Applying investment casting technique for manufacturing thin wall aluminium structures dedicated for heat transfer enhancement in latent thermal energy storage

This research focuses on applying investment casting method for manufacturing thin wall spatial aluminum structures for enhancing heat transfer in latent heat storage. Rapid prototyping procedure was applied for manufacturing structures with use of 3D printing method for disposable patterns to create gypsum precise mould. Castings quality was evaluated in terms of possible casting defects. Moreover thermal performance was evaluated in laboratory scale heat accumulator. Four castings were connected in two heating sections and immersed in phase changing material (PCM) based on nitrate salt mixture. Testing procedure involved multiple melting and solidifying cycles of the PCM to examine long term behaviour of castings in harsh molten salt environment and cyclic mechanical stress from PCM volume expansion during melting/solidifying process. It was found that implementing additional casted aluminium structures in PCM bed can significantly change melting/solidifying characteristics and improve storage charging time.