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Mapua Institute of TechnologySchool of Mechanical and Manufacturing Engineering

ME152L-A1Group 1

Experiment no. 9

Air-Conditioning System

Atienza !eric" L. Grade2##$1#2%19ME-5&ate of 'erformance( #)*1+*12&ate of Su,mi ion( #)*19*12

Engr. eodulo A. /alle0n tructor

OBJECTIVES1. o ,e a,le to ac uaint our el e 3ith the ,a ic component of an air-

conditioning 4 tem2. o gain "no3ledge a,out the principle of operation of an air-

conditioning 4 tem.

THEORY AND ANALYSIS

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Air conditioner monitor and regulate the air temperature ia a thermo tat. he4 al o ha e an on,oard ;lter that remo e air,orne particulate from the

circulating air. Air conditioner function a dehumidi;er . ?ecau etemperature i a "e4 component of relati e humidit4 reducing thetemperature of a olume of humid air cau e it to relea e a portion of itmoi ture. hat@ 3h4 there are drain and moi ture-collecting pan near orattached to air conditioner and 3h4 air conditioner di charge 3ater 3henthe4 operate on humid da4 .Still the ma or part of an air conditioner manage refrigerant and mo e air int3o direction ( indoor and out ide(

• Evaporator - 7ecei e the li uid refrigerant•

Condenser - Bacilitate heat tran fer• Expansion valve - regulate refrigerant <o3 into the e aporator• Compressor - A pump that pre urize refrigerant

he cold ide of an air conditioner contain the e aporator and a fan that,lo3 air o er the chilled coil and into the room. he hot ide contain thecompre or conden er and another fan to ent hot air coming oC thecompre ed refrigerant to the outdoor . 0n ,et3een the t3o et of coilthere@ an expansion valve . 0t regulate the amount of compre ed li uidrefrigerant mo ing into the e aporator. Dnce in the e aporator the

refrigerant experience a pre ure drop expand and change ,ac" into aga . he compressor i actuall4 a large electric pump that pre urize therefrigerant ga a part of the proce of turning it ,ac" into a li uid. hereare ome additional en or timer and al e ,ut the e aporatorcompre or conden er and expan ion al e are the main component of anair conditioner.Although thi i a con entional etup for an air conditioner there are acouple of ariation 4ou hould "no3 a,out. =indo3 air conditioner ha e all

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he cold ide con i ting of the expan ion al e and the cold coil igenerall4 placed into a furnace or ome other air handler. he air handler,lo3 air through the coil and route the air throughout the ,uilding u ing aerie of duct . he hot ide "no3n a the conden ing unit li e out ide the,uilding.

he unit con i t of a long piral coil haped li"e a c4linder. 0n ide the coil ia fan to ,lo3 air through the coil along 3ith a 3eather-re i tant compre orand ome control logic. hi approach ha e ol ed o er the 4ear ,ecau eit@ lo3-co t and al o ,ecau e it normall4 re ult in reduced noi e in ide the

hou e at the expen e of increa ed noi e out ide the hou e:. Dther than thefact that the hot and cold ide are plit apart and the capacit4 i higherma"ing the coil and compre or larger: there@ no diCerence ,et3een aplit- 4 tem and a 3indo3 air conditioner.0n 3arehou e large ,u ine o>ce mall ,ig department tore and otherizea,le ,uilding the conden ing unit normall4 li e on the roof and can ,euite ma i e. Alternati el4 there ma4 ,e man4 maller unit on the roofeach attached in ide to a mall air handler that cool a peci;c zone in the,uilding.0n larger ,uilding and particularl4 in multi- tor4 ,uilding the plit- 4 temapproach ,egin to run into pro,lem . Either running the pipe ,et3een theconden er and the air handler exceed di tance limitation run that are toolong tart to cau e lu,rication di>cultie in the compre or: or the amountof duct 3or" and the length of duct ,ecome unmanagea,le. At thi pointit@ time to thin" a,out a chilled-3ater 4 tem.

