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.
Thomas Fowler (inventor)
Thomas Fowler (born 1777 in Great Torrington, Devon, England – died 31 March 1843) was an English inventor whose most notable invention was the thermosiphon which formed the basis of early hot water central heating systems. He also designed and built an early mechanical calculator.