Will this buoyancy engine-based generator work?

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Offline Mootle

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« Reply #100 on: 29/10/2011 10:44:12 »
"I thought we had got to the bottom of the 'laws of physics' - are you still questioning my claims?"
There are two ways your idea could be made to work.
Make it vastly cheaper or get much more energy from it.
I was covering both bases.

OK, we have established that the laws of thermodynamics haven't been violated.

I agree with your summation. The initial line of development will be put the pontoon to work by combining, wind, solar & hydro to greatly increase the energy mix and yield. Zero fossil fuel, Hydrogen and fresh water production is also an option. Either way the engineering would be geared to give a desirable RoI before being presented to prospective investors.

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Offline Mootle

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« Reply #101 on: 29/10/2011 11:13:31 »
EDIT2: I wonder how this stacks up against wind power? I do know that the economics of wind power are (to put it politely) a wee bit dodgy, and the aesthetic impact of wind power can be really horrible. The last time I was in Scotland, I was pretty disgusted by the desecration I observed. 

I don't think you would get a meaningful patent for your idea as it touches on other ideas which are already out there and even if it didn't you would have scuppered it by posting it on an public forum. As per the PM I sent to you, I think it would be a really useful service to offer a private forum where inventors could seek guidance / help with patenting / modelling and presentation from forum members. This would involve nondisclosure contracts being agreed between inventors and contributors. Once priority was in place the idea could then be discussed in an open forum to help refine the idea.

It's not a good idea to publically post any idea without first securing priority with a patent application.

Wind power is a multibillion pound industry. One of the reasons for this is that current legislation guarantees that investors get a good RoI over time. Large, offshore wind projects generate a lot of energy over time and will form an integral part of any renewable energy mix for a island such as the UK.

Hydropower tends to be used as a top up for peak periods of demand owing to the storage element. As the energy mix moves toward renewables the renewable mix reliability will become more important.

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Offline Bored chemist

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« Reply #102 on: 29/10/2011 13:25:14 »
"In summary and disregarding areas of speculation the response was that the principle is sound and that the claimed energy balance and."
I don't agree that the " potential revenue stream is theoretically possible".
The revenue is small.
Whatever you make the structure from it will need to be maintained and repaired.
I think that the ongoing costs will exceed the revenue.
The only way it could conceivably work would be if we voted in a government who really wanted to waste money backing this scheme in spite of the fact that it will never produce as good a rate of return (KWH/£) as, for example, a wind turbine.
To get this to work you need to go into politics in a big way.
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Offline Bored chemist

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« Reply #103 on: 29/10/2011 16:04:51 »
"You seem to be confusing revenue with cost."
No, since I said "costs will exceed the revenue" there's no way I could have thought they were the same thing.

The difference is clear to me. One is money coming in and the other is money going out.
To be a success, the money coming in has to exceed the money going out.
I don't think your system will or can ever achieve that.
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Offline Mootle

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« Reply #104 on: 29/10/2011 16:50:32 »
I don't agree that the " potential revenue stream is theoretically possible".

You say that but from your previous post the above quote is flawed. Once the energy generation potential is agreed, the stated revenue is also deemed to be agreed since the revenue is calculated directly from the energy that is generated.

As to the cost, at this point in time I would agree that your 'guess' is as good as mine. However, when writing business cases I prefer to work it out. If the answer turns out per your speculation I will be the first to admit that the idea doesn't hold water but for now I simply do not have an answer to that question as the design development has not taken place.

ps. I deleted my earlier post as I modified that by mistake rather than quoting yours.

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Offline Geezer

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« Reply #105 on: 29/10/2011 17:11:02 »
I don't think you would get a meaningful patent for your idea as it touches on .........

Actually, I'm not interested in obtaining a patent for something like this. I was really only interested in seeing if it's possible to come up with something that might have a snowball's chance of actually working. The fact that there is something similar to this already wouldn't surprise me, because this is one of the few ways it's actually going to work. If there is anything novel about this idea (which I doubt), I'm quite happy that I've prevented anyone else from patenting it.

There is little point in obtaining a patent on an alternative method of doing something that offers no advantages over an existing method. Also, "kitchen sink" patents that attempt to combine all sorts of existing techniques are pretty much worthless because it's too easy to bypass their claims, whereas some of the best patents are those that overcome a problem that the prior art has failed to deal with.
There ain'ta no sanity clause, and there ain'ta no centrifugal force ĉther.

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Offline Geezer

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« Reply #106 on: 29/10/2011 20:30:52 »
I took a shot at an economy version.

[attachment=15475]

This might help to address BC's concern that you need a big strong floaty thing, though it does still need to be big and floaty.

The hydraulic ram is now submerged and attached to the float and the anchor by cables or chains. The big floaty thing is full of air under enough pressure to prevent it collapsing at that depth. Not shown in much detail (cos I was too lazy to draw it) is a net-like thing that surrounds the spherical float and spreads the load from the ram over its upper surface. Maybe that's made of Kevlar, or carbon fibre?

Exactly what the float is made of is a bit of a mystery. I suspect it could be from any number of things. The important thing is that the air must not be able to leak out quickly, although a small amount of leakage could be tolerated and made up from a supply of compressed air.

Obviously the ram should be enclosed to keep seawater away from it, particularly the rod.

Interestingly, the control system is remarkably simple. All it has to do is keep the hydraulic pressure in the ram at a minimum pressure. If the tide is rising, the pressure tends to rise, so the system sends fluid to the hydraulic motor to relieve the pressure. When the tide if falling, the system pumps fluid into the ram to maintain the minimum pressure. That ensures the float maintains a constant level relative to the water surface.
 


« Last Edit: 30/10/2011 01:10:43 by Geezer »
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Offline Bored chemist

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« Reply #107 on: 30/10/2011 10:15:04 »
Mootle,
The biggest (by far) uncertainty in the revenue is some theoretical subsidy that a government might pay.
You seem to think the revenue stream is adequate.
I don't.
The numbers (uncertain though they are) are on my side.
It wasn't going to make money, even with a stupidly large subsidy.
Please disregard all previous signatures.

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Offline Mootle

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« Reply #108 on: 30/10/2011 11:09:02 »
Mootle,
The biggest (by far) uncertainty in the revenue is some theoretical subsidy that a government might pay.
You seem to think the revenue stream is adequate.
I don't.
The numbers (uncertain though they are) are on my side.
It wasn't going to make money, even with a stupidly large subsidy.

What ever you think, the government incentives are extant - if you are a citizen of the UK you're already paying for the policy to which Tony Blair committed the UK to many years ago. Energy suppliers are required to include a mix of renewables as part of their portfolio in order to retain their licence to operate.

