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The world needs pure, permanent, secure, accessible and free energy for everyone. We actually have the source, it's the sun. Almost every source of energy comes from the sun, petroleum is solar heat confined in plants and animals, wind energy is produced with different temperatures around the Earth, fussions energy is being produced in the Sun every day and every moment.
Arquimides, the greek philosopher, once used the sun to burn out an invasor fleet with help of some mirrors. In France, in the XIX century some experiments took place regarding solar energy. Now a day, since 1970, when the fossil fuels declining situation was shown, the energy from the sun received special attention as a substitute.
Electric Generation The sun is the most powerful energetic source for human kind, we receive 4*1015 kilowatts-hour per day; this means 500,000 times the capacity of a country to produce energy. The energy from the sun can produce electricity in several ways like photovoltaic cells, solar batteries and reflectors. Photovoltaic Cells They transform directly solar energy into electric energy. They achieve an efficiency of 18% the incident radiation. With technological improvements, the maximum efficiency can achieve around 27%. In the other hand fossil fuels efficiency is around 30 to 40 percent and generate pollution. Solar Reflectors One method use solar reflectors to concentrate solar rays. Now a day France is working in big mirrors that generate high temperature (up to 3000C) for industrial use and for the generation of electric current. Termic Solar Collectors One way to confine the solar energy is heating water by passing it through collectors and keeping it in isolated containers. In some areas is possible to obtain enough hot water to satisfy a house needs during day but conventional heaters are required at night.
There are different kinds of solar collectors like black copper pipes or aluminum pipes with a low reflecion cover inside of a vacuum crystal pipe, that can heat water even at low atmospheric temperatures. Radiation can be concentrated to obtain higher temperatures with the help of devises like solar reflectors and magnifying glasses.
It is essential to know weather conditions, location, hours of use in combination with the user's economic resources available. Now a day there are solar ovens that concentrate solar radiation that can generate temperatures of up to 3300 C (like in the Pyrenees), so it is possible to produce great amount of steam and move huge turbines to generate electricity or fuse minerals with a high fuse point.
Solar Heating Solar space heating is divided itno two categories labeled passive and active. Passive Solar Heating A passive system has no mechanical pumps for circulating heat. The method derives thermal energy from solar radiation entering a building through south-facing windows to be absorbed by structures inside the building. This thermal energy is distributed within the building by natural heat-transfer methods of conduction, convection and radiation. Tasks for making the system operational include
For example. A glass window is very effective at letting solar radiation into de building, but the heat loss through the window is about 25 times more than through a well constructed and insolated wall of the same size. Active Solar Heating An active solar heating system converts solar energy to thermal energy in collectors located on the outside of a building and circulated throughout a dwelling with mechanical pumps. Because active solar systems are simple in principle, there are many construction plans available; the variety of factors to be considered include:
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