For a car that runs on gasoline, just one third of each gallon of fuel actually powers its systems. The rest, turned into heat, is wasted. However, new applications of thermoelectric (TE) power may allow automobiles with internal combustion engines to be built to run more efficiently. Transforming some of this unused heat into electrical energy could help power everything from lights and windows of passenger cars to hydraulics and electric doors of construction vehicles.
Published in the Energy Quarterly section of the June 2013 issue of the Materials Research Society (MRS) Bulletin, Philip Ball's Thermoelectric heat recovery could boost auto fuel economy begins by acknowledging that, because electric vehicles that run on batteries "remain a distant prospect for routine use, especially for long-haul heavy transport and construction machinery," internal combustion engines will likely stick with us for a while--along with their inefficiencies and pollution.
TE generators would help put the fossil fuel to better use, by converting some of the wasted thermal energy to electrical energy. Fuel efficiency would also improve with TE generators taking some of the alternators' electricity-generating responsibilities. NASA has shown TE conversion efficiencies up to 15% in high temperature gradients. If similar efficiencies can be achieved in automobiles, turning 5-10% of a vehicle's wasted heat into electricity could mean a 3-6% reduction in fuel consumption.
Creating electrical energy from thermal energy isn't easy. Since only a little electric energy is generated by a lot of thermal energy, increasing the coupling of heat and electrical transport is critical to making TE power practical beyond unique applications like spacecraft. The difficulty of making automotive engineering work with these TE modules, as well as the high cost of the materials needed are also challenges for researchers developing this technology. However, as Ball writes, according to the lead researcher at IAV in Berlin, Daniel Jänsch, “Legislation, especially in Europe, is a driving force, and manufacturers could decide to implement more expensive technologies instead of paying carbon-emissions penalties." Jänsch also states, if TE systems reach their potential, thermoelectric power could be deployed in passenger cars as early as 2020.
via: Cambridge University Press
image CC BY-SA 2.0 by Richard Masoner / Cyclelicious