# Question about supplemental power generation



## Ziggythewiz (May 16, 2010)

Go compare the cost/kwh of those tanks to batteries and you'll have your answer.


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## veoeluz (Apr 20, 2012)

Ziggythewiz said:


> Go compare the cost/kwh of those tanks to batteries and you'll have your answer.


But wouldn't the tanks be much lighter than just running extra batteries? I know the question still lies in how much potential you can stuff into those tanks, but I figured that half the benefit would be quick and convenient fillups on the road of a renewable source of energy.


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## TigerNut (Dec 18, 2009)

veoeluz said:


> I was just thinking about different ways you could utilize an outside (or rather, inside) power source to generate energy as you go. This is not a free energy post.
> 
> I saw a concept car they were making in Thailand that was basically a pneumatic car. The point here is that they were using two rather large (as a percentage of the car's volume) carbon fiber air tanks. What if you rigged up some sort of pneumatic electric generator that you flip on to use when/as you need it as a sort of backup. Not only could you potentially raise the range, but you could also refill those tanks at any gas station (as long as they have an air pump.)
> 
> What do you guys think? Too much extra weight? I was thinking a small light truck with the extra bed space for larger tanks. I know carbon fiber tanks are expensive, but I was just looking at it from a practicality standpoint.


I don't have the formulas for energy stored in a compressed gas handy, but think of it this way, just to get a rough estimate of the volume required: If you have a 2 HP compressor with a 20 gallon tank, it will take it about 10 minutes of continuous running to get that tank to the cutoff pressure - usually about 120 PSI. If you had perfect energy recovery (and for compressed-gas motors that is distinctly not true, due to adiabatic effects), your 20 gallon tank would give you a maximum of 2 HP advantage for at most 10 minutes, and then it's toast. A larger tank or higher pressure will give you proportionally more energy storage, but will require a proportionally longer time to refill as well - even commercial tire shops don't usually use more than about a 5 to 10HP compressor, and most gas stations have nothing like that. If you can't get high pressure from the gas station, then you get no significant energy storage.

Seriously high pressures (such as for scuba tanks) require multistage compressors with intercooling and moisture scavenging, and I'd be really scared of a large tank at high pressure. Filling would not be quick or convenient at least partially due to safety concerns.


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## Ziggythewiz (May 16, 2010)

If the compressor is running at 2 HP, you're likely to get ~1/2 a HP of stored air, and after converting that to electric you'd be lucky to get half of that. The air starts out light, but it can get heavy depending on the compression, plus you have the added weight of he tank and the generator.

You're probably better off with supercapacitors or flying geese or something.

An air powered car can work great, but trying to add that to electric doesn't make much sense.


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## veoeluz (Apr 20, 2012)

TigerNut said:


> I don't have the formulas for energy stored in a compressed gas handy, but think of it this way, just to get a rough estimate of the volume required: If you have a 2 HP compressor with a 20 gallon tank, it will take it about 10 minutes of continuous running to get that tank to the cutoff pressure - usually about 120 PSI. If you had perfect energy recovery (and for compressed-gas motors that is distinctly not true, due to adiabatic effects), your 20 gallon tank would give you a maximum of 2 HP advantage for at most 10 minutes, and then it's toast. A larger tank or higher pressure will give you proportionally more energy storage, but will require a proportionally longer time to refill as well - even commercial tire shops don't usually use more than about a 5 to 10HP compressor, and most gas stations have nothing like that. If you can't get high pressure from the gas station, then you get no significant energy storage.
> 
> Seriously high pressures (such as for scuba tanks) require multistage compressors with intercooling and moisture scavenging, and I'd be really scared of a large tank at high pressure. Filling would not be quick or convenient at least partially due to safety concerns.


Well, the tanks that were used on those pneumatic cars each (there were two per vehicle) were around 25 gallons and were filled to around 250psi. 

To clarify, I wasn't proposing you use the air to propel the car or anything, but to generate electricity through some sort of method.

So with 50 gallons at 250psi, I was just thinking this energy could be used to generate electricity in a similar fashion that I've seen people use gasoline hybrids to generate electricity. 

With respect to the safety of the tank - that's why they used carbon fiber. It's stong, but won't cause an "explosion" if ruptured. Though I'm sure it'd still be a sight to see.


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## TEV (Nov 25, 2011)

Hi, 
Filling those air tanks require a special compressor, so you wouldn't be able to use the compressor from the gas station.


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## veoeluz (Apr 20, 2012)

TEV said:


> Hi,
> Filling those air tanks require a special compressor, so you wouldn't be able to use the compressor from the gas station.


I can see where that _would_ be a problem. But if it's just used to extend your daily commute range? I guess it just kinda depends on what you have to work with.. How much the pneumatic generator would put out and how much room you'd have for tanks. 

Anywho.. it was just a thought I had. I've not even been able to find a place that makes large capacity carbon fiber tanks. They might've been custom made for that company that made those pneumatic cars..


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## Ziggythewiz (May 16, 2010)

Once again, there's no point in speculating much without numbers. Look em up, run the numbers and see what the result is. If compressed air is somehow far cheaper/lighter than LiFePo4 then it's a great idea that we'll all want to incorporate.

When it comes to physics, most issues are just a couple simple math problems.


