Refrieration Unit Lab Report

Table of Contents

Abstract………………………………………………………………………………………2 Introduction…………………………………………………………………………………..3 Objective…………………………………………………………………………………….4 Theory……………………………………………………………………………………….5 Apparatus..………………………………………………………………………………….. !rocedures……………………………………………………………………………………"#$ %esults and calculation……………………………………………………………………… 'iscussion……………………………………………………………………………………25#2 Conclusion.............................................. Conclusion............................................................................ ............................................................ ..................................................2" ....................2" %eco((endation…………………………………………………………………………….2$ %eferences…………………………………………………………………………………...2& Appendices................................................... Appendices..................... ............................................................ ............................................................ .............................................3) ...............3)

Abstract

1

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The e*peri(ent of the refri+eration unit ,as conducted by usin+ -OT/0 (echanical heat pu(p and ther(odyna(ics refri+eration unit. The e*peri(ent conducted in five different ,ays to+ether ,ith their o,n objectives. The first one ,as to deter(ine the po,er input1 heat output and coefficient of perfor(ance of a vapour vapour co(pression heat pu(p syste( and the second one one ,as to produced the perfor(ance of heat pu(p pu(p over a ran+e of source and delivery delivery te(peratures. Then1 the third one ,as plotted the vapour co(pression cycle cycle on the p#h dia+ra( and co(pared it ,ith the ideal cycle and to perfor( ener+y balances balances for the condenser and co(pressor. co(pressor. Then Then follo,ed ,ith the fourth e*peri(ent e*peri(ent and the objective ,as to deter(ine the co(pression ratio and the volu(etric efficiency and the last e*peri(ent ,as to plot the perfor(ance of heat pu(p over a ran+e of evaporatin+ and condensation te(peratures ,hich are the saturation te(perature of the condensin+ pressure.













The -OT/0 -OT/0 echanical eat !u(p 6odel7 /859 has been desi+ned to provide students ,ith a practical and :uantitative de(onstration of a vapour co(pression cycle. %efri+erators %efri+erators and heat pu(p both apply the vapour co(pression co(pression cycle1 althou+h the applications of these (achines (achines is different but the co(ponents are essentially the sa(e. The echanical eat !u(p is capable of de(onstratin+ the heat pu(p application ,here a lar+e freely available ener+y source such as at(osphere is to be up+raded for ,ater heatin+. The refri+eration unit is capable to de(onstrate the result ,hen the flo, rate of the coolin+ ,ater adjusted to a certain nu(ber and it is allo, us to study the perfor(ance curve and the efficiency of refri+eration unit ,ith respect to varyin+ flo, rates. Other than that1 this apparatus ,ill help in the deter(inin+ the ener+y balances. The refri+eration unit apparatus is e:uipped ,ith control valves for the coolin+ ,ater flo, rate1 pressure1 te(perature te(perature and co(pressor po,er output display ,hich ,ill (a;e it easier to conduct the e*peri(ents ,ith the accurate data display. <2=













There are five sections in this refri+eration unit e*peri(ents. or the first part for this e*peri(ent the objective is to deter(ine the t he po,er input1 heat output and the coefficient of perfor(ance of a vapour co(pression heat pu(p and for the second part the objective is to produce the perfor(ance if heat pu(p over a ran+e of source and delivery te(peratures. e*t1 for the third part in this e*peri(ent is to plot the vapour co(pression cycle cycle on the p#h dia+ra( and co(pare ,ith ,ith the ideal cycle and also to perfor( the ener+y balances balances for the condenser and the co(pressor. co(pressor. or the fourth fourth part for this e*peri(ent is to deter(ine the co(pression ratio and volu(etric efficiency. astly1 astly1 for the last in this e*peri(ent is to plot the perfor(ance of the heat pu(p over a ran+e evaporatin+ and condensation te(peratures ,hich are the saturation te(perature of condensin+ pressure.













