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P f S S JAHAGIRDARProf S S JAHAGIRDARBE (CIVIL), ME(ENV.),PhD(persuing)NK Orchid college of Engg and Tech SolapurNK Orchid college of Engg. and Tech. , Solapur

Process of treating the air so as toProcess of treating the air so as tocontrol simultaneously itstemperature, humidity, purityand distribution to meet theand distribution to meet therequirements of controlled space.

1) Comfort and health of 1) Comfort and health of occupantsp

2) Needs of certain industrial processes

3) Efficient working of 3) Efficient working of commercial premises/officesp /

Comfort air conditioning : - Aim atComfort air conditioning : - Aim atgiving max human comfort tooccupants/users of conditionedspacespaceIndustrial air conditioning : - Thecoditioning creates, controls andmaintains such an environmentmaintains such an environmentinside the conditioned space, that it

ld it b t t th d fwould suit best to the needs ofindustry.

1) Summer air conditioning ) gIn summer outside temp is more and hence cooling of air is requiredhence cooling of air is requiredConsists of

i) Air cleaning) Air coolingii) Air cooling

iii) Dehumidificationiv) Air distribution/circulation

2) Winter air conditioning2) Winter air conditioningIn winter outside temperature is low h h i f i i d d f hence heating of air is needed for comfort.Cycle of operations consists of

) Air cleaningi) Air cleaningii) Air heatinggiii) Humidification

Ai di t ib ti / i l tiiv) Air distribution/circulation

1) Temperature control Effective temp = 200C to 230C in summersummerEffective Temp = 180C to 220C in winterFor Indian conditions 250C with 60% For Indian conditions 25 C with 60% relative humidity to 300C with 45 %

l ti h idit ith i l it t relative humidity, with air velocity not exceeding 10 m/min

During summer dehumidificationDuring summer dehumidificationis done so that relative humidityyis 40 to 50%

h d fDuring winter humidification isdone so that relative humidity isdone so that relative humidity is50 to 60 %

High velocity of conditionedHigh velocity of conditionedair may cause greatery gtemperature differencebetween outside and insidebetween outside and inside.Velocity = 6 to 9 m/sec isVelocity 6 to 9 m/sec isdesirable

Air should be free fromAir should be free fromodour, toxic gases, bacteriaodour, toxic gases, bacteriaand other micro-organisms

1. Filtration2. Heating (in winter)3. Cooling (in summer)4. Humidification

Dehumidification5. Dehumidification6 Air circulation or distribution6. Air circulation or distribution

Should be capable of removing dust, ash, smoke bacteria etcsmoke, bacteria etcShould be capable of holding moderate

f d h ff hamount of dust without affecting the efficiencyShould offer low resistance to flow of airWorkable under sufficient range of Workable under sufficient range of velocities.Sh ld ff d l i ll Should afford easy cleaning manually or mechanically

Heating is necessary in winter soHeating is necessary in winter soas to compensate heat loss fromroom.Pre heating of incoming air may bePre heating of incoming air may bedone by passing over air furnacesor coils through which hot water iscirculated.circulated.

Cooling of incoming air isCooling of incoming air isnecessary in summer.yPrinciple of mechanical

f drefrigeration is used.

Humidification or addition ofHumidification or addition ofwater is necessary in winterwhen air because of low temphas less humidity.has less humidity.Incoming air is passed throughpans of water or wet cloth strips

In this process certain amount ofIn this process certain amount ofwater is extracted from air.This is done in summer whereincoming air is cooledincoming air is cooled.Adsorbents can be used toadsorb excess moisture from air