layer to achieve forward modulation of the emittance in the atmospheric window. Notably, the smart window has 83.8 % emittance modulated ability, which enables effective control of radiative cooling and has greatly exceeded the reported performance of the smart windows while maintaining 72.8 % high visible transparency. Energy consumption analysis indicates that the smart window has high energy-saving potential worldwide, achieving over 60 MJ/m² energy-saving effect. This simple and easy-to-manufacture smart window expands the research scope of windows and broadens application prospects in thermal management, infrared camouflage, and building energy conservation.