Timeline of United States inventions (1890–1945)
Air conditioning is the cooling and de-humidification of indoor air for thermal comfort. Using a system of coils as a solution to cool and remove moisture from muggy air in a printing plant that was wrinkling magazine pages, Willis Carrier invented and manufactured the world's first mechanical air conditioning unit in 1902. Carrier's invention – encompassing the first system to provide man-made control over temperature, humidity, ventilation and air quality, was first installed as a solution to the quality problems experienced at a Brooklyn printing plant, Sackett-Wilhelms Lithographing and Publishing Company. Air conditioning not only spawned a company and an industry, but also brought about profound economic, social and cultural changes.
Air conditioning
In 1758, Benjamin Franklin and John Hadley, a chemistry professor at Cambridge University, conducted an experiment to explore the principle of evaporation as a means to rapidly cool an object. Franklin and Hadley confirmed that evaporation of highly volatile liquids (such as alcohol and ether) could be used to drive down the temperature of an object past the freezing point of water. They conducted their experiment with the bulb of a mercury thermometer as their object and with a bellows used to speed up the evaporation. They lowered the temperature of the thermometer bulb down to while the ambient temperature was . Franklin noted that, soon after they passed the freezing point of water , a thin film of ice formed on the surface of the thermometer's bulb and that the ice mass was about thick when they stopped the experiment upon reaching . Franklin concluded: "From this experiment one may see the possibility of freezing a man to death on a warm summer's day."