It is absurd to assert that the numbers fall on either side. Math doesn't subscribe to favouritism, the numbers will be what they are, when the time comes - further dialogue in this regard is futile.

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Offline Bored chemist

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« Reply #109 on: 30/10/2011 13:20:31 »
"What ever you think, the government incentives are extant - if you are a citizen of the UK you're already paying for the policy to which Tony Blair committed the UK to many years ago."
I'm a UK citizen. I'm aware of the analogous subsidy for some forms of renewable energy.
I'm also aware that the original planned subsidy is due to come to an end.
The current government is not enthusiastic about spending money (in general) so I wouldn't like to build a business case on the current subsidy.

On one side we have a cost measured inn tens or hundreds of millions. On the other we have a reliable revenue measured in hundreds of thousands per year.
The numbers on one side really are bigger than those on the other.
The side of the argument they favour is clearly the side that says "This is silly and will never work in a month of Sundays".
As far as I can tell, that's my side, not yours.

I know the suppliers are required to use renewables.
But they are not stupid.
I can go into town and pay £150 for a 50W wind turbine. so, with no economies of scale or government subsidy I can get power for £3 per W.
http://www.maplin.co.uk/50w-telescopic-vertical-axis-wind-turbine-396269
Your system produced something like 0.8MW ( ignoring efficiencies)
I could get that from 16000 similar wind turbines (it would be a stupid way to do it, but I could). That would cost me £2.4M
Or I could spend something like 10 or 100 times more on untested technology.
How stupid would I have to be to do that?



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Offline Mootle

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« Reply #110 on: 30/10/2011 13:40:43 »
"What ever you think, the government incentives are extant - if you are a citizen of the UK you're already paying for the policy to which Tony Blair committed the UK to many years ago."
I'm a UK citizen. I'm aware of the analogous subsidy for some forms of renewable energy.
I'm also aware that the original planned subsidy is due to come to an end.
The current government is not enthusiastic about spending money (in general) so I wouldn't like to build a business case on the current subsidy.

On one side we have a cost measured inn tens or hundreds of millions. On the other we have a reliable revenue measured in hundreds of thousands per year.
The numbers on one side really are bigger than those on the other.
The side of the argument they favour is clearly the side that says "This is silly and will never work in a month of Sundays".
As far as I can tell, that's my side, not yours.

I know the suppliers are required to use renewables.
But they are not stupid.
I can go into town and pay £150 for a 50W wind turbine. so, with no economies of scale or government subsidy I can get power for £3 per W.
http://www.maplin.co.uk/50w-telescopic-vertical-axis-wind-turbine-396269
Your system produced something like 0.8MW ( ignoring efficiencies)
I could get that from 16000 similar wind turbines (it would be a stupid way to do it, but I could). That would cost me £2.4M
Or I could spend something like 10 or 100 times more on untested technology.
How stupid would I have to be to do that?

More speculation, a sizable chunk of nonesense and another serving of sarcasm but the fact remains that only time will tell.

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Offline Bored chemist

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« Reply #111 on: 30/10/2011 15:11:42 »
The power generation rates are not speculative.
The price of the wind turbines are not speculative.
The only speculation and nonsense are your strange idea that your system will somehow become vastly cheaper than it is.
Time has, for all practical purposes, already told.
You (almost certainly) can't make one vital component of your system for the money it would cost to set up a known system.
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Offline Geezer

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« Reply #112 on: 30/10/2011 19:07:42 »
I was quite encouraged by the "economy version", so I thought it might actually be useful in remote locations if it wasn't too expensive. I started with the assumption that I wanted to power a single 13A 230V outlet on Muckle Flugga - not continuously mind you - only while the tide was coming in at its maximum rate.

Assumptions:
The tide is rising at 0.15 mm/s.
Overall conversion efficiency to electricity is 60%

So,
Work is being done by rising tide at 4.6kJ/s
Force on ram is 4600/0.00015 = 30MN
Displacement of float is 30/10 = 3 Mega kg or 3000 tonnes.

The large floaty thing still needs to displace the equivalent of 1.5 million two litre soda bottles, and the anchor better weigh about 6000 tonnes.

Unless I mucked something up here (which is highly possible) this scheme is Le canard mort.
There ain'ta no sanity clause, and there ain'ta no centrifugal force ĉther.

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Offline Bored chemist

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« Reply #113 on: 30/10/2011 19:41:51 »
You might get an Arts Council grant to cover the cost.
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Offline Mootle

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« Reply #114 on: 30/10/2011 19:51:19 »
The power generation rates are not speculative.

What seasonal efficiency do you think your turbine will achieve. A quick google of micro wind turbines will tell you that your own gut feeling for making such a comparison was indeed 'stupid'.

The price of the wind turbines are not speculative.

What do you think the installed cost of your turbine would be?

The only speculation and nonsense are your strange idea that your system will somehow become vastly cheaper than it is.


I haven't developed the design as yet, let alone costed it so how can it become vastly cheaper. I've set out why the the reused value of 7 large tankers is not a useful representation of the cost of the pontoon. Do you honestly think that repeating the same argument changes anything?


Time has, for all practical purposes, already told.
You (almost certainly) can't make one vital component of your system for the money it would cost to set
up a known system.

Only time will tell what shape the system design takes and thereafter the cost.

Only time will tell what revenue can be achieved by adopting a power mix.

Only time will tell what changes are made to the extant government incentive schemes.

You refusal to accept these basic premises are baffling.

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Offline Mootle

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« Reply #115 on: 30/10/2011 20:35:21 »
I was quite encouraged by the "economy version", so I thought it might actually be useful in remote locations if it wasn't too expensive. I started with the assumption that I wanted to power a single 13A 230V outlet on Muckle Flugga - not continuously mind you - only while the tide was coming in at its maximum rate.

Assumptions:
The tide is rising at 0.15 mm/s.
Overall conversion efficiency to electricity is 60%

So,
Work is being done by rising tide at 4.6kJ/s
Force on ram is 4600/0.00015 = 30MN
Displacement of float is 30/10 = 3 Mega kg or 3000 tonnes.

The large floaty thing still needs to displace the equivalent of 1.5 million two litre soda bottles, and the anchor better weigh about 6000 tonnes.

Unless I mucked something up here (which is highly possible) this scheme is Le canard mort.

Your system wasn't fully defined so I've run a rough order calculation for a continuous 3kW demand.

For this purpose we would need (2) buoyancy engines.

Each system would require storage for 12hrs and a flow rate of ca. 0.0071m3/s.

A generator inlet CSA of 0.017m2 would give the flow rate based on a working head of 50m assuming an 85% turbine / generator efficiency.

Thus, the required Storage Vessel volume would be ca. 300m3, say a cylindrical tank ca. 10m diam * 4m.

