Skill Subject: Air Conditioning and Refrigeration

After successfully completing these two years of Senior Secondary skill course, the student would have acquired relevant appropriate and adequate technical knowledge together with the professional skills and competencies in the field of Air conditioning and Refrigeration Technology so that they will be able to properly equipped to take up gainful employment in this sector.

Total Marks: 100 (Theory - 60 and Practical - 40)

Part B: Skill

• Unit 1: Psychrometry
• Unit 2: Heat transfer and Air Distribution
• Unit 3: Components of Refrigeration Systems
• Unit 4: Electric controls
• Unit 5 : Commercial Applications
• Unit 6: Air-Conditioning Systems & Maintenance

Unit 1: Psychrometry

Psychrometric Processes - Sensible Cooling, Sensible Heating, Cooling with de-humidification, Cooling with adiabatic Humidification, Chemicaldehumidification, heating and humidification, Mixing of air- streams, Air Washers.

Unit 2: Heat transfer and Air Distribution

1. Principles of heat transfer, Conduction, Convection and Radiation. Properties of insulating materials.

2. Air Distribution, Systems of air distribution, Duct systems, cooling load and air quantities pressure in ducts, duct layout & construction.

Unit 3: Components of Refrigeration Systems

1. Condensers, Air cooled and water cooled, Evaporative Condensers, Heat Rejected in condensers, construction of condensers, Driers, receivers, Purging, Cleaning of Condensers.

2. Refrigerant Controls, Types of expansion devices and sensible heat factor, construction and operation of Automatic expansion valve, thermostatic expansion valve, and capillary tube, low side float valve, High Side float valve. Solenoid valves, testing and adjusting thermostatic expansion valves.

3. Evaporators, types of evaporators- Dry and flooded, Heat absorbed in evaporators, water chillers, brine coolers, Methods of defrosting.

4. Refrigerants, their properties and nomenclature - R11, R12, R22, R502, R113, R114, R134A, ammonia, and carbon dioxide.

Unit 4: Electric controls

1. Refrigeration Controls, H.P and L.P cutouts, Oil Pressure failure safety switch.

2. Motor Starters, capacitors, Relays, over load protectors and servicing of motors.

Unit 5 : Commercial Applications

Ice-Manufacture, cold-storage, Ice-Cream manufacture, Dairy refrigeration etc.

Unit 6: Air-Conditioning Systems & Maintenance

1. Air-Conditioning systems and equipments, classification of air-conditioning systems-all air systems, all water system types, Fans, Blowers, grills, resistors, filters, compressors, cooling coils, condensers Air-Handling Units, Fan coil Units, Central Air Conditioning plants. Ventilation Systems.

2. Leak Detection, Pressure testing and charging.

Practicals

1. Testing of Thermostats.

2. Experiment on an Evaporative Cooler.

3. Experiment on a Cooling Tower.

4. Study of expansion-valves, testing and adjusting.

5. Pressure testing and leak detection methods.

6. Charging Procedure and charging correctly a refrigerator.

7. Study of low and high Pressure cut-outs.

8. Study of Capacitors, Relays, Overloads, Chokes, etc.

9. Testing of Thermostats.

10. Repairing a Hermetically Sealed Unit.

11. Complete servicing of a Refrigerator.

12. Complete Servicing of an air-Conditioner.

13. Wiring diagrams of an Air-Conditioner and central Plants.

14. Wiring diagrams of Multicylinder Compressor for capacity control.

15. Industrial Visits.