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A combined cycle is characteristic of a power producing engine or plant that employs more than one thermodynamic cycle. Heat engines are only able to use a portion of the energy their fuel generates (usually less than 50%). The remaining heat (e.g. hot exhaust fumes) from combustion is generally wasted. Combining two or more "cycles" such as the Brayton cycle and Rankine cycle results in improved overall efficiency. It can also work with the Otto, diesel, and Crower cycles which may allow it to be suited to automotive use. Aside from the Rankine cycle, the Stirling cycle could also be used to re-use waste heat in automotive or aeronautical applications, for the simple reason that there is less weight (water) to carry and that stirling engines or turbines can be made to operate with low temperature differences.

In a combined cycle power plant (CCPP), or combined cycle gas turbine (CCGT) plant, a gas turbine generator generates electricity and the waste heat is used to make steam to generate additional electricity via a steam turbine; this last step enhances the efficiency of electricity generation. Most new gas power plants in North America and Europe are of this type. In a thermal power plant, high-temperature heat as input to the power plant, usually from burning of fuel, is converted to electricity as one of the outputs and low-temperature heat as another output. As a rule, in order to achieve high efficiency, the temperature difference between the input and output heat levels should be as high as possible (see Carnot efficiency). This is achieved by combining the Rankine (steam) and Brayton (gas) thermodynamic cycles. Such an arrangement used for marine propulsion is called Combined Gas (turbine) And Steam (turbine) (COGAS).

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The advantages of combined cycle gas turbines are high power-to-weight ratio, smaller, fewer moving parts and less vibration than a reciprocating engine. Other advantages include very low toxic emissions, runs on a wide variety of fuels, and high operating speeds. Disadvantages are higher cost, longer start-up, less responsive to power demands, and a shrill whining noise.

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Q: What are the Advantages and disadvantages of a Combined Cycle Gas Turbines?
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What are some examples of a stationary combustion turbine?

Industrial gas turbines differ from aeroderivatave in that the frames, bearings, and blading is of heavier construction. Industrial gas turbines range in size from truck-mounted mobile plants to enormous, complex systems. They can be particularly efficient--up to 60%--when waste heat from the gas turbine is recovered by a heat recovery steam generator to power a conventional steam turbine in a combined cycle configuration. They can also be run in a cogeneration configuration: the exhaust is used for space or water heating, or drives an absorption chiller for cooling or refrigeration. A cogeneration configuration can be over 90% efficient. The power turbines in the largest industrial gas turbines operate at 3,000 or 3,600 rpm to match the AC power grid frequency and to avoid the need for a reduction gearbox. Such engines require a dedicated enclosure, both to protect the engine from the elements and the operators from the noise. Simple cycle gas turbines in the power industry require smaller capital investment than either coal or nuclear power plants and can be scaled to generate small or large amounts of power. Also, the actual construction process can take as little as several weeks to a few months, compared to years for base load power plants. Their other main advantage is the ability to be turned on and off within minutes, supplying power during peak demand. Because they are less efficient than combined cycle plants, they are usually used as peaking power plants, which operate anywhere from several hours per day to a couple dozen hours per year, depending on the electricity demand and the generating capacity of the region. In areas with a shortage of base load and load following power plant capacity, a gas turbine power plant may regularly operate during most hours of the day and even into the evening. A typical large simple cycle gas turbine may produce 100 to 300 megawatts of power and have 35-40% thermal efficiency. The most efficient turbines have reached 46% efficiency.[2]


Which of the following can be called non-conventional source of energy?

The non-conventional sources of energy are: 1. Wind Energy advantages- non-polluting; low cost production of electricity once setup; safe and clean disadvantages- noise pollution; wind mills costly to setup; disturbs radio and T.V. reception; harmful to birds. 2. Solar Energy advantages- inexhaustible; non-polluting disadvantages- expensive; diffused source, so gets wasted. 3. Tidal Energy advantages- non-polluting; inexhaustible disadvantages- destroys wildlife habitat; difficult to harness 4. Nuclear energy advantages- Emits large amount of energy disadvantages- generates radioactive waste; expensive 5. Bio Gas advantages- low cost; easy to operate; makes use of bio waste disadvantages- causes green house effect 6. Geothermal Energy advantages- clean Eco friendly and always available disadvantages- located far away from cities and so costly to transport the electricity


How is water is used in nuclear power generation?

Water is used to transfer heat from the nuclear fuel in the reactor to the steam generators where it transfers heat to the secondary water to make steam. The steam is then used to turn turbines. Water from an external source is also used to condense the steam from the turbine exhaust, and this water is then returned to the steam generators to continue the cycle.


What is hydro cycle?

Water cycle is often referred as hydro-logic cycle. It is a cyclic process.


Which object has a periodic motion?

a boncing ball or any cycle(water cycle moon cycle etc)

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How is recent combination cycle gas turbines lost?

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