Study on multi-band spectral regulation performance of single-layer thermochromic coatings based on VO₂ core-shell particles for building energy conservation

The spectral regulation performance of smart windows significantly impacts building energy consumption. Compared to thermochromic coatings that modulate only the sunlight band, those capable of multi-band modulation-including both sunlight and mid-to-far infrared bands-have the potential to further reduce energy consumption in buildings. The thermochromic coating based on multi-layer structures with multi-band modulation ability reported so far is unsuitable for practical application due to its complex preparation process and high cost. This study proposed a single-layer smart window coating utilizing core@VO₂ particles to achieve multi-band modulation. This single-layer coating offers the advantages of simple preparation and convenient construction. We investigated the influence of parameters such as the shell-to-core ratio, particle volume fraction, and refractive index of the substrate on the spectral radiative properties using the FDTD method. Additionally, the impacts of variations in these parameters on energy consumption and carbon dioxide emissions were analyzed using EnergyPlus. The simulation results indicated that the core@VO₂ nanoparticle coating possessed a maximum solar modulation ability of 27.6%, luminous transmittance of 48.15%, and maximum emissivity modulation ability of 16.7%. Compared with traditional low-e coatings, the maximum energy-saving efficiency increased by 7.36%. This study provides valuable insights for enhancing the energy efficiency of thermochromic smart window coatings.