Introduction of Electric Heating
Heating is required for domestic purposes such as cooking and heating of buildings, as well as for industrial purposes such as melting of metals, hardening and tempering, case hardening, drying and welding. Practically all the heating requirements can be met by some form of electric heating equipment. There are many advantages of electric heating over other systems of heating (i.e. coal or oil heating).
Different types of heat transfer
- Heat is produced in different ways in the industries. That heat is utilized in different processes for making a particular job.
- Heat is transferred from higher temperature body to lower temperature body.
- The heat is transferred by three ways i.e. conduction, convection and radiation.
(1) Conduction :
- The heat transferred through a body from one higher temperature to another lower temperature of the body is called as conduction.
- In this process the heat is transferred from one molecule of a substance to the adjacent molecule and so on.
(2) Convection :
- Convection means actual movement of molecule from one place to another.
- The heat is transferred in this process due to the actual motion of the molecules of a fluid.
- The motion of molecules is due to the difference in the fluid density at different temperature levels.
(3) Radiation :
- In this method the heat is transferred without any media.
- In this mode of heat transfer, heating source of material emits radiant energy and other material
- absorbs it, which is to be heated. This process is called as radiation.
- According to the Stephan’s law of radiation,
Classification of electric heating
Advantages of Electric Heating
(1) No pollution
In electric heating there is absence Of the flue gases, smoke and dust. Hence, it does not produce any contamination pollution in the atmosphere.
(2) Clean operation
There is no coal ash, flue gases or smoke etc. Hence, operation is clean and cost of cleaning is very low.
(3) Ease or electric control
Desired temperature can be obtained by automatic control. The temperature control is very simple and easy from full range of temperature.
(4) Uniform heating
Uniform heating is possible with induction heating.
(5) Spot heating
A work piece can be heated to the required depth for heat treatment.
(6) Less attention
Because of automation in electrical heating, wquipment requires less attention in comparison to other types of heating.
(7) Heating of non-conducting materials
electric heating is done to get non-conducting materials heated uniformly throughout the section. This is possible because heat is generated inside the material itself.
(8) Cost of furnaces
Due to the absence of chimney, blower and other equipments electric furnaces are cheaper in initial as well as maintenance cost.
(7) Automatic protection
Automatic protection against over currents or overheating can be provided through suitable switch-gear in the electric heating system.
check it also next important article : Methods | Types Of Electric Heating In Electrical Engineering