Friday, August 11, 2017

The History of the Refrigerator.

Snow and ice, cool streams, springs, caves and cellars were long ago used to refrigerate food. Meat and fish were preserved in warm weather by salting or smoking.

The Chinese cut and stored ice in 1,000 B.C.

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 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.


At the beginning of the 19th century, ice boxes were used in England

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.

Wooden boxes lined with tin or zinc and insulated with various materials including cork, sawdust, and seaweed were used to hold blocks of ice and "refrigerate" food. A drip pan collected the melt water - and had to be emptied daily.

Pioneers in refrigeration included Dr. William Cullen, a Scotsman whose studies in the early 1700s dealt with the evaporation of liquids in a vacuum. Michael Farady, a Londoner who in the early 1800s liquified ammonia to cause cooling, and Dr. John Goorie of Apalachicola, Florida, who built a machine to make ice to cool the air for yellow fever patients in 1834. Today's compression refrigeration system operates on a concept adapted from Farady's experiments. It involves compressing gas into a liquid which will then absorb heat. In so doing it returns to gas. This is a simplified description of what happens in a home refrigerator, freezer, air conditioner or dehumidifier.

Artificial refrigeration began in the mid-1750s, and developed in the early 1800s. In 1834, the first working vapor-compression refrigeration system was built. The first commercial ice-making machine was invented in 1854. In 1913, refrigerators for home use were invented.

William Cullen at the University of Glasgow demonstrated the first artificial refrigeration system in the year 1748. However, he never used his discovery for practical purposes. In the year 1805, US inventor Oliver Evans, designed the first refrigeration machine that didn't use liquid and instead used vapor to cool.

The first known artificial form of refrigeration was demonstrated by William Cullen at the University of Glasgow in 1748. However, he did not use his discovery for any practical purpose. In 1805, an American inventor, Oliver Evans, designed the first refrigeration machine.

In 1834, the first working vapor-compression refrigeration system was built. The first commercial ice-making machine was invented in 1854. In 1913, refrigerators for home use were invented. In 1923 Frigidaire introduced the first self-contained unit.

Who invented the refrigeration cycle?

In 1805, American inventor Oliver Evans described a closed vapor-compression refrigeration cycle for the production of ice by ether under vacuum.

Warm winters in 1889 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. Commercial refrigeration techniques were also applied to railroad cars, were used in "coolers" in grocery stores and in various ways in manufacturing industries.

Two of the first home refrigerators both appeared in Fort Wayne, Indiana, where, in 1911, General Electric company unveiled a unit invented by a French monk. In 1915 the first "Guardian" refrigerator - a predecessor of the Frigidaire - was assembled in a wash house in a Fort Wayne backyard.

Kelvinator and Servel models were among some two dozen home refrigerators introduced to the U.S. market in 1916. In 1920 the number had increased to more than 200. Compressors were generally driven by belts attached to motors located in the basement or in an adjoining room.

In 1918 Kelvinator introduced the first refrigerator with any type of automatic control. One manufacturer's 1922 model had a wooden cabinet, a water-cooled compressor, two ice cube trays and nine cubic feet of storage space. It cost $714. In 1923 Frigidaire introduced the first self-contained unit. Steel and porcelain cabinets began appearing in the mid-20s.

In the 1920s and '30s, consumers were introduced to freezers when the first electric refrigerators with ice cube compartments came on the market. Mass production of modern refrigerators didn't get started until after World War II.

In the 1930s freon 12 was used to replace sulphur dioxide as the most commonly used refrigerant.

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.

The environment became a top priority in the 1970s and '80s, which lead to more energy-efficient refrigerators and elimination of chlorofluorocarbons in refrigeration sealed systems.

Today, the refrigerator is America's most used appliance, found in more than 99.5% of American homes.

Refrigeration is the process of creating cooling conditions by removing heat. It is mostly used to preserve food and other perishable items, preventing foodborne illnesses. It works because bacteria growth is slowed at lower temperatures.

Methods for preserving food by cooling have been around for thousands of years, but the modern refrigerator is a recent invention. Today, the demand for refrigeration and air conditioning represent nearly 20 percent of energy consumption worldwide, according to a 2015 article in the International Journal of Refrigeration.


