AMRAR REPORT

REFRIGERATOR WORKING ON PELTIER
EFFECT WITHOUT COMPRESSOR
CAPSTONE PROJECT REPORT
Submitted in partial fulfillment of the requirement for award of the degree of
BACHELOR OF TECHNOLOGY
IN
MECHANICAL ENGINEERING
BY
Manas Adhikari 11102061
Imon Kalyan Goswami 11102141
Abhi Acharjee 11102060
Tamajit Datta 11106005
Under the guidance of
Mr. Puneet Sharma (Asst. Professor)
DEPARTMENT OF MECHANICAL ENGINEERING
LOVELY PROFESSIONAL UNIVERSITY
PHAGWARA, PUNJAB (INDIA) -144402

CERTIFICATE
I hereby certify that the work which is being presented in the capstone project / Dissertation
entitled “REFRIGERATOR WORKING ON PELTIER EFFECT WITHOUT
COMPRESSOR” in partial fulfillment for the award of degree of Bachelor of Technology
and submitted in Department of Mechanical Engineering, Lovely Professional University,
Punjab is an authentic record of my own work carried out during period of capstone under the
supervision of Mr. Puneet Sharma, Assistant Professor, Department of Mechanical
Engineering, Lovely Professional University, Punjab.
The matter presented in this project has not been submitted by means where for the award of
any other degree or to any other institute
This is to certify that the above statement made by the candidate is correct to best of my
knowledge.
Date: 28/04/2015 (Puneet Sharma)
Supervisor

ACKNOWLEDGEMENT
We would like to take this opportunity to thank all of the individuals who provided us with
words of knowledge, encouragement, and support through the process of my project. Without
your assistance this accomplishment would not have been possible.
Special thanks to our project mentor Puneet Sharma who provided great inspiration,
enthusiasm, and guidance during the course of the capstone project. His expertise,
knowledge, and most importantly his patience was invaluable throughout the development of
the project.
Finally, we would like to thank our families and friends for their continual love and support
during this experience.
“Thank You”

ABSTRACT
With the advent of household refrigeration system in 1910, the modification to the core
technology has been very less. The system has a compression machine designed for
continuous automatic operation and for conservation of the charges of refrigerant and oil, and
is usually motor driven and air-cooled. The compressor used is a power consuming
component. It consumes around 90% of the total rated consumption in a refrigerator.
This project emphasizes on the working of a refrigeration system which does not have a
compressor. The refrigerator has no rotary power consuming component, so the system has
greater life longevity. The working is based on Peltier cooling comprising of a Peltier
module. This is an energy efficient system consuming minimum power. Further, it also acts
as heater unit providing a localized heating. It is air-cooled system having no flow of
refrigerant. This further reduces the environmental concerns surrounding the use of
refrigerant, which has been part of great debate now-a-days. The system is solar powered.
This has been introduced as a step to have renewable source of energy.
With the shift to a sustainable environment in recent era, this project poses as an approach to
achieve it. This has the ability to be a next-gen refrigeration system for domestic use in
coming times.

CONTENTS
S.NO TITLE PAGENO
Certificate i
Acknowledgement ii
Abstract iii
List of Figures vi
1 CHAPTER 1: INTRODUCTION 1-3
1.1 Refrigeration 1
1.1.1 Non-cyclic Refrigeration 1
1.1.2 Cyclic Refrigeration 1
1.1.3 Thermoelectric Refrigeration 1
1.1.4 Magnetic Refrigeration 1
1.2 Background 2
1.3 Different Components 2
1.3.1 Major Components 2
1.3.2 Minor Components 3
2 CHAPTER 2: LITERATURE REVIEW 4-5
2.1 Introduction 4
2.2 Thermoelectric Modules 5
2.3 Development in Thermoelectric Refrigeration Systems 5
3 CHAPTER 3: PROBLEM FORMULATION 6
3.1 Scope 6
3.2 Objective 6
4 CHAPTER 4: DESCRIPTION OF THE COMPONENTS 7-20
4.1 Peltier Module 7-9
4.2 Cooling Fan 9-10
4.3 Heat Sink 10-12
4.4 Solar Cell Panel 12-14
4.5 Icebox 15-16
4.6 Battery 17
4.7 Wires 18

4.8 Two-way Switch 18-19
4.9 AC/DC Adapter 19-20
4.10 Aluminium Sheet 20
5 CHAPTER 5: DEVELOPMENT AND CONSTRUCTION 21-28
5.1 Design and Analysis 26-28
5.1.1 Design 26-27
5.1.2 Calculations/Analysis 27-28
6 CHAPTER 6: DISCUSSIONS 28-29
6.1 Advantages of Thermoelectric Refrigeration System 28
6.2 Comparison of Thermoelectric Refrigeration with other methods of
Refrigeration
28-29
7 CHAPTER 7: CONCLUSION AND FUTURE SCOPE 30
7.1 Conclusion 30
7.2 Future Scope 30
REFERENCES 30-31

