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Welcome to Our
Cold Rooms / fridges & Freezers Catering Equipment Website
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Some More General Cold Rooms / Fridges and Freezers Information Below |
A refrigerator (often called a "fridge" for short) is a
cooling appliance comprising a thermally insulated
compartment and a mechanism to transfer heat from it to the
external environment, cooling the contents to a temperature
below ambient. Refrigerators are extensively used to store
foods which deteriorate at ambient temperatures; spoilage
from bacterial growth and other processes is much slower at
low temperatures. A device described as a "refrigerator"
maintains a temperature a few degrees above the freezing
point of water; a similar device which maintains a
temperature below the freezing point of water is called a
"freezer". The refrigerator is a relatively modern invention
amongst kitchen appliances. It replaced the common icebox
which had been placed outside for almost a century and a
half prior, and is sometimes still called by the original
name "icebox".
Freezers keep their contents, usually foods, frozen. They
are used both in households and for commercial use. Most
freezers operate at around -18 °C (0 °F). Domestic freezers
can be included as a compartment in a refrigerator, sharing
the same mechanism or with a separate mechanism, or can be
standalone units. Domestic freezers are generally upright
units, resembling refrigerators, or chests, resembling
upright units laid on their backs. Many modern freezers come
with an icemaker.
Commercial fridge and freezer units, which go by many other
names, were in use for almost 40 years prior to the common
home models. They used toxic ammonia gas systems, making
them unsafe for home use. Practical household refrigerators
were introduced in the 1915 and gained wider acceptance in
the United States in the 1930s as prices fell and non-toxic,
non-flammable synthetic refrigerants such as Freon or R-12
were introduced. It is notable that while 60% of households
in the US owned a refrigerator by the 1930s, it was not
until 40 years later, in the 1970s, that the refrigerator
achieved a similar level of penetration in the United
Kingdom
Before the invention of the refrigerator, icehouses were
used to provide cool storage for most of the year. These
structures were mainly built and used in ancient Persia
(Iran). Placed near freshwater lakes or packed with snow and
ice during the winter, they were once very common. Using the
environment to cool foodstuffs is still common today. On
mountainsides run off from melting snow higher up is a
convenient way to cool drinks, and during the winter months
simply placing one's milk outside one's window is sufficient
to greatly extend its useful life.
The first known artificial refrigeration was demonstrated by
William Cullen at the University of Glasgow in 1748, 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 1857, Australian James Harrison introduced
vapor-compression refrigeration to the brewing and meat
packing industries. The absorption refrigerator was invented
by Baltzar von Platen and Carl Munters in 1922, while they
were still students at the Royal Institute of Technology in
Stockholm, Sweden. It became a worldwide success and was
commercialized by Electrolux. Other pioneers included
Charles Tellier, David Boyle, and Raoul Pictet.
A Monitor-style (General Electric format) refrigerator, more
like an icebox with its refrigerating mechanisms on top.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. His U.S. patents, issued in 1895 and 1908, 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 cost at the time.
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 a substantial amount of
heat, was placed above the cabinet, and surrounded with a
decorative ring. Over 1,000,000 units were produced. These
refrigerators used either sulfur dioxide or methyl formate
as a refrigerant. Many units are still functional today.
Older U.S. refrigerator model, with freezer compartmentThe
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.
Refrigerators used to consume more energy than any other
home appliance, but in the last twenty years, great strides
have been made to make refrigerators more energy efficient.
Current models that are Energy Star qualified use 50 percent
less energy than models made before 1993. [2]
Early refrigerator models (1916 and on) featured a cold
compartment for ice cube trays. Successful processing of
fresh vegetables through freezing began in the late 1920s by
the Postum Company (the forerunner of General Foods) which
had acquired the technology when it bought the rights to
Clarence Birdseye’s successful fresh freezing methods.
The first successful example of the benefits of frozen foods
occurred when General Foods heiress Marjorie Merriweather
Post (then wife of Joseph E. Davies, United States
Ambassador to the Soviet Union ) deployed commercial grade
freezers to Spasso House (US Embassy) in Moscow in advance
of the Davies’ arrival. Post, fearful of the food processing
safety observed in the USSR, then fully stocked the freezers
with product processed from General Foods Birdseye unit. The
frozen food stores allowed the Davies’ to lavishly entertain
and serve fresh frozen foods that would otherwise be out of
season. Upon returning from Moscow, Post (who resumed her
maiden name after divorcing Davies) directed General Foods
to market frozen product to upscale restaurants.
Introduction of home freezer units occurred in the United
States in 1940, and frozen foods began to make the
transition from luxury to necessity.
The invention of the refrigerator has allowed the modern
family to purchase, store, freeze, prepare and preserve food
products in a fresh state for much longer periods of time
than was previously possible. For the majority of families
without a sizeable garden in which to grow vegetables and
raise livestock, the advent of the refrigerator along with
the modern supermarket led to a vastly more varied diet and
improved health resulting from improved nutrition. Dairy
products, meats, fish, poultry and vegetables can all be
kept refrigerated in the same space within the kitchen
(although raw meat should be kept separate from other
foodstuffs for reasons of hygiene).
The refrigerator allows families to consume more salads,
fresh fruits and vegetables during meals without having to
own a garden or an orchard. Exotic foodstuffs from far-off
countries that have been imported by means of refrigeration
can be enjoyed in the home because of the availability of
domestic refrigeration.
The luxury of freezing allows households to purchase more
foods in bulk that can be eaten at leisure while the bulk
purchase provides cost savings (see economies of scale). Ice
cream, a popular commodity of the 20th century, was
previously only available by traveling long distances to
where the product was made fresh and had to be eaten on the
spot. Now it is a practically ubiquitous food item. Ice
on-demand not only adds to the enjoyment of cold drinks, but
is useful in first-aid applications, not to mention cold
packs that can be kept frozen for picnics or in case of
emergency.
Early freezer units accumulated ice crystals around the
freezing units. This was a result of humidity introduced
into the units when the doors to the freezer were opened.
This build up of frost required periodic thawing of the
units to maintain their efficiency. Advances in frost-free
refrigeration eliminating the thawing task were introduced
in the 1950s. Also, early units featured freezer
compartments located within the larger refrigerator, and
accessed by opening the refrigerator door, and then the
smaller internal freezer door; units featuring entirely
separate freezer compartment were introduced in the early
1960s, becoming the industry standard by the middle of that
decade.
Later advances included automatic ice units and self
compartmentalized freezing units.
An increasingly important environmental concern is the
disposal of old refrigerators - initially because of the
freon coolant damaging the ozone layer, but as the older
generation of refrigerators disappears it is the destruction
of CFC-bearing insulation which causes concern. Modern
refrigerators usually use a refrigerant called HFC-134a
(1,2,2,2-tetrafluoroethane) instead of freon, which has no
ozone layer depleting properties.
Disposal of discarded refrigerators is regulated, often
mandating the removal of doors: children playing
hide-and-seek have been asphyxiated while hiding inside a
discarded refrigerator. This was particularly true for the
older models that had latching doors. More modern units use
a magnetic door gasket to hold the door sealed but can
actually be pushed open from the inside. However, children
can be unwittingly harmed by hiding inside any discarded
refrigerator
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