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The thermo electric effect

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The thermo electric effect

  1. 1. THE THERMO-ELECTRIC EFFECT By, Prajwal Keranahalli
  2. 2. WHAT IS IT?The thermoelectric effect is the direct conversion of temperature differences to electric voltage or vice-versa.The direction of heat flow can be controlled by changing polarity of the voltage source
  3. 3. HISTORYIn the 1820’s Thomas Seebeck (Germany) discovered that if two metals at different temperatures were touching you could create an electric currentJean Peltier discovered that the opposite was also true. By sending a current through two metals you could create differences in temperature
  4. 4. WHY DOES THIS EFFECT OCCUR?Charge Carrier Diffusion and Phonon Drag Seebeck Effect Peltier Effect
  6. 6. THE ZEROTH LAW OFTHERMODYNAMICSPairs of P and N type conductors are both it contact with a copper plate.There will thermo power until the system is at equilibrium. (All three materials are at the same temperature)
  7. 7. SEMICONDUCTORS Semiconductors have an electrical conductivity between materials like copper and glassThey possess and interesting property where its conductivity increases with added temperatureP and N type (thermocouples) semiconductors are created by doping.
  10. 10. APPLICATIONSThermoelectric generatorCooling ComputersDrink CoolersRecharging DevicesSpace ProbesSolar PowerClothingUseful, Quiet, no Moving PartsIt is less efficient (10%) and more expensive
  11. 11. TEST FOR UNDERSTANDINGThe USB Coffee cup warmer is an example of the Seebeck Effect or the Peltier Effect?Before the P and N type Semiconductors what material were used instead as thermal couples for thermoelectric modules?What are the advantages of using thermoelectric generators over, for example heat engines?
  12. 12. REFERENCESRockwood, Alan L. (1984). "Relationship of thermoelectricityto electronic entropy". Phys. Rev. A 30 (5): 2843–4. Bibcode1984PhRvA..30.2843R. doi:10.1103/PhysRevA.30.2843G. Jeffrey Snyder and Eric S. Toberer "ComplexThermoelectric Materials" Nature Materials 7, 105-114(2008).CRC Handbook of Thermoelectrics, Introduction, Edited byD.M. Rowe, CRC Press, 1995.G. Jeffrey Snyder, Tristan Ursell. "Thermoelectric efficiencyand compatibility" Physical Review Letters, Vol 91 p. 148301(2003)