A vapor compression cycle is used in most household refrigerators, refrigerator–freezers and freezers. Newer refrigerators may include automatic defrosting, chilled water, and ice from a dispenser in the door. Domestic refrigerators and freezers for food storage are made in a range of sizes.its includes Condenser. Condensation changes gas to a liquid form. ... Compressor. ... Evaporator. ... Expansion Valve.

1. Domestic
REFRIGERATION
SYSTEMS
Presented by
Binyamin Butt
2015-dt-009
Presented to SIR:
Eng. Mr. Saqib Manzoor

2. Refrigeration
The term refrigeration may be defined as
the process of removing heat from a
substance under controlled conditions.
It also includes the process of reducing
heat & maintaining the temp. of a body
below the general temp. of its
surroundings.

3. Contd….
In other words the refrigeration
means a continued extraction of
heat from a body whose temp is
already below the temp. of its
surroundings.

4. Refrigerator & Refrigerant
A refrigerator is a reversed heat engine or
a heat pump which takes out heat from a
cold body & delivers it to a hot body.
The refrigerant is a heat carrying medium
which during their cycle in a refrigeration
system absorbs heat from a low temp.
system & delivers it to a higher temp.
system.

5. Refrigerants use commonly
 Modern refrigerators usually use a
refrigerant called HFC-134a (1,1,1,2-
Tetrafluoroethane), which does not
deplete the ozone layer, instead
of Freon. A R-134a is now becoming
very uncommon in Europe. Newer
refrigerants are being used instead.

6. Refrigeration Cycle
In refrigeration system the heat is
being generally pumped from low
level to higher one & rejected at
that temp.
This rejection of heat from low
level to higher level of temp. can
only be performed with the help
of external work according to
second law of thermodynamics.

7. Refrigeration Cycle

8. Refrigeration Systems
• Vapour compression refrigeration system
• Vapour absorption refrigeration system
• Thermo electric refrigeration system

9. Every refrigeration cycle
components
• Each cycle of operation consists of the
four fundamental changes of state or
processes:-
 Expansion
 Evaporator
 Compression
 Condensation

10. Components of Vapour
Compression Systems

11. Vapour
compression
refrigeration
system

12. Compressor has two main
functions
 1st to maintain the refrigerant
flow within refrigeration cycle
 2nd is to create Pressure difference
within cycle

13. COMPRESSOR

14. Compressor
The low pressure & temp. refrigerant
from evaporator is drawn into the
compressor through the inlet or suction
valve , where it is compressed to a high
pressure & temp.
The high pressure & temp vapour
refrigerant is discharged into the
condenser through the delivery or
discharge valve.

15. CONDENSOR has two
main function
the main function is to cool down
refrigerant by putting out the heat
of refrigerant.
Change the Vapour refrigerant to
liquid refrigerant

16. Condensor
 The condenser or the cooler
consists of coils of pipe in which
the high pressure & temp. vapour
refrigerant is cooled & condensed.
 The refrigerant while passing
through the condenser, rejects its
latent heat to surrounding
condensing medium which is
normally air or water.
Thus hot refrigerant vapour
received from compressor is
converted into liquid form in
condenser.

17. Dryer or Receiver has two
main functions
 First is to filter refrigerant.
To eliminate moisture from
refrigerants

18. Receiver
The condensed liquid refrigerant
from the condenser is stored in a
vessel, known as receiver, from
where it is supplied to the
expansion valve or refrigerant
control valve.

19. Dryer or receiver working
 It filters refrigerant with the help
of Filters
 After filters refrigerant moves
toward Silica gel which absorbs
moisture from refrigerants and
send towards expansion device

20. Expansion Valve
 Its main function is to reduce the
pressure of Refrigerant
 For this . It use a small hole , when
refrigerant passes through this
hole pressure is reduced due to
restriction or resistance
 It sends low pressure low temp
refrigerant to Evaporator.

21. Expansion Valve

22. Evaporator
& its two main functions
 1st is to absorbs surroundings
heat.
 2nd is to change liquid refrigerant
into vapour refrigerant.

23. Evaporator
An evaporator consists of coils of pipes
in which the liquid vapour refrigerant at
low pressure & temp. is evaporated &
changed into vapour refrigerant at low
pressure & temp.
During evaporation process, the liquid
vapour refrigerant absorbs its latent
heat of vaporization from the medium
which is to be cooled.

24. Evaporator
 It absorbs surrounding heat and
starts boiling refrigerant
 It absorbs heat from things (which
is to be cooled) places inside of
refrigerants.

25. Application of Vapour
Compression Systems
 All refrigerants
single door Refrigerator , double
door refrigerator, window air
conditioner, split air conditioner ,
central air conditioner plant ,
water cooler , ice candy plant,
deepfreezes , cold storage plant

26. Advantages
• Smaller size for a given refrigerating
capacity
• Higher coeff. of performance
• Lower power requirements for a given
capacity
• Less complexity in both design &
operation
• It can be used over large of temp.

27. Domestic Refrigerator
• The application of refrigeration for
domestic purposes are mainly in the form
of domestic refrigerators & home freezers.
• The main purpose of this type of
refrigeration is to provide low temp. for
storage & distribution of foods & drinks.

28. Contd….
• It represents a significant portion of the
refrigeration industry due to the use of
these units in large number.
• For domestic preservation, the storage is
generally short term. The domestic
refrigerators used for the purposes are
usually small in sizes with rating in ranges
from 1/20 to ½ tonne.

29. Contd….
The requirement of domestic refrigerator is
that:-
• it should be simple in construction
• automatic in action
• nominal in initial cost

30. THANKS…..