Based on a 25:1 gearing ratio each Pontoon volume would be ca. 7,500m3, say equivalent to a rectangular tank ca. 65 * 20 * 6m.

Generation phases would be offset assuming a typical (2) tide per day cycle. Based on this arrangement the Pontoon loading would not occur simultaneously. Therefore, there is scope to engineer an arrangement such that both Storage Vessels operate from one Pontoon, which carries a number of operational and financial advantages.

Tidal range is assumed as 2m.

I don't plan to use a traditional anchor. 

This system is not optimised for revenue recovery but rather to meet a continuous demand in the absence of any energy mix.

No allowance has been made for gross volume.

If a continuous power supply isn't required I expect an hybrid solar PV / wind system would be a more cost effective solution for this particular application.

However, if it's important that your pc and lights continue to operate during the night time you might want to consider the Buoyancy Engine.
« Last Edit: 30/10/2011 20:40:33 by Mootle »

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Offline Bored chemist

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« Reply #116 on: 30/10/2011 21:10:21 »
"What seasonal efficiency do you think your turbine will achieve. A quick google of micro wind turbines will tell you that your own gut feeling for making such a comparison was indeed 'stupid'."
Yes, But I did it on purpose.
I deliberately chose a ridiculous system and I ignored obvious  factors like the fact that you wouldn't use such small generators and also that you would qualify for a bulk discount. I also ignored the fact that these things only run when the wind blows. Of course, the importance of that depends on where you put them. Where I live the mean wind speed isn't high enough to turn that generator.

However, in spite of all that - which as you say makes them stupid.
The purchase cost is still less than your idea. Not marginally less, not a bit less, but a whole lot less. Something like £2.4M rather than tens or hundreds of millions. You keep saying that time will tell what the true cost will be. Fair enough, but can you (as I have asked before) come up with some explanation of why you feel that you will be able to make this cheaper than, for example, a scarp supertanker?


Incidentally, you say
"I don't plan to use a traditional anchor. "
presumably that means you plan to use something more expensive or you think that the professionals have been getting it wrong all this time.

Your idea that the government will suddenly decide to fund your dead duck rather than, for example this live one is the baffling thing
http://en.wikipedia.org/wiki/Salter's_duck

The government thinks renewable power is a good thing. So do I, but that's not the point.
So they will fund schemes to generate it.
But they won't fund any old scheme. They schemes have to compete against each other.
Since there's no way that you can build yours for less than roughly 10 times the cost of a bunch of stupidly inefficient ones which deliver the same power, there's no incentive for them to fund it.
You will always make a loss on this.
« Last Edit: 30/10/2011 21:25:15 by Bored chemist »
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Offline Geezer

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« Reply #117 on: 30/10/2011 22:00:41 »
Your system wasn't fully defined so I've run a rough order calculation for a continuous 3kW demand.

I encourage you to scrutinize my numbers very carefully. Either I mucked them up, or you are stiffing yourself by making the pontoons twice as large as they need to be.

As I mentioned a couple of times already, and as any engineer worth their salt will point out, it's generally a really good idea to figure out how much energy is actually going into a system so that we can compare and contrast it with the amount of energy that is coming out of the system. When we figure it all out, net energy should be pretty close to zero.
« Last Edit: 30/10/2011 22:03:44 by Geezer »
There ain'ta no sanity clause, and there ain'ta no centrifugal force ĉther.

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Offline Geezer

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« Reply #118 on: 30/10/2011 23:40:59 »
You might get an Arts Council grant to cover the cost.


Strangely enough, I did consider that possibility.

My application to the Arts Council includes a twenty meter bust of Julius Geezer made from crushed beer cans that sits atop the big floaty thing. The residents of Muckle Flugga are bound to appreciate it.

I have named my artistic endeavour "Roman in the Gloamin"
« Last Edit: 31/10/2011 08:11:53 by Geezer »
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Offline Mootle

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« Reply #119 on: 01/11/2011 19:36:16 »
"What seasonal efficiency do you think your turbine will achieve. A quick google of micro wind turbines will tell you that your own gut feeling for making such a comparison was indeed 'stupid'."
Yes, But I did it on purpose.
I deliberately chose a ridiculous system and I ignored obvious  factors like the fact that you wouldn't use such small generators and also that you would qualify for a bulk discount. I also ignored the fact that these things only run when the wind blows. Of course, the importance of that depends on where you put them. Where I live the mean wind speed isn't high enough to turn that generator.

However, in spite of all that - which as you say makes them stupid.
The purchase cost is still less than your idea. Not marginally less, not a bit less, but a whole lot less. Something like £2.4M rather than tens or hundreds of millions. You keep saying that time will tell what the true cost will be. Fair enough, but can you (as I have asked before) come up with some explanation of why you feel that you will be able to make this cheaper than, for example, a scarp supertanker?


Incidentally, you say
"I don't plan to use a traditional anchor. "
presumably that means you plan to use something more expensive or you think that the professionals have been getting it wrong all this time.

Your idea that the government will suddenly decide to fund your dead duck rather than, for example this live one is the baffling thing
http://en.wikipedia.org/wiki/Salter's_duck

The government thinks renewable power is a good thing. So do I, but that's not the point.
So they will fund schemes to generate it.
But they won't fund any old scheme. They schemes have to compete against each other.
Since there's no way that you can build yours for less than roughly 10 times the cost of a bunch of stupidly inefficient ones which deliver the same power, there's no incentive for them to fund it.
You will always make a loss on this.

You really don't get this at all. Whilst it is interesting to get 'points of view' it does get a little tiresome going over the same points. Suffice to say I will use meaningful data for the business case rather than ill informed guess work. I don't see that this should be such an affront to your sensibilities, after all I've made no claims as to the system costs to date.

Despite, what you think this is a new idea so anchorage for such a development would need an innovative approach. Typically, the loading is compressive rather than tensile and the forces involved will be huge. As I indicated previously, I will show the principles on a construction animation once I get around to it. My objective is to attain healthy savings against traditional marine anchorage methods whilst improving the sustainability of such a scheme.
« Last Edit: 01/11/2011 19:40:04 by Mootle »

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Offline Mootle

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« Reply #120 on: 01/11/2011 20:00:13 »
Your system wasn't fully defined so I've run a rough order calculation for a continuous 3kW demand.

I encourage you to scrutinize my numbers very carefully. Either I mucked them up, or you are stiffing yourself by making the pontoons twice as large as they need to be.

As I mentioned a couple of times already, and as any engineer worth their salt will point out, it's generally a really good idea to figure out how much energy is actually going into a system so that we can compare and contrast it with the amount of energy that is coming out of the system. When we figure it all out, net energy should be pretty close to zero.

As I indicated your system wasn't fully defined.