LIST OF FIGURES
FIGURE
NO
TITLE PAGE
NO
1 Peltier Circuit
2 Peltier Module Structure
3 Cooling Fan
4 Heat Sink
5 Solar Panel
6 Icebox
7 Battery
8 Wires
9 Two-way Switch Circuit
10 AC/DC Adapter
11 Cut Icebox
12 Peltier Module and Heat Sink
13 Heat Sink
14 Connection between Peltier module and Fan
15 Connection of Two-way Switch
16 Battery connected to Solar Panel
17 Aluminium Sheet
18 Complete Setup
19 Model of Different Components
20 Complete Refrigerator Model

CHAPTER 1
INTRODUCTION
1.1 Refrigeration
Refrigeration is a process in which work is done to remove heat from one location to another.
Refrigeration has many applications, including household refrigerators,
industrial freezers, cryogenics, and air conditioning. Refrigeration has had a large impact on
industry, lifestyle, agriculture and settlement patterns. The idea of preserving food dates back
to the ancient Roman and Chinese empires. However, refrigeration technology has rapidly
evolved in the last century. The methods of refrigeration can be classified as non-cyclic,
cyclic, thermoelectric and magnetic processes.
1.1.1 Non-cyclic refrigeration: In non-cyclic refrigeration, cooling is accomplished by
melting ice or by subliming dry ice (frozen carbon dioxide). These methods are used for
small-scale refrigeration such as in laboratories and workshops, or in portable coolers.
1.1.2 Cyclic refrigeration: Cyclic refrigeration can be classified as:
1. Vapor cycle refrigeration, and
2. Gas cycle refrigeration
Vapor cycle refrigeration can further be classified as:
1. Vapor-compression refrigeration
2. Vapor-absorption refrigeration
1.1.3 Thermoelectric refrigeration: Thermoelectric cooling uses the Peltier effect to create
a heat flux between the junctions of two different types of materials. This effect is commonly
used in camping and portable coolers and for cooling electronic components and small
instruments.
1.1.4 Magnetic refrigeration: Magnetic refrigeration, or adiabatic demagnetization, is a
cooling technology based on the magneto-caloric effect, an intrinsic property of magnetic
solids. The refrigerant is often a paramagnetic salt, such as cerium magnesium nitrate. The
active magnetic dipoles in this case are those of the electron shells of the paramagnetic atoms.

Because few materials exhibit the needed properties at room temperature, applications have
so far been limited to cryogenics and research.
1.2 Background
In our project we are going to use thermoelectric refrigeration as a technique for
refrigeration. It uses the Peltier effect in order to produce refrigeration. The Peltier effect is
named after a French scientist who discovered it in 1834. In 1834 Jean Peltier noted that
when an electrical current is applied across the junction of two dissimilar metals, heat is
removed from one junction and transferred to the other. Thermoelectric modules are
constructed from a series of tiny metal cubes of dissimilar exotic metals which are physically
bonded together and connected electrically. When electrical current passes through the cube
junctions, heat is transferred from one metal to the other. Solid-state thermoelectric modules
are capable of transferring large quantities of heat when connected to a heat absorbing device
on one side and a heat dissipating device on the other.
The Peltier effect: The Peltier effect is a temperature difference created by applying a
voltage between two electrodes connected to a sample of semiconductor material. A Peltier
cooler, heater, or thermoelectric heat pump is a solid-state active heat pump which transfers
heat from one side of the device to the other, with consumption of electrical energy,
depending on the direction of the current. Such an instrument is also called a Peltier device,
Peltier heat pump, solid state refrigerator, or thermoelectric cooler (TEC). It can be used
either for heating or for cooling, although in practice the main application is cooling. It can
also be used as a temperature controller that either heats or cools.
The primary advantages of a Peltier cooler compared to a vapor-compression refrigerator are
its lack of moving parts or circulating liquid, very long life and invulnerability to potential
leaks, and its small size and flexible shape.

