Solar Energy: The Ultimate Renewable Energy Resource Essay

2753 Words 12 Pages
The current use of fossil fuels as our main energy source has two drawbacks: their inevitable depletion and the pollution associated with combustion. These two drawbacks in addition to the growing concern of global warming has pushed for the development of more sustainable sources of energy, namely solar energy and its derivatives (i.e. wind power). Solar energy is appealing for its potential to meet all our demands, while proving to be a pollution free resource.(Bohn, 2009)

Solar energy originates from the thermonuclear fusion reactions occurring in the sun. Leaving all the byproducts of the reactions behind in the sun, the energy that reaches the Earth is pure radiant energy. This energy represents the entire electromagnetic
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The clouds absorb 10% off the energy, while reflecting about 25%, and allow about 17% to pass through. The atmosphere absorbs 9%, reflects 9%, and transmits 6% of the solar energy. Twenty-four percent of the solar energy directly reaches the ground. Overall, about 47% (17+6+24) of the sun’s energy striking the Earth reaches the ground, where it is collectable by solar devices. These devices are used generally for two purposes: to heat water and/or living spaces and to produce electricity.

Solar energy is used to heat water for homes and buildings. Two methods used to accomplish this are the passive system, which has no moving parts and strictly relies on the convection currents, and an active system which uses pumps to move the liquid. In both systems, a solar device called a flat bed collector absorbs the sun’s energy to heat the water. The collector consists of a thin, broad box with a glass or clear plastic top and a black bottom with water tubes embedded in it. The black bottom allows for the maximum amount of heat absorption while the clear cover and interior insulation prevent heat loss. As water is heated in the pipes it rises up to a storage tank where it can then be sent throughout the house for consumption. Cooler water moves into the pipes and forms a convection cycle or current. In the active system, antifreeze is used as the fluid instead of water so it remains a liquid if the outside temperature drops below freezing. Also, a heat