I find it better to start with a generator rating, this is used to establish the Storage Volume, once the generation time is determined. Then comes the Pontoon sizing based on the selected gearing ratio.

I've done a rough and ready estimate based on a system which will produce 3kW continuously. Our system efficiency may vary but otherwise I would expect the figures to work out. This increases the Storage Vessel volume which will in turn increase the Pontoon volume.

Since you didn't define the operating time I thought this was preferable to second guessing what you've allowed for although in broad terms, for a 3,000m3 Pontoon a matched Storage Vessel of 120m3 @ 25:1 gearing would be estimated as little over 4 1/2hrs of generation for your stated load.
« Last Edit: 01/11/2011 20:09:07 by Mootle »

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Offline Geezer

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« Reply #121 on: 01/11/2011 20:44:37 »
I find it better to start with a generator rating, this is used to establish the Storage Volume, once the generation time is determined. Then comes the Pontoon sizing based on the selected gearing ratio.

Yes, but it looks as if you are basing the storage volume based on the way you believe your invention ought to work. If you don't determine the energy supplied by the tide directly, you have no means of cross checking your answer. It's not as if it's difficult to determine the energy input either.

I simply determined the power input by the maximum tidal rate (which, admittedly, I did sort of noodle) and derated it according to a efficiency factor. My calculation pays absolutely no attention to gear ratios etc. because they are completely irrelevant.

More specifically;

Power input x efficiency = power output.
There ain'ta no sanity clause, and there ain'ta no centrifugal force ĉther.

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Offline Mootle

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« Reply #122 on: 01/11/2011 21:01:39 »
I find it better to start with a generator rating, this is used to establish the Storage Volume, once the generation time is determined. Then comes the Pontoon sizing based on the selected gearing ratio.

Yes, but it looks as if you are basing the storage volume based on the way you believe your invention ought to work. If you don't determine the energy supplied by the tide directly, you have no means of cross checking your answer. It's not as if it's difficult to determine the energy input either.

I simply determined the power input by the maximum tidal rate (which, admittedly, I did sort of noodle) and derated it according to a efficiency factor. My calculation pays absolutely no attention to gear ratios etc. because they are completely irrelevant.

More specifically;

Power input x efficiency = power output.

It has been demonstrated that all things being equal and accounting for efficiency it really doesn't matter which way you work out the energy balance.

Generator work done = Pontoon work done = Storage Vessel work done.

I'd rather hoped that we had moved on from the energy balance. From a economy of scale perspective this scheme doesn't make sense for the buoyancy engine but I would agree that it is useful to look at the small scale as it can sometimes help to quantify matters. 
« Last Edit: 01/11/2011 21:03:44 by Mootle »

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Offline Bored chemist

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« Reply #123 on: 01/11/2011 21:02:13 »
The payback time of this project will certainly be longer than the lifetime of a government.
The only way it could work is with government backing (because it produces electricity that's a lot more expensive than the current wholesale rate).
So, when you say "Suffice to say I will use meaningful data for the business case rather than ill informed guess work. " all you can mean is that you will use your guess of what government subsidy will be available, rather than my guess.

Fair enough, but don't pretend it's anything but a guess.
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Offline Mootle

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« Reply #124 on: 01/11/2011 21:12:37 »
The payback time of this project will certainly be longer than the lifetime of a government.
The only way it could work is with government backing (because it produces electricity that's a lot more expensive than the current wholesale rate).
So, when you say "Suffice to say I will use meaningful data for the business case rather than ill informed guess work. " all you can mean is that you will use your guess of what government subsidy will be available, rather than my guess.

Fair enough, but don't pretend it's anything but a guess.

I'm not pretending anything. When writing a business case the revenue is calculated based on the extant government incentives.

It is true that the FIT scheme is under review and as such that uncertainty would have to be declared. However, would you not agree that if the Buoyancy Engine was set to work today, the given revenue figures would be achievable according to the rough order energy balance that has been agreed?

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« Reply #125 on: 01/11/2011 21:30:46 »

Generator work done = Pontoon work done = Storage Vessel work done.



IMHO, that's a dangerous way to look at it, and it can easiliy lead to confusion, QED.

It should be;

Tide work done = all lost energy + captured energy.

The tide is the source of the energy, not the pontoon.
There ain'ta no sanity clause, and there ain'ta no centrifugal force ĉther.

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« Reply #126 on: 01/11/2011 22:03:02 »

Generator work done = Pontoon work done = Storage Vessel work done.



IMHO, that's a dangerous way to look at it, and it can easiliy lead to confusion, QED.

It should be;

Tide work done = all lost energy + captured energy.

The tide is the source of the energy, not the pontoon.

You're leaning against an open door here - my point is that it works out all ways around, the only question mark relates to the system efficiency. Turbines and generators can work very efficiently if correctly matched to the application and this should be the main input for a well designed system. It is more difficult to establish the overall system efficiency. This will be a function of the the pulley system, the additional buoyancy needed to drive the ascent phase, allowances for coral growth etc, trimming losses (governing swell,) cable stretch, Pontoon sinkage, down time for maintenance / unsuitable operating conditions.... 

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« Reply #127 on: 01/11/2011 22:11:33 »
"would you not agree that if the Buoyancy Engine was set to work today, the given revenue figures would be achievable according to the rough order energy balance that has been agreed?"
My deliberately absurdly high estimate of the combined tariffs and subsidies was the equivalent of 4 times the actual value of the electricity produced.
I think your figures came out at something like half that figure.
It doesn't matter because, as I pointed out, many times,

Unless you can show how you are suddenly going to make this scheme a lot cheaper, it will never "break even" because the guessed revenues will never exceed the cost of paying the interest on the capital investment.

Worse, even if you could make it break even, it would still be a couple of orders of magnitude more expensive that just buying an absurdly expensive system.

I have asked the same question plenty of times and you don't seem to understand the importance of it.
How are you going to make your system ten times cheaper than the scrap value of the pontoon?


Oh, BTW, I write, and review business cases for the government.

We do take account of the fact that the plug might get pulled and, if that looks likely, we simply don't support the work. We don't do work that is likely to depend on long term support because that's not a good use of the investor's capital. So that's "When writing a business case the revenue is calculated based on the extant government incentives." scuppered.
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« Reply #128 on: 02/11/2011 04:53:44 »

Generator work done = Pontoon work done = Storage Vessel work done.



IMHO, that's a dangerous way to look at it, and it can easiliy lead to confusion, QED.

It should be;

Tide work done = all lost energy + captured energy.

The tide is the source of the energy, not the pontoon.

