Deepak Gangwar

8/18/2019 Deepak Gangwar

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APROJECT REPORT

ON“HYDRULLIC ROBOTIC ARM”

“Submitted in partial fulfillment of the requirement for the award of degree” of

BACHELOR OF TECHNOLOGYin

MECHANICAL ENGINEERINGDr.A.P.J ABDUL KALAM TECHNICAL UNIVERSITY

LUCKNO!

Submitted by: -DESHDEEPAK MISHRA "#$%&'%(($')FIRDOUS BI "#$%&'%(($*)SAURAV SINGH "#$%&'%((*#)VIKAS KUMAR PANDAY "#$%&'%(##+)

Guided by: -

Mr. ATIF ALI KHANASST. PROFESSOR

DEPARTMENT OF MECHANICAL ENGINEERINGFUTURE INSTITUTE OF ENGINEERING , TECHNOLOGY BAREILLY

"U.P.)$(#- #'


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FORE!ORDING LETTER

Forwarding here with is the Project report entitled

“HYDRULLIC ROBOTIC ARM” submitted by DESHDEEPAK

MISHRA VIKAS KUMAR PANDAY SAURAV SINGH FIRDOS BI

students of this institution.

The Project report is in the partial ful llment of requirements

towards the award of the degree of Bachelor of Technology in

MECHANICAL ENGINEERING (Dr. A.P.J ABDUL KALAMTECHNICAL UNIVERSITY, LUCKNOW).

It has been carried out under the guidance and super ision

of !r. "umit #umar $%sst. Professor& 'epartment of !echanical

(ngineering) F.I.(.T. Bareilly.

Forwarded by: - Approvedby:-

!r. %TIF %*I #+%, !r. #.P."-hauhan

$%sst. Professor& $+. .'&


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'ept. of !echanical (ngg. 'ept. of !echanical (ngg

F.I.(.T Bareilly F.I.(.T Bareilly

CERTIFICATE

It is certi ed that DESHDEEPAK MISHRA VIKAS PANDAY SAURAVSINGH FIRDOUS BI student of B.T(-+ $ nal year&) 'epartment of !echanical (ngineering has carried out the project wor/)presented in this entitled “HYDRULLIC ROBOTIC ARM” foe theaward of partial ful llment of the requirement toward theBachelor of Technology in MECHANICAL ENGINEERING fr !Dr.A.P.J ABDUL KALAM TECHNICAL UNVERSITY, LUCKNOWunder my super ision during academic year 012340125.

!r. %tif %li #han !r.PrashantPratap !all $Project guide& $Projectincharge&


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ACKNO!LEDGEMENT

%fter completing our project “ HYDRULLIC ROBOTIC ARM” )

we wish to e6press my obligations to the college sta8. 9e wish toe6press our obligations to our fellow project mar/ers.9e would li/e to than/ and pay our obligations to Mr. K.P.S

CHAUHAN (H.O.D"#M$%&' %'* E + $$r +) for his guidanceregarding the project.9e would li/e to pay our special gratitude to:4

!r. P;%"+%,T P;%T%P !%**$%sst. Professor&!r. P;%B+%T #


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,%!( 7 SAURAV SINGH;oll no 7 20>?5>11@2

,%!( 7 VIKAS PANDAY

;oll no 7 20>?5>122A

ABSTRACT

We have designed this project as a major innovation in the field of air conditioning . Our project “COMPRESSORLESS REFRIDGERATOR SYSTEM ” is a perfect combination of electronic and mechanical sciences or wecan call it mechatronics.

Team 12 designed and constructed a thermoelectric cooler with an interior coolingvolume of 0.01 cubic meters !2"cm # 2"cm # 2"cm$. The thermo electric cooler was e%uipped with on&off control which was found to be ade%uate to meet the

re%uired precision of '&( 0.2 degrees )elsius put forth in the project re%uirements.One liter of water was placed inside the cooler to test the performance of the

device. We tested the ma#imum performance of the device by cooling a sampledown to " degrees )elsius. Temperature control was also tested by cooling one liter of water from room temperature down to 10 degrees )elsius. On&off control wasfound to give ade%uate performance and we met or e#ceeded all of our projectre%uirements set forth in the fall semester.

We designed our project by using *eltier chip and electronic power supplycircuit.+eart of the project i/ this strong powerful *eltier chip it has a high coolingand heating capacity at 12v.dc and 220v ac *ower supply.

Writing a report on technical aspect is indeed a very challenging task. Thestudent has to possess not only e#pertise in the subject matter but also thetechni%ue of selecting appropriate material from the vast fund of knowledge theyhave regarding the subject of project and present it in a way which the readers can


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easily understand. ,udging from the remarks of the e#perts who reviewed thereport and also on the basis of earlier projects by these students in the -echanicalfield. have no doubt in my mind that they had done an e#cellent job.

The institute will/ therefore fell amply rewarded if the other students and

teachers may go through this report for enlarging their knowhow of theCOMPRESSORLESS REFRIDGERATOR SYSTEM .

ny suggestions for the improvement of this project and the report from all%uarters will be most welcome.

TABLE OF CONTENT

PARTICULARS0 PAGE NO.

