Air Power

Rarely do internet searches disappoint. But yesterday, I was disappointed twice by two related searches. I overheard two colleagues of mine talking about a vehicle, car if you will, that can transverse the continental US on a single tank of compressed air. This turned up nothing. Perhaps they were sharing a joke and I was naïve to the punchline. Ahh well. At any result, I did find an air-powered car that reportedly can travel 185 miles.

This relates back to a previous post I made about the nature of energy. Vehicles are particularly tricky because of what I called the discrepancy in space (i.e. they need to be portable). A windmill or a nuclear reactor are hardly portable, are they. And countless alternatives fail to meet the demands (battery powered car?).

I’m also a big fan of bicycles. Not that I’m much of a star on a bike, but I love the fact that it has long evolved as an efficient way to get energy out of humans. So, I was really excited to read in Wired magazine about an air-powered bicycle with a picture of what I thought was one. Again an internet search of air-powered bicycle didn’t get me to what I thought was a bike driven by human generated air-power. But rather, like the car, one charged by more conventional means.

Why I am disappointed about this. Well, energy and power are not the same. Energy is conserved, not power. We humans can’t produce a whole lot of power, but energy we get a lot of, some more than we need. We tend not to use the kilocalories we store up as soon as we’d like. In fact, FDA says you take in 2000 calories (kcal) a day. With a good workout, you can expend a quarter of that, or about 0.6 kilowatt-hours. So, the instructables site let me down with my future air powered bike. But poking around that sight I also saw someone state how it’d be impossible to charge a 2HP air tank. That’s just not true. One person may not be able to create that much power. But that’s the great thing, we don’t store power, we store energy! Air is an untapped storage media of excess energy.

Sooo, the bike I wanted to see (which I guess I’ll have to design someday) uses your pedaling to store energy in the bike and outputs to the wheels when you want and at what rate (i.e. what power).