Array ( [0] => {{Short description|Process of moving heat from one location to another in controlled conditions}} [1] => [[File:Kuehlregal USA.jpg|thumb|Commercial refrigeration]] [2] => [3] => '''Refrigeration''' is any of various types of [[cooling]] of a space, substance, or system to lower and/or maintain its [[temperature]] below the ambient one (while the removed [[heat]] is ejected to a place of higher temperature).IIR International Dictionary of Refrigeration, http://dictionary.iifiir.org/search.php {{Webarchive|url=https://web.archive.org/web/20191001210219/http://dictionary.iifiir.org/search.php |date=2019-10-01 }}ASHRAE Terminology, https://www.ashrae.org/technical-resources/free-resources/ashrae-terminology Refrigeration is an artificial, or human-made, [[cooling]] method. [4] => [5] => Refrigeration refers to the process by which energy, in the form of heat, is removed from a low-temperature medium and transferred to a high-temperature medium.{{Cite book |last=Nehme |first=Charles |url=https://books.google.com/books?id=RiXHEAAAQBAJ&dq=%22Refrigeration+refers%22+to+the+process+by+which+energy,+in+the+form+of+heat,+is+removed+from+a+low-temperature+medium+and+transferred+to+a+high-temperature+medium&pg=PT2 |title=Refrigeration Fundamentals and Applications |publisher=Charles Nehme |language=en}}{{Cite book |last=Team |first=YCT Expert |url=https://books.google.com/books?id=4G_oEAAAQBAJ&dq=%22Refrigeration+refers%22+to+the+process+by+which+energy,+in+the+form+of+heat,+is+removed+from+a+low-temperature+medium+and+transferred+to+a+high-temperature+medium&pg=PA14 |title=2024-25 RRB/DRDO/ISRO Refrigeration & Air Conditioning Solved Papers |publisher=Youth Competition Times |pages=14 |language=en}} This work of energy transfer is traditionally driven by [[work (physics)|mechanical]] means (whether [[ice]] or [[electromechanics|electromechanical]] machines), but it can also be driven by heat, [[magnetism]], [[electricity]], [[laser cooling|laser]], or other means. Refrigeration has many applications, including household [[refrigerator]]s, industrial [[freezer]]s, [[cryogenics]], and [[air conditioning]].{{Cite web |title=Refrigeration Equipment Market Size And Forecast |url=https://refindustry.com/news/market-research/refrigeration-equipment-market-size-and-forecast/ |access-date=2024-03-12 |website=refindustry.com |language=en}}{{Cite web |title=Refrigerated storage - BEDES |url=https://bedes.lbl.gov/bedes-online/refrigerated-storage |access-date=2024-03-12 |website=refindustry.com |language=en}}{{Cite book |last=Gupta |first=Ajay Kumar |url=https://books.google.com/books?id=ODRcEAAAQBAJ&dq=Refrigeration+has+many+applications,+including+household+refrigerators,+industrial+freezers,+cryogenics,+and+air+conditioning.&pg=PT74 |title=The Complete Book on Cold Storage, Cold Chain & Warehouse 5th Edition |date=2022-02-02 |publisher=Niir Project Consultancy Services |isbn=978-81-955775-2-1 |language=en}} [[Heat pump]]s may use the heat output of the refrigeration process, and also may be designed to be reversible, but are otherwise similar to air conditioning units. [6] => [7] => Refrigeration has had a large impact on industry, lifestyle, agriculture, and settlement patterns.{{Cite book |last=Crawley |first=Gerard M. |url=https://books.google.com/books?id=tQUlEAAAQBAJ&dq=%22Refrigeration+has+had+a+large+impact+on+industry,+lifestyle,+agriculture,+and+settlement+patterns%22&pg=PA119 |title=Wind, Water And Fire: The Other Renewable Energy Resources |date=2021-02-25 |publisher=World Scientific |isbn=978-981-12-2593-2 |pages=119 |language=en}} The idea of preserving food dates back to human [[prehistory]], but for thousands of years humans were limited regarding the means of doing so. They used [[curing (food preservation)|curing]] via [[salting (food)|salting]] and [[food drying|drying]], and they made use of natural coolness in [[cave]]s, [[root cellar]]s, and [[winter]] weather, but other means of cooling were unavailable. In the 19th century, they began to make use of the [[ice trade]] to develop [[cold chain]]s.{{Cite book |last=Nehme |first=Charles |url=https://books.google.com/books?id=RiXHEAAAQBAJ&dq=%22In+the+19th+century,+they+began+to+make+use+of+the+ice+trade+to+develop+cold+chains%22&pg=PT2 |title=Refrigeration Fundamentals and Applications |publisher=Charles Nehme |language=en}} In the late 19th through mid-20th centuries, '''mechanical refrigeration''' was developed, improved, and greatly expanded in its reach. Refrigeration has thus rapidly evolved in the past century, from [[ice harvesting]] to [[Refrigerator car|temperature-controlled rail cars]], [[refrigerator truck]]s, and ubiquitous [[refrigerator]]s and [[freezer]]s in both stores and homes in many countries. The introduction of refrigerated rail cars contributed to the settlement of areas that were not on earlier main transport channels such as rivers, harbors, or valley trails. [8] => [9] => These new settlement patterns sparked the building of large cities which are able to thrive in areas that were otherwise thought to be inhospitable, such as [[Houston]], Texas, and [[Las Vegas]], Nevada. In most developed countries, cities are heavily dependent upon refrigeration in [[supermarket]]s in order to obtain their food for daily consumption.{{Cite book |last=Gupta |first=Ajay Kumar |url=https://books.google.com/books?id=ODRcEAAAQBAJ&dq=In+%22most+developed+countries%22,+cities+are+heavily+dependent+upon+refrigeration+in+supermarkets+in+order+to+obtain+their+food+for+daily+consumption&pg=PT74 |title=The Complete Book on Cold Storage, Cold Chain & Warehouse 5th Edition |date=2022-02-02 |publisher=Niir Project Consultancy Services |isbn=978-81-955775-2-1 |language=en}} The increase in food sources has led to a larger concentration of agricultural sales coming from a smaller percentage of farms.{{Cite book |last=Crawley |first=Gerard M. |url=https://books.google.com/books?id=tQUlEAAAQBAJ&dq=The+increase+in+food+sources+has+led+to+a+larger+concentration+of+agricultural+sales+coming+from+a+smaller+percentage+of+farms&pg=PA119 |title=Wind, Water And Fire: The Other Renewable Energy Resources |date=2021-02-25 |publisher=World Scientific |isbn=978-981-12-2593-2 |pages=119 |language=en}} Farms today have a much larger output per person in comparison to the late 1800s.{{Cite book |last=Review |first=The Princeton |url=https://books.google.com/books?id=hDq9EAAAQBAJ&dq=Farms+today+have+a+much+larger+output+per+person+in+comparison+to+the+late+1800s.&pg=PA304 |title=Princeton Review AP Human Geography Prep, 15th Edition: 3 Practice Tests + Complete Content Review + Strategies & Techniques |date=2023-10-24 |publisher=Random House Children's Books |isbn=978-0-593-51722-2 |pages=304 |language=en}} This has resulted in new food sources available to entire populations, which has had a large impact on the nutrition of society. [10] => [11] => ==History== [12] => {{For timeline|Timeline of low-temperature technology}} [13] => [14] => ===Earliest forms of cooling=== [15] => The seasonal harvesting of snow and ice is an ancient practice estimated to have begun earlier than 1000 BC.{{cite book|last=Neuburger|first=Albert|title=The technical arts and sciences of the ancients|year=2003|publisher=Kegan Paul|location=London|isbn=978-0-7103-0755-2|page=122}} A Chinese collection of lyrics from this time period known as the ''[[Sleaping]]'', describes religious ceremonies for filling and emptying ice cellars. However, little is known about the construction of these ice cellars or the purpose of the ice. The next ancient society to record the harvesting of ice may have been the Jews in the book of Proverbs, which reads, "As the cold of snow in the time of harvest, so is a faithful messenger to them who sent him." Historians have interpreted this to mean that the Jews used ice to cool beverages rather than to preserve food. Other ancient cultures such as the Greeks and the Romans dug large snow pits insulated with grass, chaff, or branches of trees as cold storage. Like the Jews, the Greeks and Romans did not use ice and snow to preserve food, but primarily as a means to cool beverages. Egyptians cooled water by evaporation in shallow earthen jars on the roofs of their houses at night. The ancient people of India used this same concept to produce ice. The Persians stored ice in a pit called a [[Yakhchal]] and may have been the first group of people to use cold storage to preserve food. In the Australian outback before a reliable electricity supply was available many farmers used a [[Coolgardie safe]], consisting of a room with [[hessian fabric|hessian]] (burlap) curtains hanging from the ceiling soaked in water. The water would evaporate and thereby cool the room, allowing many perishables such as fruit, butter, and cured meats to be kept.{{cite book|last=Neuburger|first=Albert|title=The technical arts and sciences of the ancients|year=2003|publisher=Kegan Paul|location=London|isbn=978-0-7103-0755-2|pages=122–124}}{{cite book|last=Anderson|first=Oscar Edward|title=Refrigeration in America; a history of a new technology and its impact|year=1953|publisher=Published for the University of Cincinnati by Princeton University Press|location=Princeton|isbn=978-0-8046-1621-8|pages=5–6}} [16] => [17] => ===Ice harvesting=== [18] => {{See also|Ice cutting|Ice trade}} [19] => [[File:Ice Harvesting, Massachusetts, early 1850s.jpg|thumb|Ice harvesting in [[Massachusetts]], 1852, showing the [[railroad]] line in the background, used to transport the ice.]] [20] => Before 1830, few Americans used ice to refrigerate foods due to a lack of ice-storehouses and iceboxes. As these two things became more widely available, individuals used axes and saws to [[ice cutting|harvest ice]] for their storehouses. This method proved to be difficult, dangerous, and certainly did not resemble anything that could be duplicated on a commercial scale.{{cite book|last=Anderson|first=Oscar Edward|title=Refrigeration in America; a history of a new technology and its impact|year=1953|publisher=Published for the University of Cincinnati by Princeton University Press|location=Princeton|isbn=978-0-8046-1621-8|pages=8–11}} [21] => [22] => Despite the difficulties of harvesting ice, Frederic Tudor thought that he could capitalize on this new commodity by harvesting ice in New England and shipping it to the Caribbean islands as well as the southern states. In the beginning, Tudor lost thousands of dollars, but eventually turned a profit as he constructed icehouses in Charleston, Virginia and in the Cuban port town of Havana. These icehouses as well as better insulated ships helped reduce ice wastage from 66% to 8%. This efficiency gain influenced Tudor to expand his ice market to other towns with icehouses such as New Orleans and Savannah. This ice market further expanded as harvesting ice became faster and cheaper after one of Tudor's suppliers, Nathaniel Wyeth, invented a horse-drawn ice cutter in 1825. This invention as well as Tudor's success inspired others to get involved in the [[ice trade]] and the ice industry grew. [23] => [24] => Ice became a mass-market commodity by the early 1830s with the price of ice dropping from six cents per pound to a half of a cent per pound. In New York City, ice consumption increased from 12,000 tons in 1843 to 100,000 tons in 1856. Boston's consumption leapt from 6,000 tons to 85,000 tons during that same period. Ice harvesting created a "cooling culture" as majority of people used ice and iceboxes to store their dairy products, fish, meat, and even fruits and vegetables. These early cold storage practices paved the way for many Americans to accept the refrigeration technology that would soon take over the country.