All that's left to do now is to hook up the generator
and make a shit-pot-full of peanut butter sandwiches.
Posted on 03/19/2007 4:47:16 PM PDT by HangnJudge
March 19, 2007 Many respected engineers have been trying for years to bring a compressed air car to market, believing strongly that compressed air can power a viable "zero pollution" car. Now the first commercial compressed air car is on the verge of production and beginning to attract a lot of attention, and with a recently signed partnership with Tata, India’s largest automotive manufacturer, the prospects of very cost-effective mass production are now a distinct possibility. The MiniC.A.T is a simple, light urban car, with a tubular chassis that is glued not welded and a body of fibreglass. The heart of the electronic and communication system on the car is a computer offering an array of information reports that extends well beyond the speed of the vehicle, and is built to integrate with external systems and almost anything you could dream of, starting with voice recognition, internet connectivity, GSM telephone connectivity, a GPS guidance system, fleet management systems, emergency systems, and of course every form of digital entertainment. The engine is fascinating, as is and the revolutionary electrical system that uses just one cable and so is the vehicle’s wireless control system. Microcontrollers are used in every device in the car, so one tiny radio transmitter sends instructions to the lights, indicators etc
Most importantly, it is incredibly cost-efficient to run – according to the designers, it costs less than one Euro per 100Km (about a tenth that of a petrol car). Its mileage is about double that of the most advanced electric car (200 to 300 km or 10 hours of driving), a factor which makes a perfect choice in cities where the 80% of motorists drive at less than 60Km. The car has a top speed of 68 mph.
(Excerpt) Read more at gizmag.com ...
OK, 300 bar is about 4300 psi, a bit more pressure than a standard SCUBA tank, IIRC. But how much volume, or how big a tank, would be required, I wonder.
It pains me that I can't do this in my head. But I'm an EE, not a Mech Eng. Wish I had paid more attention to those Fluids classes 40 years ago.
I've a colleague (North American) who has something like this. I just worry about the pressurized tank...
You should run for political office in Seattle. Your guaranteed to win with that attitude where all the lib their politicians believe we should get around in Fred Flintstone cars that you push with your feet.
Magnets, gravity power, solar assist, frictionless bearing, sound power! <----all non explosive!
No compressed air! really. :-)
These tanks hold 90 cubic metres of air compressed to 300 bars.
I can't do the math to get the tank size
Sure would be easier to compress (liquifies)
Not sure I'd want CO2 for my air conditioning however
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How is a frictionless car relevant in this context?
4400 psig? Don't reserve one for me.
Quite agreed. But I suspect few Americans have even heard of Tata.
Publius, you ignorant slut.
It's common to make reasonable simplifications in these kinds of back-of-the-envelope calculations. In this case omitting air resistance is reasonable since at 20 km/hr (which is what, 12 mph?) wind resistance would be small.
My main point was that you can't use a unit that expresses energy used for a given acceleration as though it were energy used for a given distance travelled. That's mixing apples and oranges.
A further criticism would be to point out that most driving that occurs at 20 km/hr is city driving and involves lots of speeding up and slowing down. When you account for those accelerations, you're going to see a lot more energy used.
It sounds as if you are lifting one kilogram (weight of 9.8 newtons) one meter in one second. This would be force x velocity, which is power.
But you aren't lifting mass generally in a car. On level ground and constant speed you are merely overcoming rolling friction and air resistance. So, the actual work done moving the car at a low constant speed is much less. You can't tell how much unless you measure the frictional losses.
Of course, acceleration requires much more work to be done each second.
http://science.slashdot.org/science/07/03/19/2128249.shtml
Ongoing discussion on SlashDot
Store Spent fuel at my place? put it in the Dry cask storge casks and you sure could. Half the price too. Send me 20
So, the actual work done moving the car at a low constant speed is much less.
Right, and if you omit friction and wind resistance then there's virtually no work being done, no energy being used.
Of course, acceleration requires much more work to be done each second.
Yep. I mentioned this in my post above.
Calculating Compressed Air Electricity Costs
In its publication, Improving Compressed Air System Performance: A Sourcebook for Industry, the U.S. Department of Energy (DOE) provides a simple formula to calculate annual electricity costs operating a compressed air system at full load.
Data Needed:
Check the compressor motor's nameplate for these ratings:
Brake horsepower (bhp) - this is the power available at full loads
Motor efficiency - this can also be estimated if not listed on the nameplate; DOE suggests 90 percent for new motors, 80 percent for older ones.
Annual hours of operation (hours per year)
Cost of electricity in dollars per kilowatt-hour ($/kWh). For current rates, check out the California Public Utilities Commission website under Energy, Rates and Tariffs.
Formula:
Annual electricity costs = (compressor bhp) x (0.746 kW/hp) x (motor efficiency) x (Annual hours of operation) x (Electricity cost in $/kWh)
Conversion Explanation:
"0.746" in the formula converts horsepower into kilowatts.
Example:
Imagine a 1000 hp system with 90 percent efficiency that operates 2080 hours annually and electricity rates of $0.10/kWh. The calculation would be -
1000 x 0.746 x 0.90 x 2080 x $0.10 = $139,651 per year in energy costs!
I understand, but then, what happens when all the air is let out, dont they go flat?
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