Week Nine

During Week 9 of the project, the replacement thermoelectric cells arrived, and the group completed the final testing of the cell on the laptop.  The cell was applied to the computer with all of the precautions taken to ensure the best possible efficiency based on the tests and results of the previous weeks. 

Applying a thin layer of thermal paste to the cell.

Cell applied to the computer heat source, and paste added for the heat sink.

Heat sink placed on cell.

Tests were then completed in the same manner as before.

The tests resulted in a maximum voltage of 0.33 Volts, and a current of 28 milliamps.  Although better results were expected, these final tests achieved the best results seen on the computer, and will most likely be the best results possible with the materials and procedure of this project. 

This voltage will not be great enough to power the fan or any component of the computer, however it may be able to power a small incandescent light bulb.  This may be done simply to prove the concept of the thermoelectric converting applied heat to an electric current. 

There are many possible causes for the inefficiency of the cell, still including a temperature gradient across the cell that is not great enough.  This is most likely due to an inefficient transfer of heat from the computer, and also due to the cold side of the cell not being kept cold enough.

For the sake of experimentation, the group configured the cell in the opposite direction of use: a 9 volt battery was connected to the cell.

Configuring the cell achieved an impressive temperature gradient across the cell: one side was very hot and one side was very cold.  However, eventually the cold side of the cell heated up.  This probably points to poor insulation in and around the cell that makes the hot side transfer heat to the cold side, thus lessening the temperature gradient. 

           

This adds another possible cause of error for the project:  Inefficiency was also caused by poor insulation of the hot and cold sides.  The thermoelectric cell itself was also just not as efficient as expected in generating a voltage from heat.  A source to keep the cold side cold would make this particular cell function better, however this was not available in this project’s setup.