TEG (Thermal Electric Generators)

About 165,000 results for TEG for sale, so, yes.

...although one needs to be wary of those peddling over-unity generators. Oh, and snake oil.

Reducing the exhuast temperature using some form of economiser, and a TEG used in this way qualifies as one, runs the risk of lowering the final exhaust temperature below the dewpoint of sulphuric acid, at which point the exhaust system components become more susceptible to corrosive attack. The returns can diminish below the point where fitting and using it can prove a complete waste of money.

I am an expert on TEGs and they are called thermoelectric generators. They can be used to generate power, but efficiency is low, so you need a good deal of heat. If you want say, 20W, you need 400W watts of heat, going through the module at 5% efficency which is typical. Check Hi-Z incorporated or custom thermoelectric.

You can also get prepackeged modules with heat sink and electronics assembeled. The electroncis is just DC-DC converter.

p.s. Sorry for the spelling mistakes, i am using my phone..

Heat in exhaust gas could be used for thermal-refrigeration/air conditioning of the vehicle. Or else similar to turbo charger exhaust gas could be used to drive a variable speed generator whose power could be used to charge vehicle battery or refrigeration/ air conditioning.

How?

A lot of work has been done on this in IIT Bombay, India. In fact a refrigerated truck was demonstrated. But it was not based on thermoelectric generation but "Carbon Ammonia Adsorption" using exhaust gases of truck.

Since Ammonia was used, I think there were no takers for the technology, may be due to safety concerns

I have used several, but always in the reverse direction. That is: sending a current through the device in the direction that makes it essentially a heat pump, transferring heat energy from a cool side to a warmer side.

Most, if not all of the beverage/food coolers that will plug into the 12V automotive connection use ThermoElectric devices (aka Peltier effect devices), commonly with a fan to help get rid of the heat.

There is no feasibility for your specific idea, because there is no benefit to generating, storing and transporting electrical energy around in a typical vehicle. Of course, in an electric vehicle, you do not have an IC heat source. I suppose you could trry to harvest the battery coolant for your idea.

Along those lines, let's say that you have a hybrid vehicle like a Chevy Volt, that could effectively reduce IC engine run time by extending battery life through an additional TEG generator that was powered by the exhaust of the IC engine. The ratio of energy demand by the vehicle, versus the potential energy supplied by the TEG, is infitesimal. It certainly is technically feasable. Take the TEG cost, plus the weight penalty, plus the space penalty, plus the increased maintenance, plus reduced reliability/increased complexity penalty over the value of the energy, but more importantly, over the usefulness, of the energy. Energy produced but not used to replace purchased energy has no value.

The refrigeration truck idea is interesting, and it is not obvious to me that ammonia is dangerous, or at least more dangerous, in this application, than other refrigerants. Is that really true?

I have to ask this obvious question. why would you install a complex item with additional wiring, piping, to a motor vehicle underside or in a very cramped engine bay, when on the engine is a perfectly good and efficient alternator and compressor.

Rather impractical, like putting solar panels on a submarine.