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Refrigerator

Refrigerator Back in time a long time ago, around 500 B.C. the Egyptians and Indians made ice on cold nights by setting water out in earthenware pots and keeping the pots wet. In the 18th century England, servants collected ice in the winter and put it into icehouses, where the sheets of ice were packed in salt, wrapped in strips of flannel and stored underground to keep them frozen until summer. Before the refrigerator or “ice box” was introduced people used snow and ice to keep their food cool, which was either found locally or brought down from the mountains. Cellars and caves were also used to refrigerate food. Meat and fish were preserved in warm weather by salting or smoking. The first cellars were holes dug into the ground and lined with wood or straw and packed with refrigeration for most of history. At the beginning of the 19th century, ice boxes were used in England. These ice boxes were typically made of wood, lined with tin or zinc and insulated with various materials including cork, sawdust or seaweed. They were used to hold blocks of ice and refrigerate food. Ice was delivered as needed (people simply hung the “Ice Today” sign in their window for the delivery man) and a drip pan collected the melted water which then had to be emptied daily. Natural ice was harvested, distributed and used in both commercial and home applications in the mid-1800s. The ice trade between Boston and the South was one of the first casualties of the Civil War. Warm winters in 1898 and 1890 created severe shortages of natural ice in the U.S. This stimulated the use of mechanical refrigeration for the freezing and storage of fish and in the brewing, dairy and meat packing industries. During the nineteenth century, numerous experimental devices were developed in an effort to achieve practical artificial refrigeration. Compressed ether machines were built in Pennsylvania by Oliver Evans in 1805 and in Australia by James Harrison in 1855, and Dr. John Gorrie in Florida built an expanding air-cooling machine in 1844. In 1851 Dr. John Gorrie created the first commercial ice making machine to cool the air for his yellow fever patients. Soon thereafter, refrigeration and freezing became popular methods of preserving foods for transport or storage, and in place where natural ice was not available. Refrigeration is the process of removing heat from an enclosed space, or from a substance, to lower its temperature. A refrigerator uses the evaporation of a liquid to absorb heat. The liquid, or refrigerant used in a refrigerator evaporates at an extremely low temperature creating freezing temperatures inside the refrigerator. William Cullen at the University of Glasgow demonstrated the first known artificial refrigeration in 1748. However, he did not use his discovery for any practical purpose. In 1805, an American inventor, Oliver Evans, designed the first refrigerator machine. The development of mechanical refrigeration systems began in the early19th century and arose mainly from the needs of meat producers in the USA, South America, Australia and New Zealand, who were facing many difficulties in shipping their produce to their export markers in Europe. Many experimental systems were built in the 1830s, utilizing the cooling effect produced by the expansion of compressed air or carbon dioxide or by the evaporation of volatile fluids such as ammonia. The first meat freezing plant was built in Australia in 1861. This company had its own slaughterhouse, freezing plant and cold store and used ammonia compression freezing system. By 1870, ships were successfully transporting chilled beef (cooled to one or two degrees below freezing point) in insulated holds cooled by ice mixed with salt (a technique which lowers the freezing point of ice and hence the temperature) but this method could only be used on the relatively short trips from the USA to Europe. In 1925 American inventor and industrialist Clarence Birdseye came up with a method of freezing that did not rob food of its flavor. His method, called quick freezing operated on the premise that the faster the freezing, the less danger there was that ice crystals would rupture the cell walls of the food item. Some of the foods that Clarence Birdseye subjected to quick freezing were peas, spinach, rasberries, cherries, fish and meat. The development of refrigeration systems was greatly assisted by the introduction of reliable electric motors and public electricity supplies and the first domestic machines came on the market shortly after World War I, deep freeze units for home use being introduced in the mid 1930’s. The first refrigerator, as opposed to the simple ice box, designed for home use was the Domelre, which was manufactured in Chicago in 1913. A number of other competing machines quickly appeared, but in 1918 Kelvinator marketed a much more practical home refrigerator. Frigidaire followed with their model in 1919. In 1927, General Electric introduced a refrigerator with a “monitor top” containing a hermetically sealed compressor. U.S. electric refrigerator sales top 800,000 and the average price of a refrigerator falls to $292 in 1929. The first built-in refrigerator was launched by Electrolux in 1930. A compact product for the kitchenette in the small, modern apartments of the time. The next year they produced the first air-cooled refrigerator. The familiar dual temperature refrigerator is in use today, with one section for frozen food and a second for chilled food, was introduced into mass production by General Electric in 1939. During the 1940s frozen food storage became widely used by consumers. Refrigeration technology began hopping in the 1950s and ‘60s when innovations like automatic defrost and automatic ice makers first appeared. Life changed immensely in the 20th century as the refrigeration system became for efficient, controllable and even mobile. Refrigeration makes transporting fresh food and other perishables possible and makes home storage for days or weeks practical. By the end of the 20th century, 99.5 percent of U.S. households had at least one refrigerator. Many had separate freezers. People were able to simplify shopping and save money while enjoying a greater diversity and higher quality of food because of the excellent preservation technology. The main reason we have electric refrigeration today is because of the Research, Development and marketing investments of General Motors, General Electric, Kelvinator, and Westinghouse. These corporations, large at the time and some larger today, decided that the electric refrigerator offered a greater profit potential. There just was not as much money to be made in producing gas refrigerators. They devoted huge sums of money into both research and development and promotion of the electric refrigerator. New at the time, television advertisements depicted the electric refrigerator as modern, efficient, clean and safe. The smaller companies producing and marketing the gas refrigerator simply could not compete. In the 1970's, the gas refrigerator made a partial comeback as the best alternative for trailers, boats, hotels, offices, and mini-bars. The fundamental reason for having a refrigerator is to keep food cold. Cold temperatures help food stay fresh longer. The basic idea behind refrigeration is to slow down the activity of bacteria (which all food contains) so that it takes longer for the bacteria to spoil the food. For example, bacteria will spoil milk in two or three hours if the milk is left out on the kitchen counter at room temperature. However, by reducing the temperatures of the milk, it will stay fresh for a week or two. The cold temperatures inside the refrigerator decrease the activity of the bacteria that much. By freezing the milk you can stop the bacteria altogether, and the milk can last for months (until effects like freezer burn begin to spoil the milk in non-bacterial ways). Refrigeration and freezing are two most common forms of food preservation used today. In the kitchen of nearly every home in America there is a refrigerator. Every 15 minutes or so you hear the motor turn on, and it magically keeps things cold. Without refrigeration, we’d be throwing out our leftovers instead of saving them for another meal. The refrigerator is one of those miracles of modern living that totally changes the life of every consumer. Prior to refrigeration, the only way to preserve meat was to salt it, and iced beverages in the summer were a real luxury. Now, the fridge is one of the most common home appliances in everyone’s home. Bunch, Bryan and Alexander Hellemans. The Timetables of Technology: A Chronology of the Most Important People and Events in the History of Technology. New York: Simon & Simon, 1993. Donald Clarke, Mark Dartford, How it works: The illustrated Encyclopedia of Science and Technology, Volume 15, Marshall Cavendish Inc / January 1977. “The History of the Refrigerator (including Freezers)” http://inventors.about.com/library/inventors/blrefrigerator.htm (2 September 2001). “History of the Refrigerator” http://www2.whirlpool.com/html/homelife/cookin/cookref5.htm (2 September 2001). “Eloctrolux Fridge Histroy” http://www.eletrolux.com/node218.asp (3 September 2001). Bibliography:

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