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Talk:Directory:Davidson Hill Venturi by Tidal Energy Pty Ltd

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Discussion page for Directory:Davidson Hill Venturi by Tidal Energy Pty Ltd.

Image:Davidson Hill turbine and housing 95x95.jpg

Patented venturi containment system increases turbine efficiency 3.85 times what the turbine would produce without the system, making this a world leading design. The company is now commencing the commercialization stage, with an expected price that competes with coal in the range of 3.5 to 6 cents per kw-h.

Comments

A Reliable, Green and Blue Technology

On Jan. 22, 2008, New Energy Congress member, Congress:Member:Leslie R. Pastor wrote:

I vote Top 10 for this technology.

I love the technology. It is definitely 'green' and 'blue.' The rotation of the Earth, the tides, and the interaction with the Moon make it a definite long range technology.

It is as simple as you can get. And it conforms to all the known laws of physics.

Why Not T100

On Jan. 23, 2008, New Energy Congress member, Congress:Member:Robert A. Nelson of http://RexResearch.com wrote:

(answering the question: "Why didn't you vote for this technology to be in the Congress:Top 100 Technologies -- RD?)

(Comments by Aaron Davidson interspersed, indented.)

1. Government/environmental controls would stop much of the obvious applications, especially by individuals. Independence is not allowable.

: Not so see comments below. Sorry to hear your opinion is wrong. -- TidalEnergy 02:06, 30 Jan 2008 (EST)

2. Rivers are drying up, and will continue to do so (Rev. -- the waters of the earth shall dry up..)

: Again this is answered below. Did you take a minute to read the comments posted in response? -- TidalEnergy 02:06, 30 Jan 2008 (EST)

3. Ocean applications would require redesign of existing systems, testing &c, which would delay implementation. And very few ocean-power designs exist or are being developed to which the tech could be applied...

: Not so again. The ocean energy industry has developed in leaps and bounds - but not in the US. As stated below there are in the EU who cater specifically for this technology and its peers. -- TidalEnergy 02:06, 30 Jan 2008 (EST)

4. The Top 100 list doesnt include proven free energy systems that could be developed/redeveloped quickly even though they don't meet the List criteria for market plans &c. -- e.g., Gritskevich, Hubbard, Hendershot, Coler (especially), Grey, Moray, &c &c... The T-100 List doesnt meet my criteria...

: I am sorry to say that you are wrong. The Top 100 does include technologies currently under development.See comments below. -- TidalEnergy 02:06, 30 Jan 2008 (EST)

: Though I would like to have your vote I would rather it be on just terms with your full understanding of the technology and the industry. Sadly you have missed the point/s. At the risk of offending your ego I would have the turth known and let the chips fall where they may. Might I suggest you read and fully aquaint yourself with all the facts as it does your credibility no good when you don't. No offence! -- TidalEnergy 02:06, 30 Jan 2008 (EST)

: Sad to hear that you believe it does not fit the Top 100 but glad to hear your opinion. Governments especially in the EU (along with investors) are pushing this and others with big incentives. Designs have been trialed here for a number of years successfully so little further R&D is required on deployment. If you doubt what I say see what technology and applications the wind boys use to put wind turbines in the ocean. Lateral engineering practice applications have been around for some time. This technology has now reached its time - all the ducks are lined up. Also keep in mind that the rivers in the EU (Britian especially) are running at 125% to 150% capacity as global warming alters their rain fall patterns. Built environment engineers in the UK are now looking for ways to stabalise river banks and protect the built environment from erosion caused by rivers running faster then they have in the past. The DHVTurbine has been suggested as a means to remove some of the destructive energy from the flow at points where erosion is greatest. There is then a net benefit of free energy. Globally there is a need for clean energy and cheap hydrogen for transport - this ticks all the boxes. Thanks again for your input. Iron sharpens iron as they say. -- TidalEnergy 20:55, 23 Jan 2008 (EST)

::Looking at the list of "Top 100", Blue Energy is at number 29 and the DHV Turbine is streets ahead of them in both performance AND development! Blue Energy has self acclaimed much since the late 1900's - incuding a Patent - but so far no Patent and no commercialisation. Verdant at Number 33 can not compete with the performance of the DHV Turbine. Verdant are ahead in terms of commercialisation. Good on em, I say! These are just two without touching on wind technologies. To my mind it seems hard to justify why these have made the list and not the DHV Turbine which holds the greatest potential for providing clean green renewable energy to an energy hungry globe. Perhaps because these were early birds they are still on the list? Maybe it's time to re-evaluate the Top 100 and have a real purge? -- TidalEnergy 23:58, 23 Jan 2008 (EST)

[...]

