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FreonBy Mary BellisRefrigerators from the late 1800s until 1929 used the toxic gases, ammonia (NH3), methyl chloride (CH3Cl), and sulfur dioxide (SO2), as refrigerants. Several fatal accidents occurredin the 1920s because of m ethyl chloride leakage from refrigerators. People started leavingtheir refrigerators in their backyards. A collaborative effort began between three Am erican corporations, Frigidaire, General Motors and DuPont to search for a less dangerous method of refrigeration.In 1928, Thom as Midgley, Jr. aided by Charles Franklin Kettering invented a "miraclecom pound" called Freon. Freon represents several different chlorofluorocarbons, or CFCs, which are used in commerce and industry. The CFCs are a group of aliphatic organiccom pounds containing the elem ents carbon and fluorine, and, in m any cases, other halogens (especially chlorine) and hydrogen. Freons are c olorless, odorless, nonflammable, noncorrosive gases or liquids.Side Note: Charles Franklin Kettering invented the first electric autom obile ignition system. He was also the vice-president of the General Motors Research Corporation from 1920 to 1948. General Motors' scientist, Thom as Midgley invented leaded (ethyl) gasoline.Thom as Midgley was chosen by Charles Franklin Kettering to head the research into the new refrigerants. Frigidaire was issued the first patent, US#1,886,339, for the formula for CFCs on December 31, 1928.In 1930, General Motors and DuPont formed the Kinetic Chemical Company to produce Freon. By 1935, Frigidaire and its com petitors had sold 8 million new refrigerators in the United States using Freon m ade by the Kinetic Chemical Company. In 1932, the Carrier Engineering Corporation used Freon in the world's first self-contained home air conditioningunit, called an "Atmospheric Cabinet".Side Note: The trade name Freon ® is a registered trademark belonging to E.I. du Pont de Nemours& Company (DuPont).Because Freon is non-toxic, it eliminated the danger posed by refrigerator leaks. In just a few years, com pressor refrigerators using Freon would becom e the standard for almost all hom e kitchens. In 1930, Thom as Midgley held a demonstration of the physical properties ofFreon for the Am erican Chemical Society by inhaling a lung-full of the new wonder gas and breathing it out onto a candle flam e, which was extinguished, thus showing the gas'snon-toxicity and non-flammable properties. Only decades later did people realize that such chlorofluorocarbons endangered the ozone layer of the entire planet.Side Note: CFCs, or Freon, are now infamous for greatly adding to the depletion of the earth's ozone shield. Leaded gasoline is also a m ajor pollutant, and Thom as Midgley secretly suffered from lead poisoning because of his invention, a fact he kept hidden from the public.Thom as Midgley discoveries ranged from a way of getting salt into popcorn before it was popped, to a m ethod for treating the contents of a swimming pool so that people c ould swim farther underwater.The History of the Refrigerator and FreezersBefore mechanical refrigeration system s were introduced, people cooled their food with ice and snow, either found locally or brought down from the mountains. The first cellars were holes dug into the ground and lined with wood or straw and packed with snow and ice: this was the only m eans of refrigeration for most of history.Refrigeration is the process of removing heat from an enclosed space, or from a substance, to lower its tem perature. A refrigerator uses the evaporation of a liquid to absorb heat. The liquid, or refrigerant, used in a refrigerator evaporates at an extrem ely low tem perature,creating freezing tem peratures inside the refrigerator. It's all based on the following physics:- a liquid is rapidly vaporized (through com pression) - the quickly expanding vapor requires kinetic energy and draws the energy needed from the immediate area - which loses energy and becom es cooler. Cooling caused by the rapid expansion of gases is the primary means of refrigeration todayThe first known artificial refrigeration was dem onstrated by William Cullen at the University of Glasgow in 1748. However, he did not use his discovery for any practical purpose. In 1805, an Am erican inventor, Oliver Evans, designed the first refrigeration machine. The firstpractical refrigerating m achine was built by Jacob Perkins in 1834; it used ether in a vaporcom pression cycle. An Am erican physician, John Gorrie, built a refrigerator based on Oliver Evans' design in 1844 to m ake ice to cool the air for his yellow fever patients. German engineer Carl von Linden, patented not a refrigerator but the process of liquifying gas in 1876 that is part of basic refrigeration technology.Side Note: Improved refrigerator designs were patented by African Am erican inventors,Thomas Elkins (11/4/1879 U.S. patent #221,222) and John Standard (7/14/1891 U.S. patent #455,891).Refrigerators from the late 1800s until 1929 used the toxic gases ammonia (NH3), m ethyl chloride (CH3Cl), and sulfur dioxide (SO2) as refrigerants. Several fatal accidents occurred in the 1920s when m ethyl chloride leaked out of refrigerators. Three Am erican corporations launched collaborative research to develop a less dangerous method of refrigeration; theirefforts lead to the discovery of Freon. In just a few years, com pressor refrigerators usingFreon would becam e the standard for almost all hom e kitchens. Only decades later, would people realize that these chlorofluorocarbons endangered the ozone layer of the entire planet.History of Sealed Refrigeration SystemsOne hundred years ago, refrigeration engineers began to search for a perm anent solution to the problem of