necessity and applications of refrigeration

7/25/2019 Necessity and Applications of Refrigeration

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Necessity and applications of refrigera


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Zeroth Law of Thermodynamics. When two systemin thermal equilibrium with a third system, then

systems are also in thermal equilibrium with one This law provides the basis of temperature measurem

First Law of Thermodynamics. The heat and mechaare mutually convertible. "ccordin# to this law, whe

system under#oes a thermodynamic cycle, the transfer is equal to the net wor! transfer. $n other wcyclic inte#ral of heat transfer is equal to the cyclic wor! transfers.

%athematically, & '( ) & 'W


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The ener#y can neither created nor destroyed throbe transformed from one form to another.

"ccordin# to this law when a system under#oes a state *or a thermodynamic process+, then both heaand wor! transfer ta!es place.

The net ener#y transfer is stored with in the syst!nown as stored ener#y or total ener#y of the system

%athematically, '( 'W ) d-


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Heat Engine, Heat Pump, Refrigerator


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nits of /efri#eration

The practical unit of refri#eration is e0pressed in1tonne of refri#eration2 *brie3y written as T/+.

" tonne of refri#eration is de4ned as the arefri#eration e5ect produced by the uniform meltitone *6777 !#+ of ice from and at 789 in :; hours. latent heat of ice is ==> !?@!#, therefore one

refri#eration,

$n actual practice, one tone of refri#eration is ta!en ae uivalent to :67 ! @min or =.> !W *i.e. =.> ! s+.


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Applications

"pplications of refri#eration in Food processin#, preservation and distribution

9hemical and process industries


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Storage of Raw Fruits and Vegetables

$t is wellA!nown that some bacteria are respode#radation of food, and enBymatic processin# caus

of the fruits and ve#etables.The #rowth of bacteria and the rate of enBymatic

are reduced at low temperature.


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$n case of fruits andve#etables, the use

of refri#eration startsri#ht after harvestin#to remove the postAharvest heat,transport in

refri#erated transportto the cold stora#e orthe processin# plant.


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%eat and poultry

Cairy Droducts Eul! mil! cooler is a lar#e refri#erated tan! that cools it be

to 6>89. Then it is transported to dairy farms, where it is pDasteuriBation involves heatin# it to =89 and holdin# it attemperature for :7 seconds. Thereafter, it is cooled to = to

Eevera#es

Droduction of beer, wine and concentrated fruit Guices reqrefri#eration. The taste of many drin!s can be improved bthem cold or by addin# ice to them.

9andy se of chocolate in candy or its coatin# with chocolate req

settin# at >A6789 otherwise it becomes stic!y

Drocessin# and distribution of froBen foodA :> to A:789

A li ti f fi ti


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Applications of refrigerationin chemical & process industries

789 with refri#eration capacities as hi#h as

Tons of /efri#eration *T/+ are used for separation of #fractional distillation.

9ondensation of Hases -ase in transportation li!e amLDH

Cehumidi4cation of "ir Low humidity air is required

pharmaceutical industries. $t is also required for air liplants. This is also required to prevent static electriciprevents short circuits in places where hi#h volta#es


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9oolin# for preservation %any compounds decomporoom temperature or these evaporate at a very fast r

9ertain dru#s, e0plosives and natural rubber can be lon# periods at lower temperatures.


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Industrial applications

Laboratories

Drintin#

%anufacture of Drecision Darts

Te0tile $ndustry

Dharmaceutical $ndustries

Dhoto#raphic %aterial

Farm "nimals Kehicular "irAconditionin#


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(. "ir conditionin# involves

a+ 9ontrol of temperature b+ 9ontrol of humidity

c+ 9ontrol of air motion d+ 9ontrol of air purity

e+ "ll of the above

(. The purpose of industrial air conditionin# is to

a+ Drovide suitable conditions for products and processes

b+ Drovide at least a partial measure of comfort to wor!ers

c+ /educe ener#y consumption

d+ "ll of the above


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(. "ir conditionin# is required in the manufacture of parts to

a+ "chieve close tolerances b+ Drevent rust formation

c+ Drovide clean environment d+ "ll of the above

(. %odern electronic equipment require coolin# due

*a+ Cissipation of relatively lar#e amount of heat in small vo

b+ To prevent erratic behaviour

c+ To improve life

d+ "ll of the above


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(. Iuman bein#s need air conditionin# as

a+ They continuously dissipate heat due to metabolic activit

b+ Eody re#ulatory mechanisms need stable internal tempe

c+ -Jciency improves under controlled conditions

d+ "ll of the above

(.

necessity and applications of refrigeration

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