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## Duncan (Dec 8, 2008)

Ok lets look at the numbers

Assume perfect compression/expansion
1m3 (1000litres) air tank
Energy to get to 10Bar (150psi) 
Take 10m3 and squeeze it into 1m3
Piston (area 1m2) moves 9 meters with a force between zero and 10Bar x 1m2
10 Bar = 10 x 10-power5 N/m2 = 1 Million N - average load = 500KN

500KN x 9 meters = 4.5 MJoules = 1250 Watt hours 1.25Kwhrs

Considering you would only get ~ half of that back - not worth messing with


Lets get up to SCUBA pressures - 200Bar
1m3 (1000litres) air tank
Energy to get to 200Bar (3,000psi) 
Take 200m3 and squeeze it into 1m3
Piston (area 1m2) moves 199 meters with a force between zero and 200Bar x 1m2
200 Bar = 200 x 10-power5 N/m2 = 20 Million N - average load = 10 Million N

10MN x 199 meters = 1990 MJoules = 552 Kwhrs (about half "available")

So a 25Kwhrs "pack" - would be a tenth of that - 100 litres of Scuba cylinders - steel or aluminium would be 100Kg+

Carbon fiber tanks would be a lot lighter ~ 10 off 2 Kg tanks

Compared to batteries
Need very high pressures to be comparable
Three stage air compressor much much more expensive than battery chargers
Need carbon fiber tanks - Steel Scuba tanks are ~ $400 for a 10 liter tank? - 10 tanks - $4,000

Not as bad as I thought


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## ga2500ev (Apr 20, 2008)

veoeluz said:


> I was just thinking about different ways you could utilize an outside (or rather, inside) power source to generate energy as you go. This is not a free energy post.


Smart of you to point that out.



> I saw a concept car they were making in Thailand that was basically a pneumatic car. The point here is that they were using two rather large (as a percentage of the car's volume) carbon fiber air tanks. What if you rigged up some sort of pneumatic electric generator that you flip on to use when/as you need it as a sort of backup. Not only could you potentially raise the range, but you could also refill those tanks at any gas station (as long as they have an air pump.)


I've spent quite a bit of time looking at alternatives to petrochecmicals as a hybrid substitute. Something that is quickly refillable and does not require massive infrastructure to pull off. Compressed air was one of my first tacks. It doesn't work. The power density is way too low to be of any usefulness.

Better would be liquid nitrogen. Fundamentally the same concept except that liquid has a much better energy density than air due to the energy of the phase change. LN2 expands to 700 times its volume when changed to air, and the LN2 can be kept at near atmospheric pressure, not at 6000 PSI like compressed air. The source material is everywhere, pretty much anyone can make it. Since it's liquid it can be transferred between containers quickly. The University of Washington and the University of North Texas did some experements in LN2 vehicles about 10 years ago. Look up "Cool Car".



> What do you guys think? Too much extra weight? I was thinking a small light truck with the extra bed space for larger tanks. I know carbon fiber tanks are expensive, but I was just looking at it from a practicality standpoint.


It simply won't get you far. Put it this way, it won't get you any farther than if you simply had put in that weight in batteries.

You're on the right track. I just think that compressed air is the wrong tool to get you there.

ga2500ev


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## mizlplix (May 1, 2011)

Ditto.

Miz


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## ga2500ev (Apr 20, 2008)

gottdi said:


> Buy some extra batteries and just fill those for your extra distance. Cheaper, lighter, and you go sooooo much further. Just think of all the electricity wasted to fill those tanks only to make a tiny bit more by running a generator with the compressed air to recharge the batteries. Makes ZERO sense. Just use the electricity and don't bother with conversions.
> 
> Be sure you use lithium batteries and not lead acid for all your batteries.


There is a single failure mode that drives all of these discussions Pete: what do you do when you run out of energy? There's nothing about "Buy some extra batteries." that solves that issue because no matter how many cells you have in your pack, when they are empty, you are stuck.

That is the sole reason there are so many discussions on compressed air, liquid nitrogen, diesel/gas generators, solar, hydrogen, methanol, and the like. Because like it or not, with a gas car, when the tank is on E, it's easy to refill and get going again. With an electric vehicle, when the battery is on E, precious few options with a short refill timeframe exists.

In short, I can hop in my truck right this minute and drive the 2100+ miles from Atlanta to the Pacific Ocean without stopping for more than 15 minutes at a time. Even with an unlimited supply of cells, which I cannot afford anyway, there is no way to do this with a pure EV like the Leaf (at least that I know of).

Then there is the issue of amortized cost. With a gas car, even if the 10 gallon tank is situated for 300 mile range, and the common usage of the car is within that range, there's no issue if an emergency trip doubles or triples that range. Just buy an extra tank of gas.

Batteries are the proverbial "gas tank". So buying extra has a large cost associated with it, where it's not clear that the return on it is valid. Doubling the range of an EV with lithium can cost thousands of dollars. Where is the ROI if the doubling of the battery size only gets used in 1 out of 100 trips?

All of this is to say that hybrids are going to need to be a vital phase of the transistion from gas only vehicles. The problem with current hybrids is that they are E-assist vehicles, not E-vehicles. All except for the Leaf, the Volt (costs way too much), and custom/DIY setups gas is the primary motivator of the vehicle. So it isn't much progress.

LN2 isn't perfect by any stretch. It's inefficient. It adds weight to the system. There are dangers with carrying around supercooled liquids. But it can be made with electricity, and the source is plentiful: just pull it out of the air. Finally it can be refueled quickly, which is the marked disadvantage of batteries, even with fast charging.

ga2500ev


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## mizlplix (May 1, 2011)

{From an owner of 3 EV's (plug in's, not those hybrids everyone sez r electric}

"When your gasoline/diesel tank is empty, it is empty too...."

If you are an idiot, and can not plan ahead, no matter what you drive, you are going to run out..PERIOD.

Take command of your life. You ran your car out- not the battery.

