[couple google board searches yeilded discussion on all this semi recently cant say i like rewarding laziness with posting a story like this...]
Hi,
First of all I'm new to the board.
While i am waiting for extra harddrive magnets to make a generator for a windturbine, I got an idea: Would it be possible to use heat to make electricity? I know a shop that sells cheap fresnel lenses (book/page magnifiers). Using a couple of lenses like this and the sun, you can make a realy hot spot (~300-500°C?).
The 2 options that came in my mind to turn the heat into electricity were:
- Thermocouples (don't know about the spelling); I remembered them from school (it's 2 wires of different metal twisted over eachother I believe): they give of some electricity when they are heated on one end but they had vey low efficienty. (maybe one can overcome this by making lots of them and packing them together?)
- Steam: use the heat to boil water and get the steam to power a (homebrew) steamengine and a generator. The downside would be that I constantly would need to fill the reservoir with fresh water.
Another option would be to aim the lenses at a PV-cell and hereby increasing it's efficienty, but i would like to keep this project low-cost and i don't have PV-cells yet.
If anyone else knows other (better) options, please share them. 
What would be the best choice or is the entire project a bad idea to start with?
Thx in advance,
The Crazy Noob.
