Requirements for a Good Heating Material
For a good heating material, the heating element must have fallowing properties:
- It should have a high specific resistance such that a small length of wire (R =ρl/a , ρ =Ra/l ) can produce the required amount of heat.
- The melting point should be high so that high temperature can be obtained.
- The temperature co-efficient should be low as for accurate temperature control, the resistance should be nearly constant at all temperature is possible only if the resistance does not change with changing temperature.
- It should not get oxidized at higher temperatures otherwise its life is reduced and needs frequent replacements.
The most widely used heating elements are either alloy of nickel and chromium or nickel-chromium-iron(Ni-Cr-Fe), nickel-chromium-aluminum(Ni-Cr-Al), nickel-copper(Ni-Cu). Iron can be used as it reduces the cost but it has a drawback that it lowers the life of the element.
Electrical Heating
Heat plays a very important role in our daily life. All heat requirements in our daily lives such as cooking, space warmers, submersion water heaters, and electric toasters, as well as in industrial applications such as fusion, annealing, liquefaction of metals, and solidifying can be effortlessly fulfilled by electric heating, over the other forms of traditional heating.
Heat and Electricity are interconvertible. Heat can be generated by allowing the flow of electricity through the material to be heated. This is termed electric heating; there are diverse approaches to heating a substance, but electric heating is considered significantly superior compared to the heat produced by coal, oil, and natural gas.
When the current is allowed to flow through a conductor, it gets heated up due to I2R losses, and this heating characteristic of the electric flow is employed in industrial and domestic gadgets. This form of heating is also considered safe and efficient as compared to others as most of the electrical energy is converted into heat energy. The regulation of heat is also easy as by varying the amount of potential applied or current supplied more the amount of heat can be generated.
Table of Content
- Heating Effect Of Electric Current
- Devices
- Types
- Requirements for a Good Heating Material
- Design
- Advantages