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Old 03-26-2015, 07:22 PM   #9 (permalink)
serialk11r
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Quote:
Originally Posted by RedDevil View Post
The system that has the most chance of being effective would be one that employs the difference in coolant temperature to and from the radiator, never mind the exhaust.
It would reduce the effectiveness of the radiator, but then again it would also reduce the heat production of the engine.
Correct, coolant is the way to go. At 370K coolant vs. 600-1100K engine exhaust that's plenty of room to play with. You could have extra cooling systems like BMW and their Turbosteamer thing but that would cost a ton more money. A slightly bigger radiator from the factory doesn't add much cost, an extra radiator on the other hand just for the generator would be.

As for how much energy is in the exhaust, well at full throttle it's something like 40% heat energy going out the exhaust, at light throttle it's proportionally not much less but the temperature is lower so you can't collect as much. The TEGs nowadays can collect maybe like 2% of total fuel energy (adding to the ~30-35% engine efficiency) for modest single digit percentage improvement. That said, any load you take off the alternator counts extra because alternators are inefficient.
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