Abstract: An evaporation heat exchanger, especially for removing heat from a spacecraft, has a housing formed by an inner cylinder and an outer cylinder which enclose a ring gap between the cylinders. A medium to be evaporated is injected into an evaporation chamber inside the inner cylinder. A cooling liquid is passed through the ring gap. Flow influencing elements are arranged in the ring gap for enhancing the heat transfer onto the inner surface of the inner cylinder for the evaporation. The flow control elements cause an eddy current of the cooling liquid. Additionally, these elements are shaped with interlocking projections and recesses to provide a mechanical coupling between the inner and outer cylinders. This coupling is capable of taking up radially extending forces in a force-locking manner, thereby preventing the bulging of the cylinders, even if the pressure in the ring gap should increase.