What can you do with 200 watts? You can power your headlights and tail lights, run your stereo or help recharge your hybrid battery to increase range. If that energy is free because it comes from engine heat that would otherwise go to waste, that’s power your alternator doesn’t have to generate, which saves some fuel. Free is good, right?
The US Army certainly thinks so. It will combine five 200 watt modular units from GMZ Energy to recapture 1000 watts from the diesel engines heat of its Bradley Fighting Vehicles. That may not sound like a big deal until you realize that under battlefield conditions, a gallon of gasoline can cost the equivalent of $400.00 or more, and that the U.S. military is one of the biggest energy consumers in the world.
How does a thermo-electric generator (TEG) work? It utilizes the Seebeck Effect to create a voltage between the very hot side of the unit mounted directly to the engine block and the cooler side away from the engine. The larger the difference in temperature between the two sides, the greater the flow of electricity generated. TEG’s have not had a very good reputation recently, but thanks to $1.5 million dollars in research and development funds provided by the TARDEC (US Army Tank Automotive Research, Development and Engineering Center), GMZ has succeeded in making its TEG’s meet the 200 watt per unit target set by the military.
According to Business Wire, the GMZ units are “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.” Recapturing waste heat is becoming a hot topic in motor racing these days. (No pun intended.) It is only a matter of time before this technology trickles down to the cars and trucks we use for daily driving.