SEMINAR ON “VAPOUR COMPRESSION REFRIGERATION”

GUIDED BY:- PREPARED BY:-Mr. Devendra Bhandari Ujjwal Nautiyal B.Tech(ME) II sem 1014366(38)

Refrigeration

Vapour Compression Refrigeration

Refrigeration is a process of removal of heat from a substance at a temperature lower than the surrounding with the aid of external work.

In a refrigeration system, the rate at which the heat is absorbed in a cycle from the interior space to be cooled is called Refrigerating Effect.

Refrigeration

*Refrigerant

*In a refrigerator, a medium called Refrigerant continuously extracts the heat from the refrigerator which is to be kept cool at temperatures less than the atmosphere & finally rejects to it.

*Refrigerant acts as a heat exchange medium.

*e.g.- Ammonia, Freon, Methyl Chloride, Carbon dioxide, Isobutane.

Unit of Refrigeration & Ice making CapacityThe capacity of a refrigeration system is expressed

in tons of refrigeration which is the unit of refrigeration.

A ton of refrigeration is the quantity of heat absorbed in order to form one ton of ice in 24 hours when the initial temperature of water is 0°c.

1 Ton of Refrigeration = 210 kJ/min = 3.5kWIce making capacity is the capacity of the

refrigerating system to make ice beginning from water to solid.

S.I. unit of ice making capacity is kg/hr.

Coefficient of Performance

The coefficient of performance(briefly written as C.O.P.) is the ratio of desired effect to the work input.

Mathematically,

(C.O.P.)refrigerator = Desired effect = Q2____

Work Input Q1-Q2

T1=Tsurr

Source T1

T2<Tsurr

Sink T2

R Work Input,W=Q1-Q2

Heat Absorbed, Q2

Heat Rejected, Q1

Refrigerator is a reversed heat engine.It extracts Q2 amount of heat from sink & releases Q1 amount of heat to source.Input—Work(Q1-Q2)Output– Heat

Refrigerator

PARTS OF REFRIGERATOR

Parts of Refrigerator

Evaporator Compressor Condenser Expansion Valve

Types of Refrigeration System

Refrigeration System

Vapour Compression Refrigeration System

Vapour Absorption Refrigeration System

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Type of Refrigeration

Vapour Compression Refrigeration

Ref ri gerat ion

Refrigeration cycle

Condenser

Evaporator

High Pressure

Side

Low Pressure

Side

CompressorExpansion Device

1 2

3

4

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Type of Refrigeration

Vapour Compression Refrigeration

/Refr iger ation

Refrigeration cycle

Low pressure liquid refrigerant in evaporator absorbs heat and changes to a gas

Condenser

Evaporator

High Pressure

Side

Low Pressure

Side

CompressorExpansion Device

1 2

3

4

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Type of Refrigeration

Vapour Compression Refrigeration

Ref ri gerat ion

Refrigeration cycle

The superheated vapour enters the compressor where its pressure is raised

Condenser

Evaporator

High Pressure

Side

Low Pressure

Side

CompressorExpansion Device

1 2

3

4

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Type of Refrigeration

Vapour Compression Refrigeration

Ref ri gerat ion

Refrigeration cycle

The high pressure superheated gas is cooled in several stages in the condenser

Condenser

Evaporator

High Pressure

Side

Low Pressure

Side

CompressorExpansion Device

1 2

3

4

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Type of Refrigeration

Vapour Compression Refrigeration

Ref ri gerat ion

Refrigeration cycle

Liquid passes through expansion device, which reduces its pressure and controls the flow into the evaporator

Condenser

Evaporator

High Pressure

Side

Low Pressure

Side

CompressorExpansion Device

1 2

3

4

Advantages Very mature technology. It has very less running cost. It has smaller size for the given capacity of refrigeration. It can be employed over a large range of temperatures. The C.O.P. is very high.

Disadvantages Many systems still use HCFC refrigerants, which

contribute to depletion of ozone layer. Initial cost is high. The prevention of leakage of refrigerant is the major

problem in vapour compression refrigeration.

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Advantages & Disadvantages of Vapour compression refrigeration

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Seminar on

“Vapour Compression Refrigeration”

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FOR YOUR ATTENTION