History of the Air Conditioner
Air conditioning(A/C) removes heat from an indoor environment for overall comfort. Air conditioning may also consist of other aspects of indoor thermal regulation, such as cooling, heating, ventilation (PDF) and disinfection. Anair conditioning unit, an appliance, machine or system, stabilizes the humidity and air temperature within a confided area. These thermal regulation systems use a refrigeration or evaporative cycle to achieve the desired results.
The oldest traces to the concept of air conditioning emerged out of 2nd century China of the Hans Dynasty. Ding Huang invented a rotary fan model with seven wheels that was manually powered. Emperor Xuanzong of the Tang Dynasty ordered the construction of the Cool Hall, a water-powered fan wheels using water fountain jet streams. Despite the technological advancement, the ancient Romans applied earlier concepts using aqueduct water to circulate through houses in attempt to cool them. Ancient Persia developed techniques that used cisterns and wind towers as a cooling operation for buildings. Modern air conditioning advancements emerged out of the 19th century by pioneering chemists, such as Benjamin Franklin and John Hadley. However, Dr. John Gorrie, a native of Apalachicola, Florida, invented the first recognizable cooling appliance in the 1830s. Gorrie's design consisted of a machine motor that blew air across blocks of ice to cool hospital rooms. Likewise, President James Garfield ordered a group of naval engineers to construct a cooling machine that would blow air through ice cold pieces of cloth. Garfield's project was successful, despite a minor improvement and wasteful disposal of ice.
Willis Haviland Carrier developed the first electrical air conditioning unit in 1902. Carrier's invention aimed to control both air temperature and humidity by sending air through cold coils. The air blowers directed streams over the cold coils to bring down the overall atmospheric temperature, thereby leading to moisture control. Carrier's concepts were applied to the workplace, which led to the formation of "The Carrier Air Conditioning Company of America."Stuart W. Cramer explored various methods that introduced air to textile mills by combining moisture and ventilation for conditioning the air and humidity in factories. His evaporative techniques now engulf the concept of evaporative cooling.
The first air conditioning and refrigeration models used toxic or flammable gases to improve the overall atmospheric thermal temperature. Some of these toxic chemicals included ammonia, methly chlorida and propane, which would ignite causing fatal accidents if leakages existed. In 1928, Thomas Midgely Jr. invented the first chlorofluorocarbon gas also known as Freon to the modern industry. Hydrogenated CFC refrigerant, such as R-11, R-12, R-22 and R-134A, are used to expand home and building air conditioning. R-12 was employed in U.S. automobiles until 1994 before transitioning to R-134A. Concerns over the environmental impact made by Freon emissions have become the forefront since the growing increase of global warming.
Air conditioning systems may exhibit an unnoticeable health risk. Microorganisms, such as Legionella pneumophila, a vicious bacterium that leads to the Legionnaires' disease, can spread throughout the confined areas. It is vitally important for owners to call a professional for regular servicing in order to keep the system clean of these dangerous microorganisms. However, air conditioning may also improve the overall filtration, cooling, disinfection and humidification of confined areas that need a sanitary and hypoallergenic atmosphere. Air conditioning may also help extend lives of the elderly during serious heat waves.
Air conditioners help promote a comfortable cabin temperature free of excessive heat and humidity while traveling. Air conditioning may not increase the overall fuel efficiency of a vehicle because of the wind resistance, engine power and aerodynamics causing a direct impact on gas mileage. The first automobile air conditioning was released in 1933 from a company located in New York City, which offered air conditioning installation for cars. Most of the clients for these installations were limousine and high-end cars for the upper class. In 1939, Packard Motor Car Company built air conditioners directly into its cars. These optional units were installed at a modest equivalent of $4,050 United States dollars. The Nash Ambassador was the first American automobile to have a fully-integrated heating, ventilating, and air-conditioning system. About twenty percent of all American cars were equipped with air conditioning in 1960, and grew to 54 percent by 1964.
Portable air conditioners are equipped with wheels for easy transportation inside and out of a home or building. Portable air conditioners consists of an evaporative or refrigerative, split or hosed system. These systems use a compressor to exchange air for heat, dehumidifying the air while cooling it. It rounds up condensation from cooled air, and produces hot air that will need to be vented outside of the cooled area. A portable split system uses flexible pipes, while hosed systems vents through a series of air ducts. Portable evaporative air coolers are not equipped with a compressor or condenser, but instead evaporates water on the cooling fins, which releases the vapor into the various cool areas.
Heat pumps (PDF) relocate heat from one location (heatsink) to another at a lower temperature. A heat pump provides either heating or cooling, while using the same refrigeration cycle. Therefore, a heat pump switches between a condenser or evaporator through a reversing valve. Cooler climates might require homes and buildings to only have strictlyheat pumps (PDF) without the cooling aspect. Food refrigerators, freezers, air conditioners, and split heat pumps provide ample space heating. Heat pumps are usually referred to as vapor-compression refrigeration devices, which include reversing valves and heat exchangers in order to reverse the overall heat flow. Heat pumps draw heat from the ground to accomplish this function.