Can you show me how you make a thermocouple. I do understand what you're saying only that I would like something visual to make reference on so I know I'm doing it correctly.It's dirt easy. Solder or weld two wires of different metals together. Stick the soldered end into something that's hotter or colder then the other end of the two wires and that's enough so there is a minute voltage between the free ends.
Make a long zig zag of alternating wires between the two temperatures to multiply the voltage. This is called a thermopile. The Voltage is #&^#$ small, so unless you are planning a whole furry wire coat around something you are planning to get the thermal energy from, you will be able to run a quartz clock at best.