Turbo-powered alternator

[serialk11r]

Yep, without active cooling they're worthless. With active cooling you might be able to get a few volts out of it, but the problem isn't the volts, it's the total power. 300C, 60mm TEGs push less than 20W with >200C delta.

We don't even need higher efficiency TEGs to be able to use them on cars actually, we just need higher temperature ones. They're not commercially available though, to the best of my knowledge. Allowing 500C rated TEGs to interface with exhaust would mean a pretty simple and compact unit using perhaps 6 of them could supply all of the car's electrical energy.

Higher efficiency ones would be good when mild-hybrids become standard.

[oil pan 4]

Originally Posted by silverinsight2

you need ~ 46 of them in series to get ~14vdc (14v/.3v=46 units)

I bet they are going to act like solar panels where you need at least 17 to 18 votls open current to be able to push any useable amount of power onto the vehicles electrical system.
On my truck I use 3 panels wired up for 21.5ocv, hooked to the batteries at14.3 volts they push almost 0.4 amps, it keeps the batteries fully charged.

"when operating well they read like .32-.35v"
Just like a single solar cell.

[serialk11r]

Okay I found some slightly more reasonably priced 300C TEGs that are 75 bucks: http://www.espressomilkcooler.com//P...-12611-6.0.pdf

Hopefully the government money that went to GM for developing waste heat recovery wasn't all wasted and they get something to the market soon.

[oil pan 4]

Originally Posted by serialk11r

Okay I found some slightly more reasonably priced 300C TEGs that are 75 bucks: http://www.espressomilkcooler.com//P...-12611-6.0.pdf

Hopefully the government money that went to GM for developing waste heat recovery wasn't all wasted and they get something to the market soon.

Knowing GM was likely wasted on something unfeasable or other wise uneconomical.

[serialk11r]

Yea
But I really hope someone makes skudderite 800-900K TEGs commercially available soon, they seem to have slightly better Z than most materials now, and something that can directly interface with exhaust more or less could be very effective. 1-2 pounds of TEG, a few more pounds worth of aluminum waterblock, a 2 pound radiator, hooked up to the existing cooling system, a DC-DC converter to prevent it from sapping power before the engine heats up, could easily provide almost all of the car's electrical requirements.

Oh and speaking of waste, I noticed that some of the companies doing TEGs were using a noble gas in a heat exchanger on the exhaust, rather than bolting the TEGs directly...what the hell? Did they do that to intentionally add weight and cost and make it seem unfeasible?

[serialk11r]

Just saying by the way, assuming electric supercharging systems haven't taken off by the time I get around to this, I intend to someday build a blowdown turbine for an NA engine connected to the crankshaft directly via speed reduction using a large twin scroll turbocharger and removing the compressor side. I'm thinking a GT47 or so geared down 9:1ish to a 2L engine. At 7000rpm or so it should hopefully make a healthy few horsepower, with some luck it could hit 10hp. It's okay that the turbine spins too slowly at lower rpm, since blowdown losses are lower at low rpm anyways.