{{cite book|last=Anderson|first=Oscar Edward|title=Refrigeration in America; a history of a new technology and its impact|year=1953|publisher=Published for the University of Cincinnati by Princeton University Press|location=Princeton|isbn=978-0-8046-1621-8|pages=11–13}}{{cite book|last=Freidberg|first=Susanne|title=Fresh: a perishable history|year=2010|publisher=Belknap|location=Cambridge, MA|isbn=978-0-674-05722-7|pages=20–23|edition=1st Harvard University Press pbk.}} [25] => [26] => ===Refrigeration research=== [27] => [[File:William Cullen.jpg|thumb|upright|[[William Cullen]], the first to conduct experiments into artificial refrigeration.]] [28] => The history of artificial refrigeration began when Scottish professor [[William Cullen]] designed a small refrigerating machine in 1755. Cullen used a pump to create a partial [[vacuum]] over a container of [[diethyl ether]], which then [[boiling point|boiled]], absorbing [[heat of vaporization|heat]] from the surrounding air.{{cite book|last=Arora|first=Ramesh Chandra|title=Refrigeration and Air Conditioning|publisher=PHI Learning|location=New Delhi|isbn=978-81-203-3915-6|page=3|chapter=Mechanical vapour compression refrigeration|year=2012}} The experiment even created a small amount of ice, but had no practical application at that time. [29] => [30] => In 1758, [[Benjamin Franklin]] and [[John Hadley (chemist)|John Hadley]], professor of chemistry, collaborated on a project investigating the principle of evaporation as a means to rapidly cool an object at [[Cambridge University]], [[England]]. They confirmed that the evaporation of highly volatile liquids, such as alcohol and ether, could be used to drive down the temperature of an object past the freezing point of water. They conducted their experiment with the bulb of a mercury thermometer as their object and with a bellows used to quicken the evaporation; they lowered the temperature of the thermometer bulb down to {{convert|7|°F|°C|abbr=on|order=flip}}, while the ambient temperature was {{convert|65|°F|°C|abbr=on|order=flip}}. They noted that soon after they passed the freezing point of water {{convert|0|°C|°F|abbr=on}}, a thin film of ice formed on the surface of the thermometer's bulb and that the ice mass was about a {{convert|1/4|in|mm|order=flip}} thick when they stopped the experiment upon reaching {{convert|7|°F|°C|abbr=on|order=flip}}. Franklin wrote, "From this experiment, one may see the possibility of freezing a man to death on a warm summer's day".[http://www.historycarper.com/resources/twobf3/letter1.htm Cooling by Evaporation (Letter to John Lining)] {{webarchive|url=https://web.archive.org/web/20110128075748/http://www.historycarper.com/resources/twobf3/letter1.htm |date=2011-01-28}}. Benjamin Franklin, London, June 17, 1758 In 1805, American inventor [[Oliver Evans]] described a closed [[vapor-compression refrigeration]] cycle for the production of ice by ether under vacuum. [31] => [32] => In 1820, the English scientist [[Michael Faraday]] liquefied [[ammonia]] and other gases by using high pressures and low temperatures, and in 1834, an American expatriate to Great Britain, [[Jacob Perkins]], built the first working vapor-compression refrigeration system in the world. It was a closed-cycle that could operate continuously, as he described in his patent: [33] => :I am enabled to use volatile fluids for the purpose of producing the cooling or freezing of fluids, and yet at the same time constantly condensing such volatile fluids, and bringing them again into operation without waste. [34] => [35] => His prototype system worked although it did not succeed commercially.{{cite book |last= Burstall |first= Aubrey F. |year= 1965 |title= A History of Mechanical Engineering |publisher=The MIT Press |isbn= 978-0-262-52001-0}} [36] => [37] => In 1842, a similar attempt was made by American physician, [[John Gorrie]],{{Cite web|url=https://pdfpiw.uspto.gov/.piw?Docid=00008080&homeurl=http%3A%2F%2Fpatft.uspto.gov%2Fnetacgi%2Fnph-Parser%3FSect1%3DPTO1%2526Sect2%3DHITOFF%2526d%3DPALL%2526p%3D1%2526u%3D%25252Fnetahtml%25252FPTO%25252Fsrchnum.htm%2526r%3D1%2526f%3DG%2526l%3D50%2526s1%3D0008080.PN.%2526OS%3DPN%2F0008080%2526RS%3DPN%2F0008080&PageNum=&Rtype=&SectionNum=&idkey=NONE&Input=View+first+page|title=Patent Images}} who built a working prototype, but it was a commercial failure. Like many of the medical experts during this time, Gorrie thought too much exposure to tropical heat led to mental and physical degeneration, as well as the spread of diseases such as malaria.{{cite book|last=Freidberg|first=Susanne|title=Fresh: a perishable history|year=2010|publisher=Belknap|location=Cambridge, MA|isbn=978-0-674-05722-7|pages=23|edition=1st Harvard University Press pbk.}} He conceived the idea of using his refrigeration system to cool the air for comfort in homes and hospitals to prevent disease. American engineer [[Alexander Twining]] took out a British patent in 1850 for a vapour compression system that used ether. [38] => [39] => The first practical vapour-compression refrigeration system was built by [[James Harrison (engineer)|James Harrison]], a British journalist who had emigrated to [[Australia]]. His 1856 patent was for a vapour-compression system using ether, alcohol, or ammonia. He built a mechanical ice-making machine in 1851 on the banks of the Barwon River at Rocky Point in [[Geelong]], [[Victoria (Australia)|Victoria]], and his first commercial ice-making machine followed in 1854. Harrison also introduced commercial vapour-compression refrigeration to breweries and meat-packing houses, and by 1861, a dozen of his systems were in operation. He later entered the debate of how to compete against the American advantage of unrefrigerated [[beef]] sales to the [[United Kingdom]]. In 1873 he prepared the sailing ship ''Norfolk'' for an experimental beef shipment to the United Kingdom, which used a cold room system instead of a refrigeration system. The venture was a failure as the ice was consumed faster than expected. [40] => [41] => [[File:AppareilCarré.jpg|thumb|left|[[Ferdinand Carré]]'s ice-making device]] [42] => The first [[absorption refrigeration|gas absorption]] refrigeration system using gaseous ammonia dissolved in water (referred to as "aqua ammonia") was developed by [[Ferdinand Carré]] of France in 1859 and patented in 1860. [[Carl von Linde]], an engineer specializing in [[steam locomotive]]s and professor of engineering at the [[Technische Universität München|Technological University of Munich]] in Germany, began researching refrigeration in the 1860s and 1870s in response to demand from brewers for a technology that would allow year-round, large-scale production of [[lager]]; he patented an improved method of liquefying gases in 1876.{{cite episode |title= Eat, Drink, and Be Merry |series= Connections |series-link=Connections (British documentary)|credits= [[James Burke (science historian)|James Burke]] |network=BBC |date=1979 |number= 8|minutes=41–49 |language=en}} His new process made possible using gases such as [[ammonia]], [[sulfur dioxide]] (SO2) and [[methyl chloride]] (CH3Cl) as refrigerants and they were widely used for that purpose until the late 1920s. [43] => [44] => [[Thaddeus Lowe]], an American balloonist, held several patents on ice-making machines. His "Compression Ice Machine" would revolutionize the cold-storage industry. In 1869, he and other investors purchased an old steamship onto which they loaded one of Lowe's refrigeration units and began shipping fresh fruit from New York to the Gulf Coast area, and fresh meat from Galveston, Texas back to New York, but because of Lowe's lack of knowledge about shipping, the business was a costly failure. [45] => [46] => ===Commercial use=== [47] => {{See also|Cold chain|Refrigerator}} [48] => [[File:Early refrigerator car design circa 1870.jpg|thumb|An 1870 refrigerator car design. Hatches in the roof provided access to the tanks for the storage of harvested ice at each end.|right]] [49] => [[File:AndrewMuhlPatent02.png|thumb|Icemaker Patent by Andrew Muhl, dated December 12, 1871.]] [50] => In 1842, [[John Gorrie]] created a system capable of refrigerating water to produce ice. Although it was a commercial failure, it inspired scientists and inventors around the world. France's Ferdinand Carre was one of the inspired and he created an ice producing system that was simpler and smaller than that of Gorrie. During the Civil War, cities such as New Orleans could no longer get ice from New England via the coastal ice trade. Carre's refrigeration system became the solution to New Orleans' ice problems and, by 1865, the city had three of Carre's machines.{{cite book|last=Anderson|first=Oscar Edward|title=Refrigeration in America; a history of a new technology and its impact|year=1953|publisher=Published for the University of Cincinnati by Princeton University Press|location=Princeton|isbn=978-0-8046-1621-8|pages=25}} In 1867, in San Antonio, Texas, a French immigrant named Andrew Muhl built an ice-making machine to help service the expanding beef industry before moving it to Waco in 1871. In 1873, the patent for this machine was contracted by the Columbus Iron Works, a company acquired by the W.C. Bradley Co., which went on to produce the first commercial ice-makers in the US. [51] => [52] => By the 1870s, breweries had become the largest users of harvested ice. Though the ice-harvesting industry had grown immensely by the turn of the 20th century, pollution and sewage had begun to creep into natural ice, making it a problem in the metropolitan suburbs. Eventually, breweries began to complain of tainted ice. Public concern for the purity of water, from which ice was formed, began to increase in the early 1900s with the rise of germ theory. Numerous media outlets published articles connecting diseases such as typhoid fever with natural ice consumption. This caused ice harvesting to become illegal in certain areas of the country. All of these scenarios increased the demands for modern refrigeration and manufactured ice. Ice producing machines like that of Carre's and Muhl's were looked to as means of producing ice to meet the needs of grocers, farmers, and food shippers.{{cite book|last=Freidberg|first=Susanne|title=Fresh: a perishable history|year=2010|publisher=Belknap|location=Cambridge, MA|isbn=978-0-674-05722-7|pages=25|edition=1st Harvard University Press pbk.