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September 28, 2007
Magnesium combustion engine
Technology Review: Solar-Powered Laser
A new kind of efficient, solar-powered laser has been developed by researchers at the Tokyo Institute of Technology, in Japan. They hope to use the laser to help them realize their goal of developing a magnesium combustion engine. The researchers described the new laser in a recent issue of Applied Physics Letters.
The idea, says Takashi Yabe, a professor of mechanical engineering and science at the Tokyo Institute, is to make a powerful laser capable of combusting the magnesium content of seawater. In the process, large amounts of heat and hydrogen are given off.
Magnesium has great potential as an energy source because it has an energy storage density about 10 times higher than that of hydrogen, says Yabe. It is also highly abundant, with about 1.3 grams found in every liter of seawater, or about 1,800 trillion metric tons in our oceans, he says.
Moreover, the magnesium oxide resulting from the reaction can be converted back into magnesium, says Yabe. The catch? Recycling the magnesium oxide back into magnesium requires temperatures of 4,000 kelvins (3,726 �C)--hence the need for a laser to generate such temperatures on a small spot.
But for a magnesium combustion engine to function as a practical source of energy, the lasers need to be powered by a renewable energy source, such as solar power.
Posted by Sun at September 28, 2007 04:06 AM