perfidy

There's been a lot of reports lately about replacements for the venerable, if disappointing, battery. Battery technology has been around for centuries - milennia if you believe the Bagdad Battery is really a battery - but has always suffered from several key flaws as a store of energy. One, it's not a very dense store of energy. Two, it usually contains noxious, acidic, toxic (or all of the above) substances. They're heavy, and often fragile. And they have a goofy name. Several avenues have been investigated - fuel cells, capacitors, and now micro-miniaturized gas turbines. Fuel cells are nifty, I guess. The capacitor idea being developed at MIT has some cool nanotechnology. But this new idea from MIT just has cool written all over its tiny, silicon body.

A gas turbine has several essential components. A compressor, a combustion chamber, and a turbine to generate electricity. Gas turbines have been used for decades, but they range from table top to ship power plant in size. Until now, no one has come close to developing one that is smaller than a quarter. Using the same techniques as chip manufacturers, the researchers at MIT have created the components of their turbine on silicon wafers. Six of these wafers are stacked and bonded together to form a complete engine.

he MIT team has now used this process to make all the components needed for their engine, and each part works. Inside a tiny combustion chamber, fuel and air quickly mix and burn at the melting point of steel. Turbine blades, made of low-defect, high-strength microfabricated materials, spin at 20,000 revolutions per second -- 100 times faster than those in jet engines. A mini-generator produces 10 watts of power. A little compressor raises the pressure of air in preparation for combustion. And cooling (always a challenge in hot microdevices) appears manageable by sending the compression air around the outside of the combustor.

All of the components work, but the team has yet to get it all to work at once. They hope to have a working prototype in operation by Christmas.

If successful, this would be fantastically cool, and useful. If one of these babies can in fact run for ten times as long as a battery of the same weight, that's a major improvement. But the real improvement would lie in the refueling. If these turbines can be refueled rather than recharged, well instead of having to replace whole batteries, a small can of JP5 could recharge anything that runs on electricity. A major drawback of batteries is the lack of interchangeability. My cell phone, iPod, laptop, flashlight, radio controlled car, and wireless mouse all take different types of batteries. If a can of jet fuel looking just like a can of zippo lighter fluid could recharge any battery no matter the size, then you've got a real weight savings. In the military, this would eliminate a severe logistical problem for combat troops. For the average joe, it would be convenient as well, if not a matter of life or death.

Convenience, power, flammable substances, and tiny fan blades whirring at 20,000 rpm. What's not to like?