Presentation on theme: "AIRCONDITIONING BASICS"— Presentation transcript:
1AIRCONDITIONING BASICS AIR-CONDITIONING CAPACITYTR or ton of refrigeration - unit of measure of all air conditioners.Indicates a certain quantity of heat.British thermal unit (BTU) is the quantity of heat needed to raise the temperature of 1 pound of water by 1 degree FCalorie is the metric unit of heat quantity. It is heat needed to raise temperature of 1 gm of water by 1 deg C Cal = 1 kilo calorie (K Cal)1TR = BTU = 3000 K Cal
2AIR CONDITIONING IN TODAY'S CONTEXT: In hot climate the air has to be cooled,in cold climate the air has to be heated,in dusty space the air has to be cleaned andIn all the above cases the air has to be properly distributed.Here air conditioning is required mainly for human comfort.But some times for other purposes like manufacturing goods, medicine, textiles etc the temperature and humidity control may vary. For this purpose also air conditioning is required.
4AIR CONDITIONING PROCESS Controlling the quality of indoor air for the benefit of Human comfort, human health and performance of equipment /process.Human comfort is related to the control of temperature, humidity and air movement.A process called REFRIGERATION controls the temperature and humidity.The human health is related to the control of dust, pollutants and other contaminants. This is achieved by filtration or by dilution of air.
5DEFINITIONSprocess of treating air and simultaneously controlling temp, humidity, impurities and distribution for comfort and health of human being and/ or for the industrial process permitting the best product yield during manufacture and storage.Process, which heats, cools, cleans and circulates air and controls its moisture content, simultaneously and on a year round basis.Science, which deals with supplying and maintaining desirable internal atmospheric conditions irrespective of external conditions. Temperature control, humidity control, air movement & circulation, air filtering/ cleaning/ purification.
6TEMPERATURE CONTROL Temperature most suited to majority of people It varies in summer (20 to 23 deg C) and winter (18 to 22 deg C) due to body temperatureOffice, club, lounge etc – 24.5deg CResidence, Hotel rooms, Guest house etc – 24deg CShops, super markets, Cinema halls, Public places – 23.5deg CMajor operation theatre – 21deg CComputer rooms, Laboratories etc – 22deg C
7HUMIDITY CONTROL Amount of moisture present in air Varies from place to place & time to timeCoastal areas are more humidDEHUMIDIFICATIONRemoval of excess moisture from the airHUMIDIFICATIONAdding moisture to any volume
8RELATIVE HUMIDITYRatio of amount of water vapour present in air to maximum amount of vapour the air can hold in a given temperatureIf the temperature increases the capacity to hold moisture also increasesAt 70°F, 8 grains = 100%. At 80°F, 11 grains = 100%.To increase RH, increase actual moisture content or decrease the temperature of the air.To decrease RH, decrease the moisture content or increase the temperature of the air.100% indicates the saturation level
9Human comfort – %Pharmaceutical – %Computer lab etc – %Spinning & weaving – %Low humidity - the air has very less moisture content. The air has tendency to absorb moisture from the surrounding.High humidity – uncomfortable, reduces evaporation process through skin and in turn cooling of body. Our body maintain comfort by perspiration as in coastal weather
10AIR MOVEMENTKeeps the body comfortable during hot weather. Increase in air movement results in,Increase of evaporation process as the moisture of skin evaporates fasterIncrease of convection process as the warm air next to the body is carried up faster.Increase of radiation process due to removal of heat from the surrounding surfacesDecrease in air movement decreases evaporation, convection and radiation which, decreases heat removal process from our body, keeps the body comfortable in cold weatherAir movement is created by - fans or blowers, through ducts for even distribution
11VENTILATION IN AC AREAS It is supply of fresh air, its circulation and distributionSame air cannot be re-circulated again and again. After some time some fresh air may be added for human comfort. This is done through a cowl (small opening) in AHU room.In rooms provided with window AC system always allow some fresh air when ac is not being used.
