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Air conditioning

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Air conditioning

  1. 1. AIR CONDITIONING<br />BCD<br />UNIT-V<br />Prof S S JAHAGIRDAR<br />BE (CIVIL), ME(ENV.),PhD(persuing)<br />NK Orchid college of Engg. and Tech. , Solapur<br />
  2. 2. Definition<br />Process of treating the air so as to control simultaneously its temperature, humidity, purity and distribution to meet the requirements of controlled space.<br />
  3. 3. Requirements of a conditioned space<br />Comfort and health of occupants<br />Needs of certain industrial processes<br />Efficient working of commercial premises/offices<br />
  4. 4. Functional classification<br />Comfort air conditioning : - Aim at giving max human comfort to occupants/users of conditioned space<br />Industrial air conditioning : - The coditioning creates, controls and maintains such an environment inside the conditioned space, that it would suit best to the needs of industry.<br />
  5. 5. Classification based on season/Temperature<br />1) Summer air conditioning <br />In summer outside temp is more and hence cooling of air is required<br />Consists of <br />Air cleaning<br />Air cooling<br />Dehumidification<br />Air distribution/circulation<br />
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  7. 7. 2) Winter air conditioning<br />In winter outside temperature is low hence heating of air is needed for comfort.<br />Cycle of operations consists of <br />Air cleaning<br />Air heating<br />Humidification<br />Air distribution/circulation<br />
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  9. 9. Essentials of air conditioning system<br />Temperature control <br />Effective temp = 200C to 230C in summer<br />Effective Temp = 180C to 220C in winter<br />For Indian conditions 250C with 60% relative humidity to 300C with 45 % relative humidity, with air velocity not exceeding 10 m/min<br />
  10. 10. 2) Humidity control<br />During summer dehumidification is done so that relative humidity is 40 to 50%<br />During winter humidification is done so that relative humidity is 50 to 60 %<br />
  11. 11. 3) Air Velocity control<br />High velocity of conditioned air may cause greater temperature difference between outside and inside.<br />Velocity = 6 to 9 m/sec is desirable<br />
  12. 12. 4) Air Quality control<br />Air should be free from odour, toxic gases, bacteria and other micro-organisms<br />
  13. 13. Essentials of air conditioning system<br />Filtration<br />Heating (in winter)<br />Cooling (in summer)<br />Humidification<br />Dehumidification<br />Air circulation or distribution<br />
  14. 14. 1) filtration<br />Should be capable of removing dust, ash, smoke, bacteria etc<br />Should be capable of holding moderate amount of dust without affecting the efficiency<br />Should offer low resistance to flow of air<br />Workable under sufficient range of velocities.<br />Should afford easy cleaning manually or mechanically<br />
  15. 15. 2) Heating<br />Heating is necessary in winter so as to compensate heat loss from room.<br />Pre heating of incoming air may be done by passing over air furnaces or coils through which hot water is circulated.<br />
  16. 16. 3) Cooling<br />Cooling of incoming air is necessary in summer.<br />Principle of mechanical refrigeration is used.<br />
  17. 17. 4) Humidification<br />Humidification or addition of water is necessary in winter when air because of low temp has less humidity.<br />Incoming air is passed through pans of water or wet cloth strips<br />
  18. 18. 5) Dehumidification<br />In this process certain amount of water is extracted from air.<br />This is done in summer where incoming air is cooled.<br />Adsorbents can be used to adsorb excess moisture from air<br />
  19. 19. 6) Air circulation or distribution<br />
  20. 20. END<br />

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