Purpose: 

The objective of this lab is to explore the power generation potential of a thermoelectric “Seebeck” generator.

Principles: 

The thermoelectric effect: This is the conversion of temperature difference between two objects (cup of ice water vs. cup of boiling water) to electric voltage.A thermoelectric device is used in this process this temperature difference and in turn create voltage.

Seebeck Effect: The conversion of temperature directly into electricity

J = σ(-V+E_emf­­)

• σ is the local conductivity
• J is he current density
• V is the local voltage
• E_emf is the electric field of the electromotive force

The Peltier Effect:  Is the heating or cooling taking place at the thermoelectric device connected to two conductors; one in the cold cup, the other in the cup of boiling water.

Q = (x_b-x­_a)*I

• Q is the heat
• I is the current in amps
• X_b is the Peltier coefficient of material b
• X_a is the Peltier coefficient of material a

 

Ohms Law: States that the current through a conductor between two points is directly proportional to the potential difference across the two points.

V=I*R

• V is voltage
• I is current in amps
• R is resistance in ohms

Power: The rate at which energy is transferred, used, or transformed.

P=I*V,   P=I²R

• P is power in watts
• I is the current in amps
• R is the resistance in ohms
• V is the voltage in volts

Electrical Resistance:  The opposition to the passage of an electric current through a conductor. Resistance of the thermoelectric device is 1.5Ω

 Apparatus:

• Peltier Device (COM-10080)
• 2 Thermometers
• Heating elements
  • Boiling water
  • Cooling Elements
    • Ice & water mixture
    • Voltmeter

Procedure:

1. Setup the Peltier device and make note of the hot and cold sides of the device.
2. Measure the temperature of the room and record it below at “Start”
3. Measure the voltage the device is producing with the voltmeter, it should be roughly 0
4. Pour ice into the cup and fill the rest of it with water
5. Boil the water and add it to the second cup
6. Put the Peltier device into the cups with the hot side in the boiling water and the cold side in the ice water
7. Observe the voltage increase to its maximum value
   1. Record this value as the 0 time voltage
   2. Record the hot and cold temperature in the 0 time
   3. Repeat the measurements at the time intervals shown in the table below
   4. Calculate the current and power generated for each recorded time

10. Copy the results into excel and graph the voltage on the y-axis over the temperature difference on the x-axis

Data:

 

Analysis:

In our experiment, we found that the power generating potential of our thermoelectric generator was relatively low. This may be because the system itself is inefficient or because our experiment was performed on such a small scale. The principles implemented however, accurately explained the properties of the generator system. Because our experiment was performed on a very small scale, it would be interesting to determine whether increasing the sizes of both heating and cooling elements would generate more power. Also interesting to note is whether increasing the temperature of the heating element (making it hotter than boiling) would add to the voltage producing potential of the generator. This experiment showed that there a ways of creating electricity that produce drastically less harm on the environment. If research and resources were directed to making systems like our thermoelectric generator more efficient we just may find that we can reduce our dependency on fossil fuels. Overall, this course helped enhance our understanding of conventional energy producing methods as well as sustainable energy efforts. It also served to show that the possibility of living in a world that relies on sustainable energy instead of fossil fuels actually exists.

 

http://www.its.org/node/3767

http://www.howstuffworks.com/thermoelectricity-info.htm

http://en.wikipedia.org/wiki/Thermoelectric_effect