(Flame away-I have thick skin)

Miz


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## ga2500ev (Apr 20, 2008)

mizlplix said:


> {From an owner of 3 EV's (plug in's, not those hybrids everyone sez r electric}
> 
> "When your gasoline/diesel tank is empty, it is empty too...."


You missed the point. It's not the fact that the gas tank is empty. It's the fact that it will take a minimal amount of time to refill, with over 100,000 stations in the US to do so. In fact, gas tanks do not typically go empty precisely because the infrastructure is in place. Gas has already set an expectation of 5-10 minutes tops to refuel. Anything outside of that window is a non starter for most drivers. Current EVs simply do not have that infrastructure in place.



> If you are an idiot, and can not plan ahead, no matter what you drive, you are going to run out..PERIOD.
> 
> Take command of your life. You ran your car out- not the battery.
> 
> ...


No need to flame. It's an infrastructure issue, not a planning issue. We need discussions like these because we need the ability to transition from where we are now to something electric based.

From an infrastructure standpoint, driving an EV is analogous to having a 3 gallon gas tank and no gas stations except for at home. You can plan until the cows come home. But the first time you have to take an emergency side trip that's outside of your range, you are stuck. The solution isn't to call for a 4 gallon tank. The solution is to figure out how to put up stations that you can refuel in short order, so that even if you have a 3-4 gallon tank, you can drive 100 miles, stop in and refuel in 5-10 minutes, and be on your way.

It would also be extremely helpful if that fuel was some form of electricity, instead of reverting back to gas, which defeats the purpose.

No matter how hard you try, there is no way to explain away the deficiency this situation creates for pure plug-in EVs to the general populace. Be it flow batteries, compressed air, LN2, electrified roads, or even battery swapping, there has to be some fast fuel electric based infrastructure in place in order for EVs to make it in to the mainstream. The only mainstream hybrids right now are all gas based. They are the only commercial EV type vehicles (with the exception of the Leaf, which of course is range limited) that the vast majority of drivers will consider. There needs to be a discussion about alternatives to range limited pure EVs and gas based hybrids. Note that all of these should be hybrid technologies coupled with pure plug in EVs, not a replacement for batteries and plug in charging.

So while no flame is required, let's not kill this thread based on the argument that "If you allow yourself to get out of range, then you must be an idiot."

ga2500ev


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## mizlplix (May 1, 2011)

And you, sir, miss my entire point. 

We on this forum, are visionaries. We look beyond temporary conveniences, inventions and conventions. We advocate the entire replacement of the existing petro fuel society with something cleaner and sustainable. 

I seriously doubt you will make any converts to support the same old party rhetoric. We have heard it all.

So, our system is not perfect. Yours ain't neither....and we are still perfecting ours.

To most of us, a "hybrid" is just another polluter.

Miz


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## ga2500ev (Apr 20, 2008)

mizlplix said:


> And you, sir, miss my entire point.
> 
> We on this forum, are visionaries. We look beyond temporary conveniences, inventions and conventions. We advocate the entire replacement of the existing petro fuel society with something cleaner and sustainable.


I most certainly did not miss your point. If I did, I would have been calling for what already exists: a gas ICE hybrid.

Unfortunately, you cannot replace an existing infrastructure without addressing the conventions of the existing one. No matter how much cleaner or sustainable the goal that you envision, if it isn't perceived as better than the current incarnation, it'll never get any traction.

And being able to reliably move an electric vehicle outside of a carefully planned route isn't simply a temporary inconvenience. The ability to fast refuel is a crucial one. I just want to clarify that I do not mean refuel in the petrol only sense. I mean energy replenishment in EV terms. Honestly, if you can give me a 100 mile charge in a 10 minute window, I'll declare victory and keep moving. But I haven't seen it yet.




> I seriously doubt you will make any converts to support the same old party rhetoric. We have heard it all.
> 
> So, our system is not perfect. Yours ain't neither....and we are still perfecting ours.
> 
> ...


OK. Now that you've gotten your rhetoric out, please come back and address the technical issues of my proposal. LN2 only requires electricity and air. It's neutral to the environment. Nitrogen exists all over the planet. The electricity can be generated from sustainable resources such as solar or wind.

Here's an example of using Liquid Air for energy storage.

It's not visionary to try to shut down new ideas. Nor is it visionary to want a sea change without addressing the infrastructure required to pull it off. Note that I didn't just shut down compressed air or extra batteries. I gave reasoned arguments of why they are not sustainable ideas.

All I ask is that you do the same with mine instead of simply dismissing it out of hand.

ga2500ev


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## drgrieve (Apr 14, 2011)

When we are driving 500 kwh packs (2000 miles) and charging at 250 kwh (150 mile per 10 minutes) these sort of discussions become fairly moot. (possibly sooner than you think!)

In the end we'll be back to large SUV's and trading reverse air con for resistive heaters and using DC motors over AC.

As efficiency will be traded for cost and convience.

To reach utopia we just need to stick to the path and have faith.


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## ga2500ev (Apr 20, 2008)

gottdi said:


> It is not perfect or good or practical in ANY stretch.Terrible inefficient and expensive. Quickly refueled? Hardly. Your not going to pull it out of the air in a few minutes.


Station Pete. Stations. Pull up somewhere that already has it available, pour it in the tank, and drive away. The station keeps the high powered compression equipment and has the power to keep their tanks topped off. The EV doesn't need to generate any LN2. Also users can generate and store their own at home and can top off their tanks at home while they are recharging.

The station can even be dual mode, facilitating some direct plug in charging of the batteries at the same time.

The key point is that stations can be erected in short order, and that refillability goes down into the same 5-10 minute range that fueling gas cars now.

I acknowledge that the setup is crappy. But when the alternative is carrying $50K of batteries and hoping that charging stations directly connected to power plants (250 Kw, seriously?) come online without breaking our backs costwise, there are some limitations we may need to accept.



