The document summarizes a student mini project on developing a thermoelectric air conditioning system. The system uses a thermoelectric Peltier module based on the Peltier effect to provide cooling without moving parts. It consists of a 12V Peltier device sandwiched between two heat sinks to dissipate heat, powered by a 12V battery. Fans are used to aid heat transfer. The document discusses thermoelectric principles, components used including specifications, assembly, advantages and limitations. The system was able to lower temperature by 2.11°C with a coefficient of performance of 0.8064 for cooling.

1. MINI PROJECT
THERMOELECTRIC AIR
CONDITIONING
SYSTEM
Div – U
Project Guide – Prof. Dr. J.P. Shete
Name Roll No. GR. No.
Shubham Lakhotia 26 141546
Keshav Kumar Jha 19 141569
Shreyas Saste 48 141480

2. INTRODUCTION
Thermoelectric effect (also known as peltier effect) is the direct
conversion of electric voltage to temperature differences and vice
verse. The direction of heat flow can be controlled by changing
the polarities of the voltage source.
• Thermoelectric cooling incorporates both semiconductors and electronic
assembly techniques.
• In a TEC (eg: Peltier device) one side gets hot and the other side gets
cold. Therefore, they can be used to either warm something up or cool
something down, depending on which side we use.
• Thermoelectric coolers (TEC) create a temperature differential on each
side.
• They are an excellent cooling alternative to vapor compression coolers for
systems that are sensitive to mechanical vibration.

3. OUR MODEL
Our project is a Thermoelectric Peltier Module. It is based on the
‘Peltier Effect’ (named after Jean Peltier).
Advantage of using such a device for the purpose of cooling is that it is
solid state (no moving parts), vibration free, noise-free. They are
modular devices, So are simple to install and operate.
Characteristics of the Peltier Module:
• Its ability to lower temperature below ambient.
• Heat transport controlled by current input.
• Compact size make them useful for applications where size or weight
is a constraint.
• Ability to alternate between heating and cooling.

5. Some Essential features
On an industrial level, this kind of a setup is used widely in
the field of Electronic, Medical, Aerospace,
Telecommunications.
For Cooling, this module is used in :
• Refrigerators
• Telecommunications equipment
• Laboratory instruments
• Electronic enclosures
• Temperature control in missiles and space systems

6. Some Essential features
The standard specifications for a thermoelectric module
are :
1.) The heat pumping capacity, or Qmax
in Watts
2.) The maximum achievable difference in temperature
between the hot and cold sides of the module, known
as the δTmax or ∆Tmax
3.) The maximum (optimal) input current in amps or
Imax
4.) The maximum input voltage or Vmax when the
current input is optimal (Imax ).
In mathematical formulae, temperatures are typically
expressed in Kelvin (K) units

7. COMPONENTS USED
Component Quantity Description Cost (Rs.)
Battery 1 12V, 7.5 Amp-hr -
Battery 6 9V 240
Peltier Device 1 12V, 6 Amp 450
Heat Sink 2 L Shape, Al 120
DC Fan 1 12V, 6.8 Watt 80
Epoxy 1 Araldite (90 g) 160
Thermocol 1 100 x 50 cm 60
Connecting
Wires
2 1 metre 30
SPDT Switch 1 - 12
Insulation Tape 1 Red 20
Glass Vessel 1 15 x 15 cm -
Extras - Blade, Glue, etc 100

8. Working Principles
Peltier Effect:
Jean Peltier discovered that the opposite was also possible.
By sending a current through 2 metals, you could create a
temperature difference in them.
Seebeck Effect (vice verse) :
In the 1820’s, Thomas Seebeck discovered that if 2 metals at
different temperatures were touching, an electric current
can be generated.

9. Peltier Effect
The Peltier effect is a
temperature difference
created by applying a
voltage between two
electrodes connected to a
sample of semiconductor
material.
The Peltier effect occurs whenever electrical current flows through
two dissimilar conductors. The flow of electricity causes one side to
get hot and the other to get cold. The degree of heating or cooling that
you get is determined in large part by the type of metal that is used.
Bismuth Telluride is a very commonly used Peltier element
metal.

