Comprehensive performance evaluation of double-glazed windows containing hybrid nanoparticle-enhanced phase change material

Abstract

Utilizing hybrid nanoparticle-enhanced phase change material (Nano-PCM) in double-glazed windows can improve the thermal inertia and thermal insulation of windows, but the excessive photothermal conversion capacity causes the window to overheat locally in summer and affects thermal comfort. Moreover, the addition of hybrid nanoparticles also affects the visible light transmittance of liquid PCM, which negatively impacts natural lighting. Therefore, a comprehensive evaluation of the glazed window filled with hybrid Nano-PCM is required. In this study, Al2O3-CuO hybrid Nano-PCMs were first prepared to measure and calculate their optical properties in the full spectral band. The evaluation system of the glazed window containing hybrid Nano-PCM was established from the multi-perspectives of energy-saving, thermal comfort, economy, and daylighting. A numerical simulation model was developed to study the optical and thermal performance of glazed units. The results show that the addition of hybrid Nano-PCM has a positive effect on the energy and economic saving. This positive effect is more profound as the proportion of CuO increases under the range of 0.001 % volume fraction, which can save 2552 kJ/d energy and 2003 CNY in the life cycle of the studied window. The thermal comfort index and natural lighting index increase with the increase of the Al2O3 ratio under the range of 0.001 % volume fraction. The maximum average indoor natural lighting reaches 361.89 lx, and the maximum temperature deviation is 9.31℃. In terms of energy consumption, energy-saving, daylighting, and economic factors, the best comprehensive performance for the window is achieved at CuO: Al2O3 ratio of 4:6.