Hi! I've made another MSPaint diagram, this time it looks even sillier and it's not on scale :)
The generator I've indicated for this application might be an overkill choice, but I'm sure there is a way to hook it up to a LED lightning system, using charge regulator. The pavement will work both as a heatsink as a water storage unit, so the water entering the generator will never be hot.
Right now it's an overpriced solution, but I'm sure the cost of each components will drop if more and more people start to buy them.
You can find the TEG components here http://www.tegmart.com/water-cooled/ and here http://www.tegmart.com/regulators/ http://www.tegmart.com/thermoelectric-module-acces...
or you could buy the chinese one http://www.thermonamic.com/TEG-HL100-English.pdf
for the floor I think that a water hose and aluminium sheets will do the job
I've also made two youtube videos about seebeck cells!!!! one in italian
and one in (sorta)english
thanks again for the attention, ciao