17 refrigeration done

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Last Rev.: 12 JUN 08 REFRIGERATION CYCLE ANALYSIS : MIME 3470 a!e 1

Grading Sheet~~~~~~~~~~~~~~

MIME 3470—Thermal Science Laboratory

~~~~~~~~~~~~~~

Laboratory №. 7

! E"!IGE!#TI$% &'&LE #%#L'SIS

St(dent)* %ame) + Section №

,$I%TS S&$!E T$T#L,!ESE%T#TI$%—#--licable to oth MS /ord and Mathcad Section)

GE%E!#L #,,E#!#%&E $!G#%I1#TI$% E%GLIS2 + G!#MM#!

$!E!E #T# &#L&5L#TI$%S 6 !ES5LTS

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&#L&5L#TE

ideal

OACOP 6

act

OACOP 0

TE&2%I&#L /!ITTE% &$%TE%T

IS&5SSI$%—GE%E!#L IS&5SSI$% $" &#L&5L#TI$%S E;,L#I% I% TE!MS $" ST 6 <% L#/S T2E IS&!E,E%&IES

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MIME 3470—Thermal Science Laboratory

~~~~~~~~~~~~~~

Laboratory №. 7

! E"!IGE!#TI$% &'&LE #%#L'SIS~~~~~~~~~~~~~~

L# ,#!T%E!S? %#ME %#ME

%#ME %#ME

%#ME %#ME

SE&TI$% №E;,E!IME%T TIME+#TE? TIME #TE

~~~~~~~~~~~~~~

$@E&TI=E —of this exercise is to determine the variouscoefficients of performance, COP . Specifically, these are the idealand actual cycle COP s using the attached thermodynamic diagramfor Refrigerant-12 (R12).

I%T!$5&TI$% — refrigeration cycle is a cycle !hichtransfers heat from a lo! temperature sin" to a high temperaturesin" #y the application of energy from a third source. refrigeration cycle differs from !hat is commonly called a heat

pump in that the desired output is the heat transfer from the coldsin" rather than the heat transfer to the hot sin".

$he most common type of refrigeration cycle is the mechanicalvapor compression cycle. $his cycle is essentially a Ran"ine

%ycle run #ac"!ards. schematic and a T-s diagram of the cycleappears in &igure 1. $he cycle is referred to as a mechanicalcompression #ecause the compression process (States 1 to 2) isaccomplished #y a mechanical compressor that is driven #y anexternal po!er source. $his source is usually an electric motor.

"ig(re — Schematic and T-s -roce)) diagram oA an ideal

Ba-orCcom-re))ion reArigeration cycle

#%#L'SIS —$he performance of a refrigeration cycle is given interms of the Coefficient of Performance or COP and the cooling

capacity evapQ . $he overall COP for the cycle is

compevapOA W QCOP = 8:

!here, compW 'electric po!er to the compressor motor.

&rom the &irst a!, the cooling capacity is

evapevapair evap out in pair evap T T cmQ −= 8<:

!here, evapair m

'mass flo! of air through the evaporator

air pc ' specific heat of air

evapinT ' temperature of air entering the evaporator

evapout T ' temperature of air leaving the evaporator

$he refrigeration cycle in &igure 1 is an ideal cycle. t is ideal #ecause the compression process is isentropic (States 1 to 2) andthere are no pressure losses across either the evaporator (States *to 1) or the condenser (States 2 to +). $he po!er to the compressor and the cooling capacity for the ideal refrigeration cycle are

•

•

Evaporator

Condenser

Valve

Throttling

Expansion

:8

cond Q

evapQ

T

s

hConstant

pConstant

pConstant

•

•

•

•

•

•

Compressor

compW




( )12 hhmW Rcomp −= 83:

( )*1 hhmQ Revap −= 84:

!here, Rm ' mass flo! of refrigerant through the system.

$herefore, from uation 1, the ideal COP is

12

*1

hh

hh

W

QCOP

comp

evapOAideal −

−==

. 8:

"ig(re <— Schematic and T-s diagram Aor a Ba-orCcom-re))ion

reArigeration cycle incl(ding irreBer)ibilitie) in all com-onent)

$he refrigeration cycle for an actual cycle is presented in &igure 2.

$his cycle varies from the ideal in that the compression process isnon-isentropic (States 1 to 2) and there are pressure losses across

#oth the evaporator (States to /) and the condenser (States + to *).

$he cooling capacity, evapQ , and the heat load from the condenser,

cond Q , are

( )./ hhmQ Revap −= 8D:

