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.
Thomas Fowler (inventor)
Fowler patented the thermosiphon in 1828 (British patent number 5711). It was the first convective heating system. A system based on his design was installed at Bicton, part of the Rolle Estate and received great acclaim in the "Gardener's Magazine" of 1829. Unfortunately due to innate flaws in the patent system of the time (under which a new version of a design with minimal changes was not covered by the original patent), the thermosiphon was copied by numerous other manufacturers and Fowler did not have sufficient funds to conduct legal proceedings.