12DUST CONTROL DUST CONTROL IN AC AREAS Dust enters ac areas through openings like door etcThrough occupantsUse different types of filters
13PURITY & FILTERS: Air to be free from dust, dirt and other impurities Clean air for breathing and human healthIn food product manufacture place dirt, germs create harmful effectsClean air needed in manufacturing processesClogging of dirt etc., may create serious hazards to machinery partsTo maintain purity Air filters are used.Filters are normally located in R.A. pathVarious filters effectively reduce the above hazards
14FILTERS All air filters can be divided into five basic types. Dry filtersViscous impingement filtersElectronics filtersChemical filtersCarbon filtersSubmission particulate “absolute” filters
151 Dry filtersThey separate dust, pollen and bacteria by using fabrics of woven cotton, wool, felt, cellulose or fiber glass.The filter is supported in wire or angle frame located in return air path.Fiber glass media is less expensive and very widely used.Confined to smaller systems. Sizes x 450, 500 x 500, 600 x 600, etcAirflow required is up to 5-metre cube per second.Permanent dry typeEfficiency 95%. Materials – fabrics processed from plastics or brush type.Serviced by washing or by compressed air or vacuum cleaning.
16Dry filters Dry replaceable media type Efficiency 95%. Fabric media over metal frameServiced by replacing the media.Used as main filter or as pre filter to high efficiency filters.Throwaway type –Efficiency up to 95%. Used in smaller plantsPanels with filter media of fabrics, plastics, glass or metal fibre over wood or metal frame.Standard filter -a) Metallic filter – ½”, 1”, 13/4” thick.b) Polypropylene coir filter – ¼” thick.These are used in simple applications of comfort A/c.It can be used in central, packaged and window units.Dust filteration is up to 25 to 30 microns.
172 VISCOUS IMPINGEMENT FILTERS screen or mesh in a metal frame.Glass fibre or other fiber filter medium covered with viscous adhesive or oil film to retain dust particles.Metal media impingement filters are washed with hot water / steam / solvent to remove dust particles. Later it is cleaned with oil solution.Expensive Impingement filter - available in automatic roll modelsViscous impingement filter –Efficiency 80 – 90% Used for industrial or engine air taker.Serviced by washing and reoiling.Automatic air filters -Efficiency up to 90%. Used for larger systems.Operation normally time switch controlled.Deposited dust can be removed manually.
18Self Cleaning Viscous Type Air Filter (Oil Wetted) For removal of coarse and abrasive dust usually used as first stage filter in industrial application. To remove fibrous dust from the main air stream. very tough and rigid Area like Cotton/ Textile/ Jute/ Mills, Steel & Cement Plants, Fertilizer Units, DG set house etc. Self cleaning in nature, easy/ low maintenance Available on various designs in multiple sizes to suit clients exact requirements .
193 ELECTRONIC FILTERSHigh voltage used to attract dust particles over electrically charged plates installed in the return air path.Impingement filters as pre-filter to remove coarse dust particles & to create constant pressure across the plates.Removes smoke & fine particles, initial cost is high.
20Electrostatic cleaners Achieve optimum filtration level down to 0 Electrostatic cleaners Achieve optimum filtration level down to 0.1 micron. To be backed by microwave filters or pre filters Booster fan is not necessary for this
21ELECTROSTATIC FILTER 1. Dirt Laden Air 2. Pre-Filter Screen 3 ELECTROSTATIC FILTER 1. Dirt Laden Air 2. Pre-Filter Screen 3. Electronic Filter Cell 4. Activated Carbon Filter 5. Circulating Fan 6. Clean Fresh Air
22NASAL AIR FILTER This Indian patented product is not yet produced in India. It is available in other countries for the use of people. In India it has a large market as the dust pollution is at it's high in the Indian cities. People and Children are exposed to the pollution, dust and stink which causes severe health problems. This simple, soft, disposable, cost effective ( Rs 2/-per one day use) filter have a market of 10 million in Indian cities daily. Gives you a pleasant fragrance always when you walk through dusty smelly road sides, and while talking to others you are protected form airborne communicable diseases. I am ready to sell the patent right to the reputed company who wish to produce and market the filter in India.
234 CHEMICAL FILTERSconsists of a belt with nozzles on top.Nozzles spray solution of glycerine, germicide and odour absorbing chemicals.Absorbs dust, dirt, bacteria,odour etc.Solution collected in a basin at the bottom & When saturated with contaminants, cleaned by chemicals and recirculated.Very expensive and used in hospitals etc.
