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  Refrigeration Commercial refrigeration Refrigeration isaprocessinwhichworkisdonetomoveheatfromonelocationtoanother. Theworkofheattrans-port is traditionally driven by mechanical work, but canalso be driven by heat, magnetism, electricity, laser, or other means. Refrigeration has many applications, in-cluding, but not limited to: household refrigerators, in-dustrial freezers, cryogenics, and air conditioning. Heat pumps may use the heat output of the refrigeration pro-cess, and also may be designed to be reversible, but areotherwise similar to refrigeration units.Refrigerationhashadalargeimpactonindustry,lifestyle,agriculture and settlement patterns. The idea of pre-serving food dates back to the ancient Roman and Chi-nese empires. However, refrigeration technology hasrapidly evolved in the last century, from ice harvestingto temperature-controlled rail cars. The introduction ofrefrigerated rail cars contributed to the westward expan-sion of the United States, allowing settlement in areasthat were not on main transport channels such as rivers,harbors, or valley trails. Settlements were also poppingup in infertile parts of the country, filled with new natu-ral resources. These new settlement patterns sparked thebuilding of large cities which are able to thrive in areasthat were otherwise thought to be unsustainable, such asHouston, Texas and Las Vegas, Nevada. In most devel-oped countries, cities are heavily dependent upon refrig-eration in supermarkets, in order to obtain their food fordaily consumption. The increase in food sources has ledtoalargerconcentrationofagriculturalsalescomingfroma smaller percentage of existing farms. Farms today havea much larger output per person in comparison to the late1800s. This has resulted in new food sources available toentire populations, which has had a large impact on thenutrition of society. 1 History Main article: Timeline of low-temperature technology 1.1 Earliest forms of cooling The seasonal harvesting of snow and ice is an ancientpracticeestimatedtohavebegunearlierthan1000B.C. [1] A Chinese collection of lyrics from this time periodknown as the Shih king, describes religious ceremoniesfor filling and emptying ice cellars. However, little isknown about the construction of these ice cellars or whatthe ice was used for. The next ancient society to har-vest ice may have been the Jews according to the book ofProverbs, which reads, “As the cold of snow in the timeof harvest, so is a faithful messenger to them who senthim.” Historians have interpreted this to mean that theJews used ice to cool beverages rather than to preservefood. Other ancient cultures such as the Greeks and theRomans dug large snow pits insulated with grass, chaff,or branches of trees as cold storage. Like the Jews, theGreeks and Romans did not use ice and snow to preservefood, but primarily as a means to cool beverages. TheEgyptians also developed methods to cool beverages, butin lieu of using ice to cool water, the Egyptians cooledwater by putting boiling water in shallow earthen jars andplacing them on the roofs of their houses at night. Slaveswould moisten the outside of the jars and the resultingevaporation would cool the water. The ancient people ofIndiausedthissameconcepttoproduceice. ThePersiansstored ice in a pit called a Yakhchal and may have beenthe first group of people to use cold storage to preservefood. In the Australian outback before a reliable electric-ity supply was available where the weather could be hotand dry, many farmers used a “Coolgardie safe”. Thisconsisted of a room with hessian “curtains” hanging fromthe ceiling soaked in water. The water would evaporateand thereby cool the hessian curtains and thereby the aircirculating in the room. This would allow many perish-ables such as fruit butter and cured meats to be kept thatwould normally spoil in the heat.  [2][3] 1.2 Ice harvesting Before 1830, few Americans used ice to refrigerate foodsdue to a lack of ice-storehouses and iceboxes. As thesetwo things became more widely available, individuals1  2  1 HISTORY  Ice harvesting in Massachusetts  , 1852, showing the railroad  line in the background, used to transport the ice. used axes and saws to harvest ice for their storehouses.This method proved to be difficult, dangerous, and cer-tainly did not resemble anything that could be duplicatedon a commercial scale. [4] Despite the difficulties of harvesting ice, Frederic Tudorthought that he could capitalize on this new commodityby harvesting ice in New England and shipping it to theCaribbean islands as well as the southern states. In thebeginning, Tudorlostthousandsofdollars, buteventuallyturned a profit as he constructed icehouses in Charleston,Virginia and in the Cuban port town of Havana. Theseicehouses as well as better insulated ships helped reduceice wastage from 66% to 8%. This efficiency gain influ-enced Tudor to expand his ice market to other towns withicehouses such as New Orleans and Savannah. This icemarket further expanded as harvesting ice became fasterand cheaper after one of Tudor’s suppliers, NathanielWyeth, invented a horse-drawn ice cutter in 1825. Thisinvention as well as Tudor’s success inspired others to getinvolved in the ice trade and the ice industry grew.Icebecameamass-marketcommoditybytheearly1830swith the price of ice dropping from six cents per poundto a half of a cent per pound. In New York City, ice con-sumption increased from 12,000 tons in 1843 to 100,000tonsin1856. Boston’sconsumptionleaptfrom6,000tonsto 85,000 tons during that same period. Ice harvestingcreated a “cooling culture” as majority of people usedice and iceboxes to store their dairy products, fish, meat,and even fruits and vegetables. These early cold storagepractices paved the way for many Americans to accepttherefrigerationtechnologythatwouldsoontakeoverthecountry. [5][6] 1.3 Refrigeration research The history of artificial refrigeration began when Scottishprofessor William Cullen designed a small refrigeratingmachine in 1755. Cullen used a pump to create a par-tial vacuum over a container of diethyl ether, which then boiled, absorbing heat from the surrounding air. [7] Theexperiment even created a small amount of ice, but hadno practical application at that time. William Cullen , the first to conduct experiments into artificial re- frigeration. In 1758, Benjamin Franklin and John Hadley, professor of chemistry, collaborated on a project investigating theprinciple of evaporation as a means to rapidly cool an ob-ject at Cambridge University, England. They confirmed that the evaporation of highly volatile liquids, such as al-cohol and ether, could be used to drive down the temper-ature of an object past the freezing point of water. Theyconducted their experiment with the bulb of a mercurythermometer as their object and with a bellows used to“quicken” the evaporation; they lowered the temperatureofthethermometerbulbdownto7°F(−14°C),whiletheambient temperature was 65 °F (18 °C). They noted thatsoonaftertheypassedthefreezingpointofwater(32°F),a thin film of ice formed on the surface of the thermome-ter’s bulb and that the ice mass was about a quarter inchthick when they stopped the experiment upon reaching7 °F (−14 °C). Franklin wrote, “From this experiment,one may see the possibility of freezing a man to deathon a warm summer’s day”. [8] In 1805, American inventorOliver Evans described a closed vapor-compression re-frigeration cycle for the production of ice by ether undervacuum.In 1820, the British scientist Michael Faraday liquefiedammonia and other gases by using high pressures andlow temperatures, and in 1834, an American expatriateto Great Britain, Jacob Perkins, built the first workingvapor-compression refrigeration system in the world. Itwas a closed-cycle that could operate continuously, as hedescribed in his patent:I am enabled to use volatile fluids for the pur-pose of producing the cooling or freezing of  1.4 Commercial use  3fluids, and yet at the same time constantly con-densing such volatile fluids, and bringing themagain into operation without waste.His prototype system worked although it did not succeedcommercially. [9] In 1842, a similar attempt was made by American physi-cian, John Gorrie, [10] who built a working prototype, butit was a commercial failure. Like many of the medicalexperts during this time, Gorrie thought too much expo-sure to tropical heat led to mental and physical degenera-tion, as well as the spread of diseases such as malaria. [11] He conceived the idea of using his refrigeration system tocool the air for comfort in homes and hospitals to preventdisease. American engineer Alexander Twining took outa British patent in 1850 for a vapour