and ( )*+ hhmQ Rcond −= 87:

and ( )cond cond air out in pair cond T T cmQ −=

8:

uation / is o#tained from an energy #alance across the air

side of the condenser. $he temperatures cond inT and cond out T are

the air temperatures in and out of the condenser.uation + !ould #e valid for an actual cycle only if the

compression and com#ination compressor-motor efficiencies !ere

#oth unity. $he compression efficiency, compη , and the

compressor-motor efficiency, mc-η , are defined #y

12

12

hh

hh scomp

−

−=η 8:

and( )

comp

s Rmc

W

hhw

12

-

−=η 80:

$herefore, the cycle overall COP for actual cycle is

12

./

hh

hhCOP

act

OA−−= 8:

,!$&E5!E — $urn on and study the cycle and the components of the refrigeration unit sho!n in &igure +. $race the R12 flo! path andidentify the compressor, evaporator, condenser, and expansion valveinlets and outlets. 0a"e sure that the flo! path is correct #y openingand closing the proper valves. &or the unit to act on a refrigerationcycle, the flo! from the evaporator must go to the top of thecompressor.

fter the unit has sta#ilied, ta"e temperature and pressure data

for flo!s into and out of thea. %ompressor (States 1 and 2). %ondenser (States + and *)c. xpansion valve (States and 3)d . vaporator (States and /).

"ig(re 3— !eArigeration cycle eF-erimental )et(-

"or the !e-ort

%$TE? Thi) eF-eriment i) to be done in Engli)h (nit) only.

$his is #ecause the only pressure-enthalpy diagram for &reon-12!e have access to is in nglish units.1. 0a"e a ta#le (supplied #elo!) of state properties ( p, T , v, h,

and s) for the eight states of the cycle. 2. 4n the supplied p-h chart, plot the ideal cycle for the appro-

priate conditions of our experimental data. $he student is touse 5ressures + and / to determine the ideal cycle. e sure toindicate !ith #loc" arro!s across the lines the occurrences of

mQcond , mQevap , and mW comp .

+. Redo tem 2 using the actual cycle data points. $his plotshould appear on the same sheet as that of tem 2.

*. %alculate

ideal

OACOP and

act

OACOP

. xplain in terms of the &irst and Second a!s of $hermodynamics, the nature of the discrepancies #et!een thecycle paths in tems 2 and +. re the discrepancies in the

proper direction(s)6 Should there #e differences #et!een theactual and ideal cycles6

$!E!E #T# &#L&5L#TI$%S and !ES5LTS REMEMBER: DO THIS ONE IN ENGLISH UNITS ONLY

!e(irement ? 0a"e a ta#le of state properties ( p, T , v, h, and s) for the eight states of the cycle.

State

ata

&om-re))or

&om-re))or

&onden)er

&onden)er

EF-an)ion

EF-an)ion

EBa-orator

EBa-orator

•

•

Evaporator

Condenser

cond Q

evapQ

T

s

••

•

•

•

•

Compressor

compW

1 p

/ p

2 p

•

•

••

•

•

•

•




In $(t In $(t =alBe In =alBe $(t In $(t

8 si :

gage

8 si :

ab)ol(te

8H4.7 si :

T 8! :

"8 ft 3+#$m:

%8 Bt&+#$m:

s8 Bt&+#$m⋅ R:

!e(irement 4.%alculate

ideal

OACOP and

act

OACOP .

$he student may !ant to use the 0athcad o#7ect (#elo!) for this. 4ther!ise, feel free to delete the o#7ect.

MATHCAD OBJECT--DOUBLE CKICK TO OPEN

YOU MAY NOT CHOOSE TO USE MATHCAD ON THIS LAB.

THE OBJECT IS PRESENTED IF YOU WANT IT.

OTHERWISE DELETE THE OBJECT.



Last Rev.: 12 JUN 08 REFRIGERATION CYCLE ANALYSIS : MIME 3470 a!e "

!e(irement) < 6 3. 4n the supplied p-h chart, plot the ideal cycle for the appropriate conditions of our experimental data. $he student is to

use 5ressures + and / to determine the ideal cycle. 8e sure to indicate !ith #loc" arro!s across the lines the occurrences of mQcond ,

mQevap , and mW comp . Redo tem 2 using the actual cycle data points. $his plot should appear on the same sheet as that

of tem 2.

m

Qcond

9 %:%%$; %:%



Last Rev.: 12 JUN 08 REFRIGERATION CYCLE ANALYSIS : MIME 3470 a!e #

IS&5SSI$% $" !ES5LTS