}}{{cite book|last=Anderson|first=Oscar Edward|title=Refrigeration in America; a history of a new technology and its impact|year=1953|publisher=Published for the University of Cincinnati by Princeton University Press|location=Princeton|isbn=978-0-8046-1621-8|pages=110–111}} [53] => [54] => Refrigerated railroad cars were introduced in the US in the 1840s for short-run transport of dairy products, but these used harvested ice to maintain a cool temperature.[https://tshaonline.org/handbook/online/articles/dqr01 Refrigeration], Texas State Historical Association. [55] => [56] => [[File:SS Dunedin by Frederick Tudgay.JPG|thumb|left|[[Dunedin (ship)|''Dunedin'']], the first commercially successful refrigerated ship.]] [57] => The new refrigerating technology first met with widespread industrial use as a means to freeze meat supplies for transport by sea in [[reefer ship]]s from the British [[Dominion]]s and other countries to the [[British Isles]]. Although not actually the first to achieve successful transportation of frozen goods overseas (the ''Strathleven'' had arrived at the London docks on 2 February 1880 with a cargo of frozen beef, mutton and butter from Sydney and Melbourne {{cite book |last1=Munro |first1=J. Forbes |title=Maritime Enterprise and Empire : Sir William MacKinnon and his Business Network,1823-1893 |date=2003 |publisher=Boydell Press |isbn=9780851159355 |page=283 |url=https://books.google.com/books?id=Dm6tSiRizBcC&dq=may+2+1880+frozen+meat+melbourne&pg=PA283}}), the breakthrough is often attributed to [[William Soltau Davidson]], an entrepreneur who had emigrated to [[New Zealand]]. Davidson thought that Britain's rising population and meat demand could mitigate the slump in world [[wool]] markets that was heavily affecting New Zealand. After extensive research, he commissioned the [[Dunedin (ship)|''Dunedin'']] to be refitted with a compression refrigeration unit for meat shipment in 1881. On February 15, 1882, the ''Dunedin'' sailed for London with what was to be the first commercially successful refrigerated shipping voyage, and the foundation of the refrigerated [[meat industry]].{{cite book|title=A lasting Legacy – A 125 year history of New Zealand Farming since the first Frozen Meat Shipment|author=Colin Williscroft|publisher=NZ Rural Press Limited|year=2007|url=https://books.google.com/books?id=VTrmMQAACAAJ}} [58] => [59] => ''[[The Times]]'' commented "Today we have to record such a triumph over physical difficulties, as would have been incredible, even unimaginable, a very few days ago...". The ''[[Marlborough (1876 ship)|Marlborough]]''—sister ship to the ''Dunedin'' – was immediately converted and joined the trade the following year, along with the rival [[New Zealand Shipping Company]] vessel ''Mataurua'', while the German Steamer ''Marsala'' began carrying frozen New Zealand lamb in December 1882. Within five years, 172 shipments of frozen meat were sent from New Zealand to the United Kingdom, of which only 9 had significant amounts of meat condemned. Refrigerated shipping also led to a broader meat and dairy boom in [[Australasia]] and South America. [[J & E Hall]] of [[Dartford]], England outfitted the ''SS Selembria'' with a vapor compression system to bring 30,000 carcasses of [[mutton]] from the [[Falkland Islands]] in 1886.{{Cite web|url=http://www.jehall.com/about-jeh-group/history|title=Our History | Refrigeration Solutions | J&E Hall|website=www.jehall.com}} In the years ahead, the industry rapidly expanded to Australia, Argentina and the United States. [60] => [61] => By the 1890s, refrigeration played a vital role in the distribution of food. The meat-packing industry relied heavily on natural ice in the 1880s and continued to rely on manufactured ice as those technologies became available.{{cite book|last=Freidberg|first=Susanne|title=Fresh: a perishable history|year=2010|publisher=Belknap|location=Cambridge, MA|isbn=978-0-674-05722-7|pages=142|edition=1st Harvard University Press pbk.}} By 1900, the meat-packing houses of Chicago had adopted ammonia-cycle commercial refrigeration. By 1914, almost every location used artificial refrigeration. The [[Meat packing industry#Meatpackers|major meat packers]], Armour, Swift, and Wilson, had purchased the most expensive units which they installed on train cars and in branch houses and storage facilities in the more remote distribution areas. [62] => [63] => By the middle of the 20th century, refrigeration units were designed for installation on trucks or lorries. Refrigerated vehicles are used to transport perishable goods, such as frozen foods, fruit and vegetables, and temperature-sensitive chemicals. Most modern refrigerators keep the temperature between –40 and –20 °C, and have a maximum payload of around 24,000 kg gross weight (in Europe). [64] => [65] => Although commercial refrigeration quickly progressed, it had limitations that prevented it from moving into the household. First, most refrigerators were far too large. Some of the commercial units being used in 1910 weighed between five and two hundred tons. Second, commercial refrigerators were expensive to produce, purchase, and maintain. Lastly, these refrigerators were unsafe. It was not uncommon for commercial refrigerators to catch fire, explode, or leak toxic gases. Refrigeration did not become a household technology until these three challenges were overcome.{{cite book|last=Freidberg|first=Susanne|title=Fresh: a perishable history|year=2010|publisher=Belknap|location=Cambridge, MA|isbn=978-0-674-05722-7|pages=38|edition=1st Harvard University Press pbk.}} [66] => [67] => ===Home and consumer use=== [68] => [[File:Early household refrigerator in Popular Science 1919.png|thumb|An early example of the [[consumerization]] of mechanical refrigeration that began in the early 20th century. The [[refrigerant]] was [[sulfur dioxide]].]] [69] => [[File:Food into a refrigerator - 20111002.jpg|thumb|A modern home refrigerator]] [70] => [71] => During the early 1800s, consumers preserved their food by storing food and ice purchased from ice harvesters in iceboxes. In 1803, Thomas Moore patented a metal-lined butter-storage tub which became the prototype for most iceboxes. These iceboxes were used until nearly 1910 and the technology did not progress. In fact, consumers that used the icebox in 1910 faced the same challenge of a moldy and stinky icebox that consumers had in the early 1800s.{{cite book|last=Freidberg|first=Susanne|title=Fresh: a perishable history|year=2010|publisher=Belknap|location=Cambridge, MA|isbn=978-0-674-05722-7|pages=23, 38|edition=1st Harvard University Press pbk.}} [72] => [73] => General Electric (GE) was one of the first companies to overcome these challenges. In 1911, GE released a household refrigeration unit that was powered by gas. The use of gas eliminated the need for an electric compressor motor and decreased the size of the refrigerator. However, electric companies that were customers of GE did not benefit from a gas-powered unit. Thus, GE invested in developing an electric model. In 1927, GE released the Monitor Top, the first refrigerator to run on electricity.{{cite book|last=Freidberg|first=Susanne|title=Fresh: a perishable history|year=2010|publisher=Belknap|location=Cambridge, MA|isbn=978-0-674-05722-7|pages=43–45|edition=1st Harvard University Press pbk.}} [74] => [75] => In 1930, Frigidaire, one of GE's main competitors, synthesized [[Freon]].{{cite book|last=Freidberg|first=Susanne|title=Fresh: a perishable history|year=2010|publisher=Belknap|location=Cambridge, MA|isbn=978-0-674-05722-7|pages=44|edition=1st Harvard University Press pbk.}} With the invention of synthetic refrigerants based mostly on a chlorofluorocarbon (CFC) chemical, safer refrigerators were possible for home and consumer use. Freon led to the development of smaller, lighter, and cheaper refrigerators. The average price of a refrigerator dropped from $275 to $154 with the synthesis of Freon. This lower price allowed ownership of refrigerators in American households to exceed 50% by 1940.{{cite book|last=Freidberg|first=Susanne|title=Fresh: a perishable history|year=2010|publisher=Belknap|location=Cambridge, MA|isbn=978-0-674-05722-7|pages=45|edition=1st Harvard University Press pbk.}} Freon is a trademark of the DuPont Corporation and refers to these CFCs, and later hydro chlorofluorocarbon (HCFC) and hydro fluorocarbon (HFC), refrigerants developed in the late 1920s. These refrigerants were considered — at the time — to be less harmful than the commonly-used refrigerants of the time, including methyl formate, ammonia, methyl chloride, and sulfur dioxide. The intent was to provide refrigeration equipment for home use without danger. These CFC refrigerants answered that need. In the 1970s, though, the compounds were found to be reacting with atmospheric ozone, an important protection against solar ultraviolet radiation, and their use as a refrigerant worldwide was curtailed in the [[Montreal Protocol]] of 1987. [76] => [77] => ==Impact on settlement patterns in the United States of America== [78] => {{unreferenced section|date=February 2020}} [79] => [80] => In the last century, refrigeration allowed new settlement patterns to emerge. This new technology has allowed for new areas to be settled that are not on a natural channel of transport such as a river, valley trail or harbor that may have otherwise not been settled. Refrigeration has given opportunities to early settlers to expand westward and into rural areas that were unpopulated. These new settlers with rich and untapped soil saw opportunity to profit by sending raw goods to the eastern cities and states. In the 20th century, refrigeration has made "Galactic Cities" such as Dallas, Phoenix and Los Angeles possible. [81] => [82] => ===Refrigerated rail cars=== [83] => The refrigerated rail car ([[refrigerated van]] or [[refrigerator car]]), along with the dense railroad network, became an exceedingly important link between the marketplace and the farm allowing for a national opportunity rather than a just a regional one. Before the invention of the refrigerated rail car, it was impossible to ship perishable food products long distances. The beef packing industry made the first demand push for refrigeration cars. The railroad companies were slow to adopt this new invention because of their heavy investments in cattle cars, stockyards, and feedlots.{{cite journal|last=Danes-Wingett|first=Lind|title=The Ice Car Cometh: A History of the Refrigerated Rail Car|journal=The San Joaquin Historian|volume=10|issue=4|pages=2}} Refrigeration cars were also complex and costly compared to other rail cars, which also slowed the adoption of the refrigerated rail car. After the slow adoption of the refrigerated car, the beef packing industry dominated the refrigerated rail car business with their ability to control ice plants and the setting of icing fees. The United States Department of Agriculture estimated that, in 1916, over sixty-nine percent of the cattle killed in the country was done in plants involved in interstate trade. The same companies that were also involved in the meat trade later implemented refrigerated transport to include vegetables and fruit. The meat packing companies had much of the expensive machinery, such as refrigerated cars, and cold storage facilities that allowed for them to effectively distribute all types of perishable goods. During World War I, a national refrigerator car pool was established by the United States Administration to deal with problem of idle cars and was later continued after the war.