Mankind has been harnessing the energy of the sun since the seventh century B.C. The sun’s rays shower the earth’s surface and humans have been using them to satisfy their energy needs. Each hour of sunshine theoretically will contribute to satisfy the globe’s energy demand per annum. The ancient civilizations particularly, Rome and Greece demonstrated their initial documented use of sunlight by burning mirrors to light torches for spiritual functions. Ancient architectural designs in Rome and Greece utilized passive solar design i.e. the utilization of sunlight to heat and light indoor areas. This system still remains until today as one of the foremost economical in which to use the alternative energy. This was taken a step additionally and mica was used to cover south facing buildings to trap the warmth.
A jump in time to the Ninetieth century shows great advancements in technology and different needs to tap sunlight to useful work. The history of alternative solar energy hence, demonstrates advancements in solar technologies comparing to changes in human energy demand. With environmental conditions and depletion, and cost of fossil fuels, today’s world perpetually strives for the most effective technically and economically feasible way to use definitely the greatest natural resource – the sun.
In 1839 French scientist Edmond Becquerel astonishingly at the age of nineteen years discovers the photovoltaic effect while experimenting with an electrolytic cell made up of two metal electrodes (Platinum) placed in an electricity-conducting solution where electricity-generation increased once exposed to Direct Sun light. Also he discovered different colours and different types of light had produced different effects on producing power. Best results he obtained from Blue lights and Ultra violet coloured lights. Even he tested with Coating of various materials over the electrode. He obtained Silver Chloride AgCl or Silver Bromide AgBr coating produces maximum efficiency.
In 1860s French mathematician August Mouchet proposed an idea for solar-powered steam engines. In that project, solar energy could be used to power engines to do tasks such as Ice making. He coupled steam engine to his refrigeration device where steam engine power got from sun. In the following 20 years, he and his assistant, Abel Pifre, designed the first solar powered engines and used them for a variety of applications. These engines became the forerunner of modern parabolic dish collectors.
In 1873 Willoughby Smith an electrical engineer of UK and his assistant Joseph May discovered the photoconductivity of selenium (Se). The electrical resistance properties varied (decreased) dramatically with the amount of light (increase intensity of incident light) falling on it. This concept is used for converting images into electrical signals, which is the basis for yesteryears television system. He also tested the conductivity properties of Selenium, which is exposed to light.
In 1877 William Grylls Adams and his student Richard Evans Day of UK discovered that selenium produces electricity once exposed to light. In spite of selenium solar cells failed in their attempt to convert enough sunlight to power (1 to 2 percentage efficiency) the electrical equipment, they verified that a solid material may change the light into electricity without heat or moving elements. Until 1970, Selenium cell properties used for very low power applications such as photographic exposure meter.