Chilled- ater and Cooling-to er AC !nits

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Although tandard air conditioner are er4 popular the4 can u e a lot ofenerg4 and generate uite a ,it of heat. Bor large in tallation li"e o>ce,uilding air handling and conditioning i ometime managed a littlediCerentl4.Some 4 tem u e 3ater a part of the cooling proce . he t3o mo t 3ell-"no3n are chilled 3ater 4 tem and cooling to3er air conditioner .

• Chilled ater systems - 0n a chilled-3ater 4 tem the entire airconditioner i in talled on the roof or ,ehind the ,uilding. 0t cool 3aterto ,et3een +# and +5 degree Bahrenheit +.+ and %.2 degree8el iu :. he chilled 3ater i then piped throughout the ,uilding andconnected to air handler . hi can ,e a er atile 4 tem 3here the3ater pipe 3or" li"e the e aporator coil in a tandard air conditioner.0f it@ 3ell-in ulated there@ no practical di tance limitation to thelength of a chilled-3ater pipe.

• Cooling to er technology - 0n all of the air conditioning 4 tem3e@ e de cri,ed o far air i u ed to di ipate heat from thecompre or coil . 0n ome large 4 tem a cooling to3er i u edin tead. he to3er create a tream of cold 3ater that run through aheat exchanger cooling the hot conden er coil . he to3er ,lo3 airthrough a tream of 3ater cau ing ome of it to e aporate and thee aporation cool the 3ater tream. Dne of the di ad antage of thit4pe of 4 tem i that 3ater ha to ,e added regularl4 to ma"e up forli uid lo t through e aporation. he actual amount of cooling that anair conditioning 4 tem get from a cooling to3er depend on therelati e humidit4 of the air and the ,arometric pre ure.

?ecau e of ri ing electrical co t and en ironmental concern ome other aircooling method are ,eing explored too. Dne i oC-pea" or ice-coolingtechnolog4. An o -peak cooling 4 tem u e ice frozen during the e ening

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hour to chill interior air during the hotte t part of the da4. Although the4 tem doe u e energ4 the large t energ4 drain i 3hen communit4demand for po3er i at it lo3e t. Energ4 i le expen i e during oC-pea"hour and the lo3ered con umption during pea" time ea e the demand onthe po3er grid.Another option i geo-thermal heating. 0t arie ,ut at around ) feet 1.$meter : underground the earth@ temperature range from +5 to %5 degreeBahrenheit %.2 to 2 .$ degree 8el iu :. he ,a ic idea ,ehind geo-thermalcooling i to u e thi con tant temperature a a heat or cold ource in teadof u ing electricit4 to generate heat or cold. he mo t common t4pe of geo-thermal unit for the home i a clo ed-loop 4 tem. 'ol4eth4lene pipe ;lled3ith a li uid mixture are ,uried underground. &uring the 3inter the <uidcollect heat from the earth and carrie it through the 4 tem and into the,uilding. &uring the ummer the 4 tem re er e it elf to cool the ,uilding,4 pulling heat through the pipe to depo it it underground.

Bor real energ4 e>cienc4 olar po3ered air conditioner are al o ma"ingtheir de,ut. here ma4 till ,e ome "in" to 3or" out ,ut around 5 percentof all electricit4 con umed in the H.S. i u ed to po3er air conditioning of onet4pe or another o there@ a ,ig mar"et for energ4-friendl4 air conditioningoption .

Energ4 E>cient 8ooling S4 tem

?ecau e of the ri ing co t of electricit4 and a gro3ing trend to Igo green I

more people are turning to alternati e cooling method to pare theirpoc"et,oo" and the en ironment. ?ig ,u ine e are e en umping on,oard in an eCort to impro e their pu,lic image and lo3er their o erhead.0ce cooling 4 tem are one 3a4 that ,u ine e are com,ating highelectricit4 co t during the ummer. 0ce cooling i a imple a it ound .Large tan" of 3ater freeze into ice at night 3hen energ4 demand arelo3er. he next da4 a 4 tem much li"e a con entional air conditionerpump the cool air from the ice into the ,uilding. 0ce cooling a e mone4cut pollution ea e the train on the po3er grid and can ,e u ed along idetraditional 4 tem . he do3n ide of ice cooling i that the 4 tem areexpen i e to in tall and re uire a lot of pace. E en 3ith the high tart-upco t more than ### 4 tem are in u e 3orld3ide.An ice cooling 4 tem i a great 3a4 to a e mone4 and con er e energ4,ut it price tag and pace re uirement limit it to large ,uilding . Dne 3a4that homeo3ner can a e on energ4 co t i ,4 in talling geo-thermalheating and cooling 4 tem al o "no3n a ground ource heat pumpGS6':. he En ironmental 'rotection Agenc4 recentl4 named geo-thermal