{{cite journal|last=Danes-Wingett|first=Lind|title=The Ice Car Cometh: A History of the Refrigerated Rail Car|journal=The San Joaquin Historian|volume=10|issue=4}} The idle car problem was the problem of refrigeration cars sitting pointlessly in between seasonal harvests. This meant that very expensive cars sat in rail yards for a good portion of the year while making no revenue for the car's owner. The car pool was a system where cars were distributed to areas as crops matured ensuring maximum use of the cars. Refrigerated rail cars moved eastward from vineyards, orchards, fields, and gardens in western states to satisfy Americas consuming market in the east.{{cite journal|last=Danes-Wingett|first=Lind|title=The Ice Car Cometh: A History of the Refrigerated Rail Car|journal=The San Joaquin Historian|volume=10|issue=4|pages=3}} The refrigerated car made it possible to transport perishable crops hundreds and even thousands of kilometres or miles. The most noticeable effect the car gave was a regional specialization of vegetables and fruits. The refrigeration rail car was widely used for the transportation of perishable goods up until the 1950s. By the 1960s, the nation's interstate highway system was adequately complete allowing for trucks to carry the majority of the perishable food loads and to push out the old system of the refrigerated rail cars.{{cite journal|last=Stover|first=J.|title=American Railroads|url=https://archive.org/details/lifedeclineoft00stov|url-access=registration|journal=The Chicago History of the Railroad Refrigerator Car|year=1970|pages=[https://archive.org/details/lifedeclineoft00stov/page/214 214]}} [84] => [85] => ===Expansion west and into rural areas=== [86] => The widespread use of refrigeration allowed for a vast amount of new agricultural opportunities to open up in the United States. New markets emerged throughout the United States in areas that were previously uninhabited and far-removed from heavily populated areas. New agricultural opportunity presented itself in areas that were considered rural, such as states in the south and in the west. Shipments on a large scale from the south and California were both made around the same time, although natural ice was used from the Sierras in California rather than manufactured ice in the south.{{cite journal|last=Danes-Wingett|first=Lind|title=The Ice Car Cometh: A History of the Refrigerated Rail Car|journal=The San Joaquin Historian|volume=10|issue=4|pages=7}} Refrigeration allowed for many areas to specialize in the growing of specific fruits. California specialized in several fruits, grapes, peaches, pears, plums, and apples, while Georgia became famous for specifically its peaches. In California, the acceptance of the refrigerated rail cars led to an increase of car loads from 4,500 carloads in 1895 to between 8,000 and 10,000 carloads in 1905.{{cite book|last=Anderson|first=Oscar Edward|title=Refrigeration in America; a history of a new technology and its impact|year=1953|publisher=Published for the University of Cincinnati by Princeton University Press|location=Princeton|isbn=978-0-8046-1621-8|pages=156}} The Gulf States, Arkansas, Missouri and Tennessee entered into strawberry production on a large-scale while Mississippi became the center of the [[tomato industry]]. New Mexico, Colorado, Arizona, and Nevada grew cantaloupes. Without refrigeration, this would have not been possible. By 1917, well-established fruit and vegetable areas that were close to eastern markets felt the pressure of competition from these distant specialized centers.{{cite book|last=Anderson|first=Oscar Edward|title=Refrigeration in America; a history of a new technology and its impact|year=1953|publisher=Published for the University of Cincinnati by Princeton University Press|location=Princeton|isbn=978-0-8046-1621-8|pages=158}} Refrigeration was not limited to meat, fruit and vegetables but it also encompassed dairy product and dairy farms. In the early twentieth century, large cities got their dairy supply from farms as far as {{convert|400|mi|km|order=flip}}. Dairy products were not as easily transported over great distances like fruits and vegetables due to greater perishability. Refrigeration made production possible in the west far from eastern markets, so much in fact that dairy farmers could pay transportation cost and still undersell their eastern competitors.{{cite book|last=Anderson|first=Oscar Edward|title=Refrigeration in America; a history of a new technology and its impact|year=1953|publisher=Published for the University of Cincinnati by Princeton University Press|location=Princeton|isbn=978-0-8046-1621-8|pages=168}} Refrigeration and the refrigerated rail gave opportunity to areas with rich soil far from natural channel of transport such as a river, valley trail or harbors.{{cite web|last=Schimd|first=A.|title=The Economics of Population Settlement: Cost of Alternative Growth Patterns|url=http://www.soc.iastate.edu/Extension/ncrcrd/NCRCRD-rrd172-print.pdf |archive-url=https://web.archive.org/web/20100504154836/http://www.soc.iastate.edu/extension/ncrcrd/NCRCRD-rrd172-print.pdf |archive-date=2010-05-04 |url-status=live}} [87] => [88] => ===Rise of the galactic city=== [89] => "Edge city" was a term coined by [[Joel Garreau]], whereas the term "galactic city" was coined by [[Lewis Mumford]]. These terms refer to a concentration of business, shopping, and entertainment outside a traditional downtown or central business district in what had previously been a residential or rural area. There were several factors contributing to the growth of these cities such as Los Angeles, Las Vegas, Houston, and Phoenix. The factors that contributed to these large cities include reliable automobiles, highway systems, refrigeration, and agricultural production increases. Large cities such as the ones mentioned above have not been uncommon in history, but what separates these cities from the rest are that these cities are not along some natural channel of transport, or at some crossroad of two or more channels such as a trail, harbor, mountain, river, or valley. These large cities have been developed in areas that only a few hundred years ago would have been uninhabitable. Without a cost efficient way of cooling air and transporting water and food from great distances, these large cities would have never developed. The rapid growth of these cities was influenced by refrigeration and an agricultural productivity increase, allowing more distant farms to effectively feed the population. [90] => [91] => ==Impact on agriculture and food production== [92] => {{unreferenced section|date=February 2020}} [93] => Agriculture's role in developed countries has drastically changed in the last century due to many factors, including refrigeration. Statistics from the 2007 census gives information on the large concentration of agricultural sales coming from a small portion of the existing farms in the United States today. This is a partial result of the market created for the frozen meat trade by the first successful shipment of frozen sheep carcasses coming from New Zealand in the 1880s. As the market continued to grow, regulations on food processing and quality began to be enforced. Eventually, electricity was introduced into rural homes in the United States, which allowed refrigeration technology to continue to expand on the farm, increasing output per person. Today, refrigeration's use on the farm reduces humidity levels, avoids spoiling due to bacterial growth, and assists in preservation. [94] => [95] => ===Demographics=== [96] => The introduction of refrigeration and evolution of additional technologies drastically changed agriculture in the United States. During the beginning of the 20th century, farming was a common occupation and lifestyle for United States citizens, as most farmers actually lived on their farm. In 1935, there were 6.8 million farms in the United States and a population of 127 million. Yet, while the United States population has continued to climb, citizens pursuing agriculture continue to decline. Based on the 2007 US Census, less than one percent of a population of 310 million people claim farming as an occupation today. However, the increasing population has led to an increasing demand for agricultural products, which is met through a greater variety of crops, fertilizers, pesticides, and improved technology. Improved technology has decreased the risk and time involved for agricultural management and allows larger farms to increase their output per person to meet society's demand.{{cite web|title=Demographics|url=http://www.epa.gov/oecaagct/ag101/demographics.html|date=2015-03-19}} [97] => [98] => ===Meat packing and trade=== [99] => Prior to 1882, the [[South Island]] of New Zealand had been experimenting with sowing grass and crossbreeding sheep, which immediately gave their farmers economic potential in the exportation of meat. In 1882, the first successful shipment of sheep carcasses was sent from [[Port Chalmers]] in [[Dunedin]], New Zealand, to [[London]]. By the 1890s, the frozen meat trade became increasingly more profitable in New Zealand, especially in [[Canterbury Region|Canterbury]], where 50% of exported sheep carcasses came from in 1900. It was not long before Canterbury meat was known for the highest quality, creating a demand for New Zealand meat around the world. In order to meet this new demand, the farmers improved their feed so sheep could be ready for the slaughter in only seven months. This new method of shipping led to an economic boom in New Zealand by the mid 1890s.{{cite web|last=Peden|first=R.|title=Farming in the Economy-Refrigeration and Sheep Farming|url=https://teara.govt.nz/en/farming-in-the-economy/page-3}} [100] => [101] => In the United States, the Meat Inspection Act of 1891 was put in place in the United States because local butchers felt the refrigerated railcar system was unwholesome.{{cite journal|last=Libecap|title=The Rise of the Chicago Meat Packers and the Origins of Meat Inspection and Antitrust|journal=Economic Inquiry |volume=30|pages=242–262|doi=10.1111/j.1465-7295.1992.tb01656.x|s2cid=154055122|url=http://www.nber.org/papers/h0029.pdf}} When meat packing began to take off, consumers became nervous about the quality of the meat for consumption. [[Upton Sinclair]]'s 1906 novel ''[[The Jungle]]'' brought negative attention to the meat packing industry, by drawing to light unsanitary working conditions and processing of diseased animals. The book caught the attention of President [[Theodore Roosevelt]], and [[Federal Meat Inspection Act|the 1906 Meat Inspection Act]] was put into place as an amendment to the Meat Inspection Act of 1891. This new act focused on the quality of the meat and environment it is processed in.