7. It should be applied to wind generators first because that tech is well-developed w/ an established market, w/ small units applicable to independent homesteader. Screw the city slaves. They'll take whatever they can get they dont care. If they did, they'd do something about it. Since they dont, they can suffer in ignorance. Better, they can learn to do without, 'cause that's what it's going to come to long before the D-H Venturi system gets implemented. But I do think it's a fine invention...

Changed my vote again

On Jan. 29, 2008, New Energy Congress member, Congress:Member:Sepp Hasslberger writes:

(Comments by Aaron Davidson interspersed, indented.)

I had first voted "not top 100", then changed to "top 100" but now have again changed to "not enough data". The reason for this is that there does not seem to be any hardware that is anywhere near deployment.

1. The actual turbine configuration and generator, it seems, has not been decided on. The article says "D&H plan to keep cost down by the use off-the-shelf generators, readily available in the industry, which are robust in ocean environments such as are used in the submarine industry." I am unaware of any "off the shelf" underwater turbines and generators. In fact, one of the greatest trouble with marine energy production is that material degradation in the salt water environment has not been solved, at least not to the extent where one could just buy a turbine and generator "off the shelf".

: Sepp, the farmer said - "there aint no such animal as a giraffe" - when it was described to him because he had never seen one before. -- TidalEnergy 06:38, 30 Jan 2008 (EST)

: Just so everyone knows here is my giraffe - http://www.haywardtyler.com/

: I hope theses folks don't mind me giving em a plug here as they make excellent specialist built generators for the marine energy industry. There are to many companies to list here that make off the shelf gear boxes. -- TidalEnergy 06:38, 30 Jan 2008 (EST)

2. The "projects" part of the official website is empty. There does not seem to have been any substantial testing of the necessary hardware, at least judging from the available data on the company's site. No prototype generator has been installed anywhere, much less gone through the rigors of actual use, yet the article states that "the company is now commencing the commercialization stage". We should ask how they are going to commercialize if the configuration has not been fully decided on, much less tested.

: There has been testing up to the commercial prototype. The web site was down graded soewmtime back to stop copy cats. It may not fit your ideas of how things should be done - but this is the way we decided to do it. Whether our strategy is right or wrong does not necessarily mean it has not been done. My advice is to look at the photos. A 40 foot boat to carry a tubine being tested is a dead give away. -- TidalEnergy 06:38, 30 Jan 2008 (EST)

3. The idea of increasing velocity of water flow by providing a narrowing path is great. I have proposed to use this in a river-flow hydroelectric setting in Dynamic Hydropower. However as it currently stands, I do not see the Davidson Hill Venturi as a ready technology as yet. It just isn't ready to deploy from what I can see, and it isn't even close.

:It is currently under commercialisation in North America, the EU (two countries), India and Australia in 2008. You should read about it in the media soon. More then what I would expect from some technologies on the Top 100 list. I said it before and say it here agian - the Top 100 needs serious review. -- TidalEnergy 06:38, 30 Jan 2008 (EST)

Betz Rules!?

The Betz Rule that fixes the upper limit of 60% (59.27%) of energy an open or free steam turbine does NOT apply to shrouded turbines such as the Davidson-Hill Venturi Turbine. It only applies to turbines without the venturi or shroud. This fact has caused much consternation to some who struggle with the fact that a shrouded turbine is able to exceed the Betz limit. -- Tidal energy 23:17, 22 Jan 2008 (EST)

Efficiencies of water current turbines

IT is understood by this editor that the maximum efficiency achieved by water current turbine in free stream is in the order of 20%-25%. This much lower then could be expected of a similar wind turbine in free stream in air of about 40%-60%.

Why is this so?

While this remains the subject of further examination and a possible PhD thesis it is believed to be as a result of the 832 time higher density of water compared to air.

