Project on Refrigerator and Ac

7/25/2019 Project on Refrigerator and Ac

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CONTENTS

History

Freezer

Commercial and domestic refrigerators

Styles of refrigerators

Production by country

General technical explanation

Features

Types of domestic refrigerators

Energy efficiency

Effect on lifestyle

Temperature zones and ratings
http://en.wikipedia.org/wiki/Refrigerator#Historyhttp://en.wikipedia.org/wiki/Refrigerator#Freezerhttp://en.wikipedia.org/wiki/Refrigerator#Commercial_and_domestic_refrigeratorshttp://en.wikipedia.org/wiki/Refrigerator#Styles_of_refrigeratorshttp://en.wikipedia.org/wiki/Refrigerator#Production_by_countryhttp://en.wikipedia.org/wiki/Refrigerator#General_technical_explanationhttp://en.wikipedia.org/wiki/Refrigerator#Featureshttp://en.wikipedia.org/wiki/Refrigerator#Types_of_domestic_refrigeratorshttp://en.wikipedia.org/wiki/Refrigerator#Energy_efficiencyhttp://en.wikipedia.org/wiki/Refrigerator#Effect_on_lifestylehttp://en.wikipedia.org/wiki/Refrigerator#Temperature_zones_and_ratingshttp://en.wikipedia.org/wiki/Refrigerator#Freezerhttp://en.wikipedia.org/wiki/Refrigerator#Commercial_and_domestic_refrigeratorshttp://en.wikipedia.org/wiki/Refrigerator#Styles_of_refrigeratorshttp://en.wikipedia.org/wiki/Refrigerator#Production_by_countryhttp://en.wikipedia.org/wiki/Refrigerator#General_technical_explanationhttp://en.wikipedia.org/wiki/Refrigerator#Featureshttp://en.wikipedia.org/wiki/Refrigerator#Types_of_domestic_refrigeratorshttp://en.wikipedia.org/wiki/Refrigerator#Energy_efficiencyhttp://en.wikipedia.org/wiki/Refrigerator#Effect_on_lifestylehttp://en.wikipedia.org/wiki/Refrigerator#Temperature_zones_and_ratingshttp://en.wikipedia.org/wiki/Refrigerator#History


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Refrigerator

refrigerator!collo"uially fridge# is a common household appliancethat

consists of a thermally insulatedcompartment and a heat pump!mechanical$

electronic$ or chemical# that transfers heat from the inside of the fridge to its

external en%ironment so that the inside of the fridge is cooled to a temperature

belo& the ambient temperature of the room' Refrigeration is an essential food

storage techni"ue in de%eloped countries' (o&er temperatures in a confined%olume lo&ers the reproduction rate ofbacteria$ so the refrigerator reduces the

rate of spoilage'

refrigerator maintains a temperature a fe& degrees abo%e the freezing pointof

&ater' )ptimum temperature range for perishable food storage is * to + ,C

!*- to ./ ,F#'0/1 similar de%ice that maintains a temperature belo& the freezing

point of &ater is called a freezer' The refrigerator replaced the icebox$ &hich&as a common household appliance for almost a century and a half prior' For

this reason$ a refrigerator is sometimes referred to as anicebox'

History

2efore the in%ention of the refrigerator$ icehouses&ere used to pro%ide cool

storage for most of the year' Placed near fresh&ater la3es or pac3ed &ith sno&

and ice during the &inter$ they &ere once %ery common' 4atural means are still

used to cool foods today' )n mountainsides$ runoff from melting sno& is a
http://en.wikipedia.org/wiki/Household_appliancehttp://en.wikipedia.org/wiki/Thermal_insulationhttp://en.wikipedia.org/wiki/Heat_pumphttp://en.wikipedia.org/wiki/Food_preservationhttp://en.wikipedia.org/wiki/Food_preservationhttp://en.wikipedia.org/wiki/Bacteriahttp://en.wikipedia.org/wiki/Spoilagehttp://en.wikipedia.org/wiki/Freezing_pointhttp://en.wikipedia.org/wiki/Refrigerator#cite_note-bbc.co.uk-1http://en.wikipedia.org/wiki/Iceboxhttp://en.wikipedia.org/wiki/Icehouse_(building)http://en.wikipedia.org/wiki/Household_appliancehttp://en.wikipedia.org/wiki/Thermal_insulationhttp://en.wikipedia.org/wiki/Heat_pumphttp://en.wikipedia.org/wiki/Food_preservationhttp://en.wikipedia.org/wiki/Food_preservationhttp://en.wikipedia.org/wiki/Bacteriahttp://en.wikipedia.org/wiki/Spoilagehttp://en.wikipedia.org/wiki/Freezing_pointhttp://en.wikipedia.org/wiki/Refrigerator#cite_note-bbc.co.uk-1http://en.wikipedia.org/wiki/Iceboxhttp://en.wikipedia.org/wiki/Icehouse_(building)


