TheBackShed.com

Forum Index : Other Stuff : Compressed Air Energy Storage

Page 2 of 2

Author

Message

Oscar4u

Regular Member

Joined: 23/02/2011
Location: New Zealand
Posts: 42

Posted: 10:06am 01 May 2011

Copy link to clipboard

Print this post

Hello Norcold
I wonder if pneumatic is the way to store energy. You need lots of air to generate power. Is it worthwhile to try and generate some electricity running straight of an compressor as an experiment? I suspect your losses would be huge. If I ever store compressed air it would be to save having an compressor motor rather then to store energy. Am interested in where this conversation leads to. Cheers
Oscar

Oscar4u - for all your rotary cowshed repairs

mac46

Guru

Joined: 07/02/2008
Location: United States
Posts: 412

Posted: 11:59am 01 May 2011

Copy link to clipboard

Print this post

At one point in time ...a few computors ago, I had a short story clip and picture of a father and son who were killed when a rear tractor tire ruptured as they were inflateing it, force was so great that it tore their clothing off. This happened many years ago and so any details are foggy in my mind. I would not attempt any storage of compressed air in unapproved containers at any pressure. Please, ask you'rself "what are the risks", when safety rules come into play, and you don't play by the rules.
I'm planning compressed air storage for use in the shop for runniing air tools, and the occasional "low tire". The storage vessel will be a 500 gallon LPGas tank, I salvaged it from the back waters after the flood a few years back.
I've another story...a aircompressor tank ruptured while it was being used by a close relative while painting a automobile. He had shut all windows and doors to the garage to keep out the dust, (did'nt want dust in the new paint), anyway, the sudden air pressure change in the garage blew out the windows. He was unharmed in any way. The cause of the tank failure was internal rust from moisture collecting inside the tank. The compressor had done a back flip and was unside down still running when I rushed inside to find out what happened. What a mess that was.
.....Mac46 (sorry we did'nt tkink to take a picture at the time)

I'm just a farmer

MacGyver

Guru

Joined: 12/05/2009
Location: United States
Posts: 1329

Posted: 07:02pm 01 May 2011

Copy link to clipboard

Print this post

Crew

Being a retired plumbing contractor, I have access to used water heaters. Electrics are the easiest to use and many times folks change them before they leak. I use them to store my compressed air in, but I will say this much: I don't let the pressure get above 60 psig. I have a regulator that has a mechanical "pop-off" plug on it, so if the pressure rises beyond the pre-set, it lets out the extra.

I know what some of you are thinking and that's this, "60 psi? Can't do much work with such a low pressure; I'll pass."

Woah! Let's do a little sandbox hydraulics for a moment here. For those who don't think there's much power in 60 psig air, let me ask you if there's enough to stop your car when it's going 100 kph. It is, in fact, more than is needed. When you mash your brake pedal with mere foot power, a master piston and cylinder delivers low-volume, high-pressure oil to several "slave" units on each of your wheels' braking system. Those pistons are of a larger diameter and shorter stroke, so the work available is HUGE. It's basic hydraulics.

That's what I do with the wind stored in the water heater tanks. It' is pumped into the tank at small, insignificant little squirts and used against a larger-area piston in the "engine" at the other end. You'd be amazed at what can be accomplished with 60 psig air!

If you want to do lots of work, it's true, you'll need a rather large volume, but for most of us, who charge batteries with an alternator coupled to either a windmill or a stationary engine, this task can be done in several sessions. The battery will accept a charge all at once or over the course of a day in several sessions; it doesn't care.

Besides, a windmill running a little pump is lots of fun to watch. Folks passing by seeing it ask, "W-T-well, you know!

. . . . . Mac

Nothing difficult is ever easy!
Perhaps better stated in the words of Morgan Freeman,
"Where there is no struggle, there is no progress!"
Copeville, Texas

yahoo2

Guru

Joined: 05/04/2011
Location: Australia
Posts: 1166

Posted: 08:26am 02 May 2011

Copy link to clipboard

Print this post

I agree with mac46,you need a pressure vessel not a plastic tank. Burying it will just postpone the rupture and make it a bigger boom when it happens.

If you are serious about this it is worth doing some legwork and sniffing out some cheap tanks, the reason I suggested large LP gas Tanks is they are the biggest buyer in the market and sell with the lowest margin, they are identical to an air receiver tank built on the same production line.

I have seen NEW tanks sold for the price of the steel, a qualified fitter can add extra outlets and a mobile pressure testing service will ticket it for 10 years. It will be tested to 500 PSI rated for 350 PSI and setup for 250 PSI. The only downside is they are heavy, you need something big to get them off the truck.