A cubic meter of air weighs about 1.25 kg at sea level while a cubic meter of sea water weighs around 1025 kg.

An over simplified way of explaining what is happening is to compare an object spinning in air. You can spin a turbine or propellor in air and it will keep spinning until friction slows it to a stop (unless another force causes it to keep spinning). Howeverwhen you try to do the same under water the propellor immedeiately comes to a halt due to the heavier medium of the water.

-- Tidal Energy 23:16, 22 Jan 2008 (EST)

The

The Viktor Schauberger system was high on the list of Tidal Energy Pty Ltd priorities when Davidson and Hill (D&H) first began feasibility testing in the late 1990's.

Unfortunately for Viktor D&H found that placing the turbine in the constriction produced a blockage causing flow upstream to slow and build up. In effect the turbine while producing some small increase in power acted more like a dam reducing flow over the turbine. The flow had "no where to go" when a load was placed on the turbine so began to backup upstream of the turbine. Any vortex that was or should have been created was lost.

D&H conclude that the system would only work in free stream where the vortex was allowed to form down stream of the turbine thereby allowing more flow to be drawn in at the "up" stream inlet. -- TidalEnergy 17:21, 30 Jan 2008 (EST)

Aaron has made his point

In interspersing his comments with my previous ones, Aaron has made his point. He has requested that I change my views and state so publicly here on this discussion page, and I have actually done so some time ago, but did not save my edits. So here I try to re-construct what I said.

:Seems a little strange that someone who lectures on wiki is not able to upload an edit.Tidal energy 19:46, 13 Mar 2008 (EDT)

I have re-examined the question and agree that Aaron's tech should be on the "top 100" list. Indeed I have changed my vote to reflect that new understanding.

:It is an enigma to us that both Blue Energy and Verdant are in the top 20-30. Yet a more advanced AND Patented technolgy is not.Tidal energy 19:27, 13 Mar 2008 (EDT)

I do not agree with Aaron that Schauberger has made a mistake. Rather I believe that the Davidson Hill Venturi is based on an entirely different principle as that proposed by Schauberger. A venturi, as I understand it, is a constriction in a pipe, which forces a flow to accelerate, as the low pressure after the constriction creates a suction. That acceleration is used in the Davidson Hill Venturi to good effect, accelerating the flow of an underwater current so more energy will be available to the turbine that is combined with the venturi.

:D&H studied Schauberger and found that not only was his math wrong but it was not possible to create an upstream vortex using his apparatus. Sepp's lack of math skills and basic understanding of the laws of physics seems to be evident. Had Sepp taken the time to read the peer review by Kirke on the main page he would have all the answers or "DATA" that he required and not brought his credibility into question.Tidal energy 19:27, 13 Mar 2008 (EDT)

Schauberger's idea instead involves a vortex, which is a self-accelerating and self-constricting corkscrew-type flow. This is explained in Schauberger's patent on the Suction Turbine, which forms the basis of my article Dynamic Hydropower

I would like to point out that some of the comments I made above are still valid, as indeed confirmed by Aaron's interspersed comments.

:Sepp could not be further from the truth about valid points. When tested by D&H in the late 1990's the Schauberger apparatus created turbulence detuning the power output. The basis of all science - to reproduce the same results from the same apparatus by different people - meant that Schauberger work was thrown out by D&H.Tidal energy 19:27, 13 Mar 2008 (EDT)

On point 2, Aaron says that "The web site was down graded sometime back to stop copy cats." This rather confirms what I said about the projects part of the official website being empty and the lack of (publicly available) data on the testing done. I have taken the advice and looked at the photos again, but they do not tell me the story of what testing was done and more importantly, what the outcome of the tests was. The official website, to say the least, is not very forthcoming in this regard.

:Should Sepp invent and Patent his own work some day he will find that in the real world there exists "COMMERCIAL IN CONFIDENCE and NON-DISCLOSURE" to protect the interests of the respective parties.

