How do we get solar energy?
Question:
Answer:
It's radiated by the sun and travels to earth.
We can collect solar energy via electronics that convert the light directly to electricity or by heating something like water and using the water to perform work that produces electricity.
We get solar energy when we eat sugar or starch.
Solar power is the technology of obtaining usable energy from the light of the Sun. Solar energy has been used in many traditional technologies for centuries and has come into widespread use where other power supplies are absent, such as in remote locations and in space.
Solar energy is currently used in a number of applications:
Heating (hot water, building heat, cooking)
Electricity generation (photovoltaics, heat engines)
Desalination of seawater.
Its application is spreading as the environmental costs and limited supply of other power sources such as fossil fuels are realized.
ENERGY FROM SUN:
Solar radiation reaches the Earth's upper atmosphere at a rate of 1,366 watts per square meter (W/m2).[1] While traveling through the atmosphere, 6% of the incoming solar radiation (insolation) is reflected and 16% is absorbed resulting in a peak irradiance at the equator of 1,020 W/m².[2] Average atmospheric conditions (clouds, dust, pollution) reduce insolation by 20% through reflection and 16% through absorption.[3] In addition to affecting the quantity of insolation reaching the surface, atmospheric conditions also affect the quality of insolation reaching the surface by diffusing incoming light and altering its spectrum.
The image on the right shows the average global irradiance calculated from satellite data collected from 1991 to 1993. For example, in North America the average insolation lies between 125 and 375 W/m² (3 to 9 kWh/m²/day). [4] This is the available power, and not the delivered power. Photovoltaic panels currently convert about 15% of incident sunlight into electricity; therefore, a solar panel in the contiguous United States on average delivers 19 to 56 W/m² or 0.45-1.35 kWh/m²/day. [5] The dark disks on the second image on the right are an example of the land areas that, if covered with 8% efficient solar panels, would produce slightly more energy in the form of electricity than the total primary energy supply in 2003. [6] While average insolation and power values offer insight into solar power's potential on a regional scale, locally relevant conditions need to be assessed to determine the solar potential of a specific site.
A recent concern is global dimming, an effect of pollution that is allowing less sunlight to reach the Earth's surface. It is intricately linked with pollution particles and global warming, and it is mostly of concern for issues of global climate change, but is also of concern to proponents of solar power because of the existing and potential future decreases in available solar energy. The order of magnitude is about 4% less solar energy available at sea level over the timeframe 1961–90, mostly from increased reflection from clouds back into outer space. [7]
After passing through the Earth's atmosphere, most of the sun's energy is in the form of visible and Infrared radiations. Plants use solar energy to create chemical energy through photosynthesis. Humans regularly use this energy burning wood or fossil fuels, or when simply eating the plants.
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Types of technologies
Many technologies have been developed to make use of solar radiation. Some of these technologies make direct use of the solar energy (e.g. to provide light, heat, etc.), while other technologies produce electricity.
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Solar design in architecture
Main articles: Passive solar and Active solar
Solar design can be used to achieve comfortable temperature and light levels with little or no additional energy. This can be through passive solar, which maximises the entrance of sunlight in very cold conditions and reduces it in hot weather; and active solar, which uses additional devices such as pumps and fans to direct warm and cool air or fluid.
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Solar heating systems
Main article: Solar hot water
Solar hot water systems use sunlight to heat water. These systems may be used to heat domestic hot water or for space heating. These systems are basically composed of solar thermal collectors and a storage tank.[8] The three basic classifications of solar water heaters are:
Active systems which use pumps to circulate water or a heat transfer fluid.
Passive systems which circulate water or a heat transfer fluid by natural circulation. These are also called thermosiphon systems.
Batch systems using a tank directly heated by sunlight.
