When Heat and Energy Collides

While everybody else is concerned about the rampant flooding that has been happening globally, it seems the never-ending quest to solve energy crisis is here to stay and stay for long. We are running the risk of exhausting fossil fuel reserves and different science and technology institutions are working hard to look for an answer for this problem. Scientists are banking heavily on properties of thermoelectric materials, which is of great importance for their practical application. This material turns heat into electricity more efficiently than anything available today.

It has been found that thermoelectric materials can be used for the development and utilization of new cooling methods. This improvement can help eradicate the use of greenhouse gas. The researchers are optimistic about thermoelectric materials in the group of clathrates, which create crystals full of ‘nano-cages’. Thermal conductivity of the nano-cages can be reduced if a heavy atom is placed inside those cages.

Recent advances using nanotechnology, however, have revived this moribund field, and have car makers such as General Motors and BMW taking notice, hoping to increase fuel efficiency and eventually replace alternators and possibly even internal combustion engines with thermoelectric generators (source: Free Power for Cars, Kevin Bullis).

According to General Motors senior analyst Francis Stablers, as much as 70 percent of the fuel energy burned up in car engines doesn't go toward moving the vehicle along or powering the CD player. Instead, it's dissipated as waste heat. Stabler says a new generation of thermoelectric materials can convert heat to electricity well enough to be used for taking the burden of electricity generation off the engine, thereby saving fuel. Researchers still need to find ways to make these materials cheaply and consistently, however, before they can be widely deployed. But certain niche uses could help the technology get established (source: Free Power for Cars, Kevin Bullis).

Thermoelectric materials are more environmentally friendly and can be used to build up vehicles that are more fuel-efficient. Thermoelectric materials have exceptional unique properties; these materials can be assembled into units, which can convert the thermal difference into electrical energy or vice versa – electrical current to cooling.

For efficient use, the material should supply a high voltage and have good electrical conductivity. But the thermal conductivity of the material should be low. This low thermal conductivity is very important because it will lessen the “electrical” wear and tear of a device. Car manufacturers are finding the thermoelectric materials very attractive for the conversion of wasted heat into electrical energy (source: Alternative Energy article, 2008).

In summary, if the majority of heat coming from vehicles is wasted, by using thermoelectric materials, it can turn into a very useful tool in developing power. This material transforms heat into electricity by using the difference in temperature across the different sides of a device. If we attach a thermoelectric device into a car’s exhaust pipe, it can produce electricity which can be used for driving the car or charging a battery.

If the technology proves to be reliable, Stabler says, it could eventually replace alternators altogether and run electrical water and oil pumps, relieving the extra work for the engine, boosting performance, and saving fuel. John Fairbanks, technology development manager at the U.S. Department of Energy, suggests that if all GM cars alone used this technology, it would save roughly 100 million gallons of gas per year (source: Free Power for Cars, Kevin Bullis).