Tidal energy accumulator - Feasibility?

[Kittamaru]

Oooh, okay, I see waht you mean.

Well, there's an inherent issue with this I'm afraid... easiest way to demonstrate it would be as such:

Take an empty cup and stuff a crumpled paper towel into the bottom of it, then invert it. Place it in your sink on a few coins so there is a gap between the rim of the cup and the sink itself. Keep a hand on the cup to hold it down.

Now, fill the sink with water, keeping the cup held down so it doesn't float to the surface, and making sure to keep it open-end down. Once the water has risen over the top of the cup, feel free to drain it.

Take the paper towel out, and notice that it's dry.

The reason for this is the water cannot overcome the air pressure in the cup.

The same thing would happen with your idea - the tidal force wouldn't have enough pressure to build up more than a few PSI in that accumulator, not enough to do any significant workload.

 

[Quantum Quack]

Oooh, okay, I see waht you mean.

Well, there's an inherent issue with this I'm afraid... easiest way to demonstrate it would be as such:

Take an empty cup and stuff a crumpled paper towel into the bottom of it, then invert it. Place it in your sink on a few coins so there is a gap between the rim of the cup and the sink itself. Keep a hand on the cup to hold it down.

Now, fill the sink with water, keeping the cup held down so it doesn't float to the surface, and making sure to keep it open-end down. Once the water has risen over the top of the cup, feel free to drain it.

Take the paper towel out, and notice that it's dry.

The reason for this is the water cannot overcome the air pressure in the cup.

The same thing would happen with your idea - the tidal force wouldn't have enough pressure to build up more than a few PSI in that accumulator, not enough to do any significant workload.

ok... thanks for taking the idea seriously enough to provide feedback.

What if the pressure in the cup was significant say 100 psi [ at high tide ] and the storage vessel was large say 1000 cubic meters...
say we pump 100 psi into the storage unit every tidal stroke... we would end up with a large storage of 1000 cubic meters at 100psi yes?
Then say we use a small volume of that storage on a daily basis in a way that sustains a reliable pressure at say 80psi.
Have we not managed to achieve a sustainable and natural energy source to run pneumatic tools, generators etc?
at virtually no cost...of running.

 

[Quantum Quack]

If you take an extreme such as the Bay of Fundy where the vertical tide is 50 feet.
You place a vertically arranged pipe of say 12" inside diameter and seal the upper end. Leaving the lower end exposed to be filled by the incoming tide.
Would the pressure inside the pipe be significant at high tide? [ given that the entry point is 50 feet below the water surface ]
edit ok.. I did a little research.
Every foot of sea water is .445lbs
At 50 feet that makes a grand total of a mere 22.25psi.

so you are right, the pressure achievable is insignificant..even at extreme tidal flows.
hmmmm....

 

[billvon]

If you take an extreme such as the Bay of Fundy where the vertical tide is 50 feet.
You place a vertically arranged pipe of say 12" inside diameter and seal the upper end. Leaving the lower end exposed to be filled by the incoming tide.
Would the pressure inside the pipe be significant at high tide? [ given that the entry point is 50 feet below the water surface ]

If you had a pipe completely full of air you would get a max of 25 PSI over ambient (roughly .5 PSI per foot of water.) However, as the water rises it will compress the air, the water will rise, and total available pressure will be significantly lower.

 

[Quantum Quack]

yes... a non goer... maybe though there is some other way of using the vertical tidal forces like an articulated float system [unfortunately moving parts involved]

 

[Russ_Watters]

The thing to realize is that at very low cost we humans could be accumulating pressure [ thus usable energy ] over an extended time period in a sustainable fashion by using the rise and fall of the tides as an air pump.

@read_only, so why do you think it is a dead idea?

It is a dead idea because it has been tried and proven not to be economical. The problem with your analysis is that you've only done half the analysis and even that half poorly. You calculated a potential savings then stated that it is "at very low cost" instead of trying to calculate the cost. The fact of the matter is that for the amount of energy you get, the cost is very, very high.