You're leaning against an open door here - my point is that it works out all ways around, the only question mark relates to the system efficiency. Turbines and generators can work very efficiently if correctly matched to the application and this should be the main input for a well designed system. It is more difficult to establish the overall system efficiency. This will be a function of the the pulley system, the additional buoyancy needed to drive the ascent phase, allowances for coral growth etc, trimming losses (governing swell,) cable stretch, Pontoon sinkage, down time for maintenance / unsuitable operating conditions.... 

Your pontoons are capable of producing 588.6MJ in 24 hours which means your efficiency is 44.1%

How does that strike you?

« Last Edit: 02/11/2011 06:21:01 by Geezer »
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« Reply #129 on: 05/11/2011 09:06:35 »

Generator work done = Pontoon work done = Storage Vessel work done.



IMHO, that's a dangerous way to look at it, and it can easiliy lead to confusion, QED.

It should be;

Tide work done = all lost energy + captured energy.

The tide is the source of the energy, not the pontoon.

You're leaning against an open door here - my point is that it works out all ways around, the only question mark relates to the system efficiency. Turbines and generators can work very efficiently if correctly matched to the application and this should be the main input for a well designed system. It is more difficult to establish the overall system efficiency. This will be a function of the the pulley system, the additional buoyancy needed to drive the ascent phase, allowances for coral growth etc, trimming losses (governing swell,) cable stretch, Pontoon sinkage, down time for maintenance / unsuitable operating conditions.... 

Your pontoons are capable of producing 588.6MJ in 24 hours which means your efficiency is 44.1%

How does that strike you?


Without trying to second guess your calculations did you take into account my comment:

'Therefore, there is scope to engineer an arrangement such that both Storage Vessels operate from one Pontoon, which carries a number of operational and financial advantages.'

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« Reply #130 on: 05/11/2011 09:21:43 »
"would you not agree that if the Buoyancy Engine was set to work today, the given revenue figures would be achievable according to the rough order energy balance that has been agreed?"
My deliberately absurdly high estimate of the combined tariffs and subsidies was the equivalent of 4 times the actual value of the electricity produced.
I think your figures came out at something like half that figure.
It doesn't matter because, as I pointed out, many times,

Unless you can show how you are suddenly going to make this scheme a lot cheaper, it will never "break even" because the guessed revenues will never exceed the cost of paying the interest on the capital investment.

Worse, even if you could make it break even, it would still be a couple of orders of magnitude more expensive that just buying an absurdly expensive system.

I have asked the same question plenty of times and you don't seem to understand the importance of it.
How are you going to make your system ten times cheaper than the scrap value of the pontoon?


Oh, BTW, I write, and review business cases for the government.

We do take account of the fact that the plug might get pulled and, if that looks likely, we simply don't support the work. We don't do work that is likely to depend on long term support because that's not a good use of the investor's capital. So that's "When writing a business case the revenue is calculated based on the extant government incentives." scuppered.

You are presupposing which way the future FIT scheme will go. I've already indicated that the current uncertainty would need to be declared:
 
'It is true that the FIT scheme is under review and as such that uncertainty would have to be declared.'

Your difficulty comes from not being able to distinguish points of view from fact. The fact is no costing claims have been made. I've set out why I don't think the assumptions made are reliable. For now I will press on with the scaled model animation, after which reasonably accurate costs can be established.

We seem to be going around in circles so unless anyone has some new questions I declare myself out of the thread for the time being.

Once again, thanks to all that took the time to comment.

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« Reply #131 on: 05/11/2011 14:21:39 »
This isn't a POV, it's a fact.
I can get the same nominal electricity generating potential as your machine for something like £2.4M

It's also renewable power, so it would presumably get the same FIT. (Granted that is a POV, but I think it's a reasonable one.)
So, unless you can build your scheme for less than that sum your system isn't financially viable.

It's also a fact that your rig needs a big pontoon.
It's a reasonable POV to say that it's in many ways similar to a ship. The stresses on it are different, but comparable (actually they are probably more difficult to manage).

It's not an unreasonable POV that shipbuilders know what they are doing.
They use steel so it's fair to say that steel is a good material to use in terms of cost versus practicality.
SO it's not unreasonable to conclude tat your system, which is quite like a ship, will have a cost comparable with a ship of the same displacement.

I have asked several times what you could do to make it significantly cheaper than a ship of that size. You don't seem to have offered any answer to that.
So, it seems that you must agree that the cost estimate is not absurdly wrong.

However that means that, if someone built your system they could sell it for the scrap value.
That value is rather more than £2.4M. Probably one or two orders of magnitude more.
So they could sell it for scrap, buy the wind turbines, sell the same power back to the grid for the same  money and pocket a huge sum of money.

Let me know which of my assumptions you feel is actually unreasonable, rather than just pointing out that they are assumptions. I know they are not cast in stone, but the point is that they only need to be very roughly correct to show that your system will fail to cover its cost.

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« Reply #132 on: 06/11/2011 01:29:43 »

Generator work done = Pontoon work done = Storage Vessel work done.



IMHO, that's a dangerous way to look at it, and it can easiliy lead to confusion, QED.

It should be;

Tide work done = all lost energy + captured energy.

The tide is the source of the energy, not the pontoon.

You're leaning against an open door here - my point is that it works out all ways around, the only question mark relates to the system efficiency. Turbines and generators can work very efficiently if correctly matched to the application and this should be the main input for a well designed system. It is more difficult to establish the overall system efficiency. This will be a function of the the pulley system, the additional buoyancy needed to drive the ascent phase, allowances for coral growth etc, trimming losses (governing swell,) cable stretch, Pontoon sinkage, down time for maintenance / unsuitable operating conditions.... 

Your pontoons are capable of producing 588.6MJ in 24 hours which means your efficiency is 44.1%

How does that strike you?


Without trying to second guess your calculations did you take into account my comment:

'Therefore, there is scope to engineer an arrangement such that both Storage Vessels operate from one Pontoon, which carries a number of operational and financial advantages.'


Yes, I did. As you didn't specify its displacement, I assumed it was twice the displacement of the two smaller ones. If you knew it was possible to generate the power output with half the total displacement, I would have thought you would have made that clear.

My calculation was simply the energy output over the maximum energy input based on the displacements and the tide.
There ain'ta no sanity clause, and there ain'ta no centrifugal force ĉther.

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« Reply #133 on: 06/11/2011 18:39:59 »
This isn't a POV, it's a fact.
I can get the same nominal electricity generating potential as your machine for something like £2.4M

It's also renewable power, so it would presumably get the same FIT. (Granted that is a POV, but I think it's a reasonable one.)
So, unless you can build your scheme for less than that sum your system isn't financially viable.

It's also a fact that your rig needs a big pontoon.
It's a reasonable POV to say that it's in many ways similar to a ship. The stresses on it are different, but comparable (actually they are probably more difficult to manage).