{{cite book|last=Rockoff|first=Gary M. Walton, Hugh|title=History of the American Economy|url=https://archive.org/details/historyamericane00walt_332|url-access=limited|year=2010|publisher=South-Western/Cengage Learning|location=Mason, OH|isbn=978-0-324-78661-3|pages=[https://archive.org/details/historyamericane00walt_332/page/n360 336]–368|edition=11th}} [102] => [103] => ===Electricity in rural areas=== [104] => In the early 1930s, 90 percent of the urban population of the United States [[electrification|had electric power]], in comparison to only 10 percent of rural homes. At the time, power companies did not feel that extending power to rural areas ([[rural electrification]]) would produce enough profit to make it worth their while. However, in the midst of the [[Great Depression]], President [[Franklin D. Roosevelt]] realized that rural areas would continue to lag behind urban areas in both poverty and production if they were not electrically wired. On May 11, 1935, the president signed an executive order called the [[Rural Electrification Administration]], also known as REA. The agency provided loans to fund electric infrastructure in the rural areas. In just a few years, 300,000 people in rural areas of the United States had received power in their homes. [105] => [106] => While electricity dramatically improved working conditions on farms, it also had a large impact on the safety of food production. Refrigeration systems were introduced to the farming and [[food distribution]] processes, which helped in [[food preservation]] and [[food safety|kept food supplies safe]]. Refrigeration also allowed for shipment of perishable commodities throughout the United States. As a result, United States farmers quickly became the most productive in the world,{{Citation|periodical=Rural Cooperatives|last=Campbell|first=D.|title=When the Lights Came On|url=http://www.rd.usda.gov/files/CoopMag-aug00.pdf|archive-url=https://web.archive.org/web/20150424031515/http://www.rd.usda.gov/files/CoopMag-aug00.pdf|archive-date=2015-04-24|date=August 2000}} and entire new [[food systems]] arose. [107] => [108] => ===Farm use=== [109] => In order to reduce humidity levels and spoiling due to bacterial growth, refrigeration is used for meat, produce, and dairy processing in farming today. Refrigeration systems are used the heaviest in the warmer months for farming produce, which must be cooled as soon as possible in order to meet quality standards and increase the shelf life. Meanwhile, dairy farms refrigerate milk year round to avoid spoiling.{{cite web|last=Beard|first=R.|title=Energy-Efficient Refrigeration for Farms|url=https://farm-energy.extension.org/energy-efficient-refrigeration-for-farms/}} [110] => [111] => ==Effects on lifestyle and diet== [112] => In the late 19th Century and into the very early 20th Century, except for staple foods (sugar, rice, and beans) that needed no refrigeration, the available foods were affected heavily by the seasons and what could be grown locally.{{cite journal|last=Stelpflug|first=E|title=The Food Industry and the Part That Refrigeration Plays in It|journal=Financial Analysts Journal|volume=6|issue=4|pages=37–39|doi=10.2469/faj.v6.n4.37|year=1950}}{{Cite web |title=History of America in 101 Objects© and Then Some |url=https://olli.gmu.edu/docstore/300docs/1409-320-History%20of%20America%20Part%201%20Session%203.pdf |access-date=2024-03-12 |website=refindustry.com |language=en}} Refrigeration has removed these limitations. Refrigeration played a large part in the feasibility and then popularity of the modern supermarket. Fruits and vegetables out of season, or grown in distant locations, are now available at relatively low prices. Refrigerators have led to a huge increase in meat and dairy products as a portion of overall supermarket sales.{{cite journal|last=Stelpflug|first=E.|title=Effect of Modern Refrigeration on the Modern Supermarket|journal=Financial Analysts Journal|volume=10|issue=5|pages=63–64|doi=10.2469/faj.v10.n5.63|year=1954}} As well as changing the goods purchased at the market, the ability to store these foods for extended periods of time has led to an increase in leisure time.{{citation needed|date=January 2017}} Prior to the advent of the household refrigerator, people would have to shop on a daily basis for the supplies needed for their meals.{{Cite book |last=Rees |first=Jonathan |url=https://books.google.com/books?id=JeoEAQAAQBAJ&dq=Prior+to+the+advent+of+the+household+refrigerator,+people+would+have+to+shop+on+a+daily+basis+for+the+supplies+needed+for+their+meals.&pg=PA172 |title=Refrigeration Nation: A History of Ice, Appliances, and Enterprise in America |date=2013-12-15 |publisher=JHU Press |isbn=978-1-4214-1107-1 |pages=172 |language=en}}{{Cite book |last1=Shurtleff |first1=William |url=https://books.google.com/books?id=gGrUNvZt0_YC&dq=Prior+to+the+advent+of+the+household+refrigerator,+people+would+have+to+shop+on+a+daily+basis+for+the+supplies+needed+for+their+meals.&pg=PA3319 |title=History of Tofu and Tofu Products (965 CE to 2013) |last2=Aoyagi |first2=Akiko |date=2013-05-01 |publisher=Soyinfo Center |isbn=978-1-928914-55-6 |pages=3319 |language=en}} [113] => [114] => ===Impact on nutrition=== [115] => The introduction of refrigeration allowed for the hygienic handling and storage of perishables,{{Cite book |last=Center (U.S.) |first=Food and Nutrition Information and Educational Materials |url=https://books.google.com/books?id=Rr57xpPrTVgC&dq=The+introduction+of+refrigeration+allowed+for+the+hygienic+handling+and+storage+of+perishables&pg=PA14 |title=Audiovisual Guide to the Catalog of the Food and Nutrition Information and Educational Materials Center |date=1975 |publisher=U.S. Department of Agriculture |pages=14 |language=en}} and as such, promoted output growth, consumption, and the availability of nutrition. The change in our method of food preservation moved us away from salts to a more manageable sodium level. The ability to move and store perishables such as meat and dairy led to a 1.7% increase in dairy consumption and overall protein intake by 1.25% annually in the US after the 1890s.{{cite journal|last=Craig|first=L. |author2=Goodwin B. |author3=Grennes T.|title=The Effect of Mechanical Refrigeration on Nutrition in the United States|journal=Social Science History|volume=28|issue=2|pages=325–336| doi=10.1017/S0145553200013183|year=2004|s2cid=144508403 }} [116] => [117] => People were not only consuming these perishables because it became easier for they themselves to store them, but because the innovations in refrigerated transportation and storage led to less spoilage and waste, thereby driving the prices of these products down. Refrigeration accounts for at least 5.1% of the increase in adult stature (in the US) through improved nutrition,{{Cite web |title=Bibliographies: 'Nutrition – United States – Social aspects' – Grafiati |url=https://www.grafiati.com/en/literature-selections/nutrition-united-states-social-aspects/ |access-date=2024-03-12 |website=www.grafiati.com |language=en}}{{Cite journal |last1=Craig |first1=Lee A. |last2=Goodwin |first2=Barry |last3=Grennes |first3=Thomas |date=2004 |title=The Effect of Mechanical Refrigeration on Nutrition in the United States |url=https://www.jstor.org/stable/40267845 |journal=Social Science History |volume=28 |issue=2 |pages=325–336 |jstor=40267845 |issn=0145-5532}} and when the indirect effects associated with improvements in the quality of nutrients and the reduction in illness is additionally factored in, the overall impact becomes considerably larger. Recent studies have also shown a negative relationship between the number of refrigerators in a household and the rate of gastric cancer mortality.{{cite journal|last=Park|first=B. |author2=Shin A. |author3=Yoo, K.|title=Ecological Study for Refrigerator Use, Salt, Vegetable, and Fruit Intakes, and Gastric Cancer|journal=Cancer Causes & Control|volume=22|issue=11|pages=1497–1502|doi=10.1007/s10552-011-9823-7|pmid=21805052 |display-authors=etal|year=2011|s2cid=24595562 }} [118] => [119] => ==Current applications of refrigeration== [120] => Probably the most widely used current applications of refrigeration are for [[air conditioning]] of private homes and public buildings, and refrigerating foodstuffs in homes, restaurants and large storage warehouses. The use of [[refrigerator]]s and walk-in coolers and freezers in kitchens, factories and warehouses {{Cite web|url=https://www.heatcraftrpd.com/productcatalog/familydetail.aspx?&FilterCol=&FilterVal=&LPNO=5&catID=HC113&pageNo=4&sort=Capacity+(BTUH)&cID=2|title=Heatcraft Refrigeration Products | Heatcraft Worldwide Refrigeration|website=www.heatcraftrpd.com|access-date=2019-12-15|archive-date=2020-02-29|archive-url=https://web.archive.org/web/20200229150108/https://www.heatcraftrpd.com/productcatalog/familydetail.aspx?&FilterCol=&FilterVal=&LPNO=5&catID=HC113&pageNo=4&sort=Capacity+(BTUH)&cID=2|url-status=dead}}{{Cite web|url=https://www.heatcraftrpd.com/productcatalog/familydetail.aspx?&FilterCol=&FilterVal=&LPNO=5&catID=HC058&pageNo=1&sort=Capacity+(BTUH)&cID=2|title=Heatcraft Refrigeration Products | Heatcraft Worldwide Refrigeration|website=www.heatcraftrpd.com|access-date=2019-12-15|archive-date=2020-02-29|archive-url=https://web.archive.org/web/20200229140028/https://www.heatcraftrpd.com/productcatalog/familydetail.aspx?&FilterCol=&FilterVal=&LPNO=5&catID=HC058&pageNo=1&sort=Capacity+(BTUH)&cID=2|url-status=dead}}{{Cite web|url=https://russell.htpg.com/unit-coolers/walk-in/|title=Russell - Walk-In|website=russell.htpg.com}}{{Cite web|url=https://coldzone.htpg.com/unit-coolers/|title=Coldzone - Unit Coolers|website=coldzone.htpg.com}}{{Cite web|url=https://www.heatcraftrpd.com/productcatalog/categorylist.aspx?catID=HC007&cID=4|title=Heatcraft Refrigeration Products | Heatcraft Worldwide Refrigeration|website=www.heatcraftrpd.com|access-date=2019-12-15|archive-date=2019-12-15|archive-url=https://web.archive.org/web/20191215052523/https://www.heatcraftrpd.com/productcatalog/categorylist.aspx%3FcatID%3DHC007%26cID%3D4|url-status=dead}} for storing and processing fruits and vegetables has allowed adding fresh salads to the modern diet year round, and storing fish and meats safely for long periods. [121] => The optimum temperature range for perishable food storage is {{convert|3|to|5|C|F}}.[https://web.archive.org/web/20090213114520/http://www.bbc.co.uk/bloom/actions/fridgefreezertips.shtml Keep your fridge-freezer clean and ice-free]. ''BBC''. 30 April 2008 [122] => [123] => In commerce and manufacturing, there are many uses for refrigeration. Refrigeration is used to liquefy gases – [[oxygen]], [[nitrogen]], [[propane]], and [[methane]], for example. In compressed air purification, it is used to [[condensation|condense]] water vapor from compressed air to reduce its moisture content. In [[oil refinery|oil refineries]], [[chemical plant]]s, and [[petrochemical]] plants, refrigeration is used to maintain certain processes at their needed low temperatures (for example, in [[alkylation]] of [[butene]]s and [[butane]] to produce a high-[[octane rating|octane]] gasoline component). Metal workers use refrigeration to temper steel and cutlery. When transporting temperature-sensitive foodstuffs and other materials by trucks, trains, airplanes and seagoing vessels, refrigeration is a necessity. [124] => [125] => Dairy products are constantly in need of refrigeration,{{Cite web |title=Keeping Dairy Foods Safe {{!