Solar energy - For a brighter future.
How can we harvest this energy? There are 2 practical ways to explore solar power: 1- Using photovoltaic cells to transform solar light into electricity. 2- Using water storage systems to heat water using solar heat.
(Photovoltaic cells)
(Solar Heating Kit)
Solar Panels Here’s a simple explanation on how the panels work: The sun light hits each of the panel’s cells and is absorbed by semiconducting materials, such as silicon. Their electrons are then released from the atoms, this allows them to flow through the material and produce electricity. An array of cells converts solar energy into a usable amount of direct current (DC) electricity.
The disadvantages of the photovoltaic cells
Although solar panels are continually being improved, there are still some inconvenients to their use: -At the moment, their prices are still high, although eventually it pays off. - They require a sunny place to be installed and are difficult to remove. - The cells contain a metal called cadmium and it can create a serious environmental injury if handled inappropriately.
Solar heating
Solar heating consists in gathering the sun’s thermal energy and eventually store it in order to heat water or space when it’s needed. There are 2 methods of solar heating: Active solar heating uses pumps which move air or a liquid from the solar collector into the building or storage area. Passive solar heating does not require electrical or mechanical equipment, and may rely on the design and structure of the house to collect, store and distribute heat throughout the building.
Why should we use solar energy? - Solar power is a clean and renewable energy source. - It makes us independent from fossil fuels and their unstable prices. - Solar energy allows us to have electricity in our house even if there’s a blackout.
Solar powered vehicles Solar powered vehicles use photovoltaic cells to produce electricity, as such they mostly rely on the sun’s light in order to run. In the present day, hybrids are a good alternative to fossil fuelled cars. They may not run as fast but they don’t emit greenhouse gases and are cheaper to maintain. In 2006, The Venturi Astrolab produced the world's first commercial electro-solar hybrid car, such vehicles are already available for purchase. Since 1987, there is a biannual solar-powered car race, called World Solar Challenge, where teams compete over 3,021 km across central Australia. The winner’s top average speed was 90.87 km per hour. Japan's biggest shipping line Nippon Yusen KK and Nippon Oil Corporation are working on a solar powered ship by installing a 40 kilowatts solar cell on top of a 1 tonne car carrier ship to be used by Toyota Motor Corporation. Solar powered planes are also real. In 1974, Sunrise II, was the first unmanned solar powered plane to take flight. Later on 29 April 1979, Larry Mauro piloted the Solar Riser, reaching an altitude of 12m. Today’s record for the longest unmanned flight was made by the Zephyr plane, flying for 54-hours straight and at an altitude of 18 km, in September 2007.
(Venturi AstroLab electro-solar hybrid)
(Solar Riser)
Curiosities: Did you know that.... The total solar energy absorbed by the Earth is approximately 3,850,000 exajoules per year? In 2002, this was more energy in one hour than the world used in one year. The solar energy hitting the Earth in just one year is about twice as much as the energy that could ever be obtained from all of the Earth's fossil fuels? Solar bowls are able to focus the light’s beams and can be used to cook meals? The world’s largest solar power plant produces enough electricity to supply approximately 8,000 homes (11 megawatt)? It was finished in January 2007, it occupies a 60-hectare area and it’s located in the Serpa region, Portugal. Due to the energy crisis in the 1970s, the Israeli Knesset passed a law requiring the installation of solar water heaters in all new homes? As a result, Israel is now the world leader in the use of solar energy per capita (3% of the primary national energy consumption).
(Serpa power plant)
(Solar Bowl)
Manuel Teixeira Gomes Secondary School Portim達o - Portugal A web2class presentation by Alexei Buruian, Bernardo, Joana March 2009