Timeline
1902	Willis Haviland Carrier designs a humidity control process and pioneers modern air conditioning.
1907	First overseas sale of a Carrier system was made to a silk mill in Yokohama, Japan.
1911	Carrier presents his paper "Rational Psychometric Formulae" to the American Society of Mechanical Engineers and thereby forms the basis of modern air-conditioning.
1914	Clarence Birdseye pioneers the freezing of fish for later defrosting and cooking.
1915	Carrier Corp. is founded under the name Carrier Engineering.
1920s	Carrier introduces small air-conditioning units for small businesses and residences.
1922	Carrier develops the centrifugal refrigeration machine.
1925	Clarence Birdseye and Charles Seabrook develop a deep-freezing process for cooked foods that Birdseye patents in 1926.
1927	General Electric introduces a refrigerator with a "monitor top" containing a hermetically sealed compressor.
1929	U.S. electric refrigerator sales top 800,000, and the average price of a refrigerator falls to $292.
1930s	Air conditioners are placed in railroad cars transporting food and other perishable goods.
1931	GM's Frigidaire division adopts Freon 12 (dichlorodifluoromethane) refrigerant gas, invented by Thomas Midgley of Ethyl Corp. and Charles Kettering of GM.
1931	Birds Eye Frosted Foods go on sale across the U.S. as General Foods expands distribution.
1937	Air conditioning is first used for mining in the Magma Copper Mine in Superior, Arizona.
1938	Window air conditioner marketed by Philco-York.
1939	The first air-conditioned automobile is engineered by Packard.