> Why go to the extreme of converting the electricity to an inert gas then using that to push your vehicle. Damn you really need to see the reality of that.


Fast refillability and cost effective. No one is going to build or support a cost unsustainable infrastructure, especially when in relative terms that the cost of gas is so cheap that any alternative that's not in the ballpark isn't going to fly.

LN2 is already a widescale liquid that's an afterthough of other industrial gas processing. You can buy it off the shelf for less than 50 cents a gallon.

And to reiterate for the third time, this is not a replacement. It's the second component of a hybrid infrastructure for a plug in EV.



> If you need a vehicle with 100 mile range at freeway speeds then be sure you build or buy one that does that for you. If you need 300 miles then use a clean turbo diesel vehicle. It is truly the next best way to go a long distance for less. I guarantee our nitrogen system will leave you stranded far sooner than the battery vehicle or diesel vehicle.


As an enthusiast, cost is of no object to you. You cannot propose an infrastructure without doing a comparative cost analysis. Diesel is out because we're only having a discussion of all electric infrastructure. If diesel is in, then the problem is solved using current tech to put a plug in diesel/EV hybrid on the road and call it a day.

Here are the parameters:

1. 250+ mile range.
2. Refilling from empty to full in 15 minutes or less (I'll throw in an extra 5 minutes)
3. Per mile cost competive with gas/diesel at $2.50/gallon over a 5 year period. I'll allow for amortization of equipment over that time.
4. All electric with no petro in the loop.

It just cannot be all batteries. Not cost sustainable and no current tech will accept the nearly 100 kW of charge in that time period at anywhere near the price point. Diesel is out.
This is a think out of the box thread. Time to get to it.



> I will go further with the electricity used to convert nitrogen to a usage form than you will go after you do the cost factor for the conversion and then buying the nitrogen then driving how ever long you can go.


Did I not start with it's inefficient? This is a supplemental thread. The only reason for the discussion is fast refillability at a cost effective price point. The most efficient, and primary mechanism, is charging of batteries. But batteries cannot currently meet points 1,2 and 3 above all at the same time. So you have to supplement with something else that's cheap, even if it's inefficient.



> Go electric. Go direct. Use solar to a very large bank of batteries then use that bank to do fast charging. No other conversions needed. During the time no one is charging the charge from the solar will be banked in a huge battery to be utilized later and it will still be far more efficient. Building a Solar Electric Fast Charge Station like your typical Station is a very doable thing and even existing stations can ADD that to an existing system that caters to gassers that will still remain for a long time to come.


Price it out for me. Time it out for me. Do we have batteries that will accept that type of charge in the 10-15 minute timeframe that's cost effective? What's the cycle life going to be? Most LiFePo4 cells accept charge at 5C or less. That's why it takes hours to charge. How are you going to get that down to 15 minutes and keep the cost competitive?

I have no disagreement with you about augmenting existing stations. Side by side is how it'll get done. But like most consumers, I'm going to look at the sign with the price on it to decide if I'm going to buy. If gas cost me $50 to go 400 miles, and electricity cost me $16 to go 100 miles... If filling with gas takes 10 minutes, and filling with electricity takes an hour, then I'm not convinced as it costs more and is less convenient.


> I have been driving my Leaf since Last June on a daily basis to work and back and a few side trips too. I would not have purchased the car if it did not fit the needs. My Leaf is used literally for 99% of MY driving and when I do NEED to go further I DO take the ICE. Not an issue. It also only costs me $1.50 to go 45 miles. Guaranteed you won't be doing that in your nitrogen vehicle.


You are an enthusiast. I'm arguing this from the perspective of an average ordinary user. So unfortunately, I'm going to have to pick apart your analysis:

1. The only discussion we are having is the 1% that the Leaf does not cover. While I wish that we could convince the populace that 99% is good enough, it's not. The only argument you will get from them is that if their mother calls and says come now, and she lives 150 miles away, the car won't get it done. It's a perception problem, and most of us are way to invested to see it. No ordinary person is going to drive home, and pick up the ICE. No ordinary person is going to call a cab. An ordinary person will hop in their car, even if the gas light is on, and start driving toward their mother. They will stop, get gas in 5 minutes, and keep moving. This situation and how people feel about it is the only reason we continue to have range extension discussions. Ordinary people already have a set expectation of their vehicle, and any challenger that isn't better and cheaper in virtually every area isn't going to get traction.

2. Does the $1.50 include the price of the charging station? From Nissan's site that $2K in cost. How do you amortize that? Also how much is the battery replacement? How do you amortize that too?

3. Charging at 120V takes 20 hours, 7 hours at 240V. This entire discussion is what happens when the car is on E due to unforseen circumstances. 

4. The 480V quick charge is a step in the right direction. However, it's still 30 minutes, it only gets you an 80% charge, and it's unclear how much such a charge will cost, or where you can get it.

People switch because something is better or cheaper, not out of a sense of nobility. I'm wondering what will happen with the Leaf once the enthusiast market gets its fill.


> I feel the same about any type of fuel cell too. They work but using electricity to convert is poorly used when that power could be banked in a battery for direct charging to a battery is the best way. The fuel cell vehicle can't really go any further than a good well built electric vehicle anyway and its way cheaper and available NOW.


Fuel cells use petro, so it's off my list.

I know that I'm being stubborn, but we are really discussing infrastructure sea change here. While limitations and high overall costs work in an enthusiast market, it will not fly with regular consumers. Just believing isn't going to be enough to get a large number of people to convert. People want a tangible return for switching.

