MODERN LESSONS FROM ANCIENT TIMES
October 10th, 2009 at 11:46am Under General
The earliest known uses of solar energy date from way back in the 7th Century BC.
The ancient Egyptians used the sun’s heat to bake straw and mud into bricks which they used as building blocks.Ancient Greeks and Romans recognised the benefits of what we now call passive solar design – using architecture to maximise the sun’s capacity to heat and light indoor spaces.
In order to get the maximum benefit from the winter sun, they made sure their buildings were orientated towards the sun.At the same time, they were able to cut down on firewood which was scarce, displaying a very early switch from fossil fuels to renewable energy.The Romans took solar design a step further by covering south-facing building openings with glass or mica to prevent the heat of the winter sun from escaping, and even made a law against obscuring a neighbour’s access to sunlight.
An active application of solar energy was used as far back as 200BC when the Greek army used the sun’s rays onto bronze shields to set fire to the Roman’s wooden ships.By building their houses into the sides of rocky cliffs, some native American cultures were able to get the most out of the heat trapped by the rocks during the day.
The world’s first solar collector is said to have been built in 1767 by the Swiss Horace de Saussure, but it was only in 1839 when Frenchman Edmond Becquerel first showed photovoltaic activity that the foundation for modern solar power research was set. He discovered that electric current in certain materials could be increased when exposed to light.
The French continued experimentation with solar power, with mathematician Auguste Mouchout inventing the first active solar motor as well as a steam engine powered entirely by the sun.High production costs caused both inventions to fail.
Around the globe, scientists were experimenting with solar energy.In 1876, William Grylls Adams discovered that by exposing selenium to light, it produced electricity without any need for moving parts or heat.
Although Albert Einstein is more widely known for his Theory of Relativity, it was his theories on the photoelectric effect that won him the 1921 Nobel Prize in Physics.
In the 1950s, Bell Laboratories (now known as AT & T Laboratories) developed the first silicon solar cell which could generate a measurable electric current.It was the first time that something had been developed that could convert sufficient amounts of the sun’s energy to power ordinary electrical appliances.
The launch of the satellite, Vanguard 1 in the fifties marked the first practical application of photovoltaic solar cells.The first solar powered aircraft flew across the channel from France to England in 1981 under power from its sixteen thousand solar cells which gave off 3 000W of power.
The Arab Oil Embargo in 1973/4 forced western economies to rethink solar energy research as a means of reducing their dependence on oil. The development of a cost-effective solar cell by Dr Elliot Berman in the 1970s was a major breakthrough, opening up a range of applications such as navigation warning lights as well as uses in remote locations.
Environmental issues, particularly climate change, have been at the heart of the drive to find viable renewable energy sources such as geothermal, wind, wave and solar power.And whilst solar technology today is powering far more than a hand-held radio, the basic idea of solar power has remained the same since ancient times – it is a viable renewable energy source.
By writer Add comment