Refrigerator working explained clearly in this slide, and its principle

1. Lab @ Home
WORKING OF
REFRIGERATOR
SUBMITTED TO : MISS SEEMA
SUBMITTED BY :ANNU KUMAR
SECTION : 1708
ROLL NO : B41
REG NO : 11711796

2. TABLE OF CONTENT
BRIEF HISTORY
IMPORTANT TERMS
IMPORTANT PARTS and MATERIALS
CONSTRUCTION
PRINCIPLE OF REFRIGERATION
BASIC MALFUNCTIONING
SYMBOL MEANINGS ON FRIDGE

3. Brief History
01
• IN 1755 early attempt by W Cullins
• IN 1835 BY J Perkins
02
• General Electric Introduces The First Domestic
Fridge In 1911
• Followed By Frigidaire In 1915
03
• Followed By Kelvinator In 1918
• Advancement till date…………………..

5. IMPORTANT TERMS
 COOLING: a natural process, thermal equillibrium
 REFRIGERATION: forced cooling below ambient temperature

6. Some concepts
ABSENCE
ABSENCE
ABSENCE
• HEAT
• cooling
• LIGHT
• darkness
• AIR
• vacuum

7. The Basic Principle
Fig.1 Basic principle of refrigeration is illustrated in this figure
• You simply pass a colder liquid continuously
around the object that is to be cooled.
• This will take heat from the object.
• Due to the temperature difference, the object loses
heat to the refrigerant liquid.
• The refrigerant in turn is heated due to heat
absorption from the apple.

8. Important components

9. Throttling Device
 The throttling device obstructs the flow of liquid;
 Cold liquid is produced with the help of this device.
 The throttling device is a capillary tube.
 The capillary tube has an approximate length of 2 m and an inside
diameter of around 0.6 mm.
 Throttling at the inlet, the refrigerant should be a high-pressure
liquid. The throttling device restricts the flow, which causes a
tremendous pressure drop.
 Due to the drop in pressure, the boiling point of the refrigerant
is lowered, and it starts to evaporate. The heat required for
evaporation comes from the refrigerant itself, so it loses heat, and
its temperature drops.

10. Evaporator - Heat Absorption
Process
 Cold liquid refrigerant is
passed over the body that
has to be cooled.
 During the heat absorption
process, the refrigerant
further evaporates and
transforms into pure
vapor. A proper heat
exchanger is required to
carry the cold refrigerant
over the body. This heat
exchanger is known as an
evaporator.

12. Compressor
 The function of a compressor is to increase the
pressure, and corresponding saturation temperature
(boiling point) of the refrigerant vapor to high enough
level so the refrigerant can condense by rejecting its
heat through the condenser.
 Types
Hermetic motor, hermetic compressor
 A hermetic or sealed compressor is one in which both
compressor and motor are confined in a single outer welded
steel shell. The motor and compressor are directly coupled on the
same shaft, with the motor inside the refrigeration circuit.

14. Condenser
 This is fitted outside the refrigerator, and the refrigerant
temperature is higher than atmospheric temperature.
So heat will dissipate to the surroundings. The vapor
will be condensed to liquid, and the temperature will
return to a normal level

15. Have some view

17. OTHER COMPONENTS LIST
• Thermostat
• Relay capacitor
• Refrigerants
• Defrost system

18. Thermostat working principle
 A thermostat is a component which senses
the temperature of a system so that the system's
temperature is maintained near a desired set point.
 Thermostats are used in any device or system that
heats or cools to a set point temperature,
 Examples include building heating, central heating, air
conditioners, HVAC systems, water heater
 Ovens and refrigerators
 Medical equipment .

20. Overload Or Relay-Start
Capacitor
 The overload relay is a protection device used in the compressor circuit on
your refrigerator. Power is applied to the compressor motor windings
through the overload device, and the relay is used to add the start
winding in the circuit until the compressor is at running speed. If the
fans are running and your compressor won’t start or if you hear a clicking
sound from the unit, check the overload relay for signs of overheating.
arcing.

21. Refrigerant
 R-134a Refrigerant HFC-134a (1,1,1,2-
Tetrafluoroethane)
 Widely used in many air conditioning and
refrigeration systems globally.
 It is a hydro-fluorocarbon (HFC) that does not
contribute to ozone depletion; also the first non-
ozone-depleting fluorocarbon refrigerant to be
commercialized.

22. Defrosting
 Defrosting is
the melting of an object
or bringing a device's
temperature above
the freezing point to
remove ice.
 Over time, as the door is
opened and closed,
letting in new air, water
vapor from the air
condenses on the
cooling elements within
the cabinet.

26. THANK YOU !