Thermal energy storage system

A device comprising a first heat accumulator and a second heat accumulator, each comprising thermal energy storage containers, each container comprising an insulating enclosure containing earth crossed by at least one first line for a circulation of a first heat transfer fluid and at least one second line for a circulation of a second heat transfer fluid, the at least one first line comprising a first end and a second end, the at least one second line of the containers of the first accumulator being series-connected and the at least one second line of the containers of the second accumulator being series-connected, a heating device comprising a device of thermal energy delivery to the first heat transfer fluid connected to the first and second accumulators by a first circuit for distributing the first heat transfer fluid comprising first and second elements for delivering the first heat transfer fluid and first and second elements for receiving the first heat transfer fluid, the first ends of the at least one first line of the containers of the first accumulator being connected in parallel to the first element for delivering the first heat transfer fluid, the second ends of the at least one first line of the containers of the first accumulator being connected in parallel to the first element for receiving the first heat transfer fluid, the first ends of the at least one first line of the second accumulator being connected in parallel to the second element for delivering the first heat transfer fluid and the at least one second line of the second accumulator being connected in parallel to the second element for receiving the first heat transfer fluid, the first distribution circuit being capable of selectively circulating the first heat transfer fluid in the at least one first line of each container of the first accumulator or in the at least one first line of each container of the second accumulator.