Photothermal performance investigation of a reversible window combining paraffin and silica aerogel

The development of smart glazed envelopes is essential to achieve zero-carbon buildings. This paper proposed a novel reversible triple-glazed window integrated with paraffin and silica aerogel to address season change, and numerically investigates its photothermal performance in summer and winter of southwest China based on a developed CFD model. Firstly, the thermal behaviors of five window configurations are compared regarding thermal comfort and energy efficiency to clarify the optimal arrangement and the interaction mechanism between paraffin and aerogel in two seasons. Then, the influences of the phase change temperature of paraffin and the thickness ratio of paraffin to aerogel are analyzed across seasons. Furthermore, the optical properties of the novel window are calculated through Double-thickness Method, which with different paraffin-aerogel thickness ratios are quantitatively compared. Finally, the daylighting performance of a residence incorporated with the novel window is examined using Ecotect software under different PCM phase states. The results show that the reversible window is promised to achieve year-round high efficiency and thermal comfort, while providing an eligible nature light environment. Under the studied climate conditions, the case with 28°Cparaffin and 9:9 paraffin-aerogel ratio is recommended, saving energy consumption by 26 % in summer and 27 % in winter.