Willis Carrier
Willis Haviland Carrier (November 26, 1876 – October 7, 1950) was an American engineer, best known for inventing modern air conditioning. Carrier invented the first electrical air conditioning unit in 1902. In 1915, he founded Carrier Corporation, a company specializing in the manufacture and distribution of heating, ventilation, and air conditioning (HVAC) systems.
Scroll compressor
Léon Creux first patented a scroll compressor in 1905 in France and the US (Patent number 801182).
Creux invented the compressor as a rotary steam engine concept, but the metal casting technology of the period was not sufficiently advanced to construct a working prototype, since a scroll compressor demands very tight tolerances to function effectively. The first practical scroll compressors did not appear on the market until after World War II, when higher-precision machine tools enabled their construction. They were not commercially produced for air conditioning until 1983 when Hitachi launched the world's first air conditioner with a scroll compressor.