Say for the sake of argument you have the Leaf, and you outfit it with an LN2 dewar, radiator, and air turbine and the LN2 filling infrastructure exists. In the emergency with the proverbial mother, one would hop in the car and start driving on the remaining electricity and using the LN2 that's in the tank. Before both run out, stop in a station, take as much of a fast charge as you can get in 5 minutes along with a full tank of LN2, and keep it moving.

It closes that 1% gap and does it in a cost effective way. Which is the objective.

ga2500ev


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## ga2500ev (Apr 20, 2008)

drgrieve said:


> When we are driving 500 kwh packs (2000 miles) and charging at 250 kwh (150 mile per 10 minutes) these sort of discussions become fairly moot. (possibly sooner than you think!)
> 
> In the end we'll be back to large SUV's and trading reverse air con for resistive heaters and using DC motors over AC.
> 
> ...


How much will it cost? At $4 with a 25 MPG car, the base fuel cost is $0.16 USD a mile. How much will this 500 kwh pack cost? How much to replace? How much for the infrastructure?

Saying that the point is moot is like saying that soon commericial flights into space will soon be moot. You can do it. But it'll cost you $200K USD for the privilege.

ga2500ev


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## ga2500ev (Apr 20, 2008)

gottdi said:


> Before we go any further, show me the cost to fill the extremely large cyro bottle and show me how far your vehicle can go at 55 mph average speed before needing to be refilled?


Now that's a fair question. The conclusion of this paper from the U. Washington Cryocar guys is used as a reference.



> CONCLUSION
> 
> The potential for utilizing the available energy of
> liquid nitrogen for automotive propulsion looks very
> ...


Several quoted LN2 prices shows LN2 prices in ranges from 6 to 11 cents a liter. I'm going to arbitrarily pick 10 cents for discussion. The reference vehicle from the Cryocar paper is a 1991 Honda CRX with an estimated power requirement of 7.8 kW to maintain a 60 MPH cruising speed. Note that the given setup can provide twice that amount of power in ambient temp with the given consumption. This is specifically a zero emissions setup, as specified by my list of parameters. Much greater possible efficiencies are possible if petro is allowed to be used to further heat the expanded nitrogen gas past ambient.

OK. The base conversion is that a 50 gallon LN2 tank gets you 86 miles for a cost of $5. So the cost comes in at about 6 cents a mile for the LN2.

Note that the U Washington guys were trying to define an LN2 only car. In my proposed setup it would be a hybrid range extension coupled with a traditional plug in battery pack. At 15 kW, the setup would in theory be able to power the car and recharge the batteries at the same time.

Hope this helps.

ga2500ev


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## DanGT86 (Jan 1, 2011)

Interesting discussion. I find it funny how much thought and effort goes into designing a better hybrid. Just talking to people since I got into EVs, it has become apparent that the 1% of situations that make an EV less desirable are enough to keep 99% of people from driving one. 

I often try to stress to critics that if I ride with someone else or bike to a location I would have to go home and get my ICE vehicle to answer and emergency 150 miles away. Life does not always lend it self to drop of a hat cross country journeys no matter what we drive. Complaining that my EV cant go cross county is like getting mad at my toaster for not being a lawnmower.

Its all about infrastructure. I wish hybrid and perpetual motion dreamers could devote more time and energy to activism regarding EV charging infrastructure rather than chasing expensive complex diy hybrid drives.

I personally like the idea of interchangeable standardized battery packs. You buy the energy but the utility or fuel company can own the pack. Pull up to the filling station, packs get switched out in minutes/seconds and off you go. Unfortunately the cost of batteries vs electricity per kwh makes this a pretty bad deal for the filling station.


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## Ziggythewiz (May 16, 2010)

DanGT86 said:


> Complaining that my EV cant go cross county is like getting mad at my toaster for not being a lawnmower.


But what if you get hungry while mowing the lawn? You really shouldn't have to tow the mower to the garage and walk into the house when a better equipped vehicle could take care of all your needs on the spot.



DanGT86 said:


> I personally like the idea of interchangeable standardized battery packs. You buy the energy but the utility or fuel company can own the pack. Pull up to the filling station, packs get switched out in minutes/seconds and off you go. Unfortunately the cost of batteries vs electricity per kwh makes this a pretty bad deal for the filling station.


Funny you don't like people wasting time on complex hybrid ideas but you endorse the biggest waste of time in the EV industry. A car lease is expensive and inefficient. A battery lease is much worse. I've heard quotes for a 1 year lease for $2000. Yeah, that really saves money at the pump.


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## ga2500ev (Apr 20, 2008)

DanGT86 said:


> Interesting discussion. I find it funny how much thought and effort goes into designing a better hybrid. Just talking to people since I got into EVs, it has become apparent that the 1% of situations that make an EV less desirable are enough to keep 99% of people from driving one.


That's why I keep saying this is a perception problem. Present something new, and the first thing the average person does is figure out how it doesn't fit into their current world view. Many people treat a car as an extension of their personality. Flaws do not fit well in that model.



> I often try to stress to critics that if I ride with someone else or bike to a location I would have to go home and get my ICE vehicle to answer and emergency 150 miles away. Life does not always lend it self to drop of a hat cross country journeys no matter what we drive. Complaining that my EV cant go cross county is like getting mad at my toaster for not being a lawnmower.


Except that it's not, because there was no previous expectation that the toaster can cut grass. We're talking about replacing people's cars. There is a well established expectation of what a car does. Anything that doesn't meet that expectation can forget it.



> Its all about infrastructure. I wish hybrid and perpetual motion dreamers could devote more time and energy to activism regarding EV charging infrastructure rather than chasing expensive complex diy hybrid drives.


