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.
Dave Lennox
David Lennox (April 15, 1855 – February 15, 1947) was an American inventor and businessman. A furnace manufacturing business he founded in 1895 in Marshalltown, Iowa evolved into what is today known as Lennox International, a global corporation specializing in air conditioning, heating, and commercial refrigeration. Lennox helped to develop what has been described as the first riveted-steel furnace in 1895. His contributions to furnace design have been described as significant steps forward in durability and efficiency from the cast iron furnaces commonly in use near the end of the 19th century.