Pressure Harvesting - from ocean depths

Discussion in 'General Science & Technology' started by Quantum Quack, Mar 8, 2020.

1. Quantum QuackLife's a tease...Valued Senior Member

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Most of this thread is filled with posts that have no idea about fluid mechanics. And I am a complete novice...yet even I can see how displacement can provide potential energy. (You are adding pressure by displacement to only extract it later at depth) Being a one way trip and totally uneconomical doesn't change the physics. A smart person may come up with a method to make it so...

3. billvonValued Senior Member

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So prove me wrong. Build an "ocean energy harvester." Learn the hard way, as tens of thousands of other perpetual motion believers have.

5. Quantum QuackLife's a tease...Valued Senior Member

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wegs
see what I mean...
This bizarre fear and preoccupation with perpetual energy devices has nothing to do with physics or more specifically fluid mechanics.

Last edited: Nov 3, 2020

7. Quantum QuackLife's a tease...Valued Senior Member

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I already know it isn't a perpetual motion or energy device, why don't you?

8. SeattleValued Senior Member

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Are we dealing with mental illness here?

9. billvonValued Senior Member

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Once again, it is not a source of energy, any more than a rock is. It doesn't work as a source of energy in real life. Note the last three words there; they are important.

10. Quantum QuackLife's a tease...Valued Senior Member

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Are they?
Why?
Just because you say so... sure...

11. Quantum QuackLife's a tease...Valued Senior Member

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You still haven't explained why you think it is a perpetual motion device...

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Rep

13. wegsMatter and Pixie DustValued Senior Member

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Your thread has intrigued me, QQ. There was an experimental project a few years back in Portland Oregon, and researchers tried to get it off the ground, but they built a 260 ton buoy that would turn the movement of the ocean into electricity to power 100 homes. The cost at that point was around $8 million. 100 homes at$8 million investment? (and \$60 million was still needed to continue the project)

So, the company (Ocean Power Technologies) ended up abandoning the project, entirely. It was sad to read about this, as they were very close to getting the buoy in the water, but...big dreams like this take money, and when the alternatives are much cheaper, it's easy to see why this idea was scrapped. But, the future is bright with innovations like this, for sure. Keep dreamin'

(I'd say that OPT is a pioneer in this arena, and I'm not sure if they've successfully started another project and received proper funding, yet. Check out that company for more info)

Last edited: Nov 4, 2020
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14. SeattleValued Senior Member

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Yes, he (and everyone else) has. It's the First Law of Thermodynamics. You are trying to create more energy than you are applying (otherwise why do it?). It can't be done at a fundamental level. It's not a matter of bringing costs down one day. If that were the case, that could possibly be done. That's not the problem being addressed here.

If violates the First Law of Thermodynamics. That's not something that is going to change with a little more technology.

You object to your idea being called a perpetual energy machine because that's not what you call it but that is still what it would have to be as you've described it.

Therefore since your plan would use more energy than it produces, it's more efficient to not do it. It doesn't add anything to the problem. To keep telling an engineer (Billvon not me) that he doesn't understand Fluid Dynamics (a phrase you just learned a few days ago) is ridiculous.

Violating the fundamental energy laws and then continuing to argue about it is just silly. To have to tell you this on post 671 is ridiculous. That you probably won't read this because you have me on ignore is even more ridiculous.

This is how all of your threads go however so I guess it shouldn't be a surprise at this point.

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15. Q-reeusBannedValued Senior Member

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Wave power technologies, which at least are realizable in principle, are a dime a dozen. There are many startups and proof-of-principle projects that get initial glowing prognoses and seed capital, but subsequently 'disappear beneath the waves'. About every conceivable angle has been explored. To come up with something truly new and viable is a huge ask. At best it represents a niche technology, with inherently high overall maintenance costs, that could never make a significant contribution to global energy requirements.

16. SeattleValued Senior Member

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I agree with most of your points but, in principle, it is similar to wind turbine technology is it not? Of course that isn't making a significant contribution either but it is commercially viable although maybe that is only due to government subsidies?

17. wegsMatter and Pixie DustValued Senior Member

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Putting it simply, operating in the ocean is just harder than on land. Probably why the cost is so high, and why companies abandon their plans. It's a cool concept, though.

18. exchemistValued Senior Member

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Yes I think so. Senility, probably.

19. exchemistValued Senior Member

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Wind contributed about 25% of electricity generation in the UK and Germany last year.

20. billvonValued Senior Member

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Yeah, I've seen about a dozen designs for those, from shore-mounted rams to floating buoys to long serpentine buoys that flex as the wave passes. The problem all of them face is that they are trying to harvest moderate amplitude, very high force but very low frequency energy. And that generally requires very heavy equipment, which doesn't translate to "cheap."

Tidal power is similar. You can get millions of tons of water to flow in and out of a tidal impoundment but again there's a lot of water and it's moving slowly, so you need large/expensive equipment to harvest it. If tides were 100 feet or so it would work very well - but as it stands average tides are about 2 feet, with very few places seeing 40 feet.

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21. wegsMatter and Pixie DustValued Senior Member

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I've read that wind energy is becoming more cost competitive, too.

22. Q-reeusBannedValued Senior Member

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Wind turbines are a mixed bag. The current crop of tri-bladed ones that clutter the landscape in many countries have serious drawbacks. At least according to some serious studies:
http://www.windaction.org/
http://www.windaction.org/posts/504...g-mistake-that-make-wind-turbines-inefficient

There are however new bladeless designs that are touted as the answer to the drawbacks of existing mega-wind-farms:

Even if such truly overcomes the high maintenance issues of bladed designs, bladeless farms cannot extract significantly more energy per acre than existing designs, hence will still clutter the landscape as acre hungry hogs. Solar farms have much the same issues though they have greater flexibility e.g. feasible to erect on suburban dwelling rooftops.

23. SeattleValued Senior Member

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The bladed designs that I've seen tend to be in places where either land isn't all that valuable or it's hilly and not useful for farming. They are all over Kauai but they are in hilly areas where it's too steep for houses. You can say they are a visual eyesore but that's subjective I guess.

In the Midwest you see them on farms in areas that are not as useful for farming (along a ditch or whatever). A couple of hours outside of Seattle, near an area where I go rock climbing, there is some farming but there is little water (high desert area) and there is a lot of wind due to the Cascades and there are many bladed designs on the ridges of the hills.

So they are all over and they must be somewhat economical.