AIR-CONDITIONING & REFRIGERATION TECHNOLOGY CLASS XII
1 2 3 4 5
S.No. Subject Periods/ Week Examination Total
Theory Prac. Total Theory Prac. Marks
Marks: Hrs. Marks: Hrs.
1. Language I 7 - 7 100 3 - - 100
2. Language II or 7 - 7 100 3 - - 100
Mathematics (041)
As per Academic Stream
3. General Foundation 4 1 5 80 3 20 3 100
Course
4. Vocational Elective Papers
I. Engg. Science 1 7 8 70 3 30 3 100
a. Engg. Drawing (0) (4) - (40) - - - -
b. Workshop (1) (3) - (30) - - - -
Technology
II. Air Conditioning & 3 5 8 40 3 60 3 100
Refrigeration III
III. Air Conditioning & 3 5 8 40 3 60 3 100
Refrigeration IV
5. Physical & Health 2
Education.
Additional (optional) Papers
I. Applied Physics 3 2 5 60 3 40 3 100
II. Civil Engg. 3 2 5 60 3 40 3 100
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GENERAL FOUNDATION COURSE Class XII
(Part I & II same as given in Electrical Technology on Page No. 25)
ELECTIVE II
ENGINEERING SCIENCE Class XII
(Same as given in Electrical Technology on Page No. 28)
ELECTIVE II
AIR CONDITIONING & REFRIGERATION III
3 Hours Class XII Marks: 40
Theory
1. Psychrometric Processes - Sensible Cooling and Sensible Heating, Cooling with
dehumidification, cooling with adiabatic humidification, chemical dehumidification,
heating and humidification. Mixing of air streams. Absorption. Dehumidifiers. Steam
Injection, Coil and Spray Equipment. Evaporative cooling, Air Washers. Bypass
Factor. 5
2. Principles of Load Estimating, Internal and External System Heat Gains, ventilation, air
cleaning. Room sensible heat factor, effective room sensible heat factor. 5
3. Refrigerant controls. Types of expansion devices and sensible heat factor, construction
and operation of automatic and thermostatic valves, capillary tubes, low and high
pressure side float valves, testing and adjusting thermostatic expansion valves, solenoid
valves.
6
4. Principles of heat transfer. Conduction, convection and radiation. Overall heat transfer
coefficient. Use of fans. Effect of air velocity on heat transfer coefficient. Properties of
insulating materials. 4
5. Evaporators. Types of evaporators - dry and flooded. Heat absorbed in evaporators.
Water chillers, brine coolers. Methods of defrosting. 4
6. Condensers. Air and water cooled, and evaporative types. Heat rejected in condensers.
Purging. Construction of condensers. Driers. Receivers. 4
7. Refrigerants, their properties and nomenclature. R 11, R 12, R 22, R 502, R 113, R 114,
ammonia, and carbon dioxide, pressure with various refrigerants indifferent systems; oil
miscibility; solubility in water. Secondary refrigerants. Brines and Glycols. 4
8. Absorption refrigeration system. 3
9. Applications. Ice manufacture, Cold storage. Ice Cream manufacture. Dairy
refrigeration etc. 2
10. Leak detection. Pressure Testing and Charging. 3
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PRACTICAL
AIR CONDITIONING & REFRIGERATION III 3 hrs. Class XII Marks: 60
1. Measurment of Air Flow with a Pitot Tube.
2. Study of flow control Devices.
3. Testing of Thermostats.
4. Experiment with Mixing of Air.
5. Experiment with Simple Heating.
6. Experiment with Steam Injection.
7. Experiment on. an Evaporative Cooler.
8. Energy Balance of an Air Conditioner.
9. Fault Detection.
10. Experiment on a Cooling Tower.
11. Study of expansion-valves; testing and adjusting.
12. Performance testing of Refrigerating system.
13. Volumetric Efficiency of a Reciprecting compressor, and Testing a compressor.
14. Pressure Testing and leak detection Methods.
15. Charging procedure and charging correctly a refrigerator.
List of Experiments 1. To dismantle a Reciprocating compressor open and sealed typed.
2. To assemble a Reciprocating compressor open and sealed type.
3. To cut gaskets.
4. To Flare, Swedge, bend, punch and braze copper tubes.
5. To charge and test oil in the compressor.
6. To repair and service condenser and evaporator.
7. To study different types of flow control devices and to test a refrigerant control valve.
8. To test the leakage of the system.
9. To evacuate the system.
10 To prepare series and parallel circuits and testing board.
11. To change the refrigerant in the system.
12. To identify fault/faults in refrigeration system.
13. To solder, rivet and scam a thin sheet.
Note: Each student should perform all the experiments during the session.
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MARKING SCHEME Note: 1. Marks for sessional work will be awarded by the teacher concerned.
