The document summarizes the main components of a refrigeration system: 1. The evaporator operates at low temperature and pressure, the condenser operates at high temperature and pressure, and the expansion device maintains a pressure differential. 2. The refrigeration cycle involves the compressor increasing pressure and the condenser removing heat outdoors before the evaporator cools air/water and the expansion valve reduces pressure. 3. Key components include the compressor, condenser, expansion valve, evaporator, filter drier, sight glass, pressure switch, solenoid valve, and thermostat/control system.

1. 1 |
Introduction- Condensing Unit Components

2. 2 |
Refrigeration System: realisation
• Evaporator ( 1 )
–low temperature
–low pressure
• Condenser ( 2 )
–high temperature
–high pressure
• Expansion device ( 3 )
–throttle
–keeps pressure differential
• Compressor ( 4 )
–pumps refrigerant
1
4
3
2
Q
.
Q
.
P

3. 3 |
The Simple Refrigeration System
Compressor
Condenser Evaporator
Expansion device
Low pressure sideHigh pressure side

4. 4 |
The Simple Refrigeration System
Compressor
Evaporator
Condenser
Expansion valve
Increment pressure
Remove heat outdoor
Cooling air / Water
Reduce pressure

5. 5 |
Refrigeration Cycle
Enthalpy
Compressor
Condenser
Receiver
Pressure
Evaporator

6. 6 |
The compressor
The task of the compressor is to increase the pressure of the
superheated vapour coming from the evaporator so that it can be
condensed via a normal available media such as air or water.
The discharge pressure ( condensing pressure ) is solely determined
through the medium ( water / air ) used in the condenser. The
condensing pressure is not determined by the compressor.
The capacity of the compressor is normally controlled by the suction
pressure. Capacity control can be performed via cut-in / cut-out of
cylinders or by controlling the speed of the electric motor.
On very small plants the compressor is normally controlled
synchronously with the thermostat, without capacity control.

7. 7 |
Compressor

8. 8 |
Semi Hermatic Compressor

9. 9 |
Hermatic Compressor

10. 10 |
Condenser

11. 11 |
Condenser
The condenser is a heat
exchanger in which the
heat from the evaporator
and the electric motor is
removed from the refrigeration
system.
In the condenser the heat from
the discharge gas is transferred
to the water, air or combination
of the two (evaporative).
Water-cooled
Air-cooled
Evaporative

12. 12 |
Water-cooled condensers
Modern type with special
copper tubes with very large
internal and external
surfaces

13. 13 |
Air-cooled condenser

14. 14 |
Ball Valve – Stop Valve
• The stop valve is used on discharge, liquid and suction line
• The function is to isolate part of system for service, diagnostic
and measuring

15. 15 |
Filter Drier
• Protect systems from moisture, acids, and solid particles

16. 16 |
The Function of a Filter Drier in a Refrigeration System
Remove other solid contaminants,
corroded materials and acid.
Protect the refrigeration system
by capturing harmful substances.
Minimizes chemical reactions in
the system by removing foreign
particles.
Molecular sieve prevents ice
formation in the expansion device.
Filter Driers – Operation

17. 17 |
Sight Glass
• The sight glass is used to indicate the condition of liquid in the
line
• The moisture content in the refrigerant

18. 18 |

19. 19 |

20. 20 |
The expansion valve
The task of the thermostatic expansion valve ( TEV ) is to supply
the evaporator with the correct amount of liquid during all load
conditions.
It ensures that the refrigerant is evaporated and that the vapour has
a certain amount of superheat when it leaves the evaporator.
This ensures that the evaporator is used to the optimum and that
no liquid comes back to the compressor.
The TEV valve is designed for one specific refrigerant.The TEV
valve is a P-controller, which means that superheat increases as
the degree of opening of the valve increases.
TEV

21. 21 |

22. 22 |
Evaporator
• Protect systems from moisture, acids, and solid particles

23. 23 |
The primary task of the evaporator is to cool the
dedium to the required temperature. An air-cooled
evaporator is, as the word indicates, surrounded by
air.
Normally this air is cooled by counterflow.
The purpose of the fins on the evaporator is to make
it more effective. The fin increase the heat transfer
surface of the evaporator significantly.
Heat is transferred mainly by conduction.
The difference between evaporator temperature and
air temperature is normally between 6 - 10 K. This
difference ( LMTD) is an expression for the load on
the evaporator.
To ensure that the evaporator is effective and has
capacity to cool the air, it is defrosted at certain
intervals.
Evaporator

24. 24 |
Ceiling-mounted evaporator
Natural air circulation
Ceiling-mounted evaporator
Forced air circulation
Evaporators
Fig. 20. The electronic expansion valve.
Set point
∆ts ∆t
ti = 0 °C
te = -4 °C
ts = 1 °K
Plate heat exchanger

25. 25 |
Evaporator cross-section

26. 26 |
Solenoid Valve
• To automatic shut down the system when the temperature
achieved

27. 27 |
Pressure Switch
• Protect system from high and low pressure

28. 28 |
Protective Function:
pressure limiting and cut out against
excessive pressures, against loss of
charge
Control Function:
compressor cycling, fan-cycling, pump-
down
Application
Pressure Switch

29. 29 |
Thermostat/Control
• Shut down the system when temperature achive