Thursday, November 8, 2007

Vive Innovation!

A car that runs on air is described on the International Herald Tribune. More info at Green Car Congress. I love the apparent simplicity of the French design and it is still a "plug-in" vehicle. Granted, 120-mile range and top speed of 68 mph for a small vehicle may not be impressive, but it all goes back to a mindset of what is the most common usage of the vehicle, rather than the exceptional case of the 200-500 mile trip. NEV's get some attention because they are designed for the most common case in urban areas, and this sort of vehicle could fit the same solution, and uses the same power source - the grid. I wonder though, is there a greater efficiency in keeping the energy stored as "mechanical" energy, rather than repeated conversions from stored energy to elecricity to stored electrical energy to mechanical energy and back to stored electrical energy in the case of regenerative braking. At many points along that chain there is a bit of heat generated and wasted. The waste heat at the generating station, batteries get hot during charge (and need to be cooled), the motors get hot, etc.

This reminds me of the UPS hydraulic regenerative braking system I read about some time ago. The idea was that braking in a delivery vehicle would recapture a portion of the energy used to move the vehicle, which could then be used to drive the wheels when the vehicle was restarted.

And more recently, articles about using compressed air energy storage to store wind energy (or any other generated form of energy, really) when electricity demands don't require the power and then releasing the stored pressure to drive turbines to generate electricity during higher demand and low wind periods.

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