The DIESTA tube is a bimetallic finned tube with an aluminum sleeve fully covering the base carbon steel tube. The outside aluminum fins are embedded into the grooves of the aluminum sleeve. To optimize the air-and tubeside heat transfer performance enhancement structures are applied on both sides. The aluminum fins on the airside combine both a groove and a dimple structure. Airside mechanical qualification confirmed robustness towards fouling, cleaning as well as mechanical strength of the fins equally to standard extruded finned tubes. The tubeside has an internally helical fin structure ensuring an increased of tube side heat transfer coefficient while controlling the pressure drop. DIESTA Technology is a development by the cooperation of Wieland®, TechnipFMC® and Kelvion which also finalized a patent for the groovy fins and inner grooved tubes.