Comments on: The Di Pietro Compressed Air Motor – Alternative Clean Energy, Today

By: 29er

29er — Wed, 01 Jun 2011 04:08:15 +0000

The main reason for the negative comments about this technology seem to be centred around where the energy comes in the first instance. By using a wind turbine to drive a compressor directly you avoid the losses of converting to electricity and then to motive power and gain the advantage of storing the energy for when you need it rather than limiting it to when it can be generated.

By: Shannon DeWolfe

Shannon DeWolfe — Sat, 12 Mar 2011 13:22:33 +0000

I have read with great interest all the comments above. I am saddened to the core to find thinking people with a goal of sustainable energy production read past or belittle the idea of the trompe as a source of compressed air for this motor. Please take a moment to look at this information page about Hoover Dam:

http://www.usbr.gov/lc/hooverdam/faqs/tunlfaqs.html

Near the bottom of the page is a photograph of the discharge gates. Impressive show of power, isn’t it? Let me direct your attention to the last Q&A:

“What is the maximum discharge capacity of the spillways, jet flow gates and powerplant?

“About 500,000 cubic feet per second (cfs). Each spillway can discharge 200,000 cfs. If the spillways were operated at full capacity, the energy of the falling water would be about 25,000,000 horsepower. The flow over each spillway would be about the same as the flow over Niagara Falls, and the drop from the top of the raised spillway gates to the river level would be approximately three times as great.”

25 million horsepower being dumped into the river AFTER capturing up to 10 billion KWH per year of electricity. Even if the Hoover facility routinely dumps only 10% of that volume, that is still a continuous 2.5 million HP untapped going down river.

The air entrainment compressor at Ragged Chutes Mine, linked in the comment by Jon Gemmell, was designed and built by Mr. Charles H. Traylor. That compressor produced 117 PSI in virtually limitless volume piped through 21 miles of large diameter pipe and several more miles of smaller pipe to supply the mines. The Ragged Chutes compressor was rated at 81% efficiency and 5500 HP. Got that? Roughly .002% of the energy released at full flow of the Hoover Dam.

An hydraulic compressor runs with minimal maintenance for decades. Mr. Traylor’s first commercial installation was at Dominion Cotton Mills at Magog, Quebec. That compressor ran continuously for eighty years with only two shutdowns for maintenance. It was roughly 60% efficient and produced 550 HP at 51 PSI. It was retired in 1974 when the mill upgraded their equipment, rendering the compressor superfluous to their needs.

One of Mr. Traylor’s compressors is in use today to power the gates of the Peterborough Lift Lock on the Trent Canal in Ontario. It has run maintenance free for over 100 years.

The air entrainment compressor is not a perfect technology. It is expensive to build. There are environmental concerns to be addressed. It would take a lot of capital and an energy intensive effort to bring a large compressor on line. And, the air must be distributed. However, it is a mature and well understood technology that can be retrofitted to hydroelectric plants or planned as part of new construction. Once running the compressor will run for decades with zero fuel consumption. With a planned rebuilding program it could run for centuries.

Rotary engines powered by air compressed by water; what is the down side?

Refs:

Story of Charles H. Taylor.
http://charleshtaylor.blogspot.com/

Wikipedia entry for the Peterborough Lift.
http://en.wikipedia.org/wiki/Peterborough_Lift_Lock

Google Books result for Taylor’s compressor.
http://books.google.com/books?id=5KeICcAJcH4C&dq=taylor%20compressor%20mills&pg=PA599#v=onepage&q&f=false

Description of the technology as used in German mines during the early part of the 20th century.
http://books.google.com/books?id=tqUJAAAAIAAJ&dq=hydraulic%20air%20compressor&pg=PA219#v=onepage&q&f=false

A book preview of a more recent publication:
http://books.google.com/books?id=VC-RuN6moREC&lpg=SA9-PA32&dq=air%20entrainment%20compressor%20connecticut&pg=SA9-PA32#v=onepage&q&f=false

Useful Google search phrases:

frizell air entrainment compressor

Taylor patent numbers 543,410; 543,411; 543,412, July 23, 1895 — 892772, July 7, 1908

Experiments on the Compression of Air by Direct Action of Water, by J. P. Frizell, 1880

air entrainment compressor norwich connecticut

At Google patents or freepatentsonline, search for these men:

J. P. Frizell
Jens Orten Boving
Paul H. Morton

By: Dan

Dan — Mon, 26 Jul 2010 16:01:09 +0000

I wonder if the compressed air could be used to power a Sterling engine. If the air from the tank is so cold it could cool the cold end of the engine and fuel could be burnt to heat the hot end, creating a big temperature differential. It could be quieter than other compressed air engines.

