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The Pressurized Air Car?

Discussions of conventional and alternative energy production technologies.

Re: Why is the Air Car not a viable replacement for fossil f

Unread postby yesplease » Wed 13 Feb 2008, 15:43:43

JRP3 wrote:Common? Try and order a Zilla 1K controller, it's a 6 month wait because the guy hand assembles them. Electric traction motors and controllers are not made on anywhere near the scale of automotive components, not even close.
Of course they are. If you want the brand new fancy crap you may have to wait, but with a little ingenuity it's easy to find suitable motors/controllers, and even used batteries on the cheap. There is no point in comparing used conversions to new vehicles, if we're talking about comparing a new BEV city car to a new air powered city car, it's a total strawman. MDI says it'll be less than $6,000 for a five seat city car. Show me a similar sized new BEV for a similar price, if you want to compare the two.
JRP3 wrote:Yes the used glider has depreciated, but all additional EV components are purchased at retail in small quantities. So for the sake of argument increase the cost of the glider and decrease the costs of all EV parts through direct volume purchasing and it balances out.
Could be, show me. Where's the cost of the components compared to the cost of the assembled electric drivetrain?
JRP3 wrote:Here's an example of markup. At work we get our batteries from a distributer, they get the battery from the manufacturer. We sell a battery for $75.00, we paid $40.00, the distributer probably paid $20.00. A mass manufacturer of EV's could bypass the middlemen and really cut costs on all components.
Could be. Show me there is that much markup in the deepcycle battery market and I'll be convinced.
JRP3 wrote:An 08 Aveo retails for $10,000. What do you think the glider version of that actually costs to make? Probably half that, and it's still a larger and nicer vehicle than the Aircar. GM could easily build an EV version for $10k but the limited range would be a hard sell for most of the public.
No way no how 50% of the Aveo's cost is in the drivetrain. Maybe a few grand at most, but considering Tata is set to sell the nano with a CVT and .624L engine for $2,500, stating that GM pays $5,000 for the Aveo's drivetrain doesn't pass muster. If you have proof, show me.
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Re: Why is the Air Car not a viable replacement for fossil f

Unread postby yesplease » Wed 13 Feb 2008, 15:49:21

I've shown that w/o a substantial drop in battery costs, or increase in electricity prices, there's no way an EV will be cheaper to power per mile than a compressed air vehicle.

If you contend that an EV will cost so much less to make, or that batteries will cost less, show me a similar EV set to come out with half the price of the OneCAT, or where I can batteries from a distributor in bulk that'll last 800 cycles and cost half or a third of what's sold over the counter. I'd love that last one fer sure. Group buy all the way! :-D
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Re: Why is the Air Car not a viable replacement for fossil f

Unread postby JRP3 » Wed 13 Feb 2008, 18:06:05

yesplease wrote:I've shown that w/o a substantial drop in battery costs, or increase in electricity prices, there's no way an EV will be cheaper to power per mile than a compressed air vehicle.

No you have not. You have speculated based on what MDI has claimed, not any real world aircar data since there is none. How can you claim otherwise? Let's look at the link you provided:
The OneCAT will be a five-seater with a glass fibre body, weighing just 350kg and could cost just over £2,500.
Note, "could cost".
A 350 kg car is a golf cart. Here's an equivalent "EV" for $4000.00, leaving you $1000.00 for extra batteries:
Cart
If you contend that an EV will cost so much less to make, or that batteries will cost less, show me a similar EV set to come out with half the price of the OneCAT

No, why don't you show me an actual air car with actual data that is for sale at an actual price? You keep asking for proof yet provide none for the air car.
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Re: Why is the Air Car not a viable replacement for fossil f

Unread postby JRP3 » Wed 13 Feb 2008, 18:12:58

yesplease wrote:
JRP3 wrote:An 08 Aveo retails for $10,000. What do you think the glider version of that actually costs to make? Probably half that, and it's still a larger and nicer vehicle than the Aircar. GM could easily build an EV version for $10k but the limited range would be a hard sell for most of the public.
No way no how 50% of the Aveo's cost is in the drivetrain. Maybe a few grand at most, but considering Tata is set to sell the nano with a CVT and .624L engine for $2,500, stating that GM pays $5,000 for the Aveo's drivetrain doesn't pass muster. If you have proof, show me.

