Solar Energy

In our galaxy, sun is a medium size star. The sun is a glowing fire ball consisting of hot gaseous matter, notably hydrogen and helium. The sun radiates 53 million watts of energy per square meter of its surface. The sun converts 660 million tones of mass into energy every second. Our earth receives 170*1012 Kilowatts (or 170,000 million megawatts) from the sun. The vast amount of energy received by the earth from the sun is 15000 to 20000 times the world’s present total consumption of energy. Solar energy forms the basis for all life on the earth. A variety of technologies are available today to convert sun-light into usable forms of energy. All the solar radiation emitted in the earth’s direction, however, does not reach the surface of the earth. Absorption and scattering processes in the earth’s atmosphere reduce the solar radiation reaching the earth’s surface. The spectral distribution of solar radiation on the earth is greatly influenced by location, climate and atmospheric conditions. The sum of direct, diffuse and ground reflected radiation arriving at the surface is called global or total solar radiation on horizontal surface.

Urban air population by dust, aerosols and presence of water vapour, clouds, ozone, etc. limit the solar radiation at different locations on the earth. Air pollution reduces the direct solar radiation on the earth’s surface due to scattering and absorption when compared with global radiation. Accurate information is necessary for designing solar energy systems. Basing on the radiations available in different parts, the country is divided into five zones. The global radiation ranges from 3.5 to 6.3 KWh per day per square meter. More than 80% of the country receives average solar energy above 5.2 kWh per square meter on the horizontal surface.

There are various kinds of solar products are made available by different companies like solar cooker, solar water heater, solar home lighting, solar lantern, and solar street light