Gyrobob
Serious Thumper
Offline
Posers ain't motorcyclists
Posts: 2571
Newnan, GA
Gender:
|
Charon ses: There may be some confusion between "efficiency" and "cost." Efficiency is defined as the percentage of the input energy you get back in useful output. Cost and efficiency are not always directly related.
Compressed air for vehicles presents the problem of recharging. Low-pressure air, say up to 150 psi, is easy to find. High-pressure air, such as the cited 4000 psi, isn't so easy. Using the old marine rule of one-third for the voyage out, one-third for the return, and one-third for the unexpected you can only travel one-third of your maximum range away from home unless you have a known recharge location. You can carry a compressor, but something has to power it. Way back when I briefly tried SCUBA diving, the club's little gas-powered compressor took about half an hour to charge a single SCUBA tank to 3000 psi.
Using solar cells to charge an air tank sounds attractive. Solar cells produce electricity, which in turn will have to drive a motor to drive a compressor to charge the air tank. It can be made to work, but it will probably be less efficient than simply charging a battery bank.
Cost and efficiency are always related in one way or another. Sometimes the correlation is positive. Other times it costs a lot to build something with good efficiency.
Yes, creating an infrastructure with easily available 4000psi air is a challenge,.. much the same as finding places to recharge your plug-in hybrid in Macon.
The solar cells in my back yard charging a buried air tank would be less expensive to buy and operate than a wall of batteries. You could have a pretty small electric motor driving a pretty small compressor if the system was putting air in the tank every day during the day. The air tank would last forever,.. trying to do the same thing with a wall of batteries would cost a lot more to install, and would require battery replacement every several years, most likely. If I were going to have plug-in hybrid cars, instead of having a $15,000 wall of exotic batteries I had to buy, install, maintain, and periodically replace, I would have the system set up so I sold my solar panel electricity to the grid, and then drew on that account to recharge my plug-in hybrid from a wall socket,.... in effect forcing the utility company to store my energy for me.
|