Comprehensive experimental analysis of igneous ultra-mafic rocks as thermal energy storage materials

Natural rocks have aroused great interest as available, cost-effective and eco-friendly materials for energy storage, mainly as filler materials in packed-bed systems. In this light, natural Moroccan igneous ultramafic rocks (peridotites and serpentinites) were selected for investigating their suitability as thermal energy storage materials (TESMs). This study examined the most relevant properties and characteristics, which indicate the potential of igneous ultramafic rocks as TESMs. At the same time, the effect of rising temperature on specific heat capacity, thermal expansion, thermal diffusivity and conductivity, as well as thermal stability of rocks have been investigated. The main findings reveal that both studied rocks have suitable thermo-physical properties, even though peridotite sample exhibits the highest thermal capacity (up to 4.912 MJ/m3.K at 540 °C) and hence the highest potential to be used as TESM in storage applications at high temperatures up to 500 °C.