Pneumatic Power Grid for Small Scale Energy?

Don't they do something like this already with those little solar powered garden lights?

http://www.amazon.com/s?ie=UTF8&keywords=solar%20power%20garden%20light&page=1&rh=n%3A1055398%2Ck%3Asolar%20power%20garden%20light

I don't see why you couldn't use the same principle for other small local jobs.

"However if you are in a situation in which you can afford to throw away the energy created by your solar cells or windmill (both ordinarily quite expensive for the power produced) then the losses inherent in pneumatic systems might not be a concern. Likewise, if the work done is very small, these losses may be of no practical significance." I think you hit the nail on the head. I linked to some guys flap turbine http://www.youtube.com/watch?v=Ue7PkOkDD-M and http://www.youtube.com/watch?v=AX4EN-HZNEg Now as far as I am concerned, that is great work. but for electicity it will only work at certain speeds. And if he converts the energy to electricity, it is an extra 150 bux minimum for batteries and charge controllers and he has to use it as it comes in. If he links to the grid, it is what, 500 dollars? To send in 5 or 10 dollars worth of electricity per year! So on either scale in the videos, it is just a useless piece of entertainment. But if he has a little pneumatic system in his back yard at 1 or 2 or 3 psi, it can oxygenate his pond or pump water around his garden beds or aquaponics or hydroponics system or greenhouse. (and all for next to to nothing). And it is somewhat of a fail safe measure. If the grid goes, earthquake or storm or something, even if his wind turbine gets knocked out ,he can hook this pneumatic grid up to a solar panel/air pump combo or some little contraption in a stream and it still all works and keeps his food growing or pond feature running. Maybe the prepper people would be interested? I have stayed in a few off grid places, it is a different world. Maybe a mix of pneumatic and small off grid grid would work for some people? Thanks for the comment, Brian

Excellent response.

Not sure where you are getting your "100 bux" figure from to get power 65 feet.

Around here you can buy a 50' extension cord for less than $15 and a second 15' one for about $5. In my book that says you can easily get at least 1000 watts of power over there on a 120 volt circuit for less than $20.

I have to put it under the ground in a pipe to code because it is long term. Code is 3 individual wires now. so instead of pulling an extension cord , I gotta pull 3 wires. I don't want to give the insurance company any excuse if I have a fire. It cost 600 dollars to bring the other shed up to code (and that was with me digging for the pipes). The Wire to the shed was hung up at about 7 ft in the air. So the issue is more insurance than anything. The sellers lost this amount off + the digging cost from their sale price. If it was all temporary, and just me living here, I would be all for the extension cords. I have to build a few retaining walls in the path too and cut some concrete pad out of the way as well. Really, I hardly use that little shed, and the other one is workshop with everything.

Thanks Brian

So you are saying your insurance company wont let you have an extension cord in your yard to do what you please with it for as long as you please as well?

What outrageous joke/scam of an insurance company do you have any way?

As far as running a common extension cord under ground goes just go buy some cheap plastic poly pipe at the local hardware store and stick it in that and bury it. As long as it still has a physical plug that goes into a wall outlet for its power source its still an extension cord and not permanently installed outdoor wiring.

It is unsafe to leave it for months or years over a concrete pathway and a lawn that other people use and other people might mow. I think you are focusing on the wrong issue, I would rather not wire that shed anyway. After all the person who wired my work shed lost a thousand bux on the sale price because of 1 hanging wire (not to code) from the house to shed. I am happy about that but not willing to repeat it.

If you're worried about running mains voltage through your yard, just use common low-voltage landscape lighting and pond pumps.

http://www.google.com/search?q=low+voltage+pond+pump

http://www.google.com/search?q=low+voltage+yard+lighting

I am not worried about it. I am not doing it, either high or low voltage because everywhere you want to do the pumping, you have to put a pump. Come spring, I will have about 6 pallet gardens to water outside and another 3 to 5 in the greenhouse. With this, you just need a 1/4 inch tube to pump water in each of those places. I was hoping for a discussion of the good and the bad of linking low efficiency low output local mickey mouse wind turbines, or tiny water power to little pneumatic systems to get some use out of them. Currently, none of this stuff is tried because everyone is totally obsessed with electricity (and the cost of linking it to the grid or storing the power is way too much). A pneumatic line has many of the features of an electrical line. You have line losses, you have air pressure and air speed (like voltage and current) and you can have a high pressure line or low pressure. You could even have something like alternating current if something oscillates the air in a tube. Britta Riley of Windowfarms noted in her second ted talk that they cut their carbon footprint by something like 50% by stitching from water pumps to low pressure bubble pumps. It might be worth investigating.

