Another hope in 'green' springs out from the laboratory of Ohio State University and Caltech. A new thermoelectric material which could help to make fuel engines more efficient. And the researchers behind the innovation say that with some more development, their material could have a 10% percent effect on a car's fuel efficiency. A significant saving individually and collectively in times when the crude barrel prices are spiraling upwards.

A small refresher on thermoelectricity -

Thermoelectricity is a physical phenomenon where a temperature differences create an electric potential which can be used to generate electricity. The thermoelectric effect can directly convert temperature differences to electric voltage and vice versa.



In a car, only about 25 percent of the energy produced by a typical gasoline engine is used to move the vehicle or run accessories like the radio or windshield wipers. Much of the rest escapes through the exhaust pipe as heat and smoke. If this heat could be recaptured and converted into electricity, it could lead to fuel savings. This basic and simple idea has been behind many previous works on applying the thermoelectric principles to internal combustion engines. But hitherto low fuel prices negated the initial costs of usage of such devices. But it seems rising fuel prices now could bring a hidden windfall for the green movement if such devices get incorporated in modern vehicles.

Jeff Snyder from Caltech, one of the researchers who worked on the project says,” Now that energy costs have gone up by a factor of five, these alternative ideas that have been around for awhile are a lot more viable." Snyder further said that if made on a large scale it might be possible to develop the systems for $10 a unit or less. The cost would be a determinant for it to be accepted for widespread use.

Currently, thermoelectric power generators use an alloy called sodium-doped lead telluride (Na-PbTe), which has a rating of 0.71, a thermoelectric figure of merit. In an experiment, team of researchers led by Dr. Joseph Heremans at Ohio State University used a new element - thallium, to increase this rating to 1.5. The new material was subjected to high temperature tests to validate its thermoelectric properties. At 230 degrees Celsius, the material converted heat to electricity with the same efficiency as currently used materials. Its efficiency increased as the temperature went up and at 500 degrees Celsius it hit its peak efficiency rating of 1.5. The temperature ranges use in the experiment are the ranges normally found in today's power systems like car engines and generators.

The only minus seems to be the element Thallium. Thallium is a toxic substance and a carcinogen. Though widely used in the electronics, pharmaceutical and the glass manufacturing industries, a viable non-toxic element for motors should be a better solution. The researchers as stated are working precisely towards that end.
Source: Environmental News Network

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