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Friday 21 July 2017

Refrigeration

Refrigeration is the application of cold for the preservation of food. The application is old, and cold caverns, cellars and where available snow have always been used for the purpose.

There is a 5000 year old refrigeration technique using only principles of evaporation and humidity that can be produced with basic pottery, sand, a rag, and water.

Ancient Egyptian Pharaohs made slaves fan their wine all night to cool it down.

By 400 BC, Persian engineers had mastered the technique of storing ice in the middle of summer in the desert.

Few colonial Americans used ice to refrigerate foods due to a lack of ice-storehouses and iceboxes. By the the 19th century these two things became more widely available, and individuals used axes and saws to harvest ice for their storehouses.

Ice became a mass-market commodity by the early 1830s in the US with the price of ice dropping from six cents per pound to a half of a cent per pound. This ice market further expanded further with the introduction of railroads to transport it.


Ice harvesting in Massachusetts, 1852, showing the railroad line in the background

Ice harvesting created a “cooling culture” as many used ice and iceboxes to store their fish, meat, dairy products 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

American inventor Oliver Evans, designed the first closed circuit refrigeration machine that used vapor instead of liquid in 1805.

Another American inventor Jacob Perkins is known as the father of the refrigerator. He is credited with the first patent for the vapor-compression refrigeration cycle, assigned on August 14, 1835 and titled, "Apparatus and means for producing ice, and in cooling fluids." The idea had come from Oliver Evans' design, who never constructed his refrigeration machine.


Jacob Perkins was the first to describe how pipes filled with volatile chemicals whose molecules evaporated very easily could keep food cool, like wind chilling your skin after a dip in the sea. But he neglected to publicize his invention and its evolution was slow.

An American doctor, John Gorrie of Apalachicola, Florida was granted Patent No. 8080 for a machine to make ice on May 6, 1851. His design was based on the ones of  Oliver Evans and Jacob Perkins' and was intended to make ice to cool the air for his yellow fever patients. Gorrie sought to raise money to manufacture his machine, but the venture failed when his partner died.


James Harrison, the Scottish/Australian owner of the Geelong Advertiser became interested in refrigeration when whilst cleaning movable type with ether, he noticed that the evaporating fluid would leave the metal type cold to the touch. Harrison's first mechanical ice-making machine began operation in 1851 on the banks of the Barwon River at Rocky Point in Geelong, Victoria, Australia.

In 1855 James Harrison patented an ether liquid-vapor compression refrigeration system, which used a compressor to force the refrigeration gas to pass through a condenser, where it cooled down and liquefied.

A brewery became interested in Harrison's device and he was asked to adapt it so that it would cool beer. The result was the first practical use of a refrigeration machine. Harrison's system was almost immediately taken up by the brewing and meat-packing industries of Geelong.

The first industrial refrigeration system using gaseous ammonia dissolved in water was developed by Ferdinand Carré of France in 1859 and patented in 1860. His design was based on the gas–vapour system of James Harrison.

In 1862 Carré exhibited his ice-making machine at the Universal London Exhibition, producing an output of 200 kilograms (440 lb) per hour.

Carré's ice-making device

In early 1870s an engineering professor at the Technological University Munich in Germany, Carl von Linde, published articles in the Bavarian Industry and Trade Journal describing his research findings in the area of refrigeration.

Von Linde's first refrigeration system used dimethyl ether as the refrigerant and was built by Maschinenfabrik Augsburg (now MAN AG) for the Spaten Brewery in 1873.

In 1876 Von Linde patented equipment to liquefy air using the Joule Thomson expansion process and regenerative cooling. Von Linde's improved method of liquefying gases such as ammonia, sulfur dioxide and methyl chloride as refrigerants was widely used for that purpose until the late 1920s.

Ammonia is a poisonous gas and occasionally, one would leak, causing a minor emergency. Though the ammonia systems were too dangerous for domestic use, they could still be used in ship's holds, and within a decade of von Linde's discovery, refrigerated ships were carrying Australian, New Zealand and Argentinean exports to Europe. Ammonia is still in wide use as a refrigerant in industrial applications.

The first attempt to ship refrigerated meat from the souhern hemisphere was made when the Northam sailed from Australia to England in 1876; however the refrigeration machinery broke down en route and so the cargo was lost.

In 1880 a Director of the New Zealand and Australian Land Company (NZALC), William Soltau Davidson convinced the owners of the Dunedin to refit the sailing ship with a Bell-Coleman compression refrigeration machine, cooling the entire hold. On February 15, 1882, the Dunedin left New Zealand with 4331 mutton, 598 lamb and 22 pig carcasses, 2,226 sheep tongues. 250 kegs of butter, chicken, hare, pheasant and turkey.

The Dunedin loading at Port Chalmers in 1882.

The Dunedin arrived in London a little over three months after setting sail. Carcasses were sold at the Smithfield market over the following fortnight by John Swan and Sons. The success of the shipment effectively launched the refrigerated meat industry.

World Refrigeration Day is an international awareness campaign to raise the profile of the refrigeration, air-conditioning and heat-pump sector and focuses attention on the significant role that the industry and its technology play in modern life and society. Held annually on June 26, it was established by the World Refrigeration Day Secretariat in Derbyshire, England.

The day was chosen to celebrate the birth date of William Thomson on June 26, 1824. Thomson formed the first and second laws of thermodynamics and was made Lord Kelvin in 1892 in recognition of his achievements in thermodynamics. Absolute temperatures are stated in units of kelvin in his honor. The existence of a lower limit to temperature (absolute zero) was known before his work, but Lord Kelvin found its correct value as approximately −273.15 degree Celsius or −459.67 degree Fahrenheit.

Sources Europress Encyclopedia, The Independent

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