Most of the energy consumed or released by industrial processes is transferred to another system or exchanged with the outside environment. The heat exchanger is therefore a key component in all these thermal energy transfers. Furnaces, ovens and boilers enable the transformation of a material or product through heat transfer. Thermal insulation also plays a vital role in limiting heat exchange during transfer or storage. Controlling the efficiency of industrial processes and their energy costs requires a better understanding of how this equipment works.