Fabrication of Heat Storage Pellets Consisting of a Metallic Latent Heat Storage Microcapsule and an Al₂O₃ Matrix

Abstract

Energy efficiency is fundamental in the steel industry. Latent heat storage (LHS) systems with phase change materials (PCM) are attractive technologies for the recovery and utilization of heat, especially for the development of high-temperature thermal energy storage system. This paper describes fabrication of LHS pellets for high-temperature applications using metallic microencapsulated PCM (MEPCM). The LHS pellets consist of Al–Si PCM parts and an Al₂O₃ matrix. The pellets were fabricated by mixing MEPCM with sinterable alumina. The powder mixture was then pelletized and sintered at different pressures and atmospheric conditions, respectively. Some MEPCM in the pellets remained spherical after being sintered at 1000°C, a high-temperature condition above the PCM melting temperature. All fabricated pellets exhibited latent heat of PCM at the melting point of the PCM, about 577°C. The maximum value of latent heat was 73.5 J g⁻¹. This was observed for the LHS pellet pelletized at 20 MPa and sintered under O₂ atmosphere. Therefore, this study presents a great material for high-temperature thermal energy storage systems in the steel industry.