CHAPTER # , I -r /%-

bjecti e

Thermo electric e8ectThermo electric ;efrigeration

CHAPTER #0, A1 /- Pr 2$%-

3 Peltier e8ect

CHAPTER #4, C&'r'%-$r 5- %5

Thermo power

-harge carrier di8usion


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Phonon drag

"pin seebac/ ehhect and magnetic batteries

CHAPTER #6, Pr % 7*$ f Pr 2$%-

3 "eebac/ e8ect

3 Thermoelectric cooling

CHAPTER #8, A '*95 5 f 7r 2$%-

3 Thomson e8ect

3 The Thomson relationships3 Figure of merit

3 'e ice eCciency

3 Performance3 !aterials used to built thermocouples

CHAPTER #:, D$-' *5 f 7r 2$%-

Bloc/ diagram

-omponent detail

Peltier de ice with heat sin/

"olar plate

"ilicon"ilicon in solar cells

,4 type plus P4 type silicon

%pplication


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CHAPTER #;, C !7 $ - /5$

CHAPTER #;, P


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3igure 4o *age 4o 3igure 4o *age 4o1 12 252 5 16 276 7 18 61

8 9 1" 62" 12 1 6516 15 69

5 18 17 807 15 19 819 22 20 82

10 26 21 8611 2 22 88

LIST OF TABLES

Table 4o *age 4o Table 4o *age 4o 1 8" 6 87 2 85 8 87


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Chapter-1 Introduction

Objective The main objective of the project is to build a refrigerator which works solely on

the solar energy. This project also eliminates the use of compressors in refrigeratorswhich by their noise and energy usage/ makes refrigerator a disturbance. We arealso avoiding conversion of solar energy in to electricity thus the efficiency can beincreased compared to conventional solar refrigerator .

T12r3o24256ri5 Eff256

: Thermoelectric effect/ is the direct conversion of thermal differentials toelectric voltage and vice versa. ;elated effects are the Thomson effect and,oule heating.

: The *eltier ,oule heating cannot bereversible under the laws of thermodynamics .

Temperature controlled environments are crucial in biomedical research

laboratories and medical institutes. =toring/ preparing/ analy?ing samples/ or

culturing bacteria needs precisely controlled temperature environments. )urrently/most commercial products are li%uid baths. This re%uires the sample to be enclosed

in a watertight test tube or petry dish in order to perform the e#periment.

Team 12 took on the challenge of designing such a device using an air bath. This

eliminates the need for the e#perimental specimen to be placed in a well sealed

container before the e#periment can commence. s laboratory e%uipment/ the

device must be easy to use/ aesthetically pleasing/ and control the temperature

precisely and accurately. The final device also has to be free of vibrations to avoid

disturbing any samples which may be put in the temperature controlled

environment.

!1$


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Thermo @lectric -odules !T@-s$ are effectively heat pumps that transfer heat

from one side of the module to the other when a current is applied. This

phenomenon is called the *eltier effect. The goal of this project is to utili?e this

phenomenon to build a temperature controlled environment free of vibration andmeet all the project re%uirements.

@nvironmental and economic impacts of global electricity generation systems inthe world considering the need for alternative energy sources emerge. )oal/ oil/natural gas/ A*B/ wood/ all the fossil fuels such as biogas and hydro/ wind/ waveenergies/ all energy sources used for energy supply/ such as limited.

4uclear energy/ manufacturing and recycling of energy is the type who wants thevery great attention. fter removal of substances used as fuel in nuclear reactorscontinue to spread radiation to the environment over hundreds of years in placeswhere they are stored. Who is the radiation emitted from the storage areas whenthe environment is not known to affect how and how much .Thermoelectric generators !*eltier$ are the temperature differences between thetwo surfaces are elements that produce direct current.=ome studies on the T@ generator is as followsC

n a study of electrical energy into heat energy directly and made a system thatcharges the battery. microcontrollers to track the ma#imum power point and 5.99

W of power was obtained. T@ element used 112507Ddir T@). This module is testedfor different temperature and resistance E1F.

n a study of a T@ generator of electrical energy has been placed in the surface of the stove. +ot stove as the source/ the room air temperature is used as a coldsource/ were obtained from the power of about 8 W Dage E2F.

n one study/ T@ generator utili?ing solar energy to generate electricity and makingit theoretically hesaplanmGHtGr.60 northern latitude cooling electric T@ all year for

the region and a number of different elements for T@ cooling power was calculatedE6F. n a study of renewable energy sources/ geothermal energy directly toelectrical energy into the microcontroller controlled thermoelectric generator andthe system has been tested E8F. n a study of thermoelectric generators of electricity

production is made by concentrating the sunDs energy.!2$


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E"F n this study/ thermoelectric !T@$ !*eltier$ modules with the help of electricalenergy into heat energy from the thermoelectric generator application was made.-odules connected in series/ known as very low yields of the heat e#changer has

been reached between the voltages that are re%uired for use with the placement.

@asy to clean and can be obtained by increasing the number of modules used ingeothermal energy can be converted to electrical energy is everywhere.Thermoelectric modules !*eltier$ One surface of the *(type semiconductor material/ the other surface of the 4(type semiconductor material/ a semiconductor system. @lectrically connected in series/ parallel depends on the heat. nternals areas shown in the figure. Ipper and lower surface of the module in 3igure 1 asshown in. @lectrically conductive ceramic thermal insulation used on surfaces to be

preferred. Jespite the low cooling heating efficiency of the T@ module provides

the opportunity for %uiet operation is preferred in many applications. 3or e#ample/the recent widespread use of vehicle type refrigerators and )*I coolers for T@common e#amples. E $

!HAT IS THERMOELECTRIC REFRIGERATION7

;efrigeration is the process of pumping heat energy out of an insulated chamber inorder to reduce the temperature of the chamber below that of the surrounding air.Thermoelectric refrigeration uses a principle called the K*@AT @;K effect to pump

heat electronically. The *eltier effect is named after a 3rench scientist whodiscovered it in 1768.

HO! DOES IT !ORK7

n 1768 ,ean *eltier noted that when an electrical current is applied across the junction of two dissimilar metals/ heat is removed from one of the metals and

transferred to the other. This is the basis of thermoelectric refrigeration.Thermoelectric modules are constructed from a series of tiny metal cubes of dissimilar e#otic metals which are physically bonded together and connectedelectrically.

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When electrical current passes through the cube junctions/ heat is transferred fromone metal to the other. =olid state thermoelectric modules are capable of transferring large %uantities of heat when connected to a heat absorbing device onone side and a heat dissipating device on the other.

