Fossil Fuels

Published on June 13th, 2014 | by Nicholas Brown


GMZ TEG Module Successfully Generates 200W From Engine Heat

June 13th, 2014 by  

GMZ has successfully tested a thermoelectric generator (TEG) that converts the heat from automotive engine exhaust systems to electricity. It even exceeded its target generation capacity of 200 watts. This unit can save fuel by reducing the load on vehicle alternators. Reducing the amount of electricity drawn from the alternator actually reduces the mechanical burden on the engine because the alternator becomes easier to turn. This saves fuel and reduces overall emissions.

Thermoelectric device diagram. Image Credit: Designua/Shutterstock.

Thermoelectric module diagram. Image Credit: Designua/Shutterstock.

The 200-watt module is part of a larger 1,000-watt generator set (for diesel engines) that GMZ is developing for the $1.5 million US Army–sponsored TARDEC (Tank Automotive Research, Development and Engineering Center) program which is administered by the DOE.

As the release on BusinessWire said:

The 200W TEG is a modular component of a larger 1,000W TEG that GMZ Energy is developing for the $1.5 million TARDEC program. Combining a module approach with a scalable thermoelectric heat exchanger design, GMZ Energy will integrate multiple 200W blocks into a single 1,000W diesel engine waste heat recovery solution. The TARDEC TEG incorporates GMZ Energy’s TG8-1.0 thermoelectric modules, which are the first commercially available, off-the-shelf modules capable of operating with continuous hot-side temperatures up to 600°C while at power densities greater than one Watt/cm².

This design could help the US Army because the cost of fuel transportation on the battlefield can amount to a startling $40 per gallon. The Army will first test this TEG in a Bradley Fighting Vehicle.

How It Works

Thermoelectric modules are solid-state semiconductor devices that generate electricity using a temperature difference. Heating one side of a thermoelectric generator while cooling the other creates a temperature difference which results in and drives the flow of heat through the module.

This flow of heat creates a potential difference (voltage). That potential difference causes it to generate electricity. This is called the Seebeck effect (discovered by Thomas Johann Seebeck). The key to operating a thermoelectric module efficiently (relatively speaking) is to maintain the greatest possible temperature difference between the two sides of it.

What Can You Do With 200 Watts?

200 watts can:

  • recharge hybrid-electric vehicle battery packs to extend range;
  • power dashboard fans;
  • power stereo systems;
  • power both tail lamps and headlamps.

This technology has long been criticized (and harshly) due to its poor efficiency, but it has proven itself to be useful due to the fact that engine heat would otherwise go to waste without the unit.

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About the Author

writes on CleanTechnica, Gas2, Kleef&Co, and Green Building Elements. He has a keen interest in physics-intensive topics such as electricity generation, refrigeration and air conditioning technology, energy storage, and geography. His website is:

  • Wayne Williamson

    I wish the article would have stated the size of the 200 watt module. Is it 10cm on a side or 1m or somewhere in between. As other posters have mentioned, this could have big applications to any power generation facility.

    Ok, I see Matt has it figured it at 4cm x 8cm based on the 1watt per cm2 mentioned.

    So just for fun lets say you have a cube 10 meters on a side or 1k x 1k x 1k cm something that can produce 1GW.

    This is way better than I had hoped for which was 250MW.

    • Wayne Williamson

      Just realized I posted this on cleantechnica, This is really what is needed for space exploration….
      Of course it could work with any high temp power generator.

      • Wayne Williamson

        Also realizing that this post is old, but on rethinking, my math is flawed. What I showed was 1g for volume, and it is more like 6m for surface…..1k x 1k x 6sides.

  • UncleB

    Nuclear cooling towers a new source of electricity?

  • UncleB

    geothermal to electric without a turning shaft, maintenance free?

  • UncleB

    Now add in a Fresnel lens for some home made Solar power . . .

  • sambar

    Is the process reversible? That is, can applying a current offer an efficient cooling device? Air-con for electric cars?

  • Paul Maher

    Hey, That’s pretty good, but I think there is a much greater benefit being overlooked. There are lots of ways to make heat that would very much like a way to turn that heat into electricity.
    Condensed Matter Nuclear Science has shown us a bunch of ways to do it. LENR, Thermophotovoltaics and Photoswitching are but a few. If that’s to far out for you consider the large arrays of reflectors that they are heating molten salts with to make steam. This is pretty good stuff, but let’s not get hung up on mundane uses.

  • eveee

    We don’t know the capacity of the converter or its efficiency and cost. In the ideal case, it would supplant the alternator entirely.

  • Matt

    “operating with continuous hot-side temperatures up to 600°C while at power densities greater than one Watt/cm².” So 200W would be 20cmX10cm (say 8in by 4 in) which is not that big. You have more than that pre-catalytic converter. And you CC is very hot so (ignoring cost data) could power most (all?) the electric needs of your ICE. If you have a hybrid then adds a bit to your range.

  • Ronald Brakels

    I was very impressed when I saw the 200 watts figure, then I read it was for a tank. And even though they appear to plan to get 5 times that amount from a tank, I think the average tank goes through more than 5 times as much fuel as the average car. (Although the lower efficiency of petrol compared to diesel makes up for it to an extent.) Still, this is good news that could see plenty of applications on anything that gets hot from laptops to air conditioner units to solar power systems. Or not. But we’ll see.

    • Bob_Wallace

      Abrams M1 tank? 0.6 MPG. Burns 10 gallons an hour while idling.

      • Ronald Brakels

        They should wind the windows down instead of running the air conditioner all the time.

        • Bob_Wallace

          What? And spoil the aerodynamics?

          • Ronald Brakels

            No, it totally works for in town driving. On the highway it’s better to shut the windows and use the AC. Mind you, if you wind down the windows on your tank when it’s 45 degrees Celcius you are going to be hit with a malstrom of hot air that will feel like a hurricane make of blow torch flames. A guy I knew tried to drive his tank across the Nullabour Plain (Null abour = Latin for no trees) with his windows wound down and by the time he stopped at the first service station he was cooked all the way through. And I swear to you, this story is not true.

          • UncleB

            Love the “assumption” that all tanks are for desert warfare. Canada’s Arctic oil now in jeopardy now that Prime Minister Harper went all “NATO” on Russia. What about tanks to defend that border?

          • Ronald Brakels

            Defend the border? You just let them in and after a while in arctic Canada they’ll probably pay you if you help them leave.

          • jeffhre

            Their AC units will require far less complicated logistical and supply line support!

      • Jan Veselý

        You just remined me an A.Lovins’ story from Winning the oil endgame. The RMI team purchased 5 kW diesel generator and put it on the outside of the tanks’ armour. It was used as an APU and tank didn’t need to run its 1500 kW gas turbine to make few kW to run AC, electronics and servos. It effectively reduced consumption by 40%.

  • JamesWimberley

    Do they really have dashboard fans and stereo systems in US Army tanks?

    • Offgridman

      Can you imagine driving around in a diesel powered metal box that didn’t have ventilation? And while no guarantees on the stereo it would be a sure bet that there’s at least one radio in each of them

      • jeffhre


    • Bob_Wallace

      Air conditioning. (It’s part of the chemical weapon defense system.)

      • heinbloed

        …. very suitable in the War For Oil. Propably Saving a lot on Diesel.

    • johnBas5

      In desert in the Iraq temperature can be very hot!

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