April 23, 2024

Industry as a guest at MOPUW: Advanced heat storage campaign launched

Industry as a guest at MOPUW
The high-temperature heat storage elements of industrial partner ENERGYNEST are connected externally to the mobile pump and heat transfer fluid test facility for the validation tests.
  • The MOPUW mobile pump and heat transfer fluid test facility at the DLR site in Cologne offers opportunities for the technical qualification of key components for the industrial energy transition.
  • The test facility is attracting increasing interest from industry resulting in the launch of the first industrial campaign.
  • The so-called ThermalBatteriesTM, high temperature heat storage elements of the company ENERGYNEST, are to validate and confirm their ability to withstand thermal shocks beyond current technical specification.
  • The storage elements are charged and discharged with steep temperature ramps using heat transfer fluid conditioned by MOPUW at temperatures of up to 400 degrees Celsius.
  • With their buffer function thermal storage systems play an important role in the transition from a fossil to a renewable energy supply for industry.

DLR and industry partner ENERGYNEST intend to obtain practical and operational experience working with the mobile pump and heat transfer fluid test facility MOPUW for new heat transfer fluids and high-temperature thermal storage equipment.

ENERGYNEST’s solid-state thermal storage elements (ThermalBattery™) are charged and discharged by heat transfer fluid provided by MOPUW at controlled temperatures up to 400 degrees Celsius with defined temperature ramps. This is to verify their ability to withstand thermal shocks far beyond current technical restrictions.

External extension with thermal storage setup

In the current campaign, the outdoor area of the MOPUW test facility at DLR in Cologne will for the first time be used for operating and testing technology from an external thermal energy storage company. Extensive system configurations can be connected and operated at the area without the spatial restrictions of the test container itself. The control system of the test facility has been upgraded as part of the project to provide connections to external sensors for flow and temperature and autonomous operation with defined temperature ramps and gradients of the heat transfer fluid (HTF). Thermal charging and discharging of individual elements of the ThermalBattery™ can with this system be subjected to accelerated testing. Furthermore, the silicone based HTF used in MOPUW can be operated at 450 degrees Celsius for thousands of hours, which is significantly higher than for other HTFs on the market.

„We recognize DLR, with its long experience in innovative and high performance HTF, to be among the most competent research institutions in this field. We expect that this highly flexible state-of-the-art test facility will provide us valuable experience with reliable results from operating our thermal elements with a new more environmentally friendly HTF for potentially broader applicability”, says Nils Høivik, VP Technology & Research at ENERGYNEST.

Heat storage as a building block of a renewable energy supply

To support and enable the energy transition in accordance with the principles of the European Green Deal increasing the share of renewable energy sources in the grid and industrial processes, intermediate energy storage is necessary and part of the overall solution. In particular, thermal energy storage technologies are needed by industrial consumers to secure the supply of clean and green heat on demand 24/7. Buffer storages used for this purpose are thus essential to transition from fossil to renewable energy supply. By storing and supplying green electricity, heat and steam as needed, CO2 emissions can be reduced, and security of supply increased at the same time. Various storage technologies are commercially available depending on the required temperature, energy source and consumer. When sufficient or excess green energy is available, thermal energy storage systems can be charged with heat transfer fluids at high temperatures, for example, until they are fully charged, i.e. they have absorbed the heat of the oil. Later, cold oil flows through the system in reverse and they are discharged, releasing the heat back into the fluid and making the heat available on demand where it is needed.

External testsetup at MOPUW
The charging and discharging of ENERGYNEST's ThermalBatteryᵀᴹ is made possible by providing heat transfer fluid from the MOPUW test facility.

Thermal storage technology and demonstration environment

The Norwegian company ENERGYNEST is the developer and manufacturer of modular, scalable, solid-state, high-temperature thermal energy storage systems marketed under the name ThermalBattery™. These systems can store and supply thermal energy in form of steam or direct heat to industrial processes typically operating at temperatures between 150 and 400 degrees Celsius. The individual modules in the system are sized like 20-foot shipping containers with thermal storage capacities of up to and exceeding 1.5 MWh, which offers a scalable system design with total installed capacities ranging from 5 to more than 1,000 MWh.

The mobile pump and heat transfer fluid test facility MOPUW enables the demonstration and research of new and more environmentally friendly heat transfer fluids. At the same time, typical components of the heat transfer fluid system such as pumps, heaters or externally attached thermal energy storage components can be specifically tested there in technically relevant sizes. For this purpose, the pump test facility supplies them with heat transfer fluid at controlled temperature, flow and pressure.

„We are pleased that the MOPUW test facility, which was designed, built and operated for the first time as part of the SING research project, is attracting interest from industry. In fact, predicting the future demand and the relevant issues is one of the biggest challenges in the design of such test facilities“, reports DLR project manager Nicole Janotte.

Project SING

Scientists from the Institute of Future Fuels operate the MOPUW test facility as part of the SING project (Silicone Fluid Next Generation). The primary goal of the project is to reduce the electricity production costs of solar thermal parabolic trough power plants. DLR is the project coordinator and meanwhile owner of the plant. Other project partners in the SING project are DICKOW Pumpen GmbH, WACKER Chemie AG, flucon, TÜV NORD and Senior Flexonics. Associated partners are heat 11, Flagsol, Rioglass, RWE, STEAG and the Spanish research centre CIEMAT on behalf of DLR.

The project is funded by the German Federal Ministry for Economic Affairs and Climate Action.


Dr. rer. nat. Christian Jung

Head of Department
German Aerospace Center (DLR)
Institute of Future Fuels
Chemical und physical fundamentals
Linder Höhe, 51147 Köln-Porz

Christian Siegel

Communication Officer
German Aerospace Center (DLR)
Institute of Future Fuels
Schneiderstraße 2, 52428 Jülich
Tel: +49 (0) 2461 93730-328