Optimization of an innovative delignified wood-structured phase change roof integrated with sky radiation cooling

This research develops a delignified wood-based phase-change composite roof system synergized with sky radiative cooling (DIPCM-SRC), designed to mitigate building energy consumption and operational carbon footprint. Parameter optimization was performed, and the energy-saving and carbon-reduction performance was evaluated across different climate zones. Systematic single-factor and orthogonal experimental optimization of roof parameters yielded an optimal phase change material (PCM) melting temperature of 24.0 °C (20 °C–28 °C), with a 30 mm (10 mm–100 mm) DIPCM layer and 40 mm (10 mm–100 mm) insulation layer. Subsequent COMSOL simulations demonstrated that the optimized DIPCM-SRC roof reduced exterior and interior surface heat fluxes by 42.3 % and 51.3 %, respectively, compared to references wooden roof of identical construction, while extending indoor thermal comfort duration by 2.2-fold. Full-scale EnergyPlus modeling of the experimental setup quantified an average cooling energy savings rate of 17.4 % with associated carbon emission reductions averaging 3.2 %, reaching 7.7 % when excluding severe cold regions. The optimized DIPCM-SRC roof effectively integrates PCM thermal storage technology and sky radiative cooling technology, thereby contributing to energy savings and carbon emission reduction in buildings during summer operational conditions.