30 Sep 2011
A History of Solar Thermal Energy
Throughout humankind’s history, there is one great constant: the sun. Without its power, the world would not have warmth, light or plants. Humans have reaped the benefits of solar energy for centuries and have developed more sophisticated methods of harnessing its power.
Great societies in antiquity have long recognized the path of the sun and its potential within architecture. The Greeks and the Chinese faced their buildings towards the south so that they could naturally harvest the sun’s heat and light during the winter. This was deemed to be a crucial part of the sophisticated knowledge of a culture. Aeschylus, and ancient Greek philosopher, said “Only primitives and barbarians lack knowledge of houses turned to face the Winter sun”. This knowledge was mostly lost in during the Middle Ages in Europe, however in China these techniques continued to flourish. Modern passive solar design incorporates elements such as movable shades, thermal masses for heat storage, special glazes and insulation. Contractors and builders have made entire businesses based on providing energy efficient homes incorporating passive solar design.
Solar energy can also be used actively as well. One of the first documented active uses of solar power is to light torches for various religious ceremonies. The Greeks, the Romans and the Chinese have all been noted to use solar power for this purpose. Until the 18th century however, the use of active solar power is relatively slow. In this period, there was much interest among inventors within the field of concentrated solar power. English scientist Joseph Priestley and French chemist Lavoisier used concentrated solar power to test and develop the theory of combustion. They used large focusing lenses and concentrated the sun’s rays on mercuric oxide and combusted the gas that was produced.
A century later, scientists and engineers began developing solar concentrators. The World’s Fair in Paris, 1878, held one exhibitor who had developed a parabolic reflector and steam boiler combination to power a printing press. In the early 1900s, there were a few experiments with concentrated solar power fueling irrigation pumps. However, as oil and natural gas came into vogue, interest in this variety of solar energy fell.
Today, Solartron Energy Systems is producing an advanced solar concentrating system for a variety of uses. Its parabolic dish tracks the sun on two axes thus constantly operating at peak efficiency. This system is the future of solar thermal energy. It can be used for water heating, process heat, solar cooling and forced air heat. Now there is a surge in interest in solar thermal systems and other clean energy technologies and Solartron Energy Systems is poised to lead the way.