The ancient Romans tried to keep their buildings cool during hot weather by pumping water from aqueducts through the walls of their houses, whereas in Southeast Asia people hung wet grass mats over the windows to lower the temperature of air inside. Modem air conditioning, which arrived in 1902, is the continuation of this rudimentary principle.
Willis Carrier (1876-1950) of Buffalo, New York, developed the fundamental scientific theories of air conditioning. His first system was designed for use in a printing plant. Changes in the temperature and humidity of the plant were causing the ink nozzles to be out of line, which made color printing problematic. Carrier was assigned with the task of fixing this problem. His early system, which made use of spraying nozzles to cool and dehumidify the air, was large, extremely expensive, and rather dangerous because it relied on the use of ammonia as a coolant. For years, his machines were just used to cool machines, but when the potential to cool people was spotted, they began to be installed in other commercial buildings, such as offices, hotels, and hospitals. He even went on to place units in the United States Senate and the White House. Air conditioning has made life more comfortable and led to greater economic activity in the summer months. It can also reduce death rates from heat-related illnesses by up to 40 percent.
Carrier refined his designs and in 1922 installed a system at a Los Angeles theater where conditioned air was fed in from the ceiling and exhausted at floor level. The Carrier Corporation continues to make and install air conditioning systems all over the world.
