components compression refrigerator
TRANSCRIPT
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7/25/2019 Components Compression Refrigerator
1/20
K.
U.Leuven
TME
Evaporator and condenser
Tube in tube condenser
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7/25/2019 Components Compression Refrigerator
2/20
K.
U.Leuven
TME
Evaporator and condenser
Shell and tube evaporator
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7/25/2019 Components Compression Refrigerator
3/20
K.
U.Leuven
TME
Evaporator and condenser
Bare-tube coil evaporator
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7/25/2019 Components Compression Refrigerator
4/20
K.
U.Leuven
TME
Evaporator and condenser
Plate-surface evaporator
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7/25/2019 Components Compression Refrigerator
5/20
K.
U.Leuven
TME
Evaporator and condenser
Dr e!pansion evaporator
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7/25/2019 Components Compression Refrigerator
6/20
K.
U.Leuven
TME
Evaporator and condenser
"looded evaporator
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7/25/2019 Components Compression Refrigerator
7/20K.
U.Leuven
TME
CompressorPerfor#ance curves
L
$e
L%$e
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7/25/2019 Components Compression Refrigerator
8/20K.
U.Leuven
TME
CompressorPerfor#ance curves
L
$e
L%$e
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7/25/2019 Components Compression Refrigerator
9/20K.
U.Leuven
TME
Throttling valve
Capillary tube
Si#plest confi&uration
'er li#ited control
capabilit L( D( p#ass flo) rate
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7/25/2019 Components Compression Refrigerator
10/20
K.
U.Leuven
TME
Throttling valve
Hand expansion valve
Manuall controlled needle
valve
Pin shaped valve plu&
Li#ted control freedo#
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7/25/2019 Components Compression Refrigerator
11/20
K.
U.Leuven
TME
Throttling valve
Automatic expansion valve
*onstant evaporator
pressure e!pansion valve
Balance bet)eenevaporator pressure and
sprin& pressure is
#aintained
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7/25/2019 Components Compression Refrigerator
12/20
K.
U.Leuven
TME
Throttling valve
Automatic expansion valve
+i&h ther#al load, non
efficient use of heat
e!chan&er surface
Lo) ther#al loads, dan&er
for liuid enterin& the
co#pressor
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7/25/2019 Components Compression Refrigerator
13/20
K.U.Leuven
TME
Throttling valveThermostatic expansion valve
Most )idel used
Maintains a constant a#ount of superheat at the evaporator.s
outlet
"ull and effective use of the evaporator surface
Te#perature sensin& bulb located at the outlet of the evaporator/ *har&ed )ith refri&erant 0in 1-phase state2
/ Measures the te#perature of the vapour leavin& the evaporator
/ *onverts this te#perature to related pressure
/ 3ppl this pressure to diaphra in e!pansion valve
/ 4n the other side of diaphra, evaporator 0inlet2 pressure 5 sprin& pressure *han&es in pressure are used to position valve needle
/ 6f #ore superheatvlave opens #ore 0throttlin& valve controls superheat2
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7/25/2019 Components Compression Refrigerator
14/20
K.U.Leuven
TME
Throttling valve
Thermostatic expansion valve
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7/25/2019 Components Compression Refrigerator
15/20
K.U.Leuven
TME
Throttling valve
Thermostatic expansion valve
Disadvanta&e,
6f hi&h flo) rates( then si&nificant pressure drop due to friction
Then lo)er pressure at outlet evaporator
Then lar&er superheat at outlet evaporator
Then portion of evaporator.s surface beco#es ineffective for
absorbin& the refri&erant.s latent heat
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7/25/2019 Components Compression Refrigerator
16/20
K.U.Leuven
TME
Throttling valve
Externally equalized thermostatic expansion valve
Pressure at the evaporator outlet is trans#itted to the side of
the diaphra that the setpoint ad7ustin& sprin& acts upon
effect of p is neutrali8ed )ithout reducin& the effective
heat transfer surface
psensin& bulb
poutlet evaporatorpsprin&
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7/25/2019 Components Compression Refrigerator
17/20
K.U.Leuven
TME
Throttling valve
Externally equalized thermostatic expansion valve
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7/25/2019 Components Compression Refrigerator
18/20
K.U.Leuven
TME
Secondary system components
Lubricant separator: separates oil fro# the dischar&evapours and safel returns it to the co#pressor 0presence of oil in
condenser%evaporator ha#pers the heat transfer2
Refrierant drier: contains a che#ical desiccant that adsorbs#oisture preventive action a&ainst corrosion or acid for#ation
throttlin& valve #a be bloc9ed b fro8en #oisture
Receiver tan! valve: to avoid liuid in the co#pressor aftera restart: )hen valve closed no liuid to)ards evaporator
evaporator pressure decreases lo) pressure re&ulator active
co#pressor off )hen restartin& the co#pressor no liuid in
the suction line
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7/25/2019 Components Compression Refrigerator
19/20
K.U.Leuven
TME
Hot as defrost line: connects the dischar&e line to theevaporator to #elt the ice and frost fro# the evaporator surface
0)hen T ; de) point #oisture in air condenses: if T ; free8in&
pointfrost( )hich for#s an insulation on the heat e!chan&er
surface
$edecreases
*4P
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7/25/2019 Components Compression Refrigerator
20/20
K.U.Leuven
TME
'alves * and B open
'alves 3 and D closedHeat pump
'alves 3 and D open
'alves * and B closed
Refrierator
condenser
evaporator