Sist. Hidraulico

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Stirling engine
From Wikipedia, the free encyclopedia

Alpha type Stirling engine. There are two cylinders. The expansion cylinder (red) is maintained at a high temperature while the compression cylinder (blue) is cooled. The passage between the two cylinders contains the regenerator.

Beta Type Stirling Engine. There is only one cylinder,hot at one end and cold at the other. A loose fitting displacer shunts the air between the hot and cold ends of the cylinder. A power piston at the end of the cylinder drives the flywheel.
For the adiabatic Stirling cycle, see Stirling cycle.
A Stirling engine is a heat engine operating by cyclic compression and expansion of air or other gas, the working fluid, at different temperature levelssuch that there is a net conversion of heat energy to mechanical work.[1][2] Or more specifically, a closed-cycle regenerative heat engine with a permanently gaseous working fluid, where closed-cycle is defined as athermodynamic system in which the working fluid is permanently contained within the system, and regenerative describes the use of a specific type of internal heat exchanger and thermalstore, known as the regenerator. It is the inclusion of a regenerator that differentiates the Stirling engine from other closed cycle hot air engines.
Originally conceived in 1816 as an industrial prime mover to rival the steam engine, its practical use was largely confined to low-power domestic applications for over a century.[3]
The Stirling engine is noted for its high efficiency compared tosteam engines,[4] quiet operation, and the ease with which it can use almost any heat source. This compatibility with alternative and renewable energy sources has become increasingly significant as the price of conventional fuels rises, and also in light of concerns such as peak oil and climate change. This engine is currently exciting interest as the core component of micro combined heat andpower (CHP) units, in which it is more efficient and safer than a comparable steam engine.[5][6]
Contents  [hide]  * 1 Name and classification * 2 Functional description * 3 History * 4 Theory * 5 Analysis * 6 Applications * 7 Alternatives * 8 See also * 9 References * 10 Bibliography * 11 Further reading * 12 External links |
-------------------------------------------------[edit]Name and classification
Robert Stirling was the Scottish inventor of the first practical example of a closed cycle air engine in 1816, and it was suggested byFleeming Jenkin as early as 1884 that all such engines should therefore generically be called Stirling engines. This naming proposal found little favour, and the various types on the market continued to be known by the name of theirindividual designers or manufacturers, e.g. Rider's, Robinson's, or Heinrici's (hot) air engine. In the 1940s, the Philips company was seeking a suitable name for its own version of the 'air engine', which by that time had been tested with working fluids other than air, and decided upon 'Stirling engine' in April 1945.[7] However, nearly thirty years later Graham Walker still had cause to bemoan thefact such terms as 'hot air engine' continued to be used interchangeably with 'Stirling engine', which itself was applied widely and indiscriminately.[8]
Like the steam engine, the Stirling engine is traditionally classified as an external combustion engine, as all heat transfers to and from the working fluid take place through a solid boundary (heat exchanger) thus isolating the combustionprocess and any contaminants it may produce from the working parts of the engine. This contrasts with an internal combustion engine where heat input is by combustion of a fuel within the body of the working fluid.
There are many possible implementations of the Stirling engine most of which fall into the category of reciprocating piston engine.
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