PROJECT
REPORT ON
Solar
ThermoElectric Coolers
(Peltier Cooler)
BLOCK DIAGRAM
PELTIER EFFECT
Electric Current
Difference in
F between
Materials A and B
Material A
Material B
Heat
Absorbed or
Expelled
PELTIER EFFECT
In 1834, a French watchmaker
and part time physicist, Jean
Peltier found that an electrical
current would produce a
temperature gradient at the
junction of two dissimilar metal.
When the current direction was
reversed, the cold junction would
get hot while the hot junction
would get cold.
CAUSE OF PELTIER EFFECT
When a current flows across the junction of two
metals, it gives rise to an absorption or liberation
of heat, depending on the direction of the current.
i.e. Applying a current (e- carriers) transports heat
from the warmer junction to the cooler junction.
As an example of the Peltier effect, consider the circuit shown here.
Under these conditions, it is observed, as indicated in the diagram,
that the right-hand junction is heated. It shows, in other words,
that electrical energy is being transformed into heat energy.
Meanwhile, heat energy is transformed into electrical energy at the
left junction, thereby causing it to be cooled. When the current is
reversed, heat is absorbed at the right junction and produced at the
left one.
The rate of evolution of or absorption of heat is
proportional to the current & thus the peltier effect is
reversible.
If direction of current is changed then the peltier effect is
also reversed.
The energy absorbed or evolved at one of the junctions of
the two dissimilar metals when one ampere of current
flows for one second is called Peltier coefficient ,denoted by
BASIC PRINCIPLES
WHAT ARE SOME APPLICATIONS?
Cooling:
Electronic enclosures
Laser diodes
Laboratory instruments
Temperature baths
Refrigerators
Telecommunications equipment
Temperature control in missiles and space systems
Heat transport ranges vary from a few milliwatts to
several thousand watts, however, since the efficiency
of TE devices are low, smaller heat transfer
applications are more practical.
WHY ARE TE COOLERS USED
FOR COOLING?
No moving parts make them very reliable;
approximately 105 hrs of operation at 100 degrees
Celsius, longer for lower temps (Goldsmid,1986).
Ideal when precise temperature control is required.
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.
DISADVANTAGES
Able
to dissipate limited amount of heat
flux.
Lower coefficient of performance than vaporcompression systems.
Relegated to low heat flux applications.
More total heat to remove than without a
TEC.
KEY
COMPONENTS
USED :
1. TEC1-12706 Heatsink Thermoelectric Cooler
Cooling Peltier Plate Module 12V 60W.
They consist primarily of
semiconductor material
sandwiched between ceramic
plates and have no moving parts
Model : TEC1-12706 -Size:
40mm x 40mm x 4mm -Operates
from 0~15.2V DC and 0~6A
-Operates Temperature: -30 to
70 -Max power consumption:
60 Watts -Original box: NO -Net
weight: 22g -Package weight:
31g
Thermoelectric Module
2. CPU Cooling Fan
Material: Alumunium,
Plastic
Colour: Black Silver
Dimension: 6.5 Cms x 9
Cms x 7 Cms
Compatible device: All
PC, Laptops and CCTV
camera's
3. DC Power Supply
4. Solar Panel
5. Control Switch
COMPARISON OF THERMOELECTRIC REFRIGERATION and
OTHERMETHODS OF REFRIGERATION
THERMOELECTRIC:Cooling is achieved electronically using the "Peltier"
effect - heat is pumped with electrical energy.
COMPRESSOR :Cooling is achieved by vaporising a refrigerant (such as
freon) inside the refrigerator - heat is absorbed by the refrigerant through
the principle of the "latent heat of vaporisation" and released outside the
refrigerator where the vapour is condensed and compressed into a liquid
again. Uses mechanical energy.
ABSORPTION:Cooling is achieved by vaporising a refrigerant (ammonia
gas) inside the refrigerator by "boiling" it out of a water ammonia solution
with a heat source (electric or propane). Uses the principle of "latent heat of
vaporisation". The vapour is condensed and re-absorbed by the ammonia
solution outside the refrigerator. Uses heat energy. s.
COMPARISON OF THE FEATURES OF ALL THREE SYSTEMS:
COMPACTNESS:Thermoelectric Cooler are the most compact because of the
small size of the cooling components - cooling module / heat sink / cold sink.
WEIGHT:Thermoelectric Cooler units weigh 1/3 to 1/2 as much as the other
units because of the lightweight cooling system - no heavy compressor.
PORTABILITY:Thermoelectric Coolers are the most portable because they are
light enough to carry with one hand and are not affected by motion or tilting.
Compressor models are quite heavy and the absorption models must be kept level
within 2 - 3 degrees.
PRICE:Thermoelectric coolers cost 20% - 40% less than the equivalent sized
compressor or absorption units available for recreational use.
BATTERY DRAIN:Thermoelectric Cooler have a maximum current drain on
12 volts of 4.5 amps. Compressor portables draw slightly more current when
running but may average slightly less depending on thermostatic control
settings. Absorption portables draw 6.5 to 7.5 amps when running and may
average about 5 amps draw.
Project Progress
PROJECT REPORT BY :1. SANTOSH KR. SINGH
2. SHASHWAT RAWAT
3. SHUBHAM SINGH
4. MOHD. SAQUIB
5. AMAN SINGH
MENTOR:MR. MAHENDRA SINGH TOMAR
(ASSISTANT PROFESSOR)
MECHANICAL ENGG. DEPARTMENT
