Refrigeration System Components 1 Faculty Name: Prof. Ajaypalsinh G. Barad Branch: Mechanical Semester: 6 th Name of Subject: Refrigeration and Air Conditioning
Refrigeration System
Components
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Faculty Name: Prof. Ajaypalsinh G. BaradBranch: MechanicalSemester: 6th
Name of Subject: Refrigeration and Air Conditioning
Outline
• Introduction
• Compressor
• Condenser
• Expansion Device
• Evaporators
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Compressors:
• It removes low temperature and low pressure
refrigerant vapours from the cooling coil through the
suction line.
• It compresses these refrigerant vapours by increasing
the pressure and temperature resulting in an increase
of boiling point of the refrigerant,
• It discharges the refrigerant vapours of high
temperature and pressure to condenser through
discharge line.
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Compressors:
There are mainly three types of compressors in use:
Reciprocating compressor,
Rotary compressor,
Centrifugal compressor
• Reciprocating and rotary compressors are more commonlyused for small capacities but for lower evaporatortemperatures.
• Centrifugal compressors are essentially large dischargecapacity compressors. These are preferred for higherevaporator temperatures applications like, water chillersand air conditioners. They offer high efficiency but areexpensive.
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Reciprocating Compressor:
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Reciprocating Compressor:
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Rotary Compressor:
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Rotary Compressor:
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Rotary Compressor:
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Rotary Compressor:
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Rotary Compressor:
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Centrifugal Compressor:
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Screw Compressor:
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Scroll Compressor:
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Scroll Compressor:
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Hermitecally Sealed Compressor:
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Condensers:
• A condenser is a heat exchanger which removes heat
of the hot vapor refrigerant discharged from the
compressor.
• The condenser are classified into the following three
groups:
(1) Air-cooled condensers
(2) Water-cooled condensers, and
(3) Evaporative condensers.
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Air-cooled condensers
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Water-cooled condensers
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Water-cooled condensers
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Water-cooled condensers
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Evaporative condensers
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Expansion devices:
• Following are the main types of expansion devices
used in industrial and commercial refrigeration and air
conditioning system.
1.Capillary tube
2.Hand-operated expansion valve
3.Automatic or constant pressure expansion valve
4.Thermostatic expansion valve
5.Float valve
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Expansion devices:
• Capillary tube
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Expansion devices:
• Capillary tube
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Expansion devices:
• Capillary tube
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Expansion devices:
• Capillary tube
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Expansion devices:
Capillary tube
• The pressure drops due to the frictional resistance
• For a given state of the refrigerant, the pressure drop is directly
proportional to the length and inversely proportional to the bore
diameter of the tube
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Expansion devices:
• Hand operated expansion valve
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Expansion devices:
• Automatic Expansion Valve
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Expansion devices:
• Thermostatic Expansion Valve
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Evaporators:
• The function of an evaporator is to absorb heat from
the surrounding location or medium which is to be
cooled by means of a refrigerant.
• The evaporators may be classified as follows:
According to operating conditions:
(i) Flooded type evaporators;
(ii) Dry or direct expansion type evaporators.
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Evaporators:
According to type of construction:
• Bare tube coil evaporator,
• Finned tube evaporator,
• Plate evaporator,
• Shell and tube evaporator,
• Shell and coil evaporator,
• Tube-in-tube evaporator,
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Evaporators:
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Evaporators:
• Capillary tube
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Evaporators:
• Bare tube coil evaporator
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Evaporators:
• Finned tube evaporator
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Evaporators:
• Plate Evaporator
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Evaporators:
• Shell and tube evaporator
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Evaporators:
• Shell and Coil
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Evaporators:
• Tube in Tube
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Refrigeration piping:
Selection of piping and fittings on the basis of
• Frictional resistance offered by pipe wall to flow of fluid,
• Velocity of flow.,
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Refrigeration piping:The design and operation of refrigerant piping system are as
follows:
• Ensure proper feed of refrigerant to the evaporators.
• Refrigerant line be so designed that pressure drop is not
excessive.
• Excessive amounts of lubricating oil may not be trapped in
any part of the system.
• It should protect the compressor from the loss of refrigerant
and lubricating oil.
• It should prevent liquid refrigerant from entering the
compressor during operating and idle time.
• It should maintain dry and clean system.44
Refrigeration Accessories :
Oil separator:
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Refrigeration Accessories :
Sight glass:
The sight glass is used as for,
• Moisture indicator.
• Liquid indicator.
• Liquid level indicator.
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Refrigeration Accessories :
Driers :
• Moisture in refrigeration systems is factor in the formation
of acids, sludge and corrosion.
• Drier is used to remove moisture from the system.
• It is placed in liquid line just before a strainer.
• It has silica gel in it to absorb the moisture either left over
in the system after charging or developed over a period due
to chemical action on oil.
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Refrigeration Accessories :
Filters :
• The filters act to strain out any particles that may be in
the system.
• Any particles can plug capillary tubes and thermostatic
expansion valve screens.
• The filter is placed at the inlet to the expansion device.
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Refrigeration Accessories :
Receiver :
• A receiver is a storage area for refrigerant.
• The liquid from condenser goes by gravity to a receiver.
• It is used to take care of load variation.
• It also help the condenser to drain refrigerant freely.
• The outlet tube of the receiver ensures that only liquid
goes to expansion device.
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Refrigeration Controls :
The controls used to cycle the refrigerating system on or
off are of two principle type,
• Temperature actuated,
• Pressure actuated.
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Refrigeration Controls :
Temperature actuated control:
• A temperature actuated control is also known as
thermostats.
• The temperature actuated controls are:
– Bulb type temperature sensing element,
– Bimetal type temperature sensing element.
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Refrigeration Controls :
Pressure actuated controls:
• They are used to control the pressure of the refrigerant in
the system. It is used as safety controls.
• Low pressure cutout
• High pressure cutout
• Oil failure cutout
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Thermal insulation:
• The materials having extremely low thermal conductivities
are called insulating materials.
• Desired properties of an ideal insulating material
– Thermal conductivity
– Permanence
– Strength
– Water-repellent
– Fire-proof
– Light weight
– Odorless
– Low-cost
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Classification of insulating materials:
• Flake insulation
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Classification of insulating materials:
• Fibrous insulation
– Organic or inorganic and may or may not be bonded.
– Glass or Rockwool are the most common materials
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Classification of insulating materials:
• Granular insulation
– Composed of small nodules that contain voids
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Classification of insulating materials:
• Cellular insulation
– Composed of small individual cells produced from glass,
rubber or plastic
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Classification of insulating materials:
• Reflective insulation
– Composed of parallel thin sheets of foil having high thermal
reflectance
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