Experimental characterization of a molten salt based thermal energy storage systems for industrial process heating

Background

Process heat represents 37% of the total industrial energy demand in the EU, with a significant share of fossil fuel-based energy sources. In this context, the food and beverage sector constitutes one of the largest consumers of process heat in the temperature range between 100-500°C and therefore is a key sector for decarbonization. The current industrial process heat demand is primarily covered by fossil fuel sources with a small share of sustainable renewable energy sources.

Molten salt–based thermal energy storage (TES) systems are high-temperature heat storage technologies that store thermal energy in the form of sensible heat using molten inorganic salts—typically mixtures of nitrates, nitrites, or chlorides. They are gaining attention for industrial process heating (IPH) applications due to their ability to operate at medium to high temperatures (200–800 °C), stability, and cost-effectiveness. TES systems with molten salts store energy by heating the salt during charging and release it during discharging to supply heat for industrial processes, typically operating in two tank configurations.

• Charging mode: Thermal energy input raises the salt temperature.

• Discharging mode: Molten salt transfers stored heat via heat exchangers to a working fluid

Objective and goals

The primary objective of the thesis is to support the activities towards establishment of a fully functioning molten salt based thermal energy storage facility and develop a lab-based charging & discharging test setup.

Methodology

Rig commissioning of molten salt based thermal energy storage system is to be undertaken in the Laboratory of heat and power technology at the Dept. of Energy Technology.

• Procurement of sensors, valves and auxiliaries and performing their calibration.

• Experimental activity by supporting with the setting up of control systems for the thermal energy storage flow loop data logging with flow, temperature and pressure sensors.

• Prepare a test setup for charging of the storage system from hot tank to cold tank and record measurements.

• Prepare a test setup for discharging of the storage system from cold tank to hot tank and record measurements.

• Perform repeatability of tests and validate the results.

Expected outcomes

The work is anticipated to offer:

• Hands-on experience with the setting up of thermal energy storage system for high-temperature process heating applications.

• Working with sensors, controls loop and building an understanding of the salt flow operations. 

Deliverables

The main deliverables of the project include:

• Final project report and presentation.

Timeline

January 2026 – June 2026 (flexible)

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