Heat Exchanger units are equipment used to transfer heat between two or more streams of fluids, without actually bringing them together. These ingenious systems are indispensable in a number of industries, improving energy efficiency and reducing heat loss. Thermal exchange operating principle Operating on the principles of thermal exchange, heat exchangers pass along from one fluid to another. Main types are the shell-and-tube, plate and finned-tube heat exchangers which cater to various requirements. Through the enhancement of heat transfer, Heat Exchangers are used in heating, ventilation and air conditioning as well as in industrial processes; they cannot be dispensed with for modern engineering and technology.