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course outline

Safety and first aid in the workshop.
- Workshop rules and regulations
- Safety devices/equipment – helmet, goggles, safety boots, hand gloves, overall, apron sand bag, fire extinguishers, etc.
- Accident: causes and prevention techniques.
- First Aid - materials for First Aid, charts, posters and first aid box, etc.
- Application of first aid materials.
Energy, matter and power.
- Energy
- The process of energy conversion electrical to mechanical, gas to vapour, mechanical to heat.
- Meaning of internal energy.
- Enthalpy of a fluid substance, its pressure, volume and temperature of internal energy.
- Nature of matter.
- The ph diagram of refrigerant.
- State of matter – solid, liquid, gas or vapour.
- Change of state of matter.
- power.
- The meaning of power.
- Calculation of power used by a compressor.
- Unit of power: watts and kilowatts unit of heat: joules and kilojoules.
Temperature and pressure.
- Temperature and its measurement
- Concept of temperature.
- Different types of thermometer e.g. gas, resistance, liquid and thermocouple.
- Temperature scale conversion
- International practical temperature
- Pressure and its measurement
- Concept of pressure
- Different types of pressure measuring devices e.g. barometer, manometer, bourdon tube gauge.
- Pressure measurement
- Uses of suction and high pressure gauges.
- Effects of temperature, pressure and volume in refrigeration and air conditioning systems.
- Gas law, Boyles law, Charles law and Dalton's law.
- Calculations involving general gas law. Formulae:-
- Plotting various temperature scales
Refrigeration and air conditioning systems.
- Introduction to refrigeration.
- Refrigeration cycle – Evaporation, compression, condensation and expansion.
- Layout diagram of refrigeration systems.
- Types and applications of the various forms of refrigeration.
- Principles of operation of forms of refrigeration system.
- Functions of the component and accessories e.g. relay, solenoid valves, capacitors and thermostat.
- Refrigerants
- Definition and types of refrigerants
- Chemical names and formulae.
- Properties and uses of refrigerants.
- Refrigerants flow controls e.g. TEV, AEV, capillary tube.
- Operations of refrigerant flow controls.
- Air-Conditioning processes
- Psychometric properties of air.
- The processes of air conditioning: heating and cooling.
- Latent and sensible heat, saturated and super-saturated vapour.
Compressors, Condenses and Evaporators
- Compressors
- Types of compressors
- Construction of compressors.
- Working principles of compressors.
- Condensers.
- Construction of condensers.
- Calculation of heat load on condensers.
- Types and functions of liquid receiver and service valves.
- Principle of operation of liquid receiver and service valves.
- Types of evaporators.
- Construction and services of evaporators.
- Working principles of evaporators.
- Heat load estimates on evaporators.
Workshop practices.
- Basic tools used in refrigeration and air-conditioning workshops
- Basic tools – hacksaw, coil spring benders, reamers, tube cutters, etc.
- Fault diagnosis and trouble shooting.
- Tools and procedures for servicing window unit air-conditioner.
- Different methods of diagnosing faults systematic and observation.
- Common faults in refrigeration systems and their symptoms – leakage, faulty units, faulty compressor, poor cooling and current leakage.
- Maintenance and Testing
- Techniques of effective repairs in refrigeration and air-conditioning systems.
- Techniques of trouble shooting in a given system.
- Testing for leakages, polarity, insulation continuity, pressure and efficiency.
- Maintenance of compressors, evaporators, motors, condensers, valves, accumulators and contactors.
Installation processes
- Piping, Ducting and Trunking
- Concept of piping, ducting and trunking.
- Piping a condenser and an evaporator.
- Ducting, trunking and installation of air-conditioners.
- Piping, ducting and trunking tools – mallet hammer, flaring tools, silver tape, dot-punch, bending spring, amaflex, hacksaw, PVC pipes.
- Motors and generators
- Types, functions, operations and application of motors and generators.
- Installation procedures for motors and generators.
- Maintenance of motors and generators in a refrigeration system.
- Cold room
- Working principles of cold room.
- Cold room installation procedures.
- Factors affecting cold room operations.
Insulation processes
- Insulation of refrigeration and air-conditioning system.
- Importance of insulation of refrigeration and air-conditioning systems.
- Types of insulating materials – glasswool, fibre glass, polysterene foam, wood, bitumen, ceramic, etc.
- Functions and properties of insulation materials.
- Procedure for insulating refrigeration and air-conditioning systems.
Entrepreneurship.
- Business concept.
- Concept of business enterprise and types of businesses – sole proprietorship, partnership, limited liability, etc.
- Marketing
- Sources of finance – loan, mortgage, shares, overdrafts, savings, etc.
- Types, functions of marketing styles.
- Meaningful marketing at the least cost.
- Marketing protocol and cost.
- Accounting
- Principles of Accounting.
- The concept of business as a separate entity.
- Ledger, trial balance and balance sheet.

Welding

NECO SSCE

course outline