It's not an unreasonable POV that shipbuilders know what they are doing.
They use steel so it's fair to say that steel is a good material to use in terms of cost versus practicality.
SO it's not unreasonable to conclude tat your system, which is quite like a ship, will have a cost comparable with a ship of the same displacement.

I have asked several times what you could do to make it significantly cheaper than a ship of that size. You don't seem to have offered any answer to that.
So, it seems that you must agree that the cost estimate is not absurdly wrong.

However that means that, if someone built your system they could sell it for the scrap value.
That value is rather more than £2.4M. Probably one or two orders of magnitude more.
So they could sell it for scrap, buy the wind turbines, sell the same power back to the grid for the same  money and pocket a huge sum of money.

Let me know which of my assumptions you feel is actually unreasonable, rather than just pointing out that they are assumptions. I know they are not cast in stone, but the point is that they only need to be very roughly correct to show that your system will fail to cover its cost.

For the umpteenth time, I do not think it's a good idea to make an estimate until a design has been done. I have offered various answers to your questions that seem perfectly reasonable to me but you have chosen to disregard them.

I fail to see how you can offer up the comparison with any kind of seriousness. It is so flawed that it isn't worth consideration even if you did include things like installation and whether it could actually provide load when you need it.

Perhaps we should all purchase a domestic petrol powered generator rather than invest in our energy infrastructure since those power stations would probably represent poor value for money by comparison. 
« Last Edit: 06/11/2011 18:41:45 by Mootle »

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« Reply #134 on: 06/11/2011 18:50:33 »
Yes, I did. As you didn't specify its displacement, I assumed it was twice the displacement of the two smaller ones. If you knew it was possible to generate the power output with half the total displacement, I would have thought you would have made that clear.

My calculation was simply the energy output over the maximum energy input based on the displacements and the tide.

I thought I did (3rd time lucky):
'Therefore, there is scope to engineer an arrangement such that both Storage Vessels operate from one Pontoon, which carries a number of operational and financial advantages.'

If you show your workings I can review further. The problem I have is that even when you are presented with irrefutable evidence you still don't concede points so I have no intention of trying to second guess what you have calculated.

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« Reply #135 on: 06/11/2011 19:47:53 »
Yes, I did. As you didn't specify its displacement, I assumed it was twice the displacement of the two smaller ones. If you knew it was possible to generate the power output with half the total displacement, I would have thought you would have made that clear.

My calculation was simply the energy output over the maximum energy input based on the displacements and the tide.

I thought I did (3rd time lucky):
'Therefore, there is scope to engineer an arrangement such that both Storage Vessels operate from one Pontoon, which carries a number of operational and financial advantages.'

If you show your workings I can review further. The problem I have is that even when you are presented with irrefutable evidence you still don't concede points so I have no intention of trying to second guess what you have calculated.

OK - here you go.

Quote
Based on a 25:1 gearing ratio each Pontoon volume would be ca. 7,500m3
Tidal range is assumed as 2m.

Total displacement 2 x 7500 = 15,000m3, or 15,000,000kg (ignoring the salt in the water)
Therefore, max force is 147.2MN
Max work in 24 hours is 147.2 x 4 = 588.6MJ = 588,600kJ
Max work per second is 588,600/86,400 = 6.81kJ
Max power in = 6.81 kW
Power out = 3.0kw
Efficiency = 44.1%

(Or are you assuming one of the pontoons is going to spring a leak and sink?)
« Last Edit: 06/11/2011 20:00:56 by Geezer »
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« Reply #136 on: 06/11/2011 20:58:43 »
OK, so I first asked "What developments would you put on your "wish list" that would actually make your system anything other than a white elephant?"
here
http://www.thenakedscientists.com/forum/index.php?topic=41578.msg370908#msg370908
Your reply was "there are various aspects of this application that we haven't touched on that would require development. "

So again I asked
"Clearly, to make your idea work there has to be a major change somewhere and that change has to make your system a lot cheaper.

What do you think can make it work?"
And I repeated essentially the same question
"It's still not going to work unless there's some magic change in the economics so I'd still like to see Mootle's answer to my question.
What can you change to make this idea work?"

And you said this
"As I've said before there are many developmental steps required.

I agree, steel prices are only likely to go up with time (as energy costs soar). This is one reason for aiming to minimise the use of steel in the system design.

One of the biggest challenges will be the anchorage. I don't think the use of large quantities of concrete will be sustainable or cost effective. I'm working on a construction animation to show the sequences involved and would post this in due course - house rules permitting"

So you say you won't use steel because it's expensive. It is however in practical terms quite cheap. That's why shipbuilders use it.

And you say you won't use concrete for the footings.
Good luck finding anything strong enough, heavy enough and cheaper than concrete.
So, thus far you have yet to really answer the question. YOu have made a couple of questionable comments about what you won't do (i.e. use steel or concrete), but nothing about what you will do.

This suggestion "I'm researching the possibility of reinforced plastics for the main base." was kicked into touch by Geezer when he pointed out that it's going to need to be very strong. Anyway I don't think reinforced plastics are much cheaper than steel if you actually need much strength.


And you don't seem to have addressed the issue of tying the pulleys down.
"Seriously, if they still use concrete for building things like the Thames Barrier, why do you think plastic might be better?
Do you think they are idiots?"

You don't seem to have replied to that. What you next said on the subject (unless I missed something was
"I've set out why the the reused value of 7 large tankers is not a useful representation of the cost of the pontoon. "
which is unfortunate since, so far as I can see, you didn't (though you did say you had deleted a post- perhaps it was there that you explained why your big strong floaty thing would be cheaper than someone else's design of big strong floaty thing.)

Again you say things like "I don't plan to use a traditional anchor. " without saying what you will use and ignoring the fact that traditional anchors wouldn't have got  to be traditional if they didn't work.

So, once again I asked " Fair enough, but can you (as I have asked before) come up with some explanation of why you feel that you will be able to make this cheaper than, for example, a scarp supertanker?"

And your reply was "Whilst it is interesting to get 'points of view' it does get a little tiresome going over the same points."
You don't seem to have understood that the way to avoid the tiresome repetition of a question is simply to answer it. Saying "this is a new idea so anchorage for such a development would need an innovative approach." doesn't actually tell us anything.

So, once again I asked
"How are you going to make your system ten times cheaper than the scrap value of the pontoon?"

And what do I get in reply?
I get this " I have offered various answers to your questions that seem perfectly reasonable to me but you have chosen to disregard them. "

Well, they may seem reasonable to you but from my point of view they seem to lack a fairly fundamental aspect.
You still haven't said what you are going to do to make this work for about 100 times less than the scrap value of the pontoon.

This is a science website.
People who put forward ideas are expected to answer questions asked about those ideas.