}} American Dairy Association NE |url=https://www.americandairy.com/health-wellness/food-safety/ |access-date=2024-03-12 |website=American Dairy Association North East |language=en-US}} and it was only discovered in the past few decades that eggs needed to be refrigerated during shipment rather than waiting to be refrigerated after arrival at the grocery store. Meats, poultry and fish all must be kept in climate-controlled environments before being sold.{{Cite book |last=Crawley |first=Gerard M. |url=https://books.google.com/books?id=tQUlEAAAQBAJ&dq=%22Meats,+poultry+and+fish+all+must+be+kept+in+climate-controlled+environments+before+being+sold%22&pg=PA120 |title=Wind, Water And Fire: The Other Renewable Energy Resources |date=2021-02-25 |publisher=World Scientific |isbn=978-981-12-2593-2 |pages=120 |language=en}} Refrigeration also helps keep fruits and vegetables edible longer. [126] => [127] => One of the most influential uses of refrigeration was in the development of the [[sushi]]/[[sashimi]] industry in Japan.{{Cite web |last=Ahire |first=Niraj |date=2022-12-16 |title=A Study on Refrigeration |url=https://www.ijsr.net/archive/v3i5/MDIwMTMyMDQx.pdf |access-date=2024-03-12 |language=en}}{{Cite web |last=Ahire |first=Niraj |date=2022-12-16 |title=Cryogenic Refrigeration |url=https://medium.com/@niraj.ahire19/cryogenic-refrigeration-a91eae4a877 |access-date=2024-03-12 |website=Medium |language=en}} Before the discovery of refrigeration, many sushi connoisseurs were at risk of contracting diseases. The dangers of unrefrigerated sashimi were not brought to light for decades due to the lack of research and healthcare distribution across rural Japan. Around mid-century, the [[Zojirushi]] corporation, based in Kyoto, made breakthroughs in refrigerator designs, making refrigerators cheaper and more accessible for restaurant proprietors and the general public. [128] => [129] => ==Methods of refrigeration== [130] => Methods of refrigeration can be classified as ''non-cyclic'', ''cyclic'', ''thermoelectric'' and ''magnetic''. [131] => [132] => ===Non-cyclic refrigeration=== [133] => {{Main|Ice trade}} [134] => This refrigeration method cools a contained area by melting ice, or by sublimating [[dry ice]].{{cite web [135] => |url= https://www.brighthubengineering.com/hvac/20353-methods-of-refrigeration-ice-refrigeration-and-dry-ice-refrigeration/ [136] => |title= Methods of Refrigeration: Ice Refrigeration, Dry Ice Refrigeration [137] => |website= Brighthub Engineering [138] => |access-date= 2016-02-29 [139] => |date= 2008-12-22 [140] => }} Perhaps the simplest example of this is a portable cooler, where items are put in it, then ice is poured over the top. Regular ice can maintain temperatures near, but not below the freezing point, unless salt is used to cool the ice down further (as in a [[ice cream maker#Hand-cranked machines|traditional ice-cream maker]]). Dry ice can reliably bring the temperature well below water freezing point. [141] => [142] => ===Cyclic refrigeration=== [143] => {{Main|Heat pump and refrigeration cycle}} [144] => This consists of a refrigeration cycle, where heat is removed from a low-temperature space or source and rejected to a high-temperature sink with the help of external work, and its inverse, the [[thermodynamic power cycle]]. In the power cycle, heat is supplied from a high-temperature source to the engine, part of the heat being used to produce work and the rest being rejected to a low-temperature sink. This satisfies the [[second law of thermodynamics]]. [145] => [146] => A ''refrigeration cycle'' describes the changes that take place in the refrigerant as it alternately absorbs and rejects heat as it circulates through a [[refrigerator]]. It is also applied to heating, ventilation, and air conditioning [[HVACR]] work, when describing the "process" of refrigerant flow through an HVACR unit, whether it is a packaged or split system. [147] => [148] => Heat naturally flows from hot to cold. [[Mechanical work|Work]] is applied to cool a living space or storage volume by pumping heat from a lower temperature heat source into a higher temperature heat sink. [[Thermal insulation|Insulation]] is used to reduce the work and [[energy]] needed to achieve and maintain a lower temperature in the cooled space. The operating principle of the refrigeration cycle was described mathematically by [[Nicolas Léonard Sadi Carnot|Sadi Carnot]] in 1824 as a [[Carnot heat engine|heat engine]]. [149] => [150] => The most common types of refrigeration systems use the reverse-Rankine [[vapor-compression refrigeration]] cycle, although [[absorption heat pump]]s are used in a minority of applications. [151] => [152] => Cyclic refrigeration can be classified as: [153] => #Vapor cycle, and [154] => #Gas cycle [155] => [156] => Vapor cycle refrigeration can further be classified as: [157] => #[[Vapor-compression refrigeration]] [158] => #Sorption Refrigeration [159] => ##[[Absorption refrigerator|Vapor-absorption refrigeration]] [160] => ##[[Adsorption refrigeration]] [161] => [162] => ====Vapor-compression cycle==== [163] => {{See also|Vapor-compression refrigeration}} [164] => [[File:Refrigeration.png|frame|right|Figure 1: Vapor compression refrigeration]] [165] => [[File:RefrigerationTS.png|frame|right|Figure 2: Temperature–Entropy diagram]] [166] => The vapor-compression cycle is used in most household refrigerators as well as in many large commercial and [[Industrial refrigerator|industrial refrigeration]] systems. Figure 1 provides a schematic diagram of the components of a typical vapor-compression refrigeration system. [167] => [168] => The [[thermodynamics]] of the cycle can be analyzed on a diagram[http://web.me.unr.edu/me372/Spring2001/Vapor%20Compression%20Refrigeration%20Cycles.pdf The Ideal Vapor-Compression Cycle] {{webarchive|url=https://web.archive.org/web/20070226113352/http://web.me.unr.edu/me372/Spring2001/Vapor%20Compression%20Refrigeration%20Cycles.pdf |date=2007-02-26}} as shown in Figure 2. In this cycle, a circulating refrigerant such as a low boiling hydrocarbon or [[hydrofluorocarbons]] enters the [[gas compressor|compressor]] as a vapour. From point 1 to point 2, the vapor is compressed at constant [[entropy]] and exits the compressor as a vapor at a higher temperature, but still below the [[vapor pressure]] at that temperature. From point 2 to point 3 and on to point 4, the vapor travels through the [[condenser (heat transfer)|condenser]] which cools the vapour until it starts condensing, and then condenses the vapor into a liquid by removing additional heat at constant pressure and temperature. Between points 4 and 5, the liquid refrigerant goes through the [[thermal expansion valve|expansion valve]] (also called a throttle valve) where its pressure abruptly decreases, causing [[flash evaporation]] and auto-refrigeration of, typically, less than half of the liquid. [169] => [170] => That results in a mixture of liquid and vapour at a lower temperature and pressure as shown at point 5. The cold liquid-vapor mixture then travels through the evaporator coil or tubes and is completely vaporized by cooling the warm air (from the space being refrigerated) being blown by a fan across the evaporator coil or tubes. The resulting refrigerant vapour returns to the compressor inlet at point 1 to complete the thermodynamic cycle. [171] => [172] => The above discussion is based on the ideal vapour-compression refrigeration cycle, and does not take into account real-world effects like frictional pressure drop in the system, slight [[thermodynamic reversibility|thermodynamic irreversibility]] during the compression of the refrigerant vapor, or [[ideal gas|non-ideal gas]] behavior, if any. Vapor compression refrigerators can be arranged in two stages in [[cascade refrigeration]] systems, with the second stage cooling the condenser of the first stage. This can be used for achieving very low temperatures. [173] => [174] => More information about the design and performance of vapor-compression refrigeration systems is available in the classic ''[[Perry's Chemical Engineers' Handbook]]''.{{cite book|author1=Perry, R.H. |author2=Green, D.W. |name-list-style=amp |title=Perry's Chemical Engineers' Handbook|edition=6th |publisher=McGraw Hill, Inc.|year=1984|isbn=978-0-07-049479-4|title-link=Perry's Chemical Engineers' Handbook}} (see pp. 12-27 through 12-38) [175] => [176] => ====Sorption cycle==== [177] => {{unreferenced section|date=February 2020}} [178] => [179] => =====Absorption cycle===== [180] => {{Main|Absorption refrigerator}} [181] => In the early years of the twentieth century, the vapor absorption cycle using water-ammonia systems or [[lithium bromide|LiBr]]-water was popular and widely used. After the development of the vapor compression cycle, the vapor absorption cycle lost much of its importance because of its low [[coefficient of performance]] (about one fifth of that of the vapor compression cycle). Today, the vapor absorption cycle is used mainly where fuel for heating is available but electricity is not, such as in [[recreational vehicles]] that carry [[liquefied petroleum gas|LP gas]]. It is also used in industrial environments where plentiful waste heat overcomes its inefficiency. [182] => [183] => The absorption cycle is similar to the compression cycle, except for the method of raising the pressure of the refrigerant vapor. In the absorption system, the compressor is replaced by an absorber which dissolves the refrigerant in a suitable liquid, a liquid pump which raises the pressure and a generator which, on heat addition, drives off the refrigerant vapor from the high-pressure liquid. Some work is needed by the liquid pump but, for a given quantity of refrigerant, it is much smaller than needed by the compressor in the vapor compression cycle. In an absorption refrigerator, a suitable combination of refrigerant and absorbent is used. The most common combinations are ammonia (refrigerant) with water (absorbent), and water (refrigerant) with lithium bromide (absorbent). [184] => [185] => =====Adsorption cycle===== [186] => {{Main|Adsorption refrigeration}} [187] => The main difference with absorption cycle, is that in adsorption cycle, the refrigerant (adsorbate) could be ammonia, water, [[methanol]], etc., while the adsorbent is a solid, such as [[silica gel]], [[activated carbon]], or [[zeolite]], unlike in the absorption cycle where absorbent is liquid. [188] => [189] => The reason adsorption refrigeration technology has been extensively researched in recent 30 years lies in that the operation of an adsorption refrigeration system is often noiseless, non-corrosive and environment friendly.{{Cite journal|last1=Goyal|first1=Parash|last2=Baredar|first2=Prashant|last3=Mittal|first3=Arvind|last4=Siddiqui|first4=Ameenur. R.