Abstract: The heat exchange comprises a housing of tube-shaped inside cross-section as part of an outer thermal cycle, and at least one tube attached in the housing as part of a second thermal cycle. Each tube is formed from a flexible material. The tubes and housing comprise separate inlets and outlets, and at least one element is disposed transversely to the longitudinal housing axis to fit tightly within the housing crosssection to provide passages for the tubes. The element is shaped as a helix so that the tubes are flowed around in a helical fashion by the medium contained in the first thermal cycle. The helical element forces a flow which passes diagonally at a tangent against and around the tubes.