 

[Kittamaru]

The problem is, Quantum, there is very little inherent energy in the vertical motion of the tides... what gives them their strength is sheer quantity of... well, water. Short of covering entire shorelines with devices to harness it, there just isn't much that can be done to capture any significant amount of energy. Moving parts aren't really that big a deal though, and that's why the horizontal tidal-force generators are of such interest.

 

[Quantum Quack]

It is a dead idea because it has been tried and proven not to be economical. The problem with your analysis is that you've only done half the analysis and even that half poorly. You calculated a potential savings then stated that it is "at very low cost" instead of trying to calculate the cost. The fact of the matter is that for the amount of energy you get, the cost is very, very high.

My biggest mistake was to assume a significant pressure would be present and more importantly "presume" I was correct in that assumption. [forgetting about all the scuba diving I had done as a teen...] a differential of <10 or so psi relative to atmospheric pressure has not much of a potential.

and you are correct given the small amount of energy achieved the cost would be too high.
as read_only stated with out explaining the idea is a dead idea...

 

[Quantum Quack]

The problem is, Quantum, there is very little inherent energy in the vertical motion of the tides... what gives them their strength is sheer quantity of... well, water. Short of covering entire shorelines with devices to harness it, there just isn't much that can be done to capture any significant amount of energy. Moving parts aren't really that big a deal though, and that's why the horizontal tidal-force generators are of such interest.

I tend to agree with you yet in another sense there is tremendous inherent energy given that an enormous tonnage of water is moving up and down at such a regular interval. We just do not know how to harness this vertical movement in a way that makes sense. [other than by using dams]

The attraction to this idea was due to the simplicity and low capital cost and ultra long term gain....
high volume /low profit = big overall gain type system

For example if there was a use for a 5psi stored pressure derived from a few vertical pipes hanging of a jetty that cost nothing to maintain for 100's of years then that 5psi delivered over an extended amount of time could be of enormous accumulated value. As it stands I don't think we have any devices that could run on such low pressure input.

 

[Read-Only]

Quantum, Read Only, you are on two very different wavelengths at the moment I think...

Quantum, if I understand you correctly, you want to use the rising tide to pressurize a chamber of fresh water that can then be used to turn turbines as the tide goes out.

That, or you want to use the water rising inside the chamber to spin the turbines ( you seem to have presented two different ideas)

There is no real need for this; already, they have harnessed the motion of the tide via turbines that spin as the tide flows in and out along the shoreline. Essentially, it's like using the movement of the tide as it ebbs and flows in a way similar to the movement of water in a river turns a water wheel. Essentially, the same thing you are proposing, but horizontally instead of vertically, resulting in much reduced construction costs.


There are several proposed designs for this, from the standard windmill design:

View attachment 6848

To more environmentally safe (for the wildlife) helix designs:

View attachment 6849

Also, I'm not sure why this is in pseudoscience... I mean, these things are actually in use in some areas so... not very "pseudo" at this point

Not really. What I proposed is actually the exact same thing you described - and it's been in use for decades around the world.

 

[BdS]

View attachment 6855


Targeting the waves momentum might be more profitable. Depending on the width of the buoy kite is how much momentum we could target and convert to electrical energy. The diagram is in 2d the kite could be quite wide, each kite can have multiple cables or pipes attached between the generator pulleys and kite. I wonder if its even possible to make a kite device that can lock into the waves momentum and can survive the harsh conditions? The diagram is a example of a system to theoretically target the waves momentum.

 

[Quantum Quack]

View attachment 6855


Targeting the waves momentum might be more profitable. Depending on the width of the buoy kite is how much momentum we could target and convert to electrical energy. The diagram is in 2d the kite could be quite wide, each kite can have multiple cables or pipes attached between the generator pulleys and kite. I wonder if its even possible to make a kite device that can lock into the waves momentum and can survive the harsh conditions? The diagram is a example of a system to theoretically target the waves momentum.

I like the idea!

 

[billvon]

yes... a non goer... maybe though there is some other way of using the vertical tidal forces like an articulated float system [unfortunately moving parts involved]

Wave energy has been captured that way. Tidal energy is generally captured via underwater turbines.

