Alternate Sources Of Energy-Page 1
Conventional sources of energy
A source of energy that has been widely used for many years is called conventional source of energy.
Eg. The fossil fuels such as coal,petroleum (petrol,diesel,fuel oil etc.),natural gas and electricity from hydro power.The fossil fuels are also used to generate thermal power.
Non- conventional sources of energy
A source on energy from which energy is generated and that can be replenished (renewable) is called non-conventional source of energy(alternate source of energy).
Eg.Solar energy,wind energy,tidal energy,wave energy,geothermal energy,biomass energy etc.
The present non-conventional sources of energy like wind energy,solar energy etc.were conventional sources before the invention of steam engine.Man had used these sources in propelling ships,wind mills for grinding corns and pumping water.
Solar energy and its applications
Sun produces enormous amount of energy due to thermonuclear reaction.This energy is radiated in the form of wave packets called photons.Solar energy travels 150 million kms. to reach the earth.The quantity of solar energy reaching the earths atmosphere is 1.36kw/sqm in 12 hrs.This energy is harnessed using solar collectors.Solar collector is a device used to collect heat by absorbing sunlight.It is utilized for
a)heating water
b)cooking food
c)drying of food items
d)seasoning of wood
e)desalination of marine water
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| Bowl type solar collector |
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| Flat type solar collector |
A flat type solar collector is used in water heater and bowl type in cooking.Solar collectors are also used in desalination plants to generate electricity by producing steam.
Solar pond
Solar pond is a large-scale solar collector.A solar pond contains a layers of salt solution with increasing salt concentration in the direction from top surface to bottom.When sunlight is absorbed by the solar pond the difference in density prevents the heat in the lower layer moving upwards.As a result,the temperature at the bottom layer rises over 90º C.This heat is tapped for desalination,electricity generation etc
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Solar pond in Bhuj,in Gujarat