Leicester engineers to stress test new technology to store waste heat

University of Leicester engineers are testing materials for a new energy storage system that aims to harness the power of waste heat. 

SEHRENE (Store Electricity and Heat foR climatE Neutral Europe) is an initiative to develop energy storage technology that takes advantage of the properties of phase change materials to store latent heat. 

Led by the Commissariat a L’Energie Atomique Et Aux Energies Alternatives (CEA), and involving partners across Europe, including the University of Leicester, SEHRENE’s new electrothermal energy storage (ETES) concept is designed to store renewable electricity (RE) and heat, and to restitute it as needed. It is very energy-efficient (80-85%), geographically independent and uses no critical raw materials.

Phase change materials (PCMs) will change phase as a function of variations in temperature, such as when H2O changes from a solid (ice) to a liquid (water). When these materials reach the phase change temperature, the heat applied is stored as latent heat at an almost constant temperature. But if their temperature is then decreased, when they change phase back to a solid they will release the latent heat, and provide a lot more energy than other systems which may only store sensible heat (heat that changes the material’s temperature).

The selection of the phase change material for this system will be led by the CEA and based on the thermal properties required for the temperature range that the system will operate within. The team from the Materials Innovation Centre (MatIC), a strategic research and development (R&D) partnership between the University and TWI Ltd, will be testing the performance of the materials in a thermal energy storage environment, and conducting corrosion and ageing studies to ensure that those materials are suitable. 

Funded with £361,326 by UKRI via the Horizon Europe Guarantee, MatIC at the University of Leicester will subject the materials to the effects of corrosion, aging, stress and thermal cycles using molten salt as the PCM. They will then use techniques such as electron microscopy and x-ray diffraction to assess and analyse the corrosion products, and assess damage to the materials.

Dr Shiladitya Paul, Director of the Materials Innovation Centre in the University of Leicester’s School of Engineering, said: “Our role is to understand how construction and phase change materials interact, as relying solely on one without considering the other is not effective. You can have a great phase change material but if it is not compatible with any material of construction that's used, then you have a problem. Likewise, excellent construction materials are rendered ineffective if they are not compatible with available phase change materials. We aim to establish a protocol that aids not only in this project but also extends its benefits to future endeavours, guiding the selection of both phase change and construction materials.”

The electrothermal energy storage technology developed as part of SEHRENE aims to harness heat that would otherwise go to waste. By using the technology to capture heat lost in industrial settings or as part of a geothermal power facility, for example, that heat can be reused or converted into electricity. A 2018 study, not related to the project, estimated UK industrial waste heat to be 391,000 GWh that year. 

Dr Paul adds: “This is an ambitious project that integrates various elements, including a unique heat-pump design aiming to achieve 50% of the theoretical maximum coefficient of performance; an innovative thermal energy storage system with energy density of 90 kWh/m3 ; a 30% increase, featuring phase change material housed within a novel, metallic, Kelvin cells-like foam; and an Organic Rankine Cycle system with engineered operating parameters. Successful implementation of the project could enable 8-12 times longer energy storage duration than current Li-ion batteries, depending on the use case.”

• This project has received funding from the European Union’s Horizon Europe Coordination and Support action under the Grant Agreement no. 101135763 (SEHRENE). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or European Climate Infrastructure and Environment Agency (CINEA). Neither the European Union nor the granting authority can be held responsible for them.
• The University of Leicester received funding for this project from UKRI via the Horizon Europe Guarantee (project reference number 10111825).