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SEMINAR

ON

“VAPOUR COMPRESSION REFRIGERATION”

SRI VENKATESHWARA

COLLEGE OF

ENGINEERING

SUBMITTED TO: SUBMITTED BY:

MR.SENTHIL KUMAR S.JAGADEESAN

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

*

*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 Capacity The 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 = 3.5kW

Ice 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 CondenserExpansion

Valve

Types of Refrigeration

System

Refrigeration System

Vapour Compression Refrigeration

System

Vapour Absorption

Refrigeration System

11

Type of Refrigeration

Vapour Compression Refrigeration

Refrigeration cycle

Condenser

Evaporator

High

Pressure

Side

Low

Pressure

Side

CompressorExpansion

Device

12

3

4

12

Type of Refrigeration

Vapour Compression Refrigeration

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

12

3

4

13

Type of Refrigeration

Vapour Compression Refrigeration

Refrigeration cycle

The superheated vapour enters the

compressor where its pressure is

raised

Condenser

Evaporator

High

Pressure

Side

Low

Pressure

Side

CompressorExpansion

Device

12

3

4

14

Type of Refrigeration

Vapour Compression Refrigeration

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

12

3

4

15

Type of Refrigeration

Vapour Compression Refrigeration

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

12

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.

16

17

Seminar

on

“Vapour Compression

Refrigeration”

THANK YOU

FOR YOUR ATTENTION