Heat transfer enhancement in phase change materials for thermal energy storage in concentrated solar power plants

The increasing drive to save the planet from accumulating greenhouse gas emissions has resulted to increased search for new technologies in sustainable energy. Renewable energy technology, particularly concentrated solar power plants are mature but still unreliable especially during the periods of no irradiance from the sun. However, incorporation of thermal energy storage systems make them reliable. Latent thermal energy storage systems using phase change materials are highly thought for this application due to their high energy density as compared to their sensible heat counterparts. They, however, suffer from low thermal conductivity and thus take long to charge/discharge. In this study, a cheap but relatively efficient metal insert was used to enhance heat transfer as compared to the expensive commercially available metal foams/graphite foams. Results obtained in ANSYS Fluent 19.2® numerical solver show about 30% improvement in heat transfer when a 70% porous metal insert is used in melting. In solidification, on the other hand, for the same porosity, over 80% improvement was noticed as compared to a non enhanced case (pure phase change material).