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air conditioning proce e i to pro ide a u>cient amount of fre h air atde ira,le temperature and humidit4. Dut ide air i ta"en in and dependingon it original temperature and humidit4 mu t undergo one or e eral of thefollo3ing proce e (

emperature 8ontrol

• 8ooling• 6eating

6umidit4 8ontrol

• &ehumidi;cation• 6umidi;cation

Air conditioning 4 tem allo3 performing all of the e proce e and thep 4chrometric anal4 i illu trate the change in propertie of the airconditioning proce e .

Approaches to Temperature Control emperature control in an air conditioning 4 tem i achie ed ,4 pa ing theair through the cooling or heating coil 3hich ma4 u e an4 of the follo3ingapproache (1. /ar4 the temperature of air upplied to the pace 3hile "eeping theair<o3 rate con tant. hi i the ,a ic con tant olume aria,letemperature approach.2. /ar4 the air<o3 rate 3hile "eeping the temperature con tant for airupplied to the pace. hi i the aria,le olume con tant temperatureapproach.. /ar4 the air<o3 rate and change the temperature for air upplied to thepace. hi i the aria,le olume and temperature approach.+. /ar4 ,oth the uppl4 air temperature and <o3 rate 3here the air<o3 ratei aried do3n to a minimum alue then energ4 input to reheat the coil icontrolled to ar4 the uppl4 air temperature. hi i the aria,le olumereheat approach.

Approaches to +umidity Control 6umidit4 control in a conditioned pace i done ,4 controlling the amount of3ater apor pre ent in the air in the pace. =hen relati e humidit4 at thede ired temperature et-point i too high dehumidi;cation i re uired toreduce the amount of 3ater apor in the air for humidit4 control. Similarl43hen relati e humidit4 at the de ired temperature et point i too lo3humidi;cation i re uired to increa e the amount of 3ater apor in the air forhumidit4 control.

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8ommonl4 u ed dehumidi;cation method include(1. Surface dehumidi;cation on cooling coil imultaneou 3ith en i,lecooling.2. &irect dehumidi;cation 3ith de iccant-,a ed dehumidi;er6umidi;cation i not al3a4 re uired in an 6/A8 4 tem ,ut 3hen re uired

it i pro ided ,4 a humidi;er. 8ommonl4 u ed humidi;cation methodinclude(1. =ater pra4 humidi;er2. Steam pan humidi;er

AI( C$&)ITI$&I&' S*STEM )ESI'&0n de igning air conditioning 4 tem the ;r t challenge i to under tand thecomponent that aCect the ,uilding heat gain or heat lo - thi proce icalled heating or cooling load e timation. he reacti e challenge i toIde ignI controlled proce e to maintain the de ired condition or tate-point3ithin the occupied pace - the e are u uall4 called the 4 tem proce e

that u e p 4chrometric .

Estimating Cooling , +eating %oadLoad e timate are the ummation of heat tran fer element into gain : orout of lo e : the pace of a ,uilding. Each heat tran fer element i calledload component 3hich can ,e a em,led into one of three ,a ic groupexternal pace load internal pace load and 4 tem load . o properl4under tand the 3or"ing of the ariou external internal and 4 tem loadcomponent the follo3ing item need to ,e gathered from a et of planexi ting ,uilding ur e4 or occupant inter ie3 (J ?uilding uare-footage and olumeJ Drientation of the ,uilding un eCect on urface :J ear round 3eather data de ign condition heat tran fer:J H e of the pace 3ithin the ,uilding o>ce conference room la, datacenter: J 6our of operation occupied and unoccupied:J hermo tat et point main comfort parameter:J &imen ion of 3all roof 3indo3 and doorJ 8on truction material gather den itie external color and H-factor orde cri,e material t4pe la4er ,4 la4er 7- alue :J Stair3a4 and ele ator <oor-to-<oor opening :J 'eople occupanc4 and acti it4 and 3hen the4 are pre entJ Lighting inten it4 and hour u edJ Motor and appliance ize or "= and time the4 are u edJ /entilation need 0AK and exhau t ma"eup:

he total cooling load i than determined in "= or ton ,4 the ummation of all of the calculated heat gain . Along 3ith p 4chrometric load e timatinge ta,li he the foundation upon 3hich 6/A8 4 tem de ign and operationoccur.

