Heat Transfer Mechanism and Performance Optimization Scheme of Refractory Oxide Solid Heat Storage Materials

Clean energy advancement drives solid heat storage technology. Refractory oxide solid heat storage materials are widely used due to high-temperature resistance, corrosion resistance, and excellent thermal shock resistance. However, such materials' application is restricted due to their poor heat transfer performance caused by their multi-component multi-phase components and complex structures, and understanding their heat transfer mechanism is crucial to guide performance optimization. Here, by characterizing corundum bricks, high alumina bricks and magnesia bricks, their thermal properties and mechanisms were investigated using heat transfer theories and models. Macroscopic analysis revealed that they are all "internal porosity" materials. By comparing the weighting parameter j, the multi-phase high alumina brick shows poor heat transfer path patency and the measured thermal conductivity is the lowest at 3.55 W·m−1·K−1. Microscopic analysis found that, compared with other materials, phonon intrinsic scattering significantly affects the thermal conductivity of high alumina bricks. Moreover, the corundum bricks and magnesia bricks exhibit a wider range of ultimate heat transfer performance. Hence, the heat transfer performance can be enhanced by increasing particle contact, reducing the negative effects of micro-cracks, phase, impurity, and defect on phonon heat transfer, which provides an optimization scheme for improving the heat transfer performance of materials.