[b]SOLAR ENERGY[/b]

[attachment=16143]

INTRODUCTION


Solar energy is most important, cheap & abundantly available renewable energy. Sun usually radiates energy in concentration of 1300 watt/m^2.Only a time fraction of total energy is incident on outside of the earth’s atmosphere. As much as 30% of it is directly reflected back to outer space in the form of short wave radiation. Another 47% is directly converted to heat that is lost to the outer space as long wave radiation. Most of the remaining 23% causes evaporation, precipitation and circulation of water in hydraulic cycle of earth temperature of the Sun is about 5500ْ C and at centre of Sun it is about 1 billionْ C.


SUMMARY

Solar energy is the most readily available source of energy. It does not belong to anybody and is, therefore, free. It is also the most important of the non-conventional sources of energy because it is non-polluting and, therefore, helps in lessening the greenhouse effect.

Solar energy has been used since prehistoric times, but in a most primitive manner. Before 1970, some research and development was carried out in a few countries to exploit solar energy more efficiently, but most of this work remained mainly academic. After the dramatic rise in oil prices in the 1970s, several countries began to formulate extensive research and development programmes to exploit solar energy.


Central receivers with heliostat reflectors

.Heliostat are nearly flat faced reflecting mirrors with provision of tracking the sun two planes.

.Several thousand heliostats are mounted on independently tracking

.structures on ground level.Each heliostat should are individual tracking control.
.Reflected rays are focused on to the central receiver mounted on a tall-tower.
.High temperatures are achieved Heliostat
central receiver systems are used for solar thermal-power plants.

.Disadvantage :- The controls are complex and costly.
Collectors cover a very vast ground area.

.Application :- Solar power plant.


When we hang out our clothes to dry in the sun, we use the energy of the sun. In the same way, solar panels absorb the energy of the sun to provide heat for cooking and for heating water. Such systems are available in the market and are being used in homes and factories.


Conclusions

Now a day for huge use of fuel the amount of fuel in nature is gradually decreased and use of fuel has a directly bad effect in nature.So in future Solar energy will be spread in whole world and it is converted a most important energy source .I hope all people will understand our massage and also good effect of Solar energy.