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DESCRIPTION
Refrigeration and Air conditioningTRANSCRIPT
ELEMENTS OF MECHANICAL ENGINEERINGELEMENTS OF MECHANICAL ENGINEERING
Refrigeration &
Air – Conditioning
LOCATION & ATMOSPHERE OF GUJARATLOCATION & ATMOSPHERE OF GUJARAT
HIGHEST TEMPERATURE IN SUMMER 46 CHIGHEST TEMPERATURE IN SUMMER 46 C
AVERAGE TEMPERATURE IN MONSOON 26 C TO 32 C AVERAGE TEMPERATURE IN MONSOON 26 C TO 32 C
REQUIRED LOWERED TEMPERATURE FOR REQUIRED LOWERED TEMPERATURE FOR FOLLOWING PURPOSEFOLLOWING PURPOSE
FOOD PRESERVATIONFOOD PRESERVATIONLIKE DAIRY PRODUCT, VEGETABLES, FRUITS, MEATS, LIKE DAIRY PRODUCT, VEGETABLES, FRUITS, MEATS, FISH, ICE CREAM PRODUCTS ETC. FISH, ICE CREAM PRODUCTS ETC.
REQUIRED LOWERED TEMPERATURE FOR REQUIRED LOWERED TEMPERATURE FOR FOLLOWING PURPOSEFOLLOWING PURPOSE
TRANSPORTATION OF FOOD STUFFTRANSPORTATION OF FOOD STUFFLIKE DAIRY PRODUCT, VEGETABLES, FRUITS, MEATS, LIKE DAIRY PRODUCT, VEGETABLES, FRUITS, MEATS, FISH, ICE CREAM PRODUCTS ETC. FISH, ICE CREAM PRODUCTS ETC.
REQUIRED LOWERED TEMPERATURE FOR REQUIRED LOWERED TEMPERATURE FOR FOLLOWING PURPOSEFOLLOWING PURPOSE
COOLING OF WATERCOOLING OF WATER
REQUIRED LOWERED TEMPERATURE FOR REQUIRED LOWERED TEMPERATURE FOR FOLLOWING PURPOSEFOLLOWING PURPOSE
FOR MAKING ICEFOR MAKING ICE
REFRIGERATIONREFRIGERATION
THE METHOD OF REDUCING THE TEMP. OF A SYSTEM BELOW THE SURROUNDING TEMP.AND MAINTAIN IT AT THE LOWER TEMP. BY CONTINUOUSLY ABSTRACTING THE HEAT FROM IT.
PRINCIPLE OF REFRIGERATIONPRINCIPLE OF REFRIGERATION
Heat Rejected Work Input
Heat abstracted
High Temperature Reservoir
Low Temperature Reservoir
R
TYPES OF REFRIGERATIONTYPES OF REFRIGERATION
NATURAL REFRIGERATION NATURAL REFRIGERATION THE COOLING EFFECT IS
PRODUCED BY EVAPORATION OF LIQUID OR MELTING OF SOLIDS
MECHANICAL REFRIGERATION MECHANICAL REFRIGERATION THE COOLING EFFECT IS
PRODUCED BY EXTERNAL SOURCE OF MECHANICAL ENERGY OR HEAT ENERGY.
IT HAS THREE TYPESIT HAS THREE TYPES
VAPOUR COMPRESSION VAPOUR COMPRESSION CYCLECYCLE
VAPOUR ABSORPTION VAPOUR ABSORPTION CYCLECYCLE
AIR REFRIGERATION CYCLEAIR REFRIGERATION CYCLE
VAPOUR COMPRESSION REFRIGERATIONVAPOUR COMPRESSION REFRIGERATION
Condenser
Evaporator
High Pressure Side
Low Pressure Side
CompressorExpansion Device
12
3
4
REFRIGERANTREFRIGERANT
PROPERTIES:-PROPERTIES:-
IT IS A HEAT CARRYING MEDIUM WHICH ABSORBS HEAT FROM SPACE WHICH IS TO BE COOLED AND REJECT IT TO THE ATMOSPHERE. e.g. NH3, R-11, R-12, R-22, R-134a, CO2, AIR etc.
HIGH LATENT HEAT OF EVAPORATION.
