Cross-Cutting CFD Support for Efficient Design of a Molten Salt Electric Heater for Flexible Concentrating Solar Power Plants

Abstract

This study focuses on the optimization of an electric heater design for molten salt pre-heating in a supercritical CO2–molten-salt loop. The scope of the investigation is to analyze typical designs of similar components for identifying possible malfunctions and defining proper modifications in the geometry and operating conditions to address such technical issues and optimize the attained thermal efficiency. By performing computational fluid dynamics simulations for reference designs of such components, two particularities pertinent to the temperature distribution are identified as the most likely ones: the development of hot spots and thermal stratification. As a further step, new designs and operating conditions are proposed and their effects on eliminating the hot spots and stratification development phenomena are evaluated. It is shown that the homogeneous distribution of heat flux density across the heating elements is the most favorable option for avoiding the development of hot spots, while the mitigation of thermal stratification is possible through the development of turbulent flow. The proposed design and operating conditions are expected to facilitate the optimization of molten-salt electric heater operation and promote the development of next-generation molten-salt–supercritical-CO2 concentrating solar power plants.