Solar Energy Devices

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  Solar energy has been around since the 1830s when astronomer John Herschel invented a solar thermal collector box, according to the U.S. Energy Information Administration. In the past decade, however, solar energy has made big strides as more and more people and businesses are becoming environmentally conscious. Five main types of solar devices help to collect energy from the sun.
  
  

Photovoltaic Cells

• Photovoltaic cells convert sunlight into electrical power and can be used to power small items such as watches, but are most often used for large electric grids that provide electricity for cities or regions. According to a description provided by the U.S. Energy Information Administration, "PV cells are made of semiconductors, such as crystalline silicon or various thin-film materials."
  
  

Solar Thermal Power Plants

• According to the U.S. Energy Information Administration, "Solar thermal power plants use the sun's rays to heat a fluid to very high temperatures. The fluid is then circulated through pipes so it can transfer its heat to water to produce steam. The steam, in turn, is converted into mechanical energy in a turbine and into electricity by a conventional generator coupled to the turbine." There are three types of solar thermal power plants: solar dishes, parabolic troughs and solar power towers. The U.S. Energy Information Administration reports that solar dishes are large dish-shaped objects that point toward the sun and use solar collectors to gather energy. Parabolic troughs use parabolic-shaped reflectors to target the sun's rays. Solar power towers are towers that absorb heat from the sun.
  
  

Solar Thermal Collectors

• Solar thermal collectors are usually flat panels or transparent coverings that absorb the sun and thus absorb heat, according to the U.S. Energy Information Administration. Solar thermal collectors are often used on the roofs of homes in the form of panels and on swimming pools in the form of a transparent cover. In some cases, on houses, fans or pumps are used to circulate the heat.
  
  

Solar Balloons

• Solar balloons are in the very early stages of existence as of November 2010, but according to Inhabitant.com can offer more economical photovoltaic arrays. Inhabitant.com describes solar balloons as essentially "helium filled platforms constructed from a new fabric coated with photovoltaic solar cells." The balloons are made up of a control panel, a helium supply cable and a power cable and may eventually be available to heat homes and buildings.
  
  

Solar Water Heaters

• Solar water heaters are used to heat water and consist of insulated storage tanks and solar collectors. In a direct circulation system, a collector attracts heat and according to the U.S. Department of Energy, "pumps circulate household water through the collectors and into the home." These heaters work best in warmer climates. For people living in colder climates, a solar water heater with an indirect circulation system may work better. In describing these water heaters, the U.S. Department of Energy states that "Pumps circulate a non-freezing, heat-transfer fluid through the collectors and a heat exchanger. This heats the water that then flows into the home."