"... A pneumatic line has many of the features of an electrical line. You have line losses, you have air pressure and air speed (like voltage and current) and you can have a high pressure line or low pressure. You could even have something like alternating current if something oscillates the air in a tube. ..."

1. That's an absurdly simplistic comparison.

2. The reason for the repeated recommendations of electricity over pneumatics is EFFICIENCY, as explained in post #2.

In the 1870's Paris had a 50km reticulated air system around the city. It was used to run elevators, trams and was available to power small motors and sewing machines etc.

If needed the compressed air could run a small generator and provide the new fangled electricity.

I think New Scientist magazine had an article on it once.

"If needed the compressed air could run a small generator and provide the new fangled electricity."

Anybody want to do the math on that? I'm guessing something like 1000 watts in -> 10 watts out.

Pantaz, I am not sure what offended you. I grew up on a medium sized farm and the farm (10 inhabitants) was about the same size as the local town. (with around 1000 inhabitants). There was electricity everywhere in the town but on the farm that were places 800 meters from the nearest electrical socket. There are always places like that where the centralized infrastructure cannot reach for economic reasons. The only large scale use of low pressure air I know about is Windowfarms. Britta Riley said (in a ted talk) that when they went from water pumps to 1 psi bubble pumps, they halved their carbon footprint. That's the only efficiency figure I have. Sounds like a good one. If you can hook up a crappy farm built half assed wind turbine to a crappy farm built low pressure compressor half a mile away from the nearest socket and then use that compressed air to pump water up a pipe, (using 2 to 4 ft of the tube AS the pump!) why wouldn't you do it? By the way, electrical efficiency starts when they dig the coal out of the ground, so it is not as high as you seem to think.

Pantaz, I am not sure what offended you.

Nothing offended me. I simply offered a statement of fact.

The only large scale use of low pressure air I know about is Windowfarms.

I don't understand your view that Windowfarms are "large scale". Perhaps you meant they are a large seller of air pump systems. ($199.00 for a "one column" Windowfarm starter kit.)

Britta Riley said (in a ted talk) that when they went from water pumps to 1 psi bubble pumps, they halved their carbon footprint. That's the only efficiency figure I have. Sounds like a good one.

Unsupported assertion. The actual quote (from the video transcript) is, "It took building a whole bunch of systems to get it right, but once we did, we were able to cut our carbon footprint nearly in half." She offered no qualification for this claim.

BTW: She spoke at a "TEDx" event, not a formal TED conference. Worth reading: A letter to the TEDx community on TEDx and bad science. (I don't mean to imply that Britta Riley's presentation was "bad science". She is simply speaking from a layman's perspective.)


If you can hook up a crappy farm built half assed wind turbine to a crappy farm built low pressure compressor half a mile away from the nearest socket and then use that compressed air to pump water up a pipe, (using 2 to 4 ft of the tube AS the pump!) why wouldn't you do it?

If that's the level of work you want to put into it, go right ahead. But, that has no bearing on the poor efficiency of the system.

By the way, electrical efficiency starts when they dig the coal out of the ground, so it is not as high as you seem to think.

You're assuming the electricity is supplied by a coal-fired power plant. However, much of the discussion here talks about wind turbine generated power. So, yes, the efficiency can be quite high.

Not much to say to you. You are just one of those guys, you didn't offer a statement of fact. You offered an opinion. Here is some fact. Large scale, 38,000 registered members worldwide. http://our.windowfarms.org/2012/01/21/jalapeno-at-1-year-and-doing-some-pruning/

and

here it is a while after the pruning, so pepper into its second year and still producing lots of nice peppers for Tony's wife.

and low input Tony says"So what does this cost me? Let's say the pump runs at 1 watt. This is 0.001 kilowatts. The pump runs a total of 2 hours a day for me. That's 0.002 kilowatt-hours and I pay $0.10 a kilowatt-hr. That is only $0.0002 per day or $0.073 per year. That is insignificant! I probably have wasted more power in writing this email than what it costs to run my windowfarm for the year." As you can see, his windowfarm is made from coke bottles (which are not terribly expensive at all).

Brian

gaiatechnician,

You keep intermingling talking points. It makes for confusing and misleading communication. I include quotes within my replies to prevent such miscommunications -- unfortunately, that appears to be insufficient in your case.

Of course, my questioning your use of the phrase "large scale" certainly falls within the definition of personal opinion. That should be clear to anyone reading the paragraph. It is equally clear that that paragraph has nothing whatsoever to do with the larger conversation.

