As a result of the global energy crisis, which is one of the most crucial problems due to the large and continuous increase in the consumption and the increment shortage of energy resources as well as the high cost, many researchers have performed to increase the efficiency of thermal systems and reduction of the size and thus energy consumption rates. There has been planned work done in last few decades to develop effective heat exchanger which will effect in cutback in requirement of energy and material which will reduces the cost. There are two ways to improve the heat transfer improvement i.e. minimize the thermal resistance by creating turbulence or by improving the effective surface area. Heat transfer enhancement methods exist on three general classifications which are passive, active, and compound techniques. Active methods require external power to input the process; in contrast, passive methods do not require any additional energy to improve the thermohydraulic performance of the system. Also, two or more passive and active techniques can be used together and that is called compound technique, which is employed to produce a higher augmentation than using one passive or active technique independently. Among the passive techniques, insertion of coil is one of the most effective approaches. Coil intensify turbulence and swirl, which are useful factors for heat transfer enhancement. They also provide a longer flowing path (thereby greater area) and longer residence time, thus more efficient heat transfer. A longer flowing path results in larger tangential contact between the flowing stream and tube surface which results in greater frictional loss.