1.3 Different components
1.3.1 Major components
(i) Peltier unit
(ii) Fan
(iii) Heat radiator
(iv) Solar cell panel
(v) Ice box (12 Lt)
(vi) 12V battery
1.3.2 Minor components
(i) Wires
(ii) Two way switch
(iii) DC Adaptor
(iv) Aluminium sheet

CHAPTER 2
LITERATURE REVIEW
2.1 Introduction
The world is facing a critical problem of energy deficit which underlines the very existence
of survival. Global warming on the other hand is proving a major crisis to be dealt with. As
the world strives to solve the energy problem, there has been a growing interest in
strengthening education in renewable energy technologies and related fields which puts
importance on the study of interdisciplinary subjects.
An American society of refrigeration engineer has defined refrigeration as “the science of
providing and maintaining temperature below that surrounding atmosphere” [1].
Refrigeration is considered as the major contributor of technology for the humanity in many
ways. In this literature review, the focus is on designing such a system that has the
fundamentals to accomplish a given cooling task while minimizing electrical power input,
without the need of a compressor, which is completely based on thermoelectric cooling
technology with the use of solar energy. The research data available for this technology has
been reviewed here.
Xi Hongxia et al.[2007][2] studied that thermoelectric refrigeration emerges as the new green
technology due to their distinct advantages as noiseless and wearless due to no moving parts,
reliable, portable and compatible with solar PV cell generated DC power, making them
complete environment friendly.
Bansal et al.[2000][3] did a detailed comparative study on thermoelectric, vapor compression
and absorption refrigeration system to compare the development cost, energy consumption,
noise intensity production and COP for these three systems.

2.2 Thermoelectric modules
Thermoelectric semiconductor materials were first developed in the 1950’s. Since 1960’s
improvement in the quality control was made.
2.3 Developments in thermoelectric refrigeration systems
Dai et al. [2003][4] devised a thermoelectric refrigeration system powered by solar cells and
analyzed the process. They developed a prototype which maintained a temperature at 5-10 C,
and COP about 0.3 under suitable conditions.
Min et al.[2006][5] devised various prototypes of thermoelectric domestic refrigerator with
the combination of heat exchangers and evaluated the cooling performance with respect to
COP, heat pumping capacity, cooling down rate and temperature stability. They concluded
that liquid operated thermoelectric refrigerators possess a lower COP than a forced air
convection system.
Wahab et al.[2009][6] developed a thermoelectric refrigerator using a combination of
modules to reduce the temperature of the refrigerated space from 27 C to 5 C in about 44
minutes. The COP was calculated and found to be about 0.16.

CHAPTER 3
PROBLEM FORMULATION
3.1 Scope
 To reduce the electricity consumption of refrigeration system by employing
thermoelectric technology (Peltier Effect).
 To use solar energy as the alternative power source of the refrigerator.
3.2 Objective
The main objective of the project is to make an economical and portable refrigerating
system which will not use a compressor or any other moving devices. In addition to the main
objective, the power source used to drive the refrigerator is also taken into consideration.
Here the power source is based on a renewable source, solar energy.

CHAPTER 4
DESCRIPTION OF THE COMPONENTS
4.1 Peltier Module
Peltier Module is most essential part in our project. Peltier module consists of an array of
semiconductor pellets that have been doped so that one type charge carrier either positive or
negative carries the majority of current. Two semiconductors, one p-type & another n-type
having different electron densities are used (1). N-type material is doped so that it will have
an excess of electrons (more electrons than needed to complete a perfect molecular lattice
structure) & P-type material is doped so that it will have a deficiency of electrons (fewer
electrons than are necessary to complete a perfect lattice structure). The extra electrons in the
N material and the holes resulting from the deficiency of electrons in the P material are the
carriers which move the heat energy through the thermoelectric material. Most thermoelectric
cooling modules are fabricated with an equal number of N-type and P-type elements where
one N and P element pair form a thermoelectric couple. Semiconductors placed thermally in
parallel to each other & electrically in series to each other metalized ceramic sheets are used
as a cover. Semiconductors are connected by side by side & are sandwiched between two
ceramic plates (2).There are also two free ends exists which are connected to applied voltage.
This unit works on Peltier theory which is already described earlier. When DC voltage is
applied to the module, semiconductors absorb heat energy from one ceramic sheet surface &
release it to another surface where the heat sink is. The surface where the heat energy is
absorbed becomes cold & the opposite surface where heat energy is released becomes hot.
This phenomenon can be reversed by a change in the polarity of applied DC voltage causing
the heat to be moved in opposite direction .Thus temperature difference occurs. Most
thermoelectric modules range in size from approximately 2.5-50 mm (0.1 to 2.0 inches)
square and 2.5-5mm (0.1 to 0.2 inches) in height (2).It is generally suitable for precise
temperature control applications. It is generally used as a cooing unit for portable coolers,
cooling electronic components & small equipments. Its heat emission side can be used for
keeping the food warm & other heating purposes. They are used for cooling the computer
components & also in satellites. It also can be used for power generation. Cooling capacity is
proportional to the magnitude of applied DC voltage & the thermal conditions on each side of
the module.

