The very first building to ever use air conditioning units to both cool and heat the air was the New York Stock Exchange. This took place in 1902. Later that year, Willis Havilland Carrier installed the very first electrically-run air conditioning unit at a printing plant. The unit not only cooled the air but also controlled the humidity.We all know that air conditioning makes you feel cool, but there is more to it than just cooling us down. It means keeping the temperature and humidity (moisture content) of air in an enclosed space, whether it is one room or an entire building, at just the right level for the comfort of the people inside. It can also circulate the air, Accumulator safety valve adding in moisture to it as necessary. During the summer it typically means removing the heat by passing the air over and through cold pipes that collect water from the air itself. This works similar to the way water condenses on a cold glass of water on a hot day. In fact, we might almost say that air conditioning means creating an artificial, comfortable climate.

In this article we shall discuss only cooling.A phoenix air conditioning unit cools the air through a refrigerant, a substance that alters the temperature of the air. In the early stages of its development, air conditioning units used harmful gases such as ammonia and methyl chloride as refrigerants. They were soon replaced by another type of chemical, the patented substance called Freon.Air conditioning has a ton of uses besides keeping us comfortable. Many industries depend on it to keep the air in their plants clean, cool and at the right moisture level. For example, textile fiber such as wool and cotton will stretch or shrink as the moisture content in the air changes. This causes many subtle variations in the quality of the cloth. Too much moisture in the air -or even on a worker's fingertips- will cause delicate metal parts such as rocket components or precision instruments instrument to corrode. The wrong temperature can easily spoil a batch of antibiotic culture. Proper air conditioning prevents this mishap from ever taking place.Air conditioning units usually have different types of refrigeration cycles. The first type uses a heat pump that drives out hot air from the room and brings in cooled air though a compressor. The second type pumps in a refrigerant. When the refrigerant evaporates, it takes with it the hot air and leaves cooled air for us to enjoy. Inventors have tinkered with methods of air conditioning for years. Ancient Egyptians and Romans got some relief from the heat by hanging woven mats soaked with water across to their entrances of their houses, so the air would be could by evaporation.As phoenix air conditioning became more popular during the 1930's, central air conditioning systems were developed.

These could easily cool the whole office or apartment building from one centrally located unit, just as buildings were heated from one big furnace in the basement instead of using little stoves in each room. During the same period of time small units that could air condition a single room were developed. After World War 2 large numbers of small units began to be used in private homes. A later development, used increasingly in public buildings and private homes alike, combined heating and cooling units into one amazing system.To be practical, an air conditioning unit must be able to maintain a consistent temperature. Otherwise people would like just have to turn off their units and then turn them back on throughout the day as the temperature become too cold or hot. A steady temperature-regulating device called thermostat. The thermostat is set at a desired temperature. It then switches the cooling unit on and off as needed throughout the day.