Thermal analysis of Mg ₂ Si and Fe ₂ Si ₅ phase change materials for Dish-MGT plants

For Concentrated Solar Power plants, the storage of thermal energy at high temperature is a critical issue. This paper deals with the application of a Phase Change Material integrated in the solar receiver of the Dish-Micro Gas Turbine (DMGT) for the mitigation of solar radiation fluctuation effects on DMGT performance. For this application, the PCM should have a melting temperature between 900 and 1200°C. Even if some promising materials are suggested in literature, the properties of most of them are not fully characterised in the working temperature range. Therefore, this paper presents the experimental results of the thermal analysis of two high-temperature metallic PCMs (Mg ₂ Si and Fe ₂ Si ₅ ). Thermal diffusivity, specific heat capacity and thermal conductivity have been determined using Simultaneous Thermal Analysis (STA) and Laser Flash Analysis (LFA) apparatuses. The thermal expansion behaviour of the samples has been determined up to 1000°C. Furthermore, the compatibility of the PCM samples with the Silicon carbide (SiC) has been also studied up to 1000°C.