The performance of thermally conductive tree-like cast aluminum structures in PCM-based storage units

The thermal performance of a latent heat storage unit was tested during cyclic operation, with LiNO3-KNO3-NaNO3 eutectic as the phase change material. The heat transfer was enhanced by the utilization of a tree-like aluminum structure, cast by means of two combined technologies: polymer 3D printing and investment casting. The mixture of salts was subjected to DSC analysis, to establish the thermal effects during heating and cooling. The unit was tested with and without the enhancer to determine the temperature response and distribution during working cycles (charging–discharging). The experimental outcomes were compared with the results of a numerical simulation performed using the Flow 3D program. To protect the metallic structures from the aggressively corrosive environment of molten salts, they were covered with plasma electrolytic oxidation (PEO) ceramic coatings. The influence of the coating on the heat transfer ability was also evaluated.