Concrete Structured Bed Thermal Energy Storage With Direct Contact of the Heat Transfer Fluid
Year: 2026
Type: conference-paper
Abstract: Thermocline thermal energy storage systems based on two separated hot and cold regions in a single tank have been increasingly deployed in order to reduce investment and operative costs. Eni has developed a novel thermocline system based on concrete as storage medium, arranged as structed bed. The heat transfer fluid is in direct contact with the concrete in order to avoid possible concrete spalling and piping detachment affecting heat exchange and thermal efficiency of the system. This work describes the experimental campaign conducted at the Eni’s Renewable, New Energies and Material Science Research Center in Novara in a dedicated pilot plant, which included a 4 m high prototype with a thermal capacity of about 85 kWhth. Moreover, experimental results were used to validate 1D and 3D numerical models. Results showed high round-trip energy efficiency (up to about 97%) and large energy density (45 – 55 kWh/m3). The heating of the concrete in the overall horizontal section was homogeneous without showing the formation of preferential heating paths (e.g., central channels due to inlet nozzle). Moreover, very high reproducibility of tests was observed with no degradation of performance (e.g., reduction of charged/discharged energy) with increased number of cycles.
Institution: Eni (Italy)
Language: English
Subfield: Mechanical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W7223177971