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.
Guillaume Amontons
Guillaume Amontons is also the inventor of the hot air engine. In 1699 he built his first engine, means over one century before the well-known Stirling Engine. This engine, named by Amontons "FIre Mill" was following a new thermodynamic cycle, that later became the Stirling cycle.