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Dne ton i e ui alent to heat extraction rate of 12### ?tuF *hr and 1 "= ie ui alent to +1+ ?tuF *hr.

)etermine )esign Supply Air o (ate6/A8 engineer u e p 4chrometric to tran late the "no3ledge of heating or

cooling load 3hich are in "= or ton : into olume <o3 rate in m * or8BM: for the air to ,e circulated into the duct 4 tem. he olume <o3 rate iu ed to determine the ize of fan grill outlet air handling unit andpac"aged unit . hi in turn aCect the ph4 ical ize foot print: of airhandling unit and pac"age unit and i the ingle mo t important factor inconceptualizing the pace re uirement for mechanical room and al o theair-di tri,ution duct .

he main function of the p 4chrometric anal4 i of an air-conditioning4 tem i to determine the olume <o3 rate of air to ,e pu hed into theducting 4 tem and the izing of the ma or 4 tem component . =e 3illtud4 thi in detail ,ut ,efore that letF ;r t refre h ome elementar4p 4chrometric .

"S*C+($MET(ICS' 4chrometric i the cience of tud4ing the thermod4namic propertie ofmoi t air. he amount of moi ture apour in the air arie uite igni;cantl4under diCerent condition . =hen the air i hot it can contain a large amountof moi ture apour ometime a much a 5 ,4 olume. =hen it i cold itcapacit4 to hold the moi ture i reduced. =hen the temperature of 3arm air,egin to fall the apour al o cool and if cooling continue it 3ill conden einto tin4 moi ture droplet . 0n the atmo phere thi re ult in the formation ofcloud and e entuall4 rain.

)e.nitions of Air hree ,a ic de;nition are u ed to de cri,e air under ariou condition (1. Atmo pheric air - contain nitrogen ox4gen car,on dioxide 3ater aporother ga e and mi cellaneou contaminant uch a du t pollen andmo"e. hi i the air 3e ,reathe and u e for entilation.2. &r4 air - exi t 3hen all of the contaminant and 3ater apor ha e ,eenremo ed from atmo pheric air. ?4 olume dr4 air contain a,out %$ percentnitrogen 21 percent ox4gen and 1 percent other ga e . &r4 air i u ed athe reference in p 4chrometric .. Moi t air - i a mixture of dr4 air and 3ater apor.Bor practical purpo e moi t air and atmo pheric air can ,e con iderede ual under the range of condition normall4 encountered.

"sychrometric Chart

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he ' 4chrometric 8hart pro ide a graphic relation hip of the tate orcondition of the air at an4 particular time. 0t di pla4 the propertie of air( dr4,ul, temperature ertical line : 3et ,ul, temperature line loping gentl4do3n3ard to the right: de3 point temperature horizontal line : andrelati e humidit4 the cur e on the chart:. Gi en an4 t3o of the epropertie the other t3o can ,e determined u ing the chart. he chartFu efulne lie ,e4ond the mere repre entation of the e elementar4propertie Nit al o de cri,e the airF moi ture content far right cale:energ4 content outer diagonal cale on upper left: peci;c olume lineloping harpl4 do3n3ard to the right: and more.

!ses of "sychrometric Chart he p 4chrometric chart con e4 an amazing amount of information a,outair. 0t pro ide an in alua,le aid in illu trating and diagno ing en ironmentalpro,lem uch a 3h4 heated air can hold more moi ture and con er el4ho3 allo3ing moi t air to cool 3ill re ult in conden ation. o predict 3hetheror not moi ture conden ation 3ill occur on a gi en urface 4ou need threepiece of information the temperature of the air the relati e humidit4 of theair and the urface temperature. he p 4chrometric chart explain that ,4rai ing the urface temperature or ,4 lo3ering the moi ture content of theair or emplo4 ome com,ination of ,oth can a oid urface conden ation. Arule of thum, i that a 1#OB ri e in air temperature can decrea e relati ehumidit4 2# percent. H e of a p 4chrometric chart 3ill ho3 that thi i true.

