Refrigerator

Mahakal Institute of Tech. & Science,Ujjain

Refrigerator

Submitted By: Prakhar Pandey

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Contents

o Introductiono Historyo The Basic Principleo Components of Refrigerator & Workingo Concept of Refrigerant

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Introduction

What is a Refrigerator

The mechanism used for removing heat from a substance under controlled conditions.

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History

o William Cullen, the first to conduct experiments into artificial refrigeration.

o Oliver Evans, designed the first refrigeration machine for practical purpose.

William Cullen1755

Oliver Evans1834

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The Basic Principle

Basic principle of refrigeration is simple-Just pass a colder liquid continuously around the object which is to be cooled. This will take heat out from the object.

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Components of Refrigerator

It has got 4 main components; o Compressor o Condenser o Evaporator ando Throttling Device.

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Throttling Device

o Throttling device is an obstruction to the flow.o It is responsible for the production of cold liquid.o It causes the pressure and temperature drop in high pressure

liquid.

Length = 2mDiameter = 0.6mm(www.learningengineering.com)

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Evaporator - Heat Absorption Process

o The Evaporator is a heat exchanger required to carry the cold refrigerant over the body.

o Here, the refrigerant further evaporates and transforms into pure vapor.

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Compressor

o Usually hermetically sealed reciprocating type with proper sealing is used.

o Compressor will raise the pressure back to its initial value.o Now the refrigerant is high pressure vapor.

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Condenser

o This heat exchanger is fitted outside refrigerator.

o Here, vapor will get condensed to liquid and temperature will come down to normal level.

o Now the refrigerant is high pressure liquid.

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Refrigerant concept

o Refrigerant = Ro Notations = CmHnFpClq

o In which, (n + p + q) = 2m+2 (for saturated hydrocarbon) (n + p + q) = 2m (for unsaturated hydrocarbon)

R(m)(n)(p)

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Cntd.

Presently Working substance is R12, R12

is CFC (chloro-floro carbon).

B’use of the ozone layer depletion problem, alternatives such as following are also used in place of R12-• R290, viz., Propane C3H8)• R134a viz., Tetra-

fluoroethene (C2H2F4)• R600a, viz., Isobutane

(C4H10)

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Thank you

Q & A