You may not like the facts I present, but the information is easily verifiable. If you (or anyone) can provide authoritative citations in opposition, please do. I will never claim to be infallible.

The subject of Windowfarms is tangent to this thread's OP, but it is definitely worthy of discussion. It is a terrific concept, and I applaud their success.

So for a honest scientific comparison what was the exact level of carbon output and where did it come from before and after they "halved it"?

I hate these types of overly generalized feel good enviro nutter comments that make things sound like they are really changing or affecting things for a measurable good.

If you want people to see a real change then give out real date related to real devices energies used and sources of what things where before and after so a honest comparison of what ever it is VS real life typical activities can be assessed to or by it.

Halving an already microscopic supposed but not confirmed carbon foot print really doesn't mean or count for much.

I welcome your answer to post no. 23 too. If Tony succeeds in growing 50 or 60 peppers over the winter in Chicago, for a dollar or 2 total, who is he hurting? And who can do that commercially for that cheap? Even with peer reviewed stuff, the reviewers do not generally have access to the raw data. (They just hope that the other person is honest). And, anyway, Riley employs scientist to work on the project, I am sure they vetted the work. One of the measurable goods is self reliance. As the arctic heats up, weather systems in middle latitudes are moving a lot slower. (that is peer reviewed research by the way). So even though middle latitudes are not heating up very much, a drought or heatwave or a heavy rain system is more likely to stick around for a week or two. That puts food supply for everybody at risk.

I hate these types of overly generalized feel good enviro nutter comments that make things sound like they are really changing or affecting things for a measurable good.

Likewise. Taken on one (slightly short-sighted) level, the simple act of growing vegetables is carbon negative, and measurably so. So you've got to wonder what carbon footprint she's talking about. The carbon costs of the nutrients? The carbon cost of shipping the seeds and nutrients? The carbon cost of running the pump? (Was the pump initially plugged in but now solar powered?) What about full life cycle costs? Soon, your body will convert some of the vegetables into methane gas, which is a far more powerful greenhouse gas than CO2.

Is she referring only to the electrical energy to run the pump? (Then it is easy to imagine that an overly-large centrifugal water pump [like an aquarium circulation pump] with any kind of flow control in line would be incredibly inefficient.) A particular bubbler (gas lift pump) could be more efficient, because it might be more appropriately sized. But that does not mean that bubbler pumps are more efficient than centrifugal or (especially) positive displacement pumps.

So perhaps what is being compared is pump sizing rather than pump type. But her statement is one of those that has no real meaning unless a lot of details are supplied.

A Leaf driver in North Dakota has a larger carbon footprint than a Toyota Prius driver in the same state. But I bet you can find Leaf drivers there (perhaps half of the 4 Leaf drivers in the sate) saying things like "I'm driving this to reduce my carbon footprint." Or "I'm driving this to conserve resources."

Why don't you just ask HER? I have emailed with her so I am sure a super smart engineer would get a prompt answer. So, again, why not just ask HER instead of THAT (Repeating an ignorant comment) and wasting a half a paragraph of spleen? You didn't back up your spleen with anything, by the way. Funny how that works? Is that ethical or honest or worthy of a great engineer like yourself? Your whole mode of argument is to put down the other person. I bet the guys who work, worked for you dispise you for that. But hey, you know it and you like it. What is your thoughts on Tonys peppers? So anyway, lets say 4 psi for pumping water 10 ft high with a home made wind turbine and compressor a mile from an electrical outlet. How cheap can that be built? I believe most of the energy lost in your 125 to 175 psi electrically run compressors are lost as heat at the compressors. This isn't the case at 4psi. Or is it better for your carbon footprint to be bluddy minded and run cable for a mile and use an electrical pump?

"I believe most of the energy lost in your 125 to 175 psi electrically run compressors are lost as heat at the compressors. This isn't the case at 4psi. Or is it better for your carbon footprint to be bluddy minded and run cable for a mile and use an electrical pump?"

I suggest you read up on pneumatic systems and pay close attention to the details of compressing gases and the math and energy levels that go with it. Energy transfer efficiency at 4 PSI is far far worse than that at 175 PSI. Same with long distance energy transfer.

A small high pressure line is far far more efficient than a large low pressure line. But neither can hold an efficiency candle to what a simple wire of even less size and cost to manufacture and install can carry.

As far as heat given off by highly compressing air its largly irrelevant. Once that high pressure air re expands back to normal air pressure levels it reabsorbs 100% of that thermal energy that it gave off in the initial compression stages.
http://www.engineeringtoolbox.com/horsepower-compressed-air-d_1363.html

"This isn't the case at 4psi. Or is it better for your carbon footprint to be bluddy minded and run cable for a mile and use an electrical pump?"

