A study on heat transfer characteristics of quinary molten salt mixture

In this study, experimental analysis of the heat transfer characteristics of a quinary molten salt mixture was carried out. This mixture was developed at Korea Institute of Energy Research as a heat storage material for a solar thermal power plant. Experiments were conducted to obtain the heat transfer coefficient in a vertical tube and to generate steam in a heat exchanger. To obtain the heat transfer coefficient, the temperatures of the outer wall, inlet, and outlet were measured in upward molten salt flow. Heat transfer correlations were proposed for the molten salt based on experimental data. The accuracies of the correlations were 60% and 88% for the transition and turbulent flow regions, respectively, with an error range of ±20%. A concentric heat exchanger was used for steam production to use the molten salt for power generation. Superheated steam at 100 bar and 400 °C was generated through heat transfer between the high temperature molten salt and water, with an efficiency of 81-91%.