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how it works what is advantages and dis advantages ., how will affect on human health

2006-11-20 19:23:01 · 4 answers · asked by sreeperum srinu 1 in Education & Reference Homework Help

4 answers

A refrigerator (often called a "fridge" for short) is an appliance for the storage and preservation of perishable food; food kept in a refrigerator lasts longer than that left at room temperature as the cold inhibits bacterial growth. A refrigerator maintains a cold temperature above the freezing point of water; commonly refrigerators are used in conjunction with freezers, which maintain temperatures below freezing, or a refrigerator may have an integrated freezer compartment. The refrigerator is a relatively modern invention amongst kitchen appliances. It replaced the common icebox which had been a household item for almost a century and a half prior, and is sometimes still called by the name "icebox".

Commercial units, which go by many other names, were in use for almost 40 years prior to the common home models. The fact that they operated with toxic ammonia gas systems made them unsafe for home use. Practical household refrigerators were introduced in the 1920s and gained wider acceptance in the 1930s as prices fell and non-toxic, nonflammable synthetic refrigerants, such as Freon or R-12 refrigerants were introduced.

the advantages and disadvantages u can look straight to my source... it has many information... i hope this helps... good luck ^^

2006-11-20 19:43:02 · answer #1 · answered by xjellybeAnsx 2 · 0 0

The first known artificial refrigeration was demonstrated by William Cullen at the University of Glasgow in the mid 1700s, and relied on the vapor-compression refrigeration process explained by Michael Faraday. Between 1805, when Oliver Evans designed the first refrigeration machine that used vapor instead of liquid, and 1902 when Willis Haviland Carrier demonstrated the first air conditioner, scores of inventors contributed many small advances in cooling machinery. In 1850 or 1851, Dr. John Gorrie demonstrated an ice maker. In 1856, James Harrison introduced vapor-compression refrigeration to the brewing and meat packing industries. Other pioneers included Charles Tellier, David Boyle, and Raoul Pictet.

At the start of the 20th Century, about half of households in the United States relied on melting ice (and an icebox) to keep food cold, while the remaining half had no cooled storage at all. The ice used for household storage was expensive because ice had to be cut from winter ponds (or mechanically produced), stored centrally until needed, and delivered regularly.

In a few exceptional cases, mechanical refrigeration systems had been adapted by the start of the 20th century for use in the homes of the very wealthy, and might be used for cooling both living and food storage areas. One early system was installed at the mansion of Walter Pierce, an oil company executive.[1]

Marcel Audiffren of France championed the idea of a refrigerating machine for cooling and preserving foods at home, and he received U.S. Patents #551,107 (in 1895) and #898,400 (in 1908, with Albert Sigrun). These patents were purchased by the American Audiffren Refrigerating Machine Company. Machines based on Audiffren's sulfur dioxide process were manufactured by General Electric in Fort Wayne, Indiana and marketed by the Johns Manville Company. The first unit was sold in 1911. Audiffren machines were expensive, selling for about $1,000 — about twice as much as an automobile.

General Electric sought to develop refrigerators of its own, and in 1915 the first Guardian unit was assembled in a back yard wash house as a predecessor to the Frigidaire. In 1916 Kelvinator and Servel came out with two units among a field of competing models. This number increased to 200 by 1920. In 1918 Kelvinator had a model with automatic controls.

These home units usually required the installation of the mechanical parts, motor and compressor, in the basement or an adjacent room while the cold box was located in the kitchen. There was a 1922 model that consisted of a wooden cold box, water-cooled compressor, an ice cube tray and a 9 cubic foot compartment for $714. (A 1922 Model-T Ford cost about $450.) In 1923 Frigidaire introduced the first self-contained unit. About this same time porcelain covered metal cabinets began to appear. Ice cube trays were introduced more and more during the 1920s; up to this time freezing was not a function of the modern refrigerator.

The first refrigerator to see widespread use was the General Electric "Monitor-Top" refrigerator introduced in 1927. The compressor assembly, which emitted substantial amount of heat, was placed above the cabinet, and surrounded with a decorative ring. Over 1,000,000 units were produced. This refrigerator used sulfur dioxide refrigerant. Many units are still functional today.

The introduction of freon expanded the refrigerator market during the 1930s, and freezer units became a little more common and requested during the 1940s. Home units did not go into mass production until after WWII. The 1950s and 60s saw technical advances like automatic defrosting and automatic ice making. Developments of the 1970s and 80s brought about more efficient refrigerators, and environmental issues banned the use of CFC (freon) refrigerants used in sealed systems.

2006-11-21 03:46:23 · answer #2 · answered by Pooja Bedi 3 · 0 0

You mean a refrigerator. Now start doing your homework by thinking of how it would affect your life and your daily schedule/activities if there were no refrigerators in the world.

2006-11-21 03:29:06 · answer #3 · answered by gettin'real 5 · 0 0

what's a

refregerator??

2006-11-21 03:27:03 · answer #4 · answered by COOKIE 5 · 0 0

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