EF-lain in term) oA )t and <nd La) the di)cre-encie) beteen

the to -lot).

'ns(er:

#re the di)cre-encie) in the -ro-er direction)>

'ns(er:

Sho(ld there be diAAerence) beteen the act(al and ideal

cycle)>

'ns(er:

&$%&L5SI$%S




#,,E%I&ES

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State

ata

&om-re))or

In

&om-re))or

$(t

&onden)er

In

&onden)er

$(t

EF-an)ion

=alBe In

EF-an)ion

=alBe $(t

EBa-orator

In

EBa-orator

$(t

8 si : dT 8! : d

•

•

Evaporator

Condenser

cond Q

evapQ

•

•

Compressor

compW

•

•

•

•




#,,E%I; — !C< 8&& l<"<: T2E!M$'%#MI& ,!$,E!TIES "8 ft 3+#$m: &8 Bt&+#$m: %8 Bt&+#$m: s8 Bt&+#$m R:

Sat(rated

S(-erheated



Last Rev.: 12 JUN 08 REFRIGERATION CYCLE ANALYSIS : MIME 3470 a!e $




#,,E%I; &— I$G!#,2I& S9ET&2ES

The Father of CoolWillis Haviland Carrier—The History of Air Conditioning

8y 0ary 8ellis

< fish only for edi#le fish, and hunt only for edi#le game even inthe la#oratory.= — >illis ?aviland %arrier on #eing practical.

n 1@A2, only one year after >illis

?aviland %arrier graduated from %ornell;niversity !ith a 0asters in ngineer-ing, the first air (temperature and humi-dity) conditioning !as in operation,ma"ing one 8roo"lyn printing planto!ner very happy. &luctuations in heatand humidity in his plant had caused thedimensions of the printing paper to "eepaltering slightly, enough to ensure a mis-alignment of the colored in"s. $he ne!air conditioning machine created a sta#leenvironment and aligned four-color

printing #ecame possi#le. ll than"s tothe ne! employee at the 8uffalo &orge %ompany, !ho started on asalary of only B1A per !ee".

$he Cpparatus for $reating irD (;.S. 5atE /A//@) granted in1@A3, !as the first of several patents a!arded to >illis ?aviland%arrier. $he recognied Cfather of air conditioningD is %arrier, #ut theterm Cair conditioningD actually originated !ith textile engineer,Stuart ?. %ramer. %ramer used the phrase Cair conditioningD in a 1@A3

patent claim filed for a device that added !ater vapor to the air intextile plants—to condition the yarn.

n 1@11, >illis ?aviland %arrier disclosed his #asic Rational5sychrometric1

&ormulae to the merican Society of 0echanicalngineers. $he formula still stands today as the #asis in all funda-mental calculations for the air conditioning industry. %arrier said hereceived his Cflash of geniusD !hile !aiting for a train. t !as a foggynight and he !as going over in his mind the pro#lem of temperatureand humidity control. 8y the time the train arrived, %arrier had an

understanding of the relationship #et!een temperature, humidityand de! point.

ndustries flourished !ith the ne! a#ility to control the temperatureand humidity levels during and after production. &ilm, to#acco, pro-cessed meats, medical capsules, textiles and other products acuiredsignificant improvements in uality !ith air conditioning. >illis andsix other engineers formed the %arrier ngineering %orporation in1@1 !ith a starting capital of B+,AAA (1@@ sales topped B #illion).$he company !as dedicated to improving air conditioningtechnology.

n 1@21, >illis ?aviland %arrier patented the centrifugal refrigerationmachine. $he Ccentrifugal chillerD !as the first practical method of air conditioning large spaces. 5revious refrigeration machines usedreci-procating-compressors (piston-driven) to pump refrigerant

1 -)ychrometer n. ? a hygrometer consisting essentially of t!o

similar thermometers !ith the #ul# of one #eing "ept !et so that the coolingthat results from evaporation ma"es it register a lo!er temperature than thedry one and !ith the difference #et!een the readings constituting ameasure of the dryness of the atmosphere. -)ychrometric ad"#

-)ychrometry n#

%$T T$ E &$%"5SE /IT2

