Thermal performance of a ventilated window integrated with PCM-filled tubes across seasons

Conventional phase change material (PCM)-filled double-glazing windows are constrained by limited dynamic thermal regulation capability and inferior climate adaptability, severely limiting their practical engineering applications. This study proposes a novel double-glazed ventilated window incorporating PCM-filled glass tubes (TPVW) and establishes a transient non-grey numerical model that accounts for the spectral selectivity of the glass panes. Two-stage validation against published experimental data verifies that the developed non-grey model exhibits higher prediction accuracy than conventional grey models. The thermal performance of TPVW is comprehensively investigated under typical summer and winter conditions in Guilin, China. Comparative analyses with air-filled windows (DW), PCM-filled windows (PDW), and TPCM-filled windows (TPDW) are conducted to reveal the synergistic mechanism between PCM-filled glass tube (TPCM) and ventilation. Furthermore, the effects of TPCM diameter and arrangement are explored, and the coupling relationship between air flow characteristics and heat transfer behavior is clarified. The results demonstrate that TPVW achieves excellent thermal performance in summer and winter, and the combined application of TPCM and mechanical ventilation significantly enhances the latent heat regulation capability of the glazing system. In summer, TPCM with smaller diameters effectively improve the thermal regulation capability of TPVW, whereas the cross arrangement of TPCM increases solar heat gain. Under the current conditions, the TPVW with 8 mm parallel-arranged TPCM (TPVW-2PA) reduces energy loss by 44.8% in summer and 31.9% in winter, and achieving a dynamic payback period from 13.1 to 17.8 years. Notably, the TPVW equipped with 4 mm parallel-arranged TPCMs (TPVW-4PA) delivers a superior summer energy-saving rate of 52.9%. Full-year assessment, prototype experiment, daylighting evaluation and durability testing remain necessary before engineering application.