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JOURNAL OF INFORMATION, KNOWLEDGE AND RESEARCH IN

MECHANICALENGINEERING

OPTIMIZATION OF NATURAL REFRIGERANTS

CARBON DIOXIDE (R744) AND AMMONIA (R717) IN

CASCADE REFRIGERATION SYSTEM USING

GENETIC ALGORITHM1PRASHANT VYAS, 2SATYASHREE GHODKE, 3ARUN WAMANKAR

1 MT!"# $%&'!%, D!*+%!% -. M!"#*/"*0 E/!!+/, T!"#-"+*%$ I$%/%&%! -.

T!"#-0-2, B#-*03 A$$-"/*%! P+-.!$$-+, D!*+%!% -. M!"#*/"*0 E/!!+/, T!"#-"+*%$ I$%/%&%! -.

T!"#-0-2, B#-*035 A$$/$%*% P+-.!$$-+, D!*+%!% -. M!"#*/"*0 E/!!+/, T!"#-"+*%$ I$%/%&%! -.

T!"#-0-2, B#-*03

vyasprashantdyah!!"#!"$n, %h!d&'"satyashr''yah!!"#!(, ar)n"*a(an&ar%(a$+"#!(

ASTRA-T : Selections of refrigerants is of vital importance in refrigeration & thus the present work deals

with optimization of cascade refrigeration system using eco friendly & natural refrigerants pair

Ammonia(R717 in high temperature side and !ar"on #io$ide (R7%% in low temperature applications 'hese

refrigerants have zero ozone depletion potential and less than 1 )* +ptimization of !ar"on #io$ide (R7%%

& Ammonia (R717 cascade refrigeration system performance parameters such as refrigeration effect,

coefficient of performance and e$ergetic efficiency was carried out using enetic Algorithm tool

KEY WORDS- -as#ad' R'.r$%'rat$!n Syst'(, G'n't$# A+%!r$th(, R/001R//

13 INTRODUCTION 6 W#2 CONH5 8

Before 1930 the refrigerants that were commonly in

use were Ammonia, Carbon Dioxide, Sulhur

Dioxide, !hane " roane# During 1930s $Safety%efrigerants& were introduced rimarilyChloroflurocarbons 'C(Cs) such as %11, %1* " %13

and +ydrochloroflurocarbons '+C(Cs) such as %**and %0* which relaced all refrigerants# -hen the

disastrous effect of C(Cs " +C(Cs on o.one layerwas disco/ered during 190s leading to hase out of

C(Cs by 1990 and +C(Cs by *000#

+ydroflurocarbon '+(Cs) do not directly damageo.one layer but they are Synthetic greenhouse gases

'S22s) with 2lobal warming otential# -hese

refrigerants ha/e been hased out in de/eloedcountries as er ontreal 4rotocol from 5nited

6ations !n/ironment 4rogramme '56!4) 71,*8#any industrial alications reuiring simultaneous

heating and cooling and cascade systems aear to bethe best alternati/e# A suitable selection of

refrigerants used in +- and :- cycles can ro/ide alarge temerature difference and good system

efficiency# Single stage and multi stage refrigerationsystems fail to widen the ga between heat source

and heat sin; temeratures reuired in odestresearch has been done in cascade systems based on

natural refrigerants thereby offering good otentialfor research#

Ammonia can be used in high temerature stage andcarbon dioxide can be used in low temerature stage

in two stage cascade refrigeration, for which the

lowest refrigeration temerature is limited abo/e ) wasreorted to be used as a cascade refrigerant for

achie/ing temeratures around

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reresentation and measures the uality of thereresented solution# -he fitness function is always

roblem deendent# (or instance, in the ;nasac;roblem one wants to maximi.e the total /alue of

obGects that can be ut in a ;nasac; of some fixedcaacity# A reresentation of a solution might be an

array of bits, where each bit reresents a differentobGect, and the /alue of the bit '0 or 1) reresents

whether or not the obGect is in the ;nasac;# 6ote/ery such reresentation is /alid, as the si.e of

obGects may exceed the caacity of the ;nasac;# -he

fitness of the solution is the sum of /alues of all

obGects in the ;nasac; if the reresentation is /alid,

or 0 otherwise# n some roblems, it is hard or e/enimossible to define the fitness exressionH in these

cases, interacti/e genetic algorithms are used#

>nce we ha/e the genetic reresentation and thefitness function defined, 2A roceeds to initiali.e a

oulation of solutions randomly, then imro/e it

through reetiti/e alication of mutation, crosso/er,in/ersion and selection oerators#I/%/*0/@*%/-

nitially many indi/idual solutions are randomlygenerated to form an initial oulation# -he

oulation si.e deends on the nature of the roblem,but tyically contains se/eral hundreds or thousands

of ossible solutions#-raditionally, the oulation is generated randomly,

co/ering the entire range of ossible solutions 'thesearch space)# >ccasionally, the solutions may be

IseededI in areas where otimal solutions are li;elyto be found#

S!0!"%/-During each successi/e generation, a roortion ofthe existing oulation is selected to breed a new

generation# ndi/idual solutions are selected through

a fitness."ased rocess, where fitter solutions 'asmeasured by a fitness function) are tyically more

li;ely to be selected# Certain selection methods ratethe fitness of each solution and referentially select

the best solutions# >ther methods rate only a randomsamle of the oulation, as this rocess may be /ery

time

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Start

(itness (unction

!stimating ranges for /ariables

nitial 4oulation

!/aluation J (itness Crosso/er and mutation

Comuting

Selection of arents

-ermination 6o

Criterion M

yes

Choose the bestndi/idual

Sto

(ig#3 (low chart of 2enetic Algorithm

A Ranges of the /aria"les!ight /arious temeratures of +- and :- cycles ha/ebeen considered as indeendent /ariables with

redefined range as shown in the table( !2+-FA%AB:!S

!ight /ariables 'C) -emerature%ange '=C)

:o

wer

+igher

:ow side e/aorator temerature, A

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0 10 20 30 40 50 60 70 80 90 100-650

-600

-550

-500

Generation

Fitnessvalue

Best: -604.3216 Mean: -603.7781

1 2 3 4 5 6 7 8-40

-20

0

20

40

Number of variables (8)

Currentbestindividual

Current Best Individual

Best fitness

Mean fitness

(ig# Best (itness 4lot for %!1 of the Cascade

System

(ig# shows the best fitness /alue lot searched by2enetic Algorithm for the %!1 of the cascade

refrigeration system#" Opt$($at$!n !. th' -OP !. th' -as#ad' Syst'(

3 G-!+/ !&*%/- .-+ COP

!+*85%1644885(A.44%%9(.44%31(!

6444%2(#644138(0644848(;.44443(

.44447(%

C>4A B C D E F G H COP

59 9 93994 3

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searched by 2A tool# According to thesecombinations, /alue of %!1 is maximum if system

oerate with -!: P D4 >.one deletion otential= REFERENCES

718 ontreal 4rotocol on substances that delete the

o.one layer# 5nited 6ations !n/ironment rogramme'56!4), 19@#7*8 56!4 Assessment reort of the technology and

economic assessment anel, 56!4 >.oneSecretariat, 6airobi, Renya

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Rhurana, %#R#, Sar;ar, #, *00# >timi.ation of aC>*.a, 4#%#-ailor,

-hermodynamic analysis and otimi.ation of

%0A

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