GOOD THERMAL CONDUCTIVITY.
NON-TOXIC, NON FLAMMABLE.
IT SHOULD BE ECONOMICAL.
VAPOUR COMPRESSION REFRIGERATIONVAPOUR COMPRESSION REFRIGERATION
Condenser
Evaporator
High Pressure Side
Low Pressure Side
CompressorExpansion Device
12
3
4
Low pressure liquid refrigerant in evaporator absorbs heat and changes to vapour
VAPOUR COMPRESSION REFRIGERATIONVAPOUR COMPRESSION REFRIGERATION
The superheated vapour enters the compressor where its pressure is raised
Condenser
Evaporator
High Pressure Side
Low Pressure Side
CompressorExpansion Device
12
3
4
VAPOUR COMPRESSION REFRIGERATIONVAPOUR COMPRESSION REFRIGERATION
Condenser
Evaporator
High Pressure Side
Low Pressure Side
CompressorExpansion Device
12
3
4
The high pressure superheated gas is cooled in several stages in the condenser
VAPOUR COMPRESSION REFRIGERATIONVAPOUR COMPRESSION REFRIGERATION
Condenser
Evaporator
High Pressure Side
Low Pressure Side
CompressorExpansion Device
12
3
4
Liquid passes through expansion device, which reduces its pressure and controls the flow into the evaporator
DOMESTIC REFRIGERATORDOMESTIC REFRIGERATOR
IT WORKS ON VAPOUR COMPRESSION CYCLE.IT WORKS ON VAPOUR COMPRESSION CYCLE.
FRONT SIDE FRONT SIDE
BACK SIDE BACK SIDE
P-h & T-s DIAGRAM OF VCR SYSTEMP-h & T-s DIAGRAM OF VCR SYSTEM
P
h
T
S
CONDENSATION
CO
MPR
ESSIO
NEVAPORATION
EX
PA
NS
ION
1
23
41
2
3
4
h2h1h2=h3
P2=p3
P1=p4
s3 s4 s1=s2
T2
T3
T1=T4
Pressure-Enthalpy (p-h) Diagram
Temperature- Entropy (T-s) diagram
UNIT OF REFRIGERATIONUNIT OF REFRIGERATION
TON OF REFRIGERATIONTON OF REFRIGERATION
IT IS DEFINED AS THE AMOUNT OF HEAT REQUIRED TO REMOVED IN IT IS DEFINED AS THE AMOUNT OF HEAT REQUIRED TO REMOVED IN ORDER TO FORM ONE TON OF ICE IN 24 HOUS FROM WATER AT ORDER TO FORM ONE TON OF ICE IN 24 HOUS FROM WATER AT TEMPERATURE 0TEMPERATURE 0°C.°C.
LATENT HEAT OF ICE IS 335 KJ/KGLATENT HEAT OF ICE IS 335 KJ/KGREFRIGERATION REQUIRED TO PRODUCE 1 TON (1000 KG) ICE IN 24 REFRIGERATION REQUIRED TO PRODUCE 1 TON (1000 KG) ICE IN 24 HRS.HRS.
= 335X900 KJ/HR= 335X900 KJ/HR 24 24
=210 KJ/MIN=210 KJ/MIN
=3.5 KW=3.5 KW
1 TON OF REFRIGERATION 1 TON OF REFRIGERATION =3.5 KW=3.5 KW
ASSESMENT OF REFRIGERATIONASSESMENT OF REFRIGERATION
CO-EFFICIENT OF PERFORMANCECO-EFFICIENT OF PERFORMANCE
COP = REFRIGERATING EFFECT IN KWCOP = REFRIGERATING EFFECT IN KW
WORK OF COMPRESSOR IN KW WORK OF COMPRESSOR IN KW
VAPOUR ABSORPTION REFRIGERATIONVAPOUR ABSORPTION REFRIGERATION
Condenser Generator
Evaporator
AbsorberCold Side
Hot Side
Low pressure, low temp vapour NH3 coming from Evaporator enters in absorber where it is absorbed by weak solution coming from generator.