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mechanical refrigeration unit in /9./based on E%ans8 original in%ention to

ma3e ice into cool air for yello& fe%erpatients' Gorrie8s mechanical

refrigeration unit recei%ed a patent in /9+/'091merican professor lexander C'

T&ining of Cle%eland$ )hio patented an early %aporAcompression refrigerator in

/9+* that &as fully capable of producing a ton of ice per day'0aco in /9-/'0//1:n /9-*$ the patent for this machine &as contracted by the

Columbus :ron >or3s$0/1a company ac"uired by the >' C' 2radley Co'$ &hich

produced the &orld8s first commercial iceAma3ers
http://en.wikipedia.org/wiki/Yellow_feverhttp://en.wikipedia.org/wiki/Refrigerator#cite_note-8http://en.wikipedia.org/wiki/Refrigerator#cite_note-9http://en.wikipedia.org/wiki/James_Harrison_(engineer)http://en.wikipedia.org/wiki/Scotlandhttp://en.wikipedia.org/wiki/Australiahttp://en.wikipedia.org/wiki/Ammoniahttp://en.wikipedia.org/wiki/Refrigerator#cite_note-10http://en.wikipedia.org/wiki/Ferdinand_Carr%C3%A9http://en.wikipedia.org/wiki/Francehttp://en.wikipedia.org/wiki/Refrigerator#cite_note-11http://en.wikipedia.org/wiki/Refrigerator#cite_note-12http://en.wikipedia.org/wiki/W._C._Bradley_Co.http://en.wikipedia.org/wiki/Yellow_feverhttp://en.wikipedia.org/wiki/Refrigerator#cite_note-8http://en.wikipedia.org/wiki/Refrigerator#cite_note-9http://en.wikipedia.org/wiki/James_Harrison_(engineer)http://en.wikipedia.org/wiki/Scotlandhttp://en.wikipedia.org/wiki/Australiahttp://en.wikipedia.org/wiki/Ammoniahttp://en.wikipedia.org/wiki/Refrigerator#cite_note-10http://en.wikipedia.org/wiki/Ferdinand_Carr%C3%A9http://en.wikipedia.org/wiki/Francehttp://en.wikipedia.org/wiki/Refrigerator#cite_note-11http://en.wikipedia.org/wiki/Refrigerator#cite_note-12http://en.wikipedia.org/wiki/W._C._Bradley_Co.


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Carl Paul Gottfried (inde$ ennobled in /9


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corrosi%e to the eyes and may cause loss of %ision$ painful s3in burns and

lesions$ or methyl formate$ &hich is highly flammable$ harmful to the eyes$ and

toxic if inhaled or ingested' any of these units are still functional today' These

cooling systems cannot legally be recharged &ith the hazardous original

refrigerants if they lea3 or brea3 do&n'

The introduction of Freonin the /orld >ar ::' The

/


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Home freezers as separate compartments !larger than necessary 5ust for ice

cubes#$ or as separate units$ &ere introduced in the ?nited States in /


8/13

harmful replacement for RA/$ RA/*.a !tetrafluoroethane#$ has been in common

use since /


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SideAbyAside style introduced by manain /


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Dapor Compression Cycle O ; hot compartment !3itchen#$ 2; cold

compartment !refrigerator box#$ :; insulation$ /; Condenser$ ; Expansion %al%e$

*; E%aporator unit$ .; Compressor

n Embracocompressor and fanAassisted condenser coil

%apor compression cycle is used in most household refrigerators$ refrigeratorO

freezers and freezers' :n this cycle$ a circulating refrigerant suchas R/*.aenters a compressor as lo&Apressure %apor at or slightly abo%e the

temperature of the refrigerator interior' The %apor is compressed and exits the

compressor as highApressure superheated %apor' The superheated %apor tra%els

under pressure through coils or tubes comprising the condenser$ &hich are

passi%ely cooled by exposure to air in the room' The condenser cools the %apor$

&hich li"uefies' s the refrigerant lea%es the condenser$ it is still under pressure

but is no& only slightly abo%e room temperature' This li"uid refrigerant is

forced through a metering or throttling de%ice$ also 3no&n as an expansion

%al%e !essentially a pinAhole sized constriction in the tubing# to an area of much

lo&er pressure' The sudden decrease in pressure results in explosi%eAli3e flash

e%aporation of a portion !typically about half# of the li"uid' The latent heat

absorbed by this flash e%aporation is dra&n mostly from ad5acent stillAli"uid

refrigerant$ a phenomenon 3no&n as auto-refrigeration' This cold and partially

%aporized refrigerant continues through the coils or tubes of the e%aporator unit'
http://en.wikipedia.org/wiki/Embracohttp://en.wikipedia.org/wiki/R134ahttp://en.wikipedia.org/wiki/Embracohttp://en.wikipedia.org/wiki/R134a