The professionals use air in three stages high pressure tank 250 PSI, low pressure tank 80 PSI, vacuum tank. You transfer air between the tanks to do the work and run your turbine pumps to fill your high pressure tank and evacuate the vacuum tank (between the tanks in a closed system).That way, only a small amount of fresh moist air enters the system , which means your lubricant is not degraded and the air motors don't seize up.

This works great until you buy a plasma cutter or build a chicken gun.

I'm confused, no wait... maybe I'm not...

MacGyver

Guru

Joined: 12/05/2009
Location: United States
Posts: 1329

Posted: 03:23pm 02 May 2011

Copy link to clipboard

Print this post

Crew

I love that yellow submarine; can't top that one!

Someone PMed me and asked what a water heater was. Apparently, some stuff is not as common as one might think and maybe what I call a "water heater" is called something else in other parts of the world. So, to even the playing field, I've included a picture of the 20-gallon electric water heater I use on my land yacht. The place came with a 5-gallon gas-fired heater, but 5 gallons of hot water just doesn't cut it when you're as big as Shrek!

Here's a shot of a Bradford White 20-gallon electric water heater:

Hmmmm . . . for some reason, I'm unable to load a picture. I get a 404 error. That's a first! I'll try again later.

Note to crew: please don't respond to this until I upload that picture or the edit feature will go bye-bye and I'll have to start another message. Thanks.

. . . . . . Mac

Edited by MacGyver 2011-05-04

Nothing difficult is ever easy!
Perhaps better stated in the words of Morgan Freeman,
"Where there is no struggle, there is no progress!"
Copeville, Texas

rossmcn

Newbie

Joined: 03/05/2011
Location: Australia
Posts: 4

Posted: 04:44pm 02 May 2011

Copy link to clipboard

Print this post

Hi
my first time participating
regarding compressed air engines, there is a fellow Angelo DiPietro in Melbourne who makes these amazingly efficient air driven motors
http://www.engineair.com.au/
he is a bit wacky, aren't most inventors, but his technology stacks up and I have been trying to get him to build a reverse engine to use as a compressor output from a VAWT I have designed. I am investigating using large, old boiler tanks for air storage to smooth out the fluctuations in wind output. I am talking 2-5000 litre and 100dpi if I can get it.
They are cheap and easy to weld/seal. They just weigh a lot, a bit difficult to manage. Free, compressed air is quite valuable.
cheers
Ross

Technology has the advantage that it is 'real'. Theories, even laws, are ultimately only our best current model. Consequently, inevitably they will eventually be replaced with a better model

MacGyver

Guru

Joined: 12/05/2009
Location: United States
Posts: 1329

Posted: 08:43pm 02 May 2011

Copy link to clipboard

Print this post

rossmcn

Welcome to the 4m. If you can wait it out, I'll be posting several compressor and engine builds here on the 4m in the "Other Stuff" catagory (here).

As for that picture of the "water heater" from my post just before yours:

Dang! It still doesn't work. GLEN: HELP !

EDIT:

Hmmm . . . . . must be my camera, eh? I yanked this picture off the Internet. My "water heater" looks just like this one, except the inlet and outlet ports are on the side. I got it fitted that way to facilitate a future "solar-assist" loop to a yet-to-be-constructed 1-meter square flat panel on top of my flat-roofed land yacht.

At any rate, THAT'S what I call a "water heater".

. . . . . Mac

Edited by MacGyver 2011-05-04

Nothing difficult is ever easy!
Perhaps better stated in the words of Morgan Freeman,
"Where there is no struggle, there is no progress!"
Copeville, Texas

norcold

Guru

Joined: 06/02/2011
Location: Australia
Posts: 670

Posted: 08:52pm 02 May 2011

Copy link to clipboard

Print this post

Remember way back seeing a photo of a body identation in a workshop roof. Apparently a truckie was inflating a laying down truck tyre, when the bead let go .He was leaning over the tyre when it let go. Batteries or energy storage are the bottleneck that is holding back alternative energy, I am into 4years of a remote solar household system . The cost of replacing the batteries is approximately equal to the cost of power saving, taking that they will have a 10 year life. That does not take into consideration the cost of repairs to Inverter, regulator, panels etc.
On a large scale energy supply companies are trialling used up gas wells, oil wells and worked out mines to store compressed air. Yahoo- Compressed Air Energy Storage and a few hits will show this interest. That yellow submarine may have the answer to storage on a small scale, from my preliminary investigations(very basic) about 5000l would be needed. The higher the pressure the less volume required.
This 4m`s posts are revealing the interest in such, but plastic whether just as a bladder has the advantage of being corrosion proof over steel. Just need an economical and strong way of using to give a long life. Edited by norcold 2011-05-04

We come from the land downunder.
Vic

MacGyver

Guru

Joined: 12/05/2009
Location: United States
Posts: 1329

Posted: 09:29pm 02 May 2011

Copy link to clipboard

Print this post

norcold

Of course, the other side of that coin is "reduce your consumption" and you won't need such a large storage receiver. I know that sounds trite, but it's been practiced forever in business.

