Science and technology of the 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" (唐語林) 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.
Schuyler Wheeler
Schuyler Skaats Wheeler (May 17, 1860 – April 20, 1923) was an American electrical engineer and manufacturer who invented the electric fan, the electric elevator, and the electric fire engine. He helped develop and implement a code of ethics for electrical engineers.