The LoolatronDs internal aluminium cold plate fins absorb heat from the contents/!food and beverages$/ and the thermoelectric modules transfer it to heat dissipatingfins under the control panel. +ere/ a small fan helps to disperse the heat into the air.The system is totally environmentally friendly and contains no ha?ardous gases/nor pipes nor coils and no compressor. The only moving

part is the small 12volt fan. Thermoelectric modules are too e#pensive for normaldomestic and commercial applications which run only on regular householdcurrent. They are ideally suited to recreational applications because they are

lightweight/ compact/ insensitive to motion or tilting/ have no moving parts/ andcan operate directly from 12volt batteries.

!HY IS IT BETTER THAN AN ICE CHEST7

3ood and beverages are kept cold and dry. 4o space is wasted for ice !unless of course you want ice/ in which case we can help to preserve it 6 or 8 times longer than a plain cooler$. This system consists of @mbedded devices/ =olar panel/ )harger/ Mattery/ Jisplay/

nalog to Jigital )onverter ! J)$/ Temperature sensor/ Jriver/ *eltier -odule/Temperature controlled chamber and Leypad. The solar panel is applied to convertthe heat energy into electrical energy and it is fed to the charger/ which is checked

by the implanted system and the output of the charger is given to Mattery to storethe electric potential. gain the Mattery voltage is given to the J)/ the J) isused to measure the Mattery voltage and converts it into a digital signal and given

back to embedded system. When the level of the voltage decreased below athreshold value !N11 $/ the charger is activated and solar voltage is given to a

battery for storage. The temperature sensor is used to measure the temperature of the chamber and the output of the temperature sensor is given to J)/ where J)converts analog signal to digital signal and given to @mbedded system. The@mbedded system is programmed like that when it receives the signal from thekeypad it checks the temperature of the chamber and activates the Jriver.

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The driver is used to run the *eltier module. *eltier is a -odule which generatesavoltage when there is a differenttemperature on each side. )onversely/ when avoltage is applied to it/ it creates a temperature difference. t the atomic scale/ anapplied temperature gradient causes charge carriers in the material to diffuse from

the hot side to the cold side. =o the *eltier module can cool and heat the chamber. The keypad is used to set the temperature value to the chamber and at the sametime the display used in this system to show the process carried out in the system.The following 3igure 1 shows the overall system block diagram of the solar refrigerator for vaccine.

Overall =ystem Mlock Jiagram 3igure(1

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CHAPTER #0, A1 /- Pr 2$%-

PELTIER EFFECT

The thermoelectric refrigerator works on the *@AT @; effect that The *eltier<

=eebeck effect/ or thermoelectric effect/ is the direct conversion of thermal

differentials to electric voltage and vice versa. ;elated effects are the Thomson

effect and ,oule heating. The *eltier ,oule heating

cannot be reversible under the laws of thermodynamics.

3 B(2

! $


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n 1768/ a 3rench watchmaker and part time physicist/ ,ean *eltier found that

an electrical current would produce a temperature gradient at the junction of two

dissimilar meta

> + 4A $?&


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CHAPTER #4, C&'r'%-$r 5- %5

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A89:n528 R2fri;2r:6or Mo824 :n8 Co3


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E=ISTING SYSTEM

n recent years the price of thermoplastic materials is declining/ so the cost of semiconductor/ solar refrigeration production will decrease/ and its performance

has improved/ which greatly contribute to the promotion of the technology of solar semiconductor refrigeration. 4ow there are many mature technology methods for the use of solar energy for refrigeration. +owever/ no matter the absorption of solar energy/ or steam jet/ etc./ ll of them need to use fluoride/ lithium bromide andammonia refrigerants. n contrast/ semiconductor refrigeration has more obviousadvantages. t does not use refrigerants without environment pollution andcomplicated transmission pipeline. t can only cool a special device or a specificarea. The cooling bo# has small si?e and light weight/ and it can save the

construction area significantly. 4o mechanical rotation/ so the cooling bo# isreliable and the maintenance was easy without noise and wear. t can achieve thetwo different purposes of cooling and heating by changing the direction of current.The cooling was %uick and it can be controlled by regulating the work of power/ sothe control is very convenient. n this case/ the product was designed by combiningthe two advantages. The system includes solar cells/ controllers/ batteries/semiconductor refrigeration part/ and so on. =ince solar energy is not continuous/in order to ensure that the refrigerator can be worked continuously at night andcloudy days/ generally the system was e%uipped with a battery !battery is also

playing the role of the regulator in this system$ and it was also e%uipped with acontroller which has the function of protecting battery to avoid over charge andover discharge.

!10$


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CHAPTER #6, Pr % 7*$ f Pr 2$%-

S22>25? 2ff256

3ig("

: The =eebeck effect is the conversion of temperature differences directly into

electricity. This effect was first discovered/ accidentally/ by the Berman

physicist Thomas ,ohann =eebeck in 1721/ who found that a voltage e#isted

between two ends of a metal bar when a temperature difference PT e#isted

in the bar.

: The effect is that a voltage/ the thermoelectric @-3/ is created in the presence of a temperature difference between two different metals or

semiconductors. This causes a continuous current to flow in the conductors

!11$


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if they form a complete loop. The voltage created is of the order of several

microvolts per degree difference.

n 1721/ Thomas =eebeck found that an electric current would flow continuously

in a closed circuit made up of two dissimilar metals/ if the junctions of the metals

were maintained at two different temperatures.

3ig(

T12r3o 24256ri5 5oo4in;: Thermoelectric coolers are solid state heat pumps used in applications where

temperature stabili?ation/ temperature cycling/ or cooling below ambient are

re%uired.

: There are many products using thermoelectric coolers/ including ))J

cameras !charge coupled device$/ laser diodes/ microprocessors/ blood

analy?ers and portable picnic coolers.

: The typical thermoelectric module is manufactured using two thin ceramic

wafers with a series of * and 4 doped bismuth(telluride semiconductor

material sandwiched between them


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!12$

Fig4?

: The 4 type material has an e#cess of electrons/ while the * type material has

a deficit of electrons. One * and one 4 make up a couple/ as shown in 3igure

1. The thermoelectric couples are electrically in series and thermally in

parallel. thermoelectric module can contain one to several hundred

couples.