-)ychometry n# ? divination of facts concerning an o#7ect or itso!ner through contact !ith or proximity to the o#7ect.-)ychometric) pl# n# ut sing# in construction? the psychologicaltheory or techniue of mental measurement

httpFGG!!!.merriam-!e#ster.com

(often toxic and flamma#le ammonia) throughout the system. %arrier desig-ned a centrifugal-compressor similar to the centrifugal turning-

#lades of a !ater pump. $he result !as a safer and more efficientchiller.

%ooling for human comfort, rather than industrial need, #egan in1@2*, noted #y the three %arrier centrifugal chillers installed in theH.. ?udson 9epartment Store in 9etroit, 0ichigan. Shoppers

floc"ed to the air conditioned store. $he #oom in human coolingspread from the department stores to the movie theaters, mostnota#ly the Rivoli $heater in Ie! :or", !hose summer film

#usiness s"yroc"eted !hen it heavily advertised the cool comfort.9emand increased for smaller units and the %arrier %ompanyo#liged.

n 1@2/, >illis ?aviland %arrier developed the first residential

C>eatherma"erD, an air conditioner for private home use. $he Jreat

9epression and then >>2 slo!ed the non-industrial use of air conditioning. fter the !ar, consumer sales started to gro! again.

$he rest is history, cool and comforta#le history.

>illis ?aviland %arrier did not invent the very first system to cool an

interior structure, ho!ever, his system !as the first truly successful

and safe one that started the science of modern air conditioning.

Special than"s given to the %arrier %orporationhttpFGGinventors.a#out.comGli#raryG!ee"lyGaaA/[email protected]

/ILLIS &#!!IE!

#y Hohn ?. ienhard

t !as a hot ugust day in San ntonio, $exas. !as there to name the

0ilam 8uilding as a 0echanical ngineering andmar". !ent fromthe hot street into the cool halls of this fine old 21-story rt 9eco

#uilding. s if #y magic, the !eather changed from a!ful to pleasantas entered.

$his !as no ordinary magic. :ou see, this !as the first air-conditioned office #uilding in the !orld.

nside, met representatives of the %arrier %orporation. $hey !ere

proud this day. n 1@2/, their company installed the original systemhere. 4f course everyone invo"ed the name of >illis %arrier.

%arrierDs mother had some of that creative magic. &or she had amechanicDs instincts. %arrier learned a#out math and machines fromhis mother.

%arrier !as poor. ?e !aited ta#les, earned scholarships, and soldstereopticon slides to get through engineering school at %ornell. n1@A1, he !ent on to !or" for the 8uffalo &orge %ompany. $here hedesigned heating and cooling euipment.

?e soon sa! ho! little !e "ne! a#out regulating the temperature andhumidity of air.?e !ent to !or" on the pro#lem. 8y1@11, heDd !rittenthe science of psychrometry. t descri#es air temperature andhumidity.

8ut %arrier did much more. ?eDd already #egun creating a technologyfor controlling air condition. n 1@A, 8uffalo &orge sa! the value of his !or". $hey formed $he %arrier ir %onditioning %orporation of merica as a su#sidiary.

ir conditioning spread across merica. &irst theaters and churches.$hen more complex structures. f youDre old enough, you remem#er the early air-conditioned movie theaters. $hey used to paint #lue icecu#es on their maruees.

%arrier died in 1@A. Io! the ?ouston temperature clim#s. nd too say <$han" JodK= for the magic that ma"es this sultry climateso pleasant—all year round.

http://inventors.about.com/mbiopage.htm


http://www.merriam-webster.com/

http://inventors.about.com/gi/dynamic/offsite.htm?site=http://www.carrier.com/


http://inventors.about.com/library/weekly/aa081797.htm


http://www.uh.edu/engines/jhlbio.htm



http://www.merriam-webster.com/







ngines of 4ur ngenuity, L 3//httpFGG!!!.uh.eduGenginesGepi3//.htm

http://www.uh.edu/engines/epi688.htm



17 refrigeration done

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