10. Peltier Device
•When a voltage or DC current is applied to
two dissimilar conductors, a circuit can be
created that allows for continuous heat
transport between the conductor’s junctions.
•A typical Peltier module is composed of two
ceramic substrates sandwiching many pairs,
or "couples" of Bismuth Telluride dice. The
(pairs of) dice are connected electrically in
series, and thermally in parallel, between
the ceramics. One of these ceramics will be
the "hot-side" and the other, the "cold-side.“
For example, when n- and p-type semiconductors are biased in the same
direction, their charge carriers flow in opposite directions. As a result, n-
and p-type Peltier elements create opposite temperature gradients .

11. Peltier Device
Alumina ceramic substrates are commonly used for making TE
modules. They're ridged, thermally conductive and excellent electrical
insulators. In addition to providing a sturdy foundation, the ceramics
insulate the electrical elements within the module from a heat-sink on the
hot-side of the module, and the object being cooled on the cold-side
Heat transfer occurs in the direction of charge carrier movement.

12. Peltier Device Specifications
Type TEC1-12706
Dimensions 40 x 40 x 4mm
Couples 127
Qmax (Watts) 50
Delta Tmax (ºC) 66
Imax (Amps) 6.4
Vmax (Volts) 14.4
Module Resistance
(Ohms)
1.98
Fully sealed for protection against moisture

13. Basic Principles
• To increase heat transport, several P type or N type
thermoelectric(TE) components can be hooked up in
parallel.
• However, the device requires low voltage and
therefore, a large current which is too great to be
commercially practical.
• The current should always be DC and not AC.

14. Seebeck Effect
• The Seebeck effect is a phenomenon in which a temperature
difference between two dissimilar electrical conductors or
semiconductors produces a voltage difference between the two
substances.
The Seebeck Coefficient is given
by:
where  is the
electric field.
dxdT
x
/

 

15. Battery
• We have used a 12V rechargable lead acid battery with a current rating
of 7.5 Amp hours.
• Lead acid batteries provide a good amount of power and are compact.
They are widely used for storage in backup power supplies.
• Excessive charging of the lead acid battery Causes electrolysis, i.e.
Release of Hydrogen and O² gas. Accumulation of these gasses leads to
explosion of the Battery.

16. Heat Sink
• A heat sink is an electronic
device that incorporates either
a fan or a peltier device to keep
a hot component such as a
processor cool.
• There are two heat
sink types: Active and Passive.
• Heat Sink prevents a device
from overheating by absorbing
its heat and dissipating it into
the air.

17. HEAT SINK
• WHAT IS A HEAT SINK?
A heat sink is an environment or object that absorbs and
dissipates heat from another object using thermal contact. Heat
sinks are used in a wide range of applications wherever efficient
heat dissipation is required; major examples include refrigeration,
heat engines, cooling electronic devices and lasers.
Thermal resistance is defined as
temperature rise per unit of power,
analogous to electrical resistance,
and is expressed in units of degrees
Celsius per watt (°C/W).
We Have used an
L-Shape Heat Sink

18. HEAT SINK
• PRINCIPLE OF HEAT SINK:
Heat sinks function by efficiently transferring thermal energy from
an object at a relatively high temperature to a second object at a
lower temperature with a much greater heat capacity. This rapid
transfer of thermal energy quickly brings the first object into thermal
equilibrium with the second, lowering the temperature of the first
object, fulfilling the heat sink's role as a cooling device.
epoxy

19. HEAT SINK
• Performance:
Heat sink performance is a function of material,
geometry, and overall surface heat transfer coefficient.
Generally, forced convection heat sink thermal
performance is improved by increasing the thermal
conductivity of the heat sink materials,increasing the
surface area and by increasing the overall area heat
transfer coefficient .

20. HEAT SINK
• Construction and Materials:
A heat sink usually consists of a base with one or more flat surfaces
and an array of comb or fin-like protrusions to increase the heat
sink's surface area contacting the air, and thus increasing the heat
dissipation rate. Heat sinks are made from a good thermal
conductor such as copper or aluminum alloy. Copper (401 W/(m·K)
at 300 K) is significantly heavier and more expensive than aluminum
(237 W/(m·K) at 300 K) but is also roughly twice as efficient as a
thermal conductor.
Aluminum has the significant advantage that it can be easily formed
by extrusion, thus making complex cross-sections possible.

