Enhancing solar façade thermal performance with PCM spheres: A CFD investigation

Abstract

To improve building energy efficiency and address thermal storage challenges during periods without a heat source, such as cloudy weather or night-time, a range of solutions is required. Innovative technologies and sustainable practices are essential for combating climate change and reducing carbon emissions. This study primarily focuses on Thermal Energy Storage (TES) systems, specifically those using Phase Change Materials (PCMs), to increase energy efficiency for Transpired Solar Collectors used in buildings applications. During the last 30 years Transpired Solar Collectors (TSC) have been extensively investigated. However, a primary concern still exists regarding thermal storage when the heat source is unavailable, such as during periods of cloudy weather or at night. Thus, a Thermal Energy Storage (TES) system coupled with the TSC is a potential solution. In this study we are investigating using numerical simulation the arrangement of encapsulation for TES, integrating phase change materials (PCM) in spherical elements when compared with plate encapsulation elements. The model reproduces a part of a real scale thermal energy storage inserted in a Double Skin TSC. The model consists of a Plexiglas duct in which four different arrangements for the spherical encapsulated PCM were studied. For each of the arrangements the heat transfer between the TES elements and the air passing through the collector was analyzed. The primary finding of the study indicates that the hexagonal arrangement offers better passive airflow control, thus enhancing the heat transfer up to 12.3% compared to the rectangular arrangements

Harnessing Nanomaterials for Enhanced Energy Efficiency in Transpired Solar Collectors: A Review of Their Integration in Phase-Change Materials

“…There are several methods for storing thermal energy, with the main ones being sensible heat storage [18,19] and latent heat storage [20][21][22][23]. Sensible heat refers to the quantity of heat that is either added to or extracted from a material when its temperature changes.…”

“…Several geometrical designs for PCM integration in TSC have lately been investigated. The incorporation of PCMs in spheres [22,51] is viewed as the optimum solution in terms of the unitary distribution of the flow and the size of the heat exchange surface. Furthermore, the TSC configuration can be refined with additional improvements by providing a mobile insulating blanket consisting of materials with very low heat conductivity, such as aerogel, as Calota R. suggests in a research grant report [61].…”