Experimental investigation of high temperature organic phase change materials for waste heat recovery

• Two organic PCMs embedded in 3D periodic structures were experimentally compared • Structure and material properties significantly impact PCM thermal performance. • Erythritol exhibits significant subcooling unlike the other organic PCM • Optimized thermal storage design should consider PCM properties This paper compares the performance of two high temperature organic phase change materials during solid/liquid phase change to study the effects of 3D printed periodic structures in enhancing the heat transfer performance. The experimental results reveal that erythritol and an organic material, P130 respond differently to the same thermal stimuli, emphasizing the importance of this analyses to highlight the underpinning heat and mass transfer mechanisms. It can be stated that the phase change materials present peculiar heat transfer characteristics and one of the main challenges is represented by the difficulty in identify a general thermal behaviour (latent heat storage capacity, heat transfer characteristics, material’s response to possible enhancement strategies, etc.) even within the same family of materials. This work confirms that the design of the latent thermal energy storage must be tailored around the specific application and that the thermal conductivity of the phase change materials does not deeply affect the need of the use of enhanced surfaces. In fact, only enhanced surfaces can permit to design efficient and effective latent thermal energy storages that meet the heat load demands.