I have tried the experiment setup in the evening

A project log for Geothermal Energy Harvesting Garden Lights

use the natural, stable temperature of the ground to power garden lights and sensors via a thermoelectric device

trey-coreTrey Core 07/13/2018 at 19:360 Comments

I tried the setup with the ground radiator almost all the way into the ground. Then I placed the TEG on top of the ground radiator and then a PC CPU heat sink on top of the TEG. The test was done in the evening and I used a multimeter to measure voltage of the device. I did not produce any voltage.  I will try the test again in the day time so that the ambient air will be hotter.

Also of note is that I did not use any thermal paste on the device. I think thermal paste will be highly important to get decent performance from my setup.