21. HEAT SINK
• Explanation:
In common use, a heat sink is a metal object brought into contact
with an electronic component's hot surface — though in most cases,
a thin thermal interface material mediates between the two
surfaces.
Microprocessors and power handling semiconductors are examples of
electronics that need a heat sink to reduce their temperature
through increased thermal mass and heat dissipation .

22. EPOXY
• Stabilizing and mounting of the DC fan and peltier on the Heat sink
was done using epoxy.
Characteristics –
• Stress Proof
• Heat proof
• Water proof
• Non-corrosive
• Non-Toxic
• Resistant to most chemicals.
• Araldite is used as a Standard Epoxy Adhesive.

23. CALCULATIONS
T cold = 35.8ºF = 2.11ºC
T hot = 115.7ºF = 46.5ºC
So,
COP cooling = Tc / (Th – Tc)
= 0.8064
COP heating = Th / (Th – Tc)
= 1.055
Where,
T cold – Minimum Temp. of
Peltier
T hot – Maximum Temp. of
Peltier
COP – Coefficient of
Performance (measure of
success of cooling/heating)

24. DC Fans
V = 12V
P = 6.8 Watts

25. Cooling Container
Material – Thermocol (Polystyrene Foam)
Dimensions = 248 x 235 x 285 mm
Thickness = 30 mm
We used Polystyrene Foam due to its high heat
and cold resisting property.

26. Advantages
• Thermoelectric modules have no moving parts and do not require the
use of chlorofluorocarbons. Therefore they are safe for the environment,
inherently reliable, and virtually maintenance free.
• A thermoelectric cooler permits lowering the temperature of an object
below ambient as well as stabilizing the temperature of objects above
ambient temperatures.

27. Advantages
• Ability to lower temperature below ambient.
• Heat transport controlled by current input.
• Able to operate in any orientation.
• Compact size make them useful for applications
where size or weight is a constraint.
• Ability to alternate between heating and cooling.
• Excellent cooling alternative to vapor compression
coolers for systems that are sensitive to mechanical
vibration.

28. Dis-Advantages
• Able to dissipate limited amount of heat flux.
• Lower coefficient of performance than vapor-compression
systems.
• Relegated to low heat flux applications.
• More total heat to remove than without a TEC.

29. Problems Faced
• We encountered a problem
with one of the dc fans so we
decided to dissipitate the
heat energy from hot side i.e
hot heat sinks we kept those
sinks in water bath.
• Firstly we used 12V lead acid
battery 1 AHr which didn’t
give a sufficient result of
what we have expected. So
we used a higher rating
battery from a motor bike.
• Stabilizing and mounting of
the DC fan and peltier on the
Heat sink was done using
epoxy

30. RECOMMENDATIONS
• When a laptop is running on batteries, the electricity
used to power the fan comes from the battery.
Therefore, to conserve battery life, a thermoelectric
power generator is a good alternative.
• We can insulate the surrounding areas of the peltier
device with thermofoam (or any other material with
high resistance to thermal energy) so as to avoid heat
dissipation into the surrounding atmosphere.
• We can use another peltier module at the bottom of
the apparatus and convert the heat liberated, into
electrical energy using Seebeck Effect.

31. References
• Goldsmid H. (1986). Electronic Refrigeration.London:Pion.
• Goldsmid H.(1964). Thermoelectric Refrigeration. New York:Plenum.
• Lasance, C.J.M., and Simmons, R.E. (2005) Advances In High-Performance Cooling For
Electronics. Electronics Cooling. Retrieved May2006. http://www.electronics-
cooling.com/html/2005_nov_article2.html
• Mollar(2003). Themoelectric Cooler Selection Procedure. Retieved June 2006.
http://www.marlow.com/TechnicalInfo/themoelectric_cooler_selection_p.htm
• Tellurex. (2002). The 12 Most Frequently Asked Questions About Themoelectric
Cooling. Retrieved May 2006. http://www.tellurex.com/12most.html
• TE Technology, Inc. (2005). Thermoelectric Modules. Retrieved April 2006.
http://www.tetech.com/modules/
• Wikipedia the Free Encyclopedia(May 2006). Semiconductor.. Retrieved May 2006.
http://en.wikipedia.org/wiki/Semiconductor.

32. THANK YOU