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fan blo&s air from the refrigerator or freezer compartment !@box air@# across

these coils or tubes and the refrigerant completely %aporizes$ dra&ing further

latent heat from the box air' This cooled air is returned to the refrigerator or

freezer compartment$ and so 3eeps the box air cold' 4ote that the cool air in the

refrigerator or freezer is still &armer than the refrigerant in the e%aporator'

Refrigerant lea%es the e%aporator$ no& fully %aporized and slightly heated$ and

returns to the compressor inlet to continue the cycle'

n absorption refrigerator&or3s differently from a compressor refrigerator$

using a source of heat$ such as combustionof li"uefied petroleum gas$ solar

thermal energyor an electric heating element' These heat sources are much

"uieter than the compressor motor in a typical refrigerator' fan or pump might

be the only mechanical mo%ing partsJ reliance on con%ection is considered

impractical'

The Peltier effectuses electricity to pump heat directlyJ this type of refrigerator

is sometimes used for camping$ or &here noise is not acceptable' They can be

totally silent !if they don8t include a fan for air circulation# but are less energyA

efficient than other methods'

)ther uses of an absorption refrigerator !or @chiller@# include large systems used

in office buildings or complexes such as hospitals and uni%ersities' These large

systems are used to chill a brine solution that is circulated through the building'

any modern refrigeratorNfreezers ha%e the freezer on top and the refrigeratoron the bottom' ost refrigeratorAfreezersexcept for manual defrost models or

cheaper unitsuse &hat appears to be t&o thermostats' )nly the refrigerator

compartment is properly temperature controlled' >hen the refrigerator gets too

&arm$ the thermostat starts the cooling process and a fan circulates the air

around the freezer' 6uring this time$ the refrigerator also gets colder' The

freezer control 3nob only controls the amount of air that flo&s into the

refrigerator %ia a damper system'0/


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the freezer temperature &ill ha%e no effect on the refrigerator temperature' The

freezer control may also be ad5usted to compensate for any refrigerator

ad5ustment'

This means the refrigerator may become too &arm' Ho&e%er$ because only

enough air is di%erted to the refrigerator compartment$ the freezer usually reA

ac"uires the set temperature "uic3ly$ unless the door is opened' >hen a door is

opened$ either in the refrigerator or the freezer$ the fan in some units stops

immediately to pre%ent excessi%e frost build up on the freezer8s e%aporator coil$

because this coil is cooling t&o areas' >hen the freezer reaches temperature$ the

unit cycles off$ no matter &hat the refrigerator temperature is' Some

people0who?1recommend setting the refrigerator to maximum and the freezer to a

point &here one8s refrigerated food &on8t freeze' odern computerized

refrigerators do not use the damper system' The computer manages fan speed

for both compartments$ although air is still blo&n from the freezer'

fe& manufacturers$ such as Sub ero and Sun Frost$ offer dual compressor

models' These models ha%e separate freezer and refrigerator compartments that

operate independently of each other$ sometimes mounted &ithin a single

cabinet' Each has its o&n separate compressor$ condenser and e%aporator coils$

insulation$ thermostat$ and door' Typically$ the compressors and condenser coils

are mounted at the top of the cabinet$ &ith a single fan to cool them both'

This design$ &here no air passes bet&een the t&o compartments$ pro%ides for

more appropriate humidity le%els and much tighter temperature control in each

compartment' :t also re"uires much less energy to operate$ since each

compressor Q coolant system can be optimized for a specific temperature range'

Further$ opening the door of one compartment does not affect the temperature of

the air or humidity le%el in the other compartment' Thus$ it a%oids many of the

disad%antages of the much more common single compressor designs described

abo%e$ although at a higher initial cost' anufacturers of such designs argue
http://en.wikipedia.org/wiki/Wikipedia:Avoid_weasel_wordshttp://en.wikipedia.org/wiki/Wikipedia:Avoid_weasel_words


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that the increased cost is compensated o%er time due to reduced energy use and

less food &aste due to reduced spoilage

DRIEMS POLYTECHNIC

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Project on Refrigerator and Ac