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.
Ding Huan
Ding Huan (丁緩) was a Chinese engineer, inventor, and craftsman who lived in the first century BC during the Han dynasty. Among the inventions attributed to him is an air conditioning system based on evaporative cooling.