By: Thomas Fischbacher

Thomas Fischbacher — Mon, 28 Jun 2010 16:09:12 +0000

Cyrus,

I think I happen to know a little bit about classical thermodynamics, and considering what I have seen so far concerning discussions around the concept of “emergy”, I’ve come to the conclusion that pretty much all of what I have seen so far seems to be pseudo-scientific nonsense.

If anyone can come up with methods that give “emergy” efficiencies which are (1) independently verifiable in the sense that different physics-wise competent people tackling the same problem will arrive at comparable numbers, (2) based on an internally self-consistent method, and (3) allow some sort of experimental validation at least for some simple problems, I would much like to hear about that.

In particular, I would like to challenge the “Maximum Em-Power Principle”, which seems to be worshipped by some in pseudo-religious ways, yet not backed by experimental evidence.

Now, this discussion may not directly be related to the topic of this post – but I sense an urgent need to take a deeper look at the “Emergy” concept, in particular as some “Permaculture Celebrities” like David Holmgren advodate it so strongly. If this should turn out to be a red herring (as it seems to me), we better should re-adjust our perspectives and evaluation models rather sooner than later.

By: supachupa

supachupa — Thu, 24 Jun 2010 07:59:34 +0000

Firstly the business model was not mentioned. Compressed air cars are not sold, but instead you have to lease them, which is pretty weak. I imagine they will probably destroy instead of sell off the older models so you are ever enslaved to spending money.

Next, as others said, the physics does not make sense in terms of efficiency.

Thirdly, Sure Bill likes to sell the Trombe/Trompe. Do some research and see how many actually exist and what is required to have a practical one. Why doesn’t the PRI have one if they’re so great? It’s not a realistic way to create and store energy for the masses, and I challenge you to get one going. That technology dates back to before Roman times and I dare say we have learned a few things since then.

Okay, that all said, if this sort of thing was available for small trips, you used an electric pump powered by solar, and you didn’t have to lease it, it would be great for short distances. What percentage of the world’s population does that really help?

And one other thing to consider, compressed air, fuel cells, etc. are ways of STORING energy. The energy has to be sourced from somewhere else, so if we use electric pumps that are fed from coal/nuclear/(or debatable) wind turbines, we are just transferring the problem elsewhere.

So, it’s a solution that could be beneficial to a small percentage of the population. In terms of toting it as the way forward? FAIL.

By: Tim Barker

Tim Barker — Thu, 24 Jun 2010 03:53:13 +0000

I believs compressed air has a future but we have been looking at it with too narrow a focus. Industry uses compressed air because it has some very good qualities, being so innefficient if there were easier cheaper more eficient ways then tey would and do use them. For a start compressed air motors are light simple and easy to make (comparativly)as are compressors. they are also relativly safe as say opposed to electrical devices ,compressed air also doesnt lose energy in transmission (ie as long asyou have a decent resivour at the end then you can send it hundreds even thousands of k’s with no energy lost(of course you have all that extra pipe to fill). A lot of the misconception comes from where compressed air gets its energy from. The suprising answer is its solar energy. Let me explain When we compress air it heats up thermodynamics tells us this is a result of work being done on it and that the heat caused by work done is exactly equivalent.But we also have heat in the air first from, as you guessed solar warming of the atmosphere. Now i didnt study physics at school so im going to generalise but ,say you have air at 25c and you reduce its volume by half ,the air at half volume is at 50c . This air gets shoved in our storage tank and cools to atmospheric temperature. Some time later you come along and use an air tool or motor to do work.The air tool gets cold depending on how efficient it is (and i suspect that the di Petro motor would get very cold due to its high expansion ratio) This is because the the expanding air which is at atmospheric temperature but higher pressure is absorbing energy as heat from the atmosphere as it expands, remember the reverse of the compression process will see this air halve in temp for every doubling in volume. The cold tool is the axpanding air absorbing heat energy out of the environment aroung it. This is why after heating of the compressed air is recognised as giving more bang for your buck. so in essence air at room temp and the air in a compressor tank have exactly the same energy content , it is only the kinetic energy of the compressed air that allows it to expand down to atmospheric pressure absorbing heat energy from the atmosphere and so powering the tool/ motor. As an aside many air tools are designed only to use the kinetic energy of the air to provide power, a true air motor allows the air to expand as much as possible and absorb as much atmospheric heat as possible hence the earlier comment about Angelo’s motor probably feeling very cold. Now there are ways to make compressed air very much more economic and as said earlier compressed air has some unique properties that can be had with very simple methods for example compressed air expanding through a Ranque/Hilsch vortex tube (basically some pipe and washers ) can provide cooling(down to well below freezing) and heating (hot enough to burn you)out of opposite ends . Or compressed air lift water pumps with no moving parts again made out of nothing more than pipes, dont forget those car jacks tipper hoists made out of air bags that you just fill to lift some surprising weights. weve just got to get the compression costs down and there are many ways to do that its just that nobody has yet put them all together in a system.
Cheers Tim