|date=2016-01-01|title=Adsorption refrigeration technology – An overview of theory and its solar energy applications|journal=Renewable and Sustainable Energy Reviews|language=en|volume=53|pages=1389–1410|doi=10.1016/j.rser.2015.09.027|issn=1364-0321}} [190] => [191] => ====Gas cycle==== [192] => {{unreferenced section|date=February 2020}} [193] => When the [[working fluid]] is a gas that is compressed and expanded but does not change phase, the refrigeration cycle is called a ''gas cycle''. [[Air]] is most often this working fluid. As there is no condensation and evaporation intended in a gas cycle, components corresponding to the condenser and evaporator in a vapor compression cycle are the hot and cold gas-to-gas [[heat exchanger]]s in gas cycles. [194] => [195] => The gas cycle is less efficient than the vapor compression cycle because the gas cycle works on the reverse [[Brayton cycle]] instead of the reverse [[Rankine cycle]]. As such, the working fluid does not receive and reject heat at constant temperature. In the gas cycle, the refrigeration effect is equal to the product of the specific heat of the gas and the rise in temperature of the gas in the low temperature side. Therefore, for the same cooling load, a gas refrigeration cycle needs a large mass flow rate and is bulky. [196] => [197] => Because of their lower efficiency and larger bulk, ''air cycle'' coolers are not often used nowadays in terrestrial cooling devices. However, the [[air cycle machine]] is very common on [[gas turbine]]-powered jet [[aircraft]] as cooling and ventilation units, because compressed air is readily available from the engines' compressor sections. Such units also serve the purpose of pressurizing the aircraft. [198] => [199] => ===Thermoelectric refrigeration=== [200] => [[Thermoelectric cooling]] uses the [[Peltier effect]] to create a heat [[flux]] between the junction of two types of material.{{Cite book |last=Lundgaard |first=Christian |title=Design of segmented thermoelectric Peltier coolers by topology optimization |publisher=OXFORD: Elsevier Ltd |year=2019 |pages=1 |language=English}} This effect is commonly used in camping and portable coolers and for cooling electronic componentsFylladitakis, E. (September 26, 2016) [http://www.anandtech.com/show/10695/the-phononic-hex-2-0-tec-cpu-cooler-review The Phononic HEX 2.0 TEC CPU Cooler Review]. Anandtech.com. Retrieved on 2018-10-31. and small instruments. Peltier coolers are often used where a traditional vapor-compression cycle refrigerator would be impractical or take up too much space, and in cooled image sensors as an easy, compact and lightweight, if inefficient, way to achieve very low temperatures, using two or more stage peltier coolers arranged in a [[cascade refrigeration]] configuration, meaning that two or more Peltier elements are stacked on top of each other, with each stage being larger than the one before it,{{Cite book|url=https://books.google.com/books?id=rKy-DwAAQBAJ&dq=cascade+peltier+cooler&pg=PA95|title=Conductors, Semiconductors, Superconductors: An Introduction to Solid-State Physics|first=Rudolf P.|last=Huebener|date=November 16, 2019|publisher=Springer Nature|isbn=9783030314200 |via=Google Books}}{{Cite book|url=https://books.google.com/books?id=n4O1DwAAQBAJ&dq=peltier+stages&pg=PA625|title=CRC Handbook of Thermoelectrics|first=D. M.|last=Rowe|date=December 7, 2018|publisher=CRC Press|isbn=9780429956676 |via=Google Books}}{{Cite book|url=https://books.google.com/books?id=Zut8CAAAQBAJ&dq=peltier+stages&pg=PA9|title=Thermoelectric Bi2Te3 Nanomaterials|first1=Oliver|last1=Eibl|first2=Kornelius|last2=Nielsch|first3=Nicola|last3=Peranio|first4=Friedemann|last4=Völklein|date=April 21, 2015|publisher=John Wiley & Sons|isbn=9783527672639 |via=Google Books}} in order to extract more heat and waste heat generated by the previous stages. Peltier cooling has a low COP (efficiency) when compared with that of the vapor-compression cycle, so it emits more waste heat (heat generated by the Peltier element or cooling mechanism) and consumes more power for a given cooling capacity.{{cite web |last=Brown |first=D. R.| title=The Prospects of Alternatives to Vapor Compression Technology for Space Cooling and Food Refrigeration Applications |url=http://www.pnl.gov/main/publications/external/technical_reports/pnnl-19259.pdf |work=Pacific Northwest National Laboratory (PNL) |publisher=U.S. Department of Energy |access-date=16 March 2013 |author2=N. Fernandez |author3=J. A. Dirks |author4=T. B. Stout |date=March 2010}} [201] => [202] => ===Magnetic refrigeration=== [203] => {{Main|Magnetic refrigeration}} [204] => {{unreferenced section|date=February 2020}} [205] => Magnetic refrigeration, or [[adiabatic]] [[demagnetization]], is a cooling technology based on the magnetocaloric effect, an [[intrinsic and extrinsic properties|intrinsic property]] of magnetic solids. The refrigerant is often a [[paramagnetism|paramagnetic]] [[salt (chemistry)|salt]], such as [[cerium]] [[magnesium]] [[nitrate]]. The active [[magnetic field|magnetic]] [[dipole]]s in this case are those of the [[electron shell]]s of the paramagnetic atoms. [206] => [207] => A strong magnetic field is applied to the refrigerant, forcing its various magnetic dipoles to align and putting these degrees of freedom of the refrigerant into a state of lowered [[entropy]]. A heat sink then absorbs the heat released by the refrigerant due to its loss of entropy. Thermal contact with the heat sink is then broken so that the system is insulated, and the magnetic field is switched off. This increases the heat capacity of the refrigerant, thus decreasing its temperature below the temperature of the heat sink. [208] => [209] => Because few materials exhibit the needed properties at room temperature, applications have so far been limited to [[cryogenics]] and research. [210] => [211] => ===Other methods=== [212] => {{unreferenced section|date=February 2020}} [213] => Other methods of refrigeration include the [[air cycle machine]] used in aircraft; the [[vortex tube]] used for spot cooling, when compressed air is available; and [[thermoacoustic refrigeration]] using sound waves in a pressurized gas to drive heat transfer and heat exchange; [[steam jet cooling]] popular in the early 1930s for air conditioning large buildings; thermoelastic cooling using a smart metal alloy stretching and relaxing. Many [[Stirling cycle]] heat engines can be run backwards to act as a refrigerator, and therefore these engines have a niche use in [[cryogenics]]. In addition, there are other types of [[cryocoolers]] such as Gifford-McMahon coolers, Joule-Thomson coolers, [[Pulse tube refrigerator|pulse-tube refrigerators]] and, for temperatures between 2 mK and 500 mK, [[dilution refrigerator]]s. [214] => [215] => ===Elastocaloric refrigeration=== [216] => Another potential solid-state refrigeration technique and a relatively new area of study comes from a special property of [[pseudoelasticity|super elastic]] materials. These materials undergo a temperature change when experiencing an applied mechanical [[stress (mechanics)|stress]] (called the elastocaloric effect). Since super elastic materials deform reversibly at high [[strain (mechanics)|strains]], the material experiences a flattened [[elasticity (physics)|elastic]] region in its [[stress-strain curve]] caused by a resulting phase transformation from an [[austenite|austenitic]] to a [[martensite|martensitic]] crystal phase. [217] => [218] => When a super elastic material experiences a stress in the austenitic phase, it undergoes an [[exothermic]] [[phase transition|phase transformation]] to the martensitic phase, which causes the material to heat up. Removing the stress reverses the process, restores the material to its austenitic phase, and [[endothermic process|absorbs heat]] from the surroundings cooling down the material. [219] => [220] => The most appealing part of this research is how potentially energy efficient and environmentally friendly this cooling technology is. The different materials used, commonly [[shape-memory alloy]]s, provide a non-toxic source of emission free refrigeration. The most commonly studied materials studied are shape-memory alloys, like [[nitinol]] and Cu-Zn-Al. Nitinol is of the more promising alloys with output heat at about 66 J/cm3 and a temperature change of about 16–20 K.{{cite journal|last1=Tušek|first1=J.|last2=Engelbrecht|first2=K.|last3=Mikkelsen|first3=L.P.|last4=Pryds|first4=N.|title=Elastocaloric effect of Ni-Ti wire for application in a cooling device|journal=Journal of Applied Physics|date=February 2015|volume=117|issue=12|pages=124901|doi=10.1063/1.4913878|bibcode=2015JAP...117l4901T|s2cid=54708904 }} Due to the difficulty in manufacturing some of the shape memory alloys, alternative materials like [[natural rubber]] have been studied. Even though rubber may not give off as much heat per volume (12 J/cm3 ) as the shape memory alloys, it still generates a comparable temperature change of about 12 K and operates at a suitable temperature range, low stresses, and low cost.{{cite journal|last1=Xie|first1=Zhongjian|last2=Sebald|first2=Gael|last3=Guyomar|first3=Daniel|title=Temperature dependence of the elastocaloric effect in natural rubber|journal=Physics Letters A|date=21 February 2017|volume=381|issue=25–26|pages=2112–2116|doi=10.1016/j.physleta.2017.02.014|arxiv=1604.02686|bibcode=2017PhLA..381.2112X|s2cid=119218238}} [221] => [222] => The main challenge however comes from potential energy losses in the form of [[hysteresis]], often associated with this process. Since most of these losses comes from incompatibilities between the two phases, proper alloy tuning is necessary to reduce losses and increase reversibility and [[energy conversion efficiency|efficiency]]. Balancing the transformation strain of the material with the energy losses enables a large elastocaloric effect to occur and potentially a new alternative for refrigeration.{{cite journal|last1=Lu|first1=Benfeng|last2=Liu|first2=Jian|title=Elastocaloric effect and superelastic stability in Ni–Mn–In–Co polycrystalline Heusler alloys: hysteresis and strain-rate effects|journal=Scientific Reports|date=18 May 2017|volume=7|issue=1|pages=2084|doi=10.1038/s41598-017-02300-3|pmid=28522819|pmc=5437036|bibcode=2017NatSR...7.2084L}} [223] => [224] => ===Fridge Gate=== [225] => The Fridge Gate method is a theoretical application of using a single logic gate to drive a refrigerator in the most energy efficient way possible without violating the laws of thermodynamics. It operates on the fact that there are two energy states in which a particle can exist: the ground state and the excited state. The excited state carries a little more energy than the ground state, small enough so that the transition occurs with high probability. There are three components or particle types associated with the fridge gate. The first is on the interior of the refrigerator, the second on the outside and the third is connected to a power supply which heats up every so often that it can reach the E state and replenish the source. In the cooling step on the inside of the refrigerator, the g state particle absorbs energy from ambient particles, cooling them, and itself jumping to the e state. In the second step, on the outside of the refrigerator where the particles are also at an e state, the particle falls to the g state, releasing energy and heating the outside particles. In the third and final step, the power supply moves a particle at the e state, and when it falls to the g state it induces an energy-neutral swap where the interior e particle is replaced by a new g particle, restarting the cycle.