Again if you understood the math and physics and history behind compressed air energy transfer, storage and conversion you would fully understand why moving energy a 4 PSI air pressure for long distances with a hose or pipe Vs using high pressure or a simple battery or even just a small wire is not saving anything nor is it more efficient either.

The thing is its not that nobody has tried this but rather pneumatics is a well studied and understood science that has been studied experimented with tested and proven going back well into the 1600's and much of that is with designs that we recognize and still use today.

http://inventors.about.com/library/inventors/bl_otto_von_guericke.htm

(Repeating an ignorant comment)

I frequently repeat a portion of a post, (and italicize it) so that others know to what point I am responding. I did not find the comment "ignorant". It simply expressed an opinion with which I agree.

I don't feel a need to respond to your sarcasm and personal attacks.

Of course it's not efficient, but if you only want to run a small radio it may be tolerable.

About the same time Melbourne (Australia) also had a steam powered compressed high pressure water system, originally installed for fire fighting, that was used to power elevators.

Thanks for the link! http://en.wikipedia.org/wiki/Pneumatic_tube They used tubes for transport of mail for a while and they may still be in use in the house of commons England. There is a company in Ontario that is still in business making systems for hospitals, etc. Also found a youtube video from a guy who wants a high pressure north American super grid with renewable energy fed into the grid by compressing air and the pressurised air being both the battery and transport mode for the energy. Kind of like a back up system if the electrical grid goes down, I guess. (We know the grid is a big target for foreign computer viruses so might not be a bad idea).

http://en.wikipedia.org/wiki/Pneumatics has a link to pneumatic logic. (I went to the link but cannot say I understood any of it. I doubt that anyone tried to do useful stuff with 1 or 2 psi before. I washed sand from a river with 4 psi years ago. Just a test run but it got all the silt out of it and I made a small garden wall from the sand. I checked a bunch of other links but don't think there is anything on really low pressure systems. Brian

I think it could definitely be an alternative. For the house even though most of us use electrical power we actually need mechanical and thermal power for everyday activity and with a pneumatic system you can get both. You can even have refrigeration up to a certain level only using air compression. The power density is what cheap pneumatic systems lack.

A big problem is with the storage of energy in form of compressed air. It is quite low in energy density. Better to use hydrostatic storage.

Also using solar panels to power air compressor to pump water is.... to be avoided. Better use the solar panel directly connected to an electrical water pump since you can move the solar panel around.

In the end choosing a pneumatic system seems to me you want to choose a less expensive high reliable system by giving up efficiency.

If power is almost free (local wind, "solar" and hydro) - the wind turbine is definitely cheaper without electrical generator - this choice makes sense.

K_Fry, I wasn't scaling things up to commercial proportions. The whole point is that most people cannot. And we all know the economic stuff, if we all believed it, you would not be making boats (because there would be no market) and this forum would never have posts (because there is always someone somewhere making a better product cheaper). However, are you aware that wind turbines ARE available COMMERCIALLY that have a compressor ON the Shaft beside the turbine? Here is a neat link to a 4 psi science project http://www.youtube.com/watch?v=JW6nlS3Dcn8 in a science museum. And here is something about a commercial one http://www.pondreports.com/2008/09/windmill-air-compressor-pumps.html and http://www.koenderswindmills.com And if you read the why, you will find that they are simpler and more reliable than the electrical systems.

Hi gaiatechnician,

K_Fry, I wasn't scaling things up to commercial proportions.

Yes, I knew that. My point was that many people do not perceive losses until they are large. When all these small losses are added together, then people notice. Sometimes the losses are so large that government feels that it needs to step in to promote the common good. Thus, in Europe (for example) there are regulations in place re using high efficiency motors.

In the US, the DOE estimates that the wire-to-work efficiency of air systems in industrial settings is 10%. See this report. If we can substitute 80% (wire-to-work) efficient electric motors and linear actuators for air motors and cylinders then we can reduce our carbon footprint by millions of tons.

Fortunately, industry has a profit motive, so that air systems are being used less and less. I still use an air-powered impact wrench in my shop, but will use a battery-powered version when the air version fails (in part because they are so much more convenient). My 3 hp compressor runs about full time to keep up with the air wrench if I am using it a lot. The 500 watts (about 2/3 hp) consumed by a plug-in version does the same work with a small fraction of the input power. Battery versions are only slightly less efficient that wired versions, but far more convenient.

However, are you aware that wind turbines ARE available COMMERCIALLY that have a compressor ON the Shaft beside the turbine?

