Peltier-seebeck effect allows thingies to be charged when one side of the thingy is warmer than the other. I believe there is many instances where this is true in cars. Hotter on inside than outside or vice versa. the energy generated from this effect could be used to further charge hybrid cars.
-- bob, Sep 06 2016

Exhaust Heat Recovery http://www1.eere.en.../deer10_meisner.pdf
[bs0u0155, Sep 06 2016]

BMW Turbosteamer https://en.wikipedi...g/wiki/Turbosteamer
[bs0u0155, Sep 06 2016]

This is a baked idea <link>. For car exhausts there are a few problems. There is certainly a decent heat gradient from the exhaust gasses to the general environment. The problem is the absolute temperatures are a bit nuts and variable for your garden variety peltier, 1000-2000C tends to count out most electronics. People have worked around it but the increased weight, cost and complexity usually obliterates any efficiency gains. BMW tried a steam system to feed power back to the crank <link>. From personal experience, anything exposed to the elements and the heat cycling of an exhaust system will break. Its a horrible environment.
-- bs0u0155, Sep 06 2016


... yet still somehow much more pleasant than Basingstoke.

Yes, what [bs] said - that sort of energy recovery is Baked and WKTE, generally on static or semi-static (marine) installations that run at more or less constant load.
-- 8th of 7, Sep 06 2016


Suppose the thingie* were attached to a large thermal mass, to dampen out the temperature variations, via a better insulator. The thingie then experiences steadier lower temperature over a longer time period with a longer operational life.

* technical term
-- whatrock, Sep 06 2016


I just wasted far too much time working out if I could make a thermoelectric addition to my motorcycle, I thought the air/oil cooling would allow a bit more temp difference, since the engines run 50-100C hotter. But no, turns out 12- 18W is optimistic. That might make a good phone charger.
-- bs0u0155, Sep 08 2016



random, halfbakery