245 CARBON FILTERS To remove objectionable odor from the air. Useful when outside air pollutedUseful when same air is re-circulated continuouslyCarbon pack filter –To remove odours, fumes, vapours, gasses, etc.Carbon is activated and this filter quickly clogged with atmospheric dust.As per the manufacturers recommendation throwaway type OR reusable type may be adopted
26ACTIVATED CARBON FILTER Activated Carbon - Odour Absorbing Filter The simple human activated carbon filter naturally absorbs odors. After extended use, the filter's odor absorbing ability can be recharged by placing it in direct sunlight. HOW TO USEsimply peel off the double-sided adhesive tape on the back of the filter and attach to a clean surface area where there are odors, such as the underside of your trash can's lid or inside a cabinet door
276 ABSOLUTE FILTERSPleated continuous sheet of filter of glass-asbestos medium with ply wood, metal frame. The pleats are separated by corrugated paper or aluminum foil inserts.Used to filter airborne contaminants to protect life, to recover valuable products or in clean roomsHospitals - to remove bacteria, Atomic reactors - to remove radioactive dust, Food and drug plants - to provide sterile airDry filter as pre-filter to remove coarse dust particle for better efficiency.
28HIGH EFFICIENCY PARTICULATE AIR (HEPA) OR ABSOLUTE FILTERS For filtration below 5 microns. Filter particles down to 0.3 microns. Used in central A/c, package unit, etc.Booster fans are needed for this. Microwave and metallic filters as pre-filtersMicrovee filterDust filtration up to 5 microns.For computer rooms, operation theatre etcIncorporated in central, packaged units
29HIGH EFFICIENCY PARTICULATE AIR (HEPA) OR ABSOLUTE FILTERS
30SELECTION FACTORS for FILTERS Flow rate of the filter.Face velocity of filter ( air in m/s entering the effective face of filter).Resistance i.e., difference between static pressure upstream and downstream specified for clean and dirty conditions.Efficiency of filterDust holding capacityEconomy, durability and maintenance.Fire safety.
31LOCATION AND INSTALATION OF FILTERS Before cooling coil to protect from dustFor high degree filtration two filters - Pre filters at down stream & regular filter before cooling coil or up stream.Avoid fresh air intake through roof surface & from fume and odor.Servicing accessibility for filter cleaningA meter after filter to change or clean filter mediumAll ducts should be clean before the filters are cleaned.Air tight filter frame to prevent percolation of dustDoor and hatches giving access to live high voltage conductors of electrostatic precipitator should be equipped with locks.
33WINDOW AIR CONDITIONERS Compressor, condenser, fan, evaporator, capillary tube in a single unitFixed on any external wall or a window (blocks light partially)5 deg slope to exterior is needed for easy flow of condensate waterFixing location should serve best possible air circulationHermetically sealed (air tight steel shell with compressor and motor) reciprocating, scroll or rotary type compressor is usedPrecaution to be taken for hot air released by condenserNoisy and no uniform air circulation but economicalLower level fixing helps in easy maintenance and operationFor narrow / long room - high level installation - better air circulationAdjustable grills are provided to direct air movementAvailable from 0.5 to 2 TR suitable for 5 to 20 SqmLarger spaces to be handled by multiple units‘Filter clean reminder’ notice & sleep mode facility
35Window Air Conditioner with Electronic Controls Ideal for large-size rooms up to 1672 square feet, delivers a 2TR cooling capacity and an energy-efficiency rating of 9.4 electronic controls - full-function remote capabilities, simple to operate, variable-speed fan, multiple air direction, energy saver and sleep modes, 24-hour on/off timer, and auto cool offer a filter-check reminder and clean-air features
36WINDOW AC UNIT AND COOLING CYCLE For every sq m 200 btu (0 WINDOW AC UNIT AND COOLING CYCLE For every sq m 200 btu (0.6 TR) is needed as a thumb rule
39WINDOW AC UNITAdvantages-Each room can be controlled with required humidity & temperature.Ducts are eliminatedNo plumbing work needed.Simple, low cost & easy to installDisadvantages-Noisy & servicing is neededRequires an external windowOccupies space in windowAesthetically pleasingDistribution not uniform
40WORKING PRINCIPLE OF WINDOW AC AIR CYCLE in Window ACEvaporator with cooling coil consists of cold refrigerantThe Fan blows air in to the room through grillesDuring this process the air is dehumidified to some extent and moisture is collected in trayThe used air or hot air from the room enters the unit through filter at the lower portionThis air mixes with outside air and is blown by fan through evaporator as conditioned air to roomThis conditioned air is used by the occupants for comfort and the air cycle repeats
41REFRIGERATION CYCLE in Window AC Evaporator - cold refrigerant with low pressureAir blows over it - cooled - refrigerant becomes hot vapor - under low pressureHot vapor - to compressor - pressure - hot & high pressure vapor – to condenser coilOut side air – blow over condenser coil - absorbs heat & become hot - vapor inside coil - liquid (under high pressure)High pressure Liquid refrigerant - capillary tube - pressure is released - becomes cold refrigerant - passed to evaporatorEvaporator - cold refrigerant - air is blown - conditioned, circulatedEvaporator - air partially dehumidified - water collected in a tray – to another tray below condenser - evaporates - cools condenserCompressor, condenser - outer portion - cools from outside air through fan - position - to reduce the noise to interiorcontrol panel - controls refrigerant temp - human comfort.
