A closed-cycle gas turbine is a turbine that uses a gas (e.g. air, nitrogen, helium, argon, etc.) for the

working fluid For fluid power, a working fluid is a gas or liquid that primarily transfers force, motion, or mechanical energy. In hydraulics, water or hydraulic fluid transfers force between hydraulic components such as hydraulic pumps, hydraulic cylinders, a ...

as part of a closed thermodynamic system. Heat is supplied from an external source. Note: front matter (including preface and introduction
PDF link
is

open access Open access (OA) is a set of principles and a range of practices through which research outputs are distributed online, free of access charges or other barriers. With open access strictly defined (according to the 2001 definition), or libre op ...

. Such recirculating turbines follow the Brayton cycle.

Background

The initial patent for a closed-cycle gas turbine (CCGT) was issued in 1935 and they were first used commercially in 1939. Seven CCGT units were built in

Switzerland ). Swiss law does not designate a ''capital'' as such, but the federal parliament and government are installed in Bern, while other federal institutions, such as the federal courts, are in other cities (Bellinzona, Lausanne, Luzern, Neuchâtel ...

and Germany by 1978. Historically, CCGTs found most use as external combustion engines "with fuels such as

bituminous coal Bituminous coal, or black coal, is a type of coal containing a tar-like substance called bitumen or asphalt. Its coloration can be black or sometimes dark brown; often there are well-defined bands of bright and dull material within the seams. It ...

, brown coal and blast furnace gas" but were superseded by open cycle gas turbines using cleaner-burning fuels (e.g. " gas or light oil"), especially in highly efficient

combined cycle A combined cycle power plant is an assembly of heat engines that work in tandem from the same source of heat, converting it into mechanical energy. On land, when used to make electricity the most common type is called a combined cycle gas turb ...

systems. Air-based CCGT systems have demonstrated very high availability and reliability. The most notable helium-based system thus far was ''Oberhausen 2'', a 50 megawatt cogeneration plant that operated from 1975 to 1987 in Germany. Compared to Europe where the technology was originally developed, CCGT is not well known in the US.

Nuclear power

Gas-cooled reactors powering helium-based closed-cycle gas turbines were suggested in 1945. The experimental

ML-1 ML-1 was an experimental nuclear reactor built as part of the US Army Nuclear Power Program between 1961 and 1965. It was intended to provide truck-mounted nuclear power that could accompany troops from place to place and provide power to comma ...

nuclear reactor in the early-1960s used a nitrogen-based CCGT operating at 0.9 MPa. The cancelled pebble bed modular reactor was intended to be coupled with a helium CCGT. Future nuclear ( Generation IV reactors) may employ CCGT for power generation, e.g. Flibe Energy intends to produce a liquid fluoride thorium reactor coupled with a CCGT.

Development

Closed-cycle gas turbines hold promise for use with future high temperature solar power and fusion power generation. They have also been proposed as a technology for use in long-term

space exploration Space exploration is the use of astronomy and space technology to explore outer space. While the exploration of space is carried out mainly by astronomers with telescopes, its physical exploration though is conducted both by robotic spacec ...

Supercritical carbon dioxide Supercritical carbon dioxide (s) is a fluid state of carbon dioxide where it is held at or above its critical temperature and critical pressure. Carbon dioxide usually behaves as a gas in air at standard temperature and pressure (STP), or as ...

closed-cycle gas turbines are under development; "The main advantage of the supercritical CO₂ cycle is comparable efficiency with the helium Brayton cycle at significantly lower temperature" (550 °C vs. 850 °C), but with the disadvantage of higher pressure (20 MPa vs. 8 MPa). Sandia National Laboratories has a goal of developing a 10 MWe supercritical CO₂ demonstration CCGT by 2019.Sandia National Laboratories: Supercritical CO2-Brayton Cycle
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References

*http://www.appliedthermalfluids.com/home/brands-manufacturers/exxonmobil-aviation-jet-oils/mobil-jet-oils/

External links

US Patent 5309492
"Control for a closed cycle gas turbine system"
Industrial Closed-cycle Gas Turbines for Conventional and Nuclear Fuel
(1967) * (at Sandia National Laboratories, 2014)
"Aviation Jet Oils"
{{Heat engines, state=uncollapsed Gas turbines External combustion engines

Background

Nuclear power

Development

See also

References

External links