(title unknown)

Kemampuan kulkas mengawetkan makanan bukannya karena benda ini sakti, lho! Sebenarnya, lemari es mampu mengeluarkan hawa dingin di dalamnya sehingga bakteri-bakteri pembusuk tidak bisa hidup dalam bahan makanan.

Berabad-abad lalu, sebelum lemari es ditemukan, orang-orang Romawi kuno mengawetkan makanan menggunakan es yang mereka angkut dari puncak gunung. Duh, terbayang kan repotnya. Untuk menyimpan makanan saja harus berlelah-lelah seperti itu.


Sementara di Meksiko, suku Aztek mengawetkan makanan menggunakan salju. Caranya, mereka menggali lubang berukuran besar. Lalu, bagian dasar dan sekelilingnya mereka lapisi dengan bilahan kayu atau jerami. Setelah itu, mereka mengisikan es atau salju ke dalamnya, lalu menutupnya lagi dengan jerami. Barulah mereka meletakkan makanan, kemudian menutupnya dengan rapat.Dengan cara ini, bahan makanan jadi lebih awet.

Penyimpanan makanan dengan cara ini biasanya dilakukan orang zaman dulu ketika musim dingin tiba. Ya, di musim salju kan sama sekali tak ada buah-buahan dan sayuran yang dapat mereka makan. Soalnya, kehidupan ketika itu benar-benar bergantung pada alam. Nah, berkat kulkas tradisional itu, makanan jadi awet dan penduduk tidak kekurangan makanan.

Karena menginginkan cara yang lebih praktis, di awal abad ke-18, orang-orang pintar di Inggris mulai memikirkan membuat lemari pendingin. Mereka merancang lemari es sedemikian rupa, dengan bentuk yang sama sekali tidak sedap dipandang. Ukurannya besaaaaar..., mungkin selebar pintu rumah. Terbuat dari besi kusam dan.... uh, berat banget. Pintunya terbuat dari besi, juga tebal, dan berat.


Berbagai percobaan mereka lakukan dan... berhasil. Lemari es pertama ini bisa mengeluarkan hawa dingin. Maka, orang-orang kaya di Inggris, di abad itu sudah memiliki kulkas di rumah masing-masing.

Akan tetapi para pencipta kaget luar biasa. Sekali waktu, ada peristiwa orang-orang yang berada di rumah pemilik lemari es, meninggal semua. Selidik punya selidik, mereka meninggal gara-gara kebocoran gas beracun yang digunakan untuk mendinginkan kulkas itu.

Maka, tahun 1929, gas ini diganti dengan gas tak beracun yang disebut freon. Akan tetapi, belakangan ketahuan juga bahwa freon menyebabkan kerusakan ozon pada atmosfer bumi. Freon ternyata tidak ramah lingkungan. Akhirnya, gas ini pun diganti juga dengan bahan lain yang sama-sama dapat mendinginkan, tetapi aman bagi manusia maupun lingkungan


+sebelum masehi
-1000 The Chinese cut and stored ice
-500 Egyptians and Indians made ice on cold nights by setting water out in earthenware pots
+sesudah masehi
-1700 In England, servants collected ice in the winter and put it into icehouses for use in the summer
-1720 Dr. William Cullen, a Scotsman, studied the evaporation of liquids in a vacuum
-1805 Oliver Evans of Pennsylvania, compressed ether machine, the machine is never built
-1820 Michael Faraday, a Londoner, liquified ammonia to cause cooling
-1834 Jacob Perkins, ether vapour compression cycle, Ice Making Machine
-1844 James Harrison of Australia invents compressed ether machine
-1850 Edmond Carre of France, invents an absorption process machine
-1852 William Thomson & James Prescott cooling increases in proportion to the pressure difference
-1855 Dr. John Gorrie builds compression refrigeration system based on Faraday's experiments.
-1856 James Harrison commissioned by a brewery to build a machine that cooled beer.
-1859 Ferdinand Carre of France, developed the first ammonia/water refrigeration machine
-1871 Carl von Linde of Germany published an essay on improved refrigeration techniques
-1873 Carl von Linde first practical and portable compressor refrigeration machine was built in Munich
-1874 Raoul Pictet of Switzerland, a compressor system using sulfur dioxide instead of ammonia
-1876 Carl von Linde, early models he used methyl ether, but changed to an ammonia cycle
-1878 von Linde starts Lindes Eismaschinen AG, (Society for Lindes Ice Machines), now Linde AG
-1881 Edmund J. Copeland and Arnold H. Gross start Leonard Refrigerator Company
-1894 Linde developed a new method (Linde technique) for the liquefaction of large quantities of air.
-1894 Linde AG installs refrigerator at the Guinness brewery in Dublin, Ireland
-1895 Carl von Linde produced large amounts of liquid air using the Thomson-Joule effect
-1901 Patent # 665,814 issued January 10, for a Refridgeator (Ice Box) invented by Henry Trost.
-1911 General Electric company unveiled a refrigerator invented by a French monk. Abbe Audiffren
-1913 Fred W. Wolf Jr.of the Domelre Company (DOMestic ELectric REfrigerator)
-1914 Leonard Refrigerator Company renamed Electro-Automatic Refrigerating Company
-1915 Alfred Mellowes starts Guardian Frigerato to build first self-container refrigerator for home use
-1916 Servel models compressors were generally driven by motors located in the basement
-1916 Henry Joy of Packard Motor Car Co. purchased the Fred W. Wolf refrigerator rights
-1918 Guardian Frigerato purchased by General Motors and renamed Frigidaire
-1918 Electro-Automatic Refrigerating Company renamed Kelvinator
-1920 there were some 200 different refrigerator models on the market.
-1922 Baltzar von Platen and Carl Munters introduce absorption process refrigerator
-1923 Kelvinator held 80 percent of the market for electric refrigerators
-1923 AB Arctic.begins production of refrigerators based on Platen-Munter's invention
-1925 Electrolux purchases AB Arctic and launches the 'D-fridge' on the world market
-1925 Steel and porcelain cabinets began appearing in the mid-20s
-1927 first refrigerator to see widespread use was the General Electric 'Monitor-Top' refrigerator.
-1930 first built-in refrigerator is launched by Electrolux
1931 Dupont produced commercial quantities of R-12, trademarked as Freon
-1931 the first air-cooled refrigerator introduced by Electrolux
-1932 Gibson, then owned by Frank Gibson, manufactured its own line of refrigerators.
-1934 an innovation, the Shelvador refrigerator, was introduced by the Crosley Radio Corporation
-1936 Albert Henne synthesizes refrigerant R-134a
-1937 more than 2 million Americans owned refrigerators.
-1939 refrigerator with one section for frozen food and a second for chilled food, introduced by G. E.
-1946 Mass production of modern refrigerators didn't get started until after World War II.
-1947 GE two-door refrigerator-freezer combination
-1955 80% of American homes now have refrigerators
-2005 A domestic refrigerator is present in 99.5% of American homes

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