Need Help With Pneumatic Battery

[happy_hipster]

Im not talking about a perpetual motion machine, here folks. And I agree, in part, that I am not the first one to think of this. In fact, the paper I posted by someone who knows much more then me shows not that Im deluding myself, but that I'm onto something. Sure, I will give you that the efficiency is not up to your standards(yet) but if you are talking about a week a year retreat or a day a month offgrid Bnb, efficiency IS NOT AN ISSUE. What is an issue is if It can provide the power necessary for the time necessary.

All of your thermodynamics excuses are just saying you cant take power and put in in a batter for later use. I've seen models of using concrete blocks lifted 1000ft in the air to store power. Just because the research is putting power into chemicals does not mean that is the most cost effective over time way to do it. It means that is the direction people are being pointed in.

It still falls into the category of "If people could fly we'd a dun it already"

[peakbagger]

BTW my bet it on the concrete block approach over pneumatic The wire to wire on the block approach seems to be pretty attractive.

[J.P.M.]

All of your thermodynamics excuses are just saying you cant take power and put in in a batter for later use. I've seen models of using concrete blocks lifted 1000ft in the air to store power. Just because the research is putting power into chemicals does not mean that is the most cost effective over time way to do it. It means that is the direction people are being pointed in.

It still falls into the category of "If people could fly we'd a dun it already"

Suit yourself. Opinions vary, but to call Thermodynamic principles an excuse does little more than put your ignorance on display. But I've called out your ignorance in that area enough.

As for storing anything, an electrical "battery" (a battery of electrical "cells" that is) stores work, which is defined as moving a force through a distance. These days work is pretty much synonymous with the word energy. You'll be less ignorant if/when you take the time and make the effort you learn the difference between work and power, which is the time rate of doing work (or expending energy).

If I was to say an electrical battery can't store energy, I'd be denying reality.

While not necessarily speaking for Peakbagger, what we're saying is that the (potential) energy released by the partial expansion of a gas - while having some advantages - is thermodynamically inefficient compared to other methods of using stored (that is, potential) energy.

The elevated block example you cite - and similar to a water reservoir BTW - is no more than an example of potential energy storage by virtue of elevation difference in a gravity field. That's what powers my tall case clock.

Work stored by virtue of such elevation can be quite a bit more efficient than expansion work done by a gas, the expansion of which is a good textbook example - along with friction - of a process which produces a large increase in entropy - an efficiency killer.

[Bala]

I started on a response with an example of how much energy it would take to compress a qty of air to 3000psi and then how much electricity that would generate using an air motor but decided that Happy Hipster would ignore it anyway.

[chrisski]

I started on a response with an example of how much energy it would take to compress a qty of air to 3000psi and then how much electricity that would generate using an air motor but decided that Happy Hipster would ignore it anyway.

Well if you’ve done the work already, I’d like to know.

We used to have a portable compressor to charge Scuba Tanks at work. Certainly was not electric and used a gas motor. Another place I’d charge tanks used a gas motor also. I’ve found that when items are run off gas and not electricity, its because they use a lot of power, more than electricity can easily provide (This translates to no longer 120 volt powered, and need to go to 240 at least). I doubt the energy put into charging a 80 cu ft tank to 3000 PSI is anything close to the energy that comes out of it, even if you were to take a hammer and knock the valve off creating a missile.

I never thought about the energy lost to heating and cooling.

[J.P.M.]

I started on a response with an example of how much energy it would take to compress a qty of air to 3000psi and then how much electricity that would generate using an air motor but decided that Happy Hipster would ignore it anyway.

How efficient the process you describe would be will depend on, among other things when and how much heat was removed from the air in the tank after compression but before expansion, and the (in)efficiencies of the equipment. That's a Thermodynamics 101 homework problem.

[Bala]

I just looked for air motors and found one that will provide 1kw. It requires 1750 lpm ( Litres Per minute) of air to do so.

Looking at a small handyman compressor with a 1kw motor it will make approx 160 lpm, so not even close to driving the 1kw air motor

The bauer small dive compressor will pump to 3000psi, I have a petrol one but the electric one is listed with a 2kw motor and listed at 3.5 lpm. It takes an hr to fill a scuba tank to 3000psi from empty and that scuba tank full of air would not drive that 1kw air motor for long enough to anything meaningful, if at all.

You also have a big maintenance factor in making, storing and using compressed air.

I just dont have the time or need to work out the specifics of what would be needed to make enough air and store it to make electricity when I know its pointless.

[J.P.M.]

I just looked for air motors and found one that will provide 1kw. It requires 1750 lpm ( Litres Per minute) of air to do so.

Looking at a small handyman compressor with a 1kw motor it will make approx 160 lpm, so not even close to driving the 1kw air motor

The bauer small dive compressor will pump to 3000psi, I have a petrol one but the electric one is listed with a 2kw motor and listed at 3.5 lpm. It takes an hr to fill a scuba tank to 3000psi from empty and that scuba tank full of air would not drive that 1kw air motor for long enough to anything meaningful, if at all.

You also have a big maintenance factor in making, storing and using compressed air.

I just dont have the time or need to work out the specifics of what would be needed to make enough air and store it to make electricity when I know its pointless.

All that is a practical Q.E.D. to what I've been saying throughout this thread.

With knowledge of Thermodynamics you can prove it to yourself. I prefer the independence to peddler's hype.

[happy_hipster]

Thank you for exploring this a little further. I really do appreciate it. It really makes no sense just in saying it wont work and going on. It also makes no sense in just calling me names and trying to bully me into discounting everything. Claiming that the model of the raised weights is more efficient helps, but what it does not do is concentrate the energy. The reason chemical batteries are so popular(besides temporary efficiency) is that they are portable and upgradable. Chemistry is cool like that. Compact. Somewhat lightweight. No moving parts.

But the R&D has gone into it, and is going into it. I have heard of cars that run on compressed air. To me, the next step would be homes, and then cities.

We did not see the first airplane work and then abandon it because trains were more efficient. Same thing here. We just need to refine the compressors and motors and heat exchangers and cooling systems to make it more efficient. Thank you all for taking a moment of your valuable time to consider and debate my seemingly pointless observations.

However more efficient, chemical batteries are toxic, explosive and temporary and I do not like or condone them in any way. We need to explore all and any alternatives.

[happy_hipster]

It is also interesting to think about how an idea such as this could change how we think about space. Being that different gasses liquify at different pressures, it would be a good way to transport breathable air, store energy, and remove unwanted gasses from the enclosed environment. Not only could liquified gasses be used to recapture energy in the form of electrical generation, but also be used to vent unwanted gasses as thrust for the craft.

[J.P.M.]

It is also interesting to think about how an idea such as this could change how we think about space. Being that different gasses liquify at different pressures, it would be a good way to transport breathable air, store energy, and remove unwanted gasses from the enclosed environment. Not only could liquified gasses be used to recapture energy in the form of electrical generation, but also be used to vent unwanted gasses as thrust for the craft.

I can happily deal with ignorance, and persistence in opinion is a virtue I appreciate, but ignorance with no inclination to learn or investigate reality is hard to overcome, especially when combined with argumentation with no purpose other than that of argument.

Enjoy your ego and intransigence in the face of experience and training.

Something I was made to memorize in high school comes to mind:

"During my 87 years I have witnessed a whole succession of technological revolutions. But none of them has done away with the need for character in the individual or the ability to think."
Bernard Baruch, American Businessman.

I'm outa' this thread.

[Mike90250]

Compressed air cars:

https://www.popularmechanics.com/cars/hybrid-electric/a5923/compressed-air-car-myth/