In a world that tries to save more and more of its resources, BMW wants to make use of the car’s heat to recover some of the energy lost by thermal means. It’s just that they understood this time by being green means putting a radioactive thermoelectric generator in the car’s tailpipe.
The thermoelectric device generates electricity when heated. Volkswagen also has an ongoing research on this, but BMW says they will recover up to 5% of the fuel consumption of an Efficient Dynamics vehicle.
BMW’s project is called “Megacity Vehicles”, and it’s scheduled to be on market in about 5 years. That much time means a lot, since battery and fuel cell technologies advance every year with dozens of inventions.
I don’t know if the big brother’s BMW approach is the healthiest, but their conservative trend towards inventing new patches for old bugs resembles a bit with Ford’s denial of advancing from the model T some decades ago. Though, BMW’s cars are extraordinary.
Would this be some kind of policy of keeping a certain kind of customers motivated, by showing off with fuel savings of 5%? I like fast and powerful cars, I also like renewable energy, but… let’s be serious: I wouldn’t think of putting a radioactive thing in my tailpipe, even if it were folded in ten layers of lead. I don’t think that’s doing any good to the environment, since in the case of an accident… you don’t know where that material will end up.
But… who am I to judge?
There is NOTHING RADIOACTIVE in the BMW device. The article has it completely wrong. The BMW device uses only a thermoelectric converter to make electricity from waste heat. The heat comes from the engine. In deep space applications the source of heat is a radioactive material, but NOT in a car or any consumer product.
Chalk it up to bad writing; the writer really should have used a conjunction to contrast those two sentences. David is correct: all the thermoelectric needs is a source of heat coming in and a method to dump it out. Radioactive isotopes and thermoelectrics work well in space because they are a solid state system that can last as long as the isotope decays. HOWEVER, here on earth where oxygen is readily available we can use the exhaust from the combustion engine as a source of heat, and dump it back into the cooling loop. From the picture in the article, I’d say that is what BMW is doing. The article really could have used a “however” or a “whereas” between those two sentences.
I doubt very much that the BMW work uses a radioactive device to generate the power: it would be too dangerous. Far more likely to be using the thermoelectric/Peltier effect: see sites such as
http://en.wikipedia.org/wiki/Thermoelectric_effect
for background, and therefore am concerned that in your headline you misrepresent the activities of BMW and Volkswagen.
The system VW proposes is different of BMW’s. Here’s a quote from Car Magazine: “Thermoelectric generators – or TEGs – convert heat differences between radioactive metals to generate electricity. With car engines expending a high percentage of their energy in the form of heat, BMW has hooked up a TEG to a prototype’s exhaust system to generate around 200W of power. ‘Some of the heat generated by combustion is converted to electric energy which is then fed back into the car’s power supply to feed high-demand systems such as climate controls,’ Draeger told CAR Online.”.