Thermoelectric Power TEP

1
Thermoelectric Power (TEP)
Introduction The thermoelectricity was discovered
in 1821 by Thomas Seebeck where a continuously
flowing current was created when two wires of
different materials were joined together and
heated at one end. This is known as the Seebeck
effect (Fig.1). The Seebeck effect has two main
applications i.e. temperature measurement and
power generation. Seebeck circuit also creates
the refrigeration. This is known as Peltier
effect. When current passes from material A to
material B, the junction becomes either cooled or
heated (Fig.2). This forms the basis of the
thermoelectric Power.
Fig.1
Principle Thermoelectric modules can also be used
as thermocouples for measuring temperature or
providing the temperature- sensing element in a
thermostat. When one end is heated a current will
flow continuously. Then the current ceases and
voltage is measured by a voltmeter (Fig.3). The
voltage generated is a function of the
temperature difference and the materials of the
two wires used. Two wires used to measure
temperature in this manner form a thermocouple.We
define the Seebeck coefficient as Where
?Vdifferential voltage between the two ends of
the sample ?Ttemperature difference
between the two ends
Fig.2
Fig.3

• Instrument
• Figure 4. shows the schematic diagram of our
  instrument. The sample is on the sample space
  inside the OXFORD Chamber. We accurately measure
  ?V and ?T from two Nanovoltmeters, pass the
  current to heater for transport of thermal energy
  to the sample. In temperature controller, we fix
  the needle value by ITC503 and cooling the sample
  by water refrigerating compresser system which
  provides closed circuit helium gas compression.
  We use software (LABVIEW) to operate all the
  Systems.The TEP of Pb is
• Shown in Fig.5.

Fig.4
Fig.5