From Exhaust to Energy

I was reading the Star Tribune over breakfast today when my dad pointed out this article. It was in the business section, which I never read, so if he hadn't mentioned it I never would've found it. I usually don't have much interest in the business type stuff but this article was very interesting. 

Apparently BMW (I just found out that the company is German) is testing vehicles with thermoelectric generators  to capture heat from the exhaust and turn it into energy. I think that is a really good idea because according so some estimates almost 60% of the potential energy in the gasoline burned by a car is let off as heat. 

This works due to the Seebeck effect, an process named after Thomas Johann Seebeck, a physicist who discovered that if he joined two different metals together with two junctions and created a temperature difference at the junctures, a nearby compass needle would be deflected. This is because the two different metals reacted differently to the temperature thus creating a current which created a magnetic field. At the time Seebeck didn't realize there was an electric current involved so he called the phenomenon the thermomagnetic effect. Hans Christian Orsted played a vital role in conceiving and explaining thermoelectricity (he is best known for discovering the relationship between electricity and magnetism called electromagnetism). 

However, though thermoelectric generators (thermogenerators) are relatively simple and low maintenance, they aren't very efficient. In car engines they convert about 6 to 8 percent of the heat into electricity.  But the lead researcher on this project, Rainer Richter, is convinced that new materials will make the generators much more efficient. 

There are also more places besides cars where this technology is or could be used. In the 1950s people placed thermogenerators over kerosene lamps to power radios. That same technique could be used to generate electricity from stoves or fires in developing parts of the world today. Thermogenerators could also be placed near chimneys, factories, smoke stacks and all sorts of places that give off heat. 

I think it could be a very useful invention once it is made more efficient. It would definitely be a good idea to make car engines more efficient but another good place to put them would be lawnmowers. Those engines are even worse than cars, probably 80% of the fuel is lost as heat. 

Facts of Germany

• The largest Wind Farm and Solar Power Capacity is installed in Germany
• In 2007 14% of the country's electricity was generated through renewable means
• It is one of the most populous countries in the European Union with over 82 million inhabitants but has the lowest fertility rate in the world with 1.39 children per mother
• The average life expectancy was estimated in 2005 to be 78.65, males 75.61, and females 81.81