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.
Charles Gilbert Gates
Charles Gilbert Gates was the son of John Warne Gates, the pioneer manufacturer of barbed wire. In July 1913 he drove from his home in Minneapolis to New York City, where he had a seat on the New York Stock Exchange. He died in Cody, Wyoming in 1913. After his death his home was completed and was the first to have air conditioning installed.