Abstract:
A new type of multistage phase-change solar ventilation ceiling(MPCSVC)based on solar hot air heating system is investigated in this paper. Numerical model of MPCSVC was established,and the heat charging and discharging characteristics of singlestage,two-stage and three-stage phase change solar ventilation ceiling were compared. The effects of the proportions of phase change material(PCM)and air velocity on the heat storage and release performance were analyzed. The results show that compared with the ventilation ceiling with single PCM,the average outlet temperature difference of that with MPCSVC is smaller in the heat storage and release process. In addition,the heat charging and discharging efficiency and the utilization rate of PCM for the three-stage MPCSVC are improved up to 6.5%,7.9% and 25.1%,respectively. The optimal length ratio of PCM in MPCSVC is 1∶1∶1,and the heat charging and discharing efficiency and the utilization rate of PCM are 51.0%,88.7% and 93.9%,respectively. The air velocity should not be larger than 1.6 m/s,and the air velocity can be appropriately reduced under the premise of ensuring the heating effect.