Tang dynasty
The inventor Ding Huan (fl. 180 AD) of the Han dynasty invented a rotary fan for air conditioning, with seven wheels 3 m (10 ft) in diameter and manually powered. In 747, Emperor Xuanzong had a "Cool Hall" built in the imperial palace, which the "Tang Yulin" () describes as having water-powered fan wheels for air conditioning as well as rising jet streams of water from fountains. During the subsequent Song dynasty, written sources mentioned the air conditioning rotary fan as even more widely used.
Charles Gordon Curtis
Charles Gordon Curtis (April 20, 1860 in Boston – March 1953 in Central Islip, Suffolk County, New York) was an American engineer, inventor, and patent attorney. He is best known as the developer of the eponymous Curtis steam turbine.