components compression refrigerator

7/25/2019 Components Compression Refrigerator

1/20

K.

U.Leuven

TME

Evaporator and condenser

Tube in tube condenser


2/20

K.

U.Leuven

TME


Shell and tube evaporator


3/20

K.

U.Leuven

TME


Bare-tube coil evaporator


4/20

K.

U.Leuven

TME


Plate-surface evaporator


5/20

K.

U.Leuven

TME


Dr e!pansion evaporator


6/20

K.

U.Leuven

TME


"looded evaporator


7/20K.

U.Leuven

TME

CompressorPerfor#ance curves

L

$e

L%$e


8/20K.

U.Leuven

TME

CompressorPerfor#ance curves

L

$e

L%$e


9/20K.

U.Leuven

TME

Throttling valve

Capillary tube

Si#plest confi&uration

'er li#ited control

capabilit L( D( p#ass flo) rate


10/20

K.

U.Leuven

TME

Throttling valve

Hand expansion valve

Manuall controlled needle

valve

Pin shaped valve plu&

Li#ted control freedo#


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


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


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


14/20

K.U.Leuven

TME

Throttling valve

Thermostatic expansion valve


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


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&


17/20

K.U.Leuven

TME

Throttling valve

Externally equalized thermostatic expansion valve


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


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


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

components compression refrigerator

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