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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%