Refrigeration&Air Conditioning

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Technical Seminar Presentation - 2004

Presented By : Manmatha Kumar Giri

Technical Seminar Technical Seminar onon

Refrigeration & Air ConditioningRefrigeration & Air Conditioning

Presented by

Manmatha Kumar Giri

EE200113363

Under the Guidance of

Mr. Debashisha Jena



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INTRODUCTION• The electrical energy is utilized by

converting it into one form or other for

getting suitable output from it.

• The utilization electrical energy for the

refrigeration and air conditioning is fast

replacing the old methods.



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WHAT IS REFRIGERATION &

AIR CONDITIONING ?• The process of reducing the temperature of a body

from the general level of temperature of surroundings

is called refrigeration.• Air-conditioning means control of

temperature,humidity,purity and movement of air.

• The working conditions and comfort for human

beings is improved by air-conditioning.• The temperature is brought down during summer and

increased during winter without causing any discount.



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REFRIGERATOR

• This is the machine by which the

temperature of substances is lowered bystoring them in this machine.



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PRINCIPLE

• A refrigerator works onthe principle of coolingcaused by evaporation.

• when we dip our finger in petrol or spirit,and thefinger is taken outcooling is felt. This is

because when petrol or

spirit evaporates it drawsheat from the finger thuscooling it.



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REFRIGERANT

• The refrigerant is generally a gas which

circulated through different stages to extractthe heat from the substances.

• The various refrigerants used are carbon

dioxide(CO2),sulphur

dioxide(SO2),ammonia(NH3),Freon(F-12)

and methyl chloride etc.


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VAPOUR COMPRESSION CYCLE• The main purpose of vapour

compression cycle is to removeheat from the refrigerant by

putting it into a stage for reuse.• The various stages are

1.compression

2.condension

3.expansion

4.evaporation



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APPLICATION• The vapour compression refrigeration cycle is

employed for the following purposes

– Domestic refrigerator,

– Water cooler,

– Air conditioner,

– Ice plant,

– cold storage etc.



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DOMESTIC REFRIGERATOR • The actual lay out of domestic refrigerator

is shown in figure below.



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ELECTRICAL CIRCUIT OF

REFRIGERATOR • The main parts of the electrical

circuit are shown in figure

below• The various parts are

1. motor compressor unit

2. starting relay

3. thermostat4. overload protector

5. cabinet light

6. drier assembly.



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MOTOR COMPERESSOR UNIT• The motor is a single phase capacitor start

motor.

• The actual capacity of the motor depends uponthe size of the refrigerator.

• But generally the horsepower of motors varies

from 7/32 H.P. to 1/8 H.P.• Mostly the motor and compressor are in one unitand is known a sealed unit.



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STARTING RELAY

• The motor is operated by this relay which isalso called motor

protective relay.• It essentially consists

of a plunger on whicha coil is wound .

• The figure belowshows thearrangement:



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THRMOSTAT• A thermostatic switch

is used on all thehousehold refrigerators

by which thetemperature iscontrolled, and it iscalled thermostat.

• The construction of a

thermostat used in arefrigerator is shown infigure below:


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OVERLOAD PROTECTOR • This is a thermal device which opens the

circuit of the motor when overloaded and

is called overload protector.• The figure below shows the enlarged view

of a overload protector.



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CABINET LIGHT

• This circuit contains a lamp and a switch.

• The switch is called door switch and soinstalled that when the door is closed,the

bulb remains off.

• When the door is opened, the bulb remainson.



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DRIER ASSEMBLY

• This assembly is not employed on all the

domestic refrigerators.• This is a high resistance wire passing

around the drier to remove the moisture

from the refrigerator.• This is connected across the supply by the

thermostat.



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AIR-CONDITIONER • The room air conditioner is used to condition the

air of a particular space occupied by the human

beings i.e. office, room etc.• It has automatic operation to control and maintain

the humidity of air.

• There are two parts divided by a partition with a

small opening at the top as

1.outdoor part

2.indoor part



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AIR-CONDITIONER • The complete operation of

an air conditioner can be

studied under these sub

headings-

1.vapour compression cycle

2.air circulation

3.electrical circuit

• The figure below shows a

room air conditioner



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CONCLUSION• The electrical energy is utilised by converting it into

one form or the other form for getting suitable

output from it.• The utilization of electrical energy for the

refrigeration and air conditioning is fast replacingthe old methods.

• Refrigeration and Air Conditioning has become anecessity in every sphere of human utility andindustrial set-ups.



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Thank You…

Refrigeration&Air Conditioning

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