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$2A&

CHAPTER #8, A '*95 5 f 7r 2$%-

T& !5 E?$%-'isco ered by 9illiam Thomson $*ord #el in&

9hen an electric current Dows through a conductor) the ends

of which are maintained at di8erent temperatures) heat is

e ol ed at a rate appro6imately proportional to the product

of the current and the temperature gradient.

dxdT

I dx

dQτ =


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$2>&

T1o3/on R24:6ion/1i<


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!1"$

Fig4E


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!1 $

D2/i;nin; of 612r3:4 23f r2fri;2r:6ion

Th Q Tamb ' !O$ R!S h$ where

T+ QThe temperature of hot side

TambQThe ambient temperatureOQthermal resistance of heat e#ch

S hQheat realeased heat released to the hot side of the thermoelectric !watts$.

S h Q S c ' * in


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!15$

Where

S h Q the heat released to the hot side of the thermoelectric !watts$.

S c Q the heat absorbed from the cold side !watts$.

* in Q the electrical input power to the thermoelectric !watts$.

: The temperature difference across the thermoelectric !T$ relates to T h and T c

according to @%uation

: T Q T h < Tc

: The thermoelectric performance curves in 3igures 2 and 6 show the

relationship between T and the other parameters.

: @stimating S c/ the heat load in watts absorbed from the cold side is difficult/

because all thermal loads in the design must be considered. mong these

thermal loads areC

: ctiveC 2; heat load from the electronic devices

ny load generated by a chemical reaction

: *assive


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!17$

: ;adiation !heat loss between two close objects with different temperatures$.

: )onvection !heat loss through the air/ where the air has a differenttemperature than the object$

: nsulation Aosses

: )onduction Aosses !heat loss through leads/ screws/ etc.$

: Transient Aoad !time re%uired to change the temperature of an object$

: s the thermoelectric operates/ the current flowing through it has two

effectsC

: !1$ the *eltier @ffect !cooling$ and

: !2$ the ,oulian @ffect !heating$.

: We know that joulian effect is proportional to the s%uire of the current so

heating effect will dominates the cooling effect that why we can not increase

the current to a ma#imum value called ma# for themo(electric.

: The thermal resistance of the heat sink causes a temperature rise above

ambient. f the thermal resistance of the heat sink is unknown/ then estimates

of acceptable temperature rise above ambient areC

: 4atural )onvection20 ) to 80 )

: 3orced )onvection10 ) to 1" ): Ai%uid )ooling2 ) to " ) !rise above the li%uid coolant temperature$

: s we have done our design on a -elcor thermoelectric . The specifications

for the are !these specifications are at T h Q 2" )$C


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!19$

• S ma# Q "1.8 watts

: ma# Q 1".8 volts

: ma# Q .0 amps

: T ma# Q 5 )

to determine if this thermoelectric is appropriate for this application/ it must

be shown that the parameters T and Sc are within the boundaries of the

performance curves.

: Our main aim to maintain the temperature of container " ) which contain 1litres of air in 0."minute.

we know 1000litres Q1m 6

1 litresQ0.01 m 6

density of airQ1.296 kg&m 6.

mass of air Q0.01 R1.296Q0.020 77kg

specific heat of airQ1k,&Lg k

s SQmRsR!t h(tc$Q0.020 77R1000R!6"("$Q 20. 8 ,

this is maintain in 0."minutes so

;e%uired powerQ 20. 8&!0."R 0$Q22 watts

! s we assume that the ambient temperature T ambQ2"c the rise in the temperature

due to sink resistance is 10 )

=o final temperature will be Q2"'10Q6" )$


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!20$

*erformance )urve !T vs. S c$

3ig(9 *erformance )urve !T vs. oltage $


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!21$

3ig10


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!22$

: =o by the graph

ma#imum current Q 6. amp .

corresponding voltage by graph between temperature and voltage

voltageQ10v

4ow we will determine the corresponding value of temperature by these values of

current and voltage.

We know that the temperature at hot side

Th Q Tamb ' !O$ R!S h$

alue of heat released at hot side

S h Q S c ' * in

4ow *in that is the input power to produce this effect is

* inQ R

Q10volt

Q6. amp

*inQ10R6. Q6 watt

: nd S hQS c'* in

Q22'6


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!26$

Q"7 watts

nd ThQ Tc ';conRSh

4ow the temperature is also rise due to its convective resistance / we assume that

the convective resistance of the sink is 0.1" )

=o ThQ2"'0.1"R"7Q66.5 )

The calculated Th is close enough to the original estimate of Th/ to conclude that

the )*1.8(125(0 A thermoelectric will work in the given application

-aterial used for insulation

: The material used for the assembly components deserves careful thought. The

heat sink and cold side mounting surface should be made out of materials that

have a high thermal conductivity !i.e./ copper or aluminum$ to promote heat

transfer.

: +owever/ insulation and assembly hardware should be made of materials that

have low thermal conductivity !i.e./ polyurethane foam and stainless steel$ to

reduce heat loss.

: @nvironmental concerns such as humidity and condensation on the cold side

can be alleviated by using proper sealing methods. perimeter seal "Fi;@r2 %)

protects the couples from contact with water or gases/ eliminating corrosion and

thermal and electrical shorts that can damage the thermoelectric module.

: Typical thermoelectric from -elcor with a perimeter seal


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!28$

3ig(11

=ingle =tage vs. -ultistage

: Biven the hot side temperature/ the cold side temperature and the heat load/

a suitable thermoelectric can be chosen. f T across the thermoelectric is less

than "" )/ then a single stage thermoelectric is sufficient. The theoretical

ma#imum temperature difference for a single stage thermoelectric is

between " ) and 50 ).


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!2"$

f T is greater than "" )/ then a multistage thermoelectric should be

considered. multistage thermoelectric achieves a high T by stacking as

many as si# or seven single stage thermoelectrics on top of each other.

