1. BASIC MECHANICAL ENGINEERING

2. REFRIGERATION AND AIR CONDITIONING

3. Vapour Compression Refrigeration System Vapour Compression Refrigeration System Basic Components Basic Components –Compressor –Condenser –Expansion Valve –Evaporator

4. Refrigerator

5. Processes 1. Low temp., Low pr., Vapour enters Compressor 1. Low temp., Low pr., Vapour enters Compressor 2. High temp., High Pr., Vapour enters Condenser 2. High temp., High Pr., Vapour enters Condenser 4. High pr. Saturated Liquid enters Expansion Valve (Throttle Valve) 4. High pr. Saturated Liquid enters Expansion Valve (Throttle Valve) 5. Low temp., wet Vapour enters Evaporator 5. Low temp., wet Vapour enters Evaporator

6. Vapour Compression Refrigeration System Vapour Compression Refrigeration System

7. Vapour Absorption Refrigeration System Vapour Absorption Refrigeration System Difference in method of converting the refrigerant vapour back into liquid. Difference in method of converting the refrigerant vapour back into liquid. Compressor replaced by combination of Absorber and Generator. Compressor replaced by combination of Absorber and Generator. Absorber and Generator. Absorber and Generator. Vapour from evaporator is dissolved in the cold water in the absorber which thus turns into a warm strong solution. Vapour from evaporator is dissolved in the cold water in the absorber which thus turns into a warm strong solution. The strong solution is heated in generator to separate refrigerant vapour. The strong solution is heated in generator to separate refrigerant vapour. Remaining weak solution is sent back to absorber to be used as solvent Remaining weak solution is sent back to absorber to be used as solvent

8. Vapour Absorption Refrigeration System Vapour Absorption Refrigeration System

9. Comparison – Advantages of Absorption System Heat is used as major source of energy Heat is used as major source of energy No moving parts No moving parts Performance is not affected by load on compression Performance is not affected by load on compression No danger of liquid traces in suction line No danger of liquid traces in suction line Works on low evaporator pressure Works on low evaporator pressure Automatic operation is easy Automatic operation is easyCOP Coefficient of Performance, COP = Heat extracted / Work by Compressor

10. Unit & Properties The rate of heat absorbed by the system from the body to be cooled, equivalent to the latent heat of fusion of 1 ton of ice from and at 0 0 C in 24 hours is called one ton of refrigeration. 1 ton of refrigeration = 3,5167kJ of heat removal / second Properties Condensing & evaporation pressures higher than atmospheric pr., critical temp high, low freezing temp., low sp.heat, high L.H., low sp.volume, low viscosity, high thermal conductivity, stability, inflammability….

11. Air Conditioning

12. Terminology Terminology –Dry air, Moist air –Specific humidity –Relative humidity –Dry bulb temperature –Wet bulb temperature –Dew point temperature –Sensible heat –Total heat

13. Physical Processes Air Purification Air Purification –Air filtration, Air sterilization, Air ionisation, Odour suppression Temperature Control Temperature Control –Indirect, Direct Humidity Control Humidity Control –Dehumidification, Humidification Air Distribution Air Distribution

16. Comfort Air conditioning Combination of Dry bulb temp., Relative humidity and Air velocity Combination of Dry bulb temp., Relative humidity and Air velocity Effective Temperature Effective Temperature It is the dbt of a sample of saturated air which will give a particular feeling of comfort to the same percentage of people as any other combination of dbt and RH.

17. Window Air conditioning

18. Winter Air conditioning

19. Summer Air conditioning

20. Viscous Filter

21. Wet Filter

22. Air Cooling - Indirect

23. Air Cooling - Direct

24. Dehumidifier

25. Atomisation Humidifier

26. Forced Evaporation Humidifier

27. Air Distribution