Over the last few decades, Energy saving has been a major concern in every process Industry. A slight saving in Energy can benefit in crores of money. Energy savings are of primary importance in the design of Heat exchangers leading to more efficient and Environment friendly devices. The book summarizes the comprehensive research on Heat Transfer Enhancement using a new technique using TMT rods as inserts. Enhancement is a practice of modifying the surface to increase the heat transfer coefficient between the surface and the fluid. Experiments were carried out under two conditions of Rod inserts with and without baffles in the tube side flow of a double pipe heat Exchanger and the results are compared with a smooth tube DPHE. Rod inserts act as a turbulence promoter. It mixes the boundary fluid and the bulk fluid and thus reduces the boundary layer thickness. The effect of inserts on the heat transfer coefficient and the pressure drop were investigated at different flow rates. This technique can enhance the heat transfer coefficient by about 2.5 times with a very low fabrication cost.