P2rfor3:n52

Fig 12 Performance Analyses Between Existing And Thermoelectric Model (cooling Graph)

The above graph depicts the plot of time in minutes and load

temperature in degree )elsius for thermoelectric model ande#isting domestic model. 3rom the graph/ it is clear that thermoelectric modelattains the minimum temperature about 7 )in 80 minutes and maintains the same/ where as the e#isting model takes 1hour toattain the same. 3urther the thermoelectric model maintains 7 ) for nearly "hoursand then it starts decreasing as shown. where as in e#isting model negative


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!2 $

temperature is achieved after 8 hours 10 minutes of time. This is the only

disadvantage of the thermoelectric model in which the time taken to free?e is more.

Fig-13 Performance Analyses Between Existing And Thermoelectric Model (Heating Graph)

This graph depicts the time taken to heat cabinet from 7 ). This is the deviationobserved from domestic refrigeration system and thermoelectric refrigeration

system. Thus both +eating U )ooling are achieved using *eltier modules and it ise#perimentally evaluated.

M:62ri:4/ @/28 6o >@i46 612r3o5o@


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!25$


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!29$


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> +/r$ f !$r -# 6

!60$


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Figure423)onventional cooling systems such as those used in refrigerators utili?e acompressor and a working fluid to transfer heat. Thermal energy is absorbed andreleased as the working 3luid undergoes e#pansion and compression andchanges phase from li%uid to vapor and back/ respectively. =emiconductor thermoelectric coolers !also known as *eltier coolers$ offer several advantagesover conventional systems. They are entirely solid(state devices/with no moving parts> this makes them rugged/ reliable/ and %uiet. They use noo?onedepleting chlorofluorocarbons/ potentially offering a more environmentallyresponsible alternative to conventional refrigeration. They can be e#tremelycompact/ much more so than compressor(based systems

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ADVANTAGES OF THERMOELECTRIC REFRIGERATION

: Co342 C )arries with one hand and is unaffected by motion or

tilting.

: Lo 2r Pri5280 20 to 80 less e#pensive than compressor or

absorption units.: Lo B:662r C verages appro#imately 8. " amps less than your cars

headlights.

DRA!0

: B:662r Pro6256ion0 Ised in combination with the LoolatronKMattery =averK you can always be assured of having starting power.

: P2rfor3:n520 Loolatron coolers maintain KcoolK temperatures inambients up to 90 degrees 3 .

: H2:6in; Oi4i6 0 Thermoelectrics have a 80 year proven track record in

military/ aerospace/ laboratory/ and now consumer applications.: E:/ S2r9i520 -ost parts are easily replaced by the enduser with a

screw driver.


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!62 )• Lo M:in62n:n520 The only maintenance re%uired with any

Loolatron unit is periodic. KdustingK and acuuming to ensure goodheat dissipation .

COMPARISON OF THERMOELECTRIC REFRIGERATION

:n8 OTHER METHODS OF REFRIGERATION

: T12r3o24256ri5 C )ooling is achieved electronically using theK*eltierK effect heat is pumped with electrical energy.

: Co3/or


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!66$!2i;16 C Loolatron units weigh 1&6 to 1&2 as much as the other units

because of the lightweight cooling system no heavy compressor.

Por6:>i4i6 C Loolatrons are the most portable because they are lightenough to carry with one hand and are not affected by motion or tilting.)ompressor models are %uite heavy and the absorption models must be keptlevel within 2 6 degrees.

Pri52 C Loolatron coolers cost 20 80 less than the e%uivalent si?edcompressor or absorption units available for recreational use.

B:662r Dr:in C Loolatron coolers have a ma#imum current drain on 12volts of 8. " amps. )ompressor portables draw slightly more current whenrunning but may average slightly less depending on thermostatic controlsettings. bsorption portables draw . " to 5. " amps when running and mayaverage about " amps draw .

B:662r Pro6256ion C )onsider the KMattery =averK option as discussed inthe previous section.

Coo4in; P2rfor3:n52 C )ompressor systems are potentially the mostefficient in hot weather. =ome models will perform as a portable free?er and will refrigerate in ambient temperatures of up to 110 degrees 3.Loolatron units will refrigerate in sustained ambient temperatures of up to9" degrees 3. f they are kept full/ they will refrigerate satisfactorily evenif peak daytime temperatures reach 110 degrees 3 because the contentstemperature will lag behind the ambient. The food will be just starting towarm up when the air cools off in the evening which will bring the foodtemperature back down to normal. bsorption type refrigerators provide

almost the same cooling performance as Loolatron portables but are lessefficient at high ambients.

Fr22 in; I52 C@>2/ C )ompressor systems will usuallymake a %uantity of small ice cubes. Bas absorption systems can do the same e#cept in hot weather. Loolatronthermoelectric units do not make ice cubes but can preserve them in a


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!68$ plastic container for 2 6 days which is often ade%uate for mostapplications.

S:f26 C Loolatron systems are completely safe because they use no gasesor open flames and run on just 12 volts. )ompressor systems can leak freon which can be e#tremely dangerous especially if heated. bsorptionsystems may use propane which can be e#tremely dangerous in the event of a leak.

R24i:>i4i6 C Loolatrons thermoelectric modules do not wear out or deteriorate with use. They have been used for military and aerospaceapplications for years because of their reliability and other uni%ue features.)ompressors and their motors are both subject to wear and freonfilled coilsare subject to leakage and costly repairs. bsorption units are somewhattemperamental and may re%uire e#pert servicing from time to time/especially if jarred when travelling.

EASE OF SERVICING AND MAINTENANCE0 Loolatron unitshave only one moving part/ a small fan !and 12 volt motor$ which caneasily be replaced with only a screw driver. -ost parts are easily replaced

by the enduser. )ompressor and absorption units both re%uire trained!e#pensive$ mechanics and special service e%uipment to service them.

Logistic Circuitry

The logistic circuitry is isolated from the high voltage high current circuitry by asolid state relay !==;$. n 3igure 1/ the basic logic of the circuitry is depicted.


