High pressure tanks for air cars
 

I'm opening this thread because I want to find your opinion about my patent pending solution for high pressure tanks.
The patented model covers tanks made from layered cells
I'm offering free information on my website ( jopatent) about the posibility of using this model for a new kind of battery, the thermodynamic batery, high pressure tanks (1000 bars and above) for stationary and mobile aplications.
At this moment an air car has compressed air at 300 bars and can travel 200 km. If the same quantity of air is at 1000 bars the distance covered could be two or three times higher.
So what do you think?
I can't put a link to my website so you have to dig a little.

The air tanks could be made to form the cars frame and front & rear bumper areas so as to provide some crash resistance, space savings and weight distribution.

Yes, any form can be designed in every place available in the car structure.
More the compressed air can be obtained at home from renewable energies and transferred when necessary from a stationary tank.

How efficiently can you compress air? 10% 20%?

At "low" pressure, 100 PSI or so, it takes about 4 hp of air compressor to run a 1 hp air motor. The efficiency is worse at high pressure.

To JRMichler
 

Yes low efficiency looks like a problem, but if you'll find my patent online you'll see that you can take from 0 to 100psi and in another cell from 100 to 200 and so on. More check the thermodynamic that occurs in the cellular tank and you'll find interesting things. I can't give you the link to my site where I explain some of the high efficiency thermodynamics that results, because the rules of this site do not allow.

Q&A received until now on other forums.

Q:
1. Does the increased pressure in the inner cells really make up for the increased size and weight of the overall structure associated with the outer cell layers?
2. Do you see the greater safety as resulting from the lower level of energy released if one cell fails compared to a single monolithic tank? If so, what happens if the failure of one cell results in over stressing adjacent cells?
3. I am not at all comfortable with a system whose safety depends on that large an array of individual valves and a control system which coordinates them. What sort of fail-safes in your design address these concerns? If one or more cells in a middle layer fail to pressurize properly, what is the effect on the inner layer cells associated with them?
4. How are the valves and pressure sensors in the inner layers tested and serviced?
A:
1. Increasing pressure = increasing wall thickness for usual tanks. In my patent the same weight is redistributed in inner cell walls, for safety. same weight of the tank but super safety. A bullet will cross the tank and will destroy few cells on his road and the rest of the cells will function with no problem. Inner cells have larger thickness walls.
2. Yes. The walls of the cells are calculated to resist the pressure difference between cell and worst case external pressure. Pcell=F/Scell, smaller S means at the same thickness higher pressure. I have a website explaining this.
3. If a valve or a group of valves fails only the corresponding cell are blocked the rest of the tank will function at a reduced capacity.
4. Big problem yes. For that reason the patent covers blocks of valves. More on jopatent. There are also constructive solutions for tanks made from blocks of cells that can be changed in case of failure.
Q:
Energy conversion efficiency of compressed air would be much less compared to the traditional flooded batteries. This means the size of panel array must be increased to generate the same amount of power drawn from a battery.

Do you have any cost analysis/comparison between a battery system vs compressed air system for residential use? I'm interested to know and I hope I can get rid of costly batteries. Maybe steel reinforced concrete will work as a tank also.
A:
1)Compressing air has usually 15% efficiency. Heat is the difference. Usually the heat generated can be converted back to energy (the Stirling engine 50% efficiency, gas turbines), or can be used for home use (air or water heating) so overall efficiency increases. More the thermodynamics of this tank has special properties allowing (for the moment in theory) thermodynamic systems with more than 65% efficiency.
2) Using conventional batteries means paying more for replacing batteries than for grid electricity (Pb batteries should be replaced after 500 cycles, lithium after 2000-3000) How much do you pay for gasoline on 100 miles. An air car needs 3$ compressed air. No pollution, it cleans the air (dust from air condenses in the tank and can be eliminated locally) and other advantages can be obtained. I'm writing an e-book on the subject (hope to have time to explain all the thinks I've found).

Now this I would like to see.

I always assumed (as have others) the only way to overcome the inefficiency within a compressed air system was scale.

For example, if one were to develop a large scale system in an ocean body of sufficient depth the act of compressing air using the depth of the ocean could potentially go above 80% eff because of the temperature difference going from the top of the water to the depth needed.