Fig 1: Peltier Circuit
Benefits of using peltier module as a cooler units are given below:
 No moving parts & easy maintenance
 No refrigerants/chlorofluorocarbons
 Flexible shape
 Heating & cooling with same module
 Wide operating temperature range
 Environmentally friendly
 Acoustically silent
 Can be used in environments which are severe for conventional refrigeration
 Long life
Although it has several advantages, some disadvantages of using module also exist.
 Dissipation of limited amount of heat flux
 Low coefficient of performance
 Low Efficiency compared to conventional refrigerators(1)

Fig 2: Peltier Module Structure
4.2 Cooling Fan
Fan is a machine used to create flow with in a fluid, typically gas such as air. Fan consists of
a rotating arrangement of vanes or blades which act on the fluid. Blades are attached on the
periphery of a hub called as impeller & the rotating assembly is known as runner or rotor. All
the moving parts are enclosed in a case. This directs the air flow as well as act as a safeguard
for the other components from the moving blades. Most fans are powered by electric motors,
but other sources of power may be used (such as hydraulic power).Fan is generally used for
cooling purposes besides it has also other application. Cooling fans become essential
component in nearly all electronic equipments (3).Fan’s purpose to ensure cool operating
temperature. It draws the cooler air from outside atmosphere & expels warm air from inside
to maintain suitable operating temperature. It applies right amount of cool air to the
components, protecting against heat that can harm electronics & effects the performance. Its
angled blades guide air outside of the device into the device where the heat emission occurs,
in a single direction. It also dejects the warm air from the inside of the device (4).
Today fans having various sizes, shapes, colors etc are installed in the electronic devices. The
size & shape of the apparatus decides the size of the cooling fan. The cooling capability of
fan depends upon its size, speed & power consumed. A fan that can spin at higher rotation
per minute will funnel more air into the device than a slower fan.
In this device a fan is incorporated under the lower side of the heat radiator. When heat
generates at the hot junction of peltier module, it extracts heat from the source & provide cool
air to maintain operating temperature.12V DC-0.18A fan is used in this device. It is sleeve
bearing type made by Chiefly Choice Company Ltd.Dimensions of this fan are
200mm*200mm*60mm (W*L*H).

Fig 3: Cooling Fan
4.3 Heat Sink
Radiators are heat exchangers used to transfer heat from one medium to another medium for
the purpose of cooling & heating. Radiator is a source of heat to its environment, although
this may be for either heating purposes, or cooling the components. The heating radiator was
invented by Franz San Galli, Russian businessman in 1855.In electronic devices we generally
use heat sink as a radiator. A heat sink is a passive heat exchanger that cools a device by
dissipating heat into surrounding medium. Heat is transferred to the air by conduction and
convection; a relatively small proportion of heat is transferred by radiation owing to the low
temperature of semiconductor devices compared to their surroundings (5).
A heat sink transfers thermal energy from a higher temperature device to a lower
temperature fluid medium. The fluid medium is frequently air, but can also be water,
refrigerants or oil. If the fluid medium is water, the heat sink is frequently called a cold plate.
In thermodynamics a heat sink is a heat reservoir that can absorb an arbitrary amount of heat
without significantly changing temperature. Practical heat sinks for electronic devices must
have a temperature higher than the surroundings to transfer heat by convection, radiation, and
conduction. The power supplies of electronics are not 100% efficient, so extra heat is
produced that may be detrimental to the function of the device. As such, a heat sink is
included in the design to disperse heat to improve efficient energy use.

From the Fourier’s Law of Heat Conduction & Newton’s Law of Cooling we can determine
how much heat transfer happens by conduction theoretically.
To design a heat sink there are some factors must be followed which are given below:
 Thermal resistance
 Material
 Fin efficiency
 Spreading resistance
 Shape of the fins
 Location of the fins
 Fin arrangements
 Conductivity of the material
 Surface color
The popular heat sink materials are aluminium alloys. Aluminium alloys 6061 & 6063 are
commonly used. Copper also has excellent heat sink properties. Diamonds, composite such as
copper-tungsten alloy, AlSiC & Dymalloy etc are also used for heat sink materials. There are
also various types of fin arrangements in heat sinks such as pin fin, straight fin, flared fin etc.
In general, the more surface area a heat sink has, the better it works. However, this is not
always true. The concept of a pin fin heat sink is to try to pack as much surface area into a
given volume as possible. We used straight fin heat sink as a heat dissipator.
As power dissipation of components increases and component package size decreases,
thermal engineers must innovate to ensure components won't overheat. Devices that run
cooler last longer. A heat sink design must fulfill both its thermal as well as its mechanical
requirements. Concerning the latter, the component must remain in thermal contact with its
heat sink with reasonable shock and vibration. The heat sink could be the copper foil of a
circuit board, or else a separate heat sink mounted onto the component or circuit board.
Attachment methods include thermally conductive tape or epoxy, wire-form z clips, flat
spring clips, standoff spacers, and push pins with ends that expand after installing. They are
used in microprocessor cooling, cooling of other heat emission components such as light
emitting diode lamps & for soldering purposes.
In our device heat sink is placed between peltier module & 12V DC fan. It is straight fin type,
portable & it is adhered by ceramic paste adhesive.

