Recuperator for the transfer of thermal energy from a first gas flow to a second gas flow, comprising: - at least one first connection, by which the first gas flow can be fed to the recuperator, - at least one second connection, by which the first gas flow can be discharged from the recuperator, - at least one third connection, by which the second gas flow can be fed to the recuperator, - at least one fourth connection, by which the second gas flow can be discharged from the recuperator, - a first group of channels with two end regions (11a, 11b), wherein in a first operating position the first end region is connected to the first connection and the second end region is connected to the second connection, and wherein in a second operating position the first end region is connected to the fourth connection and the second end region is connected to the third connection, - a second group of channels with two end regions (12a, 12b), wherein in a first operating position the first end region is connected to the third connection and the second end region is connected to the fourth connection, and wherein in a second operating position the first end region is connected to the second connection and the second end position is connected to the first connection, - at least one switching means, by which the groups (11, 12) of channels in each case can be switched from the first operating position to the second operating position or vice versa, wherein the switching means comprise a drum rotatably mounted about an axis of rotation, in which the first group of channels and the second group of channels extend, wherein the drum is rotatable into a first drum position, which corresponds to the first operating position of the groups of channels (11, 12), and wherein the drum is rotatable into a second drum position, which corresponds to the second operating position of the groups of channels (11, 12), characterised in that the first group of channels and the second group of channels are located as central heat exchanger inside the drum, wherein the plurality of channels of the two channel groups and of the central heat exchanger, which channels are separated from each other by heat-conducting walls, can be flowed through in opposite directions. - at least one first connection, by which the first gas flow can be fed to the recuperator, - at least one second connection, by which the first gas flow can be discharged from the recuperator, - at least one third connection, by which the second gas flow can be fed to the recuperator, - at least one fourth connection, by which the second gas flow can be discharged from the recuperator, - a first group of channels with two end regions (11a, 11b), wherein in a first operating position the first end region is connected to the first connection and the second end region is connected to the second connection, and wherein in a second operating position the first end region is connected to the fourth connection and the second end region is connected to the third connection, - a second group of channels with two end regions (12a, 12b), wherein in a first operating position the first end region is connected to the third connection and the second end region is connected to the fourth connection, and wherein in a second operating position the first end region is connected to the second connection and the second end position is connected to the first connection, - at least one switching means, by which the groups (11, 12) of channels in each case can be switched from the first operating position to the second operating position or vice versa,