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.
Claude Gordon Douglas
Claude Gordon Douglas FRS (26 February 1882 in Leicester – 23 March 1963 in Radcliffe Infirmary, Oxford) was a British physiologist, known for his research on respiratory physiology and the invention of the Douglas Bag.