Heat Transfer Operation ( Heat Exchanger ),Conduction , convection , Radiation , Importance of heat transfer

                    -: Heat Exchanger :- 

Heat :-  Heat energy is the form of energy which transfer this energy from one body or system to another system or body.
 Convection heated particles transfer heat to another substance, such as cooking something in boiling water. 
Radiation is when heat is transferred through electromagnetic waves,such as from the sun.

" A Heat Exchanger is a device, which is used for transfer of following heat from one fluid to anther through a separating wall."The Heat Exchanger equipment involve heat energy transfer either by conduction, convection or by radiation mode.

                                         A wide variety of heat exchanger are employed in process industries for specific purpose. The choice depend upon many factors such as the process variable, operating cost, available space etc. As the name itself implies these equipment fraction by exchanging heat between two fluids either indirect contact with each other of reported by a solid wall.

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     The Heat Exchanger commonly known as boiler, condenser power industry, radiator in processing industry, equipment in chemical industry and many others.When the Heat Exchanger is to be designed for a particular application, the following consideration are almost always taken into account.

• Thermal analysis and transfer requirement.
• The preliminary mechanical design.
• Design for manufacturer.
• Pressure drops characteristics.
• Physical size and cost.

Heat is transferred by three different methods:- Conduction, Convection, and Radiation.

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• Conduction :-  It is heat transfer through stationary matter by physical contact. The matter is stationary on a macroscopic scale—we know there is thermal motion of the atoms and molecules at any temperature above absolute zero.

Heat transferred between the electric burner of a stove and the bottom of a pan is transferred by conduction.

Example : Heat transfers into your hands as you hold a hot cup of coffee.

• Convection :- It is heat transfer by the macroscopic movement of a fluid. This type of transfer takes place in a forced-air furnace and in weather systems . 

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Example : Convection Heat transfers as the barista steams cold milk to make hot cocoa.

• Radiation :- Heat transfer occurs when microwaves, infrared radiation, visible light, or another form of electromagnetic radiation is emitted or absorbed. An obvious example is the warming of the Earth by the Sun. A less obvious example is thermal radiation from the human body.

  

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Example : Radiation Reheating a cold cup of coffee in a microwave oven.

Importance of heat transfer :- Heat a concept that is important to understand in various engineering fields. It is particularly relevant for civil, mechanical and chemical engineers because heat transfer plays a key role in material selection, machinery efficiency and reaction kinetics, respectively.