Michael B said:
Hey, I remember a story about an air-powered vehicle,
but It doesn't seem to have shown up in the Auto-X prize finals.
Anybody have any ideas about how it's doing nowadays?
In the embodiment of the "Aircar" the idea of an air-powered vehicle has all of
the earmarks of a persistent investment scam. For about a decade now, their
vehicles have been due on the road "next year".
The fact is that air is not a great vehicle for energy storage.
First, there are the laws of gas thermodynamics to complicate things. When you
compress a gas, it gets hot. That heat represents waste energy. Further; when
you expand a gas, it gets cold, which keeps it from properly expanding, which
means that you do not retrieve all of your stored energy. You can add
complexity to your compressors and air engines to reduce the thermodynamic
losses, but that adds weight, bulk, and cost.
Second; storing energy as a compressed gas takes heavy, bulky, and expensive
tanks. Even then, today's batteries probably give you better storage density.
Third; making an efficient air motor is not as simple as you may think. It
takes several stages of expansion to efficiently extract the energy from high
pressure compressed gas. Again, multiple stage engines add bulk, weight, and
cost.
One potential advantage of an air-powered vehicle might be quick recharging
compared to a battery vehicle.
Vaughn