Friday, April 24, 2009
Wednesday, February 25, 2009
Cogeneration and energy storage
Cogeneration is a method for improving efficiency of power plants. It is also gives an idea about the industrial utilization of energy. Usually in a power plant, one or more types of prime movers exist which suitably adjust and allows a fine heat control. Gas turbine is an example. The gas and steam turbine drive separate electrical generators to give some extra added power. Coal-fired boilers are used for the generation of larger power. Here combined-cycle output is increased. In latest systems, coal gasification plant is added.
Acid rain
Sulphuric acid and nitric acid which are formed in atmosphere when sulphur dioxide, nitrogen monoxide and nitrogen dioxide combine with water or hydrogen. Geothermal steam contains stinking H2S and is responsible for the production of a potential source of acid pollution in the atmosphere. Due to acid rain destruction of agricultural crops, forest, and animal life occurs. Naturally generated acid can affect an entire region and can lead to international tension. This is called an ‘acid war’. This is more severe when smelters and power stations are located closed to international boundaries.
Thermo electric energy
Thermoelectric energy is nothing but electrical energy generated from heat. Thermionic conduction in electronic devices is an example. Here the so called thermionic valve is acting as power generator. The output power is too low so this is not an advisable energy tool. When two dissimilar metals are joined and form two junctions with one junction heated, potential difference is developed between the two junctions which is termed as Seebeck effect. Nowadays thermo electric generators with powers 50 KW present. This is very much of use in space applications
High speed turbo alternators
An alternating current generator is known as alternator. Here this device generates a pure intrinsic sine wave of output voltage at power frequency 50 Hertz or 60 Hertz. When a conductor is allowed to move past two well defined magnetic poles on the alternator, the voltage goes through one cycle. So naturally conductor prefer 100 or 200 pole pitches. This pitch or speed is known as the synchronous speed for the given number of poles.