:Using this to say it is not so, There was an error working with the wiki: Code[1] by Sepp - according to Sepp there are "no off the shelf generators" yet a simple search will uncover an abundance of tidal generators. Had Sepp known what a peer review is or had he taken time to read the data by Kirke he may have saved his credibility.Tidal energy 19:27, 13 Mar 2008 (EDT)

On point 3, Aaron scolds me for saying the technology "just isn't ready to deploy from what I can see", saying the technology is "currently under commercialisation in North America, the EU (two countries), India and Australia in 2008" but then he adds: "You should read about it in the media soon". If Aaron cannot tell us any details about these projects, but refers us to future articles in the media, I don't see how he can reasonably request acknowledgement that the technology is ready for commercialization. Let's see the data.

:The real world is somewhat different from that of the lay person as stated above.Tidal energy 19:28, 13 Mar 2008 (EDT)

One more thing: I would like to remind everyone that this is the "talk page" of a Wiki article, which means it is the place editors talk among themselves about the reasons for particular edits or make comments about the subject of the article. This is NOT the article in the Wiki, which a reader would normally go to and read about the technology being described. --Vortexpower 20:14, 11 Mar 2008 (EDT)

:Sepp patronises by pointing out how wiki works but is unable to upload discussion. Hmmmm.Tidal energy 19:28, 13 Mar 2008 (EDT)

:In summary the data was on the main page from day one for Sepp to read all along but he failed to do so. His lack of formal understanding of the basic physics is evidenced by the formula below. Schauberger has an interesting idea that fails to live up to his claims. While Sepp would like to influence people with his claims of a background in physics he has failed to do so and damaged his credibility in the process. Sorry!Tidal energy 19:36, 13 Mar 2008 (EDT)

:If this site is to be relevent and backed by hard science it needs to be more rigid in what is placed here and by who. Allowing people unskilled in the art to pass judgement is damaging and dangerous, as the wrong comment at the wrong time, in the wrong place, by the wrong person, can be taken the wrong way and have dire consequences. Perhaps each comment should be qualified - i.e. I have 10 years of expericence in the field, have a engineering degree, or I have an interest only and hold no formal qualifications - could be the order of the day. At least we would know whose opinions are worth reading and believing.Tidal energy 19:36, 13 Mar 2008 (EDT)

:The energy calculations below are taken from Kirke on the main page and are the industry standard for energy produced by a free stream turbine. They contain NO HEAD values as does Schauberger's math. Sad to say had Schauberger been alive today he would have benefited from more research and may have revised his sums.Tidal energy 19:41, 13 Mar 2008 (EDT)

:The sad fact remains that to the unskilled the math is complicated and difficult to understand. For the record the formulas have been included below.Tidal energy 19:41, 13 Mar 2008 (EDT)

The

The Viktor Schauberger system was high on the list of Tidal Energy Pty Ltd priorities when Davidson and Hill (D&H) first began feasibility testing in the late 1990's.

Unfortunately for Viktor D&H found that placing the turbine in the constriction produced a blockage causing flow upstream to slow and build up. In effect the turbine while producing some small increase in power acted more like a dam reducing flow over the turbine. The flow had "no where to go" when a load was placed on the turbine so began to backup upstream of the turbine. Any vortex that was or should have been created was lost.

D&H conclude that the system would only work in free stream where the vortex was allowed to form down stream of the turbine thereby allowing more flow to be drawn in at the "up" stream inlet.TidalEnergy 17:23, 30 Jan 2008 (EST)

Viktor Schauberger wrong formula?

Looking closer at the article on Viktor Schauberger's formulas I have come to the conclusion that they may be wrong. The correct formula for energy in moving water is

Power (in Watts) = 0.5xrhoxAxv3

A turbine efficiency is then added to the equation,

Power (in Watts) a turbine can extract = 0.5xrhoxAxv3 x Ctp.

There is no pressure or head factor in the equation.

I would say that all his numbers on the energy available in flow are therefore wrong.TidalEnergy 22:09, 5 Feb 2008 (EST)

Retrieved from "http://peswiki.com/index.php/Talk:Congress:Member:Sepp_Hasslberger"

:The formulas above were posted on Sepp's main page. As of the writing of this no response has been added to this by Sepp. There may be other reasons but two could be that Sepp is unskilled in the physics maths or agrees the sums are correct and need warrant no response.Tidal energy 19:45, 13 Mar 2008 (EDT)

Comments