A heat pu(p is a (echanis( that absorbs heat fro( ,aste source or surroundin+ to produce valuable heat on a hi+her te(perature level than that of the heat source. The funda(ental theory of heat pu(ps is that heat absorbed by a (ediu( the release the heat at a re:uired te(peratures ,hich is hi+her after che(ical or physical transfor(ation. eat pu(ps are also desi+ned to transfer ther(al ener+y opposite to the direction of spontaneous heat flo, by absorbin+ heat fro( a cold space and release the heat to a ,ar(er space. eat pu(p uses so(e a(ount of e*ternal po,er to acco(plish the ,or; of transferrin+ ener+y fro( the heat source to the heat sin;. eat pu(p also one of the technolo+ies that capable to save ener+y and there are three types of heat pu(ps syste(s that is heat pu(p is closed cycle vapour co(pression co(pression heat pu(p such as electric and en+ine driven. The second type of heat pu(p is heat transfor(ers that is a type of absorption heat pu(p and the last types of heat pu(p pu(p is (echanical vapour reco(pression heat pu(ps pu(ps operatin+ at about 2))C. The (ost co((on e*a(ples of heat pu(ps is an air conditioners and a freeDers. The ter( Eheat pu(pF are +eneral and applies to (any @AC @AC 6heatin+1 ventilatin+ and air conditionin+9 devices used in space heatin+ or space coolin+. eat pu(ps are si(ply dra, heat fro( the ccoler e*ternal air or fro( the +round and in heatin+ (ode1 heat pu(p are three to four ti(es (ore efficient co(pared to the si(ple electrical resistance heaters in their use of electric po,er. The Coefficient of !erfor(ance1 6CO!9 of a heat pu(p cycle is an e*pression of the cycle efficiency and is stated as the ratio of the heat re(oved in the heated space to the heat ener+y e:uivalent of the ener+y supplied to the Co(pressor. CO! G eat re(oved re(oved fro( heated heated space H eat ener+y ener+y e:uivalent e:uivalent of the ener+y ener+y supplied to the Co(pressor Thus1 for the Theoretical -i(ple Cycle1 this (ay be ,ritten as7 CO! G

eatin+ /ffect eat of Co(pression

G 6h2  h39 6h2  h89













i+ure 8.87 -OT/0 echanical eat !u(p 6odel7 /859















8.8 Jenera Jenerall start#up start#up irst of all the refri+eration unit and all the instru(ents ,ere chec;ed it i s in +ood condition or not. The connection for both ,ater source and drain ,ere chec;ed. Then the ,ater supply opened and the coolin+ ,ater ,as set at 8 !. The connection bet,een the drain and the condensate collector ,ere chec;ed. or the last step ,ere the po,er supply ,as connected and the (ain po,er ,as s,itched on and follo,ed by the (ain s,itch at the control panel.

8.2 Jenera Jenerall shut#d shut#do,n o,n The co(pressor ,as s,itched off then follo,ed by the (ain s,itch and the po,er supply. s upply. Then1 the ,ater supply ,ere closed and ensured that the ,ater is not left runnin+.

8.3 /*peri(ent 87 'eter(ination of po,er input1 heat heat output and coefficient coefficient of perfor(ance. perfor(ance. The +eneral start#up procedures in 8.8 ,ere perfor(ed. The coolin+ ,ater flo, rate ,ere adjusted to 4)K. Then1 the syste( allo,ed to t o run for 85 (inutes. astly1 as tly1 all the necessary readin+s ,ere recorded into the e*peri(ental data sheet.

8.4 /*peri(ent 27 !roduction of heat pu(p perfor(ance perfor(ance curves over over a ran+e of sources and delivery te(perature. The +eneral start#up procedures in 8.8 ,ere perfor(ed. The coolin+ ,ater flo, rate ,ere adjusted to $)K and then allo,ed the syste( to run for 85 (inutes. All the necessary readin+s ,ere recorded into













The +eneral start#up procedure in 8.8. ,ere perfor(ed. The coolin+ ,ater flo, rate ,ere adjusted to 4)K and the syste( ,ere allo,ed to run for 85 (inutes. All the necessary ,ere recorded into the e*peri(ental data sheet and the e*peri(ent ,ere repeated at different co(pressor delivery pressure.

8." /*peri(ent 57 !roduction of heat pu(p perfor(ance perfor(ance curves over over a ran+e of evaporatin+ and condensation te(perature. The +eneral start#up procedure in 8.8 ,ere perfor(ed and the coolin+ ,ater flo, rate ,ere adjusted to $)K. Then1 the syste( ,ere allo,ed to run for 85 (inutes. All the necessary data or readin+ ,ere recorded into the e*peri(ental data sheet. e*t1 the e*peri(ent ,ere repeated ,ith reducin+ ,ater flo, rate so that the co(pressor delivery pressure increased for about ). bars and the evaporatin+ te(perature6TT49 ,ere (aintained by coverin+ part of the evaporator for the purpose of lo,erin the evaporatin+ loud. ast but not least1 the si(ilar steps ,ere repeated ,ith ,at er flo, rate ,ere not less than 2)K and the co(pressor delivery pressure ,as not e*ceeded 84 bars. The e*peri(ent ,ere repeated ,ith constant evaporatin+ te(perature6TT49.













