Thermoelectric

To increase gas mileage, carmakers can use smaller engines that produce the same power from less fuel. But they can also work to recapture part of the 70 percent of fuel's energy content that internal combustion engines waste in producing heat, noise, and momentum that has to be halted via braking. Hybrid-electric systems that use regenerative braking and excess engine power to charge a high-voltage battery pack--think Toyota Prius--are one way to recapture wasted energy. New focus on heat energy But another method that's gaining attention is to recover lost heat energy, as in the...