This study deals with experimental work implementing to recover the benefit by changing the shape of the tube in heat exchanger (HE) and improving the heat transfer using water as the working fluid. The experimental tests were carried out in build and design a complete test system for counter flow heat exchanger. The tested system consisting of a copper tube with (1m) length (17.05) mm inner diameter (19.05) mm outer diameter, fixed concentric within the outer tube was made of a material PVC. With an “inner diameter (ID) (43 mm) and outer diameter (OD) (50 mm)” isolated from the outside by using insulating material to reduce heat loss. The modify tube was manufacture containing transverse grooves with the depth equivalent to the half thickness of the copper tube. The distance between the grooves on the outer surface of the copper tube is take as a ratio between (0.5, 1) from the outer tube diameter. The laboratory experiment use the hot water at a flow rate ranging between (1-5) LPM, passes in the inner copper tube. As well as the cooling water with the mass flow rate ranging between (3-7) LPM. Three temperatures were the hot fluid are the adoption of (40, 50 and 60) oC and (25) oC the cold fluid. The experiment result showed that the improvement for temperature difference ranging from (14.94 % to 43.2 %) for both corrugated tubes with respect to smooth tube.