42COMPARISON OF UNITARY SYSTEM WITH CENTRAL SYSTEM Saves installation and labourReqd temp of each room is metZoning, distribution, duct eliminatdUnit run only where A/C is neededFailure restricted to particular rm.Easy to A/C the spaces in phases.Large area this works out costlyNoise/vibration cannot be elimintdMaintenance disturbs the room.CENTRAL SYSTEMInstallation cost is moreUniform throughout.Zoning, Ductwork is a must.Runs throughoutFailures disturbs all A/C area.A/C system - worked out - including future expansionEconomical for large areasRemote plant rm - eliminate noise, vibrationEasy maintenance
43SPLIT AIR-CONDITIONING UNIT Two units - indoor unit (IDU) & outdoor unit (ODU)IDU & ODU – linked by refrigeration tubing & electrical cablesODU can be mounted outside the roomODU - condenser, fan, compressor -reduce noiseIDU - evaporator and blower fanAvailable up to 5TRMany advantages over window unitNon-availability of suitable window or external wall, noisy interior etc
45SPLIT AIR-CONDITIONING UNIT Multiple units to cool 2 or 3 adjacent roomsFits well to the interior aestheticsoccupies space for ODUFrequent operation of doors may bring fresh air but not desirable for large spacesBest for executive cabins, show rooms, noise less commercial spaces etcHermetically sealed (air tight steel shell with compressor and motor) reciprocating, scroll or rotary type compressor is used
47SPLIT AIR-CONDITIONING UNIT Piping between IDU & ODUEnsure right distance between the two units, if increased the disadvantages are,The refrigerant pressure drops and decreases cooling capacityThe lubricant oil does not return to compressor & damages the compressor. (Provide oil trap at every 3m in suction line)Extra un-evaporated refrigerant in long tube flows back & damages the compressorInsulation cost increases for refrigerant pipingADVANTAGESElegant look, Add beauty to the interiorReduces noise level, Easy maintenanceElectronic control – precise, sleek, accurate control, saves power
48CONDENSATE WATER IN SPLIT UNITS Evaporator - moisture of the air accumulates as waterCollected in a pan and drained out by gravity / pump, slope neededMOUNTING OUTDOOR UNITGood air circulation - open space – good air movement - close to IDUSupport and structural care – servicing - railing, safety measureslocations - plinth protection, over sunshade, terrace, wall with supportsCare for ODU coastal regionsAvoid - condenser fan facing sea wind – reduce speedAvoid - close to ground - sand dust clogging the condenser coilsSupports coated with anticorrosive paintSwitch, electrical components - protected from moisture
49SPLIT AIR-CONDITIONING UNIT TYPES Floor mountedWall mountedCeiling mountedExposed typeHidden typeCassette type
50FLOOR MOUNTED on floor or a platform - elegant unit with grills Air throw is upwards - affect the furniture layout Occupies floor space - not very user friendly
58CEILING MOUNTED – EXPOSED Directly fixed to the ceiling - resembles floor mounted type but in ceilingEasy to fix - No false ceiling - Cord or cordless remote unit for controlTurbo splits are large type units (5TR) to cover large areasCEILING MOUNTED – HIDDENHidden in a box like unit or false ceiling - Additional cost - Interior looks bright and uniform - Cord or cordless remote unit for controlCEILING MOUNTED – CASSETTEMounted above false ceiling - Outlet grill flush with surface of false ceiling - Cord or cordless remote unit for controlSlim, occupies less space - placed directly above the required areaMultiple units - for larger spacesA small motorized pump to drain out condensate water
62The cold side, consisting of the expansion valve and the cold coil, is generally placed into a air handler. The air handler blows air through the coil and routes the air throughout the building using a series of ducts. The hot side, known as the condensing unit, lives outside the building.A split-Ductable system air conditioner splits the hot side from the cold side of the system