Inventors.about.com describes refrigeration
as "the process of removing heat from an enclosed space, or from a substance,
to lower its temperature."5
ANTECEDENTS
- FOOD PRESERVATION TECHNIQUES - Cultures all over the world use many different techniques to preserve food. Salting, smoking, canning, preserves, pickling, and dry storage in pots are just a few examples of the many ways people preserved food before the popularization of the refrigerator. These techniques do not use any means of cooling to preserve foods.
- CELLARS - Throughout most of history, people used undergroud cellars to preserve foods. According to James Dyson, underground cellars were lined with "natural insulation such as straw" and stored ice and snow. Cellars were mostly effective in that they usually preserved food year round.6
- ICE HOUSES - After harvesting ice from cold regions
of the country, towns stored their ice in ice houses. These ice houses
protected all types of foods, but mostly meat.
- ICE BOXES - Ice boxes preserve foods in homes
as opposed to outdoor refrigeration seen in ice houses and cellars. Ice in
the ice boxes had to be replaced daily and the water pan empltied constantly.
One major reason why refrigerators were widely accepted was because other food preservation techniques significantly altered foods. Sue Shepard states that not only did they change the taste, but "many of the vitamins and other nutrients were destroyed or lost as a result of the long and severe treatment foods underwent ..."7 The refrigerator became successful because it did not change the taste or deplete vitamins and nutrients while preserving foods.
According to the History Channel, another contributing factor to the popularization and demand of refrigerators was the "Warm winters in 1889 and 1890" that "created severe shortages of natural ice in the U.S. This stimulated the sue of mechanical refrigeration for the freezing and storage of fish and in the brewing, dairy, and meat packing industries."8 People realized that they could no longer rely on underground cellars, ice houses, and ice boxes to adequately preserve their foods.
All of this created the demand to develop a form of artificial refrigeration. The first experiments in artificial refrigeration were conducted in 1748 by Dr. William Cullen who did the first known artificial refrigeration demonstration.9 In 1805, Oliver Evans, an American, designed the first refrigeration machine. According to John Oliver, in 1850, by using Evans' design, John Gorrie invented a machine that produced ice which he used "to cool the air for his yellow fever patients."10 In the early 1800s, Michael Faraday discovered that liquifying ammonia causes cooling.11 All of these major innovations to artificial refrigeration led to the invent of the first practical refrigeration unit.
THE REFRIGERATOR
In 1834, Jacob Perkins, an American, invented the refrigerator in London. Edward DeBono writes, "In his British Patent Specification of 1834 he described the vapour compression cycle, in which cooling was produced by the evaporation of volatile fluids."12 Inventors.about.com describes the process of refrigeration as:
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. It's all based on the following physics: - a liquid is rapidly vaporized (through compressions) - the quickly expanding vapor requires kinetic energy and draws the energy needed from the immediate area - which loses enrgy and becomes cooler. 13These earlier refrigerators used toxic gasses such as ammonia to create a cooling effect. Because these gasses were lethal if inhaled, many comsumers died as a result of them. To remedy the problems of toxic gasses, freon was invented in the 1930s.14 Freon became the most popular form of coolant until the 1990s when legislation was passed banning the use. Trevor Willimas states that in the 1920s, the most popular refrigerators sold were the Frigidaire and the Kelvinator because they "employed an electric motor to drive the compressor."15 The mass production of refrigerators began in the 1940s after World War II.16 This created a massive market where companies such as GE and Frigidaire could supply refrigerators to the masses.
Refrigerators were first made of a wood cabinet and a water-cooled compressor. According to the History Channel, beginning in the 1920s, "steel and porcelain cabinets" emerged to replace the less effective wood cabinets. 17 Throughout the 1950s and '60s, household refrigerators were improved to better suit consumers. The History Channel states that additions to the refrigerator such as "automatic defrost and automatic ice makers" were created to make refrigerators easier to use and required less maintenance. Modern advances in technology have improved the refrigerator to become more environmentally friendly. According to the History Channel, today, refrigerators are "more energy efficient."18 Many different styles of refrigerators have emerged. They now dispense water and ice right on the refrigerator door. With future technological advances, the refrigerator will continue to be improved to make life more easier.
IMPACT