/*peri(ent 87 'eter(ination of po,er input1 heat output and coefficient of perfor(anceL Coolin+ Mater lo, %ate 1 T8 Coolin+ Ma Mater ter lo, %ate 1 T8

K !

4) 2.)

Coolin+ Mater Inlet Te(perature 1 TT5 Coolin+ Mater Outlet Te(perature 1 TT Co(pression !o,er Input

 C C M

2&." 3).& 88

Calculation7

Coolin Cooling g water water flowrate , Coolin+ Mater Mater flo, rate 6 !9 G

Heat output =

1 L

min

x

100

1 kg 1 min 4180 J 1 L

x

60 s

x

kg.K

Heat output 83.6 W CO!h G Power input = 161 w =0.52

x 5 LPM =

x [ ( 30.9 −29.7 ) ] = 83.6

40 100

x 5 =¿ 2.)













Test Coolin+ Mater flo, %ate 1T8 K Coolin+ Mater lo, %ate 1 T8 ! Coolin+ Mater Inlet Te(perature1 TT5 C Coolin+ ,ater Outlet Te(perature1 C

8

2

3

2) 8.) 2&." 32.8

4) 2.) 2&.& 38.$

) 3.) 2&.& 38.8

TT Co(pressor !o,er Input eat Output CO!

85& 8".2 8.)52

85" 282 8.35

85 258 8.8

M M

Calculation7 Test 8 7

Coolin Cooling g water water flowrate , Coolin+ ,ater flo, rate 6!9 G

100

x 5 LPM =

ass flo, rateN ,ater G G 8))) ;+H( 3

8 (in

G ).)8" ;+Hs

8 (3 8))) 

8))) ;+ (

3

8 (in Convert G ) s

20 100

x 5 LPM =1.0













h2 Te(peratur ture T 6C9 3) 32.8 35

h 6;?H;+ H;+9 825."4 h2 84.4 h2G 834.52 ;?H;+

eat Output /in

G /out

0

G

ṁ6h 2 

h89

G ).)8" ;+Hs * 6834.52#824.4&9;?H;+ G ).8"2 ;?Hs CO! G 0 M G ).8"2H).85&

G8.)52

32.1 −30 35 −30

=

h 2−125,74 146.64 −125.74















ass flo, rateN 3

;+H(

Convert

3

2

8(

8))) ;+

8 (in

(in

8))) 

(3

) s

G

G ).)333 ;+Hs Calculation of h8 and h27 Interpolation (ethod ,as used 6refer to Table Table A#497 h8 Te(pera peratu ture re T 6C 6C99 25 25 2&.& 3)

h 6;?H 6;?H;+ ;+99 8)4.$3 h8 825."4

29.9 −25 30 −25

=

h 1−104.83 125.74 − 104.83

h 1=125.32

,ater G G 8)))













G).)333;+Hs * 6838.8"4#825.329 G ).282 CO!G 0HM G ).282H).85"G8.35 ).282H).85"G8.35 Test 31 Coolin+ ,ater flo, rate 6!9

Coolin Cooling g water water flowrate , G

100

¿

60 100

x 5 LPM

x 5 LPM =3 !

ass flo, rateN Convert

G

,ater G G 8))) ;+H( 3

3

8 (3

8))) ;+

8 (in

(in

8))) 

(3

) s

G ).)5 ;+Hs Calculation of h8 and h27 Interpolation (ethod ,as used 6refer

ble A#497













Te(pera peratu ture re T 6C 6C99 3) 38.8 35

h 6;?H 6;?H;+ ;+99 825."4 h2 84.4

31.1 −30 35 −30

=

h2G 83).34 ;?Hs

heat output 0 G ṁ6h2  h89 G).)5;+Hs * 683).34#825.329 683).34#825.329 G ).258 CO!G 0HM G ).258H).85G8.8 ).258H).85G8.8