If one had a market near an ocean that required massive amounts of compressed air it could work but then the inefficiency of the motor side of things comes into play as well.

A model image might be a bit of a discussion piece.

Cheers
Ryan

I'm having problems with the math ...
 

Please correct this where I have it wrong:
- 15% efficiency from compressing air (waste heat used for other things, but not for compressing air)
- 3$ of compressed air will get an air car 100 miles. Where I live, 3$ is about 30 kw-h. At 15% efficiency, that's 4.5 kw-h of energy put into the air tank, which would be too little to move an air car for 100 miles.
- that does not take into account the efficiency of the air motor, the drive train, etc and measure power delivered to the road. I guess we can ignore that part for now.

You mention that an electric car has more cost for replacing the batteries than for the electricity purchased from the grid. I don't have experience with that (I'm sadly not driving electric as yet), but that sounds reasonable to me.

Here are the numbers that I'm using. The pack I've sized (from web site information) for my project is around $10,000 for a 15 kw-h pack that should give my converted 5000lb Chevy S10 a range of about 30 miles of highway travel. If the battery pack lasts 5000 cycles or something like 8 years (charging twice a day, once at work and once at home), it will have been charged with 5000 * 15 kw-h (worst case) * 0.10/kw-h (present price in my area) and that would cost $7500. If it only lasts for 2000 or 3000 cycles, the batteries would cost double what the electricity cost (my apologies for assuming constant costs on the electricity). I've left out the efficiencies of the charger, the batteries, the drive train - these are all percentage losses that add up ... but the discussion so far is not at that level of detail.

By way of comparison, how much does your proposed tank system cost (up-front capital cost - I am assuming that you have a prototype), to compare to the $10,000 in my example above? Please include the compressor as well, with the water knockout filters, air drying equipment, etc. I know nitrogen is liquid at 1000 bar, not sure about air.

What does it cost to certify your proposed tank (the regulators can take a long time to decide - again, I assume that you have this taken care of), to compare to no cost listed above as I am not aware of a certification required on batteries in mobile use. And how often would the tank need to be tested? (I would assume 5 years without further research or evidence) My propane tank is regulated as portable equipment and costs me $25 every 5 years to trade it in - I could pay them to certify the same tank, but that would be more. The SCOTT airpack that I use as a volunteer firefighter costs something to certify ... not sure how much since I don't pay for it ... and I think the test that it is sent away for is called a hydro-test, it's done every 5 years. The Scott Airpack is only rated at 100 bar. A 1000 bar certification for mobile use - I would expect to cost more.

And what would it cost to drive - 30 miles in my example above, but I'll take costs for 100 miles or any other data you may have and scale it to make the comparison work. $3 of electricity does not appear to work out to 100 miles as listed above.

If we're to compare costs, in my opinion, all of the costs should be identified and quantified. My example above comes in at about $4 per day for the battery pack ($10,000 / 2500 days) and $3 for the electricity (1.50 per charge, 2 charges per day) for a total of $7. This compares well to the 7.5 liters of gas I use to drive to work and back each day, at 1.25 per liter. And that ignores the advantages of no oil changes, filter changes, other reduced maintenance, and spending less time at a gas station (which I currently list as priceless)

If I use your numbers, worst case, of 2000 cycles. $10,000 / 1000 days is $10 per day. Still $3 for the electricity * 1000 days = $3000. $13 per day - how does that compare to your air tank solution. Does it take less than $3 of electricity for your air tank solution?

If you've filed for patents then you have put a lot of time and effort into the analysis, the documentation process, and the red tape that is involved ... likely lawyers as well ... so you must have some 'example numbers' that you are planning to show investors, venture capital people, etc. Please post them for us to critique.

I'm trying to evaluate your claims as posted. If your system is $3 per day compared with $7 for my proposed system - I will gladly switch technologies. But I'm having problems with the math.

By the way, even as a newbie, you can post a link like this:
www dot my-patent-is-here dot com

We can't click on it directly, but it has worked for others in the past.

I look forward to further information.

Most people do not know that a patent means only that nobody else did it first. A patent does not mean that the idea works, only that it is new.

I should know. One of my patents is for something that does not work. But the patent is still valid.