Fig 4: Heat Sink
4.4 Solar Cell Panel
Solar panels are devices that convert light into electricity. They are called solar panels
because most of the time, the most powerful source of light available is the Sun, called Sol by
astronomers. Some scientists call them photovoltaic which means, basically, "light-
electricity”. A solar panel is a collection of solar cells. Lots of small solar cells spread over a
large area can work together to provide enough power to be useful. The more light that hits a
cell, the more electricity it produces. Solar panel refers either to a photovoltaic module,
a solar hot water panel, or to a set of solar photovoltaic modules electrically connected and
mounted on a supporting structure. A PV module is a packaged, connected assembly of solar
cells. Solar panels can be used as a component of a larger photovoltaic system to generate
and supply electricity in commercial and residential applications. Each module is rated by
its DC output power under standard test conditions, and typically ranges from 100 to 320
watts. The efficiency of a module determines the area of a module given the same rated
output. A single solar module can produce only a limited amount of power; most installations
contain multiple modules. A photovoltaic system typically includes a panel or an array of
solar modules, an inverter, and sometimes a battery and/or solar tracker and interconnection
wiring. If we can harness the solar power efficiently, then we may not need to rely on burning
fossil fuels for energy.
Solar modules use light energy (photons) from the sun to generate electricity through
the photovoltaic effect. The majority of modules use wafer-based crystalline silicon cells
or thin-film cells based on cadmium telluride or silicon. The structural (load carrying)
member of a module can either be the top layer or the back layer. Cells must also be
protected from mechanical damage and moisture. Most solar modules are rigid, but semi-
flexible ones are available, based on thin-film cells. These early solar modules were first used
in space in 1958.
Electrical connections are made in series to achieve a desired output voltage and/or in
parallel to provide a desired current capability. The conducting wires that take the current off
the modules may contain silver, copper or other non-magnetic conductive metals. The cells

must be connected electrically to one another and to the rest of the system. Externally,
popular terrestrial usage photovoltaic modules use MC3 or MC4 connectors to facilitate easy
weatherproof connections to the rest of the system. Bypass diodes may be incorporated or
used externally, in case of partial module shading, to maximize the output of module sections
still illuminated. Some recent solar module designs include concentrators in which light is
focused by lenses or mirrors onto an array of smaller cells. This enables the use of cells with
a high cost per unit area (such as gallium arsenide) in a cost-effective way.
Most modules are currently produced from solar cells made of
polycrystalline and monocrystalline silicon. In 2013, crystalline silicon accounted for more
than 90 percent of worldwide PV production. Most parts of a solar module can be recycled
including up to 97% of certain semiconductor materials or the glass as well as large amounts
of ferrous and non-ferrous metals. Some private companies and non-profit organizations are
currently engaged in take-back and recycling operations for end-of-life modules. Panels can
be mounted in a various way such as ground mounting, roof mounting, pole mounting,
ballasted footing mountings etc (6).
In this device 36 cell solar photovoltaic module is used which has maximum50.00 watt power
& 2.85A current at maximum power. Its dimensions are 576*666*34mm (L*W*H) &
tolerances will be 1.5 mm (7).
Fig 5: Solar Cell Panel

4.5 Ice Box
An icebox or cold closet is a compact non-mechanical refrigerator which was
common kitchen appliance before the development of safe powered refrigeration devices (8).
The Ice Box is a Food Tab structure used to store and preserve Food, reducing spoilage rate
by 50% (so edible items stored in an Ice Box will last twice as long before spoiling).
Commonly iceboxes were made of wood, most probably for ease of construction, insulation,
and aesthetics: Many were handsome pieces of furniture. But this ice box is made of thermo
setting plastic & thermocol. Its wall is insulating. The following items can be placed in the
ice box: many food items, petals & ice (9). As food spoils faster in summer, it is
recommended players put their food in the Ice Box to slow down the spoiling rate of food and
help preserve food for Winter. It is portable & in the lower part the cold junction of the
peltier module is exposed. Inner surface of box is covered by aluminium sheets because it
helps in uniform transfer of heat. It is easy to carry, easy to dispatch & easy to assemble.
Fig 6: Ice Box