Coefcient o perormance vs Temperature o water delivered

h 2−125,74 146.64 −125.74













eat deliv delivered ered vs Tem empera perature ture o wate w aterr delivered delivered

i+ure 8.2 Jraph eat delivered a+ainst te(perature of ,ater delivered













/*peri(ent 37 !roduction of vapour copression cycle on p#h dia+ra( and eber+y balances study %efri+eration lo, rate 1 T2 %efri+erant pressure 1 T2 %efri+erant pressure 6lo,91!8 %efri+erant pressure 6hi+h9 1!2 %efri+erant te(perature 1TT8 %efri+erant te(perature 1TT2 %efri+erant te(perature 1 TT3 %efri+erant te(perature 1 TT4 Coolin+ ,ater flo, rate 1T8 Coolin+ ,ater flo, rate 1T8 Coolin+ ,ater inlet te(perature1 TT5 Coolin+ ,ater outlet te(perature1 TT Co(pressor po,er input

Calculation7 'eter(ination enthalpy of refri+erant T, °C

h, enthalpy KJ/kg

20

2"8.3$

K ! >ars6abs 9 >ars6abs 9 !C C C C K ! C C M

).$ ).$ 2.) .& 2.3 "5.$ 3).2 23.) 4).) 2.) 2&.& 38.5 85$















Calculation at point 3 and 4 6%efer to Table Table A#88 in Appendi*97 Appendi*97 T, °C

h, enthalpy KJ/kg

30

2."8

30.2

hTT3

32

2"."

hTT3

G

2.$)P?H;+

T, °C

h, enthalpy KJ/kg

22

$2.84

23

h













G).))$4 ;+Hs /in

G

/out

ṁhTT3

G

0 Q ṁhTT4

0

G

ṁ6hTT3 #

G

).))$4;+Hs 62.$)#$3.59P?H;+

G

8.54 PM

hTT49

/ner+y >alance on the Co(pressor /in

G

/out













/*peri(ent 47 /sti(ation of the effect of the co(pressor pressure ratio on volu(etric %efri+erant flo, rate 1 T2 %efri+erant flo, rate 1 T2 %efri+erant !ressure 6lo,91 !8 %efri+erant !ressure 6hi+h91 !2 %efri+erant Te(perature1 Te(perature1 TT8

8. Co(pressor %atio C!%

G

%efri+erant pressure hi+h

K ! >ar6abs9 >ar6abs9 !C

).$ ).$ 2.) .& 2".3













ass flo, rate G

0.76608 LPMx

1000 c m 1 L

3

3

x

1m

3

( 100 cm )

x

1 min 60 s

G 5.43*8)#5 ;+Hs Actual volu(e flo, rate G

(ass flo, rate 'ensity of refri+erant 834#a

G5.43*8) #5;+Hs

4.25 ;+H(3 G

8.2"$*8) #5(3Hs

@olu(etric efficiency G

Actualvolu(etric flo,rate Theoretical volu(e of co(pressor

x 4.25

kg 3 m













CO! Test Test 8

).8"

).$&

'eter(ination enthalpy 8 of refri+erant T, °C

h, enthalpy KJ/kg

20

2"8.3$

27.3

hTT8

30

2"&.&"

'eter(ination enthalpy 2 of refri+erant

hTT8

G

2"".5 P?H;+















G

).)82$;+Hs 62"&.$)#2"".59P?H;+

G

).)2"5 ;?Hs

CO!G 0HM G 2".5H8)

G).8"













60.7

G

100

x 1.26 LPM

G)."5! )."5 

8 (3

8))) ;+

8 (in

(in

8))) 

(3

) s

Convert

G

























co(pressed fro( ).2) !a at 2.3C to ).&pa at "5.$ C and the enthalpy calculated is 2"."& ;?H;+ and 384.3" ;?H;+ respectively. The The refri+erant then enter the condenser at te(perature of 3).2C at ).&!a and leave the condenser at te(perature at 23.)C at ).&!a. The pressure is constant because the condenser under+oes the heat rejection process at constant pressure. The enthalpy calculated at 3).2C and 23.)C is 2.$) ;jH;+ and $3.5;?H;+ respectively. The enthalpy ,ere decreasin+ because at the condenser the heat ener+y ,as released to surroundin+ caused the heat ener+y in the refri+erant to drop.



















































Refrieration Unit Lab Report

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