A novel design of tube structure with cosine wave is proposed in this study to investigate effects of wavy surface characteristics on enhancement of heat transfer in a shell and tube heat exchanger, experimentally. All experiments have been designed and carried out on water/water loops. Response Surface Methodology is used to investigate the optimization procedure. Four effective parameters of wavy starting length (0 mm <= b <= 120 mm), hot water flow rates (11 l/min <= Q(c) <= 19 l/min), cold water flow rates (7 l/min <= Q(h) <= 11 l/min) and wavy wavelength (0 mm <= lambda <= 80 mm) in five levels was selected to obtain the maximum thermal performance factor. The results showed that the thermal performance factor reduces by increasing of the hot water flow rate. The thermal performance factor of wave tubes is found to be larger than that of smooth tubs. Optimizing of the procedure indicated that to maximize the thermal performance factor, the lower values of wave starting length and hot water flow rate, and higher values of cold water flow rate and a wavelength of 33.13 mm, must be selected. Also results show that the corrugating process is useful from economic analysis point of view.