I'm in perfect agreement with this. If you look at my other posts, I push how we can make EVs better than gas vehicles: wireless charging while moving. I meet resistance with this idea just like the LN2 because it isn't efficient. But it's the perception. Tell people that they never have to pull into a station again, and now you have their attention. As always it's a part of an all of the above strategy along with fast charging stations. But there are few vehicles that spend time off road. Electrify the roads, and most of the rationale against EVs disappears.


> I personally like the idea of interchangeable standardized battery packs. You buy the energy but the utility or fuel company can own the pack. Pull up to the filling station, packs get switched out in minutes/seconds and off you go. Unfortunately the cost of batteries vs electricity per kwh makes this a pretty bad deal for the filling station.


I cannot imagine the insurance liability of such a scheme. Or the potential for theft. Who pays when the packs fail out on the road? Who gets to define the standard?

Lots of questions in that direction. However, have you taken a look at flow batteries? Similar idea except that the infrastructure of the battery stays in the car while the liquid electrolyte(s) are pumped in/out at the station. Spent electrolyte can be recharged at the station, while the user drives on with charged electrolyte. The size of the electrolyte tanks define the capacity of the battery while the structure of the cells define the power capability. So small capacity power batteries and large capacity limited power batteries are both possibilities. In addition the electrolyte can be recharged _in situ_ at a standard charging station. So you can get fast refillability along with plug in charging capability. It has the possibility of being a single structure "hybrid".

ga2500ev


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## ga2500ev (Apr 20, 2008)

gottdi said:


> Now one last thing. If you are 150 miles away from someone else having an emergency you DO have time to go get your ICE. For them, they need to call 911. You take your time and drive safely. Piss poor excuse.


Pete,

We're never going to agree on this because you are dealing with the reality of the situation, while I'm talking about the emotion and the perception of it. The one thing I've learned in the real world is that most people make decisions (and usually bad ones) with their emotions. Whether it's a piss poor excuse or not, when many hear about the range limitations and the charging times, they will dismiss it out of hand because they will be required to think and plan instead of having the convenience of a 5 minute fill up on every corner.

I think it's time to put this one back to bed. The true reality is that until peak oil truly comes around and supplies dwindle, that no group has the political, financial, and emotional will to effect change. Unless there is a mandate for 10-15% ZEVs, and the will to stick to it, there will never be any traction on any of these ideas.

Nothing is going to stop the range extension/hybrid questions. I've been here 4 years, and they pop up every couple of months. We pitch the same answers (get more batteries, plan, have a second vehicle). But the very fact that the question continues to be asked proves my point that emotion rules over logic. I agree that 99% of daily driving is taken care of by EVs, and that if we can get the populace to embrace them, we can break oil dependency forever. But in order to do that, they will need to be either guided to that decision by mandate, or be convinced they cannot live without an EV. In order to do the second, you do not try to convince the customer they are wrong. That's how you lose customers. You find a way to plug the hole in their perception until they see that it's wrong to begin with.

So my conclusion (and I promise this is my last post on the subject) is that some non oil based hybrid tech will have to be embraced, and it has to cheap in order to compete with the competition.

In the end we're simply going to lose to standard hybrids. Car companies get customers. In a gas hybrid, they sell a gas car with the perception that it's an EV. The point is a hybrid is a car that does everything that a car is perceived to do.

If you want EVs to win, find a way to do the same thing. Make it better. Make it cheaper. Make it more convenient, not less.

We no longer have a tech problem. We have a marketing problem.

Adios!

ga2500ev


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## ga2500ev (Apr 20, 2008)

gottdi said:


> No, no you don't get to go away yet.


Ok. Since I've been invited back.



> I am and have been fully aware that people make crappy decisions on emotion (ego) and it is what drives the market. The market folks know it and run with it. It is how the game is played. Getting traction is going to take time. I will never disagree there. One little conversion at a time. It will happen. Actually hybrid vehicles are fine but they must be shown to be practical. Electric/Petrol has shown to be practical because you don't have to plug them in. It's done right on board except for the Volt and some Prius because you can plug those in now.
> 
> I am not intending to try to prove the customer wrong. I am just showing them a better way and it IS better. They just don't see it yet.
> 
> A true Hybrid will be the best of both. Most hybrids today are only a marketing ploy and not even considered a hybrid in my view. Felt that way even before I purchased my Leaf.


We definitely agree on this. Since they are not generally plug in, and they cannot function without gas, I find the term hybrid is a stretch. In my head I treat them as an gas vehicle with E-assist.



> The Volt is the Most Hybrid of them all. It IS in the right direction and yes, many folks WILL need a good hybrid over straight electric. I am even thinking of getting a Volt for those times we need to run long errands or to go visit in the mountain or in the Bay area.


Agree again here. The Volt has an all electric mode that has 30+ miles of range. The Volt is also plug in. It is a step in the right direction. GM's mistake is thinking that consumers are willing to pay a premium price for it. The $40k USD price tag makes it difficult to market. It looks like the midsize hybrids (Camry, Optimum, Fusion) are in the mid $20K ballpark. A plug in, electric only mode, hybrid in this ballpark would be a winner.




> I just don't think your nitrogen hybrid idea will stand strong. It really is no better than fuel if you look a bit deeper. On the surface it could be marketed as a cheap source and a non polluting source but it won't stand.
> Once the makers of the process realize the the waste nitrogen has a valuable market the price WILL skyrocket. You know how greedy people get. They will squeeze you dry as a bone then leave you to crumble in the desert sun.


