Abstract: An arrangement for receiving and/or releasing, in particular storing, thermal energy, including: a container for holding storage material, the container having a first fluid port and a second fluid port for allowing inflow and outflow of fluid flowing through the container in a substantially horizontal flow direction for charging and/or discharging the storage material; at least two first valves at different vertical positions for the first fluid port; at least two second valves at different vertical positions for the second fluid port; and at least two temperature sensors arranged within the container at different vertical positions, in particular in one plane perpendicular to the flow direction.