Heat transfer improvement in latent heat thermal energy storage: A review paper

This paper provides a comprehensive review of the current advancements in heat transfer improvement strategies inside latent heat thermal energy storage (LHTES) systems. Enhancement of heat transmission in LHTES systems can be accomplished by modifying the geometric configuration or by enhancing the thermal conductivity. The incorporation of expanded surfaces, such as fins or heat pipes, is a commonly employed technique to enhance heat transfer in LHTES systems. Consequently, this study provides a comprehensive evaluation review of this methodology. Subsequently, an examination was conducted on approaches aimed at enhancing thermal conductivity. The thermal conductivity of the composite phase change material (CPCM) exhibits an increase as the concentration and aspect ratio of the additive is increased. Metallic foam and expanded graphite exhibit notable thermal conductivity and favorable thermo-physical characteristics, while concurrently serving as effective barriers against the leakage of PCM. Encapsulated PCM exhibits significantly improved thermal conductivity and extended lifespan as a result of the presence of a thermally conductive shell. This shell not only enhances thermal conductivity but also serves as a protective barrier, preventing direct exposure of the PCM to the surrounding environment. In this work, an examination is conducted on research that investigates the use of integrated approaches to promote heat transmission. This paper examines the existing research deficiencies in the techniques employed to promote heat transfer in LHTES systems and puts forth a set of recommendations.