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.
Icemaker
In 1748, the first known artificial refrigeration was demonstrated by William Cullen at the University of Glasgow. Mr. Cullen never used his discovery for any practical purposes. This may be the reason why the history of the icemakers begins with Oliver Evans, an American inventor who designed the first refrigeration machine in 1805. In 1834, Jacob Perkins built the first practical refrigerating machine using ether in a vapor compression cycle. The American inventor, mechanical engineer and physicist received 21 American and 19 English patents (for innovations in steam engines, the printing industry and gun manufacturing among others) and is considered today the father of the refrigerator.