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.
Leonard L. Northrup Jr.
After the War, Northrup went to work for Storm Vulcan, a Dallas company, where he invented a machine to clean aircraft engines. He also embarked on a venture to fit cars with air conditioning equipment, putting the machinery in the trunk and piping the cooled air through tubes in the headliner. This caught the interest of engineers from General Motors, who copied the system in Cadillacs in the late 1940s. "After market" automotive AC units were manufactured in Texas until the 1980s. He also sold some of the first air conditioning units, built by the Curtis Mathes Corporation, an early leader in manufacturing window units. Northrup married Jane Keliher and started a family in Dallas, where he designed and built one of the first single-family houses in the United States with central air conditioning. He founded a company to install air conditioning in residential and commercial buildings. With a Marketing Plan from G F Sweetman (CEO of American Awards Co), he became one of largest suppliers of Curtis Mathes fans and compressors in the nation. He also developed a company to manage, install, update, and clean air filtration systems.