But here's where it gets good. It's a market that cannot be monoplized. Anyone can make LN2. All it takes is air, electricity and a compressor to make. It's the open source of energy carriers. So if the process guys try to squeeze the price, people will come in and undercut them. On the usage end, while highly efficient setups can be created, a simple setup with a LN2 pump, a radiator/water pump for an expander, and an air turbine, is all that's required to regenerate power. Here's a blog post that discusses how to use surplus lab equipment to DIY generate about a liter a day. It's scalable too.


> Electric will take hold once those guys figure out how to market and squeeze you dry.


I think it's a market that is too elastic to respond to such tricks. Of course it's all hypothetical anyway. A long time ago I wandered into this thread and pointed out that LN2 would give better range than compressed air, and has the ability to create fast refillable ZEV and LEV (emissions, not electric) hybrids without breaking the bank. It's all theory. I would like to see one going though.

ga2500ev


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## Ziggythewiz (May 16, 2010)

ga2500ev said:


> It's all theory. I would like to see one going though.


If it's a winner over BEV, it shouldn't be that tough for you to make one.


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## ga2500ev (Apr 20, 2008)

Ziggythewiz said:


> If it's a winner over BEV, it shouldn't be that tough for you to make one.


I don't think it's a winner over BEV in a head to head comparison. I think it needs to be a hybrid with BEV. From a power density and efficiency standpoint, nothing is better than batteries in the electric realm. So all EVs need to start with batteries, end of discussion.

The question is supplemental as the title of the thread states. In that arena we need to look to the areas where batteries are weak: cost and refillability. Finally if we want to stay in the EV only realm, and I know that I do, we need to figure out an energy carrier that can quickly be refilled, and won't break the bank. 

ga2500ev


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## Ziggythewiz (May 16, 2010)

Obviously the easiest way to increase the range of a BEV is with more B. If you want to make it hybrid you would need an incredibly cheap and simple alternative to beat either additional batteries or the traditional ICE generator approach.


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## Duncan (Dec 8, 2008)

ga2500ev said:


> I don't think it's a winner over BEV in a head to head comparison. I think it needs to be a hybrid with BEV. From a power density and efficiency standpoint, nothing is better than batteries in the electric realm. So all EVs need to start with batteries, end of discussion.
> 
> The question is supplemental as the title of the thread states. In that arena we need to look to the areas where batteries are weak: cost and refillability. Finally if we want to stay in the EV only realm, and I know that I do, we need to figure out an energy carrier that can quickly be refilled, and won't break the bank.
> 
> ga2500ev


OK lets look at some numbers

Liquid Nitrogen Power

The idea is that liquid nitrogen is vaporised and the resultant high pressure gas is used to operate an air motor
The absolute maximum power is set by the vapour pressure but the engineering power is set by the working pressure,

Lets say we can operate at 200Bar – the power numbers become the same as a 200 Bar compressed air car

100liters (80Kg) will give ~ 30Kwhours

In order to get this power out of the liquid nitrogen we need to draw heat from the surrounding atmosphere –
The same way that an IC car dumps waste heat
This means that we will still need the heat exchange “stuff” from an IC car 
There is a problem here – frost build up in the heat exchangers
Performance when cold or humid………

Anyway


IC engine car
Engine – 200Kg
Heat Exchangers – 100Kg
Fuel tank – 100Kg
Total – 400Kg – 300 miles range

Electric Car
Motor/controller – 100Kg
Batteries - 600Kg – 60Kwhrs
Total 700Kg – 200 miles range

N2 Car
Motor – 200Kg
Heat Exchangers – 100Kg
Fuel (N2) 200 litres – 200Kg
Cryogenic tank – 100Kg
Total 600Kg – 200 miles range

Charging 
Home Charger
5Kw – 12 hour charge - $4000


Home N2 system
Cryogenics + tankage + filling system 
5Kw – 16 hour charge - $40,000 (at least)


Fast Charge – at fuel station
N2 - Cryogenics + tankage + filling system - $400,000
Filling time, time to pump 200 liters of liquid nitrogen into your tank 20 minutes

Electrics
Storage battery, high voltage fast charge – 3C rate - $50,000 
Charging time 20 minutes

Neither is like pumping 60 liters of petrol – both will take 30 minutes – 
after driving for 200 miles I feel like a break and I would rather other road users took a break at least as frequently



In your comments you said that it was not possible with current technology to charge a BEV in 20 minutes


Not so my friend - there are cells that can be charged at 5C - 12 minutes


Now you do need a large power supply - but that's what the service station battery is for - it is charged slowly and used to dump power into the customers cars 

A 60Kwhr pack at 5C is 300Kw - no problem for the service stations 300Kwhr storage pack - weight is not important - used BEV packs ....


The main issue is that a Nitrogen car is fixing a problem that does not exist - instead of having a liquid nitrogen station you would simply have a fast charge station


Now - look at the efficiencies !!!!! 

I would not expect a mains to wheels efficiency of greater than 10% on a liquid nitrogen system


It is possible to get some liquid nitrogen cheaply - but this is as a byproduct of liquid oxygen manufacture.
There is some available - when it is used the price will rise enormously before the supply increases


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## nulluser (Mar 4, 2012)

ga2500ev said:


> There is a single failure mode that drives all of these discussions Pete: what do you do when you run out of energy? There's nothing about "Buy some extra batteries." that solves that issue because no matter how many cells you have in your pack, when they are empty, you are stuck.
> 
> ga2500ev


You could drive a turbine with the gas station's compressed air and use a generator to charge the batteries. No tank needed.

That is roughly the same level of efficiency (very poor).


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## ga2500ev (Apr 20, 2008)

Ziggythewiz said:


> Obviously the easiest way to increase the range of a BEV is with more B. If you want to make it hybrid you would need an incredibly cheap and simple alternative to beat either additional batteries or the traditional ICE generator approach.


