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A Stirling engine is a heat engine that operates by cyclic compression and expansion of air or other gas (the ''working fluid'') at different temperatures, such that there is a net conversion of heat energy to mechanical work.〔"Stirling Engines", G. Walker (1980), Clarenden Press, Oxford, page 1: "A Stirling engine is a mechanical device which operates on a *closed * regenerative thermodynamic cycle, with cyclic compression and expansion of the working fluid at different temperature levels."〕〔W.R. Martini (1983), p.6〕 More specifically, the Stirling engine is a closed-cycle regenerative heat engine with a permanently gaseous working fluid. ''Closed-cycle'', in this context, means a thermodynamic 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 thermal store, known as the ''regenerator''. The inclusion of a regenerator 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.〔T. Finkelstein; A.J. Organ (2001), Chapters 2&3〕 The Stirling engine is noted for high efficiency compared to steam engines,〔(Stirling engines have reached 50% efficiency )〕 quiet operation, and its ability to use almost any heat source. The heat energy source is generated external to the Stirling engine rather than by internal combustion as with the Otto cycle or Diesel cycle engines. Because the Stirling engine is compatible with alternative and renewable energy sources it could 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 and power (CHP) units, in which it is more efficient and safer than a comparable steam engine.〔Sleeve notes from A.J. Organ (2007)〕〔F. Starr (2001)〕 However, it has a low power-to-weight ratio 〔 rendering it more suitable for use in static installations where space and weight are not at a premium. == Name and classification == Robert Stirling was a Scottish minister who invented the first practical example of a closed cycle air engine in 1816, and it was suggested by Fleeming 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 their individual 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.〔C.M. Hargreaves (1991), Chapter 2.5〕 However, nearly thirty years later, Graham Walker still had cause to bemoan the fact such terms as 'hot air engine' remained interchangeable with 'Stirling engine', which itself was applied widely and indiscriminately;〔Graham Walker (1971) Lecture notes for Stirling engine symposium at Bath University. Page 1.1 "Nomenclture"〕 a situation that continues.〔http://www.stirlingbuilder.com/survey/survey-results〕 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 combustion process 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. Most of the many possible implementations of the Stirling engine fall into the category of reciprocating piston engine. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Stirling engine」の詳細全文を読む スポンサード リンク
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