In the context of an electricity mix with a high proportion of intermittent renewable energy sources, massive energy storage solutions will be of major interest. For the vast majority of these solutions, electricity is converted into energy that can be stored on a large scale (e.g. pressure energy, chemical or electrochemical energy, etc.), then converted back into electricity. Losses occur during each of these stages (conversion, storage), so the efficiency of the complete system is an important issue and requires a good understanding of each conversion and storage stage.
The innovative system that we want to study is a Carnot battery, i.e. a thermal battery associated with thermodynamic conversion cycles (electrical energy to thermal energy to electrical energy). The anticipated advantages are numerous: the possibility of integrating thermal flows, the absence of geographical constraints, a degree of freedom in the choice of temperatures and storage materials, the use of alternators for inertia, etc. The identified challenges are reactivity and overall efficiency.
The research will focus on the charging cycle (very high temperature heat pump) and its coupling with thermal storage, initially from a static and then a dynamic perspective. Unsteady numerical modelling will be developed and used to design the Carnot battery system. Tests carried out on an experimental installation at the CEA will be used to validate and enhance the modelling results.