12-11-2012, 06:05 PM
Solar power
SOLAR POWER.ppt (Size: 619 KB / Downloads: 48)
Introduction
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.
Energy from the Sun
Map of global solar energy resources. The colors show the average available solar energy on the surface during 1991 to 1993. The scale is in Watts per square meter. For comparison, the dark disks represent the land area required to supply the primary energy demand in the year 2010, using currently available technology.
The second map shows the average global irradiance calculated from satellite data collected from 1991 to 1993.
Solar heating systems
ThSolar hot water systems use sunlight to heat water.ey may be used to heat domestic hot water or for space heating.
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.
Solar lighting
Solar lighting or daylighting is the use of natural light to provide illumination.
Daylighting features include building orientation, window orientation, exterior shading, sawtooth roofs, clerestory windows, light shelves, skylights and light tubes are others.
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]
Photovoltaics
Solar 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.