Thermal performance of an innovative double-skin ventilated facade with multistep-encapsulated PCM integration

The simultaneous occurrence of nighttime insulation requirements and daytime overheating risks in a single day is a concern of buildings that is often overlooked. This study introduces a novel approach utilizing a dual-phase change materials (DPCM) layer in a double-skin ventilated glazing facade (DSPVGF) to store and release energy through photothermal conversion. This technology facilitates heat removal during the day via a ventilation layer and the reduces long-wave radiation through a vacuum glass layer. The thermal performance of DSPVGF is evaluated under a temperate continental climate characterized by significant diurnal temperature variations. Emphasis is placed on considering the net solar energy gain of DSPVGF. The results demonstrate that DSPVGF outperforms ventilated facades utilizing air or PCM, exhibiting the lowest heat transfer rate of 30.03 W. Optimal DSPVGF configurations for climates with substantial temperature fluctuations are identified, including a DPCM melting temperature of 28 degrees C and 16 degrees C, a thickness of 36 mm, and multistep placement by turn according to a height-to-width ratio of 200D. Daytime ventilation with a flow velocity of 1.09 m.s(-1) is confirmed as the most effective passive cooling strategy.