 

[Quantum Quack]

Wave energy has been captured that way. Tidal energy is generally captured via underwater turbines.

Yes but I believe in the longer term, using the vertical height changes may prove more effective.

I realized that the idea at the start of this thread may do better if the pumping action is achieved on the downward stroke. [tide going out]
Imagines a vertical cylinder that fills with sea water as the tide comes in. That water can be made to remain suspended until the optimum moment and generate a considerable low pressure potential that could go on to generate air pressure.
If I get the chance I'll do some gifs....

 

[Quantum Quack]

ok..try this and see if it makes any sense...[basic model - tidal air pump]

the general idea is that the weight of the suspended water determines the amount of "air pressure" available to be stored.
The animation's not the best but will have to do for now.

 

[Quantum Quack]

The funny thing is I didn't bother to do a Google on tidal pumps until now and... well ... there is a significant number of ideas out there associated.
One such idea presented c/o Stanford University. (Chuck Eeasley)
ref: https://novoed.com/venture/pitch_decks/180
[I am not too keen on the design offered btw]

The challenge:
To design a tidal pump that has:
1] Minimal construction cost.
2] Minimal or no maintenance required.
3] No moving parts ["if possible]
4] Extreme longevity of function. [thousands of years]
5] Portability of acquired energy potential.
6] Global application.

Inspired by the Roman Empires' approach to infrastructure, as far as durability and simplicity is concerned.

Any thoughts are more than welcome!

 

[BdS]

View attachment 6908
Capture the water at high tide in a pool, then use the extra gravitational potential of the captured water at low tide to generate energy, with a water wheel or any device that can convert the extra potential to another form of useful energy.



View attachment 6909

This system also uses extra gravitational potential to generate useful energy. The system would use the waves momentum to fill or keep topping up the water in the elevated pool, then use the extra gravitational potential of the captured water to generate energy, with a water wheel or any device that can convert the extra potential to another form of useful energy.

 

[Quantum Quack]

Capture the water at high tide in a pool, then use the extra gravitational potential of the captured water at low tide to generate energy, with a water wheel or any device that can convert the extra potential to another form of useful energy.

I like this in principle as it is maintenance free low cost to build and has no moving parts.[ so far ]

Bds's diagram

 

[exchemist]

I like this in principle as it is maintenance free low cost to build and has no moving parts.[ so far ]

Bds's diagram

You think this hasn't been done? The French have had a tidal barrage on the Rance at St Malo since the 1960s, using exactly this principle.

And in the UK there has been much discussion about a similar, far bigger, one, on the Severn estuary. In both cases the very high tidal range >10m makes it espeicially attractive.

Though of course it does have moving parts (the turbines and sluices) and is thus not maintenance-free. But then no machine is maintenance-free.

 

[Quantum Quack]

You think this hasn't been done? The French have had a tidal barrage on the Rance at St Malo since the 1960s, using exactly this principle.

And in the UK there has been much discussion about a similar, far bigger, one, on the Severn estuary. In both cases the very high tidal range >10m makes it especially attractive.

Though of course it does have moving parts (the turbines and sluices) and is thus not maintenance-free. But then no machine is maintenance-free.

Of course Not! Tidal mills have been around since Roman times.

The key aspect of this thread is to find a clever way to make use of the vertical movement of tides that can endure virtually maintenance free for thousands of years. [ ie. no moving parts ]
Even this :

the image (*.gif image) of which I generated a while ago has a piston or ram structure and at least 2 poppet valves, which means that unless really clever in construction would have inherent short to medium term maintenance issues.
[The idea to avoid technology having to be in contact with salt water. Pressuring air to be piped out to a large storage container and used later for what ever purposes necessary.]

I keep feeling though, and I might be chasing a rabbit with this, - that there may be a really clever way to use the water and structure that involves no moving parts [ no piston or ram ] and achieve the same result.
Which would mean you could construct these things under a beach and basically "forget about them" and simply make use of the output pressure.

There would be no contact with salt water other than pipes and possibly crude but clever pistons.

*if you can't see the animation let me know