Heat exchanger barrier ribbon with polymeric tubes

Heat exchanger structures for conducting fluid are provided in the form of multiple spaced-apart polymeric tubes embedded in foil laminate which includes metal and at least one polymer. Useful polymers are polyolefins, polyesters and polyamides. The metal provides barrier protection making the structure suitable for refrigeration uses as well as providing an extended heat transfer surface between the tubes for when the elements are used for heat transfer, and the polymer on the foil permits it to be sealed closely around the tubes to improve heat transfer. The tubes are of a geometry which provides burst strength, so that the metal can be quite thin.