Solar energy
Solar energy is emitted from the sun due to the various thermonuclear reaction (nuclear fusion reactions occurring at very high temperature) taking place on the sun.
It is the main source of energy for other non-conventional sources like wind tidal and ocean thermal energy depends on it. total solar energy absorbed by the earth and its atmosphere is 3.8 × 24 J\ year which is more than the energy of all the coal reserves taken together.
Flat plate collectors are most commonly used in solar energy collectors. These are simply cheap and easy to construct it consist of rectangular troughs having a network of tubes of flowing water covered by absorbing surface and glass sheet. The absorbing surface absorbs solar rays and uses it to heat the Solar energy
water tubes below it the glass sheet prevents the escape of heat from the water and absorbing material are insulated to minimize heat loss.
Apart from flat plate collector solar power tower, solar furnace, solar cells etc are used to trap solar energy for various purpose Cyprus is the world’s largest user of solar energy.65% of domestic hot water in Israel is provided by solar energy.
Uses of solar energy
- Solar energy is used to melt steel, prepare nonmaterial’s etc. by using the solar furnace.
- Solar energy is used to disinfect water.
- It is used for desalination of seawater.
- It is used to heat water for power generation using solar ponds.
- It is used for cooking food in solar cookers.
- It is used to power solar cells for running various appliances like vehicles calculators mobile phones street lights etc.
Advantages of solar energy
- It is a renewable and inexhaustible source of energy.
- It is freely available at all consumer premises.
- It can be used globally without depending on rain, tide, wind etc.
- It is non-polluting, hence does not give rise to greenhouse gas. Solid waste like ash or radioactive wastes is not generated.
- Solar thermal power plants are best feasible in the desert and dry sunny area where another source of energy is not available.
Disadvantages of solar energy
- It varies with geographical and climatic conditions.
- A large area is required to construct a solar tower or solar ponds due to low energy density 0.1 to 1kw\m2.
- Solar power plants are not varied economical as the energy conversion is costly.
- Hybrid plant and efficient energy storage systems are very essential for the continuous supply of energy during the night.
- The angle of incident of sun rays changes continuously making its collection difficult.