2. Students may be asked to perform any one experiments.
Distribution of Marks
1. Experiment: 40
i) Identification of components 8
ii) Identification of different 8
parts of compressor
iii) Functioning of different components 8
iv) Working of components 8
v) Methods of working and safety 8
precautions observed
2. Viva Voce: 10
i) Questions related to the experiment assigned 3
ii) Questions related to the 4
remaining experiments
iii) Questions based on related 3
concepts
3. Sessional Work 10
i) All listed experiments performed 5
ii) Maintenance of proper record 5
GUIDELINES FOR EXAMINERS
(Common for Elective II & III)
Note: Examiner will evaluate the Candidates on the following guidelines:--
1. Systematic approach to the problem.
2. Safety Precautions and Sequence of work.
3. Initiative taken and concentration by the individual.
4. Proper use of tools.
5. Workmanship, finish and working ability must be given a special consideration.
6. Special attention to the tools and equipments taken by the individual.
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GENERAL INSTRUCTIONS TO THE CANDIDATES
(Common for both Elective II & III) 1. Proper dress must be-used by the student during practical and must be aware of the safety precautions to be observed.
2. Student must complete the practical himself and not merely watch others doing it.
3. Student should draw simple line diagram of the assembly components, circuits and note the important points.
4. Student must know the tools and equipments used for the particular exercise with the specification of each tool.
5. After completing the practical exercise student must write in his/ her practical note book. about the practical under the following headings:-
a) Title of Exercise.
b) Tools, equipment and material used with complete specifications.
c) Time taken for the particular exercise.
d) Procedure.
e) Safety precautions observed.
6. In case of any difficulty student must approach the teacher without any hesitation.
7. During practical work one should not disturb others.
8. Students must know how to repair the tools used in the exercise.
9. After using the tools should be cleaned and placed in a proper way.
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ELECTIVE III
AIR CONDITIONING AND REFRIGERATION IV
3 Hours Class XII Marks: 40
Theory
1. Air Conditioning Systems and Equipments. Classification of air conditioning systems-
all air and all water types. Fans, blowers, grills, resistors, filters, compressors, cooling
coils, condensers, air handling units, fan coil units. Heating and humidifying equipments.
Unit air conditioners, package units, central air conditioning plants. 10
2. Air Distribution. Systems of air distribution. Duct systems. Cooling Load. Air
quantities. Pressure in ducts-static pressure, velocity pressure Ad total pressure.
Friction Losses. Duct sizing. Duct lay-out and drawing. Duct construction. 10
3. Controls. Sensing elements-bimetallic, bulb and bellow, solenoids electric resistance
type etc. Actuating elements-thermostats, humidistats, pressurestats etc. 4
4. Modulating Motors. Construction and operation. Bypass controls. Use of chokes, for
controlling fan motor speeds. 4
5. Starters. Capacitors, relays, overload controls, for motors, and their servicing. 4
6. Refrigeration Controls. H. P. and L. P. cutouts, oil failure safety switches power element
testing. 4
7. Maintenance-Preventive and breakdown maintenance. Diagnosis and rectification of
faults in electrical system, refrigeration system and air conditioning system. Pressure
testing. Charging. Performance Testing.
PRACTICAL
AIR CONDITIONING AND REFRIGERATION IV 3 Hours Marks: 60
1. Study of Sensing Elements.
2. Study of Low and High Pressure Cut Outs.
3. Study of Thermostat, Humidstat, Pressure Stat, etc.
4. Study of capacitors, Relays, Overloads, chokes, etc.
5. Study of Modulating Motors.
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6. Study of pressure Drop in Ducts.
7. Testing of Power Elements.
8. Testing of Thermostats.
9. Repairing a Hermeticaly sealed Unit.
10. Complete Servicing of a Refrigerator.
11. Complete servicing of an Air Conditioner.
12. Fault Detection.
13. Adjusting the Automatic System.
14. Wiring Diagrams of an Air Conditioner and central plants.
15. Wiring Diagrams of Multicylinder Compressor for capacity control.
16. Industrial Visits.
LIST OF EXPERIMENTS 1. To test safety and operating controls such as Relay, Thermostat, L-P cut-out, H. P. cut- out, Over-load protector, solenoid valve, oil pressure, Failure Control, etc.
2. To carry out electric wiring of Refrigerator and Bottle Cooler.
3. To carry out electric wiring of window type Air Conditioner.
4. To test compressor for efficiency & earthing etc.
5. To service a window type Air Conditioner.
6. To find fault in Refrigerator and Bottle cooler.
7. To find fault in Air Conditioner.
8. To Check Comfort Conditions such as air, temperature, humidity, Air Motion etc.
9. To adjust the Automatic System.
10. To study compressor capacity control methods.
Note: Each student should perform all the experiments during the session.
MARKING SCHEME Marks: 60
Note: 1. Marks for sessional work will be awarded by the teacher concerned.
2. Students may be asked to perform any one experiments.
DISTRIBUTION OF MARKS
1. Experiment 40
i) Different components used in Refrigeration and
Air Conditioning 8
ii) Properties of air related to Air Conditioning 8
iii) Refrigerant controls 8
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iv) Electric wiring of window type Air Conditioner and
Refrigerator
8
v) Properties of Air related to A.C. 8
7. Viva-Voce: 10
i) Questions related to the experiments assigned 3
ii) Questions related to the remaining experiments 4
iii) Questions based on related concepts 3
3. Sessional Work: 10
i) All listed experiments performed 5
ii) Maintenance of proper record 5
Guidelines for examiners
General Instructions to the Students/candidates as per Elective II Page No. 117
ADDITIONAL SUBJECTS (OPTIONAL)