Modeling and analysis of a dual-channel solar thermal storage wall system with phase change material in hot summer and cold winter area

A dual-channel solar thermal storage wall system with eutectic phase change material is studied. The full-day cooling load in summer and heating load in winter can be both decreased by this novel system. To investigate the airflow in the dual channel, mixed area assumptions based on the experimental results are summarized. Dynamic mathematical models of the system under four work modes are established and verified by the experimental results. The average RMSD (root mean square deviation) value is 0.35% in summer and 0.95% in winter. By analyzing the heat flux, the combination of dual channel and PCM is proven to decrease and delay cooling load both in the daytime and nighttime of summer. In winter's daytime, the thermal efficiency is promoted by the dual channel. And in winter's nighttime, the system is able to heat the room constantly by the PCM boards. Based on parameter researches, the optimum phase change temperature range and the optimum thickness of the PCM are 26–30 ℃, 1.5 cm in summer and 16–22 ℃, 0.6 cm in winter respectively. To reach the optimum annual thermal performance, the coverage area is 2 m² for this system.