Heat transfer through building envelopes significantly contributes to overall energy consumption. Owing to the property of having steady melting/freezing heat storage in a narrow temperature range, phase change materials (PCMs) provide a promising solution to improve building envelope energy management.
With the design objective of channeling the force of natural resources, a solar- adaptive, PCM-integrated window system is proposed that can store and utilize “free” heat from solar radiation. The fully charged PCM panels will transfer the stored thermal energy to the cool air by conduction and warm the air. Therefore, the system is designed to passively reduce total energy consumption and improve indoor thermal comfort.
Parametric studies were conducted to maximize the thermal performance of a PCM-contained panel by varying the inlet air velocity, the melting temperature of PCMs, and the shape, allocation, and size of individual PCM cells. The output of the parametric study identified the optimal PCM panel design and was used as the input of the next stage computational fluid dynamics (CFD) simulations. To further evaluate and validate the effectiveness of the proposed system, as well as to visualize the airflow of the passively heated air, indoor CFD simulations were also performed. There were two scenarios: the first was to study the efficiency of heating cool indoor air near the facade, and the second was to investigate the performance of the system to heat the cold outdoor air.