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energy source. physics. Learn about this topic in these articles: Earth’s interior. In geology: Oil and natural gas. …yet make them attractive alternative energy resources. Read More. materials science. In materials science: Materials for energy. An industrially advanced society uses energy and materials in large amounts.
- Overview
- Thermal energy
Solar energy is the radiation from the Sun capable of producing heat, causing chemical reactions, or generating electricity. The total amount of solar energy received on Earth is vastly more than the world's current and anticipated energy requirements. If suitably harnessed, solar energy has the potential to satisfy all future energy needs.
What are the common uses of solar energy?
Solar energy is commonly used for solar water heaters and house heating. The heat from solar ponds enables the production of chemicals, food, textiles, warm greenhouses, swimming pools, and livestock buildings. Cooking and providing a power source for electronic devices can also be achieved by using solar energy.
How is solar energy collected?
The most common devices used to collect solar energy and convert it to thermal energy are flat-plate collectors. Another method of thermal energy conversion is found in solar ponds, which are bodies of salt water designed to collect and store solar energy. Solar radiation may also be converted directly into electricity by solar cells, or photovoltaic cells, or harnessed to cook food in specially designed solar ovens, which typically concentrate sunlight from over a wide area to a central point.
solar energy, radiation from the Sun capable of producing heat, causing chemical reactions, or generating electricity. The total amount of solar energy incident on Earth is vastly in excess of the world’s current and anticipated energy requirements. If suitably harnessed, this highly diffused source has the potential to satisfy all future energy needs. In the 21st century solar energy is expected to become increasingly attractive as a renewable energy source because of its inexhaustible supply and its nonpolluting character, in stark contrast to the finite fossil fuels coal, petroleum, and natural gas.
Among the most common devices used to capture solar energy and convert it to thermal energy are flat-plate collectors, which are used for solar heating applications. Because the intensity of solar radiation at Earth’s surface is so low, these collectors must be large in area. Even in sunny parts of the world’s temperate regions, for instance, a collector must have a surface area of about 40 square metres (430 square feet) to gather enough energy to serve the energy needs of one person.
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The most widely used flat-plate collectors consist of a blackened metal plate, covered with one or two sheets of glass, that is heated by the sunlight falling on it. This heat is then transferred to air or water, called carrier fluids, that flow past the back of the plate. The heat may be used directly, or it may be transferred to another medium for storage. Flat-plate collectors are commonly used for solar water heaters and house heating. The storage of heat for use at night or on cloudy days is commonly accomplished by using insulated tanks to store the water heated during sunny periods. Such a system can supply a home with hot water drawn from the storage tank, or, with the warmed water flowing through tubes in floors and ceilings, it can provide space heating. Flat-plate collectors typically heat carrier fluids to temperatures ranging from 66 to 93 °C (150 to 200 °F). The efficiency of such collectors (i.e., the proportion of the energy received that they convert into usable energy) ranges from 20 to 80 percent, depending on the design of the collector.
Another method of thermal energy conversion is found in solar ponds, which are bodies of salt water designed to collect and store solar energy. The heat extracted from such ponds enables the production of chemicals, food, textiles, and other industrial products and can also be used to warm greenhouses, swimming pools, and livestock buildings. Solar ponds are sometimes used to produce electricity through the use of the organic Rankine cycle engine, a relatively efficient and economical means of solar energy conversion, which is especially useful in remote locations. Solar ponds are fairly expensive to install and maintain and are generally limited to warm rural areas.
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The total entry for "Energy" in the first edition (1771) of the Encyclopaedia Britannica is as follows: "A term of Greek origin signifying the powers, virtues or efficacy of a thing. Source for information on Scientific and Technical Understanding of Energy: Macmillan Encyclopedia of Energy dictionary.
nuclear energy, energy that is released in significant amounts in processes that affect atomic nuclei, the dense cores of atoms. It is distinct from the energy of other atomic phenomena such as ordinary chemical reactions , which involve only the orbital electrons of atoms.
- The Editors of Encyclopaedia Britannica
By: Hannah Ritchie. February 10, 2020. Cite this article Reuse our work freely. Summary. All energy sources have negative effects, but they differ enormously in size: as we will see, fossil fuels are the dirtiest and most dangerous, while nuclear and modern renewable energy sources are vastly safer and cleaner.
alternative energy, Any of various renewable power sources to use in place of fossil fuels and uranium. Fusion devices ( see nuclear fusion) are believed by some to be the best long-term option, because their primary energy source would be deuterium, abundant in ordinary water.
May 9, 2024 · petroleum, complex mixture of hydrocarbons that occur in Earth in liquid, gaseous, or solid form. A natural resource, petroleum is most often conceived of in its liquid form, commonly called crude oil, but, as a technical term, petroleum also refers to natural gas and the viscous or solid form known as bitumen, which is found in tar sands.