Wow. I said an Aveo retails for 10k, not that it costs 10 k to build it, and that half the build cost is in the drivetrain, including engine, trans, exhaust, catalyst, computer, cooling, fuel tank, etc. Not to mention that Tata's nano is probably a piece of crap death trap, not a crash tested Aveo.
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Re: Why is the Air Car not a viable replacement for fossil f

Unread postby yesplease » Wed 13 Feb 2008, 18:39:09

JRP3 wrote:
yesplease wrote:I've shown that w/o a substantial drop in battery costs, or increase in electricity prices, there's no way an EV will be cheaper to power per mile than a compressed air vehicle.
No you have not. You have speculated based on what MDI has claimed, not any real world aircar data since there is none.
I have not speculated on what MDI has claimed, I have speculated on what WisJim and you have said regarding the difference in efficiency between battery and air storage as well as real world data on lead acid battery cost and durability.

JRP3 wrote:Let's look at the link you provided:
The OneCAT will be a five-seater with a glass fibre body, weighing just 350kg and could cost just over £2,500.
Note, "could cost".
A 350 kg car is a golf cart. Here's an equivalent "EV" for $4000.00, leaving you $1000.00 for extra batteries:
Cart

So... You're contending that a golf cart able to seat two or three w/o any protection from the elements, or aircon, or the ability to use liquid fuel to travel any farther than however far/fast it'll go w/ it's battery pack is equivalent to the proposed OneCAT? M'kay... :roll:
For long journeys the compressed air driving the pistons can be boosted by a fuel burner which heats the air so it expands and increases the pressure on the pistons. The burner will use all kinds of liquid fuel.

The designers say on long journeys the car will do the equivalent of 120mpg. In town, running on air, it will be cheaper than that.

JRP3 wrote:No, why don't you show me an actual air car with actual data that is for sale at an actual price? You keep asking for proof yet provide none for the air car.
I have already provided proof that even with grossly inflated electricity costs, and the poor efficiency of compressed air as a storage medium, an air car is still cheaper to operate than a BEV because batteries are very expensive per mile. Over the last page or so you have been contending that, contrary to the manufacturer's claims, an air car will cost significantly more than a BEV version due to component costs... So, I'm asking you to provide proof of these statements.
JRP3 wrote:Those tanks probably cost more than a set of batteries, maybe more than 2 sets.

JRP3 wrote:additional EV components are purchased at retail in small quantities. So for the sake of argument increase the cost of the glider and decrease the costs of all EV parts through direct volume purchasing and it balances out.
Here's an example of markup. At work we get our batteries from a distributer, they get the battery from the manufacturer. We sell a battery for $75.00, we paid $40.00, the distributer probably paid $20.00. A mass manufacturer of EV's could bypass the middlemen and really cut costs on all components.


My bad about the Aveo, since you stated retail initially I though you were talking about that. In any event, GM does not build it, and a 08 model certainly doesn't retail for $10k, more like a bit over $12k.
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Re: Why is the Air Car not a viable replacement for fossil f

Unread postby JRP3 » Wed 13 Feb 2008, 19:45:42

yesplease wrote:
JRP3 wrote:
yesplease wrote:I've shown that w/o a substantial drop in battery costs, or increase in electricity prices, there's no way an EV will be cheaper to power per mile than a compressed air vehicle.
No you have not. You have speculated based on what MDI has claimed, not any real world aircar data since there is none.
I have not speculated on what MDI has claimed, I have speculated on what WisJim and you have said regarding the difference in efficiency between battery and air storage as well as real world data on lead acid battery cost and durability.
No because you are including the cost of battery replacement but have no actual data on what the air car and it's carbon fiber tanks will really cost. If you can buy a BEV and a replacement battery pack for less than the aircar, for the same range and performance, then the BEV is cheaper. Again, this is only for the Air car running on air, not the air car running on some other fuel.

So... You're contending that a golf cart able to seat two or three w/o any protection from the elements, or aircon, or the ability to use liquid fuel to travel any farther than however far/fast it'll go w/ it's battery pack is equivalent to the proposed OneCAT? M'kay... :roll:
Don't care about the ability to use other fuels, just the air aspect. Hell stick a portable generator on the golf cart and you can use liquid fuel as well. Meaningless. The golf cart has a roof to protect from rain and open sides so you don't need A/C. :D


My bad about the Aveo, since you stated retail initially I though you were talking about that. In any event, GM does not build it, and a 08 model certainly doesn't retail for $10k, more like a bit over $12k.