By: Jon Gemmell

Jon Gemmell — Thu, 24 Jun 2010 03:27:40 +0000

Trompes
It is interesting reading the debate about compressed air and how to do this. I was lucky enough to listen to Bill Mollison talk about Trompes and how to compress air by using falling water.
A trompe is ancient technology that was used by the Catalonians and the Romans thousands of years ago to supply a supply of pressurised air for their furnaces. A trompe works by allowing water to fall over a vertical distance. If water is falling the speed it falls more or less is as free fall but slightly is arrested by the pipe that it is falling in. The bubbles of air are carried down much faster than they can rise because they are lighter than the water. As water falls the air bubbles in the water are compressed – the bubbles get smaller and smaller and eventually become a misty blueish dispersion in the water. The compression of air normally generates a significant amount of heat similar to pumping up a bike tyre – however in this process the heat of the compression escapes into the water so that the air is always a little cooler than the water. It is called isothermic air. When the air is released it is very cold so if it is released into a room – you have cold storage or into a box you have a refrigerator. The greatest advantage of compressing air using a trompe is that the air is not heated up by its compression and is therefore very cold, it is dust and contaminate free – it is ultra clean air. Chicago and Paris used trompes to power cars and industry in the early 1900s. One trompe built by miners generated 4600 hp and ran a lot of Paris’ buses, cars and workshops.
This is a clean, sustainable energy source that could be adopted world wide. Check out the info on Trompes used at Ragged Chutes Minehttp://www.cobalt.ca/index.php/ragged-chutes or http://en.wikipedia.org/wiki/Trompe

By: Patrick Blampied

Patrick Blampied — Wed, 23 Jun 2010 15:02:12 +0000

Hi Marcin & everyone else,

The debate has been interesting so far hasn’t it!

I don’t know the kWh to fill the tank. Unfortunately the information presented in the video is as much as can be shared at this point.

I can’t speak on Angelo’s behalf nor do I pretend to fully understand his technology but he seems to have overcome many of the challenges everyone is talking about here and eluded to that in the video.

He even hopped on the post and commented that everyone watch it again carefully!
Angelo: “It looks to me that it was very early in the morning when you Stephan viewed Engineair video.I don’t think you understood what I was saying, however some of your comments are valid, yet you are in the dark for a solution.I recommend that you watch the video again.”

Having talked to the guy in person at length, touring the factory, holding the motor and driving the vehicles, he’s on another level regarding comprehension of energy, and I believe he has something different to the other compressed air technologies – as he said in the above comment “you (all of us – myself included) are in the dark for a solution” but I don’t think he is… He’d have to be on to something to dedicate the last 10 years to developing the motor and no doubt he’s considered every point that has been raised here long ago.

I’ll admit I struggled with whether or not to run with the car angle when interviewing him fully knowing it runs the risk of creating a false sense of security for those not yet wanting to deal with the reality of running on real time energy but at the same time cars seem to capture the imagination. People have a connection with them that they don’t seem to have with anything else. Even I suffer denial and despite revising my expectations, life goals, job, living arrangement and viewing the world through the permaculture lens, I am ironically restoring a 70’s cruiser as the only release from thinking, worrying, dreaming peak oil/climate change every single day and night since ‘I got it’ nearly three years ago now. Don’t ask me why I still do this, I don’t understand it, it’s so stupid but I love it.

Especially in light of the gulf spill the masses seem to listen more and understand the need for change when you talk to them about their car and in turn I’d hoped that those who don’t see the whole picture just yet would watch the video and explore the site a bit more but for those here on the site that do get it I can only say forget about the car aspect while watching and you’ll notice Angelo keeps leading the conversation back to the motor itself, the way it uses energy differently and it’s broader applications.

Anyway I’m sure the debate will continue… but I hope this explains a little further.

By: Marcin Gerwin

Marcin Gerwin — Wed, 23 Jun 2010 10:58:22 +0000

Patrick, do you know much electric energy (in kWh) does it take to compress air to fill a tank in the small car presented in the video? That would help to clear many issues

By: Craig Mackintosh

Craig Mackintosh — Wed, 23 Jun 2010 07:12:03 +0000

Hi Nick, I don’t have a way to search for posts with highest comments. Here’s a couple off the top of my head to give you an idea though:

http://permaculture.org.au/2010/03/12/climate-debate-opinion-vs-evidence/ (62)

http://permaculture.org.au/2010/05/20/the-century-of-self/ (33)