Test Facility for Thermal Energy Storage in Molten Salt (TESIS:com)

The Test Facility for Thermal Energy Storage in Molten Salt (TESIS) at the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) DLR Institute of Engineering Thermodynamics in Cologne is the first research facility for molten salt storage and technology at a significant scale in Germany. This large-scale research facility is used to develop and improve thermal storage capabilities and the molten salt technology that is used to store energy produced from renewable sources.

The test facility trials technology on the scale of one megawatt hour – far beyond the energy levels reachable in a laboratory. As such, research here takes place under conditions representative of those in real-world industrial applications. These applications include energy-intensive industrial processes such as the production of steel, iron, non-ferrous metals, glass, cement and chemical products. Molten salt storage can increase the energy efficiency of these processes. It can also be incorporated into power plant technology to stabilise fluctuating and volatile power generation from renewable energy sources. Molten salt storage systems are already being used commercially for demand-driven power generation in solar thermal power plants. These thermal storage systems can also be integrated into conventional fossil fuel power plants to improve their flexibility or to convert them into heat storage power plants.

TESIS:com – qualification of components and process engineering for molten salt

TESIS is a twin programme consisting of two subsystems – TESIS:com and TESIS:store. TESIS:com is used to qualify new components of molten salt infrastructure and to resolve process engineering issues. The subsystem allows these components to be set up and reconfigured in a flexible way, and controllable temperature and mass flow rate facilitate the creation of fully automated test programmes.

This large-scale research facility enables researchers to conduct tests under defined and even extreme operating conditions in a protected area fitted with safety equipment within an air-conditioned building. The purpose of the facility is to qualify and improve molten salt technology for use in thermal storage systems. TESIS:com is also being used for the ongoing development of salt analysis technology and the investigation of process engineering issues such as freezing and overheating processes in molten salt.


Volker Speelmann

Head of Research Infrastructures
German Aerospace Center (DLR)
Executive Board department for Innovation, Transfer and Research Infrastructure
Linder Höhe, 51147 Cologne

Thomas Bauer

German Aerospace Center (DLR)
Institute of Engineering Thermodynamics
Linder Höhe, 51147 Cologne