4.6 Battery
An electric battery is a device consisting of one or more electrochemical cells that convert
stored chemical energy into electrical energy. Each cell contains a positive terminal or
cathode and a negative terminal, or anode. Electrolytes allow ions to move between the
electrodes and terminals, which allows current to flow out of the battery to perform work.
Primary (single-use or disposable) batteries are used once and discarded; the electrode
materials are irreversibly changed during discharge. Common examples are the alkaline
battery used for flashlights and a multitude of portable devices. Secondary (rechargeable
batteries) can be discharged and recharged multiple times; the original composition of the
electrodes can be restored by reverse current. Examples include the batteries used in vehicles
and lithium ion batteries used for portable electronics.
Batteries come in many shapes and sizes, from miniature cells used to power aids and
wristwatches to battery banks the size of rooms that provide standby power for telephone and
computer data centers.
According to a 2005 estimate, the worldwide battery industry generates US$48 billion in
sales each year, with 6% annual growth.
Batteries have much lower specific energy (energy per unit mass) than common fuels such as
gasoline. This is somewhat mitigated by the fact that batteries deliver their energy as
electricity which can be converted efficiently to mechanical work, whereas using fuels in
engines entails a low efficiency of conversion to work(10).
In this device two 6V rechargeable batteries are used. This Battery is charged by solar cell
panel.
Fig 7: Battery

4.7 Wires
A wire is a single, usually cylindrical, flexible strand or rod of metal. Wires are used to bear
mechanical loads or electricity and telecommunications signals. Wire is commonly formed by
drawing the metal through a hole in a die or draw plate. Wire gauges come in various
standard sizes, as expressed in terms of a gauge number. The term wire is also used more
loosely to refer to a bundle of such strands, as in multi-stranded wire, which is more correctly
termed a wire rope in mechanics, or a cable in electricity. Wire comes in solid core, stranded,
or braided forms. Although usually circular in cross-section, wire can be made in square,
hexagonal, flattened rectangular or other cross-sections, either for decorative purposes, or for
technical purposes such as high-efficiency voice coils in loudspeakers. Edge-wound coil
springs, such as the Slinky toy, are made of special flattened wire. Wire is often reduced to
the desired diameter and properties by repeated drawing through progressively smaller dies,
or traditionally holes in draw plates. After a number of passes the wire may be annealed to
facilitate more drawing or, if it is a finished product, to maximize ductility and conductivity
(11).
Fig 8: Wires
4.8 Two Way Switch
In electrical engineering, a switch is an electrical component that can break an electrical
circuit, interrupting the current or diverting it from one conductor to another. The mechanism
of a switch may be operated directly by a human operator to control a circuit (for example, a
light switch or a keyboard button), may be operated by a moving object such as a door-
operated switch, or may be operated by some sensing element for pressure, temperature or
flow(12).
Two way switch is used in multi-way switching having interconnection of two or
more electrical switches to control an electrical load (often, but not always, lighting) from
more than one location. 2 way switching means having two or more switches in different
locations to control one electrical operation. They are wired so that operation of either switch

will control a light. This arrangement is often found in stairways, with one switch upstairs
and one switch downstairs or in long hallways with a switch at either end (13).
Fig 9: Two Way Switch Circuit
4.9 AC/DC Adapter
AC/DC adapter or AC/DC converter is a type of external power supply, often enclosed in a
case similar to an plug. It has Other names include plug-in adapter, adapter block, line power
adapter, power brick and power adapter. Adapters for battery-powered equipment may be
described as chargers or rechargers (see also battery charger).AC/DC adapters are used with
electrical devices that require power but do not contain internal components to derive the
required voltage and power from mains power. The internal circuitry of an external power
supply is very similar to the design that would be used for a built-in or internal supply.
Originally, most AC/DC adapters were linear power supplies, containing a transformer to
convert the mains electricity voltage to a lower voltage, a rectifier to convert it to pulsating
DC and a filter to smooth the pulsating waveform to DC. Size and weight of the device was
largely determined by the transformer, which in turn was determined by the power output
and mains frequency (14).
We use 12V AC/DC Adapter in this system.

Fig 10: AC/DC Adapter
4.10 Aluminium Sheet
A sheet made of aluminium is used for heat conduction purposes. Aluminum is also a popular
metal used in sheet metal due to its flexibility, wide range of options, cost effectiveness, and
other properties. Aluminium’s thermal conductivity is 237 W/mK. Box is made of insulating
materials (15).So thermal conduction is not occurred that much if no thermal conductive
material is introduced inside. Aluminium has good thermal properties & its sheet provides
uniform heat conduction throughout its surfaces. So sheet is attached at inner surface by
screws.
Apart from this four clamps are incorporated beneath the ice box to hold device position &
balance its mass.