leaky refrigeration system s.The History of the RefrigeratorFrom the History Channel, a cool, sim ple outline of the "History of the Refrigerator".The Refrigerator"At som e point, perhaps in fourteenth century China or seventeenth century Italy, it was discovered that the evaporation of brine (salt water) absorbed heat and there fore a container placed in brine would stay cold." This short essay discusses the highlights of refrigerator history.History of Sealed Refrigeration Systems One hundred years ago, refrigeration engineers began to search for a perm anent solution to the problem of leaky refrigeration system s. The History of the Refrigerator From the History Channel, a cool, simple outline of the "History of the Refrigerator". The Refrigerator "At som e point, perhaps in fourteenth century China or seventeenth century Italy, it was discovered that the evaporation of brine (salt water) absorbed heat and therefore a container placed in brine would stay cold." This short essay discusses the highlights of refrigerator history. Refrigerant History A mixture called chem ogene (consisting of petrol ether and naphtha) was patented as a refrigerant for vapor compression system s in 1866. Carbon dioxide was introduced as a refrigerant in the same year. Refrigerators - The Physics Handbook The term"refrigerator" was coined by a Maryland engineer, Thomas Moore, in 1800. Moore's device would now be called an "ice box" -- a cedar tub, insulated with rabbit fur,filled with ice, surrounding a sheetm etal container for transporting butter from rural Maryland to Washington, DC. How Refrigerators Work How Refrigerators Work, written by Marshall Brain of How Stuff Works. The Refrigeration Research Museum (1890 - 1960) Who invented the refrigerator? When was it invented? Cooling History The Freezing Process Freezing food involves lowering its temperature to below 0ºC, resulting in the gradual conversion of the water present in the food into ice.The History of Air ConditioningIn 1902, only one year after Willis Haviland Carrier graduated from Cornell University with a Masters in Engineering, the first air (tem perature and humidity) conditioning was in operation, making one Brooklyn printing plant owner very happy. Fluctuations in heat and humidity in his plant had caused the dim ensions of the printing paper to keep altering slightly, enough to ensure a misalignment of the colored inks. The new air conditioning machine created a stable environment and aligned four-color printing becam e possible. All thanks to the new em ployee at the Buffalo Forge Com pany, who started on a salary of only $10.00 per week.The 'Apparatus for Treating Air' (U.S. Pat# 808897) granted in 1906, was the first of several patents awarded to Willis Haviland Carrier. The recognized 'father of air conditioning' is Carrier, but the term'air conditioning' actually originated with textile engineer, Stuart H. Cramer. Cramer used the phrase 'air conditioning' in a 1906 patent claim filed for a device that added water vapor to the air in textile plants - to condition the yarn.In 1911, Willis Haviland Carrier disclosed his basic Rational Psychrometric Form ulae to the American Society of Mechanical Engineers. The form ula still stands today as the basis inall fundamental calculations for the air conditioning industry. Carrier said he received his 'flash of genius' while waiting for a train. It was a foggy night and he was going over in his mind the problem of temperature and humidity control. By the tim e the train arrived, Carrier had an understanding of the relationship between tem perature, humidity and dew point.Industries flourished with the new ability to control the tem perature and humidity levels during and after production. Film, tobacco, processed m eats, m edical capsules, textiles and other products acquired significant im provem ents in quality with air conditioning. Willis and six other engineers formed the Carrier Engineering Corporation in 1915 with a startingcapital of $35,000 (1995 sales topped $5 billion). The company was dedicated to im proving air conditioning technology.In 1921, Willis Haviland Carrier patented the centrifugal refrigeration m achine. The 'centrifugal chiller' was the first practical m ethod of air conditioning large spaces. Previous refrigeration machines used reciprocating-compressors (piston-driven) to pump refrigerant (often toxic and flammable ammonia) throughout the system. Carrier designed a centrifugal-com pressor similar to the centrifugal turning-blades of a water pump. The result was a safer and m ore efficient chiller.Cooling for human com fort, rather than industrial need, began in 1924, noted by the three Carrier centrifugal chillers installed in the J.L. Hudson Depart m ent Store in Detroit, Michigan. Shoppers flocked to the 'air condit ioned' store. The boom in human cooling spread from the depart ment stores to the m ovie theaters, m ost notably the Rivoli theater in New York, whose summer film business skyrocketed when it heavily advertised the cool com fort. Demand increased for smaller units and the Carrier Company obliged.In 1928, Willis Haviland Carrier developed the first residential 'Weathermaker', an air conditioner for private home use. The Great Depression and then WW2 slowed the non-industrial use of air conditioning. After the war, consum er sales started to grow again. The rest is history, cool and com fortable history.Willis Haviland Carrier did not invent the very first system to cool an interior structure, however, his system was the first truly successful and safe one that st arted the science of modern air conditioning. You can read about the earlier history of air conditioning in the recommended reading m aterial listed in the left sidebar.。