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A p 4chrometric chart al o help in calculating and anal4zing the 3or" andenerg4 tran fer of ariou air-conditioning proce e . 0n practicalapplication the mo t common p 4chrometric anal4 i made ,4 6/A8contractor in ol e mea uring the dr4 and 3et ,ul, temperature of airentering and lea ing a cooling coil. 0f the e temperature are "no3n along3ith the olumetric air <o3 rate 8BM: through the coil the cooling capacit4of a unit can ,e eri;ed. H ing the dr4 and 3et ,ul, temperatureinformation t3o point can ,e located on a p 4ch chart and thecorre ponding enthalp4 alue read for them. he total ? H6 coolingcapacit4 can then ,e determined ,4 multipl4ing +.5 time the 8BM aluetime the enthalp4 diCerence of the t3o air tate point Pi.e. +.5 8BM QhR.8ontractor often ha e to perform thi calculation to pro e that theire uipment i 3or"ing ati factoril4.

QUESTIONS AND ANSWERS/0 What is an Air conditioning1Air conditioning i the remo al of heat from indoor air for thermal comfort.20 What is psychometry1' 4chrometric i the cience of tud4ing the thermod4namic propertie ofmoi t air.30 What is meant 4y or degree of saturation10t i the ratio of humidit4 ratio of moi t air - to humidit4 ratio of aturatedmoi t air at the ame temperature and pre ure.50 Enumerate and discuss the components of an air-conditioning0

• Evaporator - 7ecei e the li uid refrigerant• Condenser - Bacilitate heat tran fer• Expansion valve - regulate refrigerant <o3 into the e aporator• Compressor - A pump that pre urize refrigerant

60 )e.ne the follo ing terms7a0 Saturated air- he air con i t of the 3ater apor or

moi ture at all time no matter 3hat it temperature andpre ure i .

40 (elative humidity- 0t i de;ned a the ratio of the maof 3ater apor pre ent in the unit olume of the air at

certain temperature to the maximum ma of the 3aterapor that can ,e accommodated in the unit olume of air3hen it i aturated.

c0 Wet and dry 4ul4- he &r4 ?ul, temperature u uall4referred to a air temperature i the air propert4 that imo t common u ed. =hen people refer to the temperatureof the air the4 are normall4 referring to it dr4 ,ul,temperature. he Wet Bul4 temperature i the

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temperature of adia,atic aturation. hi i thetemperature indicated ,4 a moi tened thermometer ,ul,expo ed to the air <o3.

d0 )e point temperature- he )e "oint i thetemperature at 3hich 3ater apor tart to conden e out

of the air the temperature at 3hich air ,ecomecompletel4 aturated:

CONCLUSION0 3a a,le to familiarize m4 elf 3ith the ,a ic component function

and operation of an air conditioning 4 tem. Air conditioning 4 temF mainfunction i to cool an enclo ed en ironment for thermal comfort. 0t i al ou ed to control the ualit4 of air 3ithin that enclo ed en ironment.' 4chometr4 i the cience of tud4ing the thermod4namic propertie ofmoi t air.

0 conclude that air conditioning 4 tem i er4 important to human

ince it aCect u in man4 3a4 . 0t aCect our mood ho3 3e perform anddrain our energ4 and therefore load e timation air di tri,ution ande uipment election are important in de igning an air conditioning 4 tem.

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REFERENCES

http(**home.ho3 tuC3or" .com*ac%.htmhttp(**333.cedengineering.com*upload*Air 2#8onditioning2#' 4chrometric .pdf

http(**en.3i"ipedia.org*3i"i*Air conditioning

http(**333.engineeringtool,ox.com*moi t-air- aturation-d )$5.html

http(**333.engineeringtool,ox.com*dr4-3et-,ul,-de3-point-air-d )$2.html