CHAPTER 5
DEVELOPMENT AND CONSTRUCTION
(i) Step 1: First of all we have cut the icebox in one end so that it fits the heat sink.
Fig 11: Cut Icebox (14Lts)
(ii) Step 2: Than we have taken the Peltier module and pasted the heat sink on it using
ceramic paste.
Fig 12: Peltier module and heat sink

(iii) Step 3: Then we have inserted this combination (peltier module and heat radiator) to
the icebox. The wire terminals of the peltier module are kept outside the box.
Fig 13: Heat sink
(iv) Step 4: The wire terminals of the peltier module are then connected to the wires of the
fan and the fan is kept outside the icebox.
Fig 14: Connection between peltier module and fan

(v) Step 5: then this whole thing is connected to the two-way switch.
Fig 15: Connection of Two-way switch
(vi) Step 6: The two-way switch is further connected to the battery (12V) which is
charged using the solar cell panel.
Fig 16: Battery connected to Solar cell panel

(vii) Step 7: The aluminium sheet is fitted inside the icebox covering the peltier module.
Fig 17: Aluminium sheet
(viii) Step 8: The total assembly is shown below.
Fig 18: Complete Setup

5.1 DESIGN AND ANALYSIS
5.1.1 DESIGN
Firstly the part-modeling of different components of this project has been done in Pro-E and
3-D rendering done in Autodesk 3DS. Following are the simulated models of the respective
components:
Fig: Model of individual components

Fig19: Complete refrigerator model
5.1.2 CALCULATIONS/ANALYSIS
The calculations have been carried out using the necessary formula and putting the values of
temperature as recorded by a thermocouple temperature sensor.
COOLING CAPACITY
Volume of water to be cooled = 0.35 liters = 0.35 Kg
Ambient temperature (Th) = 27 ºC
Cooled temperature (Tc) = 5 ºC
Time required for the refrigerator to cool 0.35 liters of water = 40 minutes
Now, the cooling capacity required by the refrigerator to cool 0.35 liters of water in 40
minutes from 27 ºC to 5 ºC is equal to the amount of heat rejected by the refrigerator.
If ‘Q’ is the amount of heat rejected then,
Q = (m*c*dT)
Q = m*c*(Th-Tc)
m = mass of water to be refrigerated (Kg)
c = specific heat of water (J/Kg/ºC)
dT = temperature difference (ºC)

Q = 0.35*4180*(27-5) Joules
Q = 32186 Joules
So the heat rejected per second = (32186/3600) J/s
= 8.940 J/s
= 8.940 W
TOTAL POWER REQUIREMENT
The total power required by the refrigerator is equal to the sum of power required by the fan
and the power required by the peltier module.
Power used by the fan = 0.48 W
Power required for the peltier module = 60.8 W
So total power required = (60.8+0.48) W
= 61.28 W
CALCULATION OF Coefficient of Performance (COP)
The COP of the refrigerator is calculated as the ratio of heat removed to the power input or
the ratio of refrigerating effect to the work done.
So, COP = (Heat Removed/ Power Input) = (Refrigerating Effect/ Work done)
= (8.940/61.28) = 0.145
COP = 0.145 or 14.5%
Thus, the COP of this refrigerator is 14.5%.
SOLAR CELL PANEL CONFIGURATION
Each solar cell generates 1.8 Watts (0.5 V* 1.8 A) of electricity.
Here, the calculation is for the minimum number of solar cells required to drive the
refrigerator.
So, number of solar cells needed = (61.28/1.8)
= 34.04
= 35 (approx) units
Thus, the minimum number of solar cells required as according to the power input is
approximately equal to 35 units.

CHAPTER 6:
RESULT AND DISCUSSIONS
The Coefficient of Performance of the refrigerator is found to be 0.145 or 14.5% by
consuming only 61.28 watts of electricity while changing the cabinet temperature from 27 ºC
to 5 ºC. This shows that the refrigerator consumes less energy to give a considerable cooling
effect.
Here, the discussion is solely concentrated on the advantages of thermoelectric refrigeration
system and comparison of thermoelectric refrigeration system with other methods of
refrigeration.
6.1 ADVANTAGES OF THERMOELECTRIC REFRIGERATION SYSTEM
 COMPACT SIZE: The space required by the cooling system is very little.
 LIGHTWEIGHT: The unit is very portable which can be carried with one hand and
is unaffected by motion or tilting.
 LOW PRICE: 20% - 40% less expensive than compressor or absorption units.
 LOW BATTERY: The battery used is of low voltage, 12V.
 HEATING OPTION: This unit can also be used for heating operations.
 SAFETY: No toxic refrigerant or open flames, propane.
 RELIABILITY: Thermo-electrics provide a substantial degree of reliability of long
period.
 EASY SERVICE: The parts can be easily replaced by a screwdriver.
 LOW MAINTENANCE: This unit requires no maintenance at all due to absence of
moving parts.
6.2 COMPARISON OF THERMOELECTRIC REFRIGERATION WITH OTHER
METHODS OF REFRIGERATION
 THERMOELECTRIC: The process of cooling is obtained by the use of Peltier
modules which uses the Peltier effect.