Wrong again:
Base Invoice Price: $9,672 - $11,359 *
Base List Price: $10,235 - $12,020 *
http://www.drivenow.com/cars/Summary.asp?model=5211
Now let's build that same vehicle in India with no crash testing, airbags, ABS, etc. and what do you think it will cost? Not to mention that GM can still make money on the Aveo after paying someone else to build it for them!
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Re: Why is the Air Car not a viable replacement for fossil f

Unread postby yesplease » Wed 13 Feb 2008, 20:01:30

JRP3 wrote:
yesplease wrote:
JRP3 wrote:
yesplease wrote:I've shown that w/o a substantial drop in battery costs, or increase in electricity prices, there's no way an EV will be cheaper to power per mile than a compressed air vehicle.
No you have not. You have speculated based on what MDI has claimed, not any real world aircar data since there is none.
I have not speculated on what MDI has claimed, I have speculated on what WisJim and you have said regarding the difference in efficiency between battery and air storage as well as real world data on lead acid battery cost and durability.
No because you are including the cost of battery replacement but have no actual data on what the air car and it's carbon fiber tanks will really cost.
No what? If you have information about how the air car and carbon fiber tanks cost will wipe out the fact that a BEV will cost twice as much as a compressed air car to run per mile, bring it to the table.
JRP3 wrote:If you can buy a BEV and a replacement battery pack for less than the aircar, for the same range and performance, then the BEV is cheaper. Again, this is only for the Air car running on air, not the air car running on some other fuel.
If I can... Where can I buy a new BEV and replacement battery pack for less than what MDI is stating will be the cost of the air car?
JRP3 wrote:
yesplease wrote:So... You're contending that a golf cart able to seat two or three w/o any protection from the elements, or aircon, or the ability to use liquid fuel to travel any farther than however far/fast it'll go w/ it's battery pack is equivalent to the proposed OneCAT? M'kay... :roll:
Don't care about the ability to use other fuels, just the air aspect. Hell stick a portable generator on the golf cart and you can use liquid fuel as well. Meaningless. The golf cart has a roof to protect from rain and open sides so you don't need A/C. :D
You may not care about it, but if you consider that golf cart to be equivalent, as you have stated, to MDI's proposed OneCAT, have got a bridge for you buddy! :lol:
JRP3 wrote:Let's look at the link you provided:
The OneCAT will be a five-seater with a glass fibre body, weighing just 350kg and could cost just over £2,500.
Note, "could cost".
A 350 kg car is a golf cart. Here's an equivalent "EV" for $4000.00, leaving you $1000.00 for extra batteries:
Cart

JRP3 wrote:
yesplease wrote:My bad about the Aveo, since you stated retail initially I though you were talking about that. In any event, GM does not build it, and a 08 model certainly doesn't retail for $10k, more like a bit over $12k.

Wrong again:
Base Invoice Price: $9,672 - $11,359 *
Base List Price: $10,235 - $12,020 *
http://www.drivenow.com/cars/Summary.asp?model=5211!
Wrong again. The Aveo5 and the Aveo are different vehicles. :roll:
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Re: Why is the Air Car not a viable replacement for fossil f

Unread postby Frank » Wed 13 Feb 2008, 20:23:33

Thanks for the links to Youtube; they didn't change my mind but it was interesting.

I don't understand your cost analysis. If a 6-volt golf cart battery (Trojan T-125) is used with your assumptions I calculate battery costs of $.025/mile. With electricity at $.20/kwh and 100 whr/mile that's $.02/mile electricity cost or $.045/mile total.

If an air car is five times less efficient wouldn't it use $.10/mile electricity which is twice as expensive as the BEV in this example?

- One battery = 240 AH * 6 volts = 1440 watt-hr (nominal)

- 80% DOD gives ~1100 watt-hr available, call it good for 10 miles range at 100 wh/mi

- 800 cycles would therefore provide 8000 miles range

- 7 wh/$ works out to ~$200/battery

- battery cost = $200/8000 miles = $.025/mile

BTW, I purchased twenty T-125's 5 months ago for ~$130 each and our electricity cost is $.19/kwh here in Maine so this analysis is very a-propos for me. (In fact I did it before I built my own conversion vehicle.) Good AGM's would easily cost that though. Most vehicles would use 2-3 times the energy but the 100 whr/mi is probably a good assumption for the smaller prototypes.

