Eschew Obfuscation: Farting Along With Air Cars

Farting Along With Air Cars

Max Dunn — Fri, 07 Mar 2008 16:32:00 -0800

I was trying to explain to my wife how an air car worked, and with a smile on her face she said “So it farts as it moves forward?” Well maybe that sums it up nicely.

But do air cars really make sense? The information from the manufacturers seem like they are the solution to our energy crisis, and to everything else too [1]. But there are several fundamental problems with air cars.

"Farting Along With Air Cars" by avagadro

Thu, 19 Feb 2009 08:04:36 -0800

In their own test the air car traveled 7.22 KM., that is less that 5 miles. everything else that they claim is just words, not proven at all. They prey upon the public’s ignorance of science and their desire for alternative energy. Even their plan for many factories is inconsistent with economics, they plan to have factories producing 10,000 cars per year, that is 40 per work day. What ever happened to economies of scale, maximizing the use of capital resources etc? The more factories the more downpayments on factories they can accept, it all comes down to money. A thorough analysis of the entirety of their claims and press release reveals a company that will say and claim anything, proof is not something they provide.

"Farting Along With Air Cars" by G.J.

Sat, 04 Oct 2008 03:06:47 -0700

Regular servicing of compressors should be feesable to ensure a long life, just like your car now…..you don’t go more than 6 months without aat least an oil/filter change?? or coolant check what about your servicing of your vehicle? Or even servicing the air con compressor???

why should an compressor in your air car be any different…..

Here in Australia compressor manufacturers are looking at better, quieter and cheaper compressors that using solar energy can re-compress the used air and refill the cylinders. failing that a large tank of compressed air at your nearest fuel station just like the lpg gas should suffice

"Farting Along With Air Cars" by A.P.

Wed, 11 Jun 2008 13:41:03 -0700

How about giving a run down on the engine that runs on salt water?

"Farting Along With Air Cars" by J.R.

Sat, 08 Mar 2008 18:10:31 -0800

Yes, okay. I tried to find flaws in your logic or math, but alas I must accept that the compressor cost and time may be the Achilles heel of the air car concept. It will need to be replaced eventually, and that represents a cost similar to replacing batteries in an electric car. I still think it warrants further R&D investigation to find better ways of compressing air, but I don’t suppose it will be a viable choice for transportation in the near future. Darn! :-(

"Farting Along With Air Cars" by Max Dunn

Sat, 08 Mar 2008 11:47:49 -0800

Thanks for your comments J.R. It is always healthy to get critical feedback. :-)

In regards to battery cost, in a previous post, I calculated the battery cost of an electric vehicle to be about $0.08 per mile. If we figure that the air compressor will cost $8,000 and that it will last for 10,000 hours of use, then the compressor cost would be $0.12 per mile! (Assuming that every hour the compressor is running adds 6.67 miles worth of compressed air – 50 miles / 7.5 hours.)

Of course, the big unknown is how long the compressor will last. I tried to find this out by looking at used compressors and how many hours they had been run. The highest I could find for a 5000 psi compressor was only a couple of thousand hours. This doesn’t mean that they won’t last substantially longer, but it is hard imagining that they could go much past 10,000 hours.

Another disadvantage of a compressor is that they are loud. I don’t think I would want a compressor running all night in my garage!

"Farting Along With Air Cars" by J.R.

Sat, 08 Mar 2008 10:51:06 -0800

Thanks for the thorough analysis as usual Max. You list three problems with air cars, but I disagree that they are really disadvantages. First, the 50 mile range is more than enough for the average commute in America which is l6 miles (ABC News). Second, the inefficiency of storing energy as compressed air is more than offset by the savings over batteries. Unlike batteries, gas cylinders do not wear out, and since the battery replacement represents the vast majority of the per mile cost of driving an electric car, compressed air can be half as efficient (46% you mention vs. 80% for batteries) and still more be much more economical. Finally, perhaps we can be optimistic about the benefits of real R&D on compressed air cars – more efficient engines may be possible (hinted at in Tata PR – heating the gas), as well as better/cheaper compressors.

"Farting Along With Air Cars" by JJ

Fri, 07 Mar 2008 17:11:55 -0800

Hahahaha. I would like to get to talk to your wife. She sounds so witty! Hahaha. I can’t stop laughing. Anyway, I’d like to see how these cars will work. I get none of your technical terms but all sounds so interesting.