Ever since Ding Huan, a Chinese inventor, produced a rotary fan in the 2nd century
man has been trying to find new ways of keeping themselves cool in hot temperatures. The Chinese were the early innovators in this field, with the Tang Dynasty in the 700s AD and the Song Dynasty in the 900s AD continuing the trend when they pioneered the use of enormous water powered fans as air conditioning.
Air conditioning was advanced further by the Persians in medieval times. Their system used huge cisterns of collected rain water and a system of wind towers which were used to direct hot air into the building in such a way as to pass over this water collection. The heat from the air evaporated the water and this helped to cool the building. This method was used all over the Arab world during these times.
The next innovation in air conditioning was by the Egyptians of the Middle Ages when they invented the ventilator. These were widely used in houses throughout Egypt, and is was reported at the time that nearly every home in Cairo had one.
In an experiment at Cambridge University in the 1700s two professors performed an experiment to study the effects of evaporation of volatile liquids such as alcohol. The experiment concluded that it would be conceivably possible to '...freeze a man to death on a warm summer's day.' The chilling potential of liquid ammonia was discovered by Michael Faraday in the 19th century, and in the same century a man from Florida called John Gorrie made a machine that could make ice using compressor technology. Gorrie hoped he could make a machine to cool entire cities and was granted a patent but the project came to a halt when his financial backer died and the device was never built.
The first machine that resembles a modern air conditioning machine was developed in 1902 by New Yorker Willis Carrier. The machine was developed to control the temperature in a large printing factory and his machine was able to control temperature and humidity by blowing air through cold coils. This machine was taken on by other companies in order to cool down workers and increase productivity and was the beginning of the modern air conditioning system.