I think the most interesting thing that may develop from this is the so-called hybrid version.
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Re: Why is the Air Car not a viable replacement for fossil f

Unread postby JRP3 » Wed 13 Feb 2008, 21:02:16

If I can... Where can I buy a new BEV and replacement battery pack for less than what MDI is stating will be the cost of the air car?

Where can I buy an Air car at any price?
Wrong again. The Aveo5 and the Aveo are different vehicles.

Obviously the Aveo I was referring to the whole time was the Aveo5, and the omission of the "5" does nothing to change my numbers. Nice attempt at deflecting from the real issue, which is, to be clear, that a small glider can be built quite cheaply.
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Re: Why is the Air Car not a viable replacement for fossil f

Unread postby yesplease » Wed 13 Feb 2008, 23:30:24

Frank wrote:I don't understand your cost analysis. If a 6-volt golf cart battery (Trojan T-125) is used with your assumptions I calculate battery costs of $.025/mile. With electricity at $.20/kwh and 100 whr/mile that's $.02/mile electricity cost or $.045/mile total.

If an air car is five times less efficient wouldn't it use $.10/mile electricity which is twice as expensive as the BEV in this example?
Shh..... :shock: ;)
Mah bad! :oops:
Frank wrote:- 80% DOD gives ~1100 watt-hr available, call it good for 10 miles range at 100 wh/mi

- 800 cycles would therefore provide 8000 miles range
T-125s peak in terms of capacity at 775 cycles@60% DOD according to this. Any more or less and you get less out of the battery. In that respect my estimate was about 30-40% above. They also won't given the 20hr rate unless you actually plan to draw them down over the course of 20 hours. I think 175ah over an hour or two is reasonable. There are plenty of calculators for Peukert's if you wanna figure out the exact figure over whatever your route is.
Frank wrote:Most vehicles would use 2-3 times the energy but the 100 whr/mi is probably a good assumption for the smaller prototypes.
It's actually a horrible assumption for a city car IMO. One of these, either an EV or CA (compressed air) version would only weigh around 5000N with a driver and average about 20mph. With LRR tires (Crr=.007) it would only use around 20Wh/mile at a steady cruise, or assuming the energy requirements double because of stop and go driving, only about 40Wh/mile.
Frank wrote:I think the most interesting thing that may develop from this is the so-called hybrid version.
I'd say it's a necessity. It'll have a higher operating cost per mile if charged at home at ~$.06/mile. The only way for it to drop below would be to cut electricity costs in half, which seems reasonable since MDI proposes CA filling stations, which as business', have access to TOD metering for their filling equipment, and compressing air in large volumes is cheap in terms of energy storage compared to doing the same for electricity. So... It's major advantages must come from being able to use many different kinds of fuel efficiently and having cheap off-peak energy storage.
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Re: Why is the Air Car not a viable replacement for fossil f

Unread postby yesplease » Wed 13 Feb 2008, 23:30:47

JRP3 wrote:Where can I buy an Air car at any price?
The same place you can buy an EV version of that platform. ;)
JRP3 wrote:
yesplease wrote:Wrong again. The Aveo5 and the Aveo are different vehicles.
Obviously the Aveo I was referring to the whole time was the Aveo5, and the omission of the "5" does nothing to change my numbers.
It does if you expect your statements to be interpreted correctly. :P
JRP3 wrote:Nice attempt at deflecting from the real issue, which is, to be clear, that a small glider can be built quite cheaply.
What attempt at deflection? I'm just responding to your posts in the same way you've been responding to my posts. If you want to show a small glider can be built quite cheaply then link to the pertinent figures/material that shows this, and, hopefully, use the right terms/names. :-D
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Could this make enough of a difference ?

Unread postby loveandrage » Sun 06 Jul 2008, 14:28:09

Most techno fantasies won't save us because they are all consumers of energy not replacements of energy or use alternative power sources. But could compressed air reduce consumption enough to make a difference?

