Any matter, made up of atoms and molecules, can transfer heat. Heat transfer is nothing but the process of transfer of heat from a body at high-temperature to a low temperature one. According to the thermodynamic system, Heat transfer is defined as the movement of heat across the border of the system due to a difference in temperature between the system and its surroundings. Heat transfer is a discipline of thermal engineering that concerns the generation, use, conversion, and exchange of thermal energy between physical systems. Heat transfer is classified into various mechanisms, such as thermal conduction, thermal convection, thermal radiation, and transfer of energy by phase changes. In general, heat transfer describes the flow of heat (thermal energy) due to temperature differences and the subsequent temperature distribution and changes. The study of transport phenomena concerns the exchange of momentum, energy, and mass in the form of conduction, convection, and radiation. The first is conduction, which occurs in solids or fluids that are at rest, such as this metal bar. The second form of heat transfer is convection, which occurs in liquids or gases that are in motion. And the third form of heat transfer is radiation, which takes place with no material carrier.