ELECTRIC HEATERS FOR MOLTEN SALT STORAGE SYSTEMS

Kurzfassung

Molten salt thermal energy storage systems (TES) are a key technology for integrating variable renewable electricity into industrial heat and power supply. They address the temporal mismatch between fluctuating renewable generation, such as wind and solar, and steady industrial heat and power demand. The integration of electrically charged molten salt storage into industrial infrastructure has shown significant potential for cost effective decarbonization of both power generation and industrial heat supply, with power-to-heat being identified as a key factor. In these systems, the electric flow heater represents the critical interface between the power grid and the TES. Yet its design and the systematic comparison of electric heating technologies for molten salt environments, which are commercially available and currently under development, remains largely unaddressed in the open literature. This work closes this gap by classifying available electric heating technologies and evaluating them against application-specific requirements such as heat flux density, installation space, and voltage level. MgO-insulated tubular flow heaters are identified as the current state of the art. Their limitations, such as limited module size and low voltage operation requiring costly transformer infrastructure and large cable cross sections, motivate the search for improved designs and alternatives. Building on this classification, the presentation introduces a methodological framework for the systematic evaluation of electric heating technologies under realistic molten salt operating conditions. An analytically based heat transfer model, validated against a real world molten salt heater, is used to illustrate how physical constraints and geometric design parameters influence heater performance. First examples are presented to provide insight into relevant design parameters such as heater diameter, insulation thickness, and heating element dimensions, as well as the dominant physical limitations governing commercial heater concepts. This work presents the first structured analysis of commercial and potentially commercially feasible electric heating technologies for molten salt storage systems. It establishes a methodological basis for future quantitative technology comparison and design optimization of electric heaters. Improved heater concepts have the potential to reduce system costs and thereby support the broader integration of variable renewable energy into industrial heat and power supply.