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.
Samuel Dalziel Heron
Samuel Dalziel Heron (18 May 1891 – 10 July 1963) was a British born aerospace engineer who made major contributions to the design of piston engines. While working in Britain he carried out the first systematic research into air-cooled cylinders. In the U.S.A he contributed to the design of the Curtiss R1454, invented the sodium cooled poppet valve and became technical director for aeronautical research for the Ethyl Corporation.