I am working on a solar oven powered thermopile and am trying to figure out how big to make the individual thermocouples. The easiest materials for me to get a hold of will be iron and nickel, Which will give me a seebeck coefficient difference of about 34, so I will need quite a few of these. How does the size of the metals used change the volts/amperes? How does a junction of two one inch-diameter bars differ from a junction of wires? O haven't found anything online that talks about this yet, and would love a pointer in the right direction. Also, I am planning on using a parabolic solar oven to do the heating work. My design is a stack: ceramic tile, thermopile, ceramic pile, piped water cooled by an evaporation apparatus, a heat sink, then a shade structure on top covered in the same reflective surface as the dish to keep the sun from baking the heat sink. If any one has suggestions on that aspect of the design, I am all ears. I am basing the stack off of this design:http://www.tegpower.com/index.html, though I added the water cooling to it. I am unsure how to get my hands on actual semiconductors, thus my iron and nickel plan. With all of this I hope to run a small fm radio while the sun is out, so I will only need around 9 volts. I am going off the assumption I can connect thermo couples in series/parallel as I could with dc batteries to attain the required voltage, is that correct?