Spectrally selective nanoparticle-enhanced phase change materials: A study on data-driven optical/thermal properties and application of energy-saving glazing under different climatic conditions

The optical and thermal performances of energy-saving glazing require improvement to reduce peak thermal load and increase solar energy conversion and management efficiency. Herein, it is indispensable to develop novel composite materials that designate the ability to achieve multifunction by thermal load migration as well as radiation transmittance modulation. This study developed a nanoparticle-enhanced phase change material (NEPCM) with spectrally selective and phase change functions. A data-driven algorithm is first developed to evaluate the solar-weighted absorption fraction, integrated irradiance, and spectral irradiance for the considered nanoparticles. The base fluids, nanoparticle diameter, concentrations, and proportions are taken into account in the program, and adjustments to the properties of NEPCM can be easily made. The NEPCM properties exhibit a high blocking performance of near-infrared solar radiation by 30.9%, while keeping visible transmittance at 51.8% using ATO-Al2O3 NEPCM. Furthermore, the photothermal conversion performance of a NEPCM-filled energy-saving prototype window is explored, which yields a heat absorption rate of up to 0.27 °C/min when the solar irradiance is 800 W/m2. In addition, the energy consumption of transparent envelopes with NEPCM filler in a full-scale building is investigated. The results show that NEPCM regulated glazing potentially provides annual heating energy-saving from 5.1 to 41.7 kWh·m−2·year−1 in three representative climatic conditions in different global locations. Outcomes on the spectrally selective capabilities of the energy-saving window provide ideas for advancing the development of low-carbon transparent building envelopes.