Structural design and performance evaluation of a high-transparency thermal insulation film suitable for multiple scenarios

Abstract

With the continuous rise in global temperatures, the demand for indoor cooling has increased significantly. Among all enclosure structures, transparent glass serves as the primary pathway for heat transfer. Glass with high-transparency thermal insulation (HTTI) film exhibits tremendous potential for significantly reducing cooling energy consumption due to its excellent spectral selectivity. An ideal transparent structure should reflect as much near-infrared radiation as possible while maintaining high visible light transmittance. However, conventional solutions face certain limitations. For example, some transparent structural film containing metallic layers cannot provide sufficiently high transmittance, while others such as polymer-based film absorb solar energy and generate heat, making it difficult to balance energy efficiency and optical performance. In this study, a high-precision multilayer film structure was designed based on a Fabry–Pérot (FP) cavity configuration, using pure dielectric SiO₂/TiO₂ as the periodic units. A neural network was employed to optimize the multilayer film structure. The resulting design achieves a theoretical visible light transmittance (T_VIS) exceeding 90% and a theoretical near-infrared reflectance (R_NIR) over 90%. Experimental results show that, compared to conventional transparent glass, this HTTI film can reduce indoor temperatures by up to 10 °C and save as much as 130 MJ m⁻² of energy annually. This HTTI film structure demonstrates remarkable energy-saving potential and application prospects in fields such as architecture, transportation, and wearable electronics, making it particularly suitable for green and low-carbon development in hot climates.