Wednesday, May 8, 2013

Solar Energy from Sun

The solar energy is the light and heat radiated from the Sun.  It has been used by humans since ancient times,  Some of the solar energy technologies include solar water heating, solar electricity, solar artificial photosynthesis etc...  These technologies make significant contributions in solving the most urgent energy problems the world especially India faces now.

Our Earth receives about 174 petawatts (1 petawatt = 1015 watts)  of solar radiation at the upper atmosphere.  Nearly 30% of this energy is reflected back to space while the rest of it is absorbed by clouds, oceans and land masses.

Green plants convert solar energy into chemical energy which produces food, wood and the bio mass.   The total solar energy absorbed by Earth' s atmosphere, oceans and land masses is approximately 3,850,000 exa joules ( 1 exa joule = 1018 joules) per year.   The amount of solar energy reaching earth's surface in a year is so vast that it is twice as much as the energy that is obtained from all of the Earth non-renewable resources of coal, oil, natural gas etc.

 Applications of Solar Energy

Solar energy is the light and heat radiated by the Sun.  The solar energy that reaches the surface of Earth can be used for producing electricity or heat through the use of solar collectors.
For example a closed car can be viewed as a solar collector - the light energy which passed through the window glass of the car is absorbed inside the car and converted into heat.  The amount of solar energy falling on an area of the size of a basket ball field, in thermal energy terms is equal to about 650 barrels of oil in a year. Solar energy is a renewable energy whose use does not affect the future supply.

The solar energy can be categorised in two ways - Heat and Light.  The solar energy is used by us in many ways everyday.  For example when we hang the laundry outside to dry in the sun light, we are using the solar heat for drying out clothes.  The plants make their food in presence of sun light.  If there is no sun light, plants will die.  

There are varieties of products that use solar energy.  These products are called as solar devices or solar thermal collectors. The Solar thermal  technology use the solar heat to heat water or air.  Let us see some of the applications of solar energy in various fields

Solar energy applications for houses

There are a lot of advantages of solar energy for homes.  Solar energy is used at home for water heating with solar heaters. The solar panels installed on roof tops of our houses are used to generate electricity from solar energy.  The batteries store energy captured during day time and supply power through out the day.  This helps us to reduce the expenditure on electricity as well as help us to have power during power cuts.
Solar Energy for Industrial applications

The solar energy  can be used in offices, ware houses and industries for supplying power.  The Solar energy can be used to supply electricity for Radio and TV stations.  Solar energy can be used for supplying electricity to light houses and warning lights for aircraft.

Solar energy can also be used for power generation in remote places like schools, homes and other places where there is no electricity available.  The water pumps in remote areas can be run on solar energy.

The solar energy can also be used for public transportation system like buses and light rails and trolleys.


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