If I have missed an answer of the form "I will do (whatever) which is cheaper than using an old oil tanker" then please point it out to me
I'm not going to accept an answer that says "I haven't costed it yet" because that's the whole point; several of us have costed it and it's preposterously expensive.
I'm also not going to accept an answer that says "I will sprinkle magic pixie dust on the cost and make it go away" or, the roughly equivalent " I will need to do some research in reinforced plastics" or "I won't use a traditional anchor".

Now I challenge you to answer the question in a straightforward manner or leave.

How will you make this rig cheap enough that the revenue will, at least, service the loan for building it?









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« Reply #137 on: 08/11/2011 20:43:01 »
Quote
Max power in = 6.81 kW
Power out = 3.0kw
Efficiency = 44.1%
I have'nt followed the whole thread, it's a bit convoluted. Please explain this efficiency part?
« Last Edit: 08/11/2011 20:50:51 by johan_M »

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« Reply #138 on: 08/11/2011 21:15:08 »
Quote
Max power in = 6.81 kW
Power out = 3.0kw
Efficiency = 44.1%
I have'nt followed the whole thread, it's a bit convoluted. Please explain this efficiency part?

Which part of it do you not understand?
There ain'ta no sanity clause, and there ain'ta no centrifugal force ĉther.

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« Reply #139 on: 08/11/2011 23:19:20 »
Quote
Max power in = 6.81 kW
Power out = 3.0kw
Efficiency = 44.1%
I have'nt followed the whole thread, it's a bit convoluted. Please explain this efficiency part?


Which part of it do you not understand?

Is it possible that the missing link is "efficiency = power out/power in" ?
1 4 6 4 1
4 4 9 4 4     
a perfect perfect square square
6 9 6 9 6
4 4 9 4 4
1 4 6 4 1

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« Reply #140 on: 08/11/2011 23:57:38 »
Quote
Max power in = 6.81 kW
Power out = 3.0kw
Efficiency = 44.1%
I have'nt followed the whole thread, it's a bit convoluted. Please explain this efficiency part?


Which part of it do you not understand?

Is it possible that the missing link is "efficiency = power out/power in" ?


It's actually a bit more complicated  [:D]

All the power never actually "went in". The system has the potential of acquiring a lot more energy from the tide than it outputs, so it's more a measure of volumetric, or displacement, efficiency.

The trouble with efficiencies is they can refer to lots of different measurements. If you ever want to start a really heated argument in a pub, efficiency is a good way to do it (it's usually a good idea to leave shortly after you start the argument [;D])
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« Reply #141 on: 09/11/2011 00:41:49 »
What do you mean by displacement efficiency? Where does the lost energy go?can you give a simple example?

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« Reply #142 on: 09/11/2011 04:01:16 »
What do you mean by displacement efficiency? Where does the lost energy go?can you give a simple example?

There is no lost energy (well, there will be some due to parasitic losses like friction etc.) but this measurement is not about energy efficiency. We're evaluating the efficient use of the volume of the pontoon (which is a good thing to do because the pontoon is a very expensive part of the system.)

Based on the total possible energy in versus actual energy out, the pontoons might only be half the size (to displace the required amount of water), hence an efficiency of less than 50%. This also tells us that the pontoons are probably twice as expensive as they need to be.

The thing about efficiency is that it can refer to all sorts of things, not just energy.
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« Reply #143 on: 11/11/2011 20:26:17 »
Yes, I did. As you didn't specify its displacement, I assumed it was twice the displacement of the two smaller ones. If you knew it was possible to generate the power output with half the total displacement, I would have thought you would have made that clear.

My calculation was simply the energy output over the maximum energy input based on the displacements and the tide.

I thought I did (3rd time lucky):
'Therefore, there is scope to engineer an arrangement such that both Storage Vessels operate from one Pontoon, which carries a number of operational and financial advantages.'

If you show your workings I can review further. The problem I have is that even when you are presented with irrefutable evidence you still don't concede points so I have no intention of trying to second guess what you have calculated.

OK - here you go.

Quote
Based on a 25:1 gearing ratio each Pontoon volume would be ca. 7,500m3
Tidal range is assumed as 2m.

Total displacement 2 x 7500 = 15,000m3, or 15,000,000kg (ignoring the salt in the water)
Therefore, max force is 147.2MN
Max work in 24 hours is 147.2 x 4 = 588.6MJ = 588,600kJ
Max work per second is 588,600/86,400 = 6.81kJ
Max power in = 6.81 kW
Power out = 3.0kw
Efficiency = 44.1%

(Or are you assuming one of the pontoons is going to spring a leak and sink?)

Ok, thanks for this. The idea that I was trying to get across was that (2) buoyancy engines working on this cycle would be able to share a single Pontoon owing to the sequencing of the loading of the Pontoon. This wouldn't be the optimum efficiency in terms of revenue generation for the system but it might be useful to suit certain demand profiles. The combined Pontoon would need to have an increased volume over (1) 7,500m3, maybe 10,000 - 12,000m3 would be possible with the main factor being distribution of stresses vs VfM. This would be subject to a detailed scaled design but since I haven't got the luxury of a design team behind me I will stick to the unitary system for now.

There are too many unknown variables at this point but I would anticipate that compared with other renewable energy systems the seasonal efficiency of a working system will be quite impressive.

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« Reply #144 on: 11/11/2011 20:38:42 »
Now I challenge you to answer the question in a straightforward manner or leave.

How will you make this rig cheap enough that the revenue will, at least, service the loan for building it?

As I've said (more than once,) I'm not ready to properly present and fully answer your question at this particular moment.

Once I've developed the Scaled and Construction Animation sufficiently I will return.

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« Reply #145 on: 12/11/2011 01:50:03 »
Yes, I did. As you didn't specify its displacement, I assumed it was twice the displacement of the two smaller ones. If you knew it was possible to generate the power output with half the total displacement, I would have thought you would have made that clear.

My calculation was simply the energy output over the maximum energy input based on the displacements and the tide.

I thought I did (3rd time lucky):
'Therefore, there is scope to engineer an arrangement such that both Storage Vessels operate from one Pontoon, which carries a number of operational and financial advantages.'

If you show your workings I can review further. The problem I have is that even when you are presented with irrefutable evidence you still don't concede points so I have no intention of trying to second guess what you have calculated.

OK - here you go.

Quote
Based on a 25:1 gearing ratio each Pontoon volume would be ca. 7,500m3
Tidal range is assumed as 2m.

Total displacement 2 x 7500 = 15,000m3, or 15,000,000kg (ignoring the salt in the water)
Therefore, max force is 147.2MN
Max work in 24 hours is 147.2 x 4 = 588.6MJ = 588,600kJ
Max work per second is 588,600/86,400 = 6.81kJ
Max power in = 6.81 kW
Power out = 3.0kw
Efficiency = 44.1%

(Or are you assuming one of the pontoons is going to spring a leak and sink?)

