Abstract: A gas turbine unit with auxiliary devices and, in the region of the compressor, a compressed air branch or gas under pressure for the operation of the gas turbine. The compressed air branched off from the compressor, or the gas under pressure, serves for direct drive of an energy exchanger which, while avoiding transmissions and the like, generates the oscillating or rotating movement necessary for driving the auxiliary apparatus of the gas turbine unit or the entire system formed therewith. The energy exchanger has working cylinder chambers, and the associated auxiliary apparatus, embodied as pumps, has displacement cylinder chambers, in which chambers pistons embodied in one piece or rigidly connected with each other are arranged axially movable.