Air Conditioning

The desire to cool air for comfort predates history. The record begins around 200 AD when Chinese inventor Ding Huan of the Han Dynasty invented a human powered 7 wheel fan that was nearly 10 feet in diameter. 500 years later Emperor Xuanzong built a water-powered fan that included fountains in the Imperial Palace.

In 1758, Benjamin Franklin and John Hadley, a chemistry professor at Cambridge University, studied evaporation as a means of cooling. They found that highly volatile liquids such as alcohol and ether could be evaporated to cool a thermometer down to 7F in ambient air of 64F.

Working with ammionia in 1820, British inventor Michael Faraday that it could be evaporated to chill air. Dr. John Gorrie used a compressor to create ice, that was then used to cool air for patients in his hospital in Apalachicola, Florida. He believed his ice-making machine could be used to cool buildings and even cities. Gorrie patented his ice making machine in 1851 but failed to find commercial success when when his lead backer died and left him without the money to proceed

The first modern air conditioner was invented by Willis Haviland Carrier in Buffalo, New York in 1902. While working at Buffalo Fortge Company, Carrier experimented with air conditioning as a way to improve the manufacturing process in a printing plant. The biggest issue was humidity and Carrier's invention removed it. Rather than sending air through hot coils, he sent it through cold coils (ones filled with cold water). The air blowing over the cold coils cooled the air, and thereby controlled the amount of moisture. This enabled the paper being printed to hold dimensions and made better ink alignment possible. Carrier's invention was later used to improve productivity by making the working environment more comfortable.

The term "air conditioning" was created by Stuart W. Cramer of Charlotte, North Carolina when was seeking to add moisture to the air in his textile mill in 1906. He combined moisture with ventilation to "condition" and change the air in the factories.

The first air conditioners and refrigerators employed toxic or flammable gases, such as ammonia, methyl chloride, or propane. In 1928 Thomas Midgley, Jr. created Freon, the first non-flammable, non-toxic chlorofluorocarbon gas. Freon was found to deplete ozone from the atmosphere and has been phased out.

Several non-ozone-depleting refrigerants have since been developed as alternatives, including Puron, which is used in many air conditioners today.