Performance improvement and investigation of radiation heat transfer of chloride salt as high-temperature heat storage medium

Abstract

• Synthesis of carbon doped molten salt composites by reaction method. • High absorptivity material combined with translucent molten salt. • Research on radiation heat transfer based on Finite Element Method (FEM). • Molten salts exhibit good thermal conductivity and radiative properties. The development of solar phase change thermal storage technology is significant for the efficient use of energy. In this study, molten chloride salt was used as a high-temperature phase change thermal storage material to improve the heat transfer performance of the chloride salt by reacting citric acid with sodium chlorite to generate a flaky carbon morphology in the molten salt. The results indicated that the carbon generated by the reaction was uniformly distributed in the molten salt matrix, and the modified molten salt obtained a high latent heat of phase change with a maximum latent heat of phase change of 227.3 J·g –1 , which was 13.7% higher than that of the undoped molten salt, and the maximum thermal conductivity could reach 2.313 W·m –1 ·K –1 , which effectively improved the applicability range. In addition, the combination of ANSYS simulations and the constructed temperature measurement platform showed that the radiation heat transfer effectively improved the temperature distribution of the molten salt in the high-temperature stage. This study may promote the research of the heat transfer behavior of molten salt at high temperature and play an important role in concentrated solar power generation.