A heat storage and recovery system and process includes at least one cylindrical external wall, at least one first volume, at least one second volume and at least two fluid injection/withdrawal devices. The first and second volumes are separated by at least one heat storage system comprising at least one bed of heat storage particles. Furthermore, the storage system and the first and second volumes extend substantially over the entire axial length of the cylindrical external wall. The longitudinal axis of the said cylindrical external wall is horizontal.
A system and a process for the storage and recovery of energy by compressed gas include such a heat storage means.