Air Car- runs on compressed air and/or combustion

[ERD50]

More back-of-the-envelope calcs:
Which brings up another question--why will plug-in electric cars be so much cheaper to run? I'm guessing that it's because the conversion from gasoline to mechanical energy is less efficient (in small motors) than the conversion from electricity--> chemical PE (battery)-> electricity --> mechanical energy. Plus some gains from regenerative braking (in city driving).

That's it.

Internal combustion engine - Wikipedia, the free encyclopedia

Most steel engines have a thermodynamic limit of 37%. Even when aided with turbochargers and stock efficiency aids, most engines retain an average efficiency of about 20%.[7][8]

Batteries and motors are pretty efficient. Charging a battery can be > 90%, maybe less on discharge, brushless electric motors > 85%.

Pretty big delta from 20% ICE

-ERD50

 

[Rustic23]

Another thing not mentioned. How does this thing do in traffic? i.e. What happens to the AC when stuck on a Houston freeway going 0 mph?

We live in a golf community. Most folks have a second vechile.... a golf cart!

DallasGuy... when I did go to work, it seemed I saw a lot of Beamers and such on both sides of me. While I don't deny that some folks are going to go for this, I don't think it will be enough to make a big dent. Americans tend to like their creature comforts. Also, in Texas, at least Houston, Everybody is for mass transit..... so the other guy will use it and get off my freeway!

 

[samclem]

To follow up on this:

This would be a very good application for solar power. The big problems with solar today are the intermittent nature of sunlight and the high cost of making electricity from the sun (the cost is coming down, but the dollars/watt still makes sense only in very expensive electric markets and with government subsidies).

BUT, converting sunlight into mechanical energy skips the expensive PV step. A collector/tracker and a heat engine capable of utilizing low-grade heat (e.g a Stirling cycle motor) could directly compress air at your home while the sun was out. When you get home, you've got a tank of compressed air ready to "refuel" your car. And, the intermittent nature of sunlight is no problem--if the day was cloudy, just plug in the electric compressor instead.

More rough estimates:

A Stirling cycle motor converts heat to mechanical energy with an efficiency of 15-30% (Stirling engine - Wikipedia, the free encyclopedia )

We already found out that it takes approx 20,240 kwh of energy to fill the compressed air tank. Sunlight gives 1000 watts/sq meter on a cloudless day. So, if we had a practical size tracking dish (say about 2 meters diameter= 3.1 sq meters) it would receive 3100 watts when the sun is out. If the Stirling Cycle unit converts it to mechanical energy at 22% efficiency, we are getting 680 watts worth of "compression work." At this rate, it will take 30 hours of sunlight per day to recharge our car's air tank if it is entirely empty.

So--If the sun has been shining and you've got a collector this size, you'd be able to refill 1/3rd of the compressed air in your car (10 hours of sun). That's approx 250 miles of driving IF you've also been burning gasoline in the car (getting 100+ MPG). If you need to refill more than 1/3rd of the air or it has been cloudy, you'll need to plug the car in at home to refill the air tank.

 

[alvarezg]

As I understand it, the material for the air tanks (there are 3) was chosen because its failure mode is to rip more or less gradually without throwing shrapnel all over the place.
The question that isn't answered anywhere is if those tanks are good for the life of the car or if they have to be replaced at some point because of fatigue.