Air conditioning
Modern air conditioning emerged from advances in chemistry during the 19th century, and the first large-scale electrical air conditioning was invented and used in 1902 by US inventor Willis Carrier. The introduction of residential air conditioning in the 1920s helped enable the great migration to the Sun Belt in the United States.
George Cayley
According to the Institution of Mechanical Engineers George Cayley was the inventor of the hot air engine in 1807: "The first successfully working hot air engine was Cayley's, in which much ingenuity was displayed in overcoming practical difficulties arising from the high working temperature." His second hot air engine of 1837 was a forerunner of the internal combustion engine: "In 1837, Sir George Cayley, Bart., Assoc. Inst. C.E., applied the products of combustion from close furnaces, so that they should act directly upon a piston in a cylinder. Plate No. 9 represents a pair of engines upon this principle, together equal to 8 HP, when the piston travels at the rate of 220 feet per minute."