COLLEGE PARK, Md., June 9, 2011 /PRNewswire-USNewswire/ -- No one is happy about rising gas prices, and to make matters worse, up to 60 percent of each $4 gallon is wasted, lost as heat that pours out of the exhaust pipe. But what if some of that heat could be collected and converted back into electricity that can recharge the battery that powers the lights, wipers, power steering, or even the electric motor in a hybrid vehicle? The technology to do just that exists, but it's still a work in progress. The solution lies in thermoelectric devices, and engineers at the A. James Clark School of Engineering, University of Maryland, are challenging previous assumptions about the behavior of the nanoscale materials used to build them. Create better materials, they say, and cars will make much better use of that expensive fossil fuel. But contrary to the common assumption in nanotechnology, "better" in this case may not always mean "smaller." That realization may change the way engineers develop future thermoelectric devices. A material whose response to a change in temperature generates electric potential, or vice versa, exhibits what is known as the thermoelectric effect. Thermoelectric devices can generate electricity when heated by an external source, or quickly cool or heat their environment when powered with electricity. So why doesn't every car have a thermoelectric power generator? "The reason thermoelectric devices have so far been limited to niche markets is that their efficiency is still too low," explains graduate student Jane Cornett (Department of Materials Science and Engineering). "The goal of our work is to design thermoelectric materials that convert energy from one form to another more efficiently so we can promote the widespread use of products that recycle waste heat and effectively reduce our consumption of fossil fuels." For example, cars manufactured or retrofitted with a thermoelectric device placed around the exhaust pipe can use waste heat to generate electricity, improving their overall miles per gallon, especially when a power-draining system like the air conditioning is in use. If the device is too bulky and inefficient, however, it will consume more energy than it contributes.