This Timeline of heat engine technology describes how heat engines have been known since antiquity but have been made into increasingly useful devices since the 17th century as a better understanding of the processes involved was gained. They continue to be developed today.
A heat pump is a heat engine run in reverse. Work is used to create a heat differential. The timeline includes devices classed as both engines and pumps, as well as identifying significant leaps in human understanding.
1759 - John Harrison uses a bimetallic strip in his third marine chronometer (H3) to compensate for temperature-induced changes in the balance spring. This converts thermal expansion and contraction in two dissimilar solids to mechanical work.
1769 - James Watt patents his first improved atmospheric steam engine, see Watt steam engine with a separate condenser outside the cylinder, doubling the efficiency of earlier engines.
1834 - Jacob Perkins, obtained the first patent for a vapor-compression refrigeration system.
1850s - Rudolf Clausius sets out the concept of the thermodynamic system and positioned entropy as being that in any irreversible process a small amount of heat energy δQ is incrementally dissipated across the system boundary
1861 - Alphonse Beau de Rochas of France originates the concept of the four-stroke internal-combustion engine by emphasizing the previously unappreciated importance of compressing the fuel–air mixture before ignition.
1861 - Nikolaus Otto patents a two-stroke internal combustion engine building on Lenoir's.
1872 - Pulsometer steam pump, a pistonless pump, patented by Charles Henry Hall. It was inspired by the Savery steam pump.
1873 - The British chemist Sir William Crookes invents the light mill a device which turns the radiant heat of light directly into rotary motion.
1877 - Theorist Ludwig Boltzmann visualized a probabilistic way to measure the entropy of an ensemble of ideal gas particles, in which he defined entropy to be proportional to the logarithm of the number of microstates such a gas could occupy.
1942 - R.S. Gaugler of General Motors patents the idea of the Heat pipe, a heat transfer mechanism that combines the principles of both thermal conductivity and phase transition to efficiently manage the transfer of heat between two solid interfaces.
1950s - The Philips company develop the Stirling-cycle Stirling Cryocooler which converts mechanical energy to a temperature difference.
1959 - Geusic, Schultz-DuBois and Scoville of Bell Telephone Laboratories USA build a Three Level Maser which runs as a quantum heat engine extracting work from the temperature difference of two heat pools.
1962 - William J. Buehler and Frederick Wang discover the Nickel titanium alloy known as Nitinol which has a shape memory dependent on its temperature.
2011 - Michigan State University builds the first wave disk engine. An internal combustion engine which does away with pistons, crankshafts and valves, and replaces them with a disc-shaped shock wave generator.
^Lardner, Dionysius (1840). The Steam Engine Explained and Illustrated. Taylor and Walton. p. 22. Full title: Le Machine volume nuovo, et di molto artificio da fare effetti maravigliosi tanto Spiritali quanto di Animale Operatione, arichito di bellissime figure. Del Sig. Giovanni Branco, Cittadino Romano. In Roma, 1629
^Shoichi Toyabe; Takahiro Sagawa; Masahito Ueda; Eiro Muneyuki; Masaki Sano (2010-09-29). "Information heat engine: converting information to energy by feedback control". Nature Physics. 6 (12): 988–992. arXiv:1009.5287. Bibcode: 2011NatPh...6..988T. doi:10.1038/nphys1821. We demonstrated that free energy is obtained by a feedback control using the information about the system; information is converted to free energy, as the first realization of Szilard-type Maxwell’s demon.