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Refrigeration System
an overview
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Refrigeration System
Refrigeration system is a combination of machineries.
These machineries perform several processes.
All the processes complete a Refrigeration Cycle to-
Remove heat from low temperature region
Transfer heat to high temperature region
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UNEP 2006UNEP 2006
Introduction
Type of refrigeration
Assessment of refrigeration and AC
Energy efficiency opportunities
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Refrigerators and Heat Pumps
Refrigerators: Tae !eat from cooler place
Transfer heat to hotter place
"b#ective : $eeping low temp. at the cooler place %se& in Tropical Countries'(eserts for Space Cooling
!eat )umps: Tae !eat from cooler place Transfer heat to hotter place
"b#ective : $eeping high temp. at the hotter place
%se& in Col& Countries for space heating
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IntroductionIntroduction
How does
it work?High Temperature Reservoir
Low Temperature Reservoir
R Work Input
Heat Asored
Heat Re!ected
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IntroductionIntroduction
Therma" energy moves from "eft to right through five
"oops of heat transfer#
How does it work?
(Bureau of Energy Efficiency, 2004)
$%Indoor air
"oop
&%
Chi""ed
water "oop
'%
Refrigerant
"oop
(%
Condenser
water "oop
)%
Coo"ing
water "oop
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IntroductionIntroduction
AC options * cominations#
AC +ystems
Air Conditioning ,for comfort * machine%
+p"it air conditioners
-an coi" units in a "arger system
Air hand"ing units in a "arger system
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IntroductionIntroduction
2ank of units off5site with common
Chi""ed water pumps
Condenser water pumps
Coo"ing towers
6ore "eve"s of refrigeration*AC3 e7g7
Comfort air conditioning ,&/5&) oC%
Chi""ed water system ,8 1 $/ oC%
2rine system ,9 / oC%
Refrigeration at "arge companies
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Training Agenda# Refrigeration :Training Agenda# Refrigeration :
Air ConditioningAir Conditioning
Introduction
Type of refrigeration
Assessment of refrigeration and AC
Energy efficiency opportunities
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Types of RefrigerationTypes of Refrigeration
;apour CompressionRefrigeration ,;CR%# uses
mechanica" energy
;apour Asorption Refrigeration
,;AR%# uses therma" energy
Refrigeration systems
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Types of Refrigeration Cycle
There are two types of refrigeration cycle:
*apor Compression Cycle
+
*apor Absorption Cycle
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Type of RefrigerationType of Refrigeration
;apour Compression Refrigeration
High"y compressed f"uids tend to get
co"der when a""owed to e.pand
If pressure high enough
Compressed air hotter than source
of coo"ing
E.panded gas coo"er than desired
co"d temperature
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Type of RefrigerationType of Refrigeration
;apour Compression Refrigeration
Refrigeration cyc"e
Condenser
Evaporator
High
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Type of RefrigerationType of Refrigeration
;apour Compression Refrigeration
Refrigeration cyc"e
Low pressure "i>uid refrigerant inevaporator asors heat and
changes to a gas
Condenser
Evaporator
High
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Type of RefrigerationType of Refrigeration
;apour Compression Refrigeration
Refrigeration cyc"e
The high pressure superheated
gas is coo"ed in severa" stages inthe condenser
Condenser
Evaporator
High
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Type of RefrigerationType of Refrigeration
;apour Compression Refrigeration
Refrigeration cyc"e
Li>uid passes through e.pansion device3
which reduces its pressure and contro"s thef"ow into the evaporator
Condenser
Evaporator
High
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Type of RefrigerationType of Refrigeration
;apour Compression Refrigeration
Type of refrigerant
Refrigerant determined y the
re>uired coo"ing temperature
Ch"orinated f"uorocarons ,C-Cs% or
freons# R5$$3 R5$&3 R5&$3 R5&& and R5)/&
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Type of RefrigerationType of Refrigeration
;apour Compression Refrigeration
Choice of compressor3 design of
condenser3 evaporator determined y Refrigerant
Re>uired coo"ing
Load Ease of maintenance
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Type of RefrigerationType of Refrigeration
;apour Asorption Refrigeration
Condenser enerator
Evaporator
AsorerCo"d
+ide
Hot
+ide
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UNEP 2006UNEP 2006
Type of RefrigerationType of Refrigeration
;apour Asorption RefrigerationElectrical
Equipe
nt!
"efr
igera
tion#
$%
Evaporator
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Type of RefrigerationType of Refrigeration
;apour Asorption Refrigeration
High pressure generator
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UNEP 2006UNEP 2006
Type of RefrigerationType of Refrigeration
Evaporative Coo"ingElectrical
Equipe
nt!
"efr
igera
tion#
$%
($&apte& fro
'unter, 200)
Co"d
AirHot Air
+prink"ing
Water
Air in contact with water to coo" it c"ose to @wet
u" temperature
Advantage# efficient coo"ing at "ow cost
=isadvantage# air is rich in moisture
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UNEP 2006UNEP 2006
Training Agenda# Refrigeration :Training Agenda# Refrigeration :
Air ConditioningAir Conditioning
Introduction
Type of refrigeration
Assessment of refrigeration and AC
Energy efficiency opportunities
Electr
ical
Equipe
nt!
"efr
igera
tion#
$%
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Assessment of Refrigeration and ACAssessment of Refrigeration and AC
Coo"ing effect# Tons of Refrigeration
TR is assessed as#
Assessment of Refrigeration
$ TR B '/&( kCa"*hr heat re!ected
TR B .
Cp .
,Ti 1 To% * '/&(
* + a flo rate of coolant in -g!.r
%p + i coolant pecific .eat in -%al !-g &eg %
/i + inlet, teperature of coolant to eaporator (c.iller) in 0%
/o + outlet teperature of coolant fro eaporator (c.iller) in 0%
UNEP 2006UNEP 2006
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Vapour Absorption Refrigeration System
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(ifference of *C an& *A Cycle
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Refrigerants
Refrigerants are chemicals that act as the working fluid inRefrigeration cycles
The names of the Refrigerants were initially &evelope& bya company name& (u)ont for *CRS-
R (Carbon atoms-1) (Hydrogen atoms+1) (Flourine atoms)
R-11 = R011 = CCl3F an& R-22= R022 = CHF2Cl
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Refrigerant'Absorber Combination for *ARS
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(esirable )roperties of Refrigerant
,ow "one (epletion )otential
,ow lobal /arming )otential
!igh hfg: Can tae more heat before vaporiing
,ow Specific volume0m1'g2 : easier to compress
Chemically stable3 non-to4ic an& non corrosive
,ow cost an& easy availability
(oes not eep very low pressure in evaporator 0air leaage2
(oes not eep very high pressure in con&enser 0refrigerant leaage2
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Type of RefrigerationType of Refrigeration
;apour Compression Refrigeration
Two advantages
Lot of heat can e removed ,"ot of
therma" energy to change "i>uid to
vapour%
Heat transfer rate remains high,temperature of working f"uid much
"ower than what is eing coo"ed%
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