thermoelectric generator

Jason M. Hendler said:

Sounds like a solid state approach, similar to the Rankine cycle approach Honda is testing:

Link

1/3 of the energy created in combustion goes out the tail pipe and radiator, so capturing any / all that heat for other uses is a good idea.

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Thanks. Here it is, Honda Rankine Cycle -click 1/3? And the rest. Having ancillaries all electric, then this would be feasible if sized properly. But it gets complicated. BMW claimed 20% better fuel consumption, by elimination of parasitic engine loses.

So if this Rankine unit was coupled to say the Lotus range extender. more mpg would be had.

Absorption a/c units can run off waste exhaust heat. I believe Cadillac were using one.

srmarti said:

I remember seeing articles on thermoelectric generators on the Chevy Suburban exhaust could provide 1 mpg and 800 watts at highway speeds. No mention of cost though. Searching around the web, it looks pretty expensive to add to the vehicle; maybe on the order of $10 per watt.

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The efficiency is dire. That is why a small Stirling or Rankine unit is better to turn an alternator.

There is a small heating boiler used for boats run off diesel. BMW put this in their 4x4s and large cars. It is 80% efficiency. So it is used to heat up the engine and the car. When idling to warm up, the engine is about 15% efficient, so big savings in this respect. It can be remotely switched on with the heater fan and small electric pump as well. The engine is warmed up, the screen de-iced and the cab warm. It can be used normally, even in summer, giving a quick warm up as it sends hot water directly to the cylinder head to get the choke off quicker, eliminate glow plugs, and heater is hot quicker if needed, then it cuts out.

It does improve overall mpg significantly. How much? Depends on your climate.

BMW have done a lot to tweak around the edges to claw back. They are behind in EVs, etc, that's why.

http://green.autoblog.com/2008/02/18/honda-testing-rankine-cycle-hybrid-to-recapture-energy/
Honda Rankine exhaust heat -click
Looking at this, it gets complicated and big. To the point you may as well dispense with the IC engine and Rankine unit and install a full external combustion Stirling unit - another unit ideal as a range extender, or even a small compact steam cell engine.

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wtiger said:

You should be able to get a descent output from a thermal electric generator from the tailpipe. A 150hp car should produce several Kw of peak power from a well designed TEG. From what I understook one of the big drawbacks is the cost.

I found this while looking around for numbers. It looks like it could be very promising for making such a setup cost effective

http://www.physorg.com/news186409698.html

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Depending on size, the cost will come down as they always do, it may be worth having a large version of this heated only by a small diesel oil burner to make electricity. All Solved!!

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