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Active Solar Energy Systems
direct use of solar energy that requires mechanical power; usually consists of pumps and other machinery to circulate air, water, or other fluids from solar collectors to a heat sink where the heat may be stored
renewable and nonrenewable energy resources that are alternatives to fossil fuels
device that produces electricity directly from a chemical reaction in a specially designed cell; in the simplest case the cell uses hydrogen as a fuel, to which an oxidant is supplied. The hydrogen is combined with oxygen as if the hydrogen were burned, but the reactants are separated by an electrolyte solution that facilitates the migration of ions and the release of electrons (which may be tapped as electricity)
energy sources, including nuclear and geothermal, that are dependent on fuels, or on a resource that may be used up much faster than it is replenished by natural process
Passive Solar Energy Systems
direct user of solar energy through architectural design to enhance or take advantage of natural changes in solar energy that occur throughout the year without requiring mechanical power
technology that converts sunlight directly into electricity using a solid semiconductor material
alternative energy sources, such as solar, water, wind, and biomass, that are more or less continuously available in a time framework useful to people
a device for collecting and storing solar energy; home water heating is done by flat panels consisting of a glass cover plate over a black background on which water is circulated through tubes. Short-wave solar radiation enters the glass and is absorbed by the black background. As long-wave radiation is emitted from the black material, it cannot escape through the glass, so the water in the circulating tube is heated, typically to temperatures of 38 to 93 degrees
energy generated by ocean tides in places where favorable topography allows for construction of a power plant
alternative energy source derived from flowing water; one of the world's oldest and most common energy sources; sources vary in size from microhydropower systems to large reservoirs and dams
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