Yes, I am. They are substantially less efficient (even measured at the head) than electricity generating turbines. The losses become even greater when the item to be powered is a distance from the head.

K Fry, efficiency does not matter. In the real world, it is price over earnings that counts. And if you can make it at "hobby project" with low price and difficulty, it goes into a whole different economic category.

My point is that nobody is using tiny spot power sources (at all) because it costs too much to generate electricity with them. It is a mindset. You HAVE to generate electricity.

There is NO OTHER WAY. Even if it is 10 watts and variable and in the middle of nowhere, and easily stolen you gotta gotta do electricity and haul in batteries, charge controllers and the works . And even if it is low carbon like small wind or low head hydro. "O well, you cannot use it because it is low efficiency", (so haul in a diesel engine instead). That is the mindset. But the real choice for low head hydro or small wind is either use it in a low tech cheap way or use fossil fuel instead. You are refusing even to look at low pressure pneumatics, 4 psi simply is not the same as compressing to 120 psi. Nobody has done it. Nobody has a clue about whether it is worthwhile or not. Do not look and you will not find, is the sign of the closed mind.

I hope I'm not upsetting you. The all caps segments make it look like you are shouting.

I'm finding your writing a little hard to follow. It is full of extreme statements, some of which are probably meant to be rhetorical, maybe ironic, or perhaps sarcastic.

For example, consider your very first statement in the post to which I am responding now. "K Fry, efficiency does not matter." That is obviously untrue. If cars were twice as efficient as they are now, we'd be consuming half as much petroleum, relying less on foreign sources, and creating half the CO2 as we do now in that segment. Cars are just one segment in which efficiency is critical. Virtually every large corporation invests heavily in improving efficiency.

Perhaps you meant that efficiency does not matter to you?

You write "My point is that nobody is using tiny spot power sources (at all) because it costs too much to generate electricity with them." That is clearly untrue. Thousands of people use solar powered calculators, solar chargers for phones and laptops. Sailboats around the world use windmills, water turbines, and solar cells to generate small amounts of power. Millions ride bicycles, and pump water by hand or by windmills. When you use words like "nobody" and "at all," you are being extreme, seeing things in black and white when there are shades of grey. You provided a link to the wind turbine compressor company -- they are using pretty tiny spot power sources, are they not?

You wrote "You HAVE to generate electricity. There is NO OTHER WAY. Even if it is 10 watts and variable and in the middle of nowhere, and easily stolen you gotta gotta do electricity and haul in batteries, charge controllers and the works." Although you might imagine that someone is saying this to you, I have never been told such things, and I have not read that many others are being told such things. There are still windmills pumping water in places where it makes sense to do so. I move water to my plants by hand. No one has told me that I have to move it electrically, pneumatically with a pedal cranked pump, or with an engine driven pump.

You may imagine that I am "refusing to even look at low pressure pneumatics" but how could you possibly know that? I have both "looked at" and used low pressure pneumatics. I think that in my very first post in the thread I said that such systems can work just fine, if efficiency is not your first concern, or if the system is so small that the energy costs are trivial.

When I water my pepper plant, (which seems quite similar to the one in Chicago pictured above), I fill a watering can, and walk over to the plant. That uses more energy than if I had a small tube running over to the plant from the faucet. I probably burn an extra 5 calories in the process. But I don't mind doing it. And no one has suggested that I should use a diesel-powered pump.

You cannot write "Nobody has a clue about whether it is worthwhile or not" and expect to be taken seriously. I doubt that you have spoken about the subject to everyone in the world, right? I'd hope that at least you feel that using 4 psi pneumatics is worthwhile for your project, and I suspect there are others as well. It seems to me that, for your project, it works ok.

Since this post, I have improved the airlift pump. A windowfarmer in the USA is pumping to 7 ft high "easily" with 14 inches or less of submergence using the improved pump. Also, I found cheap irrigation line 27 dollars for 250 meters of 3/8 tubing and it is ideal for the pneumatic grid system. I currently supply a test water feature (a little waterwheel, and a pond with goldfish, and 8 pallet gardens from a 4.5 Watt bubble pump in a shed. So 9 of the little airlift pumps running at the same time. They run at about 1 psi. Sometimes a little more sometimes less. (I have a manometer in the shed to measure the pressure). It takes about 20 litres of air per hour to run 1 airlift pump on the grid. A couple of people in the Stirling engine community have expressed interest in building solar thermal powered Stirling engines to run such a grid. The pallet garden project is at http://www.youtube.com/playlist?list=PL00C41C26C91A76BB

Brian