Innovative filler successfully deployed in one-tank molten salt energy storage system
The progressive expansion of renewable energy sources also leads to fluctuations in energy supply. This is often not in line with demand, which also fluctuates.
One solution is high-temperature heat storage based on molten salts, which decouple supply and demand in thermal processes. These have been used successfully in commercial solar thermal power plants for more than 10 years. The technology can also be used in local chemical or power plants for flexibility. The principle is very simple: to store energy, molten salt is heated from 300°C to 560°C and stored in two separate tanks.
DLR is researching a novel single-tank storage concept in which the 'hot' and 'cold' molten salt are stored together in one tank. This works because of the different densities of the molten salt, with the hot salt being up to 10% lighter than the cold salt. In general, the single-tank concept has several advantages, such as less space requirement, omitting one tank, cheaper pumps, avoiding a large volume of gas and lower heat losses. For this reason, DLR operates a large-scale facility, the Test Facility for Heat Storage in Molten Salt (TESIS:store).
Top view into the uppermost packing insert with Kraftblock filling material. Credit: DLR (CC BY-NC-ND 3.0) |
DLR is currently conducting a research project with project partners Kraftblock, Universitat Politècnica de Catalunya-BarcelonaTech (UPC), SPF Institut für Solartechnik - Ostschweizer Fachhochschule (OST) and Empresarios Agrupados Internacional (EAI). The project, called Newcline, will investigate the single-tank concept with a filler using the TESIS:store system. The filler can save a considerable amount of salt, which significantly reduces the overall costs. Together with project partner Kraftblock, new fillers based on structured ceramic fillers have been developed and are now being tested in the plant. After weeks of preparation, the inserts equipped with the filler were lifted into the plant on 26.10.2023. Extensive tests with variable boundary conditions are now planned for the coming months.
About NEWCLINE
The research project NEWCLINE (Advanced thermocline concepts for thermal energy storage for CSP) aims to explore a novel single-tank storage concept where hot and cold liquid salt are stored together with a filler in one tank, saving space and enabling significant cost savings. The project will develop new fillers and storage solutions based on structured ceramic fillers and latent heat storage materials to stabilise the outlet temperature of the storage tank.
Funding Agency: Federal Ministry of Economic Affairs and Climate Action, Contract number 03EE5057A
Project partners: Kraftblock, Universitat Politècnica de Catalunya-BarcelonaTech (UPC), SPF Institute for Solar Technology - Ostschweizer Fachhochschule (OST) and Empresarios Agrupados Internacional (EAI)
Duration: 01.12.2020 to 31.05.2024
Links:http://newcline.eu/, to TESIS:store:Institute of Engineering Thermodynamics - Thermal Systems for Fluids (dlr.de)