The Chinese cut and stored ice around 1000 B.C., and 500 years later, the Egyptians and Indians learned to leave earthenware pots out during cold nights to make ice, according to Keep It Cool, a heating and cooling company based in Lake Park, Florida. Other civilizations, such as the Greeks, Romans and Hebrews, stored snow in pits and covered them with various insulating materials, according to History magazine. In various places in Europe during the 17th century, saltpeter dissolved in water was found to create cooling conditions and was used to create ice. In the 18th century, Europeans collected ice in the winter, salted it, wrapped it in flannel, and stored it underground where it kept for months. Ice was even shipped to other locations around the world, according to a 2004 article published in the journal of the American Society of Heating, Refrigeration, and Air-Conditioning Engineers (ASHRAE).

When ice wasn't available or practical, people used cool cellars or placed goods underwater, according to History magazine. Others built their own ice boxes, according to Keep It Cool. Wooden boxes were lined with tin or zinc and an insulating material such as cork, sawdust, or seaweed and filled with snow or ice. 

Evaporative cooling

The concept of mechanical refrigeration began when William Cullen, a Scottish doctor, observed that evaporation had a cooling effect in the 1720s. He demonstrated his ideas in 1748 by evaporating ethyl ether in a vacuum, according to Peak Mechanical Partnership, a plumbing and heating company based in Saskatoon, Saskatchewan. 

Oliver Evans, an American inventor, designed but did not build a refrigeration machine that used vapor instead of liquid in 1805. In 1820, English scientist Michael Faraday used liquefied ammonia to cause cooling. 

Jacob Perkins, who worked with Evans, received a patent for a vapor-compression cycle using liquid ammonia in 1835, according to History of Refrigeration. For that, he is sometimes called the "father of the refrigerator."

John Gorrie, an America doctor, also built a machine similar to Evans' design in 1842. Gorrie used his refrigerator, which created ice, to cool down patients with yellow fever in a Florida hospital. Gorrie received the first U.S. patent for his method of artificially creating ice in 1851.

Other inventors around the world continued to develop new and improve existing techniques for refrigeration, according to Peak Mechanical, including:

Ferdinand Carré, a French engineer, developed a refrigerator that used a mixture containing ammonia and water in 1859.
Carl von Linde, a German scientist, invented a portable compressor refrigeration machine using methyl ether in 1873, and in 1876 switched to ammonia. In 1894, Linde also developed new methods for liquefying large amounts of air.
Albert T. Marshall, an American inventor, patented the first mechanical refrigerator in 1899.
Renowned physicist Albert Einstein patented a refrigerator in 1930 with the idea of creating an environmentally friendly refrigerator with no moving parts and did not rely on electricity. 
The popularity of commercial refrigeration grew toward the end of the 19th century due to breweries, according to Peak Mechanical, where the first refrigerator was installed at a brewery in Brooklyn, New York, in 1870. By the turn of the century, nearly all breweries had a refrigerator.

The meatpacking industry followed with the first refrigerator introduced in Chicago in 1900, according to History magazine, and almost 15 years later, nearly all meatpacking plants used refrigerators.

Refrigerators were considered essential in homes by the 1920s, according to History magazine, and more than 90 percent of American homes had a refrigerator.

Today, nearly all homes in the United States — 99 percent — have at least one refrigerator, and about 26 percent of U.S. homes have more than one, according to a 2009 report by the U.S. Department of Energy.

How does a refrigerator work?

Refrigerators today work very similarly to refrigerators over a hundred years ago: by evaporating liquids, according to SciTech. Refrigerants, the liquid chemicals that are used to cool, evaporate at low temperatures. 

The liquids are pushed through the refrigerator through tubes and begin to vaporize. As the liquids evaporate, they carry heat away with them as the gases travel to a coil on the outside of the refrigerator, where the heat is released. The gases are returned to a compressor, where they become liquid again, and the cycle repeats.

Refrigerator safety

Early refrigerators used liquids and gases that were flammable, toxic, highly reactive or a combination, according to the U.S. Environmental Protection Agency (EPA). Thomas Midgley, an American engineer and chemist, researched safer options in 1926 and found that compounds containing fluorides appeared to be a great deal safer. Chlorofluorocarbons (CFCs), marketed by DuPont as Freon, grew in popularity, until the compounds were found to be harmful to the ozone layer in the atmosphere nearly 50 years later.

Most of the refrigerators manufactured today use hydrofluorocarbons (HFCs), according to the California Energy Commission, which are safer than CFCs and many other options, but still not the most ideal. The EPA keeps an updated list of acceptable materials that can be used in refrigerators as a coolant.

