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 The Solar Car Book A complete kit for making a cool solar racecar. Everything is included: wheels, axles, motors, wires and a genuine one-volt solar cell. |
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Solar Energy See also:
Solar energy is energy from the Sun in the form of radiated heat and light. It drives the climate and weather and supports life on Earth. Solar energy technologies make controlled use of this energy resource. Solar power is a synonym of solar energy and/or refers specifically to the conversion of sunlight into electricity by photovoltaics, concentrating solar thermal devices or various experimental technologies. In building design, thermal mass is used to conserve heat, and daylighting techniques optimize light. Solar water heaters heat swimming pools and provide domestic hot water. In agriculture, greenhouses grow specialty crops and photovoltaic-powered pumps bring water to grazing animals. Evaporation ponds find applications in the commercial and industrial sectors where they are used to harvest salt and clean waste streams of contaminants. Solar distillation and disinfection techniques produce potable water for millions of people worldwide. Family scale solar cookers and larger solar kitchens concentrate sunlight for cooking, drying and pasteurization. More sophisticated concentrating technologies magnify the rays of the Sun for high temperature material testing, metal smelting, and industrial chemical production. A range of prototype solar vehicles provide ground, air and sea transportation. Energy from the SunEarth continuously receives 174 PW of incoming solar radiation (insolation) at the upper atmosphere.[2] When it meets the atmosphere, 6% of the insolation is reflected and 16% is absorbed.[2] Average atmospheric conditions (clouds, dust, pollutants) further reduce insolation traveling through the atmosphere by 20% due to reflection and 3% via absorption.[2] These atmospheric conditions not only reduce the quantity of energy reaching the earth's surface, but also diffuse approximately 20% of the incoming light and filter portions of its spectrum.[3] After passing through the atmosphere, approximately half the insolation is in the visible electromagnetic spectrum with the other half mostly in the infrared spectrum (a small part is ultraviolet radiation).[4] The absorption of solar energy by atmospheric convection (sensible heat transport) and evaporation and condensation of water vapor (latent heat transport) powers the water cycle and drives the winds.[5] Sunlight absorbed by the oceans and land masses keeps the surface at an average temperature of 14 °C.[6] The conversion of solar energy into chemical energy via photosynthesis produces food, wood and the biomass from which fossil fuels are derived.[7] Solar radiation along with secondary solar resources such as wind and wave power, hydroelectricity and biomass, account for over 99.9% of the available flow of renewable energy on Earth.[8][9] The flows and stores of solar energy in the environment are vast in comparison to human energy needs.
The output of a solar panels will vary according to their conversion efficiency and the amount sunlight the received. For example, in the United States and Europe, the average insolation at ground level over an entire year (including nights and periods of cloudy weather) is 7.5 to 21.5 MJ/m²/day (2.09 to 5.96 kWh/m²/day).[15][16] At present, photovoltaic panels typically convert about 15% of incident sunlight into electricity; therefore, a solar panel, may on average, deliver 1.12 to 3.22 MJ/m²/day (0.31 to 0.90 kWh/m²/day).[17] By contrast, typical solar water heating systems operating at 60% efficiency will deliver 4.5 to 12.9 MJ/m²/day.[18] See also Insolation & solar radiation Types of technologiesSolar energy technologies utilize solar radiation for practical ends. Technologies that utilize secondary solar resources such as biomass, wind, waves, and ocean thermal gradients can be included in a broader description of solar energy but only primary resource applications are discussed here. The qualities and performance of solar technologies vary widely between regions; therefore, solar technologies should be deployed in a way that carefully considers these variations. Solar technologies such as photovoltaics and water heaters increase the supply of energy and may be characterized as supply side technologies. Technologies such as passive design and shading devices reduce the need for alternate resources and may be characterized as demand side. Optimizing the performance of solar technologies is often a matter of controlling the resource rather than simply maximizing its collection. For more information see the following links:
Notes
This article is licensed under the GNU Free Documentation License. It uses material from Wikipedia Encyclopedia article "Solar Energy" |