A Trombe wall is a passive solar heating and ventilation system consisting of an air channel sandwiched between glazed windows and a sun-facing wall. Sunlight heats the thermal mass during the day and drives natural circulation through vents at the top and bottom of the wall. During the evening the trombe wall radiates stored heat.[9]
A transpired collector is an active solar heating and ventilation system consisting of a perforated sun-facing wall which acts as a solar thermal collector. The collector pre-heats air as it is drawn into the building's ventilation system through the perforations. These systems are inexpensive and commercial models have achieved efficiencies above 70 percent. [10]
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Solar cooking
Main article: Solar cooker
Solar Cookers use sunshine as an alternative to fire for cooking.A solar box cooker traps the Sun's energy in an insulated box; such boxes have been successfully used for cooking, pasteurization and fruit canning. Solar cooking is helping many developing countries, both reducing the demands for local firewood and maintaining a cleaner environment for the cooks. The first known western solar oven is attributed to Horace de Saussure in 1767, which impressed Sir John Herschel enough to build one for cooking meals on his astronomical expedition to the Cape of Good Hope in Africa in 1830. [11] Today, there are many different designs in use around the world. [12]
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Solar lighting
Main articles: Daylighting and Light tube
Solar lighting or daylighting is the use of natural light to provide illumination. Daylighting offsets energy use in electric lighting systems and reduces the cooling load on HVAC systems. Although difficult to quantify, the use of natural light also offers physiological and psychological benifits. Builiding orientation, exterior shading, sawtooth roofs, clerestory windows, light shelves, skylights and light tubes are among the many daylighting features.[13] These features may be incorporated in existing structures but are most effective when integrated in a solar design package which accounts for factors such as glare, heat gain, heat loss and time-of-use. Achitectural trends increasingly favor daylighting as a cornerstone of sustainable design.
Daylight saving time (DST) can be seen as a method of utilising solar energy by matching available sunlight to the hours of the day in which it is most useful. DST energy savings have been estimated to reduce total electricity use in California by .5% (3400 MWh) and peak electricity use by 3% (1000 MW).[14]
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Photovoltaics
Main article: Photovoltaics
The solar panels (photovoltaic arrays) on this small yacht at sea can charge the 12 V batteries at up to 9 A in full, direct sunlightSolar cells, also referred to as photovoltaic cells, are devices or banks of devices that use the photovoltaic effect of semiconductors to generate electricity directly from sunlight. Until recently, their use has been limited because of high manufacturing costs. One cost effective use has been in very low-power devices such as calculators with LCDs. Another use has been in remote applications such as roadside emergency telephones, remote sensing, cathodic protection of pipe lines, and limited "off grid" home power applications. A third use has been in powering orbiting satellites and other spacecraft.
Total peak power of installed PV is around 5,300 MW as of the end of 2005.[citation needed] This is only one part of solar-generated electric power. For solar reflector plants see below.
Declining manufacturing costs (dropping at 3 to 5% a year in recent years) are expanding the range of cost-effective uses. The average lowest retail cost of a large photovoltaic array declined from $7.50 to $4 per watt between 1990 and 2005[citation needed]. With many jurisdictions now giving tax and rebate incentives, solar electric power can now pay for itself in five to ten years in many places. "Grid-connected" systems - that is, systems with no battery that connect to the utility grid through a special inverter - now make up the largest part of the market. In 2003 worldwide production of solar cells increased by 32%.[15] Between 2000 and 2004 the increase in worldwide solar energy capacity was an annual 60%.[16] 2005 was expected to see large growth again, but shortages of refined silicon have been hampering production worldwide since late 2004.[17] Analysts have predicted the similar supply problems during 2006 and 2007.[18]
Solar thermal electric power plants Image:Solar Two 2003.jpg|right|thumb|200px|Sol... Two, a concentrating solar power tower (an example of solar thermal energy applied to electrical power production).]]
Main article: Solar thermal energy
Solar thermal energy can be used to heat a heat exchanger to high temperature and the heat used to produce electric power or for other industrial purposes.
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Power towers
Main article: Solar power tower
Power towers (also know as 'central tower' power plants or 'heliostat' power plants (power towers)) use an array of flat, moveable mirrors (called heliostats) to focus the sun's rays upon a collector tower (the target). The high energy at this point of concentrated sunlight is transferred to a substance that can store the heat for later use.
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Concentrating collector with steam engine
Solar energy converted to heat in a concentrating collector can be used to boil water into steam (as is done in nuclear and coal power plants) to drive a steam engine or steam turbine. The concentrating collector can be an trough collector, parabolic collector, or power tower
From Mars.
Solar power is the technology of obtaining usable energy from the light of the Sun. Solar energy has been used in many traditional technologies for centuries and has come into widespread use where other power supplies are absent, such as in remote locations and in space.
Solar energy is currently used in a number of applications:
Heating (hot water, building heat, cooking)
Electricity generation (photovoltaics, heat engines)
Desalination of seawater.
Its application is spreading as the environmental costs and limited supply of other power sources such as fossil fuels are realized.
We get solar Enery from the infra-red radiation emiited by sun.
Very minute amount of Infra-Red radiation reach to us & 99% of it get reflected back to Space.
Human Body recive it in form of Vitamin-D.
Through the photo electric cell.
A wonderful invention.
....... in brief ... through light ...... sun light ..
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