Ok, thanks for this. The idea that I was trying to get across was that (2) buoyancy engines working on this cycle would be able to share a single Pontoon owing to the sequencing of the loading of the Pontoon. This wouldn't be the optimum efficiency in terms of revenue generation for the system but it might be useful to suit certain demand profiles. The combined Pontoon would need to have an increased volume over (1) 7,500m3, maybe 10,000 - 12,000m3 would be possible with the main factor being distribution of stresses vs VfM. This would be subject to a detailed scaled design but since I haven't got the luxury of a design team behind me I will stick to the unitary system for now.

There are too many unknown variables at this point but I would anticipate that compared with other renewable energy systems the seasonal efficiency of a working system will be quite impressive.

Yes, I figured it was something like that.

BTW, I think you really need to worry about the 25:1 pulley speed up ratio. I'm pretty sure there will be so much friction that that pontoon will not be able to exert sufficient force on the storage vessel to move it.

In practice, even with a lot of anti-friction bearings (and super-flexible cable) I think you will discover there is no way around it. A small model of that part of the system might be a good investment.

An even cheaper method would be to get a 25:1 gear setup and try to run it in speed-up mode. If you have really good bearings, the output might actually rotate 25 times faster than the input under no load (although it's also possible the gears will strip before it turns at all), but as soon as you put any load on it, it will very likely wedge.   
There ain'ta no sanity clause, and there ain'ta no centrifugal force ĉther.

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Offline Bored chemist

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Will this buoyancy engine-based generator work?
« Reply #146 on: 12/11/2011 16:12:56 »
Now I challenge you to answer the question in a straightforward manner or leave.

How will you make this rig cheap enough that the revenue will, at least, service the loan for building it?

As I've said (more than once,) I'm not ready to properly present and fully answer your question at this particular moment.

Once I've developed the Scaled and Construction Animation sufficiently I will return.

An animation will not make it cheaper,
You could answer the question without that trouble.
You have mentioned a few things you will not do, but not what you will do instead.

I think you have absolutely no idea how you are going to make this idea economically viable.
Please disregard all previous signatures.

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Offline Mootle

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Will this buoyancy engine-based generator work?
« Reply #147 on: 13/11/2011 10:57:16 »
Now I challenge you to answer the question in a straightforward manner or leave.

How will you make this rig cheap enough that the revenue will, at least, service the loan for building it?

As I've said (more than once,) I'm not ready to properly present and fully answer your question at this particular moment.

Once I've developed the Scaled and Construction Animation sufficiently I will return.

An animation will not make it cheaper,
You could answer the question without that trouble.
You have mentioned a few things you will not do, but not what you will do instead.

I think you have absolutely no idea how you are going to make this idea economically viable.

The idea of this thread was to see if the system would work in principle.

Your speculations as to what ideas are in my head are noted but as the authority in this respect I assure you that you are wrong. I'm aware of the difficult challenges but have a number of innovative solutions in mind. Exploring these lines takes time but until the design is fixed the cost of the system is nothing more than a known unknown. This thread has reinforced a need to improve the available revenue and I'm satisfied that with a sensible balance of technologies I will have a reasonable shot at value engineering a solution which provides a reasonable business case.

Once I've developed my theorem to a point at which I'm ready to present I will return if that's OK.

Thank you for your patience.

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Offline Mootle

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Will this buoyancy engine-based generator work?
« Reply #148 on: 13/11/2011 11:19:43 »
Yes, I figured it was something like that.

BTW, I think you really need to worry about the 25:1 pulley speed up ratio. I'm pretty sure there will be so much friction that that pontoon will not be able to exert sufficient force on the storage vessel to move it.

In practice, even with a lot of anti-friction bearings (and super-flexible cable) I think you will discover there is no way around it. A small model of that part of the system might be a good investment.

An even cheaper method would be to get a 25:1 gear setup and try to run it in speed-up mode. If you have really good bearings, the output might actually rotate 25 times faster than the input under no load (although it's also possible the gears will strip before it turns at all), but as soon as you put any load on it, it will very likely wedge.  

Pulley's are still my preferred option as I haven't worked out how to make a gearbox solution work for this application but I'm still mulling that one over.

I've recognised the need to maintain load and this would be achieved by not allowing the Storage Vessel to break the surface following the Ascent phase, as stated on the audio of the Schematic animation. However, I acknowledge this isn't what's shown so apologies for the misunderstanding.

I agree that a lower ratio would be easier from an engineering perspective. The 25:1 ratio is a target driven by revenue optimisation. A pilot scheme is the next step but before I would look for scheme funding I need to be sure that there is a business case. If I can demonstrate a business case I would look to enter into consultation with specialists for a number of elements of the design where I'm not a practitioner. The pulley system would be one such area.

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Offline Geezer

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Will this buoyancy engine-based generator work?
« Reply #149 on: 13/11/2011 23:52:45 »
Yes, I figured it was something like that.

BTW, I think you really need to worry about the 25:1 pulley speed up ratio. I'm pretty sure there will be so much friction that that pontoon will not be able to exert sufficient force on the storage vessel to move it.

In practice, even with a lot of anti-friction bearings (and super-flexible cable) I think you will discover there is no way around it. A small model of that part of the system might be a good investment.

An even cheaper method would be to get a 25:1 gear setup and try to run it in speed-up mode. If you have really good bearings, the output might actually rotate 25 times faster than the input under no load (although it's also possible the gears will strip before it turns at all), but as soon as you put any load on it, it will very likely wedge.  

Pulley's are still my preferred option as I haven't worked out how to make a gearbox solution work for this application but I'm still mulling that one over.

I've recognised the need to maintain load and this would be achieved by not allowing the Storage Vessel to break the surface following the Ascent phase, as stated on the audio of the Schematic animation. However, I acknowledge this isn't what's shown so apologies for the misunderstanding.

I agree that a lower ratio would be easier from an engineering perspective. The 25:1 ratio is a target driven by revenue optimisation. A pilot scheme is the next step but before I would look for scheme funding I need to be sure that there is a business case. If I can demonstrate a business case I would look to enter into consultation with specialists for a number of elements of the design where I'm not a practitioner. The pulley system would be one such area.

Er, well, you might want to take a squint at this before you go much further, particularly the term that shows that the efficiency is related to the inverse of a value raised to the power of the number of sheaves. 25:1 is going to need a lot of sheaves. 

http://en.wikipedia.org/wiki/Block_and_tackle#Friction
There ain'ta no sanity clause, and there ain'ta no centrifugal force ĉther.