Refrigerators keep food safe, but only if operating at proper temperatures, according to the U.S. Food and Drug Administration. When refrigerators aren't kept cold enough, harmful bacteria within perishable foods grow rapidly and can contaminate the food, causing mild irritations to severe food poisoning if it is eaten. The FDA recommends that a refrigerator's temperature be set at a maximum of 40 degrees Fahrenheit (4.4 degrees Celsius); also, the refrigerator should not be not overly packed, and spills should be promptly cleaned.

Refrigerators of the future

New technologies in refrigeration include solid-state refrigerators and refrigerators that use magnets.

Traditionally, refrigerators have relied on large compressors, which generate a lot of heat and can easily heat up a room, said Tony Atti, CEO of Phononic, an electronics manufacturer based in Durham, North Carolina. The company gets its name from the theory of phonons, quantum particles that carry heat. 

Solid-state refrigerators use the entire surface of the refrigerator to very slowly and deliberately dissipate the heat so that an increase in temperature of the room is practically nonexistent and the surface of the refrigerator is cool to the touch, Atti told Live Science. These refrigerators also have the benefit of being free from harmful materials and loud operations, as well as being more accurately controlled. 

Another new type of refrigerator uses magnets to provide a vibration-free, silent, environmentally friendly refrigerator. Built by Haier in conjunction with BASF and Astronautics, the magnetic refrigerator uses a concept based on the magnetocaloric effect, discovered in 1917 by Pierre Weiss and Auguste Piccard, French and Swiss physicists respectively, according to an article by Andrej Kitanovski, et al., a group of scientists from Slovenia and Denmark, in 2015 and published by Springer International Publishing.

According to a press release on PR Newswire, proper red wine storage has very specific needs in order to maintain the taste and quality. The Haier refrigerator uses magnetocaloric heat pump (using a material that heats up in a magnetic field and cools down when it is not) with a water-based coolant, according to a news release on BASF, which relies on abundant and affordable raw materials. The magnetic refrigerator also uses up to 35 percent less power than traditional refrigerators.

Einstein's green refrigerator making a comeback

Einstein Refrigerator

In 1930, Einstein and Leo Szilard designed a refrigerator that required no electricity and had no moving parts.

While almost everybody knows how Einstein revolutionized physics with his theories of relativity, many people may not know that the great scientist had a domestic side, too. Well, sort of - in 1930, Einstein and his former student Leo Szilard designed a refrigerator that required no electricity and had no moving parts. However, as refrigerator technology became more efficient, Einstein's design was nearly forgotten.

Now, Malcolm McCulloch, an electrical engineer at Oxford, is trying to bring Einstein's refrigerator back. McCulloch explains that the design is environmentally friendly and could prove especially useful in developing countries, where demand for cooling appliances is quickly increasing.

McCulloch's team has recently built a prototype of Einstein and Szilard's refrigerator. Instead of compressing man-made greenhouse gases called freons, as typical refrigerators do, the prototype uses pressurized gas to keep items cold. The refrigerator just requires a way to heat the liquids, and McCulloch has been working on developing a solar energy system to meet this requirement.

The refrigerator is based on the idea that liquids boil at low temperatures when the surrounding air pressure is low.

"If you go to the top of Mount Everest, water boils at a much lower temperature than it does when you´re at sea level, and that´s because the pressure is much lower up there," McCulloch said.

In their refrigerator prototype, the scientists filled a flask with liquid butane (which is also commonly sold as a liquid in cigarette lighters and as a gas for cooking). Then the scientists introduced a new vapor to decrease the air pressure, which decreases the liquid boiling temperature, causing the butane to boil. As the butane boils, it takes energy from the surroundings, and lowers the temperature inside the refrigerator.

Although Einstein and Szilard´s original design was not as efficient as the freon refrigerators that replaced them, McCulloch plans to improve the design by using different kinds of gases. He predicts these improvements could quadruple the refrigerator´s efficiency.

The fact that the refrigerator has no moving parts could also be advantageous, he explains, as it would require minimal maintenance and so could be particularly useful in rural areas.

McCulloch emphasizes that the refrigerator is still just a prototype, but he hopes to one day commercialize it. The work is part of his team's three-year project to develop robust appliances that can be used in locations without electricity.

via: The Guardian

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