06.19 Stirling Engine News
Rev. Robert Stirling (October 25, 1790 - June 6, 1878)
Rev Robert Stirling was born at Cloag Farm near Methven, Perthshire in Scotland, the third of eight children, son of Patrick Stirling and Agnes Stirling. He inherited his father's interest in engineering, but studied divinity and became a minister of the Church of Scotland in 1816. He soon became concerned about the danger the workers in his parish faced from steam engines, which frequently exploded because ofthe poor quality of the iron boiler plate available at the time, and decided to improve the design of an existing air engine in the hope that it would provide a safer alternative. Within a year he invented a regenerator, which he called the Heat Economiser, a device for improving the efficiency of an air engine. He obtained a patent for the economiser, and an air engine incorporating it, in 1817. Stirling's engine could not explode, because it worked at a lower pressure, and could not cause steam burns. In 1818 he built the first practical version of his engine, used to pump water from a quarry.
In 1819 Stirling married Jean Rankin. They had seven children, including the locomotive engineers Patrick Stirling and James Stirling(engineer).
Later, in Kilmarnock, he collaborated with another inventor, Thomas Morton, who provided workshop facilities for Stirling's research. Both men were interested in astronomy, and having learnt from Morton how to grind lenses, Stirling invented several optical instruments.
Robert's brother James, also an engineer, built a large air engine at his Dundee Foundry Company.
In a letter of 1876, Robert Stirling acknowledged the importance of Henry Bessemer's new invention - the Bessemer process for the manufacture of steel - which made steam engines safer and threatened to make the air engine obsolete. However, he also expressed a hope that the new steel would improve the performance of air engines.
Stirling died in Galston, East Ayrshire.
The theoretical basis of Stirling's engine, the Stirling cycle, would not be fully understood until the work of Sadi Carnot (1796 - 1832). Carnot produced (and published in 1825) a general theory of heat engines, the Carnot cycle, of which the Stirling cycle is a similar case.
Fast Forward ~200 years ...
The Stirling Technology Corp (now Infinia Corp) has developed a high efficiency Stirling Engine power generator for NASA deep space missions. These newly designed units are capable of over 14 years service with zero maintenance, significantly reduced vibration (needed for high performance imaging) and higher energy conversion efficiency. Infinia is also developing a 3KW solar power generator for both business and consumers based on their NASA engine. This product is designed to produce up to 9 megawatt hours per unit per year with 24% conversion of solar power to electricity.
Robert would be proud.