{{cite journal|author=Renato Renner|author-link=Renato Renner|date=9 February 2012|title=Thermodynamics: The fridge gate|journal=Nature|volume=482|issue=7384|pages=164–165|bibcode=2012Natur.482..164R|doi=10.1038/482164a|pmid=22318595|doi-access=free|s2cid=4416925}} [226] => [227] => ===Passive systems=== [228] => When combining a [[passive daytime radiative cooling]] system with [[thermal insulation]] and [[Evaporative cooler|evaporative cooling]], one study found a 300% increase in ambient cooling power when compared to a stand-alone radiative cooling surface, which could extend the [[shelf life]] of food by 40% in [[Humidity|humid climates]] and 200% in [[Desert climate|desert climates]] without refrigeration. The system's evaporative cooling layer would require water "re-charges" every 10 days to a month in humid areas and every 4 days in hot and dry areas.{{Cite journal |last1=Lu |first1=Zhengmao |last2=Leroy |first2=Arny |last3=Zhang |first3=Lenan |last4=Patel |first4=Jatin J. |last5=Wang |first5=Evelyn N. |last6=Grossman |first6=Jeffrey C. |date=September 2022 |title=Significantly enhanced sub-ambient passive cooling enabled by evaporation, radiation, and insulation |journal=Cell Reports Physical Science |volume=3 |issue=10 |page=101068 |doi=10.1016/j.xcrp.2022.101068 |bibcode=2022CRPS....301068L |s2cid=252411940 |doi-access=free |hdl=1721.1/146578 |hdl-access=free }} [229] => [230] => ==Capacity ratings== [231] => {{unreferenced section|date=February 2020}} [232] => The refrigeration capacity of a refrigeration system is the product of the [[evaporator]]s' [[enthalpy]] rise and the evaporators' [[mass flow rate]]. The measured capacity of refrigeration is often dimensioned in the unit of kW or BTU/h. Domestic and commercial refrigerators may be rated in kJ/s, or Btu/h of cooling. For commercial and industrial refrigeration systems, the '''kilowatt''' (kW) is the basic unit of refrigeration, except in North America, where both '''[[ton of refrigeration]]''' and BTU/h are used. [233] => [234] => A refrigeration system's '''[[coefficient of performance]]''' (CoP) is very important in determining a system's overall efficiency. It is defined as refrigeration capacity in kW divided by the energy input in kW. While CoP is a very simple measure of performance, it is typically not used for industrial refrigeration in North America. Owners and manufacturers of these systems typically use '''performance factor''' (PF). A system's PF is defined as a system's energy input in horsepower divided by its refrigeration capacity in TR. Both CoP and PF can be applied to either the entire system or to system components. For example, an individual compressor can be rated by comparing the energy needed to run the compressor versus the expected refrigeration capacity based on inlet volume flow rate. It is important to note that both CoP and PF for a refrigeration system are only defined at specific operating conditions, including temperatures and thermal loads. Moving away from the specified operating conditions can dramatically change a system's performance. [235] => [236] => Air conditioning systems used in residential application typically use [[Seasonal energy efficiency ratio|SEER]] (Seasonal Energy Efficiency Ratio)for the energy performance rating.{{Cite web|title=Seasonal Energy Efficiency Ratio|url=http://www.ahrinet.org/Homeowners/Save-Energy/Seasonal-Energy-Efficiency-Ratio|access-date=2020-06-09|website=www.ahrinet.org}} Air conditioning systems for commercial application often use EER ([[Energy efficiency ratio|Energy Efficiency Ratio]]) and IEER (Integrated Energy Efficiency Ratio) for the energy efficiency performance rating.{{Cite conference|last1=Calderone|first1=Anthony Domenic|last2=Hessami|first2=Mir-Akbar|last3=Brey|first3=Stefan|date=2005-01-01|title=Use of Solar Desiccant Air-Conditioning Systems in Commercial Buildings|conference=ASME 2005 International Solar Energy Conference |pages=71–78|publisher=ASMEDC|doi=10.1115/isec2005-76107|isbn=0-7918-4737-3}} [237] => [238] => ==See also== [239] => {{Div col|colwidth=30em}} [240] => *[[Air conditioning]] [241] => *[[Auto-defrost]] [242] => *[[Beef ring]] [243] => *[[Carnot heat engine]] [244] => *[[Cold chain]] [245] => *[[Coolgardie safe]] [246] => *[[Cryocooler]] [247] => *[[Darcy friction factor formulae]] [248] => *[[Einstein refrigerator]] [249] => *[[Freezer]] [250] => *[[Heat pump]] [251] => *[[Heat pump and refrigeration cycle]] [252] => *[[Heating, ventilation, and air conditioning]] (HVAC, HVACR) [253] => *[[Icebox]] [254] => *[[Icyball]] [255] => *[[Joule–Thomson effect]] [256] => *[[Laser cooling]] [257] => *[[Pot-in-pot refrigerator]] [258] => *[[Pumpable ice technology]] [259] => *[[Quantum refrigerators]] [260] => *[[Redundant refrigeration system]] [261] => *[[Reefer ship]] [262] => *[[Refrigerant]] [263] => *[[Refrigerated container]] [264] => *[[Refrigerator]] [265] => *[[Refrigerator car]] [266] => *[[Refrigerator truck]] [267] => *[[Seasonal energy efficiency ratio]] (SEER) [268] => *[[Steam jet cooling]] [269] => *[[Thermoacoustics]] [270] => *[[Vapor-compression refrigeration]] [271] => *[[Working fluid]] [272] => *[[World Refrigeration Day]] [273] => {{Div col end}} [274] => [275] => ==References== [276] => {{Reflist}} [277] => [278] => ==Further reading== [279] => *''Refrigeration volume'', [[ASHRAE Handbook]], ASHRAE, Inc., Atlanta, GA [280] => *Stoecker and Jones, ''Refrigeration and Air Conditioning'', Tata-McGraw Hill Publishers [281] => *Mathur, M.L., Mehta, F.S., ''Thermal Engineering'' Vol II [282] => *MSN Encarta Encyclopedia [283] => *{{cite book|author1=Andrew D. Althouse |author2=Carl H. Turnquist |author3=Alfred F. Bracciano |title=Modern Refrigeration and Air Conditioning|edition=18th|publisher=Goodheart-Wilcox Publishing|year=2003|isbn=978-1-59070-280-2}} [284] => *{{cite book [285] => |publisher=Kennikat Press [286] => |isbn= 978-0-8046-1621-8 [287] => |page= 344 [288] => |last= Anderson [289] => |first= Oscar Edward [290] => |title= Refrigeration in America: A history of a new technology and its impact [291] => |year= 1972 [292] => }} [293] => *{{cite book [294] => |publisher=Mariner Books [295] => |isbn= 978-0-618-08239-1 [296] => |page= 272 [297] => |last= Shachtman [298] => |first= Tom [299] => |title= Absolute Zero: And the Conquest of Cold [300] => |year= 2000 [301] => }} [302] => *{{cite book [303] => |edition= 1st [304] => |publisher=Exposition Press [305] => |page= 212 [306] => |last= Woolrich [307] => |first= Willis Raymond [308] => |title= The men who created cold: A history of refrigeration [309] => |year= 1967 [310] => }} [311] => [312] => ==External links== [313] => *[https://www.green-cooling-initiative.org/ Green Cooling Initiative on alternative natural refrigerants cooling technologies] [314] => *[https://home.howstuffworks.com/refrigerator4.htm "The Refrigeration Cycle", from HowStuffWorks] [315] => *[http://www.frigokey.com.tr/sogutma-sistemi-nedir "The Refrigeration", from frigokey] {{Webarchive|url=https://web.archive.org/web/20170320054305/http://www.frigokey.com.tr/sogutma-sistemi-nedir |date=2017-03-20 }} [316] => *[https://www.ashrae.org/ American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE)] [317] => *[http://www.iifiir.org/ International Institute of Refrigeration (IIR)] [318] => *[https://ior.org.uk/ British Institute of Refrigeration] [319] => *[http://www.nh3tech.org/absorption.html Scroll down to "Continuous-Cycle Absorption System"] [320] => *[http://www.eere.energy.gov/de/thermally_activated/tech_basics.html US Department of Energy: Technology Basics of Absorption Cycles] [321] => *[https://www.ior.org.uk/ Institute of Refrigeration] [322] => [323] => {{HVAC}} [324] => {{Authority control}} [325] => [[Category:Chemical processes]] [326] => [[Category:Cooling technology]] [327] => [[Category:Food preservation]] [328] => [[Category:Heating, ventilation, and air conditioning]] [329] => [[Category:Thermodynamics]] [] => )
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Refrigeration

Refrigeration is a process of cooling a space, substance, or system to lower and maintain its temperature below the surrounding environment. It is commonly used in households, industries, and transportation to preserve food, medication, and other perishable items, as well as to provide comfort in hot weather.

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It is commonly used in households, industries, and transportation to preserve food, medication, and other perishable items, as well as to provide comfort in hot weather. The basic principle of refrigeration is the removal of heat from a space or substance, typically through the use of a refrigerant, a fluid that absorbs heat as it changes state from a liquid to a gas and releases heat when it condenses back into a liquid. This process is achieved through a refrigeration system, which generally consists of a compressor, condenser, evaporator, and expansion valve. Early forms of refrigeration were developed in ancient times, with the use of ice and snow to cool food and beverages. However, it wasn't until the 18th and 19th centuries that significant advancements were made in refrigeration technology. The invention of the refrigeration machine by Oliver Evans in 1805 and the development of the vapor compression cycle by Jacob Perkins in 1834 laid the foundation for modern refrigeration systems. Since then, refrigeration has become an essential part of daily life. It has revolutionized the food industry by extending the shelf life of perishable goods, reducing waste, and enabling the transportation of food over long distances. Refrigeration also plays a crucial role in various industries, such as pharmaceuticals, chemicals, and manufacturing, where precise temperature control is necessary for production processes. Additionally, refrigeration has significantly impacted domestic comfort, with the invention of residential refrigerators and air conditioning systems. These advancements have improved living conditions, particularly in hot climates, by providing a controlled and comfortable environment. The environmental impact of refrigeration is an ongoing concern. The use of certain refrigerants, such as chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs), has been phased out due to their harmful effects on the ozone layer and contribution to global warming. The industry has transitioned to more environmentally friendly alternatives, such as hydrofluorocarbons (HFCs) and natural refrigerants like ammonia, carbon dioxide, and hydrocarbons. In conclusion, refrigeration is a crucial technology that has transformed various aspects of modern life. From preserving food to providing comfort, it has become an integral part of our daily routines. Ongoing advancements aim to make refrigeration more sustainable and energy-efficient, ensuring a greener future.

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