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!6"$

Figure 16: Logistic Circuitry Flowchart

The -icro()ontroller receives the set(point temperature from the user through a

three button interface. =oftware in the -icro()ontroller then compares the set(

point temperature to the temperature feedback from the temperature sensor. Output

of the temperature sensor is analog/ which means that it needs to be converted to a binary number for the micro(controller to be able to understand it. This is done by

an analog to digital converter. The nalog to digital converter uses a five volt

precision voltage reference in order to perform the transformation from analog to

digital. n the final step/ the software in the micro controller determines whether or

not to turn the thermo electric modules on or off. The temperature inside the bo# is

then displayed on a li%uid crystal display for the user to see.

D29i52 T2/6in;


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!65$

Fi;@r2 #&0 T12r3o5o@r:6ion C@r92

This was remedied by e#cluding the data for the first and last five degrees on

the curve. We felt that this was acceptable since the range of our device is

only five to 2" Y). The ; 2 value for this arrangement was 0.9999 which

indicated an almost perfect linear correlation.

!67$


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Fi;@r2 #*0 In62rior T23


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!80$

Fi;@r2 $(0 R2/@46/ fro3 Coo4in; of !:62r

T23


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Fi;@r2 $#0 # Li62r of !:62r 5oo428 6o : /26


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Fi;@r2 $$0 Con6ro442r C1:r:562ri/6i5/

When the temperature of the water dips below its set point temperature/ thetemperature of the internal heat sinks is seen to spike. This phenomenon is

e#plained by how the controller works. The temperature sensor sends back a

temperature signal to the micro(controller. =oftware in the micro controller


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then compares the temperature to the set point temperature. t notices that

the temperature is below the set point temperature/ so the thermo electric

!86$

modules are switched on. The temperature of the heat sinks rise until thetemperature of the water returns to its set point temperature/ the thermo

electric modules are then turned off and the cycle continuous throughout

steady state conditions.

T:>42 #0 Pr25i/ion of 612 Coo42r

Z


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!88$For528 92r/@/ N:6@r:4 Con9256ion

When we initially designed our device we anticipated using forced

convection on the e#terior heat sinks. To test our design in this regard we

placed thermocouples on both e#terior heat sinks and a third inside the bo#

to monitor the interior heat sink temperature. Within ten minutes the e#terior

heat sink that was relying solely on natural convection had risen to a

temperature of "8 Y)/ while the forced convection heat sink maintained a

temperature of only 6 Y). The slope of the graph also indicated that the

temperature of the heat sink without the fans would have kept rising to a

significantly higher value had we not switched off the device and allowed it

to cool down. This demonstrates that it is imperative that there be a thermal

cut(off switch wired into the circuitry of our device.


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!8"$

T:>42 $0 ##For528 Con9256ion 9/ N:6@r:4 Con9256ion T2/6

Ti32 Con/6:n6/

Ising data obtained during both the air and water tests it is possible to

compute time constants for the system. The time constant for the air test was

appro#imately half an hour. The time constant for the system during the

water test was roughly two and three %uarter[s hours. This is a large

difference however the heat capacity of the water sample was far greater

than that of only the air during the first test.


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!85$

Co2ffi5i2n6 of P2rfor3:n52 C:45@4:6ion "COP)

)O* is as measure of the performance of a heat pumping device. t isdefined as the heat re%uired removing the heat divided by the actual heatremoved. The device was measure to draw ".2 mps of current at 11.2 olts.This results in a power consumption of "7." Watts.

3or the calculation of )O*/ it was assumed that only the air inside the bo#was cooled together with the aluminum heat sinks. +eat loss from the insideof the cooler to the outside was assumed to be ?ero during the cooling of the

bo# as it is a transient process.

;efering to 3igure / it took 000 seconds for the temperature of the air toreach " degrees )elsius from a starting temperature of 20 degrees )elsius.The volume of the inside air is 0.01" 2"m\6 and the volume of the internalheat sinks are 2R0.0001875m\6. IsingC

)O* Q *delivered R time & E -)!T2(T1$]air ' -)!T2(T1$]aluminumF

WhereC

*delivered Q !".22 $!11.2 $! 000s$ Q 6"1 L,-)!T2(T1$]air Q !0.01" 2"m\6R1.2kg&m\6$R!1000,&Lgo)$!2"(1"$Q271.2",-)!T2(T1$]aluminumQ!2R0.0001875 m\6R2500 kg &m\6$!900,&Lgo)$R!2"(1"$ Q 10780,

ThenC

)O* Q 11121.2"&6"1/000)O* Q 0.0615This low )O* shows the inefficiency of the device. Thermo electric modulesare inherently inefficient. )ommercial products are working on an efficiencythat is about " of the )arnot efficiency.


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!87$

S:f26 I//@2/

=afety is the first priority whenever using any type of industrial e%uipment.Through the building process/ there were several areas where safety precautionsneeded to be e#ercised.

Ho6 irin; S6 rofo:3

=tyrofoam was used for the insulation and to form a plug for the constructionof the inner bo#. n electric hot wire kit was used to cut the foam. )are must betaken to work in a well ventilated area and to wear eye protection and gloveswhen handling the hot wire device s well/ the hot wire gave off a mild electricshock if contacted Bloves eliminated this problem.

Fi>2r;4:// The inner bo# was constructed from fiberglass. t was important to work in awell ventilated area to protect from fumes. Aate# gloves provided e#cellent

protection from the wet resin when forming the fiberglass and were easy to disposewith 3ace masks were used when sanding hardened fiberglass to prevent breathingin abrasive particles.

!248in; :n8 Grin8in;

The frame of the cooler was constructed from ^ steel tubing. When welding/an approved welding mask was utili?ed to avoid permanent eye damage frome#posure to the brilliant light of the welding arc. The use of gloves and eye

protection and flame retardant clothing were also employed to prevent burndamages. dditionally all welding was done in a well ventilated area tominimi?e e#posure to welding fumes.