VAPOUR ABSORPTION REFRIGERATIONVAPOUR ABSORPTION REFRIGERATION
Condenser Generator
Evaporator
AbsorberCold Side
Hot Side
VAPOUR ABSORPTION REFRIGERATIONVAPOUR ABSORPTION REFRIGERATION
Condenser Generator
Evaporator
AbsorberCold Side
Hot Side
Strong solution enters into generator, where it is heated and NH3 seperated from solution.
VAPOUR ABSORPTION REFRIGERATIONVAPOUR ABSORPTION REFRIGERATION
Condenser Generator
Evaporator
AbsorberCold Side
Hot Side
NH3 vapour coming from generator rejects the heat in condensor and transform into liquid state.
VAPOUR ABSORPTION REFRIGERATIONVAPOUR ABSORPTION REFRIGERATION
Condenser Generator
Evaporator
AbsorberCold Side
Hot Side
Liquid NH3 is throttled through expansion device and it enters into evaporator
VAPOUR ABSORPTION REFRIGERATIONVAPOUR ABSORPTION REFRIGERATION
Condenser Generator
Evaporator
AbsorberCold Side
Hot Side
NH3 evaporates by absorbing latent heat of evaporation to produce refrigerating effect.
AIR REFRIGERATIONAIR REFRIGERATION
AIR REFRIGERATION IS WIDELY USED IN AIR REFRIGERATION IS WIDELY USED IN AEROPLANESAEROPLANES
WHY REFRIGERATION IS REQUIRED IN AEROPLANES?WHY REFRIGERATION IS REQUIRED IN AEROPLANES?
AIR RAMMINGAIR RAMMING
SOLAR RADIATIONSOLAR RADIATION
CONTROLSCONTROLS
PASSENGERSPASSENGERS
AIR REFRIGERATION SYSTEMAIR REFRIGERATION SYSTEM
COMPRESSOR
RAM AIR IN
BYPASS RAM AIR
HE
FAN
EXPANDER
AIR TO CABIN
AIR EXIT
ADVANTAGES OF ADVANTAGES OF AIR REFRIGERATIONAIR REFRIGERATION
1. AIR IS CHEAP & EASILY AVAILABLE REFRIGERANT.
2. AIR IS NON TOXIC & NON FLAMMABLE.
3. COLD AIR CAN BE DIRECTLY SUPPLIED TO THE REFRIGERATED SPACE SO THERE IS NO NEED OF EVAPORATOR WHICH RESULTS IN LESS WEIGHT OF THE SYSTEM.
WHAT IS AIR CONDITIONING?WHAT IS AIR CONDITIONING?
The Air conditioning is defined as the The Air conditioning is defined as the simultaneous control of :- simultaneous control of :-
TemperatureTemperature HumidityHumidity Air movementAir movement Air cleanlinessAir cleanliness
Air Conditioning Air Conditioning
APPLICATIONS OF APPLICATIONS OF AIR CONDITIONING AIR CONDITIONING
FOR HUMAN COMFORTFOR HUMAN COMFORT
To provide cooling or heating and conditioning of air as per To provide cooling or heating and conditioning of air as per comfort of human being. This is known as comfort air comfort of human being. This is known as comfort air conditioning.conditioning.
Comfort air conditioning means conditioning of air in such Comfort air conditioning means conditioning of air in such a way that the human being can feel good.a way that the human being can feel good.The standards for comfort conditions are:The standards for comfort conditions are:
Temp. - 17Temp. - 17°C to °C to 2525°C°CHumidity - 30% to 70%Humidity - 30% to 70%Velocity of air – 0.1 m/s to 0.25 m/sVelocity of air – 0.1 m/s to 0.25 m/s
APPLICATIONS OF APPLICATIONS OF AIR CONDITIONING AIR CONDITIONING
FOR HUMAN COMFORTFOR HUMAN COMFORT
APPLICATIONS OF APPLICATIONS OF AIR CONDITIONING AIR CONDITIONING
FOR HUMAN COMFORTFOR HUMAN COMFORT
APPLICATIONS OF APPLICATIONS OF AIR CONDITIONING AIR CONDITIONING
FOR COMMERCIAL USEFOR COMMERCIAL USE
To provide cooling or heating and conditioning of air To provide cooling or heating and conditioning of air as per required in some engineering manufacturing as per required in some engineering manufacturing processing. This is known as industrial air conditioning.processing. This is known as industrial air conditioning.