31-05-2012, 12:04 PM
SOLAR POWER STATIONS
SOLAR POWER STATIONS.ppt (Size: 1.49 MB / Downloads: 67)
What is Solar Energy?
Originates with the thermonuclear fusion reactions occurring in the sun.
Represents the entire electromagnetic radiation (visible light, infrared, ultraviolet, x-rays, and radio waves).
OPERATION OF THE SOLAR POWER STATION
Solar field comprising rows of trough reflectors for collecting the solar energy from the Sun. These trough collectors, illustrated in Figure, would consist of glass reflectors attached to a structure that, driven by small mechanical drives, allow the collectors to track the Sun
Solar heat would be collected by a solar receiver that runs the length of each trough. Oil, specially designed as a heat carrier is pumped through these pipes;
A central power block where the heat from the solar field would be converted to superheated steam which would power a conventional 22 MW turbo alternator for power generation. The steam generator would be a heat exchanger and have provision for drawing heat from either the solar field or from heat storage;
ENERGY STORAGE, AUXILIARY FUEL AND THE PERFORMANCE OF SOLAR GENERATION
Solar generating plants collect the energy from the Sun for conversion to electricity. To allow generation at times when the Sun is not shining, the captured solar energy must be stored for later use or an alternative source of heat must be available for use. Typically, in the case of solar thermal plants, energy is stored as heat while with PV this requires the use of batteries. There is also research into energy storage in the form of hydrogen or compressed air. Alternative energy sources such as gas can be used at night or when the Sun is obscured by cloud.
Solar photovoltaic (PV) options
Photo voltaic generation technology is commercially proven and large multi-megawatt generation plants have been operating since the 1990s. Costs associated with the technology are high, but the technology is well-known and reliable. The largest plants are based on fixed solar panels inclined at latitude angle.
TYPES OF THE PHOTOVOLTAIC CELL
Fixed flat panel photovoltaic:
A fixed flat panel system has no moving parts and offers the solution with the least ongoing cost of the PV options
Tracking flat panel photovoltaic:
A tracking array can move on one or two axes in order to expose the PV module surface to follow the Sun and capture the greatest amount of solar radiation possible. Compared to a fixed system, a tracking system will provide a greater electrical output per module
Concentrating photovoltaic (CPV):
In order to reduce the net cost of the expensive PV cells, mirrors or lenses can be used to focus energy onto a smaller area of PV material. The reason CPV systems are interesting is that the cost of the collector is generally lower than the same area of solar cells. The catch is that the solar cell needs to be cooled (solar cells operate best when cool). Also, a CPV system is less effective on overcast days because the light striking the concentrator is diffused by the clouds