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!89$

B2n8in; :n8 Cri3


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3ortunately/ the power supply is sealed off and electrically isolated. s long as the power supply is not disassembled and a proper 6 prong plug

!"0$

connector is employed/ it should not pose a safety threat. Whenever electricalcomponents are being worked on/ ensure that the power cord is disconnectedfrom the wall plug.

nother safety issue when using the bo# is its weight. The bo# weighs about80 lbs and care must be taken to put it on a flat level surface when being used.The surface should also be stable. This will ensure that the bo# will not fall when being used possibly causing injury to the user and definitely damagingthe bo#.

=ome of the edges on the bo# are somewhat sharp. s much as possible/ wehave grinded and sanded down the edges of the panels. Moth the top panel andthe sheet metal on the lid have had the seams T B welded by lbert so that nosharp edges or corners would be e#posed when the bo# is assembled. +owever/if the bo# is disassembled to change the thermo(electrics or to make changes tothe controller/ special care must be e#ercised. The fit of the panels is %uite snugso attention must be paid when popping panels into place.

This device contains sensitive electrical e%uipment. t should be operated inan area where static electricity is not present. The user should ensure that theyare well grounded and not statically charged when handling any of the electricalcomponents of the device. lthough there is no danger posed to the user bystatic electricity/ components could be damaged or ruined/ re%uiringreplacement and or reprogramming.3inally/ the temperature at the thermoelectric modules is a concern. ttemperatures above 50 )/ the bismuth telluride material will melt and themodules will subse%uently fail. To avoid this potential problem/ a thermostaticswitch has been installed in the device. This switch is to be attached to one of

the e#ternal heat sinks on the cooler. t is wired inline with the power supply tothe thermo electrics. f the temperature of the heat sinks e#ceeds "0 )/ the

power to the thermoelectric is cut and the unit stops producing heat. Thisfeature is essential to ensure long life of the thermoelectric modules.


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!"1$

CHAPTER ' D26:i4/ of


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$30&

Con6ro442rThe controller for the device was changed from a * J controller to an O4&O33

controller. The microcontroller that was purchased by the design group was

capable of being programmed with a variety of control routines. The design team

naturally wanted to go with the more comple# solution of a * J controller in order

to be assured of getting the best response.

fter testing our device and discovering its response characteristics we have

learned that the most complicated solution is not always the best. The O4&O33

control reaches its target temperature at the heat transfer arrangements ma#imum

capacity and delivers no overshoot due to the inherent damping of the device. The

ability of the O4&O33 controller to maintain a constant temperature was also

proven to be more than sufficient.

F:n T


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lead to a small decrease of useful volume on the inside of the cooler as well as

making the cooler larger in its outside dimensions.

!"6$

T23


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controller programming.

_ !"8$

A88i6ion:4 f2:6@r2/ :n8 i3


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arrangement met this re%uirement but just barely. lso there was no re%uirement on

the cooling time/ which was found to be rather long.

!""$

f another heat transfer arrangement similar to the two currently in thedevice was added both the minimum temperature and the time of cooling would be

decreased significantly. This would mean a total of three thermoelectric modules

and si# heat sinks.

f another thermoelectric module were to be added to each of the e#isting

heat transfer arrangements the cold heat sink temperature could be reduced

dramatically and free?ing of the interior chamber would be possible. t is predicted

that that could cause two problems. 3irstly the controller currently does not register

temperatures below ?ero degrees )elsius making control below free?ing

temperatures impossible without reprogramming. =econdly the air bath was not

designed with the possibility of free?ing condensation in mind. This could possibly

cause damage to the heat transfer pipes.

The current power supply in the device should be able to power two more

thermoelectric modules according to its specifications.

R25:4i>r:6ion

t has been noted in testing that the device maintains and displays a temperature

that is not e#actly representative of the actual temperature inside the chamber. To

rectify this problem the device must be recalibrated using accurate voltage and

temperature data measured over the entire operating temperature range of the

device. The new more accurate calibration curve would then have to be put into the

micro(controller programming in place of the e#isting calibration curve.


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!" $

Por6:>i4i6t could be possible to make this device more useful if it were capable of being

operated from a battery pack or a solar collector. This option would allow for thedevice to be used in areas without electricity as well as in vehicles. 3or this to be

possible the performance and energy efficiency of the device would have to bema#imi?ed. There are two key ways that the efficiency of the device could beincreased. 3irstly the O4&O33 control could be replaced with a * J control inorder to use the thermoelectric modules at a lower power while they are on. This

will increase the efficiency since thermoelectric modules generate e#cess heat asthe power input is increased lowering their performance. =econdly additionalthermoelectric modules could be added to decrease the load on each individualmodule. The lower the load the more efficiently the modules will run.

P OPO!"# !$!%"&

The A-6" series are precision integrated(circuit temperature sensors/ whoseoutput voltage is linearly proportional to the )elsius !)entigrade$ temperature. TheA-6" thus has an advantage over linear temperature sensors calibrated in Lelvin/as the user is not re%uired to subtract a large constant voltage from its output toobtain the convenient )entigrade scaling. The A-6" does not re%uire any e#ternalcalibration or trimming to provide typical accuracies of `1 8 ) at roomtemperature and `6 8 ) over a full "" to '1"0 ) temperature range. Aow cost isassured by trimming and calibration at the wafer level. The A-6"[s low outputimpedance/ linear output/ and precise inherent calibration make interfacing toreadout or control circuitry especially easy. t can be used with single power supplies/ or with plus and minus supplies. The temperature sensor A-6" senses thetemperature and convert it into an electrical signal which is applied to themicrocontroller through the J). The temperature range of the sensor is 1 to ℃


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2"" . *eltier cooler is used as a thermo(electric generator. When operated as a℃

cooler/ a voltage is applied across the device/ and as a result/ a difference in

!"5$

temperature will build up between the two sides. When operated as a generator/one side of the device is heated to a temperature greater than the other side/ and asa result/ a difference in voltage will build up between the two sides.

Fig40E

E3>28828 Uni6/

The temperature control chamber provides the user with an accurate range of ambient temperature. The chamber is shown in the figure. 6. The user can buildthis simple circuit and protect any issues with temperature. -oreover/ it is easy todevelop depends on the environment or re%uirement that is needed for differenttypes of testing.


