Heat exchanger (shell & tube, coil, plate, U tube bundle, double pipe, float type exchangers) is used to control a systems or substances temperature by adding or removing thermal energy.

                   Although heat exchangers are in many different sizes, levels of sophistication, and types; all the heat exchangers use a thermally conducting element usually in the form of a tube or plate to separate two fluids, such that one can transfer thermal energy to the other.