compression systemthat used ether.Thefirstpracticalvaporcompressionrefrigerationsystemwas built by James Harrison, a British journalist who hademigrated to Australia. His 1856 patent was for a vapourcompression system using ether, alcohol or ammonia. Hebuilt a mechanical ice-making machine in 1851 on thebanks of the Barwon River at Rocky Point in Geelong,Victoria, and his first commercial ice-making machinefollowed in 1854. Harrison also introduced commercialvapour-compression refrigeration to breweries and meatpackinghouses, andby1861, adozenofhissystemswerein operation. He later entered the debate of how to com-pete against the American advantage of unrefrigeratedbeef sales to the United Kingdom. In 1873 he prepared the sailing ship  Norfolk   for an experimental beef ship-ment to the United Kingdom, which used a cold roomsystem instead of a refrigeration system. The venture wasa failure as the ice was consumed faster than expected. Ferdinand Carré 's ice-making device The first gas absorption refrigeration system usinggaseous ammonia dissolved in water (referred to as “aquaammonia”) was developed by Ferdinand Carré of Francein 1859 and patented in 1860. Carl von Linde, an engi-neer specializing in steam locomotives and professor ofengineering at the Technological University of Munichin Germany, began researching refrigeration in the 1860sand 70s in response to demand from brewers for a tech-nology that would allow year-round, large-scale produc-tion of lager; he patented an improved method of lique-fying gases in 1876. [12] His new process made possibleusing gases such as ammonia, sulfur dioxide (SO 2 ) andmethyl chloride (CH 3 Cl) as refrigerants and they werewidely used for that purpose until the late 1920s.Thaddeus Lowe, an American balloonist, held severalpatents on ice-making machines. His “Compression IceMachine” would revolutionize the cold-storage indus-try. In 1869, other investors and he purchased an oldsteamship onto which they loaded one of Lowe’s refriger-ation units and began shipping fresh fruit from New Yorkto the Gulf Coast area, and fresh meat from Galveston,Texas back to New York, but because of Lowe’s lack ofknowledge about shipping, the business was a costly fail-ure. 1.4 Commercial use See also: RefrigeratorIn 1842, John Gorrie created a system capable of refrig- An 1870 refrigerator car design. Hatches in the roof provided access to the tanks for the storage of harvested ice at each end. erating water to produce ice. Although it was a commer-cial failure, it inspired scientists and inventors around ofthe world. France’s Ferdinand Carre was one of the in-spired and he created an ice producing system that wassimpler and smaller than that of Gorrie. During the CivilWar, cities such as New Orleans could no longer get icefrom New England via the coastal ice trade. Carre’s re-frigeration system became the solution to New Orleansice problems and by 1865 the city had three of Carre’smachines. [13] In 1867, in San Antonio, Texas, a Frenchimmigrant named Andrew Muhl built an ice-making ma-chine to help service the expanding beef industry beforemoving it to Waco in 1871. In 1873, the patent for thismachine was contracted by the Columbus Iron Works, acompany acquired by the W. C. Bradley Co., which wenton to produce the first commercial ice-makers in the US.By the 1870s, breweries had become the largest users ofharvested ice. Though the ice-harvesting industry hadgrown immensely by the turn of the 20th century, pol-lution and sewage had begun to creep into natural ice,making it a problem in the metropolitan suburbs. Even-tually, breweries began to complain of tainted ice. Pub-lic concern for the purity of water, from which ice wasformed, began to increase in the early 1900s with the riseof germ theory. Numerous media outlets published arti-  4  1 HISTORY  cles connecting diseases such as typhoid fever with nat-ural ice consumption. This caused ice harvesting to be-come illegal in certain areas of the country. All of thesescenariosincreasedthedemandsformodernrefrigerationand manufactured ice. Ice producing machines like thatofCarre’sandMuhl’swerelookedtoasmeansofproduc-ing ice to meet the needs of grocers, farmers, and foodshippers. [14][15] Refrigerated railroad cars were introduced in the USin the 1840s for short-run transport of dairy prod-ucts, but these used harvested ice to maintain a