1 video, 2 solutions. 1 compressed air car, the other a redesigned engine.

http://www.youtube.com/watch?v=QmqpGZv0YT4

It has me second guessing my fears of the future ....

I believe they call that hope, but is it unfounded?

:-D
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Re: Could this make enough of a difference ?

Unread postby TreeFarmer » Sun 06 Jul 2008, 15:33:15

A car like that would be fine for commuting. You have to remember though that it takes energy to compress the air, in this case electrical energy.

We use a tremendous number of BTU's of oil everyday for commuting. If you want to replace gasoline/diesel with compressed air you will need that many BTU's of electricity from somewhere. This will mean coal, nuclear, wind, solar in enough volume to replace the oil you are not using.

I think the bottom line on this technology is that it can (apparently) replace a significant amount of oil consumption but, you have to have the electrical infrastructure in place to replace it. I am doubtful that the current electrical grid can handle it.

TF
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Re: Could this make enough of a difference ?

Unread postby jlw61 » Sun 06 Jul 2008, 15:49:35

I was under the impression that the electrical grid at night is not as heavily used as the day time. Something like an air compressor could easily be set to run automatically at night.
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Re: Could this make enough of a difference ?

Unread postby WisJim » Sun 06 Jul 2008, 16:32:31

Compressing air takes a LOT of energy. It is not a very efficient process even at the industrial level, and for personal transportation, electrical storage in available batteries is at least as efficient, and readily available for use.
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Re: Could this make enough of a difference ?

Unread postby chakra » Sun 06 Jul 2008, 17:51:27

I think if first world nations were stirred enough, and a huge focus was placed on quickly replacing the fleet with these motors, it could happen.

Placing huge tariffs on gas engines while giving huge tax rebates on these would be a good step. If it cost 15,000 to buy one of these cars but there was 10,000 dollar rebates on them, just watch how many people would demand them. Every car company in the world couldn't build them fast enough.

It would take massive intervention to get the patents to all car manufacturers and drive in the necessity to start building these almost exclusively as fast as humanly possible.

IF, and that's a big if, that did happen we'd probably do alright. We'd probably float along nicely for decades.

Too bad it probably won't happen but it's nice to know that there are options if there was enough fire under our feet and people did the right things very soon.
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Re: Could this make enough of a difference ?

Unread postby mos6507 » Mon 07 Jul 2008, 04:01:43

I've heard the air car has a really low range and the performance degrades quickly. Really, compressed air is basically the equivalent of a wind up toy. It's not the best way to move a car.
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Re: compressed air car

Unread postby loveandrage » Tue 08 Jul 2008, 07:55:05

big tex,

can you sight your source instead of "i heard ..." ?

and as far as to the poster that says it takes a lot to compress air, the video sighted an extremely cheaper price than gasoline and farther range. Yes it takes electricity to compress, no it's not free, but a vast improvement.

i had a friend take some time reviewing and responding by email which i'd like to post his thoughtful comments here ....

--------------------------------------------------------------------------------

Probably the most dramatic point of the YouTude video was when the second inventor held up his air engine which can power a car but is only about the size of a shoe box! Per Wikipedia, the advantages seem to *far* outway the disadvantages... Mike

