Thermocline heat storage (stratified tank) is an industrial solution for recovering waste heat and integrating intermittent energy sources. However, its performance remains limited by poorly controlled phenomena: non-uniform fluid distribution, partial thermal cycling, and real-world operating conditions (fluctuating inputs, incomplete cycles).
The proposed doctoral research builds upon the PhD work of Alexis Ferré and the postdoctoral research of Martin Rudkiewicz, which focused on the modeling and characterization of thermocline storage systems. These studies led to the development and validation of a comprehensive physical model implemented in ANSYS Fluent, enabling detailed investigation of the physical phenomena governing the formation and subsequent transport of the thermocline within a storage tank.
A partially validated CFD numerical model, together with a fully operational experimental facility, will therefore constitute the foundation of this PhD project. The main objectives are:
• to further advance the experimental characterization of liquid thermocline storage behavior, with particular emphasis on the influence of flow distribution (including distributor type and design parameters), thermal cycling, and initial conditions on storage performance;
• to validate the CFD physical model against newly acquired experimental data;
• to reduce the high-fidelity CFD model to a comprehensive system-level model incorporating the distributor, the storage tank, and the extraction process;
• to provide the scientific and industrial communities with currently unavailable datasets that are essential for model validation under varied and realistic operating conditions.