Abstract: The heat exchanger elements, arranged in a ring around a compressor, gas bine and combustion chamber that have a common axis of symmetry, are supported on a framework having elastic inserts for compensating for or accommodating to thermal stresses and are so connected to an inner and an outer casing portion that free spaces for each of the heat exchanging media (hot exhaust gas and compressed air) are provided inside the unit communicating with the heat exchanger elements. Ducts for the hot gases are surrounded by cooler gases provided in these free spaces to reduce thermal stresses. The casing portions themselves provide some of the duct walls, so that a compact and sturdy unit is provided.