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!"7$

3ig(29

T232r

lso/ using the variable resistors allows user to be fle#ible to the ambienttemperature when the temperature is one of the variables in the testing.Thechamber consists of hot and cold chamber for both the purposes. Table 1 shows thespecifications of the temperature controlled chamber

P://i92 H2:6 Lo:8


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The passive heat load for the unit was first calculated based upon a2"cm # 2"cm # 2"cm interior volume. Two inches of polystyrene insulatedwas assumed !kQ0.025w&mL$. lso included were a rubber seal on the door which was "0 cm2 in area.

!"9$

xT

k xT

k q rubber instot ∆∆

+∆

∆=

!6$

whereC %tot is the heat transfer in watts/ k ins is the resistance to heat transfer/and k rubber is 0.018w&mL PT is assumed to be 20 ) and P# is 0."0m.This gives a % tot of 10 W.

A56i92 H2:6 Lo:8

The active heat load is the e%uivalent of the cooling power that the unit willneed to provide when the sample at room temperature is placed in thecontainer. t was decided that one liter of water at room temperature would

be the test sample for which all calibration and calculations would be made.The time to cool this load from 2" ) to " ) was determined to be 1 hour/or 6 00 seconds. Mased on these valuesC

T mcQ p ∆= !8$

f the )p of water is 8.18 L,&kgRL/ then S Q 72700, and dividing by 6 00sto get power !W$/ S dot Q 26 W for the active heat load. Therefore/ the totalload is 26 ' 11 W Q 68 W of power re%uired. This assumes that there is nothermal resistance between the sample and the air in the unit. This may be anincorrect assumption but it does overestimate the cooling load.


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H2:6 Lo:8 R2 @ir28 6o >2 Di//i H2:6 Sin?

The *eltier module is running at 12 and ".2 amps of current. The followingin vs. graph shows a normal operating range of the T@-.

! 0$

Fi;@r2 +(0 T12r3o24256ri5 Mo8@42 P2rfor3:n52

The power consumed by the T@- is assumed in the worst case scenario to be added to the heat on the hot side.

2

or safetyfact sample passiveTEC hot

QQQ P q

+++=

!"$Jivision by two denotes that we have two T@-[s/ two hot side heat sinksand two cold side heat sinks to improve system efficiency. Therefore/ % totQ105W. This is the ma#imum heat load to the hot side of each T@) andtherefore each of the heat sinks.


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M: i3@3 T23


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! 2$


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3ig(62

! 6$

E4232n6/ U/28

: ; Transmitters # 6

: ; ;eceivers # 6

: A@J ;ed # 2

: A@J Breen # 1: A@J Xellow # 1

: 7bit -icrocontroller i.e T-@B 7 for processing

: J) -otor # 1

: ) A296J for -otor Jriver )ircuit

: 10L *reset ! ariable ;esistance$

: 10L #1 ;esistance/ 1"0; #1 ;esistance

: 22p3 #2 )apacitance/ 1000u3 #1 )apacitance

: )rystal Oscillator 6."5 -+?

: 12 J) dapter =ocket

: 6 pin )onnector


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: +eat =ink

: 570" !" oltage ;egulator$

: pin *ower =witch

: Beneral *urpose *)M: =oldering ron

: =older

: )onnecting Wires

: Other necessary components

! 8$

Fig-33

L CD D ISPLAY


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li%uid crystal display !commonly abbreviated A)J$ is a thin/ flat display devicemade up of any number of color or monochrome pi#els arrayed in front of a lightsource or reflector.

! "$

3ig 68 nterfacing Acd With *ic 1 f755a

t is often utili?ed in battery(powered electronic devices because it uses very smallamounts of electric power. n this system A)J is used to display the current


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temperature values in ) along with indication whether system is in cooling modeor heating mode. t receives input regarding this information from the microcontroller

! $

Fig-35


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Light "'itting #iodes#iode !y'bol ( )rrows *or lightPoints to ground

(67)

Fig-36


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(68)


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Fig-37


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(69)

Chapter +: Conclusion and Futureeco''endations

Conclusion

s the constant temperature air bath has met nearly all of its re%uirements.

recalibration of the device would be re%uired before all of the re%uirements

are met.

Juring construction of the device several minor changes were made to the

design. @ach of these changes we feel was justified as they made for easier

construction while maintaining the performance of the device with respect to

the project goals. The device passed its final inspection and was deemed to

have a professional appearance by the design project coordinator.

The performance characteristics of the final device were tested thoroughly

with the assistance of the Jalhousie )hemistry Jepartment and presented in

this report. The device was discovered to have ample precision and total heat

transfer capabilities while not meeting its accuracy re%uirement.

Future eco''endations

There were several aspects of the design that were changed during the

building phase of the project. Isually these changes were made for ease of

construction. =ome of the changes were made as a result of test data

received from the mockup. n this section each of these changes are

received from the mockup. n this section each of these changes .


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(70)

Chapter ,: e*erences

[1] Shun Chen, Jun Zuo and Dan Xie De!ign o" !o#a$ %o&e$ !e'i ondu o$ $e"$ige$a o$* in he %$o eeding! o" he 8 h +o$#d Cong$e!! on n e##igenCon $o# and u o'a ion Ju#. 6-9 /010, Jinan, China[/] aida$ S, !aa 2he$'o-e#e $i Coo#ing !ing 4e# ie$ Ce##! inCa! ade, *(/00 )[3] San a. u'a$ o$i a$ and da. S +an hede :%e$i'en a# ana#.!i!o" !o#a$ $e"$ige$a ion !.! e'* in he %$o eeding! o" he n e$na iona#Con"e$en e a 4u$due, Ju#. 1 -17, /008

[ ] So$ ;ii!hnu >a$dhan D, ?aa' @u'a$ 4 , Sai 4$a!ad, ?a'.a@ 4ho o


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Documents

Deepak Gangwar