 COMPRESSOR: Unlike closed cycles such as Vapor Compression Refrigeration
system, it does not need a compressor in order to produce cooling effect. It uses a
Peltier module attached with a heat sink.
 ABSORPTION: Unlike Vapor Absorption Refrigeration system, it does not need to
vaporize a refrigerant to produce cooling effect as it uses no refrigerant.
 COMPACTNESS: The thermoelectric modules the very compact because of the
small size of the cooling component.
 WEIGHT: The unit weighs 1/3rd
to ½ of the weight of other refrigerating system.
 PORTABILITY: These units are light enough to carry with one hand and are not
affected by tilting or motion whereas compressor models are quite heavy.
 COST: It costs 20%-40% less than other equivalent compressing or absorption units.
 INSTANT COOLING: The refrigerator achieves maximum cooling temperature in
about 30 seconds.
 RELIABILITY: Thermoelectric units do not wear out due to prolonged use as there
are no refrigerant or moving devices as compared to Vapor Compression or
Absorption units because of a tendency of leakage.
 MAINTENANCE: These units require low maintenance due to one moving part, fan,
and can be replaced with a screwdriver only whereas in both compressor and
absorption units, they require trained mechanics and special service equipments
needed for service.

CHAPTER 7
CONCLUSION AND FUTURE SCOPE
7.1 Conclusion
After the completion of the project it can be concluded that compressor less refrigeration is
possible and can be done using thermoelectric effect (Peltier effect). Using the peltier effect
not only refrigerators but heat pumps also can be made which will simultaneously heat and
cool substances. These compressor-less refrigerators are very cheap to manufacture, have less
number of moving parts, portable and can be used efficiently in hot weather.
7.2 Future scope
This project can be easily upgraded using more number of peltier unit, fan and by building its
body using terracotta clay or any other suitable substance which will further increase the
cooling inside the refrigerator. This will make the refrigeration effective and also increase its
COP. Since it is portable, lower priced, require low maintenance and the power source used
in this project is solar power, which is a renewable energy source we believe that its demand
is going to increase in future.

REFERENCES
Web References
1. http://en.wikipedia.org/wiki/Thermoelectric_cooling
2. https://www.ferrotec.com/technology/thermoelectric/
3. http://en.wikipedia.org/wiki/Mechanical_fan
4. http://www.nmbtc.com/ac-fans/accooling/
5. http://en.wikipedia.org/wiki/Heat_sink
6. http://en.wikipedia.org/wiki/Solar_panel
7. http://www.elecssol.com/solar-photovoltaic-36.html
8. http://en.wikipedia.org/wiki/Ice_box
9. http://dont-starve-game.wikia.com/wiki/Ice_Box
10. http://en.wikipedia.org/wiki/Battery_(electricity)
11. http://en.wikipedia.org/wiki/Wire
12. http://en.wikipedia.org/wiki/Switch
13. http://www.lightwiring.co.uk/two-way-switching-3-wire-system-new-harmonised-
cable-colours/
14. http://en.wikipedia.org/wiki/AC_adapter
15. http://en.wikipedia.org/wiki/Aluminium
References
[1] International Journal of Research in Advent Technology, Vol.3, No.1, January 2015E-
ISSN: 2321-963772 Thermoelectric Refrigeration by Using Solar Energy for Domestic
Appliance
[2] Xi Hongxia, Luo Lingai and Fraisse G., Development and applications of solar-based
thermoelectric technologies, Renew. Sustain. Ene. Res. 11(5), 923-936, (2007).
[3] Bansal P. K. and Martin A., Comparative study of vapour compression, thermoelectric
and absorption refrigerators, Int. J. Energy. Res. 24(2), 93-107, (2000).
[4] Dai Y. J., Wang R. Z. and Ni L., Experimental investigation and analysis on a
thermoelectric refrigerator driven by solar cells, . Solar ener. mater. solar cells 77(4), 377391,
(2003)
[5] Min Gao and Rowe D.M., Experimental evaluation of prototype thermoelectric domestic-
refrigerators, App. Ene., 83 (2), 133-152, (2006).
[6]Abdul-Wahab Sabah A., Elkamel Ali, Al- Damkhi Ali M., Al-Habsi Is’haq A., Al-
Rubai’ey’ Hilal S., Al-Battashi Abdulaziz K., Al-Tamimi Ali R., Al-Mamari Khamis H. and
Chutani Muhammad U., Design and experimental investigation of portable solar
thermoelectric refrigerator, Renew. Ene, 34 (1), 30-34, (2009)

AMRAR REPORT

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Viewers also liked

Viewers also liked (18)

Similar to AMRAR REPORT

Similar to AMRAR REPORT (20)

AMRAR REPORT