cooltemperature. [16] Dunedin  , the first commercially successful refrigerated ship. The new refrigerating technology first met withwidespread industrial use as a means to freeze meatsupplies for transport by sea from the British Dominions and other countries to the British Isles. The first toachieve this breakthrough was an entrepreneur who hademigrated to New Zealand. William Soltau Davidson thought that Britain’s rising population and meat demandcould mitigate the slump in world wool markets that washeavily affecting New Zealand. After extensive research,he commissioned the  Dunedin  to be refitted with a com-pression refrigeration unit for meat shipment in 1881.On February 15, 1882, the  Dunedin  sailed for Londonwith what was to be the first commercially successfulrefrigerated shipping voyage, and the foundation of therefrigerated meat industry. [17] The Times   commented “Today we have to record such atriumph over physical difficulties, as would have been in-credible, even unimaginable, a very few days ago...”. The Marlborough —sister ship to the  Dunedin  – was imme-diately converted and joined the trade the following year,alongwiththerivalNewZealandShippingCompanyves-sel  Mataurua , while the German Steamer  Marsala  begancarrying frozen New Zealand lamb in December 1882.Withinfiveyears,172shipmentsoffrozenmeatweresentfromNew Zealandto theUnited Kingdom, ofwhichonly9 had significant amounts of meat condemned. Refriger-atedshippingalsoledtoabroadermeatanddairyboominAustralasia and South America. J & E Hall of Dartford, England outfitted the 'SS Selembria' with a vapor com-pressionsystemtobring30,000carcassesofmuttonfromthe Falkland Islands in 1886. [18] In the years ahead, theindustryrapidlyexpandedtoAustralia, Argentinaandthe United States.By the 1890s, refrigeration played a vital role in thedistribution of food. The meat packing industry re-lied heavily on natural ice in the 1880s and continuedto rely on manufactured ice as those technologies be-came available. [19] By 1900, the meat packing houses ofChicago had adopted ammonia-cycle commercial refrig-eration. By 1914, almost every location used artificialrefrigeration. The big meat packers, Armour, Swift, andWilson, had purchased the most expensive units whichthey installed on train cars and in branch houses and stor-age facilities in the more remote distribution areas.By the middle of the 20th century, refrigeration unitswere designed for installation on trucks or lorries.Refrigerated vehicles are used to transport perishablegoods, such as frozen foods, fruit and vegetables, andtemperature-sensitive chemicals. Most modern refrig-erators keep the temperature between  − 40 and 20 °C,and have a maximum payload of around 24,000 kg grossweight (in Europe).Although commercial refrigeration quickly progressed,it had limitations that prevented it from moving intothe household. First, most refrigerators were far toolarge. Some of the commercial units being used in 1910weighed between five and two hundred tons. Second,commercialrefrigeratorswereexpensivetoproduce, pur-chase, and maintain. Lastly, these refrigerators were un-safe. It was not uncommon for commercial refrigeratorsto catch fire, explode, or leak toxic gases. Refrigerationdid not become a household technology until these threechallenges were overcome. [20] 1.5 Home and consumer use During the early 1800s, consumers preserved their foodby storing food and ice purchased from ice harvesters iniceboxes. In1803, ThomasMoorepatentedametal-linedbutter-storage tub which became the prototype for mosticeboxes. Theseiceboxeswereuseduntilnearly1910andthe technology did not progress. In fact, consumers thatused the icebox in 1910 faced the same challenge of amoldy and stinky icebox that consumers had in the early1800s. [21] General Electric (GE) was one of the first companiesto overcome these challenges. In 1911, GE released ahousehold refrigeration unit that was powered by gas.The use of gas eliminated the need for motor and de-creased the size of the refrigerator. However, electriccompanies that were customers of GE did not benefitfrom a gas-powered unit. Thus, GE invested in develop-ing an electric model. In 1927, GE released the MonitorTop, the first refrigerator to run off electricity. [22] In 1930, Frigidaire, one of GE’s main competitors, syn-

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