Advantages
The principal advantages of an air powered vehicle are:[7]
Much like electrical vehicles, air powered vehicles would ultimately be powered through the electrical grid.
That makes it easier to focus on reducing pollution from one source, as opposed to the millions of vehicles on the road.
Compressed air engine reduces the cost of vehicle production by about 20%, because there is no need to build a cooling system, spark plugs or silencers.
Most compressed air engines do not need a transmission, just a flow control.
Transportation of the fuel would not be required due to drawing power off the electrical grid. This presents significant cost benefits. Pollution created during fuel transportation would be eliminated.
Very low self-discharge rate (most batteries will deplete their charge without external load at a rate determined by the chemistry, design, and size, while compressed gas storage will have an extremely low leakage rate)
Long storage lifetime device (electric vehicle batteries have a limited useful number of cycles, and sometimes a limited calendar lifetime, irrespective of use). This means that batteries in operation are much more expensive than compressed air storage, and are more polluting because a lot more pollutant material needs to be used (typical car batteries are made from sulfuric acids and lead).
Lower initial cost than battery electric vehicles when mass produced. One estimate is €3,000 less.
Compressed air not subject to fuel tax at present (one taxing method would apply also to electric cars by taxing the electricity used for compression or charging).
Expansion of the compressed air reduces its temperature and heat from the passenger compartment may be cooled using a heat exchanger, providing both relief from hot weather by air conditioning and increased efficiency.
Zero pollutant emissions from the vehicle itself.
Compressed air is not a fire hazard, only a rapid depressurization hazard (this can be mitigated by using carbon fiber tanks).
Air turbine technology, closely related to steam turbine technology, is a practice over 50 years old. It is simple to achieve with low tech materials. This would mean that developing countries, and rapidly growing countries like China and India, could easily implement a less polluting means of personal transportation than an internal combustion engine automobile.
Possibility to refill air tank at home (using domestic power socket).[8]
Lighter vehicles would mean less abuse on roads. Resulting in longer lasting roads.
The price of fueling air powered vehicles will be significantly cheaper than current fuels.
Disadvantages
The principle disadvantage is that of indirect energy use. Energy is used to charge the high pressure tank, which tank - in turn - energizes the propulsion. Any indirect step in energy usage results in loss. In the case of a compressed air car: (1) energy loss when fossil fuel energy is converted to electric energy; (2) energy loss when electric energy is converted to compressed air energy.

Further disadvantages:

When the air is expanded in the engine, it will cool down via adiabatic cooling and lose pressure thus its ability to do work at colder temperatures. It is difficult to maintain or restore the air temperature by simply using a heat exchanger with ambient heat at the high flow rates used in a vehicle, thus the ideal isothermic energy capacity of the tank will not be realised. Cold temperatures will also encourage the engine to ice up. thermodynamics.[9]
The major problem of all compressed air or liquified air cars is the lack of torque provided by the compressed gas and the high cost to compress the gas. This was shown to be the case starting in 1903 with the Liquified Air Company car of London England [10]
Long refill time when refilled using a home or low-end system (circa 4 hours). However, at a commercial station refilling would take only 3 minutes.[11] But for that, fueling stations would have to invest in new low-cost dispensers.
Governments would either lose tax income or have to adapt their taxation strategies.

http://en.wikipedia.org/wiki/Air_vehicle

Mike in south Austin
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Re: compressed air car

Unread postby JRP3 » Tue 08 Jul 2008, 08:06:53

Compressed air is an inefficient use of electricity. Most of the "positive" arguments presented are even more positive for BEV's. The self discharge "issue" for batteries is a non issue. How many vehicles sit unused for months at a time? Discharge rates for batteries are extremely low anyway.
No matter how simple an air motor is an electric motor is even more simple, with one moving part, and will last longer. Remember with your air car you have 2 motors to maintain, the compressor and the air motor.
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Re: compressed air car

Unread postby lper100km » Tue 08 Jul 2008, 12:21:09

My recollection of air compressors is that they are used industrially only where absolutely necessary. They power tools in hazardous environments and provide high pressure air for industrial processes. Wherever else, electrical power has been shown to be more effective and certainly more efficient as a driver for localized, portable tools. Air compression is highly inefficient. Most of the energy of compression is ‘wasted’ as heat – in fact up to 80% . Leakages can add another 30% loss to the stored compressed air. Then, the energy represented by the compressed gas has to be converted to mechanical motion via motor, which again is an efficiency nightmare. Plus the noise, though this can be assuaged at the cost of more efficiency loss. I think that maybe, some 10% or less of the energy input – the electrical outlet – is actually delivered to the road wheels. ie 10 US galls of gasoline equivalent are required to get 1 US gall gasoline equivalent to the road wheels. That’s being generous.

I am somewhat rusty on this, but storing the energy equivalent of one US gall of gasoline in a compressed air tank would require a 2,750 l capacity tank (725 US gall) at 70 bar (1,000psi). This is five to ten times the size of an SUV gasoline tank. Let’s say that the efficiency from the tank to the road is approx the same for a gasoline and an air motor, then the effective range is roughly the same, dependent upon the size and load, but around 25miles plus/minus. To be sure, the pressures and tank sizes can be played around with, but that’s a mere detail. It’s the uselessness of the concept that I am addressing.

If someone sees an error in the numbers please comment. Otherwise, I have to conclude that this is among the worst of ideas ever brought forward.
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