When you can fully charge B in 5 minutes, I promise I will stop talking. When you can make B cheaper, again I will stop talking. Neither of these are the case now.

I'm currently driving a 20 YO Infiniti with a 12+ gallon tank. Gets 360 miles on that tank and takes 5 minutes to fill. Spec me out a B only system that does the same that isn't going to run in the Tesla range of price.

This is not just an issue of increasing range. If it were we wouldn't really need to have this discussion. It's a juggling act: increase range, fast energy transfer, limited cost.

Everything loses to gas because of its incredible energy capacity, ultra fast refillability, and relatively cheap price. 12 gallons of gas is equivalent to a 132 kW battery (taking 33% efficiency into account) that can be transferred in 5 minutes. Flatly put, there's no way to do that with only B and stay in the roughly $2100/yr range that the gas costs (1 tank per week @ $3.50/gallon).

That is the competition. B need not bother to apply. It cannot compete on price, refillability, and is difficult to pull off the range. The Leaf has a range of 100 miles or so. Why not 300? The Leaf fastest charge @ 480V is 30 minutes, and that's only to 80% capacity. Why not 5 minutes and 100% capacity? Batteries have limitations. For batteries only to work, it has to compete with gas. And that's a hard bar to reach.

Now electricity can compete. It's a hands down winner on price and efficiency. That same 132 kW only cost $20 at $0.15/kW (which is a premium price, off peak is much cheaper) as opposed to the nearly $44 for the 12 gallons of gas. But putting $20 of energy in a $53k (2640 A123 20 Ah prismatic pouches at $20/cell) battery pack isn't really gonna work. We need a cheaper carrier.

I have to run. I'll come back with LN2 numbers in a bit.

ga2500ev


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## Chad (Aug 1, 2008)

I just wanted to point out that a charge rate of 1C means 1 * Capacity. That would mean that a charge rate of 1C allows you to stuff enough power into the batteries to have them charged in 1 hour. A charge rate of 5C will allow you to charge in 1/5 of an hour. You just need to have enough power to stuff in that fast.

My R/C LiPo's have a charge rate of 2C and I charge them up from 80% DOD in 30 minutes. They are only 7.4v and 5.8aH, but if they where 172v and 200aH I could still charge them in 30 minutes. I would just need a 68.8 kW charger instead of the 86W I am using now.

At 5C charge capability, if you had the power available you would be all topped off in about 12 minutes. You just need a lot of power available in a very short time.

My thought would be unattainable as it would require co-operation between industries. . .

Build a standardized battery. (a few different sizes of course, AAA, AA, C, D maybe  ) Make it flat and strap to the bottom center of the car. You would sign on to a lease type program and rent your battery. When you need to "fill up" you can pull into the "gas station" which would be just like those minute lube oil change places. Pull onto a lift (or over a pit) where they would disconnect your battery and put in a fully charged one. The swap should only take 10-15 minutes.

It would be much the same as the way everyone deals with small propane tanks now, you don't own the tank, you sign on to the program and just trade in your empty one for a full one, and pay for the propane.


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## Chad (Aug 1, 2008)

I just want to make one more point about always comparing to gas. Gas is a fossil fuel and we want to get away from that.

I think the world forgot along the way that things have a certain cost, and the only way North America has made things cheap is by externalizing the cost.

here is some info on what I mean about externalizing costs http://www.youtube.com/watch?v=gLBE5QAYXp8


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## Ziggythewiz (May 16, 2010)

The world doesn't care about external costs. The phrase doesn't even have a place in a capitalist society. The only ones who care about externalities are truly altruistic socialists.


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## Chad (Aug 1, 2008)

Ziggythewiz said:


> The world doesn't care about external costs.


I bet the coffee bean, sugar cane, and coco bean slaves do. . .


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## DanGT86 (Jan 1, 2011)

Did anyone notice that in the diy LN generator blog post the author says that it requires 8.5kwh to get 1L of nitrogen? I know it was just a proof of concept idea but that sounds terribly expensive. Unless decompression of one L through a turbine would do way more work than I am giving it credit for


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## aeroscott (Jan 5, 2008)

Ziggythewiz said:


> The world doesn't care about external costs. The phrase doesn't even have a place in a capitalist society. The only ones who care about externalities are truly altruistic socialists.


In a capitalistic enterprise they care very much about keeping externalities external .In fact they spend large amounts of $ making internal costs into externalities . One example is a large power user getting kwh's for far less then the retail home owner .


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## aeroscott (Jan 5, 2008)

Duncan said:


> Ok lets look at the numbers
> 
> Assume perfect compression/expansion
> 1m3 (1000litres) air tank
> ...


since LN2 is 700 atm expansion thats 3.5 X 25Kwhrs=87Kwhrs / 100 liquid liters (25 gallons + insulation ) If the refrigeration can be about 75% eff. for -300 deg. f. should be able to get >75% on the motor side with 2 to 3 stage turbo chargers coupled to pm motors .Then you have a very effective storage system . Granted not in the league of lithium eff, but close to the eff. of lead acid at much lower weight . I would charge up the lithiums then start up my 3 stage industrial surplus air liquifer and fill a huge 500 gallon cryo tank . thats 1.7meg watts capacity (2.4 meg watts input) , a great fire fighting system , all kinds of cold ,cryo treating steels, nitrogen for my car tires ,nitrogen for plasma cutter (better then air ,no oxcidition) lets see @ $.33/watt for the lithium its only $560,000 . for my off grid low capital system, I need money not brains. I have/had most of the parts , lost my 25hp 3 stage Ingersal Rand air compressor in a fire .


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