Editing Stirling engine (section)

=== Invention and early development ===
The Stirling engine (or Stirling's air engine as it was known at the time) was invented and patented in 1816.<ref name="Sier-1999" /> It followed [[Hot air engine#History|earlier attempts at making an air engine]] but was probably the first put to practical use when, in 1818, an engine built by Stirling was employed pumping water in a [[quarry]].<ref name="Finkelstein-2001-2.2" /> The main subject of Stirling's original patent was a heat exchanger, which he called an "[[economiser]]" for its enhancement of fuel economy in a variety of applications. The patent also described in detail the employment of one form of the economiser in his unique closed-cycle [[hot air engine|air engine]] design<ref name="patent-1816" /> in which application it is now generally known as a "[[#Regenerator|regenerator]]". Subsequent development by Robert Stirling and his brother [[James Stirling (1800–1876)|James]], an engineer, resulted in patents for various improved configurations of the original engine including pressurization, which by 1843, had sufficiently increased power output to drive all the machinery at a [[Dundee]] iron foundry.<ref name="Sier-1995-93" />

A paper presented by James Stirling in June 1845 to the [[Institution of Civil Engineers]] stated that his aims were not only to save fuel but also to create a safer alternative to the [[steam engine]]s of the time,<ref name="Sier-1995-92" /> whose [[boiler]]s frequently exploded, causing many injuries and fatalities.<ref name="Nesmith-1985" /><ref name="Chuse-1992-1" /> This has, however, been disputed.<ref name="Organ-2008a" />

The need for Stirling engines to run at very high temperatures to maximize power and efficiency exposed limitations in the materials of the day, and the few engines that were built in those early years suffered unacceptably frequent failures (albeit with far less disastrous consequences than boiler explosions).<ref name="Sier-1995-94" /> For example, the Dundee foundry engine was replaced by a steam engine after three hot cylinder failures in four years.<ref name="Finkelstein-2001-30" />