By that I mean, would you rather sell a thousand hotdogs at a buck or one giant one for $1,000? The big one looks inviting until you realize you'll have to have a bun as large as a truck, not to mention the gallons of mustard and mayonaise; and what if nobody buys it? You'll be stuck with a rotting thousand-pound weenie!

Anyway, all the stuff I build is small, but I've noticed that I can get a lot done with a small tool (as it were).

Hide and watch; I'll be posting several "little" projects that'll astound you as far as how much "work" they'll each do.

. . . . . Mac

Nothing difficult is ever easy!
Perhaps better stated in the words of Morgan Freeman,
"Where there is no struggle, there is no progress!"
Copeville, Texas

norcold

Guru

Joined: 06/02/2011
Location: Australia
Posts: 670

Posted: 11:57pm 02 May 2011

Copy link to clipboard

Print this post

Mac

Spot on reduce consumption. We average out in our system 5.2kW/hr each day. I think the average households consumption exceeds 25kW/hr each day. Just hate to see the excess power our system produces go to waste instead of being able to utilize it on a rainy day. We use a backup diesel generator for such days. But as we live in sunny NQ our system on most days is floating the battery charge by 1pm. Just those rainy days during the wet. Beside all that batteries, as we know, whilst they may be the best storage option we have are not the ultimate. Better energy storage solutions are the key to more wide use of AE. As I see it I require a energy store of approx 2days consumption as back-up. At present I`m getting up 2 of PhilM`s Mills(1 up and producing), thus feel my energy production will probably double or better my consumption. Like you I like to tinker and really appreciate the input you and all others have offered to the Compressed Air Storage Post, the thread has me leaning at present more towards using water although the "yellow submarine" shows a lot of potential. I`m currently searching for such locally but would do as you have and look into the air generator before extending in one direction. My posts should indicate I am very raw but thats how I started out in AE back in the early 80`s. My Toyota troop carrier I had jokingly refered to as running on solar, had panels to power camping refrig etc. It worked than and still does now but believe I received a lot of strange looks, solar just wasn`t viewed as being anything but a toy back than.

We come from the land downunder.
Vic

VK4AYQ
Guru

Joined: 02/12/2009
Location: Australia
Posts: 2539

Posted: 02:54am 03 May 2011

Copy link to clipboard

Print this post

Hi Norcold

Many years ago I tried to do a compressed air system storage system but found it very inefficient as in testing it took a 5HP air compressor to run a 1.5 HP air motor, the motor was the most efficient I could get at the time, it was a 5 piston swash plate motor with positive timed valving through a rotary valve.

The only one that did any better was a converted steam engine with expansion governing, but it was still less than 50% return on power.

For workshop use with air tools air was useful but for power generation it was hopeless.

All the best

Bob

Foolin Around

MacGyver

Guru

Joined: 12/05/2009
Location: United States
Posts: 1329

Posted: 03:11pm 03 May 2011

Copy link to clipboard

Print this post

Crew

I got a PM and was asked if the water heaters here (USA) were "copper lined". I thought I'd share my answer, as there are likely others wondering the same thing:

'50 years ago they were. Today, the only thing copper lined in the USA is our money! No, they're all-steel, welded tanks with rounded ends, so the internal pressure doesn't pop the thing.'

. . . . . Mac

Nothing difficult is ever easy!
Perhaps better stated in the words of Morgan Freeman,
"Where there is no struggle, there is no progress!"
Copeville, Texas

MacGyver

Guru

Joined: 12/05/2009
Location: United States
Posts: 1329

Posted: 02:51am 04 May 2011

Copy link to clipboard

Print this post

This Is Just A Test

I was having problems uploading pictures and Gizmo thought it might have been something he did to the 4m to prevent spamming. In that light, I'll try to upload a picture of the proverbial can of Spam here:

Mmmmmmmmm . . . Yummy! Looks like it's fixed.

Thanks, Glen.

. . . . . Mac

Nothing difficult is ever easy!
Perhaps better stated in the words of Morgan Freeman,
"Where there is no struggle, there is no progress!"
Copeville, Texas

Page 2 of 2

Print this page

To reply to this topic, you need to log in.