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Registered Member
Join Date: Mar 2006
Posts: 1,325
Country: United States
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some number crunching.
I was just about to post a new topic with the same title, and realized I should look back to see if I was being redundent...
according to my figures, a thermo electric generator from Hi-Z would cost around $8 per watt of generator, Solar (PV panals) cost around $4.50-$5 per watt, just as a comparison (but PV needs sunlight).
And I'm not sure on the life span of Thermo generators, altho they are a solid state generator, they are also subjected to alot of heat, and need cooling, so that puts alot of stress on them I would think.
I just sent an Emial to Hi-Z asking them about passenger car sized units, I'll see if I get a response.
How much energy can you get out of your exaust? those generators seem to peek out at 5% efficentcy, but your gas engine peeks at around 27%, and figur that maybe half that wasted energy is going out the tail pipe in the form of heat, and presher? so to make it simple, you have as much energy going out your tail pipe, and out your radiator, each, as your car produces (please, someone correct me if I'm way way off base here) but lets say my 92hp civic vx engine produces... on average 40hp while I'm driving around town, 5% recaburing efficenty of 40hp is 2hp of energy that could be capured in the form of electricity, something like 750 watts per horse power, so, if you were to recapture all of the heat going out your tail pipe, in theory you could get 1,500 watts of electricity... and you would have cold exaust of course, now you can not capure 100% of that heat, but then you also don't need 1,500 watts, sure your starter is around 1,200 watts, but it only runs for 3 seconds, your headlights are 65 watts each, you might have 6 indicator lights at 5 watts each, and 10 more at 1.5 watts, brake lights 25 watts each, of course other then headlights you can replace all your lights with LED's (head lights will be coming soon I'm sure) and cut 45-50 watts of that down to aorund 3-5 watts but then you have the ignition coil, fuel pump, radio, computer, so let say between 250, and 300 watts, will alow you to keep driving at night listening to the radio as long as you don't have a sub woofer.
so to get a thermo electric generator that would produce just that 300 watts it's going to cost around $2,500, you of course could suplement that a little with some PV to keep your battery charge in the day time sun, and that might be a good idea anyway as this kind of system wouldn't produce power for the first minute or so of the car running.
so I think you would be able to make something that would be able to compleatly replace your alternator and keep up with most reasonable electrical loads, however it's going to cost alot, more then I paid for my car I know for sure, and I still think it's a good idea, and I keep checking to see if the price has gone down, and it hasn't in the last 4 years.
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What I think is interesting is how you are able to use them in reverse - applying a current to a thermocouple can be used as a regrigeration device.
Linear Mode
