Solar chimneys with a phase change material for buildings: An overview using CFD and global energy balance

Abstract

The solar chimney is one concept explored by building engineers and designers for reducing heat gain and inducing natural cooling in both commercial and residential buildings. In this sense, scientists around the world have developed significant research on solar chimneys since the 1990s. This review presents the studies related to the numerical thermal modeling of both, conventional solar chimneys and solar chimneys with phase change materials (PCM). The article focuses on two research areas: Computational Fluid Dynamics (CFD) and Global Energy Balance (GEB). Based on the literature, the CFD approach has become a powerful tool to investigate several aspects concerning the heat transfer mechanisms in a solar chimney. Additionally, the analysis of the literature showed that few calculation tools based on CFD transient state models of solar chimneys are available because the computational time required to solve these models could be excessive and impractical. Therefore, the use of high-performance computing (HPC) will be necessary to continue using CFD. On the contrary, the GEB models predict the transient behavior of these systems in short times, and one can integrate them in Building Energy Simulation programs. However, the literature about the solar chimney modeling using GEB shows that the transient mathematical model with PCM (six research papers) has been less used than the steady-state model. In general, results of a solar chimney using a PCM show that the temperature variation of PCM and air in the chimney were available for the natural ventilation in evening and night periods. Finally, this review paper is a reference for future research into the field of solar chimneys with a PCM and its applications.